The genetic legacy of fragmentation and overexploitation in the threatened medicinal African pepper-bark tree, Warburgia salutaris:
- Senkoro, Annae M, Talhinhas, Pedro, Simões, Fernanda, Batista-Santos, Paula, Shackleton, Charlie M, Voeks, Robert A, Marques, Isabel, Ribeiro-Barros, Ana I
- Authors: Senkoro, Annae M , Talhinhas, Pedro , Simões, Fernanda , Batista-Santos, Paula , Shackleton, Charlie M , Voeks, Robert A , Marques, Isabel , Ribeiro-Barros, Ana I
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/176395 , vital:42690 , https://doi.org/10.1016/j.ecoser.2020.101201
- Description: The pepper-bark tree (Warburgia salutaris) is one of the most highly valued medicinal plant species worldwide. Native to southern Africa, this species has been extensively harvested for the bark, which is widely used in traditional health practices. Illegal harvesting coupled with habitat degradation has contributed to fragmentation of populations and a severe decline in its distribution. Even though the species is included in the IUCN Red List as Endangered, genetic data that would help conservation efforts and future re-introductions are absent. We therefore developed new molecular markers to understand patterns of genetic diversity, structure, and gene flow of W. salutaris in one of its most important areas of occurrence (Mozambique).
- Full Text:
- Date Issued: 2020
- Authors: Senkoro, Annae M , Talhinhas, Pedro , Simões, Fernanda , Batista-Santos, Paula , Shackleton, Charlie M , Voeks, Robert A , Marques, Isabel , Ribeiro-Barros, Ana I
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/176395 , vital:42690 , https://doi.org/10.1016/j.ecoser.2020.101201
- Description: The pepper-bark tree (Warburgia salutaris) is one of the most highly valued medicinal plant species worldwide. Native to southern Africa, this species has been extensively harvested for the bark, which is widely used in traditional health practices. Illegal harvesting coupled with habitat degradation has contributed to fragmentation of populations and a severe decline in its distribution. Even though the species is included in the IUCN Red List as Endangered, genetic data that would help conservation efforts and future re-introductions are absent. We therefore developed new molecular markers to understand patterns of genetic diversity, structure, and gene flow of W. salutaris in one of its most important areas of occurrence (Mozambique).
- Full Text:
- Date Issued: 2020
Factors associated with consistent condom use: a cross-sectional survey of two Nigerian universities
- Ajayi, Anthony Idowu, Ismail , Kafayat Olanike, Akpan, Wilson
- Authors: Ajayi, Anthony Idowu , Ismail , Kafayat Olanike , Akpan, Wilson
- Date: 2019
- Subjects: Nigeria Condom Use Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5834 , vital:44650 , https://DOI:10.1186/s12889-019-7543-1
- Description: Background: Consistent condom use is central to the prevention of transmission of human immunodeficiency virus (HIV) and other sexually transmitted diseases (STDs), especially among young adults. This study drew from a cross-sectional survey of two Nigerian universities to determine the level of consistent condom use, explored the determinants of condom use consistency and reasons for inconsistent condom use. Methods: We adopted a descriptive cross-sectional design, which involves the recruitment of 800 male and female students using stratified random sampling. Adjusted and unadjusted logistic regression models were used to examine the factors associated with consistent condom use among a final sample of 498 students who engaged in sex in the last year preceding the study. Results: Only 38.6% of sexually active participants (n = 498) used condoms consistently in the previous year. High condom self-efficacy score (AOR: 2.40; 95% CI: 1.58–3.64), discussion of HIV/STIs with sexual partner (AOR: 1.91; 95%CI: 1.29–2.83), knowing partner’s HIV status (AOR: 1.48; 95% CI: 1.02–2.16), being students of university located in a high HIV prevalence area (AOR: 2.86; 95% CI: 1.92–4.28) and engaging in sex with only steady partner (AOR: 1.74; 95% CI: 1.17–2.60) were associated with a higher odds of consistent condom use. Trust, unavailability of condoms, dislike of condoms and a perception that condoms reduced sexual pleasure were the main reasons for inconsistent use of condoms. Conclusion: The study found a low level of consistent condom use among study participants. Counselling young adults in Nigeria on condom self-efficacy, providing condoms on campuses and encouraging the discussion of sexually transmitted infections with sexual partners are central to improving the level of consistent condom use among Nigerian university students. Keywords: Condoms, Self-efficacy, Consistent condom use, HIV, Drug use, Alcohol use, Nigeria, University students
- Full Text:
- Date Issued: 2019
Factors associated with consistent condom use: a cross-sectional survey of two Nigerian universities
- Authors: Ajayi, Anthony Idowu , Ismail , Kafayat Olanike , Akpan, Wilson
- Date: 2019
- Subjects: Nigeria Condom Use Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5834 , vital:44650 , https://DOI:10.1186/s12889-019-7543-1
- Description: Background: Consistent condom use is central to the prevention of transmission of human immunodeficiency virus (HIV) and other sexually transmitted diseases (STDs), especially among young adults. This study drew from a cross-sectional survey of two Nigerian universities to determine the level of consistent condom use, explored the determinants of condom use consistency and reasons for inconsistent condom use. Methods: We adopted a descriptive cross-sectional design, which involves the recruitment of 800 male and female students using stratified random sampling. Adjusted and unadjusted logistic regression models were used to examine the factors associated with consistent condom use among a final sample of 498 students who engaged in sex in the last year preceding the study. Results: Only 38.6% of sexually active participants (n = 498) used condoms consistently in the previous year. High condom self-efficacy score (AOR: 2.40; 95% CI: 1.58–3.64), discussion of HIV/STIs with sexual partner (AOR: 1.91; 95%CI: 1.29–2.83), knowing partner’s HIV status (AOR: 1.48; 95% CI: 1.02–2.16), being students of university located in a high HIV prevalence area (AOR: 2.86; 95% CI: 1.92–4.28) and engaging in sex with only steady partner (AOR: 1.74; 95% CI: 1.17–2.60) were associated with a higher odds of consistent condom use. Trust, unavailability of condoms, dislike of condoms and a perception that condoms reduced sexual pleasure were the main reasons for inconsistent use of condoms. Conclusion: The study found a low level of consistent condom use among study participants. Counselling young adults in Nigeria on condom self-efficacy, providing condoms on campuses and encouraging the discussion of sexually transmitted infections with sexual partners are central to improving the level of consistent condom use among Nigerian university students. Keywords: Condoms, Self-efficacy, Consistent condom use, HIV, Drug use, Alcohol use, Nigeria, University students
- Full Text:
- Date Issued: 2019
Perceptions and preferences for urban trees across multiple socio-economic contexts in the Eastern Cape, South Africa
- Gwedla, Nanamhla, Shackleton, Charlie M
- Authors: Gwedla, Nanamhla , Shackleton, Charlie M
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177419 , vital:42820 , https://doi.org/10.1016/j.landurbplan.2019.05.001
- Description: Urban trees are vital components of urban ecosystems, and thus important for environmental quality, urban sustainability, and quality of life in cities. Regrettably, urban trees are sometimes unequally distributed both between and within towns, a pattern largely associated with differences in the social environment of cities and historical patterns of development, and the dearth in strategic management plans and systematic monitoring of the existing urban forest. Most management plans focus on ecological and arboricultural aspects at the expense of the social, and studies examining perceptions in relation urban forests are largely from developed countries. Accordingly, we conducted a study to examine the perceptions and preferences regarding urban trees of 1200 residents from 10 urban areas across multiple socio-economic contexts in South Africa.
