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Systems to measure gas production to study digestion kinetics have been developed at several locations. The system developed at Cornell University and the rationale behind its evolution are described with an emphasis on whether venting after each observation is necessary and on choice of sensors. Different non-linear-models used to fit gas production data are discussed with an emphasis on the dual-pool logistic model. The third section of the paper includes a theoretical discussion on how gas data can be integrated with data on passage to predict ruminal digestibility. The final section addresses the practical applications of these gas data and ways in which they can be used in models like the Cornell net carbohydrate and protein system. Also included are evaluations of ensiled and freeze-dried samples from the same source as an indication of how gas systems can be used to evaluate the soluble fractions of forages.
To assess the feasibility, reliability and validity of reflection spectroscopy (RS) to assess skin carotenoids in a racially diverse sample.
Study 1 was a cross-sectional study of corner store customers (n 479) who completed the National Cancer Institute Fruit and Vegetable Screener as well as RS measures. Feasibility was assessed by examining the time it took to complete three RS measures, reliability was assessed by examining the variation between three RS measures, and validity was examined by correlation with self-reported fruit and vegetable consumption. In Study 2, validity was assessed in a smaller sample (n 30) by examining associations between RS measures and dietary carotenoids, fruits and vegetables as calculated from a validated FFQ and plasma carotenoids.
Eastern North Carolina, USA.
It took on average 94·0 s to complete three RS readings per person. The average variation between three readings for each participant was 6·8 %. In Study 2, in models adjusted for age, race and sex, there were statistically significant associations between RS measures and (i) FFQ-estimated carotenoid intake (P<0·0001); (ii) FFQ-estimated fruit and vegetable consumption (P<0·010); and (iii) plasma carotenoids (P<0·0001).
RS is a potentially improved method to approximate fruit and vegetable consumption among diverse participants. RS is portable and easy to use in field-based public health nutrition settings. More research is needed to investigate validity and sensitivity in diverse populations.
We apply cross-correlation to Pléiades satellite images to generate accurate, high-resolution monthly surface velocity maps of Monte Tronador glaciers between March and June 2012. Measured surface displacements cover periods as short as 19 days, with a precision of ∼0.58 m (11 m a−1). These glaciers follow a radial flow pattern, with maximum surface speeds of ∼390 m a−1 associated with steep icefalls. The lower reaches of the debris-covered tongues of Verde and Casa Pangue glaciers are almost stagnant, whereas Ventisquero Negro, another debris-covered glacier, shows acceleration at the front due to calving into a proglacial lake. Low-elevation debris-covered glacier tongues show increasing velocities at the beginning of the accumulation season, whereas higher-elevation, clean-ice tongues reduce their speed during this period. This contrasting behavior is probably in response to an increase in water input to the subglacial system from winter rainfall events at low elevations and a decrease in meltwater production at higher elevations. These sequential velocity maps can help to identify the controls on glacier surface velocity, aid in the delimitation of ice divides and could also contribute to more realistic calibration of ice-flux-mass–balance models in this glacierized area.
Observations show that glaciers around the world are in retreat and losing mass. Internationally coordinated for over a century, glacier monitoring activities provide an unprecedented dataset of glacier observations from ground, air and space. Glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass-balance data relating to the impact that glaciers exercise on global sea-level fluctuations or on regional runoff. In this study we provide an overview and analysis of the main observational datasets compiled by the World Glacier Monitoring Service (WGMS). The dataset on glacier front variations (∼42 000 since 1600) delivers clear evidence that centennial glacier retreat is a global phenomenon. Intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the Little Ice Age (or Holocene). Glaciological and geodetic observations (∼5200 since 1850) show that the rates of early 21st-century mass loss are without precedent on a global scale, at least for the time period observed and probably also for recorded history, as indicated also in reconstructions from written and illustrated documents. This strong imbalance implies that glaciers in many regions will very likely suffer further ice loss, even if climate remains stable.
Most glaciological studies in Argentina have focused on the large outlet glaciers of the Southern Patagonia Icefield (SPI); the numerous smaller neighboring glaciers have received significantly less attention. We present an inventory of 248 medium- to small-size glaciers (0.01–25 km2) adjacent to the northeast margin of the SPI, describe their change over the period 1979–2005 and assess local and regional climatic variations in an attempt to explain the observed glacier changes. Based on an ASTER mosaic from 20 February 2005 and the ASTER Global Digital Elevation Model, we identified a total glacier area of 187.2 ± 7.4 km2 between 600 and 2870 m a.s.l. Glaciers are largely debris-free and are concentrated in the western, more humid sector adjacent to the SPI. Using a 20 March 1979 US military intelligence Hexagon KH-9 satellite photograph, we measured a total areal reduction of ∼33.7 km2 (15.2%) between 1979 and 2005. Ablation season temperatures from the study area have followed a regional warming trend that could partly explain the observed glacier shrinkage. Annual precipitation estimates show a gradual decrease between 1979 and 2002 that may also have contributed to the ice mass loss.
