289 resultados para Wayfaring life.
Resumo:
Parasitism is often a source of variation in host's fitness components. Understanding and estimating its relative importance for fitness components of hosts is fundamental from physiological, ecological and evolutionary perspectives. Host-parasite studies have often reported parasite-induced reduction of host fecundity, whereas the effect of parasitism on host survival has been largely neglected. Here, we experimentally investigated the effect of infestation by rat fleas (Nosopsyllus fasciatus) on the life span of wild-derived male common voles (Microtus arvalis) bred in captivity. We found that the mean life span of parasitized voles was reduced by 36% compared to control voles. Parasitized voles had a smaller body size, but a relatively larger heart and spleen than control voles. These results indicate an effect of flea infestation on host life span and our findings strongly suggest that ectoparasites should be taken into account in the studies of host population dynamics.
Resumo:
Health-related quality of life (HRQoL) was evaluated in a sample of alcohol-dependent patients with the 36-item Medical Outcome Study Short-Form Health Survey (MOS-SF-36). The instrument was administered to 147 patients (77% males), aged 26-78, with a DSM-III-R diagnosis of alcohol dependence. The Hamilton Depression Scale (HDS), the Severity of Alcohol Dependence Questionnaire (SADQ), and the Addiction Severity Index (ASI) were also administered to the first 100 patients included in the study. The reliability and validity of the MOS-SF-36 were evaluated. Test-retest intraclass coefficients for a 10-day interval were in the range .65 to .79, whereas the Cronbach alpha coefficient indicated good internal consistency (range .70 to .89). Compared to scores observed in the general population, MOS-SF-36 scores for alcohol-dependent patients were relatively low (indicating worse perception of HRQoL), especially in the psychological and role dimensions (range 52/100 to 55/100), but were closer to populational values in the physical and functional dimensions (range 61/100 to 75/100)). The highest correlation between MOS-SF-36 dimensions and HDS was found in the MOS-SF-36 "mental health" dimension (r=-.56, p < .001); this dimension was also correlated highly with the psychiatric dimension of the ASI (r=-.73, p < .001). The eight dimensions of the MOS-SF-36 were 21% to 127% lower in patients with HDS greater than or equal to 16 (major depression) compared to those with HDS less than or equal to 7 (absence of depression). The MOS-SF-36 dimensions were 10% to 141% lower in patients with high "ASI alcohol" scores, indicating worse HRQoL profiles with a higher severity of alcohol dependence. The MOS-SF-36 presents good criteria for reliability and validity in alcohol-dependent patients. The results suggested that alcohol-dependent patients perceived their problems more as psychological than physical. The severity of alcohol dependence and depression seemed to influence the perception of HRQoL negatively.
Resumo:
A plant species' genetic population structure is the result of a complex combination of its life history, ecological preferences, position in the ecosystem and historical factors. As a result, many different statistical methods exist that measure different aspects of species' genetic structure. However, little is known about how these methods are interrelated and how they are related to a species' ecology and life history. In this study, we used the IntraBioDiv amplified fragment length polymorphisms data set from 27 high-alpine species to calculate eight genetic summary statistics that we jointly correlate to a set of six ecological and life-history traits. We found that there is a large amount of redundancy among the calculated summary statistics and that there is a significant association with the matrix of species traits. In a multivariate analysis, two main aspects of population structure were visible among the 27 species. The first aspect is related to the species' dispersal capacities and the second is most likely related to the species' postglacial recolonization of the Alps. Furthermore, we found that some summary statistics, most importantly Mantel's r and Jost's D, show different behaviour than expected based on theory. We therefore advise caution in drawing too strong conclusions from these statistics.
Resumo:
Quality of life has been extensively discussed in acute and chronic illnesses. However a dynamic model grounded in the experience of patients in the course of transplantation has not been to our knowledge developed. In a qualitative longitudinal study, patients awaiting solid organ transplantation participated in semi-structured interviews: Exploring topics pre-selected on previous research literature review. Creative interview was privileged, open to themes patients would like to discuss at the different steps of the transplantation process. A qualitative thematic and reflexive analysis was performed, and a model of the dimensions constitutive of quality of life from the perspective of the patients was elaborated. Quality of life is not a stable construct in a long lasting illness-course, but evolves with illness constraints, treatments and outcomes. Dimensions constitutive of quality of life are defined, each of them containing different sub-categories depending on the organ related illness co-morbidities and the stage of illness-course.
