2,468 research outputs found
Predation of artificial nests in UK farmland by magpies (Pica pica): interacting environmental, temporal, and social factors influence a nest's risk
This is the final version. Available from the publisher via the DOI in this record.The recent decline in farmland songbirds in the UK has coincided with increases in the populations of many nest predators. However, studies which have removed nest predators and monitored the response of prey populations have found mixed results. One explanation for this ambiguity is that, within species, predators differ in how likely they are to predate nests and only the removal of particularly predatory individuals will improve the breeding success of prey populations. Predators could differ in the extent to which they take nests due to variation in the local environment and/or variation within the predator population, e.g. differences in breeding status. Additional to these broad factors, certain individuals may specialise on particular prey. We placed 460 artificial nests in a systematically balanced design in UK farmland to analyse these sources of variation in predation. Magpies (Pica pica) were the most common predators of our artificial nests and the vulnerability of our nests to magpie predation varied according to magpie breeding status (predation was higher inside breeding magpies’ territories), but this effect varied temporally. More nests were predated inside of magpie territories late in the season, when magpies had dependent fledglings. More specifically, some nest locations were especially vulnerable independent of both magpie breeding status and time in breeding season. These nests may have been disproportionately predated by specific, particularly predatory, territorial magpies. Habitat management and/or predator removal may benefit songbird populations if targeted towards reducing the effect of particular individuals identified as more likely to predate songbird nests.SongBird Surviva
Duramycin-porphyrin conjugates for targeting of tumour cells using photodynamic therapy
Duramycin, through binding with phosphatidylethanolamine (PE), has been shown to be a selective molecular probe for the targeting and imaging of cancer cells. Photodynamic therapy aims to bring about specific cytotoxic damage to tumours through delivery of a photosensitising agent and light irradiation. Conjugation to biological molecules that specifically target cancer has been shown to increase photosensitiser (PS) selectivity and decrease damage to surrounding normal tissue. The aim of this study was to target tumour cells with a PE-specific PS therefore duramycin was conjugated to a porphyrin based PS which was achieved via direct reaction with the ε-amino group on the lysine residue near duramycin's N-terminal. The compound was subsequently purified using RP-HPLC and confirmed using mass spectrometry. Binding of the conjugate to ovarian and pancreatic cancer cell lines was assessed by flow cytometry. Light irradiation with a light fluence of 7.5 J/cm2 was delivered to conjugate treated cancer cells and cell proliferation analysed by MTT assay. The conjugate detected PE on all 4 cancer cell lines in a concentration dependent manner and conjugate plus irradiation effectively reduced cell proliferation at concentrations ≥0.5 μM, dependent on cancer cell line. Reduction in cell proliferation by the irradiated conjugate was enhanced over unconjugated duramycin in A2780, AsPC-1 and SK-OV-3 (p b 0.05). In this study we have shown that a duramycin-porphyrin conjugate retained good binding affinity for its target and, following irradiation, reduced cell proliferation of pancreatic and ovarian cancer cell lines
What happens after James Lind Alliance Priority-Setting Partnerships? A qualitative study of contexts, processes and impacts
Sabotage in Contests: A Survey
A contest is a situation in which individuals expend irretrievable resources to win valuable prize(s). ‘Sabotage’ is a deliberate and costly act of damaging a rival’s' likelihood of winning the contest. Sabotage can be observed in, e.g., sports, war, promotion tournaments, political or marketing campaigns. In this article, we provide a model and various perspectives on such sabotage activities and review the economics literature analyzing the act of sabotage in contests. We discuss the theories and evidence highlighting the means of sabotage, why sabotage occurs, and the effects of sabotage on individual players and on overall welfare, along with possible mechanisms to reduce sabotage. We note that most sabotage activities are aimed at the ablest player, the possibility of sabotage reduces productive effort exerted by the players, and sabotage may lessen the effectiveness of public policies, such as affirmative action, or information revelation in contests. We discuss various policies that a designer may employ to counteract sabotage activities. We conclude by pointing out some areas of future research
The prognostic value of systemic inflammation in patients undergoing surgery for colon cancer: comparison of composite ratios and cumulative scores
Introduction:
The systemic inflammatory response has been proven to have a prognostic value. There are two methods of assessing the systemic inflammatory response composite ratios (R) and cumulative scores (S). The aim of this study was to compare the prognostic value of ratios and scores in patients undergoing surgery for colon cancer.
