Urinary felinine excretion in intact male cats is increased by dietary cystine

Felinine is a branched-chain sulfur amino acid present in the urine of certain Felidae, including domestic cats. The objective of the present study was to determine if additional cystine and/or dietary N would increase felinine and N-acetylfelinine excretion by intact male cats fed a low-protein (LP) diet. Feeding five adult intact male cats an LP diet (18·8% of metabolisable energy (ME) as protein) v. a high-protein diet (38·6% of ME as protein) resulted in a trend (P¼0·08) for decreased urinary felinine and no change in N-acetylfelinine excretion. In a 23 d study, when the LP diet was supplemented with L-cystine at 9·3 g/kg DM, urinary felinine:creatinine ratio showed a linear two-fold (121 %) increase (P,0·01) from 0·24 (SEM 0·05) to 0·53 (SEM 0·13) after 10 d. Subsequent feeding of the LP diet resulted in a decrease in felinine excretion to base levels. Plasma gglutamylfelinylglycine concentrations were consistent with the excretion of felinine. Supplementation of the LP diet with L-cystine (9·3 g/kg DM), dispensable amino acids and arginine to a second group (n 5) also resulted in a significant (P,0·01) but smaller (þ72 %) increase in the daily felinine:creatinine ratio (0·25 (SEM 0·04) to 0·43 (SEM 0·05)). The degree of felinine N-acetylation within groups was unaffected by dietary addition and withdrawal of amino acids. The results indicate that felinine synthesis is regulated by cystine availability, and that arginine may be physiologically important in decreasing felinine biosynthesis in intact male cats

Reflection and Ducting of Gravity Waves Inside the Sun

Internal gravity waves excited by overshoot at the bottom of the convection zone can be influenced by rotation and by the strong toroidal magnetic field that is likely to be present in the solar tachocline. Using a simple Cartesian model, we show how waves with a vertical component of propagation can be reflected when traveling through a layer containing a horizontal magnetic field with a strength that varies with depth. This interaction can prevent a portion of the downward-traveling wave energy flux from reaching the deep solar interior. If a highly reflecting magnetized layer is located some distance below the convection zone base, a duct or wave guide can be set up, wherein vertical propagation is restricted by successive reflections at the upper and lower boundaries. The presence of both upward- and downward-traveling disturbances inside the duct leads to the existence of a set of horizontally propagating modes that have significantly enhanced amplitudes. We point out that the helical structure of these waves makes them capable of generating an alpha-effect, and briefly consider the possibility that propagation in a shear of sufficient strength could lead to instability, the result of wave growth due to over-reflection.Comment: 23 pages, 5 figures. Accepted for publication in Solar Physic

Displaced but not replaced: the impact of e-learning on academic identities in higher education.

Challenges facing universities are leading many to implement institutional strategies to incorporate e-learning rather than leaving its adoption up to enthusiastic individuals. Although there is growing understanding about the impact of e-learning on the student experience, there is less understanding of academics’ perceptions of e-learning and its impact on their identities. This paper explores the changing nature of academic identities revealed through case study research into the implementation of e-learning at one UK university. By providing insight into the lived experiences of academics in a university in which technology is not only transforming access to knowledge but also influencing the balance of power between academic and student in knowledge production and use, it is suggested that academics may experience a jolt to their ‘trajectory of self’ when engaging with e-learning. The potential for e-learning to prompt loss of teacher presence and displacement as knowledge expert may appear to undermine the ontological security of their academic identity

Optimizing tuning masses for helicopter rotor blade vibration reduction including computed airloads and comparison with test data

The development and validation of an optimization procedure to systematically place tuning masses along a rotor blade span to minimize vibratory loads are described. The masses and their corresponding locations are the design variables that are manipulated to reduce the harmonics of hub shear for a four-bladed rotor system without adding a large mass penalty. The procedure incorporates a comprehensive helicopter analysis to calculate the airloads. Predicting changes in airloads due to changes in design variables is an important feature of this research. The procedure was applied to a one-sixth, Mach-scaled rotor blade model to place three masses and then again to place six masses. In both cases the added mass was able to achieve significant reductions in the hub shear. In addition, the procedure was applied to place a single mass of fixed value on a blade model to reduce the hub shear for three flight conditions. The analytical results were compared to experimental data from a wind tunnel test performed in the Langley Transonic Dynamics Tunnel. The correlation of the mass location was good and the trend of the mass location with respect to flight speed was predicted fairly well. However, it was noted that the analysis was not entirely successful at predicting the absolute magnitudes of the fixed system loads

