The effect of sample properties on the electron velocity in quantum Hall bars

We report on our theoretical investigation of the effects of the confining potential profile and sample size on the electron velocity distribution in (narrow) quantum-Hall systems. The electrostatic properties of the electron system are obtained by the Thomas-Fermi-Poisson nonlinear screening theory. The electron velocity distribution as a function of the lateral coordinate is obtained from the slope of the screened potential at the Fermi level and within the incompressible strips (ISs). We compare our findings with the recent experiments.Comment: 8 pages, 6 figure

Sustainable development of smallholder crop-livestock farming in developing countries

Meeting the growing demand for animal-sourced food, prompted by population growth and increases in average per-capita income in low-income countries, is a major challenge. Yet, it also presents significant potential for agricultural growth, economic development, and reduction of poverty in rural areas. The main constraints to livestock producers taking advantage of growing markets include; lack of forage and feed gaps, communal land tenure, limited access to land and water resources, weak institutions, poor infrastructure and environmental degradation. To improve rural livelihood and food security in smallholder crop-livestock farming systems, concurrent work is required to address issues regarding efficiency of production, risk within systems and development of whole value chain systems. This paper provides a review of several forage basedstudies in tropical and non-tropical dry areas of the developing countries. A central tenet of this paper is that forages have an essential role in agricultural productivity, environmental sustainability and livestock nutrition in smallholder mixed farming systems

Assessing the agronomic value of hog manure-derived struvite as a phosphorus source for spring wheat

Non-Peer ReviewedRecovery of phosphorus (P) from liquid hog manure is one option for minimizing P loss from hog operations to surface water bodies, where it can cause eutrophication. The P, recovered as magnesium ammonium phosphate hexahydrate (MgNH4PO4∙6H2O), commonly known as struvite, has slow-release properties, which could improve P use efficiency in cropping systems. This greenhouse bioassay evaluated the effectiveness of struvite as a P source for spring wheat. Struvite, monoammonium phosphate (MAP), and polymer-coated monoammonium phosphate (CMAP) were applied at rates of 25 and 50 kg P2O5 ha-1 either in the seed-row or in a side-band in the first of three crop cycles. Results for Cycle 1 indicated no significant P source, rate, application method, and soil main effects on aboveground wheat dry matter yield (DMY). Phosphorus uptake (PU) in Cycle 1, averaged across soils, rates, and applications methods, was significantly greater with MAP (5.1 mg kg-1) and CMAP (4.9 mg kg-1) than with struvite (4.1 mg kg-1) application. Similarly, P uptake efficiency (PUE) was greater for MAP (21%) and CMAP (18%) than for struvite (12%). For the second and third crop cycles in which wheat followed canola, DMY, PU, and PUE were similar for the P sources, regardless of rate, placement, or soil. These results suggest that while struvite was as good as the commercial P fertilizers with respect to DMY and, in Cycles 2 and 3, PU and PUE, it did not exhibit the beneficial residual effects that typically characterize slow release fertilizers. Nonetheless, it is encouraging to note that the unrefined struvite, which is a by-product of manure management for environmental goals, can perform as well as commercial fertilizers that are optimized for agronomic performance

Alterations of T cell activation signalling and cytokine production by postmenopausal estrogen levels

