397 research outputs found

    Ceratoscopelus maderensis : pecular sound-scattering layer identified with this myctophid fish

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    Reprint. Science, vol. 160, no. 3831, 1968, pp. 991-993. Originally issued as Reference No. 68-58, series later renamed WHOI-.A sound- scattering layer, composed of discrete hyperbolic echo-sequences and apparently restricted to the Slope Water region of the western North Atlantic, has been identified from the Deep Submergence Research Vehicle ALVIN with schools of the myctophid fish Ceratoscopelus maderensis. By diving into the layer and using ALVIN's echo-ranging sonar, we approached and visually identified the sound scatterers. The number of echo sequences observed with the surface echo-sounder (1 /23. 76 x 105 cubic meters of water) checked roughly with the number of sonar targets observed from the submarine (1/7. 45 x 105 cubic meters) . The fish schools appeared to be 5 to 10 meters thick, 10 to 100 meters in diameter, and on centers 100 to 200 meters apart. Density within schools was estimated at 10 to 15 fish per cubic meter.Supported in part by contracts Nonr-3484(00) and Nonr-4029(00) and by NSF grant GB-4431

    Slow Relaxation of Spin Structure in Exotic Ferromagnetic Phase of Ising-like Heisenberg Kagome Antiferromagnets

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    In the corner-sharing lattice, magnetic frustration causes macroscopic degeneracy in the ground state, which prevents systems from ordering. However, if the ensemble of the degenerate configuration has some global structure, the system can have a symmetry breaking phenomenon and thus posses a finite temperature phase transition. As a typical example of such cases, the magnetic phase transition of the Ising-like Heisenberg antiferromagnetic model on the kagome lattice has been studied. There, a phase transition of the two-dimensional ferromagnetic Ising universality class occurs accompanying with the uniform spontaneous magnetization. Because of the macroscopic degeneracy in the ordered phase, the system is found to show an entropy-driven ordering process, which is quantitatively characterized by the number of ``weathervane loop''. We investigate this novel type of slow relaxation in regularly frustrated system.Comment: 4 pages, 6 figure

    Quantification of juvenile hormone III, vitellogenin, and vitellogenin-mRNA during the oviposition cycle of the lubber grasshopper

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    Abstract The vitellogenic cycle of the lubber grasshopper (Romalea microptera) was studied by measuring levels of juvenile hormone (JH III), vitellogenin, and vitellogenin-mRNA through the first oviposition cycle. JH III and vitellogenin were measured by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA), respectively. To measure vitellogenin-mRNA, a partial (753 bp) cDNA fragment of vitellogenin was isolated from the fat body of vitellogenic animals. The sequence of this cDNA was related to vitellogenin sequences in other insect species. Using these sequence data, an RT-PCR (reverse transcriptase polymerase chain reaction) assay was developed to quantify vitellogenin-mRNA levels during the oviposition cycle. Vitellogenin-mRNA levels in the fat body tissue from virgin females were measured on specific days after eclosion and compared to hemolymph levels of JH III and vitellogenin from the same individuals. The levels of all three compounds (JH III, vitellogenin, and vitellogenin-mRNA) showed similar changes throughout the oviposition cycle, being undetectable or nearly undetectable initially (day 3), rising to maximum levels on days 23 and 28, and then dropped to lower or undetectable levels on the day of oviposition. The ability to measure these characteristics will be useful for studying the effects of hormonal and nutritional manipulations on reproduction

    Family Caregiver Perspectives on Symptoms and Treatments for Patients Dying From Complications of Cystic Fibrosis

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    Most patients with advanced cystic fibrosis (CF) die from respiratory failure and experience distressing symptoms as lung disease progresses. Little has been reported about symptom management and the continuation of disease-specific treatments near the end of life for patients with CF

    Caregiver Perspectives on Discussions About the Use of Intensive Treatments in Cystic Fibrosis

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    Intensive treatments intended to sustain life are often used for patients with advanced cystic fibrosis (CF). There are no guidelines for selecting patients whose survival and quality of life may be enhanced by such treatments or for communication with patients and caregivers about possible treatment outcomes

    Caregivers' Perspectives on Decision Making about Lung Transplantation in Cystic Fibrosis

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    Lung transplantation extends survival for some patients with advanced cystic fibrosis, but it is complicated, has many potential risks, and its outcomes are difficult to predict. No standards exist for informed decision making about transplantation

    Mortality in Hepatitis C Virus–Infected Patients With a Diagnosis of AIDS in the Era of Combination Antiretroviral Therapy

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    Chronic hepatitis C increased mortality by approximately 50% in patients with Centers for Disease Control and Prevention–defined AIDS, despite the competing mortality risks in these patients. About 20% of the deaths were liver-related, suggesting that greater hepatitis C virus awareness and treatment could increase survival

    Ablation of the androgen receptor from vascular smooth muscle cells demonstrates a role for testosterone in vascular calcification

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    Vascular calcification powerfully predicts mortality and morbidity from cardiovascular disease. Men have a greater risk of cardiovascular disease, compared to women of a similar age. These gender disparities suggest an influence of sex hormones. Testosterone is the primary and most well-recognised androgen in men. Therefore, we addressed the hypothesis that exogenous androgen treatment induces vascular calcification. Immunohistochemical analysis revealed expression of androgen receptor (AR) in the calcified media of human femoral artery tissue and calcified human valves. Furthermore, in vitro studies revealed increased phosphate (Pi)-induced mouse vascular smooth muscle cell (VSMC) calcification following either testosterone or dihydrotestosterone (DHT) treatment for 9 days. Testosterone and DHT treatment increased tissue non-specific alkaline phosphatase (Alpl) mRNA expression. Testosterone-induced calcification was blunted in VSMC-specific AR-ablated (SM-ARKO) VSMCs compared to WT. Consistent with these data, SM-ARKO VSMCs showed a reduction in Osterix mRNA expression. However, intriguingly, a counter-intuitive increase in Alpl was observed. These novel data demonstrate that androgens play a role in inducing vascular calcification through the AR. Androgen signalling may represent a novel potential therapeutic target for clinical intervention

    Patterns of care in older patients with squamous cell carcinoma of the head and neck: A Surveillance, Epidemiology, and End Results-Medicare analysis

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    There is growing evidence in the literature that older patients may not benefit from more intensive therapy for Head and Neck Squamous Cell Carcinoma (HNSCC). A growing number of patients with Head and Neck Squamous Cell Carcinoma (HNSCC) are age 65 and older; however, much of the evidence base informing treatment decisions is based on substantially younger and healthier clinical trial populations. The purpose of this study was to assess the patterns of care of older HNSCC patients to better understand how age is associated with treatment decision

    Unique Phase Transition on Spin-2 Triangular Lattice of Ag2MnO2

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    Ag2MnO2 is studied as a possible candidate compound for an antiferromagnetic XY spin model on a triangular lattice. In spite of the large Curie-Weiss temperature of -430 K found in magnetic susceptibi-lity, Mn3+ spins with S = 2 do not undergo a conventional long-range order down to 2 K probably owing to the geometrical frustration and two dimensionality in the system. Instead, a unique phase transition is found at 80 K, where specific heat exhibits a clear sign of a second-order phase transition, while magnetic susceptibility changes smoothly without a distinct anomaly. We think that this transition is related to the chirality degree of freedom associated with a short-range order, which has been expected for the classical XY spin model on a triangular lattice. On further cooling, spin-glass-like behavior is observed below 22 K, possibly corresponding to a quasi-long-range order.Comment: to appear in J. Phys. Soc. Jpn, Vol. 77, No.
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