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Bridgestone South Africa; De Beers Group of Companies; E. Oppenheimer and Son; Endangered Wildlife Trust.

The locomotor activity patterns of two species of shrew were investigated under both standard laboratory conditions and in their natural environment. Trapping, using live traps, was undertaken on a seasonal basis to determine the predominant periods of activity for each species in their natural habitat. We assessed if there was a seasonal variation to the locomotor activity in the shrews. In the laboratory, locomotor activity patterns were investigated under the following lighting conditions, in sequence; 12L:12D (2 weeks), constant darkness (3 weeks), 12L:12D (2 weeks), 12D:12L an inverted light cycle (2 weeks) followed by 6 weeks at 16L:8D and 8L:16D for each species. Temperature was maintained at a constant temperature of 25 ± 1°C. Foraging behaviour and body mass changes were recorded throughout the study. Both species exhibited predominantly nocturnal locomotory activity patterns under laboratory conditions. In the field the forest shrew, Myosorex varius, altered its predominant activity period depending on the season, displayed polyphasic activity patterns and was caught throughout the year; it neither gained nor lost body mass. The greater red musk shrew, Crocidura flavescens, was strictly nocturnal in the field, more so than under laboratory conditions, gained body mass readily in the laboratory and was very rarely captured during winter. Therefore, each species displayed slightly different behavioural adaptations when exposed to the same conditions. These findings emphasize the similarities and differences in activity amongst co-occurring small mammal species in light of possible competition avoidance mechanisms.

Many studies have shown that memory retrieval for real-time language processing relies on a cue-based access mechanism, which allows the cues available at the retrieval site to directly access the target representation in memory. An open question is how different types of cues are combined at retrieval to create a single retrieval probe ("cue combinatorics"). This study addresses this question by testing whether retrieval for antecedent-reflexive dependencies combines cues in a linear (i.e., additive) or nonlinear (i.e., multiplicative) fashion. Results from computational simulations and a reading time experiment show that target items that match all the cues of the reflexive are favored more than target items that mismatch these cues, and that different degrees of mismatches slow reading times in comparable amounts. This profile is consistent with the predictions of a nonlinear cue combination and provides evidence against models in which all cues combine in a linear fashion. A follow-up set of simulations shows that a nonlinear rule also captures previous demonstrations of interference from nontarget items during retrieval for reflexive licensing. Taken together, these results shed new light on how different types of cues combine at the retrieval site and reveal how the method of cue combination impacts the accessibility of linguistic information in memory.

This paper presents a computational model that integrates a dynamically structured holographic memory system into the ACT-R cognitive architecture to explain how linguistic representations are encoded and accessed in memory. ACT-R currently serves as the most precise expression of the moment-by-moment working memory retrievals that support sentence comprehension. The ACT-R model of sentence comprehension is able to capture a range of linguistic phenomena, but there are cases where the model makes the wrong predictions, such as the over-prediction of retrieval interference effects during sentence comprehension. Here, we investigate one such case involving the processing of sentences with negative polarity items (NPIs) and consider how a dynamically structured holographic memory system might provide a cognitively plausible and principled explanation of some previously unexplained effects. Specifically, we show that by replacing ACT-R's declarative memory with a dynamically structured memory, we can explain a wider range of behavioral data involving reading times and judgments of grammaticality. We show that our integrated model provides a better fit to human error rates and response latencies than the original ACT-R model. These results provide proof-of-concept for the unification of two independent computational cognitive frameworks.

Over the past 50 years, Plasmodium falciparum has developed resistance against all antimalarial drugs used against it: chloroquine, sulphadoxine-pyrimethamine, quinine, piperaquine and mefloquine. More recently, resistance to the artemisinin derivatives and the resulting failure of artemisinin-based combination therapy (ACT) are threatening all major gains made in malaria control. Each time resistance has developed progressively, with delayed clearance of parasites first emerging only in a few regions, increasing in prevalence and geographic range, and then ultimately resulting in the complete failure of that antimalarial. Drawing from this repeated historical chain of events, this article presents context-specific approaches for combating drug-resistant P. falciparum malaria. The approaches begin with a context of drug-sensitive parasites and focus on the prevention of the emergence of drug resistance. Next, the approaches address a scenario in which resistance has emerged and is increasing in prevalence and geographic extent, with interventions focused on disrupting transmission through vector control, early diagnosis and treatment, and the use of new combination therapies. Elimination is also presented as an approach for addressing the imminent failure of all available antimalarials. The final drug resistance context presented is one in which all available antimalarials have failed; leaving only personal protection and the use of new antimalarials (or new combinations of antimalarials) as a viable strategy for dealing with complete resistance. All effective strategies and contexts require a multipronged, holistic approach.

