937 resultados para target population of environments


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The transcription factor GATA-1 recognizes a consensus motif present in regulatory regions of numerous erythroid-expressed genes. Mouse embryonic stem cells lacking GATA-1 cannot form mature red blood cells in vivo. In vitro differentiation of GATA-1- embryonic stem cells gives rise to a population of committed erythroid precursors that exhibit developmental arrest and death. We show here that the demise of GATA-1- erythroid cells is accompanied by several features characteristics of apoptosis. This process occurs despite normal expression of all known GATA target genes examined, including the erythropoietin receptor, and independent of detectable accumulation of the tumor suppressor protein p53. Thus, in addition to its established role in regulating genes that define the erythroid phenotype, GATA-1 also supports the viability of red cell precursors by suppressing apoptosis. These results illustrate the multifunctional nature of GATA-1 and suggest a mechanism by which other hematopoietic transcription factors may ensure the development of specific lineages.

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Prolonged incubation of NIH 3T3 cells under the growth constraint of confluence results in the death of some cells in a manner suggestive of apoptosis. Successive rounds of prolonged incubation at confluence of the surviving cells produce increasing neoplastic transformation in the form of increments in saturation density and transformed focus formation. Cells from the postconfluent cultures are given a recovery period of various lengths to remove the direct inhibitory effect of confluence before their growth properties are studied. It is found that with each round of confluence the exponential growth rate of the cells at low densities gets lower and the size of isolated colonies of the same cells shows a similar progressive reduction. The decreased growth rate of cells from the third round of confluence persists for > 60 generations of growth at low density. The proportion of colonies containing giant cells is much higher after a 2-day recovery from confluence than after a 7-day recovery. Retardation of growth at low density and increased saturation density appear to be two sides of the same coin: both occur in the entire population of cells and precede the formation of transformed foci. We propose that the slowdown in growth and the formation of giant cells result from heritable damage to the cells, which in turn drives their transformation. Similar results have been reported for the survivors of x-irradiation and of treatment with chemical carcinogens and are associated with the aging process in animals. We suggest that these changes result from free radical damage to membrane lipids with particular damage to lysosomes. Proteases and nucleases would then be released to progressively modify the growth behavior and genetic stability of the cells toward autonomous proliferation.

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We present the results of a breeding census of Dupont’s Lark carried out in the Autonomous Community of Valencia in 2011 using the mapping method and an analysis of the recent trend for this population. The population was estimated at 44-47 males, located in five habitat patches of the Rincón de Ademuz, in zones where the species had been detected previously. Density in these patches fits within values expected according to the relation between patch size and density found in the populations of the nearby provinces. Comparison to previous studies reveals that population of Valencia has suffered an annual decline rate of around 10% on average, thus the implementation of a conservation plan is required to ensure the survival of the species in the study area.

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The aim of this paper was to evaluate the relationship between selected indicators of obesity and the highest completed level of education in the adult female population of the Czech republic. As basic indicators of obesity, these following parameters were selected and measured via the bioimpedance method on the device InBody 720: BMI, WHR (waist-to-hip ratio), % body fat, % skeletal muscle mass, fitness score. The educational attainment of the tested women was inquired by a questionnaire. Based on the responses, we subsequently divided our sample into four categories according to the level of education: primary education, secondary education-apprenticeship, secondary education-graduate diploma, and university. The research was realized within the project CZ.1.07/2.3.00/20.0044. The measurements on the device InBody 720 and the accompanying survey were conducted between 2011-2013 in different regions of the Czech Republic. The sample consisted of 754 women divided into 3 age groups (18-39, 40-59, 60+ years). Based on the results (p<0.05), we can say that average values of the indicators obesity (BMI: 22.76, 24.88, 26.49 kg/m2, WHR: 0.85, 0.88, 0.90 and % body fat: 25.76, 30.23, 34.62%) increase with the increasing age of examined women. The average values of the fitness score (75.53, 73.86, 70.04 points) and % skeletal muscle mass (40.78, 38.15, 33.95%) decrease with increasing age. With regard to the educational attainment, women with secondary education-apprenticeship achieved the worst results. In contrast, the values in university educated women were the best in most indicators of obesity.

