67 research outputs found
Ecological assessment of an intermitent Mediterranean river using community structure and function: evaluating the role of different organism groups
1. Reliable lotic ecological monitoring requires knowledge of river typology, environmental
factors, the effect of stressors known here as âpressuresâ and appropriate indicators
of anthropogenically induced change. We sampled benthic macroinvertebrate, fish, bird
and macrophyte communities along an intermittent Mediterranean river and analysed
community structure (relative abundance) and function (metrics) relative to environmental
and pressure gradients in order to identify suitable indicator group(s) for future
monitoring and mitigation programmes.
2. Principal components analysis revealed that scale-dependent longitudinal differences in
valley form separated narrower higher lying sites and tributaries with good quality
habitats from more open degraded sites lower down the river continuum on a small
floodplain and large scale pressures describing changes in land use related to agriculture
with associated physical bankside and channel impacts.
3. Forward selection of variables in redundancy analysis (RDA) showed that reach scale
environmental variables were selected more frequently than pressure variables for each
organism group. Altitude and pH were highly redundant within and between groups,
indicating essentially longitudinal structural and functional distribution patterns. Redundancy
was far lower between selected pressure variables, but single or no pressure
variables were retained for some organism groups indicating poor association of
functional data, in particular, with the identified pressures. All RDA results indicated a
longitudinal pH gradient, highlighting the combined effect of multiple environmental and
pressure based mechanisms on organism groups.
4. Large, mobile organisms such as fish and birds provided a reliable link between
organism structure and function, environmental factors and physical disturbance of the
channel, bankside and wider river corridor. Benthic macroinvertebrate and macrophyte
structural data revealed distribution patterns in relation to water velocity, a key parameter
for developing appropriate compensation measures.
5. Results clearly show the importance of assessing patterns of both functional and
structural change across multiple organism groups in order to identify typologically appropriate links with complex environmental and pressure gradients and develop and
implement appropriate monitoring system
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Ten-year assessment of the 100 priority questions for global biodiversity conservation
In 2008, a group of conservation scientists compiled a list of 100 priority questions for the conservation of the world's biodiversity ?Sutherland et al. (2009) Conservation Biology, 23, 557?567?. However, now almost a decade later, no one has yet published a study gauging how much progress has been made in addressing these 100 high?priority questions in the peer?reviewed literature. Here we take a first step toward re?examining the 100 questions and identify key knowledge gaps that still remain. Through a combination of a questionnaire and a literature review, we evaluated each of the 100 questions on the basis of two criteria: relevance and effort. We defined highly?relevant questions as those which ? if answered ? would have the greatest impact on global biodiversity conservation, while effort was quantified based on the number of review publications addressing a particular question, which we used as a proxy for research effort. Using this approach we identified a set of questions that, despite being perceived as highly relevant, have been the focus of relatively few review publications over the past ten years. These questions covered a broad range of topics but predominantly tackled three major themes: the conservation and management of freshwater ecosystems, the role of societal structures in shaping interactions between people and the environment, and the impacts of conservation interventions. We see these questions as important knowledge gaps that have so far received insufficient attention and may need to be prioritised in future research
Body Composition, Symptoms, and Survival in Advanced Cancer Patients Referred to a Phase I Service
Background: Body weight and body composition are relevant to the outcomes of cancer and antineoplastic therapy. However, their role in Phase I clinical trial patients is unknown. Methods: We reviewed symptom burden, body composition, and survival in 104 patients with advanced cancer referred to a Phase I oncology service. Symptom burden was analyzed using the MD Anderson Symptom Assessment Inventory(MDASI); body composition was evaluated utilizing computerized tomography(CT) images. A body mass index (BMI)25 kg/m 2. Sarcopenic patients were older and less frequently African-American. Symptom burden did not differ among patients classified according to BMI and presence of sarcopenia. Median (95% confidence interval) survival (days) varied according to body composition: 215 (71â358) (BMI,25 kg/m 2; sarcopenic), 271 (99â443) (BMI,25 kg/m 2; non-sarcopenic), 484 (286â681) (BMI25 kg/m 2; non-sarcopenic). Higher muscle index and gastrointestinal cancer diagnosis predicted longer survival in multivariate analysis after controlling for age, gender, performance status, and fat index. Conclusions: Patients referred to a Phase I clinic had a high frequency of sarcopenia and a BMI$25 kg/m 2, independent o
Interaction of climate change with effects of conspecific and heterospecific density on reproduction
We studied the relationship between temperature and the coexistence of great titParus majorand blue titCyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a reduction in clutch size during warmer winters due to density-dependent effects. As expected, as spring temperature increases laying date advances and as winter temperature increases clutch size is reduced in both species. Density of great tit affected the relationship between winter temperature and laying date in great and blue tit. Specifically, as density of great tit increased and temperature in winter increased both species started to reproduce later. Density of blue tit affected the relationship between spring temperature and blue and great tit laying date. Thus, both species start to reproduce earlier with increasing spring temperature as density of blue tit increases, which was not an expected outcome, since we expected that increasing spring temperature should advance laying date, while increasing density should delay it cancelling each other out. Climate warming and its interaction with density affects clutch size of great tits but not of blue tits. As predicted, great tit clutch size is reduced more with density of blue tits as temperature in winter increases. The relationship between spring temperature and density on clutch size of great tits depends on whether the increase is in density of great tit or blue tit. Therefore, an increase in temperature negatively affected the coexistence of blue and great tits differently in both species. Thus, blue tit clutch size was unaffected by the interaction effect of density with temperature, while great tit clutch size was affected in multiple ways by these interactions terms.Peer reviewe
Prognostic gene expression signature for high-grade serous ovarian cancer.
