1,016 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
On the evolution of decoys in plant immune systems
The Guard-Guardee model for plant immunity describes how resistance proteins
(guards) in host cells monitor host target proteins (guardees) that are
manipulated by pathogen effector proteins. A recently suggested extension of
this model includes decoys, which are duplicated copies of guardee proteins,
and which have the sole function to attract the effector and, when modified by
the effector, trigger the plant immune response. Here we present a
proof-of-principle model for the functioning of decoys in plant immunity,
quantitatively developing this experimentally-derived concept. Our model links
the basic cellular chemistry to the outcomes of pathogen infection and
resulting fitness costs for the host. In particular, the model allows
identification of conditions under which it is optimal for decoys to act as
triggers for the plant immune response, and of conditions under which it is
optimal for decoys to act as sinks that bind the pathogen effectors but do not
trigger an immune response.Comment: 15 pages, 6 figure
Brief Measure for Screening Complicated Grief: Reliability and Discriminant Validity
BACKGROUND: Complicated grief, which is often under-recognized and under-treated, can lead to substantial impairment in functioning. The Brief Grief Questionnaire (BGQ) is a 5-item self-report or interview instrument for screening complicated grief. Although investigations with help-seeking samples suggest that the BGQ is valid and reliable, it has not been validated in a broader population. METHODOLOGY/PRINCIPAL FINDINGS: A questionnaire was mailed to a randomly selected sample (n = 5000) residing in one of 4 areas of Japan. The BCQ was examined for responders who were bereaved more than 6 months and less than 10 years (n = 915). Non-specific psychological distress was assessed with the K6 screening scale. Multiple group confirmatory factor analysis supported a uni-dimensional factor structure and the invariance of parameters across gender and age. Cronbach's alpha was sufficiently high (alpha = .75) to confirm internal consistency. Average Variance Extracted (0.39) was higher than the shared covariance (0.14) between BGQ and K6, suggesting discriminant validity. CONCLUSIONS: The results of this study support the reliability and validity of the BGQ in the Japanese population. Future studies should examine predictive validity by using structured interviews or more detailed scales for complicated grief
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
The efficacy and safety of pulse vs. continuous therapy for dermatophyte toenail onychomycosis
Background
Onychomycosis is a chronic, fungal infection of the nails. Complete cure remains challenging, but oral antifungal medications have been successful in managing the fungus for a significant proportion of patients. Treatment with these drugs can be continuous or intermittent, albeit the evidence on their relative efficacies remains unclear.
Objective
To determine the relative effectiveness and safety of pulse versus continuous administration, of three common oral therapies for dermatophyte onychomycosis, by conducting multiple‐treatment meta‐analysis.
Methods
This systematic review and network meta‐analysis compared the efficacy (as per mycological cure) and adverse event rates of three oral antifungal medications in the treatment of dermatophyte toenail onychomycosis, namely terbinafine, itraconazole and fluconazole. A total of 30 studies were included in the systematic review, while 22 were included in the network meta‐analysis.
Results
The likelihood of mycological cure was not significantly different between continuous and pulse regimens for each of terbinafine and itraconazole. Use of continuous terbinafine for 24 weeks – but not 12 weeks – was significantly more likely to result in mycological cure than continuous itraconazole for 12 weeks or weekly fluconazole for 9–12 months. Rank probabilities demonstrated that 24‐week continuous treatment of terbinafine was the most effective. There were no significant differences in the likelihood of adverse events between any continuous and pulse regimens of terbinafine, itraconazole and fluconazole. Drug treatments were similar to placebo in terms of their likelihood of producing adverse events.