- Full Text:
- Date Issued: 2019
- Authors: Gwedla, Nanamhla , Shackleton, Charlie M
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177419 , vital:42820 , https://doi.org/10.1016/j.landurbplan.2019.05.001
- Description: Urban trees are vital components of urban ecosystems, and thus important for environmental quality, urban sustainability, and quality of life in cities. Regrettably, urban trees are sometimes unequally distributed both between and within towns, a pattern largely associated with differences in the social environment of cities and historical patterns of development, and the dearth in strategic management plans and systematic monitoring of the existing urban forest. Most management plans focus on ecological and arboricultural aspects at the expense of the social, and studies examining perceptions in relation urban forests are largely from developed countries. Accordingly, we conducted a study to examine the perceptions and preferences regarding urban trees of 1200 residents from 10 urban areas across multiple socio-economic contexts in South Africa.
- Full Text:
- Date Issued: 2019
Rapid recovery of macroinvertebrates in a South African stream treated with rotenone:
- Bellingan, Terence A, Hugo, Sanet, Woodford, Darragh J, Gouws, Jeanne, Villet, Martin H, Weyl, Olaf L F
- Authors: Bellingan, Terence A , Hugo, Sanet , Woodford, Darragh J , Gouws, Jeanne , Villet, Martin H , Weyl, Olaf L F
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140751 , vital:37915 , DOI: 10.1007/s10750-019-3885-z
- Description: South Africa’s Cape Fold Ecoregion supports a unique freshwater fish assemblage with many endemics. To mitigate impacts of alien invasive fishes on this unique assemblage, nature conservation authority CapeNature used rotenone to remove smallmouth bass (Micropterus dolomieu) from the Rondegat River. We investigated whether the rotenone treatments had an adverse impact on the aquatic macroinvertebrate community over the long-term, the first study of its kind in Africa. We monitored macroinvertebrates within treated and untreated (control) sites on multiple sampling events for 2 years before and 2 years after two rotenone treatments. We analysed the difference in invertebrate abundance between treatment and control sites before and after treatment, using generalised linear mixed models with sampling event as a random factor to partition out natural fluctuations in abundances over time.
- Full Text:
- Date Issued: 2019
- Authors: Bellingan, Terence A , Hugo, Sanet , Woodford, Darragh J , Gouws, Jeanne , Villet, Martin H , Weyl, Olaf L F
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140751 , vital:37915 , DOI: 10.1007/s10750-019-3885-z
- Description: South Africa’s Cape Fold Ecoregion supports a unique freshwater fish assemblage with many endemics. To mitigate impacts of alien invasive fishes on this unique assemblage, nature conservation authority CapeNature used rotenone to remove smallmouth bass (Micropterus dolomieu) from the Rondegat River. We investigated whether the rotenone treatments had an adverse impact on the aquatic macroinvertebrate community over the long-term, the first study of its kind in Africa. We monitored macroinvertebrates within treated and untreated (control) sites on multiple sampling events for 2 years before and 2 years after two rotenone treatments. We analysed the difference in invertebrate abundance between treatment and control sites before and after treatment, using generalised linear mixed models with sampling event as a random factor to partition out natural fluctuations in abundances over time.
- Full Text:
- Date Issued: 2019
Strength and Sprint Time Changes in Response to Repeated Shuttles Between the Wickets During Batting in Cricket
- Christie, Candice J, Sheppard, Bronwyn J, Goble, David, Pote, Lee, Noakes, Timothy
- Authors: Christie, Candice J , Sheppard, Bronwyn J , Goble, David , Pote, Lee , Noakes, Timothy
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127133 , vital:35959 , https://doi.org/10.1519/jsc.0000000000002585
- Description: Christie CJ, Sheppard B, Goble D, Pote L, and Noakes TD. Strength and sprint time changes in response to repeated shuttles between the wickets during batting in cricket. J Strength Cond Res XX(X): 000–000, 2018—No studies have investigated the impact of repeated sprints between the wickets on lower-limb strength and sprint performance. Therefore, the purpose of this study was to assess changes in knee extensor (EXT) and flexor (FLEX) strength after repeated sprints between the wickets and to relate these to changes in sprint times. Twenty batters completed 2 conditions: onewas high-volume running (HVR-twelve sprints per over) and the other, moderate-volume running (MVR-6 sprints per over) between the wickets (42 deliveries in both). Peak isokinetic torque was measured before and after each condition and sprint times were recorded. Eccentric and concentric peak torque decreased significantly (p , 0.05) at 1.05 rad˙s ̄1 for knee EXT in both conditions. There was an 18% (HVR) and 10% (MVR) decline in concentric and eccentric knee EXT peak torque. Peak FLEX torques were significantly (p , 0.05) reduced after HVR (16.7%) but not after the MVR condition (8%). There were similar declines in eccentric FLEX peak torque. Sprint times increased significantly (p , 0.05) during the HVR condition but not in the MVR condition; sprint times in the HVR condition were compromised as early as the third over. We conclude that a high volume of runs significantly reduces muscle function in the lower limbs, partly explaining the impairment in sprint performance. However, because batters slowed as early as the third over in the HVR condition, there may be some form of strategy used in anticipation of a higher overall workload. More middle wicket practices, focusing on repeat shuttle sprints while batting, should be included in the coaching program.
- Full Text:
- Date Issued: 2019
- Authors: Christie, Candice J , Sheppard, Bronwyn J , Goble, David , Pote, Lee , Noakes, Timothy
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127133 , vital:35959 , https://doi.org/10.1519/jsc.0000000000002585
- Description: Christie CJ, Sheppard B, Goble D, Pote L, and Noakes TD. Strength and sprint time changes in response to repeated shuttles between the wickets during batting in cricket. J Strength Cond Res XX(X): 000–000, 2018—No studies have investigated the impact of repeated sprints between the wickets on lower-limb strength and sprint performance. Therefore, the purpose of this study was to assess changes in knee extensor (EXT) and flexor (FLEX) strength after repeated sprints between the wickets and to relate these to changes in sprint times. Twenty batters completed 2 conditions: onewas high-volume running (HVR-twelve sprints per over) and the other, moderate-volume running (MVR-6 sprints per over) between the wickets (42 deliveries in both). Peak isokinetic torque was measured before and after each condition and sprint times were recorded. Eccentric and concentric peak torque decreased significantly (p , 0.05) at 1.05 rad˙s ̄1 for knee EXT in both conditions. There was an 18% (HVR) and 10% (MVR) decline in concentric and eccentric knee EXT peak torque. Peak FLEX torques were significantly (p , 0.05) reduced after HVR (16.7%) but not after the MVR condition (8%). There were similar declines in eccentric FLEX peak torque. Sprint times increased significantly (p , 0.05) during the HVR condition but not in the MVR condition; sprint times in the HVR condition were compromised as early as the third over. We conclude that a high volume of runs significantly reduces muscle function in the lower limbs, partly explaining the impairment in sprint performance. However, because batters slowed as early as the third over in the HVR condition, there may be some form of strategy used in anticipation of a higher overall workload. More middle wicket practices, focusing on repeat shuttle sprints while batting, should be included in the coaching program.
