933 research outputs found
DO SAGEBRUSH DENSITY AND VEGETATION CONDITION AFFECT DEMOGRAPHY OF BREWER\u27S SPARROWS NESTING IN THE BLACKFOOT VALLEY?
Vegetation condition can influence habitat quality by altering food abundance, predator abundance and species composition, and microclimate. In some habitats, livestock grazing alters vegetation condition in ways that affect the breeding success of passerines. Most sagebrush-dominated habitats have been heavily grazed by livestock, and the total area of sagebrush has declined substantially. Owing to this habitat loss and change, numbers of various sagebrush-obligate birds have declined, the Brewer\u27s Sparrow among them. I examined the effects of cattle grazing on Brewer\u27s Sparrow reproduction. Grazed plots, at the study-site scale, were characterized by higher potential nest-sagebrush density, and canopy cover, a higher number of exotic grass species, greater bare/rock ground cover, and lower grass/forb ground cover, compared with ungrazed plots. Trends in the characteristics of vegetation at the nest-patch scale were the same as those at the study-site scale. Reproductive performance was similar between grazed and ungrazed plots. Nestlings raised on ungrazed plots were larger than those on grazed plots in 2004, but not in other years. The numbers of breeding pairs were, however, higher in grazed plots than in ungrazed plots.
Vegetation condition also influences nest-site selection of organisms. Many studies assume that this selection is adaptive; however, it does not necessarily increase the fecundity of organisms. Vegetation condition becomes one of the important cues to select nest sites because organisms use vegetation as nest hiding cover, thermal cover, foraging sites, and display sites. I examined two questions, using model selection analysis: (1) does vegetation condition affect nest survival of Brewer\u27s Sparrows?; and (2) does vegetation condition affect nestling size? There was no one best-approximating model to explain the correlation between vegetation features and nest survival, but all high-ranking models included nest-patch variables. In nestling-size models, nest-shrub size was positively correlated, and nest cover was negatively correlated, with nestling mass. Contrary to nest-survival models, nestling mass was strongly associated with nest-shrub variables rather than with nest-patch or understory-layer variables
Microscopic Observation of Tensile Deformation Behavior of Polycrystalline Titanium with Scanning Probe Microscope
The change in the surface morphology of polycrystalline titanium during tensile plastic deformation is studied, using the scanning probe microscope as well as the laser scanning microscope. The observation shows that the slip occurs mainly near grain boundary at the strain range of ε < 0.05. The slip develops with the applied strain, and the slip on the second slip system or the crossing of slip lines appear. The surface roughness increases linearly with the applied strain. The height difference between the
grain boundary area and the inner grain area also increases with the applied strain, though the increase rate becomes low after the applied strain of about 0.3. The nano-scale height difference of the surface step of slip lines increases with the applied strain, though it remains almost constant after the applied strain of 0.4. The averaged surface roughness measured with the scanning probe microscope is in good agreement with that measured with the laser scanning microscope
Idiopathic Retroperitoneal Hematoma
A 34-year-old female presented with sudden onset of severe abdominal pain in a flank distribution. A large mass was palpable in the right upper quadrant on physical examination. Abdominal contrast-enhanced computed tomography showed a well-defined, right-sided, retroperitoneal cystic lesion located between the abdominal aorta and the inferior vena cava (IVC). The tumor size was 55 × 58 mm, and it compressed the gallbladder and the duodenum. Upper gastrointestinal radiography revealed a stricture of the second portion of the duodenum by the tumor. T2-weighted magnetic resonance imaging showed that the whole part was hyperintense with hypointense rims, but the inner was partially hypointense. Based on the radiological findings, the preoperative differential diagnosis included retroperitoneal teratoma, Schwannoma, abscess, and primary retroperitoneal tumor. On laparotomy, the tumor was located in the right retroperitoneal cavity. Kocher maneuver and medial visceral rotation, which consists of medial reflection of the upper part of right colon and duodenum by incising their lateral peritoneal attachments, were performed. Although a slight adhesion to the IVC was detected, the tumor was removed safely. Thin-section histopathology examination detected neither tumor tissues nor any tissues such as adrenal gland, ovarian tissue, or endometrial implants. The final pathological diagnosis was idiopathic retroperitoneal hematoma; the origin of the bleeding was unclear. The patient was discharged without any complication 5 days after the operation
Electron Beam Cladding of Titanium on Stainless Steel Plate(Physics, Process, Instrument & Measurement)
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Cardiovascular Inflammation 2012: Reactive Oxygen Species, SUMOylation, and Biomarkers in Cardiovascular Inflammation
Uric acid is an independent risk factor for carotid atherosclerosis in a Japanese elderly population without metabolic syndrome
<p>Abstract</p> <p>Background</p> <p>Carotid intima-media thickness (IMT) is an useful surrogate marker of cardiovascular disease. Associations between uric acid (UA), metabolic syndrome (MetS) and carotid IMT have been reported, but findings regarding the relationship have been inconsistent.</p> <p>Methods</p> <p>A total of 1,579 Japanese elderly subjects aged ≥65 years {663 men aged, 78 ± 8 (mean ± standard deviation) years and 916 women aged 79 ± 8 years} were divided into 4 groups according to UA quartiles. We first investigated the association between UA concentrations and confounding factors including MetS; then, we assessed whether there is an independent association of UA with carotid IMT and atherosclerosis in participants subdivided according to gender and MetS status.</p> <p>Results</p> <p>Carotid IMT was significantly increased according to the quartiles of UA in both genders without MetS and women with MetS. Multivariate logistic regression analysis showed that odds ratio (OR) {95% confidence interval (CI)} in men for carotid atherosclerosis was significantly increased in the third (OR, 1.75; 95% CI, 1.02-3.02), and fourth quartiles (OR, 2.01; 95% CI, 1.12-3.60) of UA compared with that in the first quartile of UA, and the OR in women was significantly increased in the fourth quartile (OR, 2.10; 95% CI, 1.30-3.39). Similarly, the ORs were significantly associated with increasing quartiles of UA in both genders without MetS, but not necessarily increased in those with MetS.</p> <p>Conclusions</p> <p>UA was found to be an independent risk factor for incidence of carotid atherosclerosis in both genders without MetS.</p
Decreased levels of insulin-like growth factor-1 and vascular endothelial growth factor relevant to the ossification disturbance in femoral heads spontaneous hypertensive rats.
Ossification disturbance in femoral head reportedly is seen in the Spontaneously Hypertensive rats (SHR) between ages of 10 and 20 weeks. We investigated serum and tissue levels of insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF) in SHR relevant to the ossification disturbance and osteonecrosis of the femoral head. Serum levels of IGF-1 and VEGF were significantly lower in SHR than in Wistar Kyoto rats (WKY) at weeks 5, 10, 15 and 20 (p<0.005). The incidence of histological ossification disturbance of the femoral head was higher in SHR (59%) than in WKY (40%) at week 20. Lower serum and local levels of VEGF in SHR appeared to be related to the incomplete ossification of the femoral heads. Immunohistochemical study showed significantly lower numbers of IGF-1 and VEGF positive chondrocytes in the femoral epiphyseal cartilage of SHR than in those of WKY at weeks 10, 15 and 20. Our results suggest that local and/or systemic levels of IGF-1 and VEGF between ages of 5 and 20 weeks might play roles in the pathogenesis of ossifi cation disturbance of the femoral head in SHR
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