157 research outputs found

    Effects of patch size and basal area on avian taxonomic and functional diversity in pine forests: Implication for the influence of habitat quality on the speciesā€“area relationship

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    Relationships between avian diversity and habitat area are assumed to be positive; however, often little attention has given to how these relationships can be influenced by the habitat structure or quality. In addition, other components of biodiversity, such as functional diversity, are often overlooked in assessing habitat patch value. In the Sandhills Ecoregion of Georgia, USA, we investigated the relationship between avian species richness and functional diversity, forest basal area, and patch size in pine forests using basal area as a surrogate for overstory structure which in turn impacts vegetation structure and determines habitat quality within a patch. We conducted bird surveys in planted mature pine stands, during breeding season of 2011. We used three classes of stand basal area (BA): OS, overstocked (BA ā‰„ 23 m2/ha); FS, fully/densely stocked (13.8 m2/ha ā‰¤ BA \u3c 23 m2/ha); and MS, moderately stocked (2.3 m2/ha ā‰¤ BA \u3c 13.8 m2/ha). MS patches showed more structural diversity due to higher herbaceous vegetation cover than other two pine stocking classes of patches. Total species richness and functional richness increased with the size of MS patches, whereas functional divergence decreased with the size of OS patches (p \u3c 0.05). Functional richness tended to be lower than expected as the size of OS patches increased. Greater richness of pineā€“grassland species was also found at MS patches. Percent cover of MS patches within a landscape influenced positively the richness of pineā€“grassland species (p \u3c 0.05). Our results suggest that (a) avian speciesā€“habitat area relationship can be affected by habitat quality (structural diversity) and varies depending on diversity indices considered, and (b) it is important to maintain moderate or low levels of pine basal area and to preserve large-sized patches of the level of basal area to enhance both taxonomic and functional diversity in managed pine forests

    Avian taxonomic and functional diversity in early stage of longleaf pine (Pinus palustris) stands restored at agricultural lands: Variations in scale dependency

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    In agricultural landscapes, the Longleaf Pine Initiative (LLPI) and the Bobwhite Quail Initiative (BQI) aim to restore longleaf pine forests and early successional habitats, respectively. The early stage of longleaf pine stands and grass and forb vegetation produced by a combination of both restoration programs (LLPI-BQI) may form habitat conditions favorable to early successional bird species and other birds, increasing avian diversity. We investigated how the LLPI and BQI programs affected taxonomic and functional diversity of birds and abundance of early successional birds (grassland and scrub/shrub species), and what environmental characteristics were associated with the diversity and abundance of birds. Our study was performed at 41 fields in Georgia, USA, during 2001-2002 by considering environmental characteristics at two spatial scales: local-scale vegetation features and restoration program type (LLPI or LLPI-BQI) and landscape-scale vegetation features and landscape heterogeneity. Functional evenness, species richness, and abundance of grassland and scrub/shrub species did not show a clear association with local- or landscape-scale variables. Shannon-Wiener diversity was slightly influenced by restoration program type (local-scale variable) with higher value at LLPI-BQI stands than at LLPI stands despite no significant differences in local vegetation features between those stands. Functional divergence was strongly positively associated with landscape-scale variables. That is, niche differentiation increased with increasing shrub coverage within a landscape, reducing competition between abundant bird species and others. Our results suggest that although a combination of BQI and LLPI program may have a positive effect on avian taxonomic diversity, it is important to consider shrub vegetation cover within a landscape to improve functional diversity

    Avian taxonomic and functional diversity in early stage of longleaf pine (Pinus palustris) stands restored at agricultural lands: Variations in scale dependency

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    In agricultural landscapes, the Longleaf Pine Initiative (LLPI) and the Bobwhite Quail Initiative (BQI) aim to restore longleaf pine forests and early successional habitats, respectively. The early stage of longleaf pine stands and grass and forb vegetation produced by a combination of both restoration programs (LLPI-BQI) may form habitat conditions favorable to early successional bird species and other birds, increasing avian diversity. We investigated how the LLPI and BQI programs affected taxonomic and functional diversity of birds and abundance of early successional birds (grassland and scrub/shrub species), and what environmental characteristics were associated with the diversity and abundance of birds. Our study was performed at 41 fields in Georgia, USA, during 2001-2002 by considering environmental characteristics at two spatial scales: local-scale vegetation features and restoration program type (LLPI or LLPI-BQI) and landscape-scale vegetation features and landscape heterogeneity. Functional evenness, species richness, and abundance of grassland and scrub/shrub species did not show a clear association with local- or landscape-scale variables. Shannon-Wiener diversity was slightly influenced by restoration program type (local-scale variable) with higher value at LLPI-BQI stands than at LLPI stands despite no significant differences in local vegetation features between those stands. Functional divergence was strongly positively associated with landscape-scale variables. That is, niche differentiation increased with increasing shrub coverage within a landscape, reducing competition between abundant bird species and others. Our results suggest that although a combination of BQI and LLPI program may have a positive effect on avian taxonomic diversity, it is important to consider shrub vegetation cover within a landscape to improve functional diversity

