3,147 research outputs found

    Supersolid and solitonic phases in one-dimensional Extended Bose-Hubbard model

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    We report our findings on quantum phase transitions in cold bosonic atoms in a one dimensional optical lattice using the finite size density matrix renormalization group method in the framework of the extended Bose-Hubbard model. We consider wide ranges of values for the filling factors and the nearest neighbor interactions. At commensurate fillings, we obtain two different types of charge density wave phases and a Mott insulator phase. However, departure from commensurate fillings yield the exotic supersolid phase where both the crystalline and the superfluid orders coexist. In addition, we obtain signatures for solitary waves and also superfluidity.Comment: 7 pages, 11 figure

    Characterization of vitamin D supplementation and clinical outcomes in a large cohort of early Parkinson's disease.

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    BackgroundVitamin D (VitD) deficiency is common in Parkinson's disease (PD) and has been raised as a possible PD risk factor. In the past decade, VitD supplementation for potential prevention of age related conditions has become more common. In this study, we sought to characterize VitD supplementation in early PD and determine as an exploratory analysis whether baseline characteristics or disease progression differed according to reported VitD use.MethodsWe analyzed data from the National Institutes of Health Exploratory Trials in Parkinson's Disease (NET-PD) Long-term study (LS-1), a longitudinal study of 1741 participants. Subjects were divided into following supplement groups according to subject exposure (6 months prior to baseline and during the study): no VitD supplement, multivitamin (MVI), VitD ≥400 IU/day, and VitD + multivitamin (VitD+MVI). Clinical status was followed using the Unified Parkinson's Disease Rating Scale, Symbol Digit Modalities Test, total daily levodopa equivalent dose, and Parkinson's Disease Questionnaire.ResultsAbout 5% of subjects took VitD alone, 7% took VitD+MVI, 34% took MVI alone, while 54% took no supplement. Clinical outcomes at 3 years were similar across all groups.ConclusionThis study shows VitD supplementation ≥400 IU/day was not common in early PD and that its use was similar to that seen in the US population. At 3 years, there was no difference in disease progression according to vitamin D supplement use

    Impact of Climate Variations on Soybean Yield in Eastern Arkansas: 1960-2014

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    Climate is the major factor affecting crop production; therefore, various agro-meteorological indicators have been frequently used to evaluate the impact of climate on crop production. In this study, we examined the temporal variations of agrometeorological indicators (growing degree days, total precipitation, dry spells and drought indices) during 1960-2014 and their impact on soybean yields in East Arkansas. Results show an increasing trend in growing degree days (GDDs) and dry spells, though the total precipitation during the soybean growing season remained nearly unchanged during the study period. Generally, GDDs and dry spells show a strong correlation with yields. We also evaluated drought variability based on different drought indices, including the Palmer Drought Severity Index (PDSI), the Standardized Precipitation Index (SPI) and the Standardized Precipitation-Evapotranspiration Index (SPEI). The drought indices are all negatively correlated to soybean yields. Overall, the one month SPEI showed the strongest impact on yields. After regression analysis, Dry spells and Total precipitation were the only significant factors in the General Linear Model (GLM)

    Participatory evaluation of advanced potato (Solanum tuberosum) clones for water stress tolerance

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    An attempt was made to introduce potato (Solanum tuberosum L.) in hot arid water scarce zone of Western Rajasthan, India. Eight CIP-bred potato clones were evaluated along with two controls, viz. Kufri Pukhraj and Kufri Surya on farmer’s field at Jodhpur, Rajasthan under normal and moderate water stress regime during three winter crop seasons (2012-15). Pooled analysis revealed that CIP clone 397006.18 (34.0 tonnes/ha) out yielded Kufri Pukhraj (26.8 tonnes/ha) and Kufri Surya (20.2 tonnes/ha) for marketable tuber yield. This clone maintained yield under normal and deficit irrigation and attained 26.9% higher marketable yield under normal irrigations, which further improved by 31.3% under deficit water stress regime over the best control Kufri Pukhraj. This clone recorded highest tuber dry matter content (22.7%), statistically superior to both control Kufri Pukhraj (17.9%) and Kufri Surya (21.4%). Clone 397006.18 had highest mean drought tolerance index value (1.16) and least total weight loss under normal irrigation (4.9%) and water stress conditions (8.6%) up to 60 days of storage. Preference yield analysis by potato growers showed that they liked this clone most and its overall acceptability was fairly better for all organoleptic traits. Results of field study and participatory varietal selection indicated that clone 397006.18 performed better for tuber productivity under deficit water management, exhibited drought tolerance traits and achieved overall acceptance by the farmers in Western Rajasthan

