169 research outputs found

    Treeline dynamics with climate change at the central Nepal Himalaya

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    Treeline shifting in tandem with climate change has widely been reported from various parts of the world. In Nepal, several impacts of climate change on the physical environment have been observed, but study on the biological impacts is lacking. This dendrochronological study was carried out at the treeline in the high mountain slope of Kalchuman Lake (3750-4003 m a.s.l.) area of Manaslu Conservation Area in the central Nepal Himalaya to explore the impact of climate change on the treeline dynamic. Two belt transect plots (size: 20 m wide, > 250 m long) were laid which included treeline as well as tree species limit. Ecological mapping of all individuals of dominant trees Abies spectabilis and Betula utilis was done and their tree cores were collected. Stand character and age distribution revealed an occurrence of more matured B. utilis (max. age 198 years) compared to A. spectabilis (max. age 160 years). A. spectabilis contained an overwhelmingly high population (89) of younger plants (< 50 years) indicating its high recruitment rate. Population age structure along the elevation gradient revealed an upward shifting of A. spectabilis at the rate of 2.61 m year-1 since AD 1850. The upper distribution limit of B. utilis was found to be stagnant in the past few decades. An increment in plant density as well as upward shifting in the studied treeline ecotones was observed. The temporal growth of A. spectabilis was correlated negatively with the monthly mean and minimum temperature of June to September of the current and previous year. The regeneration of A. spectabilis, on the other hand, was positively correlated with August precipitation and monthly maximum temperature of the month of the current year. The growth and regeneration of A. spectabilis was more sensitive to maximum and minimum temperature rather than average temperature. The growth of the B. utilis was mainly limited by moisture stress during the pre-monsoon season. As these two species presented species-specific responses to climate change with differential pattern in regeneration condition, much wider differences are anticipated in their population status as climate continues to change throughout the century

    Intra-annual oxygen isotope variations in Central Indian teak cellulose: possibility of improved resolution for past monsoon reconstruction

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    A clear seasonal cycle has been detected in the intraannual oxygen isotope variations (&#948;18O) of cellulose from several annual growth rings of teak trees that grew in central India. This persistent cycle is marked by higher &#948;18O values at the ring boundaries and lower &#948;18O values at intermediate parts. The amplitude of this seasonal cycle varies up to 6.8&#8240;. Based on the pattern of teak growth reported in the literature and a plant physiological model that interprets the &#948;18O of plant cellulose, it seems possible to identify subsections of a ring that formed during pre-monsoon, peak-monsoon and post-monsoon. Comparison of the &#948;18O profile of a ring (year AD 1971), analysed with the highest resolution, and a model profile based on concurrent local meteorological data indicates the possibility of achieving a ~20 day resolution in monsoon reconstruction by intra-annual &#948;18O measurements

    Formulation and Evaluation of Pulsatile Drug Delivery System of Metoprolol Tartarate Using Core in Cup Tablet

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    Abstract The purpose of this work is to formu late a pulsatile drug delivery system using metoprolol tartarate as model drug. A core in cup (three component tablet) is prepared where in core tablet, an impermeable material surrounding the tablet except the top and soluble hydrophilic poly mer layer at the top is designed. The core tablet contains metoprolol tartarate, cellu lose acetate propionate is used as impermeable memb rane and sodium alginate 500 cps and sodium alginate 2000 cps used as soluble hydrophilic poly mer layer .The top cover layer is prepared using 3 2 factorial design. Quantification of water uptake, top layer expansion, in-v itro dissolution studies, radial and axial expansion, stereomicroscopic image, and short term stability studies are performed. The concentration of top layer of hydrophilic poly mer is a critical factor governing the release pattern, increase in the concentration increased lag t ime and delay the release .The T70% and T90 % values are also influenced by the polymer concentration with less polymer concentration of hydrophilic poly mer lesser T70% and T90 % values are obtained and as the concentration increased higher values are obtained. It can be concluded from the study that pulsatile drug delivery system useful in chronotherapy of hypertension can be prepared by this technique