<p>Abstract</p> <p>Background</p> <p>Immunosenescence is an age-associated disorder occurring primarily in T cell compartments, including altered subset composition, functions, and activation. In women, evidence implicates diminished estrogen in the postmenopausal period as a contributing factor to diminished T cell responsiveness. Since hypoestrogenism is present in postmenopausal women, our objective focused on whether T cell activation, defined as signalling molecule expressions and activation, and function, identified as IL-2 production, were affected by low estrogen.</p> <p>Methods</p> <p>Using Jurkat 6.1 T cells, consequences of 4 pg/ml (corresponding to postmenopausal levels) or 40 pg/ml (premenopausal levels) of estradiol (E₂) were analyzed on signalling proteins, CD3-zeta, JAK2, and JAK3, determined by Western immunoblotting. These consequences were correlated with corresponding gene expressions, quantified by real time-polymerase chain reaction. Tyrosine phosphorylation of CD3-zeta was defined by immunoprecipitation and western immunoblotting following activation by T cell receptor (TcR) cross-linking. CD3-zeta expression and modulation was also confirmed in T cells from pre- and postmenopausal women. To assess functional consequences, IL-2 production, induced by PMA and ionomycin, was determined using enzyme-linked immunosorbent spot assay (ELISpot).</p> <p>Results</p> <p>At 40 pg/ml E₂, the level of signalling protein CD3-zeta was elevated 1.57-fold, compared with cells exposed to 4 pg/ml E₂. The CD3-zeta proteins also exhibited altered levels of activation-induced phosphorylation in the presence of 40 pg/ml E₂versus 4 pg/ml: 23 kD phosphorylated form increased 2.64-fold and the 21 kD form was elevated 2.95-fold. Examination of kinases associated with activation signalling also demonstrated that, in the presence of 40 pg/ml E₂, JAK2 protein expression was increased 1.64-fold (p < 0.001) and JAK3 enhanced 1.79-fold (p < 0.001) compared to 4 pg/ml. mRNA levels for CD3-zeta, JAK2, and JAK3 were significantly increased following exposure to 40 pg/ml E₂(2.39, 2.01, and 2.21 fold, respectively) versus 4 pg/ml. These findings were confirmed in vivo, since T cells from postmenopausal women exhibited 7.2-fold diminished CD3-zeta expression, compared to pre-menopausal controls and this expression was elevated 3.8-fold by addition of 40 pg/ml E₂. Functionally, Jurkat cells exposed to 40 pg/ml E₂and activated exhibited significantly elevated numbers of IL-2 producing colonies compared to 4 pg/ml (75.3 ± 2.2 versus 55.7 ± 2.1 colonies, p < 0.0001).</p> <p>Conclusion</p> <p>Jurkat T cells exposed to 4 pg/ml E₂expressed significantly diminished activation signalling proteins, correlating with reduced IL-2 production. Lower signalling protein levels appear to result from decreased CD3-zeta, JAK2, and JAK3 gene expressions. These findings may provide a molecular basis for immunosenescence associated with the postmenopausal state.</p

The effect of long-term feeding of conjugated linoleic acid on fertility in Japanese quail

The objective of this study was to determine the effects of the long-term feeding of conjugated linoleic acid (CLA) on laying hen performance, egg fertility and hatchability of fertile eggs of Japanese quail (Coturnix coturnix japonica). One hundred and sixty 7-day old Japanese quail chicks were randomly assigned to four groups (40 birds per group) and fed for five weeks on a commercial diet supplemented with either 0.5% hazelnut (Group A), 0.5% sunflower oil (Group B), 0.25% CLA (Group C) or 0.5% CLA (Group D). The birds received water and feed ad libitum during the study. At the end of the five weeks the birds were sexed, and 21 females and seven males from each group were selected. For a further six weeks these selected birds were fed a layer diet supplemented with their respective sources of oil. Eggs were collected daily and incubated weekly. The fertility rate was determined by visual inspection at the end of the incubation period. Dietary CLA at the inclusion level of 0.5%, but not at 0.25%, caused a significant decrease in percentage hatchability of the fertile eggs compared to Groups A and B. Hatchability of fertile eggs from Groups A, B, C and D was 74, 80, 72 and 70, respectively. Fertility rates between Groups A, B, C and D did not differ significantly, and were 64.4, 56.4, 66.0 and 62.8%, respectively. Hen-day egg production of Groups A, C and D were similar, but in weeks 3, 4, 5 and 6, hens in Group B had a significantly lower hen-day egg production (%) compared to Group A. Also, in weeks 3, 4, 5 and 6, egg size in Group B was significantly lower than that in the other groups. From this study it is concluded that dietary CLA at inclusion levels of 0.25% or 0.5% did not influence egg fertility, egg weight and egg production in Japanese quail. South African Journal of Animal Science Vol. 36(2) 2006: 99-10

The effects of community interventions on unplanned healthcare use in patients with multimorbidity: a systematic review