Resumo:
BACKGROUND: NovoTTF is a portable device delivering low-intensity, intermediate-frequency, electric fields using noninvasive, disposable scalp electrodes. These fields physically interfere with cell division. Preliminary studies in recurrent and newly diagnosed glioblastoma (GBM) have shown promising results. A phase III study in recurrent GBM has recently been concluded. METHODS: Adults (KPS ≥ 70%) with recurrent GBM (any recurrence) were randomized (stratified by surgery and center) to either NovoTTF administered continuously (20-24 hours/day, 7 days/week) or the best available chemotherapy (best physician choice [BPC]). Primary endpoint was overall survival (OS); 6-month progression-free survival (PFS6), 1-year survival, and QOL were secondary endpoints. RESULTS: Two hundred thirty-seven patients were randomized (28 centers in the United States and Europe) to either NovoTTF alone (120 patients) or BPC (117 patients). Patient characteristics were balanced, median age was 54 years (range, 23-80 years), median KPS was 80% (range, 50-100). One quarter had surgery for recurrence, and over half were at their second or more recurrence. A survival advantage for the device group was seen in patients treated according to protocol (median OS, 7.8 months vs. 6.1 months; n = 185; p = 0.01). Moreover, subgroup analysis in patients with better prognostic baseline characteristics (KPS ≥ 80%; age ≤ 60; 1st-3rd recurrence) demonstrated a robust survival benefit for NovoTTF patients compared to matched BPC patients (median OS, 8.8 months vs. 6.6 months; n = 110; p < 0.01). In this group, 1-year survival was 35% vs. 20% and PFS6 was 25.6% vs. 7.7%. Interestingly, in patients who failed bevacizumab prior to the trial, OS was also significantly extended by NovoTTF (4.4 months vs. 3.1 months; n = 23 vs. n = 21; p < 0.02). Quality of life was equivalent or superior in NovoTTF patients. CONCLUSIONS: NovoTTF, a noninvasive, novel cancer treatment modality shows significant therapeutic efficacy with improved quality of life. The impact of NovoTTF was more pronounced when patients with better baseline prognostic factors were treated. A large scale phase III clinical trial in newly diagnosed GBM is currently being conducted.
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Despite intensive research efforts, the aetiology of the majority of chronic lung diseases (CLD) in both, children and adults, remains elusive. Current therapeutic options are limited, providing only symptomatic relief, rather than treating the underlying condition, or preventing its development in the first place. Thus, there is a strong and unmet clinical need for the development of both, novel effective therapies and preventative strategies for CLD. Many studies suggest that modifications of prenatal and/or early postnatal lung development will have important implications for future lung function and risk of CLD throughout life. This view represents a fundamental change of current pathophysiological concepts and treatment paradigms, and holds the potential to develop novel preventative and/or therapeutic strategies. However, for the successful development of such approaches, key questions, such as a clear understanding of underlying mechanisms of impaired lung development, the identification and validation of relevant preclinical models to facilitate translational research, and the development of concepts for correction of aberrant development, all need to be solved. Accordingly, a European Science Foundation Exploratory Workshop was held where clinical, translational and basic research scientists from different disciplines met to discuss potential mechanisms of developmental origins of CLD, and to identify major knowledge gaps in order to delineate a roadmap for future integrative research.
