962 resultados para Keenum, Mark E.


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Neotropical swarm-founding wasps build nests enclosed in a covering envelope, which makes it difficult to count individual births and deaths. Thus, knowledge of worker demography is very limited for swarm-founding species compared with that for independent-founding species. In this study, we explored the worker demography of the swarm-founding wasp Polybia paulista, the colony size of which usually exceeds several thousand adults. We considered each wasp colony as an open-population and estimated the survival probability, recruitment rate, and population size of workers using the developments of the Cormack-Jolly-Seber model. We found that capture probability varied considerably among the workers, probably due to age polyethism and/or task specialization. The daily survival rate of workers was high (around 0.97) throughout the season and was not related to the phase of colony development. On the other hand, the recruitment rate ranged from 0 to 0.37, suggesting that worker production was substantially less important than worker survival in determining worker population fluctuations. When we compared survival rates among worker groups of one colony, the mean daily survival rate was lower for founding workers than for progeny workers and tended to be higher in progeny workers that emerged in winter. These differences in survivorship patterns among worker cohorts would be related to worker foraging activity and/or level of parasitism.

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Models of population dynamics are commonly used to predict risks in ecology, particularly risks of population decline. There is often considerable uncertainty associated with these predictions. However, alternatives to predictions based on population models have not been assessed. We used simulation models of hypothetical species to generate the kinds of data that might typically be available to ecologists and then invited other researchers to predict risks of population declines using these data. The accuracy of the predictions was assessed by comparison with the forecasts of the original model. The researchers used either population models or subjective judgement to make their predictions. Predictions made using models were only slightly more accurate than subjective judgements of risk. However, predictions using models tended to be unbiased, while subjective judgements were biased towards over-estimation. Psychology literature suggests that the bias of subjective judgements is likely to vary somewhat unpredictably among people, depending on their stake in the outcome. This will make subjective predictions more uncertain and less transparent than those based on models. (C) 2004 Elsevier SAS. All rights reserved.

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Background: All cases of lung cancer diagnosed in Western Australia in 1996 in which surgery was the primary treatment, were reviewed. Reported herein are the characteristics of the patients, the treatment outcomes and a comparison of the management undertaken with that recommended by international guidelines. Methods: All patients with a new diagnosis of lung cancer in Western Australia in the calendar year of 1996 were identified using two different population-based registration systems: the Western Australian (WA) Cancer Registry and the WA Hospital Morbidity Data System. A structured questionnaire on the diagnosis and management was completed for each case. Date of death was determined through the WA Cancer Registry. Results: Six hundred and sixty-eight patients with lung cancer were identified; 132 (20%) were treated with surgery. Lobectomy was the most frequently performed procedure (71%), followed by pneumonectomy (19%). Major complications affected 23% of patients. Postoperative mortality was 6% (3% lobectomy, 12% pneumonectomy). At 5 years the absolute survival was as follows for stage I, II, IIIA, IIIB, respectively: 51%, 45%, 12%, 5%. Conclusions: Investigations and choice of surgery in WA in 1996 reflect current international guidelines. The survival of patients with resectable lung cancer remains unsatisfactory.

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In studies of mirror-self-recognition subjects are usually surreptitiously marked on their head, and then presented with a mirror. Scores of studies have established that by 18 to 24 months, children investigate their own head upon seeing the mark in the mirror. Scores of papers have debated what this means. Suggestions range from rich interpretations (e.g., the development of self-awareness) to lean accounts (e.g., the development of proprioceptivevisual matching), and include numerous more moderate proposals (e.g., the development of a concept of one's face). In Study 1, 18-24-monthold toddlers were given the standard test and a novel task in which they were marked on their legs rather than on their face. Toddlers performed equivalently on both tasks, suggesting that passing the test does not rely on information specific to facial features. In Study 2, toddlers were surreptitiously slipped into trouser legs that were prefixed to a highchair. Toddlers failed to retrieve the sticker now that their legs looked different from expectations. This finding, together with the findings from a third study which showed that self-recognition in live video feedback develops later than mirror selfrecognition, suggests that performance is not solely the result of proprioceptive-visual matching.