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Aims. In this study we conduct a pilot program aimed at the red supergiant population of the Magellanic Clouds. We intend to extend the current known sample to the unexplored low end of the brightness distribution of these stars, building a more representative dataset with which to extrapolate their behaviour to other Galactic and extra-galactic environments. Methods. We select candidates using only near infrared photometry, and with medium resolution multi-object spectroscopy, we perform spectral classification and derive their line-of-sight velocities, confirming the nature of the candidates and their membership in the clouds. Results. Around two hundred new red supergiants have been detected, hinting at a yet to be observed large population. Using near- and mid-infrared photometry we study the brightness distribution of these stars, the onset of mass-loss, and the effect of dust in their atmospheres. Based on this sample, new a priori classification criteria are investigated, combining mid- and near-infrared photometry to improve the observational efficiency of similar programs to this.

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End-stage liver disease associated with hepatitis C virus (HCV) infection is now the leading indication for liver transplantation in adults. However, reinfection of the graft is universal. We aimed to determine predictors of outcome of HCV-Iiver transplant recipients in the Australian and New Zealand communities. The following variables were analysed: demographic factors, coexistent pathology at the time of transplantation, HCV genotype, and donor age. Outcomes measures were: 1. mortality; 2. development of HCV-related complications, which were stage 3 or 4 fibrosis, or mortality from HCV-related graft failure, or both. Between January 1989 and December 30, 1999, 182 patients were transplanted for HCV-associated cirrhosis. The median follow-up period was 4 years (range, 0 to 13 years). Genotype data were available on 157 patients. The distribution of genotypes among the 157 patients was as follows: 36 (23%) genotype la, 30 (19%) genotype 1b, 4 (9%) genotype 1, 17 (11%) genotype 2, 41 (26%) genotype 3a, and 16 (10%) genotype 4. Eight (5%) patients were HCV-polymerase chain reaction (PCR)-negative (but HCV-antibody positive). Donor age and genotype 4 were associated with an increased risk of retransplantation or death (P < .001 and.05, respectively). Meanwhile, donor age, genotype 4, and pretransplant excess alcohol were risk factors for the development of HCV-related complications (P = .004, .008, and .02, respectively). In contrast, patients with genotype 3a were less likely to develop HCV-related complications (P = .05). In a population of HCV liver transplant recipients with a heterogeneous genotype distribution, donor age, and genotype 4, were predictors of a worse outcome, whereas genotype 3 was associated with a more favorable outcome.

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Primary objective : To establish a process whereby assessment of functional communication reflects the authentic communication of the target population. The major functional communication assessments available from the USA may not be as relevant to those who reside elsewhere, nor assessments developed primarily for persons who have had a stroke as relevant for traumatic brain injury rehabilitation. Research design : The investigation used the Nominal Group Technique to elicit free opinion and support individuals who have compromised communication ability. A survey mailed out sampled a larger number of stakeholders to test out differences among groups. Methods and procedures : Five stakeholder groups generated items and the survey determined relative 'importance'. The stakeholder groups in both studies comprised individuals with traumatic brain injury and their families, health professionals, third-party payers, employers, and Maori, the indigenous population of New Zealand. Main outcomes and results : There was no statistically significant difference found between groups for 19 of the 31 items. Only half of the items explicitly appear on a well-known USA functional communication assessment. Conclusions : The present study has implications for whether functional communication assessments are valid across cultures and the type of impairment.

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Molecular tools for the species-specific detection of Gluconacetobacter sacchari, Gluconacetobacter diazotrophicus, and Gluconacetobacter liquefaciens from the pink sugarcane mealybug (PSMB) Saccharicoccus sacchari Cockerell (Homiptera: Pseudococcidae) were developed and used in polymerase chain reactions (PCR) and in fluorescence in situ hybridizations (FISH) to better understand the microbial diversity and the numerical significance of the acetic acid bacteria in the PSMB microenvironment. The presence of these species in the PSMB occurred over a wide range of sites, but not in all sites in sugarcane-growing areas of Queensland, Australia, and was variable over time. Molecular probes for use in FISH were also designed for the three acetic acid bacterial species, and shown to be specific only for the target species. Use of these probes in FISH of squashed whole mealybugs indicated that these acetic acid bacteria species represent only a small proportion of the microbial population of the PSMB. Despite the detection of Glac. sacchari, Glac. diazotrophicus, and Glac. liquefaciens by PCR from different mealybugs isolated at various times and from various sugarcane-growing areas in Queensland, Australia, these bacteria do not appear to be significant commensals in the PSMB environment.