Resumo:
Sustainable resource use is one of the most important environmental issues of our times. It is closely related to discussions on the 'peaking' of various natural resources serving as energy sources, agricultural nutrients, or metals indispensable in high-technology applications. Although the peaking theory remains controversial, it is commonly recognized that a more sustainable use of resources would alleviate negative environmental impacts related to resource use. In this thesis, sustainable resource use is analysed from a practical standpoint, through several different case studies. Four of these case studies relate to resource metabolism in the Canton of Geneva in Switzerland: the aim was to model the evolution of chosen resource stocks and flows in the coming decades. The studied resources were copper (a bulk metal), phosphorus (a vital agricultural nutrient), and wood (a renewable resource). In addition, the case of lithium (a critical metal) was analysed briefly in a qualitative manner and in an electric mobility perspective. In addition to the Geneva case studies, this thesis includes a case study on the sustainability of space life support systems. Space life support systems are systems whose aim is to provide the crew of a spacecraft with the necessary metabolic consumables over the course of a mission. Sustainability was again analysed from a resource use perspective. In this case study, the functioning of two different types of life support systems, ARES and BIORAT, were evaluated and compared; these systems represent, respectively, physico-chemical and biological life support systems. Space life support systems could in fact be used as a kind of 'laboratory of sustainability' given that they represent closed and relatively simple systems compared to complex and open terrestrial systems such as the Canton of Geneva. The chosen analysis method used in the Geneva case studies was dynamic material flow analysis: dynamic material flow models were constructed for the resources copper, phosphorus, and wood. Besides a baseline scenario, various alternative scenarios (notably involving increased recycling) were also examined. In the case of space life support systems, the methodology of material flow analysis was also employed, but as the data available on the dynamic behaviour of the systems was insufficient, only static simulations could be performed. The results of the case studies in the Canton of Geneva show the following: were resource use to follow population growth, resource consumption would be multiplied by nearly 1.2 by 2030 and by 1.5 by 2080. A complete transition to electric mobility would be expected to only slightly (+5%) increase the copper consumption per capita while the lithium demand in cars would increase 350 fold. For example, phosphorus imports could be decreased by recycling sewage sludge or human urine; however, the health and environmental impacts of these options have yet to be studied. Increasing the wood production in the Canton would not significantly decrease the dependence on wood imports as the Canton's production represents only 5% of total consumption. In the comparison of space life support systems ARES and BIORAT, BIORAT outperforms ARES in resource use but not in energy use. However, as the systems are dimensioned very differently, it remains questionable whether they can be compared outright. In conclusion, the use of dynamic material flow analysis can provide useful information for policy makers and strategic decision-making; however, uncertainty in reference data greatly influences the precision of the results. Space life support systems constitute an extreme case of resource-using systems; nevertheless, it is not clear how their example could be of immediate use to terrestrial systems.
Resumo:
We modelled the future distribution in 2050 of 975 endemic plant species in southern Africa distributed among seven life forms, including new methodological insights improving the accuracy and ecological realism of predictions of global changes studies by: (i) using only endemic species as a way to capture the full realized niche of species, (ii) considering the direct impact of human pressure on landscape and biodiversity jointly with climate, and (iii) taking species' migration into account. Our analysis shows important promises for predicting the impacts of climate change in conjunction with land transformation. We have shown that the endemic flora of Southern Africa on average decreases with 41% in species richness among habitats and with 39% on species distribution range for the most optimistic scenario. We also compared the patterns of species' sensitivity with global change across life forms, using ecological and geographic characteristics of species. We demonstrate here that species and life form vulnerability to global changes can be partly explained according to species' (i) geographical distribution along climatic and biogeographic gradients, like climate anomalies, (ii) niche breadth or (iii) proximity to barrier preventing migration. Our results confirm that the sensitivity of a given species to global environmental changes depends upon its geographical distribution and ecological proprieties, and makes it possible to estimate a priori its potential sensitivity to these changes.
Resumo:
BACKGROUND: Hepatitis C virus (HCV) infection is associated with decreased health-related quality of life (HRQOL). Although HCV has been suggested to directly impair neuropsychiatric functions, other factors may also play a role. PATIENTS AND METHODS: In this cross-sectional study, we assessed the impact of various host-, disease- and virus-related factors on HRQOL in a large, unselected population of anti-HCV-positive subjects. All individuals (n = 1736) enrolled in the Swiss Hepatitis C Cohort Study (SCCS) were asked to complete the Short Form 36 (SF-36) and the Hospital Anxiety Depression Scale (HADS). RESULTS: 833 patients (48%) returned the questionnaires. Survey participants had significantly worse scores in both assessment instruments when compared to a general population. By multivariable analysis, reduced HRQOL (mental and physical summary scores of SF-36) was independently associated with income. In addition, a low physical summary score was associated with age and diabetes, whereas a low mental summary score was associated with intravenous drug use. HADS anxiety and depression scores were independently associated with income and intravenous drug use. In addition, HADS depression score was associated with diabetes. None of the SF-36 or HADS scores correlated with either the presence or the level of serum HCV RNA. In particular, SF-36 and HADS scores were comparable in 555 HCV RNA-positive and 262 HCV RNA-negative individuals. CONCLUSIONS: Anti-HCV-positive subjects have decreased HRQOL compared to controls. The magnitude of this decrease was clinically important for the SF-36 vitality score. Host and environmental, rather than viral factors, seem to impact on HRQOL level.