- Full Text:
- Date Issued: 2019
The diet and trophic ecology of non-native Micropterus salmoides in two South African impoundments
- Taylor, Geraldine C, Hill, Jaclyn M, Weyl, Olaf L F
- Authors: Taylor, Geraldine C , Hill, Jaclyn M , Weyl, Olaf L F
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444718 , vital:74262 , https://doi.org/10.2989/16085914.2019.1612318
- Description: Largemouth bass Micropterus salmoides is a highly successful predator that preys on fish and invertebrates. Highly popular with anglers, it is one of the most introduced and invasive fish globally, with strong potential to alter ecosystem structure and functioning. A better understanding of the trophic dynamics of M. salmoides populations is critical for effective management of its ecological impacts in their invasive range. This study investigated the diets and dietary ontogenetic shifts of M. salmoides in two South African dams along with its trophic positioning relative to other fish community members, through stomach content and stable isotope analyses. Micropterus salmoides was a top predator in both dams. In the Mankazana Dam, it depended predominately on insect prey, demonstrating a generalised feeding strategy, with shifts to include increasing proportions of fish prey with increasing size. Contrastingly, in the Wriggleswade Dam, M. salmoides displayed no ontogenetic shifts and preferred Gilchristella aestuaria, likely indicating a shift to a predominantly fish-based diet at smaller sizes, in the presence of small pelagic fish prey. Overall, M. salmoides diet was opportunistic, likely associated with prey morphology and behaviour (associated with refuge availability) and therefore directly linked to prey abundance and availability, which consequently dictated feeding strategy.
- Full Text:
- Date Issued: 2019
- Authors: Taylor, Geraldine C , Hill, Jaclyn M , Weyl, Olaf L F
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444718 , vital:74262 , https://doi.org/10.2989/16085914.2019.1612318
- Description: Largemouth bass Micropterus salmoides is a highly successful predator that preys on fish and invertebrates. Highly popular with anglers, it is one of the most introduced and invasive fish globally, with strong potential to alter ecosystem structure and functioning. A better understanding of the trophic dynamics of M. salmoides populations is critical for effective management of its ecological impacts in their invasive range. This study investigated the diets and dietary ontogenetic shifts of M. salmoides in two South African dams along with its trophic positioning relative to other fish community members, through stomach content and stable isotope analyses. Micropterus salmoides was a top predator in both dams. In the Mankazana Dam, it depended predominately on insect prey, demonstrating a generalised feeding strategy, with shifts to include increasing proportions of fish prey with increasing size. Contrastingly, in the Wriggleswade Dam, M. salmoides displayed no ontogenetic shifts and preferred Gilchristella aestuaria, likely indicating a shift to a predominantly fish-based diet at smaller sizes, in the presence of small pelagic fish prey. Overall, M. salmoides diet was opportunistic, likely associated with prey morphology and behaviour (associated with refuge availability) and therefore directly linked to prey abundance and availability, which consequently dictated feeding strategy.
- Full Text:
- Date Issued: 2019
The functional significance of facultative hyperthermia varies with body size and phylogeny in birds
- Gerson, Alexander R, McKechnie, Andrew, Smit, Ben, Whitfield, Maxine C, Smith, Eric K, Talbot, William A, McWhorter, Todd J, Wolf, Blair O
- Authors: Gerson, Alexander R , McKechnie, Andrew , Smit, Ben , Whitfield, Maxine C , Smith, Eric K , Talbot, William A , McWhorter, Todd J , Wolf, Blair O
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441609 , vital:73901 , https://doi.org/10.1111/1365-2435.13274
- Description: Facultative hyperthermia, the elevation of body temperature above normothermic levels, during heat exposure, importantly affects the wa-ter economy and heat balance of terrestrial endotherms. We currently lack a mechanistic understanding of the benefits hyperthermia provides for avian taxa. Facultative hyperthermia has been proposed to minimize rates of water loss via three distinct mechanisms: M1) by maintaining body temperature (Tb) above environmental temperatures (Te), heat can be lost non‐evaporatively, saving water; M2) by minimizing the thermal gradient when Te > Tb, environmental heat gain and evaporative water loss rates are reduced; and M3) by storing heat via increases in Tb which reduces evaporative heat loss demands and conserves wa-ter. Although individuals may benefit from all three mechanisms during heat exposure, the relative importance of each mechanism has not been quantified among species that differ in their body size, heat toler-ance and mechanisms of evaporative heat dissipation. We measured resting metabolism, evaporative water loss and real‐time Tb from 33 species of birds representing nine orders ranging in mass from 8 to 300 g and estimated the water savings associated with each proposed mechanism. We show that facultative hyperthermia varies in its benefits among species.
- Full Text:
- Date Issued: 2019
The functional significance of facultative hyperthermia varies with body size and phylogeny in birds
- Authors: Gerson, Alexander R , McKechnie, Andrew , Smit, Ben , Whitfield, Maxine C , Smith, Eric K , Talbot, William A , McWhorter, Todd J , Wolf, Blair O
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441609 , vital:73901 , https://doi.org/10.1111/1365-2435.13274
- Description: Facultative hyperthermia, the elevation of body temperature above normothermic levels, during heat exposure, importantly affects the wa-ter economy and heat balance of terrestrial endotherms. We currently lack a mechanistic understanding of the benefits hyperthermia provides for avian taxa. Facultative hyperthermia has been proposed to minimize rates of water loss via three distinct mechanisms: M1) by maintaining body temperature (Tb) above environmental temperatures (Te), heat can be lost non‐evaporatively, saving water; M2) by minimizing the thermal gradient when Te > Tb, environmental heat gain and evaporative water loss rates are reduced; and M3) by storing heat via increases in Tb which reduces evaporative heat loss demands and conserves wa-ter. Although individuals may benefit from all three mechanisms during heat exposure, the relative importance of each mechanism has not been quantified among species that differ in their body size, heat toler-ance and mechanisms of evaporative heat dissipation. We measured resting metabolism, evaporative water loss and real‐time Tb from 33 species of birds representing nine orders ranging in mass from 8 to 300 g and estimated the water savings associated with each proposed mechanism. We show that facultative hyperthermia varies in its benefits among species.