BACKGROUND: Median overall survival (OS) for women with high-grade serous ovarian cancer (HGSOC) is âŒ4 years, yet survival varies widely between patients. There are no well-established, gene expression signatures associated with prognosis. The aim of this study was to develop a robust prognostic signature for OS in patients with HGSOC. PATIENTS AND METHODS: Expression of 513 genes, selected from a meta-analysis of 1455 tumours and other candidates, was measured using NanoString technology from formalin-fixed paraffin-embedded tumour tissue collected from 3769 women with HGSOC from multiple studies. Elastic net regularization for survival analysis was applied to develop a prognostic model for 5-year OS, trained on 2702 tumours from 15 studies and evaluated on an independent set of 1067 tumours from six studies. RESULTS: Expression levels of 276 genes were associated with OS (false discovery rate < 0.05) in covariate-adjusted single-gene analyses. The top five genes were TAP1, ZFHX4, CXCL9, FBN1 and PTGER3 (P < 0.001). The best performing prognostic signature included 101 genes enriched in pathways with treatment implications. Each gain of one standard deviation in the gene expression score conferred a greater than twofold increase in risk of death [hazard ratio (HR) 2.35, 95% confidence interval (CI) 2.02-2.71; P < 0.001]. Median survival [HR (95% CI)] by gene expression score quintile was 9.5 (8.3 to -), 5.4 (4.6-7.0), 3.8 (3.3-4.6), 3.2 (2.9-3.7) and 2.3 (2.1-2.6) years. CONCLUSION: The OTTA-SPOT (Ovarian Tumor Tissue Analysis consortium - Stratified Prognosis of Ovarian Tumours) gene expression signature may improve risk stratification in clinical trials by identifying patients who are least likely to achieve 5-year survival. The identified novel genes associated with the outcome may also yield opportunities for the development of targeted therapeutic approaches
Breaking Functional Connectivity into Components: A Novel Approach Using an Individual-Based Model, and First Outcomes
Landscape connectivity is a key factor determining the viability of populations in fragmented landscapes. Predicting âfunctional connectivityâ, namely whether a patch or a landscape functions as connected from the perspective of a focal species, poses various challenges. First, empirical data on the movement behaviour of species is often scarce. Second, animal-landscape interactions are bound to yield complex patterns. Lastly, functional connectivity involves various components that are rarely assessed separately. We introduce the spatially explicit, individual-based model FunCon as means to distinguish between components of functional connectivity and to assess how each of them affects the sensitivity of species and communities to landscape structures. We then present the results of exploratory simulations over six landscapes of different fragmentation levels and across a range of hypothetical bird species that differ in their response to habitat edges. i) Our results demonstrate that estimations of functional connectivity depend not only on the response of species to edges (avoidance versus penetration into the matrix), the movement mode investigated (home range movements versus dispersal), and the way in which the matrix is being crossed (random walk versus gap crossing), but also on the choice of connectivity measure (in this case, the model output examined). ii) We further show a strong effect of the mortality scenario applied, indicating that movement decisions that do not fully match the mortality risks are likely to reduce connectivity and enhance sensitivity to fragmentation. iii) Despite these complexities, some consistent patterns emerged. For instance, the ranking order of landscapes in terms of functional connectivity was mostly consistent across the entire range of hypothetical species, indicating that simple landscape indices can potentially serve as valuable surrogates for functional connectivity. Yet such simplifications must be carefully evaluated in terms of the components of functional connectivity they actually predict
Interspecific variation in the relationship between clutch size, laying date and intensity of urbanization in four species of hole-nesting birds
The increase in size of human populations in urban and agricultural areas has resulted in considerable habitat conversion globally. Such anthropogenic areas have specific environmental characteristics, which influence the physiology, life history, and population dynamics of plants and animals. For example, the date of bud burst is advanced in urban compared to nearby natural areas. In some birds, breeding success is determined by synchrony between timing of breeding and peak food abundance. Pertinently, caterpillars are an important food source for the nestlings of many bird species, and their abundance is influenced by environmental factors such as temperature and date of bud burst. Higher temperatures and advanced date of bud burst in urban areas could advance peak caterpillar abundance and thus affect breeding phenology of birds. In order to test whether laying date advance and clutch sizes decrease with the intensity of urbanization, we analyzed the timing of breeding and clutch size in relation to intensity of urbanization as a measure of human impact in 199 nest box plots across Europe, North Africa, and the Middle East (i.e., the Western Palearctic) for four species of hole-nesters: blue tits (Cyanistes caeruleus), great tits (Parus major), collared flycatchers (Ficedula albicollis), and pied flycatchers (Ficedula hypoleuca). Meanwhile, we estimated the intensity of urbanization as the density of buildings surrounding study plots measured on orthophotographs. For the four study species, the intensity of urbanization was not correlated with laying date. Clutch size in blue and great tits does not seem affected by the intensity of urbanization, while in collared and pied flycatchers it decreased with increasing intensity of urbanization. This is the first large-scale study showing a species-specific major correlation between intensity of urbanization and the ecology of breeding. The underlying mechanisms for the relationships between life history and urbanization remain to be determined. We propose that effects of food abundance or quality, temperature, noise, pollution, or disturbance by humans may on their own or in combination affect laying date and/or clutch size
Critical Histories of Archaeological Practice: Latin American and North American Interpretations in a Honduran Context
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