Conclusion
More knowledge about the fungal life cycle and drugs’ pharmacokinetics in nail and plasma could further explain the relative efficacy and safety of the pulse and continuous treatment regimens. Our results indicate that in the treatment of dermatophyte toenail onychomycosis, the continuous and pulse regimens for terbinafine and itraconazole have similar efficacies and rates of adverse events
Erythropoietin Treatment in Traumatic Brain Injury: Operation Brain Trauma Therapy
Experimental studies targeting traumatic brain injury (TBI) have reported that erythropoietin (EPO) is an endogenous neuroprotectant in multiple models. In addition to its neuroprotective effects, it has also been shown to enhance reparative processes including angiogenesis and neurogenesis. Based on compelling pre-clinical data, EPO was tested by the Operation Brain Trauma Therapy (OBTT) consortium to evaluate therapeutic potential in multiple TBI models along with biomarker assessments. Based on the pre-clinical TBI literature, two doses of EPO (5000 and 10,000 IU/kg) were tested given at 15 min after moderate fluid percussion brain injury (FPI), controlled cortical impact (CCI), or penetrating ballistic-like brain injury (PBBI) with subsequent behavioral, histopathological, and biomarker outcome assessments. There was a significant benefit on beam walk with the 5000 IU dose in CCI, but no benefit on any other motor task across models in OBTT. Also, no benefit of EPO treatment across the three TBI models was noted using the Morris water maze to assess cognitive deficits. Lesion volume analysis showed no treatment effects after either FPI or CCI; however, with the 5000 IU/kg dose of EPO, a paradoxical increase in lesion volume and percent hemispheric tissue loss was seen after PBBI. Biomarker assessments included measurements of glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1) in blood at 4 or 24 h after injury. No treatment effects were seen on biomarker levels after FPI, whereas treatment at either dose exacerbated the increase in GFAP at 24 h in PBBI but attenuated 24-4 h delta UCH-L1 levels at high dose in CCI. Our data indicate a surprising lack of efficacy of EPO across three established TBI models in terms of behavioral, histopathological, and biomarker assessments. Although we cannot rule out the possibility that other doses or more prolonged treatment could show different effects, the lack of efficacy of EPO reduced enthusiasm for its further investigation in OBTT
Quantitative analysis of the epithelial lining architecture in radicular cysts and odontogenic keratocysts
BACKGROUND: This paper describes a quantitative analysis of the cyst lining architecture in radicular cysts (of inflammatory aetiology) and odontogenic keratocysts (thought to be developmental or neoplastic) including its 2 counterparts: solitary and associated with the Basal Cell Naevus Syndrome (BCNS). METHODS: Epithelial linings from 150 images (from 9 radicular cysts, 13 solitary keratocysts and 8 BCNS keratocysts) were segmented into theoretical cells using a semi-automated partition based on the intensity of the haematoxylin stain which defined exclusive areas relative to each detected nucleus. Various morphometrical parameters were extracted from these "cells" and epithelial layer membership was computed using a systematic clustering routine. RESULTS: Statistically significant differences were observed across the 3 cyst types both at the morphological and architectural levels of the lining. Case-wise discrimination between radicular cysts and keratocyst was highly accurate (with an error of just 3.3%). However, the odontogenic keratocyst subtypes could not be reliably separated into the original classes, achieving discrimination rates slightly above random allocations (60%). CONCLUSION: The methodology presented is able to provide new measures of epithelial architecture and may help to characterise and compare tissue spatial organisation as well as provide useful procedures for automating certain aspects of histopathological diagnosis
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
Storytelling in Amy Tan’s The bonesetter’s daughter: belonging and the transnationality of home in older age
Amy Tan’s The Bonesetter’s Daughter is a fictional account of a Chinese American woman and her mother, a first generation migrant, who is negotiating dementia in later life. Analysis of diasporic novels can provide insight into migrant belonging, especially the emotional geographies of home and emotional subjectivities of ageing that are not commonly or easily elucidated even by qualitative interviewing methods. This article examines Tan’s construction of ageing as an intergenerational, cultural and emotional process, and highlights the role of storytelling as an everyday home-making practice through which the transnationality of home in older age becomes evident
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