298 research outputs found
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Long-term inter-sexual association patterns among wild chimpanzees
The widely accepted socio-ecological model of primate sociality assumes that males and female chimpanzees do not exhibit differentiated social relationships. However, despite anecdotal evidence to the contrary, this assumption has never been explicitly tested. We used 14 years of data from the Kanyawara community in Kibale National Park, Uganda to describe inter-sexual association patterns among these chimpanzees. We calculated a composite index using temporal and spatial association data to characterize the relationships between data to characterize the relationships between 336 male-females dyads. We considered any dyad with a composite index greater than one standard deviation above the mean to be strongly associated. We found that: (1) while the majority of male-female dyads were not strongly associated, a subset of dyads showed greater than average association across several two-year time periods; (2) all but one of the maternal kin dyads (either mother-son or brother-sister) had differentiated relationships; and (3) the association preferences of some dyads remained consistent despite changes in the reproductive condition of the female over time. We used generalized linear models to determine the effect of reproductive state, rank and seasonality on patterning these long-term associations. Our finding that chimpanzees exhibit differentiated inter-sexual association patterns will have far-reaching effects on studies of other forms of male-female interaction such as aggression, and further our understanding of the evolution of human pair-bonding.AnthropologyHuman Evolutionary Biolog
Development of forest structure and leaf area in secondary forests regenerating on abandoned pastures in Central Amazonia
The area of secondary forest (SF) regenerating from pastures is increasing in the Amazon basin; however, the return of forest and canopy structure following abandonment is not well understood. This study examined the development of leaf area index (LAI), canopy cover, aboveground biomass, stem density, diameter at breast height (DBH), and basal area ( BA) by growth form and diameter class for 10 SFs regenerating from abandoned pastures. Biomass accrual was tree dominated, constituting >= 94% of the total measured biomass in all forests abandoned >= 4 to 6 yr. Vine biomass increased with forest age, but its relative contribution to total biomass decreased with time. The forests were dominated by the tree Vismia spp. (> 50%). Tree stem density peaked after 6 to 8 yr ( 10 320 stems per hectare) before declining by 42% in the 12- to 14-yr-old SFs. Small-diameter tree stems in the 1-5-cm size class composed > 58% of the total stems for all forests. After 12 to 14 yr, there was no significant leaf area below 150-cm height. Leaf area return (LAI = 3.2 after 12 to 14 yr) relative to biomass was slower than literature-reported recovery following slash-and-burn, where LAI can reach primary forest levels ( LAI = 4 - 6) in 5 yr. After 12 to 14 yr, the colonizing vegetation returned some components of forest structure to values reported for primary forest. Basal area and LAI were 50% - 60%, canopy cover and stem density were nearly 100%, and the rapid tree-dominated biomass accrual was 25% - 50% of values reported for primary forest. Biomass accumulation may reach an asymptote earlier than expected because of even-aged, monospecific, untiered stand structure. The very slow leaf area accumulation relative to biomass and to reported values for recovery following slash-and-burn indicates a different canopy development pathway that warrants further investigation of causes ( e. g., nutrient limitations, competition) and effects on processes such as evapotranspiration and soil water uptake, which would influence long-term recovery rates and have regional implications
Correlation but no causation between leaf nitrogen and maximum assimilation: the role of drought and reproduction in gas exchange in an understory tropical plant Miconia ciliata (Melastomataceae).
Alternative hypotheses were tested to explain a previously reported anomaly in the response of leaf photosynthetic capacity at light saturation (A..) in Miconia ciliata to dry-season irrigation. The anomaly is characterized by an abrupt increase in leaf A._ for nonirrigated plants at the onset of the rainy season to values that significantly exceeded corresponding measurements for plants that were irrigated during the previous dry season. Hypothesis I posits that a pulse in leaf nitrogen increases CO2 assimilation in nonirrigated plants at the onset of the wet season and is dampened for irrigated plants; this hypothesis was rejected because, although a wet-season nitrogen pulse did occur, it was identical for both irrigated and nonirrigated plants and was preceded by the increase in assimilation by nonirrigated plants. Hypothesis 2 posits that a reproduction-related, compensatory photosynthetic response occurs in nonirrigated plants following the onset of the wet season and is dampened in irrigated plants; consistent with hypothesis 2, high maximum assimilation rates for control plants in the wet season were significantly correlated with fruiting and flowering, whereas irrigation caused flowering and fruiting in the dry season, spreading M. ciliata reproductive activity in irrigated plants across the entire year
Comparative study between biological and chemical agents for control sheath blight disease of rice