- Full Text:
- Date Issued: 2019
Tracking the decline of the world’s largest seabream against policy adjustments
- Kerwath, Sven E, Parker, Denham, Winker, A Henning, Potts, Warren M, Mann, Bruce Q, Wilke, Christopher, Attwood, Colin G
- Authors: Kerwath, Sven E , Parker, Denham , Winker, A Henning , Potts, Warren M , Mann, Bruce Q , Wilke, Christopher , Attwood, Colin G
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131433 , vital:36571 , https://doi.org/10.3354/meps12853
- Description: For most rare marine species, abundance trends are poorly estimated. This uncertainty often translates into disagreement on management regulations, impeding conservation efforts when they are most urgently required. The world’s largest sea bream, the red steenbras Petrus rupestris, has undergone a substantial and widely acknowledged decline during the 20th century. Standardised probability of encounter over the last 3 decades was used to track red steenbras abundance trajectories in 2 regions, which together represent the species’ distribution. The results predicted a reduction in abundance of 44% in the East region and 96% in the South-West region, from what was already considered to be a collapsed population at the start of the time series. The species is now largely confined to areas in the centre of its historical abundance. Content analysis of a recreational angling magazine revealed a concurrent 50% decrease in reported size between 1984 and 2012. Shore-based observer data (2009-2010) indicate that the impact of recreational fishers on this species far exceeded that of commercial fishers at the time. Regulations in the form of progressively more stringent catch and effort restrictions appear to have been largely ineffective, too lenient, implemented too late or were unsuitable to control fishing mortality for this species. This study highlights 2 fundamental challenges in management of rare marine fish species: (1) providing decision makers with a credible measure of abundance for species whose rarity limits data availability and (2) implementing effective policy changes before the specific measures become ineffective and obsolete.
- Full Text:
- Date Issued: 2019
- Authors: Kerwath, Sven E , Parker, Denham , Winker, A Henning , Potts, Warren M , Mann, Bruce Q , Wilke, Christopher , Attwood, Colin G
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/131433 , vital:36571 , https://doi.org/10.3354/meps12853
- Description: For most rare marine species, abundance trends are poorly estimated. This uncertainty often translates into disagreement on management regulations, impeding conservation efforts when they are most urgently required. The world’s largest sea bream, the red steenbras Petrus rupestris, has undergone a substantial and widely acknowledged decline during the 20th century. Standardised probability of encounter over the last 3 decades was used to track red steenbras abundance trajectories in 2 regions, which together represent the species’ distribution. The results predicted a reduction in abundance of 44% in the East region and 96% in the South-West region, from what was already considered to be a collapsed population at the start of the time series. The species is now largely confined to areas in the centre of its historical abundance. Content analysis of a recreational angling magazine revealed a concurrent 50% decrease in reported size between 1984 and 2012. Shore-based observer data (2009-2010) indicate that the impact of recreational fishers on this species far exceeded that of commercial fishers at the time. Regulations in the form of progressively more stringent catch and effort restrictions appear to have been largely ineffective, too lenient, implemented too late or were unsuitable to control fishing mortality for this species. This study highlights 2 fundamental challenges in management of rare marine fish species: (1) providing decision makers with a credible measure of abundance for species whose rarity limits data availability and (2) implementing effective policy changes before the specific measures become ineffective and obsolete.
- Full Text:
- Date Issued: 2019
Using camera traps to generate a species inventory for medium-sized and large mammals in South West Zimbabwe:
- Welch, Rebecca J, Grant, Tanith, Parker, Daniel M
- Authors: Welch, Rebecca J , Grant, Tanith , Parker, Daniel M
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150267 , vital:38955 , https://0-doi.org.wam.seals.ac.za/10.3957/056.049.0089
- Description: We investigated the presence of medium-sized and large mammals utilizing by-catch data from a camera trapping survey in the Mangwe District in South West Zimbabwe, an unprotected commercial livestock farming area which is impacted by human encroachment, poaching and trophy hunting. The camera trapping survey was carried out from 23 October to 5 December 2009, covered an area of 200 km2 and was initially intended to estimate the population density of leopards (Panthera pardus). The study area was split into two contiguous subsections, with each section sampled for a total of 20 days using 20 cameras. Camera trap photographs were identified to species level, then compared to a list of species thought to occur in the area according to available literature, as well as sightings from professional hunters and local landowners.
- Full Text:
- Date Issued: 2019
- Authors: Welch, Rebecca J , Grant, Tanith , Parker, Daniel M
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150267 , vital:38955 , https://0-doi.org.wam.seals.ac.za/10.3957/056.049.0089
- Description: We investigated the presence of medium-sized and large mammals utilizing by-catch data from a camera trapping survey in the Mangwe District in South West Zimbabwe, an unprotected commercial livestock farming area which is impacted by human encroachment, poaching and trophy hunting. The camera trapping survey was carried out from 23 October to 5 December 2009, covered an area of 200 km2 and was initially intended to estimate the population density of leopards (Panthera pardus). The study area was split into two contiguous subsections, with each section sampled for a total of 20 days using 20 cameras. Camera trap photographs were identified to species level, then compared to a list of species thought to occur in the area according to available literature, as well as sightings from professional hunters and local landowners.
- Full Text:
- Date Issued: 2019
Virtual Activism: internet memes and political discourse in Nigeria
- Authors: Jimoh, Ganiyu A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146767 , vital:38555 , http://www.tajuniuyo.ng/Virtual Activism Internet Memes and Political Discourse in Nigeria.html
- Description: This paper examines internet memes as a unique form of narratives about political discourse in Nigeria. Through the use of social media platforms as a vehicle of political communication, internet memes about politics explore issues that contain visual metaphors aimed at provoking discourse and stimulate political participation. By employing semiotic theory, this paper examines 200 pictorial internet memes on Nigerian politics between 2015 and 2018. I argue that internet memes about politics are related to political cartoons in form and context. But unlike cartoons, memes require less artistic prowess and figurative expression in rendition but could achieve the same desire in viewers. Owing to their composition of easily digestible visual elements, they appeal to more audience who in turn could easily lend their voices to a popular meme by adding more textual or visual enhancement to create more layers of meaning.
- Full Text:
- Date Issued: 2019
- Authors: Jimoh, Ganiyu A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146767 , vital:38555 , http://www.tajuniuyo.ng/Virtual Activism Internet Memes and Political Discourse in Nigeria.html
- Description: This paper examines internet memes as a unique form of narratives about political discourse in Nigeria. Through the use of social media platforms as a vehicle of political communication, internet memes about politics explore issues that contain visual metaphors aimed at provoking discourse and stimulate political participation. By employing semiotic theory, this paper examines 200 pictorial internet memes on Nigerian politics between 2015 and 2018. I argue that internet memes about politics are related to political cartoons in form and context. But unlike cartoons, memes require less artistic prowess and figurative expression in rendition but could achieve the same desire in viewers. Owing to their composition of easily digestible visual elements, they appeal to more audience who in turn could easily lend their voices to a popular meme by adding more textual or visual enhancement to create more layers of meaning.