    Disease knowledge after an educational program in patients with GERD – a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Patient education has proved beneficial in several but not all chronic disease. Inconsistent findings may rely on varying educational effects of various programs and differential effects on subgroups of patients. Patients' increase in disease knowledge may serve as a feedback to the educator on how well the education program works – but may not be associated to relevant clinical outcomes like quality of life (QoL). This study aimed to investigate the effects of a group based education program for patients with gastroesophageal reflux disease (GERD) on disease knowledge and the association between knowledge and QoL.</p> <p>Methods</p> <p>Patients with GERD were randomly allocated to education (102 patients) or control (109 patients). The education program was designed as a structured dialogue conveying information about pathophysiology, pharmacological and non-pharmacological treatment of GERD, patients' rights and use of healthcare. Outcomes were a 24 item knowledge test on GERD (score 0 – 24) 2 and 12 months after the educational program and disease specific and general QoL (Digestive symptoms and disease impact, DSIQ, and General Health Questionnaire, GHQ).</p> <p>Results</p> <p>Patients allocated to education achieved higher knowledge test scores than controls at 2 months (17.0 vs. 13.1, p < 0.001) and at 12 months (17.1 vs. 14.0, p < 0.001) follow-up. Knowledge test score was positively associated with having completed advanced school and inversely related to psychiatric illness and poor QoL as perceived by the patients at the time of inclusion. Overall, changes in knowledge test score were not associated with change in QoL.</p> <p>Conclusion</p> <p>A group based education program for patients with GERD designed as a structured dialogue increased patients' disease knowledge, which was retained after 1 year. Changes in GERD-knowledge were not associated with change in QoL.</p> <p>Trial registration</p> <p>ClinicalTrials.gov: NCT0061850</p

    The MeerKAT Absorption Line Survey (MALS) data release I: Stokes I image catalogs at 1-1.4 GHz

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    The MeerKAT Absorption Line Survey (MALS) has observed 391 telescope pointings at L-band (900 - 1670 MHz) at ÎŽâ‰Č\delta\lesssim +20deg⁥+20\deg. We present radio continuum images and a catalog of 495,325 (240,321) radio sources detected at a signal-to-noise ratio (SNR) >>5 over an area of 2289 deg2^2 (1132 deg2^2) at 1006 MHz (1381 MHz). Every MALS pointing contains a central bright radio source (S1 GHz≳0.2S_{1\,\mathrm{GHz}} \gtrsim 0.2 Jy). The median spatial resolution is 12â€Čâ€Č12^{\prime\prime} (8â€Čâ€Č8^{\prime\prime}). The median rms noise away from the pointing center is 25 ÎŒ\muJy beam−1^{-1} (22 ÎŒ\muJy beam−1^{-1}) and is within ∌\sim 15% of the achievable theoretical sensitivity. The flux density scale ratio and astrometric accuracy deduced from multiply observed sources in MALS are less than 1% (8% scatter) and 1â€Čâ€Č1^{\prime\prime}, respectively. Through comparisons with NVSS and FIRST at 1.4 GHz, we establish the catalog's accuracy in the flux density scale and astrometry to be better than 6% (15% scatter) and 0.8â€Čâ€Č0.8^{\prime\prime}, respectively. The median flux density offset is higher (9%) for an alternate beam model based on holographic measurements. The MALS radio source counts at 1.4 GHz are in agreement with literature. We estimate spectral indices (α\alpha) of a subset of 125,621 sources (SNR>>8), confirm the flattening of spectral indices with decreasing flux density and identify 140 ultra steep-spectrum (α<−1.3\alpha<-1.3) sources as prospective high-zz radio galaxies (z>2z>2). We have identified 1308 variable and 122 transient radio sources comprising primarily of AGN that demonstrate long-term (26 years) variability in their observed flux densities. The MALS catalogs and images are publicly available at https://mals.iucaa.in.Comment: 64 pages, 25 figures, accepted for publication in the ApJS (full version of the paper with complete tables is available at DR1 release notes

    First molecular-cytogenetic characterization of Fanconi anemia fragile sites in primary lymphocytes of FA-D2 patients in different stages of the disease

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    Background: Fanconi anemia (FA) is a chromosomal instability syndrome characterized by increased frequency of chromosomal breakages, chromosomal radial figures and accelerated telomere shortening. In this work we performed detailed molecular-cytogenetic characterization of breakpoints in primary lymphocytes of FA-D2 patients in different stages of the disease using fluorescent in situ hybridization. Results: We found that chromosomal breakpoints co-localize on the molecular level with common fragile sites, whereas their distribution pattern depends on the severity of the disease. Telomere quantitative fluorescent in situ hybridization revealed that telomere fusions and radial figures, especially radials which involve telomere sequences are the consequence of critically shortened telomeres that increase with the disease progression and could be considered as a predictive parameter during the course of the disease. Sex chromosomes in FA cells are also involved in radial formation indicating that specific X chromosome regions share homology with autosomes and also could serve as repair templates in resolving DNA damage. Conclusions: FA-D2 chromosomal breakpoints co-localize with common fragile sites, but their distribution pattern depends on the disease stage. Telomere fusions and radials figures which involve telomere sequences are the consequence of shortened telomeres, increase with disease progression and could be of predictive value

    Data Descriptor: A global multiproxy database for temperature reconstructions of the Common Era

