766 research outputs found
Sparse Distribution Pattern Of Some Plant Species In Two Afromontane Rain Forests Of The Eastern Arc Mountains Of Tanzania
Mountain forests play major roles in biodiversity; containing many endemics and species of conservation concern. The diversity and distribution patterns of plants in mountain ecosystems are influenced by various environmental and anthropogenic factors that exhibit heterogeneity over space and time. This study analysed species diversity and distribution patterns on two afromontane rain forests of the eastern Arc Mountains of Tanzania in the west Usambaras and Ulugurus to assess any possible threats to biodiversity conservation in this region. A hundred sample plots (0.02 ha) were established on each of the two mountain ranges in such a way as to cover as much variations as possible from valley bottoms to ridge tops. The analysis was based on species importance values computed from the average of the relative basal area and relative density as well as species frequency. Using different diversity indices, the study showed that the mountains have high species diversity. Eighteen endemic species were identified in the Usambaras and thirty-two in the Ulugurus. These endemics are fairly shared between the two mountains and other mountain massifs of the Eastern Arc. Based on our analysis of species distribution, it was found that the proportion of sparsely (rarely) distributed species was over 30% and 49% for the woody species and total vascular plants, respectively. These findings are important in alerting on possible decline of biodiversity in the region and prompting the development of policies to address rare, threatened, and endangered plant species, which are non-existence in Tanzania. We suggest further surveys in the forests of the Eastern Arc Mountains to determine whether the apparently sparse distribution of some species may be found in reasonable abundances elsewhere and quantify the manner and type of use of the forest resources by surrounding local communities to determine their possible impacts on species distribution. TJFNC Vol. 75 2004: pp. 74-9
Ordinal-Level Phylogenomics of the Arthropod Class Diplopoda (Millipedes) Based on an Analysis of 221 Nuclear Protein-Coding Loci Generated Using Next-Generation Sequence Analyses
Background
The ancient and diverse, yet understudied arthropod class Diplopoda, the millipedes, has a muddled taxonomic history. Despite having a cosmopolitan distribution and a number of unique and interesting characteristics, the group has received relatively little attention; interest in millipede systematics is low compared to taxa of comparable diversity. The existing classification of the group comprises 16 orders. Past attempts to reconstruct millipede phylogenies have suffered from a paucity of characters and included too few taxa to confidently resolve relationships and make formal nomenclatural changes. Herein, we reconstruct an ordinal-level phylogeny for the class Diplopoda using the largest character set ever assembled for the group.
Methods
Transcriptomic sequences were obtained from exemplar taxa representing much of the diversity of millipede orders using second-generation (i.e., next-generation or high-throughput) sequencing. These data were subject to rigorous orthology selection and phylogenetic dataset optimization and then used to reconstruct phylogenies employing Bayesian inference and maximum likelihood optimality criteria. Ancestral reconstructions of sperm transfer appendage development (gonopods), presence of lateral defense secretion pores (ozopores), and presence of spinnerets were considered. The timings of major millipede lineage divergence points were estimated.