    Barriers to coastal shipping development: an Indian perspective

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    Coastal shipping has been widely recognised as a sustainable and efficient alternative to road transport. However, the barriers encountered in the industry have not been systematically studied in any region. From an Indian perspective, this study aims to prioritise barriers to coastal shipping development for effective policy interventions. It identifies important barriers through a Delphi study and then quantifies their cause-and-effect relationships by the decision making-trial and evaluation laboratory analysis (DEMATEL) technique. It is interesting that the main barriers, those have most impact on coastal shipping development, are not necessarily the ones most widely recognised. The study also uncovers the hidden cause-and-effect relationships between several barriers. Four main barriers are identified: (1) Indian maritime legislation (especially cabotage rules); (2) issues in the infrastructure and procedures at port and port-centric areas; (3) underdevelopment of small ports; (4) lack of a collaborative culture among the various service providers involved in the logistics supply chain. This study finally recommends relaxing cabotage rules to stimulate the inflow of foreign capital to grow coastal shipping, improving the current port system through joint efforts of the ports, Indian customs and government, and fostering supply chain collaboration

    Ebola virus VP35 interaction with dynein LC8 regulates viral RNA synthesis

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    Ebola virus VP35 inhibits alpha/beta interferon production and functions as a viral polymerase cofactor. Previously, the 8-kDa cytoplasmic dynein light chain (LC8) was demonstrated to interact with VP35, but the functional consequences were unclear. Here we demonstrate that the interaction is direct and of high affinity and that binding stabilizes the VP35 N-terminal oligomerization domain and enhances viral RNA synthesis. Mutational analysis demonstrates that VP35 interaction is required for the functional effects of LC8

    PIK3CA mutations in advanced cancers: characteristics and outcomes.

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    PIK3CA mutations are frequently diagnosed in diverse cancers and may predict response to PI3K/AKT/mTOR inhibitors. It remains unclear whether they are associated with other characteristics. We analyzed characteristics and outcome of 90 consecutive patients with diverse advanced tumors and PIK3CA mutations and 180 wild-type PIK3CA controls matched by tumor type, gender, and age referred to the Clinical Center for Targeted Therapy. PIK3CA and MAPK mutations (KRAS, NRAS, and BRAF) were analyzed using polymerase chain reaction-based DNA sequencing. The most frequent PIK3CA mutations were E545K (31/90, 34%), E542K (16/90, 18%) in exon 9, and H1047R (20/90, 22%) in exon 20. PIK3CA mutations compared to wild-type PIK3CA were associated with simultaneous KRAS (p=0.047) and MAPK mutations (p=0.03), but only MAPK mutations were confirmed as having an independent association in multivariate analysis. Rates of lung, bone, liver and brain metastases were similar in PIK3CA-mutant and wild-type patients. Patients with PIK3CA mutations treated on trials with PI3K/AKT/mTOR inhibitors had a higher partial/complete response (PR/CR) rate than wild-type PIK3CA patients treated with their best phase I therapy (10/56, 18% vs. 12/152, 8%; p=0.045), but not a prolonged progression-free survival. Patients with H1047R PIK3CA mutations had higher PR/CR rate with PI3K/AKT/mTOR inhibitors compared to wild-type PIK3CA patients treated with their best phase I therapy (6/16, 38% vs. 12/152, 8%; p=0.003). In conclusion, PIK3CA mutations in diverse cancers were not associated with clinical characteristics, but were correlated with MAPK mutations. PIK3CA mutations, especially, H1047R, were associated with attaining a PR/CR to PI3K/AKT/mTOR pathway inhibitors

    Radiotracers for SPECT imaging: Current scenario and future prospects

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    Single photon emission computed tomography (SPECT) has been the cornerstone of nuclear medicine and today it is widely used to detect molecular changes in cardiovascular, neurological and oncological diseases. While SPECT has been available since the 1980s, advances in instrumentation hardware, software and the availability of new radiotracers that are creating a revival in SPECT imaging are reviewed in this paper. The biggest change in the last decade has been the fusion of CT with SPECT, which has improved attenuation correction and image quality. Advances in collimator design, replacement of sodium iodide crystals in the detectors with cadmium zinc telluride (CZT) detectors as well as advances in software and reconstruction algorithms have all helped to retain SPECT as a much needed and used technology. Today, a wide spectrum of radiotracers is available for use in cardiovascular, neurology and oncology applications. The development of several radiotracers for neurological disorders is briefly described in this review, including [ 123I]FP-CIT (DaTSCAN ™) available for Parkinson's disease. In cardiology, while technetium-99m labeled tetrofosmin and technetium-99m labeled sestamibi have been well known for myocardial perfusion imaging, we describe a recently completed multicenter clinical study on the use of [ 123I]mIBG (AdreView ™) for imaging in chronic heart failure patients. For oncology, while bone scanning has been prevalent, newer radiotracers that target cancer mechanisms are being developed. Technetium-99m labeled RGD peptides have been reported in the literature that can be used for imaging angiogenesis, while technetium-99m labeled duramycin has been used to image apoptosis. While PET/CT is considered to be the more advanced technology particularly for oncology applications, SPECT continues to be the modality of choice and the workhorse in many hospitals and nuclear medicine centers. The cost of SPECT instruments also makes them more attractive in developing countries where the cost of a scan is still prohibitive for many patients
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