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Background: evaluation of the 'Keep Well At Home' (KWAH) Project in West London indicated that a programme of screening persons aged 75 and over had not reduced rates of emergency attendances and admissions to hospital. However, coverage of the target population was incomplete. The present analysis addresses 'efficacy'-whether individuals who completed the screening protocol as intended did subsequently use Accident & Emergency (A&E) services less often. Methods: the target population was divided into five groups, depending on whether an individual had completed none, one or both phases of screening, and whether deviations from the protocol related to incomplete coverage or refusal to participate further. We ascertained use of emergency services before screening and for up to 3 years afterwards by linkage of records from KWAH to those of local A&E Departments. Patterns of emergency care were examined as crude races and, via proportional hazards models, after adjustment for available confounders. Results: there was an increase of 51% (95% CI 22-86%) in the crude rate of emergency admissions in the year after first-phase screening compared with the 12 months before assessment. This was most obvious in individuals deemed at high risk who also underwent the second-phase assessment (adjusted hazard ratio relative to individuals not 'at risk'= 2.33; 95% CI 1.59-3.42). Conclusions: the available data do not allow us to distinguish between several possible explanations for the paradoxical increase in use of emergency services. However, what seem to be sensible policies do not necessarily have their intended effects when implemented in practice.

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Penaeid prawns were sampled with a small seine net to test whether catches of postlarvae and juveniles in seagrass were affected by the distance of the seagrass (mainly Zostera capricorni) from mangroves and the density of the seagrass in a subtropical marine embayment. Sampling was replicated on the western and eastern sides of Moreton Bay, Queensland, Australia. Information on catches was combined with broad-scale spatial information on the distribution of habitats to estimate the contribution of four different categories of habitat (proximal dense seagrass, distal dense seagrass, proximal sparse seagrass, distal sparse seagrass) to the overall population of small prawns in these regions of Moreton Bay. The abundance of Penaeus plebejus and Metapenaeus bennettae was significantly and consistently greater in dense seagrass proximal to mangroves than in other types of habitat. Additionally, sparse seagrass close to mangroves supported more of these species than dense seagrass farther away, indicating that the role of spatial arrangement of habitats was more important than the effects of structural complexity alone. In contrast, the abundance of P. esculentus tended to be greatest in sparse seagrass distal from mangroves compared with the other habitats. The scaling up of the results from different seagrass types suggests that proximal seagrass beds on both sides of Moreton Bay provide by far the greatest contribution of juvenile M. bennettae and P. plebejus to the overall populations in the Bay.

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Study objective: UK government policy mandates the introduction of 'intermediate care services' to reduce emergency admissions to hospital from the population aged 75 years or more. We evaluated one of these initiatives-the Keep Well At Home (KWAH) Project-in a West London Primary Care Trust. Design: KWAH involves a two-phase screening process, including a home visit by a community nurse. We employed cohort methods to determine whether KWAH resulted in fewer emergency attendances and admissions to hospital in the target population, from October 1999 to December 2002. Results: estimated levels of coverage in the two phases of screening were 61 and 32%, respectively. The project had not maintained records of which additional health and social care services had been delivered following screening. The rates of emergency admissions to hospital in the 9 months before screening were similar in practices that did and did not join the project (rate ratio (RR) = 1.05; 95% CI 0.95-1.17), suggesting absence of volunteer bias. Over the first 37 months of the project, there was no significant impact on either attendances at Accident & Emergency departments (RR = 1.02; 95% CI 0.97-1.06) or emergency admissions of elderly patients (RR = 0.98; 95% CI 0.93-1.05). Conclusion: the KWAH Project has been ineffective in reducing emergency admissions among the elderly. Significant questions arise in relation to selection of the screening instruments, practicality of achieving higher coverage of the eligible population, and creation of a new postcode lottery.

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Most studies on kidney development have considered the interaction of the metanephric mesenchyme and the ureteric bud to be the major inductive event that maintains tubular differentiation and branching morphogenesis. The mesenchyme produces Gdnf, which stimulates branching, and the ureteric bud stimulates continued growth of the mesenchyme and differentiation of nephrons from the induced mesenchyme. Null mutation of the Wt1 gene eliminates outgrowth of the ureteric bud, but Gdnf has been identified as a target of Pax2, but not of Wt1. Using a novel system for microinjecting and electroporating plasmid expression constructs into murine organ cultures, it has been demonstrated that Vegfa expression in the mesenchyme is regulated by Wt1. Previous studies had identified a population of Flk1-expressing cells in the periphery of the induced mesenchyme, and adjacent to the stalk of the ureteric bud, and that Vegfa was able to stimulate growth of kidneys in organ culture. Here it is demonstrated that signaling through Flk1 is required to maintain expression of Pax2 in the mesenchyme of the early kidney, and for Pax2 to stimulate expression of Gdnf. However, once Gdnf stimulates branching of the ureteric bud, the Flk1-dependent angioblast signal is no longer required to maintain branching morphogenesis and induction of nephrons. Thus, this work demonstrates the presence of a second set of inductive events, involving the mesenchymal and angioblast populations, whereby Wt1-stimulated expression of Vegfa elicits an as-yet-unidentified signal from the angioblasts, which is required to stimulate the expression of Pax2 and Gdnf, which in turn elicits an inductive signal from the ureteric bud.