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Natural killer (NK) cells are innate effector lymphocytes necessary for defence against stressed, microbe-infected, or malignant cells. NK cells kill target cells by either of two major mechanisms that require direct contact between NK cells and target cells. In the first pathway, cytoplasmic granule toxins, predominantly a membrane-disrupting protein known as perforin, and a family of structurally related serine C, proteases (granzymes) with various substrate specificities, are secreted by exocytosis and together induce apoptosis of the target cell. The granule-exocytosis pathway potently activates cell-death mechanisms that operate through the activation of apoptotic cysteine proteases (caspases), but can also cause cell death in the absence of activated caspases. The second pathway involves the engagement of death receptors (e.g. Fas/CD95) on target cells by their cognate ligands (e.g. FasL on NK cells, resulting in classical caspase-dependent apoptosis. The comparative role of these pathways in the pathophysiology of many diseases is being dissected by analyses of gene-targeted mice that lack these molecules, and humans who have genetic mutations affecting these pathways. We are also now learning that the effector function of NK cells is controlled by interactions involving specific NK cell receptors and their cognate ligands, either on target cells, or other cells of the immune system. This review will discuss the functional importance of NK cell cytotoxicity and the receptor/ligand interactions that control these processes. (C) 2004 Elsevier Ltd. All rights reserved.

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We establish the existence of mild solutions for a class of impulsive second-order partial neutral functional differential equations with infinite delay in a Banach space. (C) 2009 Published by Elsevier Ltd

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In this paper we study the existence of mild solutions for a class of first order abstract partial neutral differential equations with state-dependent delay. (C) 2008 Elsevier Ltd. All rights reserved.

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We establish existence of mild solutions for a class of abstract second-order partial neutral functional differential equations with unbounded delay in a Banach space.

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This article examines book illustrations through the prism of Translation Studies. It mainly suggests that the pictures in illustrated books are (intersemiotic) translations of the text and that, as such, they can be analyzed making use of the same tools applied to verbal interlingual translation. The first section deals with the theoretical bases upon which illustrations can be regarded as translations, concentrating on theories of re-creation, as illustration is viewed essentially as the re-creation of the text in visual form. One of the claims in this section is that, because illustration is carried out in very similar ways as interlingual translation itself, the term ""intersemiotic"" relates more to the (obvious) difference of medium. For this reason the word is most often referred to in parentheses. The second section discusses three particular ways through which illustrations can translate the text, namely, by reproducing the textual elements literally in the picture, by emphasizing a specific narrative element, and by adapting the pictures to a certain ideology or artistic trend. The example illustrations are extracted from different. kinds of publication and media, ranging from Virgil`s Aeneid, Lewis Carroll`s Alice in Wonderland and Mark Twain`s Adventures of Huckleberry Finn to an online comic version of Shakespeare`s Hamlet.

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Because CD4(+) T cells play a key role in aiding cellular immune responses, we wanted to assess whether increasing numbers of gene-engineered antigen-restricted CD4(+) T cells could enhance an antitumor response mediated by similarly gene-engineered CD8(+) T cells. In this study, we have used retroviral transduction to generate erbB2-reactive mouse T-cell populations composed of various proportions of CD4(+) and CD8(+) cells and then determined the antitumor reactivity of these mixtures. Gene-modified CD4(+) and CD8(+) T cells were shown to specifically secrete Tc1 (T cytotoxic-1) or Tc2 cytokines, proliferate, and lyse erbB2(+) tumor targets following antigen ligation in vitro. In adoptive transfer experiments using severe combined immunodeficient (scid) mice, we demonstrated that injection of equivalent numbers of antigen-specific engineered CD8(+) and CD4(+) T cells led to significant improvement in survival of mice bearing established lung metastases compared with transfer of unfractionated (largely CD8(+)) engineered T cells. Transferred CD4(+) T cells had to be antigen-specific (not just activated) and secrete interferon gamma (IFN-gamma) to potentiate the antitumor effect. Importantly, antitumor responses in these mice correlated with localization and persistence of gene-engineered T cells at the tumor site. Strikingly, mice that survived primary tumor challenge could reject a subsequent re-challenge. Overall, this study has highlighted the therapeutic potential of using combined transfer of antigen-specific gene-modified CD8(+) and CD4(+) T cells to significantly enhance T-cell adoptive transfer strategies for cancer therapy.

