1,610 research outputs found
Rotational analysis of the 7000 Å (A 3Φ→X 3Δ) electronic emission system of diatomic vanadium mononitride (VN)
The (0,0) band of the electronic emission system of the diatomic molecule VN at ∼7000 Å has been generated and rotationally analyzed. The system is 3 Φr →3 Δr and is the vanadium analog of the niobium nitride system centered ∼6029 Å. The constants for the upper and lower (almost certainly the ground) states have been determined, including estimates of the spin–orbit coupling constants, despite the absence of satellite bands. The subband origins are somewhat asymmetrically located, probably due to the interaction of the 3 Δ2 and the higher lying (by ∼3000 cm−1 ) 1 Δ2 state. There is no evidence of localized perturbations in any of the subbands. VN has the shortest bond length (r0 =1.566 Å ) observed for any diatomic molecule containing a transition metal (apart from some hydrides). The (1,1) sequence bands have also been observed but have not been rotationally analyzed at this time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70667/2/JCPSA6-90-10-5333-1.pd
Changes in the gut microbiota of mice orally exposed to methylimidazolium ionic liquids
Ionic liquids are salts used in a variety of industrial processes, and being relatively non-volatile, are proposed as environmentally-friendly replacements for existing volatile liquids. Methylimidazolium ionic liquids resist complete degradation in the environment, likely because the imidazolium moiety does not exist naturally in biological systems. However, there is limited data available regarding their mammalian effects in vivo. This study aimed to examine the effects of exposing mice separately to 2 different methylimidazolium ionic liquids (BMI and M8OI) through their addition to drinking water. Potential effects on key target organs-the liver and kidney-were examined, as well as the gut microbiome. Adult male mice were exposed to drinking water containing ionic liquids at a concentration of 440 mg/L for 18 weeks prior to examination of tissues, serum, urine and the gut microbiome. Histopathology was performed on tissues and clinical chemistry on serum for biomarkers of hepatic and renal injury. Bacterial DNA was isolated from the gut contents and subjected to targeted 16S rRNA sequencing. Mild hepatic and renal effects were limited to glycogen depletion and mild degenerative changes respectively. No hepatic or renal adverse effects were observed. In contrast, ionic liquid exposure altered gut microbial composition but not overall alpha diversity. Proportional abundance of Lachnospiraceae, Clostridia and Coriobacteriaceae spp. were significantly greater in ionic liquid-exposed mice, as were predicted KEGG functional pathways associated with xenobiotic and amino acid metabolism. Exposure to ionic liquids via drinking water therefore resulted in marked changes in the gut microbiome in mice prior to any overt pathological effects in target organs. Ionic liquids may be an emerging risk to health through their potential effects on the gut microbiome, which is implicated in the causes and/or severity of an array of chronic disease in humans
Rasch analysis of the 23-item version of the Roland Morris Disability Questionnaire
Objective: To determine the psychometric properties of the 23-item version of the Roland Morris Disability Questionnaire (RMDQ-23) and to quantify their stability across 2 cultures/languages and 2 types of care-settings. Methods: Rasch analysis of data from 1,000 patients with low back pain from primary care (UK and Denmark) and secondary care (Denmark). Results: The RMDQ-23 is unidimensional if local item dependency issues are accommodated, but contains several misfitting or overdiscriminating items, some poor targeting of items, and the scoring of 4-5 items is differentially affected by common clinical characteristics (such as age, gender, pain intensity, pain duration and care setting), depending on the country. Conclusion: As similar results have been found for the RMDQ-24, we believe it is timely to reconsider whether: (i) the RMDQ should be reconstructed using an item-response theory-based approach that includes consideration of new items and response options; or (ii) the use of alternative questionnaires should be recommended, such as the Oswestry Disability Index, that have shown evidence of fitting the Rasch model; or (iii) a completely new condition-specific questionnaire should be developed, perhaps utilizing a computerized adaptive testing platform
An interpretation of documentary and oral primary source materials for the period September 1945 until May 1946 in the region of Cochinchina and Southern Annam.
The aim of this study is to place in historical perspective the Allied (mainly British) occupation of key areas in southern French Indochina in 1945-1946. This occupation was of profound importance in the subsequent course of history in Vietnam. Although this work is concerned primarily with events in Indochina in and I946, earlier material is introduced in order to place these events in historical context. The relevant research spanned three continents, and was conducted in Saigon, Prance, Great Britain and the United States. Sources include newly-released archival material in the Public Record Office, London, and official and unofficial published material in the British Library, Imperial War Museum and the French Army's Historical Service in Paris. Personal interviews were also conducted with key contemporary British, French and Vietnamese military and civil officials. Of vital importance were the personal papers of the British Force Commander in Saigon, the late General Sir Douglas Gracey. These papers have never previously been examined, and they shed a great deal of light on events in Saigon in 1945-1946; they also refute much of what has been written on this period by various historians. It will be seen that divergent Allied policy, especially the narrow US "anticolonial" views which compelled America actively to support the Communists in Vietnam, were of fundamental importance to the formation and ultimate victory of the Democratic Republic of Vietnam. It should also be apparent that the British Commander in Vietnam, General Gracey, who has consistently been inaccurately portrayed as a politically ignorant throwback to a simpler colonial past, was in fact a shrewd and farsighted officer of considerable ability who was fully attuned to the shifting tide of historical forces. It would not seem unreasonable to suggest that, in some measure, Douglas Gracey was directly responsible for South Vietnam enjoying three decades of freedom from Communist rule. This thesis is perforce based on predominantly British source material. This is because the occupation was primarily a British operation, and not to have observed this constraint would have resulted in a study of encyclopedic proportions
HadISD: a quality-controlled global synoptic report database for selected variables at long-term stations from 1973--2011
[Abridged] This paper describes the creation of HadISD: an automatically
quality-controlled synoptic resolution dataset of temperature, dewpoint
temperature, sea-level pressure, wind speed, wind direction and cloud cover
from global weather stations for 1973--2011. The full dataset consists of over
6000 stations, with 3427 long-term stations deemed to have sufficient sampling
and quality for climate applications requiring sub-daily resolution. As with
other surface datasets, coverage is heavily skewed towards Northern Hemisphere
mid-latitudes.