- Full Text:
- Date Issued: 2019
A Case Study of Two Selected Teachers as they Integrated Dynamic Geometry Software as a Visualisation Tool in Teaching Geometry:
- Mavani, Deepak, Mavani, Beena, Schäfer, Marc
- Authors: Mavani, Deepak , Mavani, Beena , Schäfer, Marc
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141076 , vital:37942 , https://doi.org/10.1080/18117295.2018.1522716
- Description: This paper reports on an aspect of a larger research study conceptualised within a teacher development project in Mthatha, Eastern Cape Province. The project was initiated with the objective to develop appropriate skills to use dynamic geometry software (DGS) effectively and strategically as a teaching and learning tool for mathematics. The study reported in this paper aims specifically to ascertain how selected mathematics teachers integrated co-developed technologically aided visualisation tools in the observed lessons. The case study involved two teachers from different schools. The data sources were the classroom observations followed by stimulated reflective interviews with the teachers. The data were analysed to study the use of DGS visualisation tools in relation to Kilpatrick’s framework of teaching proficiency.
- Full Text:
- Date Issued: 2018
- Authors: Mavani, Deepak , Mavani, Beena , Schäfer, Marc
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141076 , vital:37942 , https://doi.org/10.1080/18117295.2018.1522716
- Description: This paper reports on an aspect of a larger research study conceptualised within a teacher development project in Mthatha, Eastern Cape Province. The project was initiated with the objective to develop appropriate skills to use dynamic geometry software (DGS) effectively and strategically as a teaching and learning tool for mathematics. The study reported in this paper aims specifically to ascertain how selected mathematics teachers integrated co-developed technologically aided visualisation tools in the observed lessons. The case study involved two teachers from different schools. The data sources were the classroom observations followed by stimulated reflective interviews with the teachers. The data were analysed to study the use of DGS visualisation tools in relation to Kilpatrick’s framework of teaching proficiency.
- Full Text:
- Date Issued: 2018
An endangered seahorse selectively chooses an artificial structure
- Claassens, Louw, Booth, Anthony J, Hodgson, Alan N
- Authors: Claassens, Louw , Booth, Anthony J , Hodgson, Alan N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123718 , vital:35486 , https://doi.10.1007/s10641-018-0732-4
- Description: The development of a residential marina estate within the Knysna estuary, South Africa, introduced Reno mattresses (horizontal wire cages filled with rocks) as a novel habitat for the endangered Knysna seahorse Hippocampus capensis. Consistently high seahorse densities on these artificial structures, despite the availability of seagrass habitat, begged the question of whether this habitat was chosen by the seahorse in preference to natural vegetation. An in situ habitat choice experiment was conducted which focused on the choice made by adult H. capensis between natural vegetation (Zostera capensis) and artificial (Reno mattress) habitat within a choice chamber. Seahorses were significantly more likely to move away from Z. capensis onto a Reno mattress structure or remain on this structure. This study concludes that higher H. capensis densities on Reno mattresses within Thesen Islands Marina are owing to some positive feature of this habitat and the underlying processes responsible for the choice made by this species (additional food, holdfasts, protection) can now be investigated.
- Full Text:
- Date Issued: 2018
- Authors: Claassens, Louw , Booth, Anthony J , Hodgson, Alan N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123718 , vital:35486 , https://doi.10.1007/s10641-018-0732-4
- Description: The development of a residential marina estate within the Knysna estuary, South Africa, introduced Reno mattresses (horizontal wire cages filled with rocks) as a novel habitat for the endangered Knysna seahorse Hippocampus capensis. Consistently high seahorse densities on these artificial structures, despite the availability of seagrass habitat, begged the question of whether this habitat was chosen by the seahorse in preference to natural vegetation. An in situ habitat choice experiment was conducted which focused on the choice made by adult H. capensis between natural vegetation (Zostera capensis) and artificial (Reno mattress) habitat within a choice chamber. Seahorses were significantly more likely to move away from Z. capensis onto a Reno mattress structure or remain on this structure. This study concludes that higher H. capensis densities on Reno mattresses within Thesen Islands Marina are owing to some positive feature of this habitat and the underlying processes responsible for the choice made by this species (additional food, holdfasts, protection) can now be investigated.
- Full Text:
- Date Issued: 2018
Contrasting responses in the niches of two coral reef herbivores along a gradient of habitat disturbance in the Spermonde Archipelago, Indonesia
- Plass-Johnson, Jeremiah G, Bednarz, Vanessa N, Hill, Jaclyn M, Jompa, Jamaluddin, Ferse, Sebastian C A, Teichberg, Mirta
- Authors: Plass-Johnson, Jeremiah G , Bednarz, Vanessa N , Hill, Jaclyn M , Jompa, Jamaluddin , Ferse, Sebastian C A , Teichberg, Mirta
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69135 , vital:29398 , hhttps://doi.org/10.3389/fmars.2018.00032
- Description: Habitat modification of coral reefs is becoming increasingly common due to increases in coastal urban populations. Coral reef fish are highly dependent on benthic habitat; however, information on species-specific responses to habitat change, in particular with regard to trophic strategies, remains scarce. This study identifies variation in the trophic niches of two herbivorous coral reef fishes with contrasting trophic strategies, using Stable Isotopes Bayesian Ellipses in R, along a spatial gradient of changing coral reef habitats. In the parrotfish Chlorurus bleekeri, a roving consumer, the range of δ15N and δ13C and their niche area displayed significant relationships with the amount of rubble in the habitat. In contrast, the farming damselfish, Dischistodus prosopotaenia, showed a narrow range of both δ15N and δ13C, displaying little change in niche parameters among sites. This may indicate that parrotfish vary their feeding according to habitat, while the damselfish continue to maintain their turf and invertebrate resources. Assessing isotopic niches may help to better understand the specific trophic responses to change in the environment. Furthermore, the use of isotopic niches underlines the utility of stable isotopes in studying the potential impacts of environmental change on feeding ecology.
- Full Text:
- Date Issued: 2018
- Authors: Plass-Johnson, Jeremiah G , Bednarz, Vanessa N , Hill, Jaclyn M , Jompa, Jamaluddin , Ferse, Sebastian C A , Teichberg, Mirta
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69135 , vital:29398 , hhttps://doi.org/10.3389/fmars.2018.00032
- Description: Habitat modification of coral reefs is becoming increasingly common due to increases in coastal urban populations. Coral reef fish are highly dependent on benthic habitat; however, information on species-specific responses to habitat change, in particular with regard to trophic strategies, remains scarce. This study identifies variation in the trophic niches of two herbivorous coral reef fishes with contrasting trophic strategies, using Stable Isotopes Bayesian Ellipses in R, along a spatial gradient of changing coral reef habitats. In the parrotfish Chlorurus bleekeri, a roving consumer, the range of δ15N and δ13C and their niche area displayed significant relationships with the amount of rubble in the habitat. In contrast, the farming damselfish, Dischistodus prosopotaenia, showed a narrow range of both δ15N and δ13C, displaying little change in niche parameters among sites. This may indicate that parrotfish vary their feeding according to habitat, while the damselfish continue to maintain their turf and invertebrate resources. Assessing isotopic niches may help to better understand the specific trophic responses to change in the environment. Furthermore, the use of isotopic niches underlines the utility of stable isotopes in studying the potential impacts of environmental change on feeding ecology.