Percolation model for structural phase transitions in Li1−x_{1-x}Hx_xIO3_3 mixed crystals

A percolation model is proposed to explain the structural phase transitions found in Li$_{1-x}$H$_x$IO$_3$ mixed crystals as a function of the concentration parameter $x$. The percolation thresholds are obtained from Monte Carlo simulations on the specific lattices occupied by lithium atoms and hydrogen bonds. The theoretical results strongly suggest that percolating lithium vacancies and hydrogen bonds are indeed responsible for the solid solution observed in the experimental range $0.22 < x < 0.36$.Comment: 4 pages, 2 figure

Developmental language disorders and risk of recidivism among young offenders

Background Although factors such as adverse family background have been widely examined, little is known about the prevalence or potential impact of developmental language disorder (DLD) on risk of recidivism in young people with history of criminal justice system contact. Methods A total of 145 young offenders participated. An adversity score was constructed based on information found in youth justice service records. Data collected included standardised measures of expressive and receptive language, nonverbal IQ and the inventory of callous–unemotional traits. Survival analysis was performed to examine differences in reoffending risk between young offenders with and without DLD. Results The cumulative incidence of reoffending within a year of the young person's court order was markedly raised in the DLD group (62%; 95% CI 52, 72) versus the non‐DLD group (25%; 95% CI 16, 39). Furthermore, in the final multivariable survival analysis the independent elevation in risk linked with DLD was not greatly attenuated with adjustment for nonverbal IQ, adversity score, age at first offence, number of previous offences and deprivation score. DLD was the most significant predictor with an adjusted hazard ratio of 2.61 (95% CI 1.80, 3.78). Conclusions Young offenders with DLD are more than twice as likely to reoffend than their unaffected offending peers. DLD is a powerful predictor of recidivism above and beyond other known risk factors

Fine Root Productivity and Dynamics on a Forested Floodplain in South Carolina

The highly dynamic, fine-root component of forested wetland ecosystems has received inadequate attention in the literature. Characterizing fine root dynamics is a challenging endeavor in any system, but the difficulties are particularly evident in forested floodplains where frequent hydrologic fluctuations directly influence fine root dynamics. Fine root (\u3c 3mm) biomass, production, and turnover were estimated for three soils exhibiting different drainage patterns within a mixed-oak community on the Coosawhatchie River floodplain, Jasper County, SC. Within a 45-cm deep vertical profile, 74% of total fine root biomass was restricted to the upper 15 cm of the soil surface. Fine root biomass decreased as the soil became less well-drained (e.g., fine root biomass in well-drained soil \u3e intermediately drained soil \u3e poorly drained soil). Fine root productivity was measured for one year using minirhizotrons and in-situ screens. Both methods suggested higher fine root production in better drained soils but showed frequent fluctuations in fine root growth and mortality, suggesting the need for frequent sampling at short intervals (e.g., monthly) to accurately assess fine root growth and turnover. Fine root production, estimated with in-situ screens, was 1.5, 1.8, and 0.9 Mg ha-1 yr-1 in the well-drained, intermediately drained, and poorly drained soils, respectively. Results from minirhizotrons indicated that fine roots in well-drained soils grew to greater depths while fine roots in poorly drained soils were restricted to surface soils. Minirhizotrons also revealed that the distribution of fine roots among morphological classes changed between well-drained and poorly drained soils