The dataset is constructed from a large pre-existing ASCII flatfile data bank
that represents over a decade of substantial effort at data retrieval,
reformatting and provision. These raw data have had varying levels of quality
control applied to them by individual data providers. The work proceeded in
several steps: merging stations with multiple reporting identifiers;
reformatting to netCDF; quality control; and then filtering to form a final
dataset. Particular attention has been paid to maintaining true extreme values
where possible within an automated, objective process. Detailed validation has
been performed on a subset of global stations and also on UK data using known
extreme events to help finalise the QC tests. Further validation was performed
on a selection of extreme events world-wide (Hurricane Katrina in 2005, the
cold snap in Alaska in 1989 and heat waves in SE Australia in 2009). Although
the filtering has removed the poorest station records, no attempt has been made
to homogenise the data thus far. Hence non-climatic, time-varying errors may
still exist in many of the individual station records and care is needed in
inferring long-term trends from these data.
A version-control system has been constructed for this dataset to allow for
the clear documentation of any updates and corrections in the future.Comment: Published in Climate of the Past, www.clim-past.net/8/1649/2012/. 31
pages, 23 figures, 9 pages. For data see
http://www.metoffice.gov.uk/hadobs/hadis
Directed differentiation of pluripotent cells to neural lineages: homogeneous formation and differentiation of a neurectoderm population
During embryogenesis the central and peripheral nervous systems arise from a neural precursor population, neurectoderm, formed during gastrulation. We demonstrate the differentiation of mouse embryonic stem cells to neurectoderm in culture, in a manner which recapitulates embryogenesis, with the sequential and homogeneous formation of primitive ectoderm, neural plate and neural tube. Formation of neurectoderm occurs in the absence of extraembryonic endoderm or mesoderm and results in a stratified epithelium of cells with morphology, gene expression and differentiation potential consistent with positionally unspecified neural tube. Differentiation of this population to homogeneous populations of neural crest or glia was also achieved. Neurectoderm formation in culture allows elucidation of signals involved in neural specification and generation of implantable cell populations for therapeutic use
A Performance Evaluation of Vis/NIR Hyperspectral Imaging to Predict Curcumin Concentration in Fresh Turmeric Rhizomes
Hyperspectral image (HSI) analysis has the potential to estimate organic compounds in plants and foods. Curcumin is an important compound used to treat a range of medical conditions. Therefore, a method to rapidly determine rhizomes with high curcumin content on-farm would be of significant advantage for farmers. Curcumin content of rhizomes varies within, and between varieties but current chemical analysis methods are expensive and time consuming. This study compared curcumin in three turmeric (Curcuma longa) varieties and examined the potential for laboratory-based HSI to rapidly predict curcumin using the visible–near infrared (400–1000 nm) spectrum. Hyperspectral images (n = 152) of the fresh rhizome outer-skin and flesh were captured, using three local varieties (yellow, orange, and red). Distribution of curcuminoids and total curcumin was analysed. Partial least squares regression (PLSR) models were developed to predict total curcumin concentrations. Total curcumin and the proportion of three curcuminoids differed significantly among all varieties. Red turmeric had the highest total curcumin concentration (0.83 ± 0.21%) compared with orange (0.37 ± 0.12%) and yellow (0.02 ± 0.02%). PLSR models predicted curcumin using raw spectra of rhizome flesh and pooled data for all three varieties (R2c = 0.83, R2p = 0.55, ratio of prediction to deviation (RPD) = 1.51) and was slightly improved by using images of a single variety (orange) only (R2c = 0.85, R2p = 0.62, RPD = 1.65). However, prediction of curcumin using outer-skin of rhizomes was poor (R2c = 0.64, R2p = 0.37, RPD = 1.28). These models can discriminate between ‘low’ and ‘high’ values and so may be adapted into a two-level grading system. HSI has the potential to help identify turmeric rhizomes with high curcumin concentrations and allow for more efficient refinement into curcumin for medicinal purposes
Diet of Two Large Sympatric Teleosts, the Ling (Genypterus blacodes) and Hake (Merluccius australis)
Ling and hake are tertiary consumers, and as a result both may have an important structuring role in marine communities. The diets of 2064 ling and 913 hake from Chatham Rise, New Zealand, were determined from examination of stomach contents. Ling was a benthic generalist, and hake a demersal piscivore. The diet of ling was characterised by benthic crustaceans, mainly Munida gracilis and Metanephrops challengeri, and demersal fishes, mainly Macrourids and scavenged offal from fishing vessels. The diet of hake was characterised by teleost fishes, mainly macrourids and merlucciids. Multivariate analyses using distance-based linear models found the most important predictors of diet variability were depth, fish length, and vessel type (whether the sample was collected from a commercial or research vessel) for ling, and fish length and vessel type for hake. There was no interspecific predation between ling and hake, and resource competition was largely restricted to macrourid prey, although the dominant macrourid species predated by ling and hake were different. Cluster analysis of average diet of intraspecific groups of ling and hake confirmed the persistent diet separation. Although size is a central factor in determining ecological processes, similar sized ling and hake had distinctly different foraging ecology, and therefore could influence the ecosystem in different ways, and be unequally affected by ecosystem fluctuations
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