3,258 research outputs found
Approaching the Hartree-Fock Limit Through the CABS Singles Correction and Auxiliary Basis Sets
Auxiliary basis sets for use in the resolution of the identity (RI) approximation in explicitly correlated methods are presented for the elements HâAr. These extend the cc-pVnZ-F12/OptRI (n = DâQ) auxiliary basis sets of Peterson and coworkers by the addition of a small number of s- and p-functions, optimized so as to yield the great- est complementary auxiliary basis set (CABS) singles correction to the Hartree-Fock energy. The new sets, denoted OptRI+, also lead to a reduction in errors due to the RI approximation and hence an improvement in correlation energies. The atomization energies and heats of formation for a test set of small molecules, and spectroscopic constants for 27 diatomics, calculated at the CCSD(T)-F12b level, are shown to have improved error distributions for the new auxiliary basis sets with negligible additional effort. The OptRI+ sets retain all of the desirable properties of the original OptRI, including the production of smooth potential energy surfaces, whilst maintaining a compact nature
Biogeographic Variation in the Diet and Behaviour of Cercopithecus mitis
Primate species are characterised by variation in foraging behaviour and dietary composition across their geographic range. Here we examine how ecological conditions account for variation in the behavioural ecology of a widespread arboreal guenon, Cercopithecus mitis. Although substantial variation existed in time budgets, group size, home range and day journey length, clear biogeographic patterns were not apparent. In contrast, dietary variation was correlated with underlying climatic conditions. Temperature seasonality, which tends to increase with latitude, was significantly positively related to the proportion of fruit in the diet and negatively related to the proportion of animal matter. Both dietary components were âpreferred' foods, with the variability between populations reflecting the availability of different food types across their geographic range. Although we found no significant relationships between climate and the proportion of leaves in the diet, the ability for C. mitis to vary its diet to include a diversity of food types, and to incorporate a significant proportion of leaves when preferred sources are scarce, likely underpins its ability to survive across such a large distribution
Field guarding as a crop protection method: Preliminary implications for improving field guarding
Negative interactions between crop farmers and wild primates are an issue of significant concern. Despite many crop farmers using field guards as a method of crop protection against foraging primates, there are very few published accounts of how effective this technique is and how it might be improved. To bridge this knowledge gap, we used direct observations from a hide to collect the behaviors of field guards, chacma baboons (Papio ursinus; baboons), and vervet monkeys (Chlorocebus pygerythrus; vervets) foraging in a 1-ha butternut squash (Cucurbita moschata) field for 4 months (May to August) in 2013 on a 564-ha commercial farm in the Blouberg District of South Africa. Only half of the crop-foraging events were chased by field guards, with vervets being chased much less frequently than baboons. Guards responded more often to events with greater primate numbers and to those that occurred earlier in the day. Guard delay in responding to crop-foraging events and baboon delay in responding to the guard both increased in the low productivity season. Baboon response delay also increased with more animals involved. Based on this case study, we suggest recommendations to improve the effectiveness of field guarding. This includes implementing an early warning alarm system, shortening field guard shifts, increasing guard numbers during the morning and low productivity season, and increasing the perceived fear of field guards, potentially by employing male guards or providing uniforms and deterrent accessories. Further evaluation in other local contexts will help determine how these findings can be adopted on a wider scale
What have we been looking at? A call for consistency in studies of primate vigilance
Vigilance functions to detect threats. In primates, these threats emerge from both predators and conspecifics, but a host of other social, demographic, and ecological factors have been shown to influence primate vigilance patterns. The primate vigilance literature is thus characterized by considerable variation in findings, with inconsistent or contradictory results reported not only across different species but also within species and populations across studies. Some of this variation could emerge from fundamental differences in the methods employed, making comparisons across species and groups challenging. Furthermore, identifying consistent behavioral markers for the state of vigilance appears to have proved challenging in primates, leading to a range of definitions being developed. Deviation at this level leads directly into concomitant variation at the level of sampling methodologies. As a result, the primate vigilance literature currently presents a diverse series of approaches to exploring subtly different behaviors and phenomena. This review calls for a greater consistency in studying vigilance, with the aim of encouraging future research to follow similar principles leading to more comparable results. Identifying whether an animal is in a vigilant state is challenging for most field researchers; identifying and recording a more general behavior of âlookingâ should though be more achievable. Experimental approaches could then be employed to understand the compatibility âlookingâ has with predator detection (and other threats) in individual study systems. The outcome of this approach will allow researchers to understand the key determinants of looking in their study groups and explore threat detection probabilities given an individual or group's relative level of looking
Risk adjustment for hospital use using social security data: cross sectional small area analysis
OBJECTIVES: To identify demographic and socioeconomic determinants of need for acute hospital treatment at small area level. To establish whether there is a relation between poverty and use of inpatient services. To devise a risk adjustment formula for distributing public funds for hospital services using, as far as possible, variables that can be updated between censuses. DESIGN: Cross sectional analysis. Spatial interactive modelling was used to quantify the proximity of the population to health service facilities. Two stage weighted least squares regression was used to model use against supply of hospital and community services and a wide range of potential needs drivers including health, socioeconomic census variables, uptake of income support and family credit, and religious denomination. SETTING: Northern Ireland. MAIN OUTCOME MEASURE: Intensity of use of inpatient services. RESULTS: After endogeneity of supply and use was taken into account, a statistical model was produced that predicted use based on five variables: income support, family credit, elderly people living alone, all ages standardised mortality ratio, and low birth weight. The main effect of the formula produced is to move resources from urban to rural areas. CONCLUSIONS: This work has produced a population risk adjustment formula for acute hospital treatment in which four of the five variables can be updated annually rather than relying on census derived data. Inclusion of the social security data makes a substantial difference to the model and to the results produced by the formula
Nonlocality and entanglement in a strange system
We show that the relation between nonlocality and entanglement is subtler
than one naively expects. In order to do this we consider the neutral kaon
system--which is oscillating in time (particle--antiparticle mixing) and
decaying--and describe it as an open quantum system. We consider a Bell--CHSH
inequality and show a novel violation for non--maximally entangled states.