Low-mass pre--main-sequence stars in the Magellanic Clouds

[Abridged] The stellar Initial Mass Function (IMF) suggests that sub-solar stars form in very large numbers. Most attractive places for catching low-mass star formation in the act are young stellar clusters and associations, still (half-)embedded in star-forming regions. The low-mass stars in such regions are still in their pre--main-sequence (PMS) evolutionary phase. The peculiar nature of these objects and the contamination of their samples by the evolved populations of the Galactic disk impose demanding observational techniques for the detection of complete numbers of PMS stars in the Milky Way. The Magellanic Clouds, the companion galaxies to our own, demonstrate an exceptional star formation activity. The low extinction and stellar field contamination in star-forming regions of these galaxies imply a more efficient detection of low-mass PMS stars than in the Milky Way, but their distance from us make the application of special detection techniques unfeasible. Nonetheless, imaging with the Hubble Space Telescope yield the discovery of solar and sub-solar PMS stars in the Magellanic Clouds from photometry alone. Unprecedented numbers of such objects are identified as the low-mass stellar content of their star-forming regions, changing completely our picture of young stellar systems outside the Milky Way, and extending the extragalactic stellar IMF below the persisting threshold of a few solar masses. This review presents the recent developments in the investigation of PMS stars in the Magellanic Clouds, with special focus on the limitations by single-epoch photometry that can only be circumvented by the detailed study of the observable behavior of these stars in the color-magnitude diagram. The achieved characterization of the low-mass PMS stars in the Magellanic Clouds allowed thus a more comprehensive understanding of the star formation process in our neighboring galaxies.Comment: Review paper, 26 pages (in LaTeX style for Springer journals), 4 figures. Accepted for publication in Space Science Review

Diagnostic accuracy of the primary care screener for affective disorder (PC-SAD) in primary care

Background: Depression goes often unrecognised and untreated in non-psychiatric medical settings. Screening has recently gained acceptance as a first step towards improving depression recognition and management. The Primary Care Screener for Affective Disorders (PC-SAD) is a self-administered questionnaire to screen for Major Depressive Disorder (MDD) and Dysthymic Disorder (Dys) which has a sophisticated scoring algorithm that confers several advantages. This study tested its performance against a ‘gold standard’ diagnostic interview in primary care. Methods: A total of 416 adults attending 13 urban general internal medicine primary care practices completed the PC-SAD. Of 409 who returned a valid PC-SAD, all those scoring positive (N=151) and a random sample (N=106) of those scoring negative were selected for a 3-month telephone follow-up assessment including the administration of the Structured Clinical Interview for DSM-IV-TR Axis I Disorders (SCID-I) by a psychiatrist who was masked to PC-SAD results. Results: Most selected patients (N=212) took part in the follow-up assessment. After adjustment for partial verification bias the sensitivity, specificity, positive and negative predictive value for MDD were 90%, 83%, 51%, and 98%. For Dys, the corresponding figures were 78%, 79%, 8%, and 88%. Conclusions: While some study limitations suggest caution in interpreting our results, this study corroborated the diagnostic validity of the PC-SAD, although the low PPV may limit its usefulness with regard to Dys. Given its good psychometric properties and the short average administration time, the PC-SAD might be the screening instrument of choice in settings where the technology for computer automated scoring is available

Shrinking a large dataset to identify variables associated with increased risk of Plasmodium falciparum infection in Western Kenya

Large datasets are often not amenable to analysis using traditional single-step approaches. Here, our general objective was to apply imputation techniques, principal component analysis (PCA), elastic net and generalized linear models to a large dataset in a systematic approach to extract the most meaningful predictors for a health outcome. We extracted predictors for Plasmodium falciparum infection, from a large covariate dataset while facing limited numbers of observations, using data from the People, Animals, and their Zoonoses (PAZ) project to demonstrate these techniques: data collected from 415 homesteads in western Kenya, contained over 1500 variables that describe the health, environment, and social factors of the humans, livestock, and the homesteads in which they reside. The wide, sparse dataset was simplified to 42 predictors of P. falciparum malaria infection and wealth rankings were produced for all homesteads. The 42 predictors make biological sense and are supported by previous studies. This systematic data-mining approach we used would make many large datasets more manageable and informative for decision-making processes and health policy prioritization