- Full Text:
- Date Issued: 2018
Developing an electromagnetic noise generator to protect a Raspberry Pi from side channel analysis
- Frieslaar, I, Irwin, Barry V W
- Authors: Frieslaar, I , Irwin, Barry V W
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429511 , vital:72618 , https://ieeexplore.ieee.org/abstract/document/8531950
- Description: This research investigates the Electromagnetic (EM) side channel leakage of a Raspberry Pi 2 B+. An evaluation is performed on the EM leakage as the device executes the AES-128 cryptographic algorithm contained in the libcrypto++ library in a threaded environment. Four multi-threaded implementations are evaluated. These implementations are Portable Operating System Interface Threads, C++11 threads, Threading Building Blocks, and OpenMP threads. It is demonstrated that the various thread techniques have distinct variations in frequency and shape as EM emanations are leaked from the Raspberry Pi. It is demonstrated that the AES-128 cryptographic implementation within the libcrypto++ library on a Raspberry Pi is vulnerable to Side Channel Analysis (SCA) attacks. The cryptographic process was seen visibly within the EM spectrum and the data for this process was extracted where digital filtering techniques was applied to the signal. The resultant data was utilised in the Differential Electromagnetic Analysis (DEMA) attack and the results revealed 16 sub-keys that are required to recover the full AES-128 secret key. Based on this discovery, this research introduced a multi-threading approach with the utilisation of Secure Hash Algorithm (SHA) to serve as a software based countermeasure to mitigate SCA attacks. The proposed countermeasure known as the FRIES noise generator executed as a Daemon and generated EM noise that was able to hide the cryptographic implementations and prevent the DEMA attack and other statistical analysis.
- Full Text:
- Date Issued: 2018
- Authors: Frieslaar, I , Irwin, Barry V W
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429511 , vital:72618 , https://ieeexplore.ieee.org/abstract/document/8531950
- Description: This research investigates the Electromagnetic (EM) side channel leakage of a Raspberry Pi 2 B+. An evaluation is performed on the EM leakage as the device executes the AES-128 cryptographic algorithm contained in the libcrypto++ library in a threaded environment. Four multi-threaded implementations are evaluated. These implementations are Portable Operating System Interface Threads, C++11 threads, Threading Building Blocks, and OpenMP threads. It is demonstrated that the various thread techniques have distinct variations in frequency and shape as EM emanations are leaked from the Raspberry Pi. It is demonstrated that the AES-128 cryptographic implementation within the libcrypto++ library on a Raspberry Pi is vulnerable to Side Channel Analysis (SCA) attacks. The cryptographic process was seen visibly within the EM spectrum and the data for this process was extracted where digital filtering techniques was applied to the signal. The resultant data was utilised in the Differential Electromagnetic Analysis (DEMA) attack and the results revealed 16 sub-keys that are required to recover the full AES-128 secret key. Based on this discovery, this research introduced a multi-threading approach with the utilisation of Secure Hash Algorithm (SHA) to serve as a software based countermeasure to mitigate SCA attacks. The proposed countermeasure known as the FRIES noise generator executed as a Daemon and generated EM noise that was able to hide the cryptographic implementations and prevent the DEMA attack and other statistical analysis.
- Full Text:
- Date Issued: 2018
Evaluating the effects of catch-and-release angling on Cape stumpnose Rhabdosargus holubi in a South African estuary
- Arkert, N K, Childs, Amber-Robyn, Parkinson, Matthew C, Winkler, Alexander C, Butler, Edward C, Mannheim, Samantha L, Potts, Warren M
- Authors: Arkert, N K , Childs, Amber-Robyn , Parkinson, Matthew C , Winkler, Alexander C , Butler, Edward C , Mannheim, Samantha L , Potts, Warren M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124439 , vital:35613 , https://doi.10.2989/1814232x.2018.1494041
- Description: Fisheries managers are increasingly promoting catch and release (C&R) as a means to manage recreational fish stocks. Several commonly used output regulations, including bag and size limits, require the mandatory release of captured fishes by anglers. In addition to mandatory C&R, conservation-conscious anglers have adopted voluntary C&R behaviour as a result of the noticeable declines in the populations of many fishery species and this behaviour is becoming increasingly popular among recreational anglers (Cooke et al. 2013a). The combination of mandatory and voluntary C&R behaviour is substantial, as Raby et al. (2014) estimated that 60% of fish captured in global recreational fisheries are released. In South Africa, Cowley et al. (2013) found that a large proportion (mean 74% [SD 7.3]) of the five most-dominant fishery species captured in the Sundays Estuary recreational fishery were released.
- Full Text:
- Date Issued: 2018
- Authors: Arkert, N K , Childs, Amber-Robyn , Parkinson, Matthew C , Winkler, Alexander C , Butler, Edward C , Mannheim, Samantha L , Potts, Warren M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124439 , vital:35613 , https://doi.10.2989/1814232x.2018.1494041
- Description: Fisheries managers are increasingly promoting catch and release (C&R) as a means to manage recreational fish stocks. Several commonly used output regulations, including bag and size limits, require the mandatory release of captured fishes by anglers. In addition to mandatory C&R, conservation-conscious anglers have adopted voluntary C&R behaviour as a result of the noticeable declines in the populations of many fishery species and this behaviour is becoming increasingly popular among recreational anglers (Cooke et al. 2013a). The combination of mandatory and voluntary C&R behaviour is substantial, as Raby et al. (2014) estimated that 60% of fish captured in global recreational fisheries are released. In South Africa, Cowley et al. (2013) found that a large proportion (mean 74% [SD 7.3]) of the five most-dominant fishery species captured in the Sundays Estuary recreational fishery were released.
- Full Text:
- Date Issued: 2018
HOP expression is regulated by p53 and RAS and characteristic of a cancer gene signature
- Mattison, Stacey A, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Mattison, Stacey A , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66278 , vital:28928 , https://doi.org/10.1007/s12192-016-0755-8
- Description: publisher version , The Hsp70/Hsp90 organising protein (HOP) is a co-chaperone essential for client protein transfer from Hsp70 to Hsp90 within the Hsp90 chaperone machine. Although HOP is upregulated in various cancers, there is limited information from in vitro studies on how HOP expression is regulated in cancer. The main objective of this study was to identify the HOP promoter and investigate its activity in cancerous cells. Bioinformatic analysis of the -2500 to +16 bp region of the HOP gene identified a large CpG island and a range of putative cis-elements. Many of the cis-elements were potentially bound by transcription factors which are activated by oncogenic pathways. Luciferase reporter assays demonstrated that the upstream region of the HOP gene contains an active promoter in vitro. Truncation of this region suggested that the core HOP promoter region was -855 to +16 bp. HOP promoter activity was highest in Hs578T, HEK293T and SV40- transformed MEF1 cell lines which expressed mutant or inactive p53. In a mutant p53 background, expression of wild-type p53 led to a reduction in promoter activity, while inhibition of wild-type p53 in HeLa cells increased HOP promoter activity. Additionally, in Hs578T and HEK293T cell lines containing inactive p53, expression of HRAS increased HOP promoter activity. However, HRAS activation of the HOP promoter was inhibited by p53 overexpression. These findings suggest for the first time that HOP expression in cancer may be regulated by both RAS activation and p53 inhibition. Taken together, these data suggest that HOP may be part of the cancer gene signature induced by a combination of mutant p53 and mutated RAS that is associated with cellular transformation.