Previous assessments of wildlife road mortality have not used directly comparable methods and, at present, there is no standardized protocol for the collection of such data. Consequently, there are no internationally comparative statistics documenting roadkill rates. In this study, we used a combination of experimental trials and road transects to design a standardized protocol to assess roadkill rates on both paved and unpaved roads. Simulated roadkill were positioned over a 1 km distance, and trials were conducted at eight different speeds (20-100 km·h(-1)). The recommended protocol was then tested on a 100-km transect, driven daily over a 40-day period. This recorded 413 vertebrate roadkill, comprising 106 species. We recommend the protocol be adopted for future road ecology studies to enable robust statistical comparisons between studies.

Lysine acetylation has emerged as a major post-translational modification involved in diverse cellular functions. Using a combination of immunoisolation and liquid chromatography coupled to accurate mass spectrometry, we determined the first acetylome of the human malaria parasite Plasmodium falciparum during its active proliferation in erythrocytes with 421 acetylation sites identified in 230 proteins. Lysine-acetylated proteins are distributed in the nucleus, cytoplasm, mitochondrion and apicoplast. Whereas occurrence of lysine acetylation in a similarly wide range of cellular functions suggests conservation of lysine acetylation through evolution, the Plasmodium acetylome also revealed significant divergence from those of other eukaryotes and even the closely related parasite Toxoplasma. This divergence is reflected in the acetylation of a large number of Plasmodium-specific proteins and different acetylation sites in evolutionarily conserved acetylated proteins. A prominent example is the abundant acetylation of proteins in the glycolysis pathway but relatively deficient acetylation of enzymes in the citrate cycle. Using specific transgenic lines and inhibitors, we determined that the acetyltransferase PfMYST and lysine deacetylases play important roles in regulating the dynamics of cytoplasmic protein acetylation. The Plasmodium acetylome provides an exciting start point for further exploration of functions of acetylation in the biology of malaria parasites.

The mesopredator release hypothesis states that when middle-ranked predators are freed from the top-down control of apex predators, their populations will increase and predation pressure on certain prey species intensifies (Prugh et al., 2009). Examples include the release of coyotes (Canis latrans, Say 1823) following the extirpation of wolves (Canis lupus, L. 1758) in Wyoming, USA (Berger & Conner, 2008) and the suppressing effect of dingoes (Canis lupus dingo, Meyer 1793) on red fox (Vulpes vulpes, L. 1758) populations in eastern Australia (Johnson & Vanderwal, 2009). The hypothesis may provide a theoretical framework to explain the overall success of black-backed jackals (Canis mesomelas, Schreber 1775) in South Africa (Loveridge & Nel, 2004), following the extirpation of large (apex) predators, such as lions (Panthera leo, L. 1758), from many parts of their range, in the early twentieth century (Crooks & Soule, 1999). However, the increased potential for earning foreign income from trophy hunting and ⁄ or ecotourism has seen a significant change in the land use of the Eastern Cape of South Africa (Smith & Wilson, 2002). Many agrarian properties have been converted into game farms and wildlife reserves (Smith & Wilson, 2002), and large predators have been reintroduced to attract tourists (Hayward et al., 2007). The reintroduction of superior predators to game reserves may therefore reinstate top-down forcing in these systems (Estes et al., 2011), resulting in mesopredator suppression effects, such as spatial avoidance and behavioural suppression via altered activity patterns and dietary avoidance (Hayward & Kerley, 2008; Hayward & Slotow, 2009; Van Der Merwe et al., 2009). The objective of this study was to compare the dietary composition of two black-backed jackal populations; one with large predators present and one without.