Methods:
Patients were identified prospectively in a single surgical unit. Preoperative neutrophil (N), lymphocyte (L), monocyte (M) and platelet (P) counts, CRP (C) and albumin (A) levels were recorded. The relationship between composite ratios neutrophil–lymphocyte ratio (NLR), platelet–lymphocyte ratio (PLR), lymphocyte–monocyte ratio (LMR), C-reactive protein albumin ratio (CAR) and the cumulative scores neutrophil– lymphocyte score (NLS), platelet–lymphocyte score (PLS), lymphocyte–monocyte score (LMS), neutrophil– platelet score (NPS), modified Glasgow prognostic score (mGPS) and clinicopathological characteristics, cancer-specific survival (CSS) and overall survival (OS), were examined.
Results:
A total of 801 patients were examined. When adjusted for tumour node metastasis (TNM) stage, NLR >5 (p < 0.001), NLS (p < 0.01), PLS (p < 0.001), LMR <2.4 (p < 0.001), LMS (p < 0.001), NPS (p < 0.001), CAR >0.22 (p < 0.001) and mGPS (p < 0.001) were significantly associated with CSS. In patients undergoing elective surgery (n = 689), the majority of the composite ratios/scores correlated with age (p < 0.01), BMI (p < 0.01), T stage (p < 0.01), venous invasion (p < 0.01) and peritoneal involvement (p < 0.01). When NPS (myeloid) and mGPS (liver) were directly compared, their relationship with CSS and OS was similar.
Conclusions:
Both composite ratios and cumulative scores had prognostic value, independent of TNM stage, in patients with colon cancer. However, cumulative scores, based on normal reference ranges, are simpler and more consistent for clinical use
A framework for mapping, visualisation and automatic model creation of signal-transduction networks
An intuitive formalism for reconstructing cellular networks from empirical data is presented, and used to build a comprehensive yeast MAP kinase network. The accompanying rxncon software tool can convert networks to a range of standard graphical formats and mathematical models
Spatial cognitive ability is associated with transitory movement speed but not straightness during the early stages of exploration
Memories about the spatial environment, such as the locations of foraging patches, are expected to affect how individuals move around the landscape. However, individuals differ in the ability to remember spatial locations (spatial cognitive ability) and evidence is growing that these inter-individual differences influence a range of fitness proxies. Yet empirical evaluations directly linking inter-individual variation in spatial cognitive ability and the development and structure of movement paths are lacking. We assessed the performance of young pheasants ( Phasianus colchicus ) on a spatial cognition task before releasing them into a novel, rural landscape and tracking their movements. We quantified changes in the straightness and speed of their transitory paths over one month. Birds with better performances on the task initially made slower transitory paths than poor performers but by the end of the month, there was no difference in speed. In general, birds increased the straightness of their path over time, indicating improved efficiency independent of speed, but this was not related to performance on the cognitive task. We suggest that initial slow movements may facilitate more detailed information gathering by better performers and indicates a potential link between an individual's spatial cognitive ability and their movement behaviour. </jats:p
PROTDES: CHARMM toolbox for computational protein design
We present an open-source software able to automatically mutate any residue positions and find the best aminoacids in an arbitrary protein structure without requiring pairwise approximations. Our software, PROTDES, is based on CHARMM and it searches automatically for mutations optimizing a protein folding free energy. PROTDES allows the integration of molecular dynamics within the protein design. We have implemented an heuristic optimization algorithm that iteratively searches the best aminoacids and their conformations for an arbitrary set of positions within a structure. Our software allows CHARMM users to perform protein design calculations and to create their own procedures for protein design using their own energy functions. We show this by implementing three different energy functions based on different solvent treatments: surface area accessibility, generalized Born using molecular volume and an effective energy function. PROTDES, a tutorial, parameter sets, configuration tools and examples are freely available at http://soft.synth-bio.org/protdes.html
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