403 research outputs found
Explaining Long-Distance Dispersal: Effects of Dispersal Distance on Survival and Growth in a Stream Salamander
Long-distance dispersal (LDD) may contribute disproportionately to range expansions, the creation of new evolutionary lineages, and species persistence in human-dominated landscapes. However, because data on the individual consequences of dispersal distance are extremely limited, we have little insight on how LDD is maintained in natural populations. I used six years of spatially explicit capture–mark–recapture (CMR) data to test the prediction that individual performance increases with dispersal distance in the stream salamander Gyrinophilus porphyriticus. Dispersal distance was total distance moved along the 1-km study stream, ranging from 0 to 565 m. To quantify individual performance, I used CMR estimates of survival and individual growth rates based on change in body length. Survival and growth rates increased significantly with dispersal distance. These relationships were not confounded by pre-dispersal body condition or by ecological gradients along the stream. Individual benefits of LDD were likely caused by an increase in the upper limit of settlement site quality with dispersal distance. My results do not support the view that the fitness consequences of LDD are unpredictable and instead suggest that consistent evolutionary mechanisms may explain the prevalence of LDD in nature. They also highlight the value of direct CMR data for understanding the individual consequences of variation in dispersal distance and how that variation is maintained in natural populations
Relating colour, chemical and physical characteristics of artificially light-aged New Zealand plant fibres
Light ageing of naturally-dyed plant fibres can cause colour change, alteration of molecular bonds within the fibre structure and loss of mechanical integrity. Lighting guidelines seek to protect artefacts by limiting light exposure, for example by estimating the lux hours likely to cause colour change of “one just noticeable fade” (1JNF). However the extent of associated molecular or mechanical damage is rarely simultaneously assessed.
This paper reports a pilot study investigating the effects of accelerated light ageing on muka (fibre extracted from the leaves of Phormium tenax), the most common fibre used in Māori textiles. Non-dyed and dyed muka were artificially light-aged and micro-faded to ascertain exposure resulting in 1JNF. Raman microscopy and tensile testing of individual fibres from the same samples were used to explore correlations among fading, molecular change and mechanical properties.Peer Reviewe
Testing the cognitive-behavioural maintenance models across DSM-5 bulimic-type eating disorder diagnostic groups: A multi-centre study
The original cognitive-behavioural (CB) model of bulimia nervosa, which provided the basis for the widely used CB therapy, proposed that specific dysfunctional cognitions and behaviours maintain the disorder. However, amongst treatment completers, only 40–50 % have a full and lasting response. The enhanced CB model (CB-E), upon which the enhanced version of the CB treatment was based, extended the original approach by including four additional maintenance factors. This study evaluated and compared both CB models in a large clinical treatment seeking sample (N = 679), applying both DSM-IV and DSM-5 criteria for bulimic-type eating disorders. Application of the DSM-5 criteria reduced the number of cases of DSM-IV bulimic-type eating disorders not otherwise specified to 29.6 %. Structural equation modelling analysis indicated that (a) although both models provided a good fit to the data, the CB-E model accounted for a greater proportion of variance in eating-disordered behaviours than the original one, (b) interpersonal problems, clinical perfectionism and low self-esteem were indirectly associated with dietary restraint through over-evaluation of shape and weight, (c) interpersonal problems and mood intolerance were directly linked to binge eating, whereas restraint only indirectly affected binge eating through mood intolerance, suggesting that factors other than restraint may play a more critical role in the maintenance of binge eating. In terms of strength of the associations, differences across DSM-5 bulimic-type eating disorder diagnostic groups were not observed. The results are discussed with reference to theory and research, including neurobiological findings and recent hypotheses
Host pathogen interactions in relation to management of light leaf spot disease (caused by Pyrenopeziza brassicae) on Brassica species
Light leaf spot, caused by Pyrenopeziza brassicae, is currently the most damaging disease problem in oilseed rape in the UK. According to recent survey data, the severity of epidemics has increased progressively across the UK, with current yield losses of up to £160M per annum in England and more severe epidemics in Scotland. Light leaf spot is a polycyclic disease with primary inoculum consisting of air-borne ascospores produced on diseased debris from the previous cropping season. Splash-dispersed conidia produced on diseased leaves are the main component of the secondary inoculum. P. brassicae is also able to infect and cause considerable yield losses on vegetable brassicas, especially Brussels sprouts. There may be spread of light leaf spot among different brassica species. Since they have a wide host range, Pyrenopeziza brassicae populations are likely to have considerable genetic diversity and there is evidence suggesting population variations between different regions, which need further study. Available disease-management tools are not sufficient to provide adequate control of the disease. There is a need to identify new sources of resistance, which can be integrated with fungicide applications to achieve sustainable management of light leaf spot. Several major resistance genes and quantitative trait loci have been identified in previous studies, but rapid improvements in the understanding of molecular mechanisms underpinning B. napus – P. brassicae interactions can be expected through exploitation of novel genetic and genomic information for brassicas and extracellular fungal pathogens.Peer reviewe