- Full Text: false
- Date Issued: 2018
- Authors: Mattison, Stacey A , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66278 , vital:28928 , https://doi.org/10.1007/s12192-016-0755-8
- Description: publisher version , The Hsp70/Hsp90 organising protein (HOP) is a co-chaperone essential for client protein transfer from Hsp70 to Hsp90 within the Hsp90 chaperone machine. Although HOP is upregulated in various cancers, there is limited information from in vitro studies on how HOP expression is regulated in cancer. The main objective of this study was to identify the HOP promoter and investigate its activity in cancerous cells. Bioinformatic analysis of the -2500 to +16 bp region of the HOP gene identified a large CpG island and a range of putative cis-elements. Many of the cis-elements were potentially bound by transcription factors which are activated by oncogenic pathways. Luciferase reporter assays demonstrated that the upstream region of the HOP gene contains an active promoter in vitro. Truncation of this region suggested that the core HOP promoter region was -855 to +16 bp. HOP promoter activity was highest in Hs578T, HEK293T and SV40- transformed MEF1 cell lines which expressed mutant or inactive p53. In a mutant p53 background, expression of wild-type p53 led to a reduction in promoter activity, while inhibition of wild-type p53 in HeLa cells increased HOP promoter activity. Additionally, in Hs578T and HEK293T cell lines containing inactive p53, expression of HRAS increased HOP promoter activity. However, HRAS activation of the HOP promoter was inhibited by p53 overexpression. These findings suggest for the first time that HOP expression in cancer may be regulated by both RAS activation and p53 inhibition. Taken together, these data suggest that HOP may be part of the cancer gene signature induced by a combination of mutant p53 and mutated RAS that is associated with cellular transformation.
- Full Text: false
- Date Issued: 2018
Impact of invasive alien plants on water provision in selected catchments
- Preston, Ian R, Le Maitre, D C, Blignaut, J N, Louw, Lynette, Palmer, Carolyn G
- Authors: Preston, Ian R , Le Maitre, D C , Blignaut, J N , Louw, Lynette , Palmer, Carolyn G
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437979 , vital:73426 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/44_04_20_33741.pdf
- Description: We analyse the impact of failing to control invasive alien plants (IAPs) on the water supply to the Berg River and De Hoop Dams, in other words, the opportunity cost of not clearing IAPs in these two catch-ments. To do this we used models to assess and compare the impact of current and future invasions on inflows into the dams. Although the clearing of current invasions would only provide a modest increase in the amount of water compared to, for example, the construction of an-other dam, failure to clear the invasion will have a negative impact on water security in the long term. We estimated that the Berg River Dam could lose up to 51% of its mean annual inflows to IAPs over a 45-year period, and the De Hoop Dam catchment could lose up to 44%. These impacts would continue to increase over time, and the costs of control could become very high as the plants invade rugged terrain. Major in-frastructural development requires Ministerial approval, supported by advice from senior officials. We suggest that such advice should sub-stantively take sufficient account of the benefits of clearing existing in-vasions, or at least of preventing further invasions. Our results suggest that serious consequences arise from insufficient investment in catch-ment management. An integrated approach to the management of the supply of and demand for water, that ensures long-term sustainability, is essential in informed decision-making and the early control of IAPs is a key component of that approach.
- Full Text:
- Date Issued: 2018
- Authors: Preston, Ian R , Le Maitre, D C , Blignaut, J N , Louw, Lynette , Palmer, Carolyn G
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/437979 , vital:73426 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/44_04_20_33741.pdf
- Description: We analyse the impact of failing to control invasive alien plants (IAPs) on the water supply to the Berg River and De Hoop Dams, in other words, the opportunity cost of not clearing IAPs in these two catch-ments. To do this we used models to assess and compare the impact of current and future invasions on inflows into the dams. Although the clearing of current invasions would only provide a modest increase in the amount of water compared to, for example, the construction of an-other dam, failure to clear the invasion will have a negative impact on water security in the long term. We estimated that the Berg River Dam could lose up to 51% of its mean annual inflows to IAPs over a 45-year period, and the De Hoop Dam catchment could lose up to 44%. These impacts would continue to increase over time, and the costs of control could become very high as the plants invade rugged terrain. Major in-frastructural development requires Ministerial approval, supported by advice from senior officials. We suggest that such advice should sub-stantively take sufficient account of the benefits of clearing existing in-vasions, or at least of preventing further invasions. Our results suggest that serious consequences arise from insufficient investment in catch-ment management. An integrated approach to the management of the supply of and demand for water, that ensures long-term sustainability, is essential in informed decision-making and the early control of IAPs is a key component of that approach.
- Full Text:
- Date Issued: 2018
Major security incidents since 2014: an African perspective
- Van Heerden, Renier, Von Solms, Sune, Vorster, Johannes
- Authors: Van Heerden, Renier , Von Solms, Sune , Vorster, Johannes
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68291 , vital:29234 , https://ieeexplore.ieee.org/abstract/document/8417326/
- Description: Publisher version , The integration of technology in the modern society provides many benefits, but with increased connectivity comes increased risk where governments, businesses and individuals are vulnerable to a variety of cyber-attacks. Many of the large information security attacks of the last decade can be seen as an attack on 'foreign” systems or individuals when viewed from an African perspective, with no direct impact on an individual in Africa. However, information security experts in Africa states that although some of these attacks might not have had a direct impact of the African individual, but never the less should not be ignored as it does indirectly influence the African individual. The experts state that even if the individuals or businesses are not directly influenced by an attack, it should not be ignored as similar attacks might influence them in the future. They emphasise that these attacks should improve their cybersecurity awareness and behaviour, in order to prevent similar attacks from impacting them.
- Full Text: false
- Date Issued: 2018
- Authors: Van Heerden, Renier , Von Solms, Sune , Vorster, Johannes
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68291 , vital:29234 , https://ieeexplore.ieee.org/abstract/document/8417326/
- Description: Publisher version , The integration of technology in the modern society provides many benefits, but with increased connectivity comes increased risk where governments, businesses and individuals are vulnerable to a variety of cyber-attacks. Many of the large information security attacks of the last decade can be seen as an attack on 'foreign” systems or individuals when viewed from an African perspective, with no direct impact on an individual in Africa. However, information security experts in Africa states that although some of these attacks might not have had a direct impact of the African individual, but never the less should not be ignored as it does indirectly influence the African individual. The experts state that even if the individuals or businesses are not directly influenced by an attack, it should not be ignored as similar attacks might influence them in the future. They emphasise that these attacks should improve their cybersecurity awareness and behaviour, in order to prevent similar attacks from impacting them.