Studies concerning the influence of African elephants (Loxodonta africana) on vegetation have produced contradictory results; some show minimal or no effect while others report significant elephant-induced effects. Elephants are generalist megaherbivores but will selectively feed from preferred plant species. We investigated the mortality of aloe plants (highly preferred food items for elephants) at five sites with elephants (treatment) and five paired sites without elephants (control) in the Eastern Cape Province of South Africa. A significantly higher proportion of aloes were dead at treatment sites and significantly more aloes that had lost their crown (headless) were found at treatment sites compared with controls. We conclude that although the proportions of dead aloes at treatment sites were significantly higher, it remains unclear whether there is a need to be concerned with the potential small-scale extinction of aloes from parts of the Eastern Cape Province. The observed mortality may merely be an artefact of the loss of large herbivores through disease (e.g. rinderpest) and hunting in the past. Resume Des etudes de l’influence des elephants africains (Loxodonta africana) sur la vegetation ont produit des resultats contradictoires: certaines montrent un effet minimal, voire nul, alors que d’autres signalent des effets significatifs. Les elephants sont des grands herbivores generalistes, mais ils se nourrissent selectivement de certaines parties des plantes. Nous avons etudie la mortalite de plants d’aloes (nourriture fortement privilegiee par les elephants) a cinq sites avec elephants (traitement) et a cinq autres sites sans elephant (temoins), dans la Province du Cap oriental, en Afrique du Sud. Il y avait une proportion significativement plus grande d’aloes morts dans les sites du traitement, et ils etaient significativement plus nombreux a avoir perdu leur couronne (etetes) que dans les sites temoins. Nous concluons que, bien que la proportion d’aloes morts soit significativement plus grande dans les sites du traitement, il n’est pas evident de savoir s’il faut s’inquieter de cette possible extinction a petite echelle des aloes dans certaines parties de la Province du Cap oriental. La mortalite observee peut bien etre simplement un artefact de la perte des grands herbivores en raison de maladies (ex. la peste bovine) et de la chasse dans le passe.

Diet assessment of herbivores provides insight into trophic relationships, the potential for competition, and the influences herbivores may have on an ecosystem (Bookhout 1996). Thus, the determination of their food requirements is imperative prior to the implementation of any management decisions, which must be based on reliable data (Bookhout 1996). Direct observations and fecal analysis are 2 commonly employed techniques for assessing the diet of wild herbivores (Van Aarde and Skinner 1975, Field and Ross 1976, McInnes et al. 1983, Landman and Kerley 2001, Parker et al. 2003). However, both methods are biased in the way in which they quantify herbivore diets (for review see: Dearden et al. 1975, McInnes et al. 1983, Norbury and Sanson 1992, Bookhout 1996). Traditionally, the diet of megaherbivores (herbivores that exceed 1,000 kg; Owen-Smith 1992) was quantified using direct observations because megaherbivores are conspicuous and easy to observe compared to smaller, more cryptic ungulates. The giraffe (Giraffa camelopardalis) is no exception (Leuthold and Leuthold 1972, Van Aarde and Skinner 1975, Parker et al. 2003). They are large, browsing ruminants (Owen-Smith 1992) that favor open or broken savanna habitats (Skinner and Smithers 1990) and browse exclusively on woody vegetation (Owen-Smith 1992). Giraffes are highly selective compared to other megaherbivores due to their unique foraging technique, whereby they strip the leaves off the terminal shoots of trees with their long tongue (Cooper and Owen-Smith 1986, Owen-Smith 1992). Typically, trees from the genus Acacia are the mainstay of giraffe diet (Du Toit et al. 1990). However, most Acacia species are deciduous and lose their leaves during the dry or cold season (Parker et al. 2003). Consequently, giraffes include a greater proportion of evergreen or semi-deciduous vegetation in their diet during this period (Sauer 1983, Parker et al. 2003). Apart from males having higher forage intake rates than females (Ginnett and Demment 1997), no sex differences in diet composition have been reported in the literature. We compared direct observations and fecal analysis to determine the diet of a megaherbivore on a regional scale, using the giraffe as a model. We tested the ability of the 2 methods to detect the most important plant species and the seasonal changes in the diet. There is no a priori reason to suggest that one method will perform better than the other, and we predicted that it is most likely that the 2 methods together will give the most robust results.