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    Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The records are from trees, ice, sediment, corals, speleothems, documentary evidence, and other archives. They range in length from 50 to 2000 years, with a median of 547 years, while temporal resolution ranges from biweekly to centennial. Nearly half of the proxy time series are significantly correlated with HadCRUT4.2 surface temperature over the period 1850-2014. Global temperature composites show a remarkable degree of coherence between high-and low-resolution archives, with broadly similar patterns across archive types, terrestrial versus marine locations, and screening criteria. The database is suited to investigations of global and regional temperature variability over the Common Era, and is shared in the Linked Paleo Data (LiPD) format, including serializations in Matlab, R and Python.(TABLE)Since the pioneering work of D'Arrigo and Jacoby1-3, as well as Mann et al. 4,5, temperature reconstructions of the Common Era have become a key component of climate assessments6-9. Such reconstructions depend strongly on the composition of the underlying network of climate proxies10, and it is therefore critical for the climate community to have access to a community-vetted, quality-controlled database of temperature-sensitive records stored in a self-describing format. The Past Global Changes (PAGES) 2k consortium, a self-organized, international group of experts, recently assembled such a database, and used it to reconstruct surface temperature over continental-scale regions11 (hereafter, ` PAGES2k-2013').This data descriptor presents version 2.0.0 of the PAGES2k proxy temperature database (Data Citation 1). It augments the PAGES2k-2013 collection of terrestrial records with marine records assembled by the Ocean2k working group at centennial12 and annual13 time scales. In addition to these previously published data compilations, this version includes substantially more records, extensive new metadata, and validation. Furthermore, the selection criteria for records included in this version are applied more uniformly and transparently across regions, resulting in a more cohesive data product.This data descriptor describes the contents of the database, the criteria for inclusion, and quantifies the relation of each record with instrumental temperature. In addition, the paleotemperature time series are summarized as composites to highlight the most salient decadal-to centennial-scale behaviour of the dataset and check mutual consistency between paleoclimate archives. We provide extensive Matlab code to probe the database-processing, filtering and aggregating it in various ways to investigate temperature variability over the Common Era. The unique approach to data stewardship and code-sharing employed here is designed to enable an unprecedented scale of investigation of the temperature history of the Common Era, by the scientific community and citizen-scientists alike

    Processing and rheology in thermoplastic and thermoplastic composites

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    Polymer process design methodologies using design of experiments and simple empirical relationships between important process parameters and process performance criteria were developed. Thermoplastic pultrusion, single screw extrusion, and injection molding were studied to illustrate the application of the developed methodologies. The three processes considered represent different shear rate regimes. A model based on the power law viscosity-shear rate relationship was developed to predict the pulling force as a function of the pulling speed and temperature in pultrusion of the thermoplastic powder impregnated tows. Shear rate-temperature superposition principle was shown to be applicable for pulling force as a function of pulling speed and temperature in pultrusion of the thermoplastic powder impregnated towpregs made using the wet slurry process. The effects of the important process parameters on the process performance criteria were studied using statistical design of experiments in single screw extrusion and injection molding. In single screw extrusion, screw RPM and the three zone temperatures were the selected process parameters, while extruder output, melt temperature, and mechanical energy input were the selected performance criteria. In injection molding, injection speed, packing pressure, back pressure, and screw RPM were the selected process parameters, while tensile strength and impact strength were the selected performance criteria. Zone-3 temperature and screw RPM were observed to be the most important process parameters influencing the extruder output, melt temperature, and energy input in single screw extrusion. Packing pressure and injection speed were the most significant parameters affecting the tensile properties, while no process parameters affected the impact properties. Microstructural studies on the fracture surfaces of the long fiber injection molded tensile and impact specimen revealed that the number and location of the long fiber bundles with well coated individual fibers were the primary microstructural features affecting the tensile and impact behavior

    Quality of life measurement in gastrointestinal and liver disorders

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    Modern medicine has had a considerable impact on mortality rates for serious illness. Many chronic diseases which have previously been associated with an increased mortality now have survival rates approaching those of the background population. However, chronic diseases such as cancer, chronic pain syndromes, and chronic inflammatory conditions impose a considerable burden on families, the health care system, and society. Health related quality of life (HRQOL) is a concept that has developed from the need to estimate the impact of such chronic diseases. HRQOL measurement is a conceptual framework which attempts to predict daily function and well being based on subjective attitudes and experiences of physical, social, and emotional health. It has been evaluated predominantly from the patient's viewpoint as proxy respondents appear to underestimate the full effect of chronic illness on functional status. Measuring HRQOL in clinical research is most frequently undertaken using multi-item questionnaires to estimate daily function. Factors which affect HRQOL can be broadly classed as disease related and disease independent. The use of different assessment techniques permits comparisons between and within disorders. Generic and disease specific instruments used together enhance the ability to direct treatment for individuals and patient populations. Psychometrically sound questionnaires must be used. However, the type of instrument and research methods adopted depend on the question of interest. We have attempted to catalogue and critically assess the disease specific instruments used in the assessment of chronic gastrointestinal disease.‹
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