Results
The resulting phylogeny differed from the existing classifications in a number of fundamental ways. Our phylogeny includes a grouping that has never been described (Juliformia+Merocheta+Stemmiulida), and the ancestral reconstructions suggest caution with respect to using spinnerets as a unifying characteristic for the Nematophora. Our results are shown to have significantly stronger support than previous hypotheses given our data. Our efforts represent the first step toward obtaining a well-supported and robust phylogeny of the Diplopoda that can be used to answer many questions concerning the evolution of this ancient and diverse animal group
Einstein equations in the null quasi-spherical gauge
The structure of the full Einstein equations in a coordinate gauge based on
expanding null hypersurfaces foliated by metric 2-spheres is explored. The
simple form of the resulting equations has many applications -- in the present
paper we describe the structure of timelike boundary conditions; the matching
problem across null hypersurfaces; and the propagation of gravitational shocks.Comment: 12 pages, LaTeX (revtex, amssymb), revision 18 pages, contains
expanded discussion and explanations, updated references, to appear in CQ
Step-wise evolution of complex chemical defenses in millipedes: a phylogenomic approach
With fossil representatives from the Silurian capable of respiring atmospheric oxygen, millipedes
are among the oldest terrestrial animals, and likely the first to acquire diverse and complex chemical defenses against predators. Exploring the origin of complex adaptive traits is critical for understanding the evolution of Earth’s biological complexity, and chemical defense evolution serves as an ideal
study system. The classic explanation for the evolution of complexity is by gradual increase from simple to complex, passing through intermediate “stepping stone� states. Here we present the first phylogenetic-based study of the evolution of complex chemical defenses in millipedes by generating the largest genomic-based phylogenetic dataset ever assembled for the group. Our phylogenomic results demonstrate that chemical complexity shows a clear pattern of escalation through time. New pathways are added in a stepwise pattern, leading to greater chemical complexity, independently in a number of derived lineages. This complexity gradually increased through time, leading to the advent of three distantly related chemically complex evolutionary lineages, each uniquely characteristic of each of the respective millipede groups
Neurospora from natural populations: Population genomics insights into the Life history of a model microbial Eukaryote
The ascomycete filamentous fungus Neurospora crassa played a historic role in experimental biology and became a model system for genetic research. Stimulated by a systematic effort to collect wild strains initiated by Stanford geneticist David Perkins, the genus Neurospora has also become a basic model for the study of evolutionary processes, speciation, and population biology. In this chapter, we will first trace the history that brought Neurospora into the era of population genomics. We will then cover the major contributions of population genomic investigations using Neurospora to our understanding of microbial biogeography and speciation, and review recent work using population genomics and genome-wide association mapping that illustrates the unique potential of Neurospora as a model for identifying the genetic basis of (potentially adaptive) phenotypes in filamentous fungi. The advent of population genomics has contributed to firmly establish Neurospora as a complete model system and we hope our review will entice biologists to include Neurospora in their research
Out of the wave: The meaning of suffering and relief from suffering as described in autobiographies by survivors of the 2004 Indian Ocean tsunami
The aim of this study was to explore the meaning of suffering and relief from suffering as described in autobiographies by tourists who experienced the tsunami on 26 December 2004 and lost loved ones. A lifeworld approach, inspired by the French philosopher Merleau-Ponty's phenomenology of perception, was chosen for the theoretical framework. This catastrophe totally changed the survivors' world within a moment. In this new world, there were three main phases: the power of remaining focused, a life of despair, and the unbearable becoming bearable. Life turns into a matter of making the unbearable bearable. Such challenging experiences are discussed in terms of the philosophy of Weil, Jaspers, and Merleau-Ponty. The survivors of the tsunami catastrophe were facing a boundary situation and “le malheur,” the unthinkable misfortune. Even at this lowest level of misfortune, joy is possible to experience. This is part of the survivors' ambivalent experiences of their lifeworld. In this world of the uttermost despair there are also rays of hope, joy, and new life possibilities
An adaptive virtual reality system for the treatment of adjustment disorder and complicated grief: 1‐year follow‐up efficacy data