With an increase in the popularity of wildlife ranching in southern Africa has come the introduction of non-native (extralimital) mammalian herbivores. Financial gain has arguably been at the forefront of these introductions, with little or no assessment of the ecological consequences. The diet of three populations of introduced giraffe Giraffa camelopardalis was assessed by direct observation in the Eastern Cape Province, South Africa between January 2002 and October 2003, as the first step towards understanding the ecological role played by giraffe in the region. Similar to the diet of giraffe within their native range, a deciduous species from the genus Acacia (Acacia karroo) was the most important species in the diet. Giraffe in the Eastern Cape Province, however, consumed more evergreen species than those within their native range. The relative lack of deciduous species in the Eastern Cape Province provides a probable explanation for such a result. Seasonal variation in the consumption of the most important species in the diet was evident with members of the genus Rhus being more important in the winter months. This was attributed to the deciduous nature of A. karroo. The potential for giraffe to have a detrimental effect on the indigenous vegetation is discussed. We conclude that the study provides a much-needed list of plant species threatened by giraffe browsing in a region where the vegetation is thought to have evolved in the absence of such a browser.

Giraffe are extralimital in the Eastern Cape Province, South Africa where recent local introductions have persisted despite limited research into their impact on the indigenous flora. The diet of 15 giraffe at the Shamwari Game Reserve was recorded by direct observation during summer (March/April) and winter (July/August) 2001, quantifying diet by frequency of occurrence (individual records scored and expressed as a percentage of the total). Preference indices were also calculated. Habitat use was measured by the number of hours giraffe fed in different habitats. The diet comprised of 14 plant species, the most important species being Rhus longispina (47.9%), Acacia karroo (25.7%) and Euclea undulata (17.6%). Importance of R. longispina, A. karroo and Tarchonanthus camphoratus fluctuated seasonally. Rhus longispina was more important in winter with a corresponding decrease in feeding on A. karroo. Tarchonanthus camphoratus was only consumed during summer. Acacia karroo thickets (previously disturbed areas) were utilized most (summer 12 h; winter 9 h), with alternative habitats utilized more often in winter than in summer. We suggest that the seasonal fluctuation in the importance of R. longispina & A. karroo reflects the deciduous nature of A. karroo. Resume Des girafes vivent en dehors des limites de leur aire de repartition dans la Province Orientale du Cap, en Afrique du Sud, ou de recentes introductions locales se sont poursuivies malgre le manque de recherche sur leur impact sur la flore indigene. On a releve le regime alimentaire de 15 girafes de la Reserve de Faune de Shamwari par des observations directes en ete (mars-avril) et en hiver (juillet-aout) 2001, en le quantifiant au moyen de la frequence de l'occurrence (resultats individuels exprimes en pourcentage du total). On a aussi calcule les indices de preference. L'utilisation de l'habitat a ete mesuree au moyen du nombre d'heures que les girafes passaient a se nourrir dans les differents habitats. Le menu comprenait 14 especes de plantes dont les plus importantes sont Rhus longispina (47.9%), Acacia karroo (25.7%) et Euclea undulata (17.6%). L'importance de R. longispina, A. karroo et Tarchonanthus camphoratus fluctuait avec les saisons. Rhus longispinaetait plus important en hiver, ce qui correspondait a une diminution de l'absorption d'A. karroo. Tarchonanthus camphoratus n'etait consomme qu'en ete. Les buissons d'Acacia karroo (les zones anciennement perturbees) etaient les plus utilises (12 heures en ete, 9 h. en hiver) avec des habitats alternatifs, plus utilises en hiver qu'en ete. Nous suggerons que la fluctuation saisonniere de l'importance de R. longispina et d'A. karroo reflete la nature decidue de ce dernier.