- Full Text: false
- Date Issued: 2018
Marine resource management and conservation in the Anthropocene
- Aswani, Shankar, Basurto, Xavier, Ferse, Sebastian, Glaser, Marion, Campbell, Lisa, Cinner, Joshua E, Dalton, Tracey, Jenkins, Lekelia D, Miller, Marc L, Pollnac, Richard, McGill University, Christie, Patrick
- Authors: Aswani, Shankar , Basurto, Xavier , Ferse, Sebastian , Glaser, Marion , Campbell, Lisa , Cinner, Joshua E , Dalton, Tracey , Jenkins, Lekelia D , Miller, Marc L , Pollnac, Richard , McGill University , Christie, Patrick
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124987 , vital:35716 , https://doi.10.1017/S0376892917000431
- Description: Because the Anthropocene by definition is an epoch during which environmental change is largely anthropogenic and driven by social, economic, psychological and political forces, environmental social scientists can effectively analyse human behaviour and knowledge systems in this context. In this subject review, we summarize key ways in which the environmental social sciences can better inform fisheries management policy and practice and marine conservation in the Anthropocene. We argue that environmental social scientists are particularly well positioned to synergize research to fill the gaps between: (1) local behaviours/needs/worldviews and marine resource management and biological conservation concerns; and (2) large-scale drivers of planetary environmental change (globalization, affluence, technological change, etc.) and local cognitive, socioeconomic, cultural and historical processes that shape human behaviour in the marine environment. To illustrate this, we synthesize the roles of various environmental social science disciplines in better understanding the interaction between humans and tropical marine ecosystems in developing nations where issues arising from human–coastal interactions are particularly pronounced. We focus on: (1) the application of the environmental social sciences in marine resource management and conservation; (2) the development of ‘new’ socially equitable marine conservation; (3) repopulating the seascape; (4) incorporating multi-scale dynamics of marine social–ecological systems; and (5) envisioning the future of marine resource management and conservation for producing policies and projects for comprehensive and successful resource management and conservation in the Anthropocene.
- Full Text:
- Date Issued: 2018
- Authors: Aswani, Shankar , Basurto, Xavier , Ferse, Sebastian , Glaser, Marion , Campbell, Lisa , Cinner, Joshua E , Dalton, Tracey , Jenkins, Lekelia D , Miller, Marc L , Pollnac, Richard , McGill University , Christie, Patrick
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124987 , vital:35716 , https://doi.10.1017/S0376892917000431
- Description: Because the Anthropocene by definition is an epoch during which environmental change is largely anthropogenic and driven by social, economic, psychological and political forces, environmental social scientists can effectively analyse human behaviour and knowledge systems in this context. In this subject review, we summarize key ways in which the environmental social sciences can better inform fisheries management policy and practice and marine conservation in the Anthropocene. We argue that environmental social scientists are particularly well positioned to synergize research to fill the gaps between: (1) local behaviours/needs/worldviews and marine resource management and biological conservation concerns; and (2) large-scale drivers of planetary environmental change (globalization, affluence, technological change, etc.) and local cognitive, socioeconomic, cultural and historical processes that shape human behaviour in the marine environment. To illustrate this, we synthesize the roles of various environmental social science disciplines in better understanding the interaction between humans and tropical marine ecosystems in developing nations where issues arising from human–coastal interactions are particularly pronounced. We focus on: (1) the application of the environmental social sciences in marine resource management and conservation; (2) the development of ‘new’ socially equitable marine conservation; (3) repopulating the seascape; (4) incorporating multi-scale dynamics of marine social–ecological systems; and (5) envisioning the future of marine resource management and conservation for producing policies and projects for comprehensive and successful resource management and conservation in the Anthropocene.
- Full Text:
- Date Issued: 2018
Rinistachya hilleri gen. et sp. nov.(Sphenophyllales), from the upper Devonian of South Africa
- Prestianni, Cyrille, Gess, Robert W
- Authors: Prestianni, Cyrille , Gess, Robert W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73883 , vital:30238 , https://doi.org/10.1007/s13127-018-0385-3
- Description: A rich and diverse plant assemblage has been excavated from latest Devonian (Famennian) black shales of the Witpoort Formation (Witteberg Group) at Waterloo Farm, close to the city of Grahamstown (South Africa). Several specimens of a new sphenopsid have been collected. The description of this as a new taxon, here named Rinistachya hilleri, gen. et sp. nov., provides an important addition to the scarce early record of the group. Rinistachya hilleri presents a novel architecture that include apparently plesiomorphic characters, reminiscent of the organisation of the Iridopteridales (including the production of two types of laterals at one node, the location of fertile parts in loose whorls on lateral branches and an organisation of the fertile parts in which they branch several times before bearing distally elongate sporangia). Other characters unambiguously nest Rinistachya within the Sphenopsida (including presence of planate and slightly webbed ultimate appendages and lateral strobili made of successive whorls of fertile leaves with fertile parts located at their axil). This provides strong support for a close relationship between Sphenopsida and Iridopteridales. Rinistachya furthermore represents the first record of a Devonian sphenopsid from Gondwana and extends the known distribution of the Sphenopsida from the tropics to very high palaeolatitudes. It is a new sphenopsid with a peculiar organisation. The new taxon allows better characterization of the initial evolutionary radiation at the base of the group.
- Full Text:
- Date Issued: 2018
- Authors: Prestianni, Cyrille , Gess, Robert W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73883 , vital:30238 , https://doi.org/10.1007/s13127-018-0385-3
- Description: A rich and diverse plant assemblage has been excavated from latest Devonian (Famennian) black shales of the Witpoort Formation (Witteberg Group) at Waterloo Farm, close to the city of Grahamstown (South Africa). Several specimens of a new sphenopsid have been collected. The description of this as a new taxon, here named Rinistachya hilleri, gen. et sp. nov., provides an important addition to the scarce early record of the group. Rinistachya hilleri presents a novel architecture that include apparently plesiomorphic characters, reminiscent of the organisation of the Iridopteridales (including the production of two types of laterals at one node, the location of fertile parts in loose whorls on lateral branches and an organisation of the fertile parts in which they branch several times before bearing distally elongate sporangia). Other characters unambiguously nest Rinistachya within the Sphenopsida (including presence of planate and slightly webbed ultimate appendages and lateral strobili made of successive whorls of fertile leaves with fertile parts located at their axil). This provides strong support for a close relationship between Sphenopsida and Iridopteridales. Rinistachya furthermore represents the first record of a Devonian sphenopsid from Gondwana and extends the known distribution of the Sphenopsida from the tropics to very high palaeolatitudes. It is a new sphenopsid with a peculiar organisation. The new taxon allows better characterization of the initial evolutionary radiation at the base of the group.
- Full Text:
- Date Issued: 2018