Niche-breadth of freshwater macrophytes occurring in tropical southern African rivers predicts species global latitudinal range
The study tested the hypothesis that measurement, using multivariate Principal Components Analy-sis (PCA), of the niche-breadth of river macrophyte species in southern tropical Africa, may predicttheir larger-scale biogeographical range. Two measures of niche-breadth were calculated for 44 riverinemacrophyte species, from 20 families commonly occurring in Zambia, using an approach based on PCAordination with 16 bio-physico-chemical input variables. These included altitude, stream order, streamflow, pH, conductivity and soluble reactive phosphate concentration (SRP). In the absence of additionalchemical water quality data for Zambian rivers, invertebrate-based measures of general water qualitywere also used. These were benthic macroinvertebrate Average Score per Taxon (ASPT), and individualabundance of nine macroinvertebrate families with differing water quality tolerance, indicated by theirSensitivity Weightings within the Zambian Invertebrate Scoring System (ZISS). Macrophyte large-scalelatitudinal range was derived from world geopositional records held by online databases, and additionalrecords held by the authors. The two niche-breadth metrics divided the species into narrow-niche andintermediate/broad-niche categories, showing significant variation (from one or both of correlation andANOVA test outcomes) in altitude, stream flow, conductivity, SRP, pH and ASPT, but not stream order.Macrophyte alpha-diversity (as a measure of number of individual niches co-existing per habitat) showedno significant relationship with individual species niche-breadth. Narrow-niche species included a higherproportion of Afrotropical endemics than did species with broader niche size. There were significant pre-dictive relationships between macrophyte niche-breadth and latitudinal range of the target species atglobal and Afrotropical scales, but not for the Neotropics.Fil: Kennedy, Michael. University Of Aberdeen; Reino UnidoFil: Lang, Pauline. University of Glasgow; Reino UnidoFil: Tapia Grimaldo, Julissa. University of Glasgow; Reino UnidoFil: Varandas Martins, Sara. University of Glasgow; Reino UnidoFil: Bruce, Alannah. University of Glasgow; Reino UnidoFil: Moore, Isabel. University of Glasgow; Reino UnidoFil: Taubert, Rebeca. University of Glasgow; Reino UnidoFil: Macleod-Nolan, Chantal. University of Glasgow; Reino UnidoFil: McWaters, Stephanie. University of Glasgow; Reino UnidoFil: Briggs, John. University of Glasgow; Reino UnidoFil: Lowe, Steve. University of Glasgow; Reino UnidoFil: Saili, Kochelani. University Of Zambia;Fil: SICHINGABULA, Henry. University Of Zambia;Fil: Dallas, Helen. Nelson Mandela Metropolitan University, Sudafrica; SudáfricaFil: Morrison, Sean. University of Glasgow; Reino UnidoFil: Franceschini, Maria Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Willems, Frank. The Kasanka Trust; ZambiaFil: Bottino, Flavia. Universidad Federal de San Carlos; BrasilFil: MURPHY Kevin. University of Glasgow; Reino Unid
Object Detection Through Exploration With A Foveated Visual Field
We present a foveated object detector (FOD) as a biologically-inspired
alternative to the sliding window (SW) approach which is the dominant method of
search in computer vision object detection. Similar to the human visual system,
the FOD has higher resolution at the fovea and lower resolution at the visual
periphery. Consequently, more computational resources are allocated at the
fovea and relatively fewer at the periphery. The FOD processes the entire
scene, uses retino-specific object detection classifiers to guide eye
movements, aligns its fovea with regions of interest in the input image and
integrates observations across multiple fixations. Our approach combines modern
object detectors from computer vision with a recent model of peripheral pooling
regions found at the V1 layer of the human visual system. We assessed various
eye movement strategies on the PASCAL VOC 2007 dataset and show that the FOD
performs on par with the SW detector while bringing significant computational
cost savings.Comment: An extended version of this manuscript was published in PLOS
Computational Biology (October 2017) at
https://doi.org/10.1371/journal.pcbi.100574
Evaluation of menogaril in renal cell carcinoma
The Southwest Oncology Group (SWOG) studied the response rate and toxicity of menogaril (200 mg/m 2 i.v. q 28 days) in patients with advanced metastatic renal cell carcinoma. During the early stage of the trial two partial responses were seen in the first 20 treated patients, and an additional 36 evaluable patients were studied. Three of 56 (5%) evaluable patients achieved partial responses. Significant white cell toxicity was observed. Mild or moderate degrees of thrombocytopenia, gastrointestinal side effects, alopecia and phlebitis occurred. No cardiac toxicity was noted. The low response rate suggests that menogaril in this dose schedule has no role in the treatment of patients with advanced metastatic renal cancer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45344/1/10637_2004_Article_BF00171987.pd
- …