In the 1970s, Feldman and Moore classified separably acting von Neumann algebras containing Cartan maximal abelian self-adjoint subalgebras (MASAs) using measured equivalence relations and 2-cocycles on such equivalence relations. In this paper we give a new classification in terms of extensions of inverse semigroups. Our approach is more algebraic in character and less point-based than that of Feldman and Moore. As an application, we give a restatement of the spectral theorem for bimodules in terms of subsets of inverse semigroups. We also show how our viewpoint leads naturally to a description of maximal subdiagonal algebras.
It has been postulated that aging is the consequence of an accelerated accumulation of somatic DNA mutations and that subsequent errors in the primary structure of proteins ultimately reach levels sufficient to affect organismal functions. The technical limitations of detecting somatic changes and the lack of insight about the minimum level of erroneous proteins to cause an error catastrophe hampered any firm conclusions on these theories. In this study, we sequenced the whole genome of DNA in whole blood of two pairs of monozygotic (MZ) twins, 40 and 100 years old, by two independent next-generation sequencing (NGS) platforms (Illumina and Complete Genomics). Potentially discordant single-base substitutions supported by both platforms were validated extensively by Sanger, Roche 454, and Ion Torrent sequencing. We demonstrate that the genomes of the two twin pairs are germ-line identical between co-twins, and that the genomes of the 100-year-old MZ twins are discerned by eight confirmed somatic single-base substitutions, five of which are within introns. Putative somatic variation between the 40-year-old twins was not confirmed in the validation phase. We conclude from this systematic effort that by using two independent NGS platforms, somatic single nucleotide substitutions can be detected, and that a century of life did not result in a large number of detectable somatic mutations in blood. The low number of somatic variants observed by using two NGS platforms might provide a framework for detecting disease-related somatic variants in phenotypically discordant MZ twins.
Drug discovery has classically targeted the active sites of enzymes or ligand-binding sites of receptors and ion channels. In an attempt to improve selectivity of drug candidates, modulation of protein–protein interfaces (PPIs) of multiprotein complexes that mediate conformation or colocation of components of cell-regulatory pathways has become a focus of interest. However, PPIs in multiprotein systems continue to pose significant challenges, as they are generally large, flat and poor in distinguishing features, making the design of small molecule antagonists a difficult task. Nevertheless, encouragement has come from the recognition that a few amino acids – so-called hotspots – may contribute the majority of interaction-free energy. The challenges posed by protein–protein interactions have led to a wellspring of creative approaches, including proteomimetics, stapled α-helical peptides and a plethora of antibody inspired molecular designs. Here, we review a more generic approach: fragment-based drug discovery. Fragments allow novel areas of chemical space to be explored more efficiently, but the initial hits have low affinity. This means that they will not normally disrupt PPIs, unless they are tethered, an approach that has been pioneered by Wells and co-workers. An alternative fragment-based approach is to stabilise the uncomplexed components of the multiprotein system in solution and employ conventional fragment-based screening. Here, we describe the current knowledge of the structures and properties of protein–protein interactions and the small molecules that can modulate them. We then describe the use of sensitive biophysical methods – nuclear magnetic resonance, X-ray crystallography, surface plasmon resonance, differential scanning fluorimetry or isothermal calorimetry – to screen and validate fragment binding. Fragment hits can subsequently be evolved into larger molecules with higher affinity and potency. These may provide new leads for drug candidates that target protein–protein interactions and have therapeutic value.
Vanadium dioxide exhibits a semiconductor to metallic phase transition at a temperature of about 68 °C. This can be exploited in the form of optical thin film structures which will exhibit non-linear behaviour when exposed to pulsed infra-red radiation. Since the phase transition is structural in nature, it is of interest to explore the temporal and spatial properties when irradiated with pulsed laser sources. Fast CMT detectors have been used to resolve nanosecond temporal detail on an experimental basis and the spatial charateristics have been explored using a simple adiabatic heating model. The dynamic transmission values measured for VO2 devices are complex combinations of the temporally and spatially varying characteristics of the film.