Biological control measures are indispensable to sustain global food security, due to it being economically profitable and environmentally sound. A comparative study was conducted to know the effectiveness of biological control measures compared with contact fungicide. Trichoderma spp. based bio fungicides Bioquick and Biospark were applied as preventive measures and contact fungicide as a curative measure for controlling sheath blight disease in rice varieties BR 71 and IR 24. Biospark and Bioquick were applied before disease development while, contact fungicide was used after the initiation of sheath blight disease. At the early stage of disease development, the effect of Bioquick, Biospark, and fungicide in terms of reducing percent relative lesion height and percent tiller infection are comparable. At 14 DAI and 18 DAI, contact fungicide performed best among the three control measures based on the two parameters. The genotypes of the rice accessions used in the study also appeared to be a factor in disease development, as evidenced by higher horizontal and vertical disease severity in BR71 than in IR24. Between comparison of Bioquick and Biospark in terms of reducing percent relative lesion height, percent tiller infection, and percent disease control, appeared to be higher in Biospark in both varieties. From this study, we can conclude that farmers can use Biospark as a biofungicide to get maximum benefit considering rice yield and ecology. However, its efficacy is slightly lower than chemical fungicides for controlling sheath blight disease of rice
Trial Registration for Public Trust: Making the Case for Medical Devices
Recently, several pharmaceutical companies have been shown to have withheld negative clinical trial results from the public. These incidents have resulted in a concerted global effort to register all trials at inception, so that all subsequent results can be tracked regardless of whether they are positive or negative. These trial registration policies have been driven in large part by concern about the pharmaceutical sector. The medical device industry is much smaller, and different from the pharmaceutical industry in some fundamental ways. This paper examines the issues surrounding registration of device trials and argues that these differences with pharmaceutical should not exempt device trials from registration
Completeness and Changes in Registered Data and Reporting Bias of Randomized Controlled Trials in ICMJE Journals after Trial Registration Policy
We assessed the adequacy of randomized controlled trial (RCT) registration, changes to registration data and reporting completeness for articles in ICMJE journals during 2.5 years after registration requirement policy.For a set of 149 reports of 152 RCTs with ClinicalTrials.gov registration number, published from September 2005 to April 2008, we evaluated the completeness of 9 items from WHO 20-item Minimum Data Set relevant for assessing trial quality. We also assessed changes to the registration elements at the Archive site of ClinicalTrials.gov and compared published and registry data.RCTs were mostly registered before 13 September 2005 deadline (n = 101, 66.4%); 118 (77.6%) started recruitment before and 31 (20.4%) after registration. At the time of registration, 152 RCTs had a total of 224 missing registry fields, most commonly 'Key secondary outcomes' (44.1% RCTs) and 'Primary outcome' (38.8%). More RCTs with post-registration recruitment had missing Minimum Data Set items than RCTs with pre-registration recruitment: 57/118 (48.3%) vs. 24/31 (77.4%) (χ(2) (1) = 7.255, P = 0.007). Major changes in the data entries were found for 31 (25.2%) RCTs. The number of RCTs with differences between registered and published data ranged from 21 (13.8%) for Study type to 118 (77.6%) for Target sample size.ICMJE journals published RCTs with proper registration but the registration data were often not adequate, underwent substantial changes in the registry over time and differed in registered and published data. Editors need to establish quality control procedures in the journals so that they continue to contribute to the increased transparency of clinical trials
Vocal signals facilitate cooperative hunting in wild chimpanzees
Cooperation and communication likely co-evolved in humans. However, the evolutionary roots of this interdependence remain unclear. We address this issue by investigating the role of vocal signals in facilitating a group cooperative behavior in an ape species: hunting in wild chimpanzees. First, we show that bark vocalizations produced before hunt initiation are reliable signals of behavioral motivation, with barkers being most likely to participate in the hunt. Next, we find that barks are associated with greater hunter recruitment and more effective hunting, with shorter latencies to hunting initiation and prey capture. Our results indicate that the co-evolutionary relationship between vocal communication and group-level cooperation is not unique to humans in the ape lineage, and is likely to have been present in our last common ancestor with chimpanzees
Problem gambling: a suitable case for social work?
Problem gambling attracts little attention from health and social care agencies
in the UK. Prevalence surveys suggest that 0.6% of the population are
problem gamblers and it is suggested that for each of these individuals,
10–17 other people, including children and other family members, are
affected. Problem gambling is linked to many individual and social problems
including: depression, suicide, significant debt, bankruptcy, family conflict,
domestic violence, neglect and maltreatment of children and offending.
This makes the issue central to social work territory. Yet, the training of
social workers in the UK has consistently neglected issues of addictive
behaviour. Whilst some attention has been paid in recent years to substance
abuse issues, there has remained a silence in relation to gambling
problems. Social workers provide more help for problems relating to addictions
than other helping professions. There is good evidence that treatment,
and early intervention for gambling problems, including psycho-social and
public health approaches, can be very effective. This paper argues that
problem gambling should be moved onto the radar of the social work profession,
via inclusion on qualifying and post-qualifying training programmes
and via research and dissemination of good practice via institutions such as
the Social Care Institute for Excellence (SCIE).
Keywords: problem gambling; addictive behaviour; socia
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