    Value of Paraspinal Electromyography in the Evaluation of Thoracic Myelopathy

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    The authors have performed paraspinal needle EMG studies in twenty five patients with thoracic myelopathy. They were divided into demonstrable thoracic lesions and non-demonstrable thoracic lesions by neuroimaging studies resulting in 12 cases of the former and 13 cases of the latter. There were abnormal paraspinal EMG findings in 83% with demonstrable thoracic lesions. All five patients with thoracic disc diseases revealed abnormalities which indicated subsequent involvement of ventral roots by compressive lesions. In non-demonstrable thoracic lesions, the authors could demonstrate abnormal paraspinal EMGs in a relatively high percentage (62.5%) of preseumed and still occult thoracc myelopathy, but not in all four patients with demyelinating disease. Therefore it is concluded that paraspinal EMG studies are valuable in those patients wih thoracic myelopathy as a method of predicting he presumed nature of their causes and indicating the level of anticipated myelography or spinal CT. However, it was impossible to differentiate among patients with malignancy, those with thoracic disc diseases and those with unknown thoracic myelopathy by the paraspinal EMG studies

    Moxifloxacin: Clinically compatible contrast agent for multiphoton imaging

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    Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence.1152sciescopu

    Antihyperglycemic and Antioxidant Properties of Caffeic Acid in db/db

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    A Study on Selective Cerebellar Degeneration Following ,Ī²-Fluorethyl Acetate Poisoning

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    This is to report clinical and radiological findings in 7 patients with selective cerebellar degeneration following ,B-fluoroethyl acetate intoxication. ,B-Fluoroethyl acetate, an ethyl ester of fluoroacetate which is a metabolic inhibitor of Krebs cycle is used as a rodenticide. Following initial stage of coma from intoxication, the patients woke up to show selective cerebellar dysfunction, often so severe as not to be able to sit or stand unsupported. They improved gradually over several months to years with variable degrees of residual cerebellar dysfunction. Gait disturbance and dysarthria were the most prominent and persistent factors of the cerebellar dysfunction, whereas mild nystagmus was rarely seen. Cognitive function was not impaired. Cerebellar atrophy became noticeable on CT and MRI 4 weeks after poisoning, and progressed over time even with clinical improvement. Cerebellar degeneration contrasts with pallidal degeneration following carbon monoxide poisoning. ,B-Fluoroethyl acetate may be selectively toxic to the cerebellum

    The impact of urbanization on body size of Barn Swallows Hirundo rustica gutturalis

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    Urbanization implies a dramatic impact on ecosystems, which may lead to drastic phenotypic differences between urban and nonurban individuals. For instance, urbanization is associated with increased metabolic costs, which may constrain body size, but urbanization also leads to habitat fragmentation, which may favor increases in body mass when for instance it correlates with dispersal capacity. However, this apparent contradiction has rarely been studied. This is particularly evident in China where the urbanization process is currently occurring at an unprecedented scale. Moreover, no study has addressed this issue across large geographical areas encompassing locations in different climates. In this regard, Barn Swallows (Hirundo rustica) are a suitable model to study the impact of urbanization on wild animals because they are a widely distributed species tightly associated with humans. Here, we collected body mass and wing length data for 359 breeding individuals of Barn Swallow (H. r. gutturalis) from 128 sites showing different levels of urbanization around the whole China. Using a set of linear mixed-effects models, we assessed how urbanization and geography influenced body size measured using body mass, wing length, and their regression residuals. Interestingly, we found that the impact of urbanization was sex-dependent, negatively affecting malesā€™ body mass, its regression residuals, and femalesā€™ wing length. We also found that northern and western individuals were larger, regarding both body mass and wing length, than southern and eastern individuals. Females were heavier than males, yet males had slightly longer wings than females. Overall, our results showed that body mass of males was particularly sensitive trait to urbanization, latitude, and longitude, while it only showed a weak response to latitude in females. Conversely, while wing length showed a similar geographical pattern, it was only affected by urbanization in the case of females. Further research is needed to determine whether these phenotypic differences are associated with negative effects of urbanization or potential selective advantages
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