This is the pre-peer reviewed version of the following article: An adaptive virtual reality system for the treatment of adjustment disorder and complicated grief: 1‐year follow‐up efficacy data, which has been published in final form at https://doi.org/10.1002/cpp.2342. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Adjustment disorder (AD) and complicated grief (CG) are serious mental conditions that have a high prevalence and are associated with significant impairments in social and work functioning. Recently, these categories have been better specified in the new ICD‐11 proposal. Empirical research on the efficacy of treatments for these problems is scarce. This study aims to offer long‐term efficacy data from a between‐groups controlled study that compares two treatment conditions (AD‐protocol applied in a traditional way: N = 18 and the same protocol supported by virtual reality (VR); VR‐protocol applied in a traditional way: N = 18) and a waiting list (WL) control group (N = 18). Both treatment conditions resulted in statistically significant improvements on both primary and secondary outcome measures, with large effect sizes, and this improvement did not occur in the WL. These changes were maintained in both treatment conditions in the medium (6‐month) and long‐term (12‐month follow‐up). Larger effect sizes were achieved in the VR condition in the long term. Furthermore, clinically significant change estimations on the primary outcome measures showed an advantage for the VR condition This is the first controlled study to compare a traditional face‐to‐face protocol for the treatment of stress‐related disorders with the same protocol supported by VR and a WL control group
108 AUROTHIOMALATE INHIBITS COX-2 EXPRESSION AND PGE2 PRODUCTION IN CHONDROCYTES BY INCREASING MKP-1 EXPRESSION AND DECREASING p38 AND JNK PHOSPHORYLATION
The very high occurrence of cardiovascular events presents a major public health issue, because treatment remains suboptimal. Lowering LDL cholesterol (LDL-C) with statins or ezetimibe in combination with a statin reduces major adverse cardiovascular events. The cardiovascular risk reduction in relation to the absolute LDL-C reduction is linear for most interventions without evidence of attenuation or increase in risk at low LDL-C levels. Opportunities for innovation in dyslipidaemia treatment should address the substantial risk of lipid-associated cardiovascular events among patients optimally treated per guidelines but who cannot achieve LDL-C goals and who could benefit from additional LDL-C-lowering therapy or experience side effects of statins. Fresh approaches are needed to identify promising drug targets early and develop them efficiently. The Cardiovascular Round Table of the European Society of Cardiology (ESC) convened a workshop to discuss new lipid-lowering strategies for cardiovascular risk reduction. Opportunities to improve treatment approaches and the efficient study of new therapies were explored. Circulating biomarkers may not be fully reliable proxy indicators of the relationship between treatment effect and clinical outcome. Mendelian randomization studies may better inform development strategies and refine treatment targets before Phase 3. Trials should match the drug to appropriate lipid and patient profile, and guidelines may move towards a precision-based approach to individual patient management. Stakeholder collaboration is needed to ensure continued innovation and better international coordination of both regulatory aspects and guidelines. It should be noted that risk may also be addressed through increased attention to other risk factors such as smoking, hypertension, overweight, and inactivity
A population study comparing screening performance of prototypes for depression and anxiety with standard scales
<p>Abstract</p> <p>Background</p> <p>Screening instruments for mental disorders need to be short, engaging, and valid. Current screening instruments are usually questionnaire-based and may be opaque to the user. A prototype approach where individuals identify with a description of an individual with typical symptoms of depression, anxiety, social phobia or panic may be a shorter, faster and more acceptable method for screening. The aim of the study was to evaluate the accuracy of four new prototype screeners for predicting depression and anxiety disorders and to compare their performance with existing scales.</p> <p>Methods</p> <p>Short and ultra-short prototypes were developed for Major Depressive Disorder (MDD), Generalised Anxiety Disorder (GAD), Panic Disorder (PD) and Social Phobia (SP). Prototypes were compared to typical short and ultra-short self-report screening scales, such as the Centre for Epidemiology Scale, CES-D and the GAD-7, and their short forms. The Mini International Neuropsychiatric Interview (MINI) version 6 <abbrgrp><abbr bid="B1">1</abbr></abbrgrp> was used as the gold standard for obtaining clinical criteria through a telephone interview. From a population sample, 225 individuals who endorsed a prototype and 101 who did not were administered the MINI. Receiver operating characteristic (ROC) curves were plotted for the short and ultra short prototypes and for the short and ultra short screening scales.</p> <p>Results</p> <p>The study found that the rates of endorsement of the prototypes were commensurate with prevalence estimates. The short-form and ultra short scales outperformed the short and ultra short prototypes for every disorder except GAD, where the GAD prototype outperformed the GAD 7.</p> <p>Conclusions</p> <p>The findings suggest that people may be able to self-identify generalised anxiety more accurately than depression based on a description of a prototypical case. However, levels of identification were lower than expected. Considerable benefits from this method of screening may ensue if our prototypes can be improved for Major Depressive Disorder, Social Phobia and Panic Disorder.</p
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