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To discuss and share knowledge around advances in the care of patients with thrombotic disorders, the Third International Symposium of Thrombosis and Anticoagulation was held in So Paulo, Brazil, from October 14-16, 2010. This scientific program was developed by clinicians for clinicians, and was promoted by four major clinical research institutes: the Brazilian Clinical Research Institute, the Duke Clinical Research Institute of the Duke University School of Medicine, the Canadian VIGOUR Centre, and the Uppsala Clinical Research Center. Comprising 3 days of academic presentations and open discussion, the symposium had as its primary goal to educate, motivate, and inspire internists, cardiologists, hematologists, and other physicians by convening national and international visionaries, thought-leaders, and dedicated clinician-scientists. This paper summarizes the symposium proceedings.

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Few prospective data from the Asia Pacific region are available relating body mass index to the risk of diabetes. Our objective was to provide reliable age, sex and region specific estimates of the associations between body mass index and diabetes. Twenty-seven cohort studies from Asia, New Zealand and Australia, including 154,989 participants, contributed 1,244,793 person-years of follow-up. Outcome data included a combination of incidence of diabetes (based on blood glucose measurements) and fatal diabetes events. Hazard ratios were calculated from Cox models, stratified by sex and cohort, and adjusted for age at risk and smoking. During follow-up (mean = 8 years), 75 fatal diabetes events and 242 new cases of diabetes were documented. There were continuous positive associations between baseline body mass index and risk of diabetes with each 2 kg/m(2) lower body mass index associated with a 27% (23-30%) lower risk of diabetes. The associations were stronger in younger age groups, and regional comparisons demonstrated slightly stronger associations in Asian than in Australasian cohorts (P = 0.04). This overview provides evidence of a strong continuous association between body mass index and diabetes in the Asia Pacific region. The results indicate considerable potential for reduction in incidence of diabetes with population-wide lowering of body mass index in this region.

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Significant controversies surround the optimal treatment of primary hyperhidrosis of the hands, axillae, feet, and face. The world`s literature on hyperhidrosis from 1991 to 2009 was obtained through PubMed. There were 1,097 published articles, of which 102 were clinical trials. Twelve were randomized clinical trials and 90 were nonrandomized comparative studies. After review and discussion by task force members of The Society of Thoracic Surgeons` General Thoracic Workforce, expert consensus was reached from which specific treatment strategies are suggested. These studies suggest that primary hyperhidrosis of the extremities, axillae or face is best treated by endoscopic thoracic sympathectomy (ETS). Interruption of the sympathetic chain can be achieved either by electrocautery or clipping. An international nomenclature should be adopted that refers to the rib levels (R) instead of the vertebral level at which the nerve is interrupted, and how the chain is interrupted, along with systematic pre and postoperative assessments of sweating pattern, intensity and quality-of-life. The recent body of literature suggests that the highest success rates occur when interruption is performed at the top of R3 or the top of R4 for palmar-only hyperhidrosis. R4 may offer a lower incidence of compensatory hyperhidrosis but moister hands. For palmar and axillary, palmar, axillary and pedal and for axillary-only hyperhidrosis interruptions at R4 and R5 are recommended. The top of R3 is best for craniofacial hyperhidrosis. (Ann Thorac Surg 2011;91:1642-8) (C) 2011 by The Society of Thoracic Surgeons