Considering the change of purity and entanglement in time we find that, despite
the fact that only two degrees of freedom at a certain time can be measured,
the neutral kaon system does not behave like a bipartite qubit system.Comment: 7 pages, 2 figures, extended versio
Habituation is not neutral or equal: Individual differences in tolerance suggest an overlooked personality trait
In behavioral studies, observer effects can be substantial, even for habituated animals, but few studies account for potential observer-related phenomenon empirically. We used wild, habituated chacma baboons to explore two key assumptions of behavioral ecology (i) that observers become a âneutralâ stimulus and (ii) that habituation is âequalâ across group members. Using flight initiation distance (FID) methods within a personality paradigm, the behavioral responses of baboons suggested that observers were not perceived as neutral but instead viewed as a high-ranking social threat. Habituation was also not equal across group members, with repeatable individual differences more important than contextual factors (e.g., habitat) in determining the distance at which baboons visually oriented or displaced from observers. A strong correlation between individual visual tolerance and displacement tolerance (i.e., convergent validity) indicated a personality trait. We offer several suggestions for how to account for these factors and minimize potential bias in future studies
Reliance on exotic plants by two groups of threatened samango monkeys, Cercopithecus albogularis labiatus, at their southern range limit
Understanding how threatened species adapt their behavior to landscapes shaped by humans is increasingly important to ensuring they persist in a changing world. Matrix habitats can be shared spaces where human and nonhuman primates coexist. We set out to determine how an endemic, threatened forest specialist, the frugivorous, arboreal samango monkey (Cercopithecus albogularis labiatus), has responded to a matrix habitat made up of residential gardens and commercial plantations in Eastern Cape province, South Africa. We followed two groups from dawn to dusk for a mean of 3 days/mo for 12 mo (February 1, 2011 to January 31, 2012) using scan sampling to collect data on their diet, activity, and ranging patterns. We used resource abundance transects to describe the groupsâ home ranges and monitored tree phenology to calculate fruit and seed availability indices. Monkeys from both groups consumed large quantities of exotic plant species, accounting for >50% of their overall annual diet, with seeds of the invasive black wattle (Acacia mearnsii) the most commonly consumed exotic species followed by acorns of two oak species (Quercus robur and Q. palustris.). However, monkeys responded to the availability of indigenous rather than exotic fruits and seeds and increased their consumption of exotics when indigenous fruits were less available. Although monkeys spent less time moving when feeding on exotic species compared to indigenous species, eating exotics did not free up monkeysâ time to rest or socialize, as additional time was required to process exotic foods. To offset the possible negative consequences of the monkeysâ reliance on exotic seeds, including escalating conflict between monkeys and people in gardens, we suggest gradual removal of exotic plant species in the habitat and replacement with indigenous species as one mitigation strategy
Intolerant baboons avoid observer proximity, creating biased inter-individual association patterns
Social network analysis is an increasingly popular tool for behavioural ecologists exploring the social organisation of animal populations. Such analyses require data on inter-individual association patterns, which in wild populations are often collected using direct observations of habituated animals. This assumes observers have no influence on animal behaviour; however, our previous work showed that individuals in a habituated group of chacma baboons (Papio ursinus griseipes) displayed consistent and individually distinct responses to observer approaches. We explored the implications of our previous findings by measuring the inter-individual association patterns of the same group of chacma baboons at different observer distances. We found a strong positive association between individual tolerance levels (towards observers) and how often an animal appeared as a neighbour to focal animals when observers were nearer, and a neutral relationship between the same variables when the observer was further away. Additionally, association matrices constructed from different observation distances were not comparable within any proximity buffer, and neither were the individual network metrics generated from these matrices. This appears to be the first empirical evidence that observer presence and behaviour can influence the association patterns of habituated animals and thus have potentially significant impacts on measured social networks
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