The ‘paddy paradox’, the occurrence of large populations of vectors but low amounts of malaria transmission where irrigated rice is grown, was investigated in a village in Ghana where M form Anopheles gambiae are common. Peridomestic and indoor host-seeking mosquitoes were collected in tent traps and light traps over 21 consecutive nights at the start of the rainy season in June 2009 when the population increased exponentially from less than 100 per night to over 1000. Infection rates in the overall mosquito population were 0.3% and in the estimated parous population were 1.9%. Numbers of An. gambiae in the tent trap peaked between midnight and 02:40 am. The majority of insects were taking their first blood meal, as virgins or shortly after mating. More than expected were collected in the light trap during a rainstorm at the start of the rains but overall numbers were not affected. Fewer than expected were collected after a subsequent storm. Recruitment to the adult population decreased over the following days. It is hypothesised that the ‘paddy paradox’ is due to young pre-gravid insects dispersing more widely than gravid ones, not necessarily to low survival in the mosquito.
The MBE growth and related materials characterisation of InSb/InAlSb strained-layer structures is described. Band-gap considerations and critical thickness calculations are presented and indicate that this material system should offer considerable device potential. Detailed structural studies, performed using both transmission electron microscopy and X-ray diffraction, confirm the growth of high quality multiple quantum-wells, and 2K photoluminescence has shown corresponding energy upshifted transitions.
The reactions of (Me3Si)3As with group III halides have been utilized to prepare AlAs, GaAs and InAs. The adduct (Me3Si)3AsAlCl3 has been isolated as an intermediate in the formation of AlAs from (Me3Si)3As and AICI3. The crystal structure of its toluene solvate has been determined.
Chemical vapor deposition experiments using (Me3Si)3As with either GaCl3 or Me3Ga at ambient pressure have produced films of GaAs on Si and semi-conducting GaAs substrates. The films have been characterized by X-ray diffraction and Auger electron spectroscopy, and each have small amounts of C and O impurities. No desired films were deposited from (C6F5)3GaAs(SiMe3)3 at 500°C and low pressures.
This paper presents the results of our investigation into the possibility of increasing both the radiative cross-section and the electrical activation efficiency in erbium (Er3+) doped silicon (Si). The energy levels of the isolated Er3+ have been theoretically predicted, employing the Thomas-Fermi method. The behaviour of these levels in Si was then investigated using a Kronig-Penney approach. Initial theoretical results imply that fluorine (F), in addition to Er3+ in Si, increases the radiative cross-section of Er3+ by at least an order of magnitude, and that co-doping appears to enhance the mixing of the 4f and 5d levels and causes the Er3+ energy levels to overlap with those of the host. Photoluminescence spectra of Er3+ in Si co-doped with F also indicate an interaction with the host lattice which appears to be dependent on its electrical characteristics.
Considerable interest has been generated recently in the application of Porous Silicon to the production of light emitting devices, and a number of demonstration structures have been produced. However, the poor stability of the material pose limitations on its usefulness. We report studies of the luminescence properties of a related, but stable material: silicon-rich silica. This material consists of silicon clusters embedded in a host matrix of silica, and as such is considerably more robust than porous silicon.
We have produced a number of samples of silicon-rich silica thin films by Plasma Enhanced Chemical Vapour Deposition on to doped silicon substrates. We report photoluminescence studies that investigate the nature of the radiative process, and show evidence of two separate luminescence mechanisms: defect luminescence and exciton confinement in nanoscale silicon clusters. Preliminary electroluminescence from silicon-rich silica fabricated by Plasma Enhanced Chemical Vapour Deposition will also be presented.
To explore the impact of diagnosis on people who experience psychosis. Eight participants were interviewed about the impact that diagnosis had on them.
The research found that the impact of diagnosis can involve both positive and negative elements. It can be a ‘means of access’ as well as a ‘cause of disempowerment’. It can help by ‘naming the problem’ and hinder by ‘labelling the person’. It is a ‘cause of social exclusion’ for all, but despite this service users can be successful in ‘achieving social inclusion’.
The findings have implications for how diagnosis is imparted by psychiatrists if they are to help to facilitate recovery and social inclusion.
Involvement of service users in the research process and examination of recovery from psychosis are two topics that have generated recent interest within the research community. This user-led study examines the subjective experience of recovery in people with experience of psychosis. Seven interviews were analysed using interpretative phenomenological analysis and several themes emerged from the data.
Recovery from psychosis was found to be a complex and idiosyncratic process, which often involved rebuilding life, rebuilding self and hope for a better future (each of these themes consisted of sub-themes).
The importance of continuity of care, the need for greater choice in approaches aimed at alleviating distress, access to stories of recovery and encouragement, and the importance of more individualised recovery care plans are among factors highlighted.
Amyloidosis of the upper aerodigestive tract is relatively rare. A case of localized amyloidosis involving all components of Waldeyer’s ring with added laryngeal involvement is described. This has not been previously reported. A literature review of this conditions is presented.