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It has long been recognized that demographic structure within a population can significantly affect the likely outcomes of harvest. Many studies have focussed on equilibrium dynamics and maximization of the value of the harvest taken. However, in some cases the management objective is to maintain the population at a abundance that is significantly below the carrying capacity. Achieving such an objective by harvest can be complicated by the presence of significant structure (age or stage) in the target population. in such cases, optimal harvest strategies must account for differences among age- or stage-classes of individuals in their relative contribution to the demography of the population. In addition, structured populations are also characterized by transient non-linear dynamics following perturbation, such that even under an equilibrium harvest, the population may exhibit significant momentum, increasing or decreasing before cessation of growth. Using simple linear time-invariant models, we show that if harvest levels are set dynamically (e.g., annually) then transient effects can be as or more important than equilibrium outcomes. We show that appropriate harvest rates can be complicated by uncertainty about the demographic structure of the population, or limited control over the structure of the harvest taken. (c) 2006 Elsevier B.V. All rights reserved.

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This Article Right arrow Full Text Right arrow Full Text (PDF) Right arrow Supplemental material Right arrow Alert me when this article is cited Right arrow Alert me if a correction is posted Services Right arrow Similar articles in this journal Right arrow Similar articles in PubMed Right arrow Alert me to new issues of the journal Right arrow Download to citation manager Right arrow Reprints and Permissions Right arrow Copyright Information Right arrow Books from ASM Press Right arrow MicrobeWorld Citing Articles Right arrow Citing Articles via HighWire Right arrow Citing Articles via Google Scholar Google Scholar Right arrow Articles by Lee, N. Right arrow Articles by McCarthy, J. Right arrow Search for Related Content PubMed Right arrow PubMed Citation Right arrow Articles by Lee, N. Right arrow Articles by McCarthy, J. Right arrow Pubmed/NCBI databases * Substance via MeSH Previous Article | Next Article Journal of Clinical Microbiology, August 2006, p. 2773-2778, Vol. 44, No. 8 0095-1137/06/$08.00+0 doi:10.1128/JCM.02557-05 Copyright © 2006, American Society for Microbiology. All Rights Reserved. Effect of Sequence Variation in Plasmodium falciparum Histidine- Rich Protein 2 on Binding of Specific Monoclonal Antibodies: Implications for Rapid Diagnostic Tests for Malaria{dagger} Nelson Lee,1,2 Joanne Baker,2 Kathy T. Andrews,1 Michelle L. Gatton,1,3 David Bell,4 Qin Cheng,2,3 and James McCarthy1* Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research and School of Population Health, University of Queensland, Queensland, Australia,1 Department of Drug Resistance and Diagnostics, Australian Army Malaria Institute, Brisbane, Australia,2 Malaria Drug Resistance and Chemotherapy, Queensland Institute of Medical Research, Queensland, Australia,3 World Health Organization, Regional Office for the Western Pacific, Manila, Philippines4 Received 8 December 2005/ Returned for modification 23 February 2006/ Accepted 26 May 2006 The ability to accurately diagnose malaria infections, particularly in settings where laboratory facilities are not well developed, is of key importance in the control of this disease. Rapid diagnostic tests (RDTs) offer great potential to address this need. Reports of significant variation in the field performance of RDTs based on the detection of Plasmodium falciparum histidine-rich protein 2 (HRP2) (PfHRP2) and of significant sequence polymorphism in PfHRP2 led us to evaluate the binding of four HRP2-specific monoclonal antibodies (MABs) to parasite proteins from geographically distinct P. falciparum isolates, define the epitopes recognized by these MABs, and relate the copy number of the epitopes to MAB reactivity. We observed a significant difference in the reactivity of the same MAB to different isolates and between different MABs tested with single isolates. When the target epitopes of three of the MABs were determined and mapped onto the peptide sequences of the field isolates, significant variability in the frequency of these epitopes was observed. These findings support the role of sequence variation as an explanation for variations in the performance of HRP2-based RDTs and point toward possible approaches to improve their diagnostic sensitivities