OBJECTIVES: To summarise the impact of community-based interventions for multimorbid patients on unplanned healthcare use. The prevalence of multimorbidity (co-existence of multiple chronic conditions) is rapidly increasing and affects one-third of the global population. Patients with multimorbidity have complex healthcare needs and greater unplanned healthcare usage. Community-based interventions allow for continued care of patients outside hospitals, but few studies have explored the effects of these interventions on unplanned healthcare usage. DESIGN: A systematic review was conducted. MEDLINE, EMBASE, PsychINFO and Cochrane Library online databases were searched. Studies were screened and underwent risk of bias assessment. Data were synthesised using narrative synthesis. SETTING: Community-based interventions. PARTICIPANTS: Patients with multimorbidity. MAIN OUTCOME MEASURES: Unplanned healthcare usage. RESULTS: Thirteen studies, including a total of 6148 participants, were included. All included studies came from high-income settings and had elderly populations. All studies measured emergency department attendances as their primary outcome. Risk of bias was generally low. Most community interventions were multifaceted with emphasis on education, self-monitoring of symptoms and regular follow-ups. Four studies looked at improved care coordination, advance care planning and palliative care. All 13 studies found a decrease in emergency department visits post-intervention with risk reduction ranging from 0 (95% confidencec interval [CI]: -0.37 to 0.37) to 0.735 (95% CI: 0.688-0.785). CONCLUSIONS: Community-based interventions have potential to reduce emergency department visits in patients with multimorbidity. Identification of specific successful components of interventions was challenging given the overlaps between interventions. Policymakers should recognise the importance of community interventions and aim to integrate aspects of these into existing healthcare structures. Future research should investigate the impact of such interventions with broader participant characteristics

Realistic modelling of quantum point contacts subject to high magnetic fields and with current bias at out of linear response regime

The electron and current density distributions in the close proximity of quantum point contacts (QPCs) are investigated. A three dimensional Poisson equation is solved self-consistently to obtain the electron density and potential profile in the absence of an external magnetic field for gate and etching defined devices. We observe the surface charges and their apparent effect on the confinement potential, when considering the (deeply) etched QPCs. In the presence of an external magnetic field, we investigate the formation of the incompressible strips and their influence on the current distribution both in the linear response and out of linear response regime. A spatial asymmetry of the current carrying incompressible strips, induced by the large source drain voltages, is reported for such devices in the non-linear regime.Comment: 16 Pages, 9 Figures, submitted to PR

Structural tuning of color chromaticity through nonradiative energy transfer by interspacing CdTe nanocrystal monolayers

Cataloged from PDF version of article.We proposed and demonstrated architectural tuning of color chromaticity by controlling photoluminescence decay kinetics through nonradiative Forster resonance energy transfer in the heterostructure of layer-by-layer spaced CdTe nanocrystal (NC) solids. We achieved highly sensitive tuning by precisely adjusting the energy transfer efficiency from donor NCs to acceptor NCs via controlling interspacing between them at the nanoscale. By modifying decay lifetimes of donors from 12.05 to 2.96 ns and acceptors from 3.68 to 14.57 ns, we fine-tuned chromaticity coordinates from (x,y)=(0.575,0.424) to (0.632, 0.367). This structural adjustment enabled a postsynthesis color tuning capability, alternative or additive to using the size, shape, and composition of NCs

Depression and unplanned secondary healthcare use in patients with multimorbidity: a systematic review

Background: Growing numbers of people with multimorbidity have a co-occurring mental health condition such as depression. Co-occurring depression is associated with poor patient outcomes and increased healthcare costs including unplanned use of secondary healthcare which may be avoidable. Aim: To summarise the current evidence on the association between depression and unplanned secondary healthcare use among patients with multimorbidity. Methods: We conducted a systematic review by searching MEDLINE, EMBASE, PsychINFO, Web of Science, CINAHL, and Cochrane Library from January 2000 to March 2021. We included studies on adults with depression and at least one other physical long-term condition that examined risk of emergency hospital admissions as a primary outcome, alongside emergency department visits or emergency readmissions. Studies were assessed for risk of bias using The National Institute of Health National Heart, Lung, and Blood Institute quality assessment tool. Relevant data were extracted from studies and a narrative synthesis of findings produced. Results: Twenty observational studies were included in the review. Depression was significantly associated with different outcomes of unplanned secondary healthcare use, across various comorbidities. Among the studies examining these outcomes, depression predicted emergency department visits in 7 out of 9 studies; emergency hospital admissions in 19 out of 20 studies; and emergency readmissions in 4 out of 4 studies. This effect increased with greater severity of depression. Other predictors of unplanned secondary care reported include increased age, being female, and presence of greater numbers of comorbidities. Conclusion: Depression predicted increased risk of unplanned secondary healthcare use in individuals with multimorbidity. The literature indicates a research gap in identifying and understanding the impact of complex multimorbidity combinations, and other patient characteristics on unplanned care in patients with depression. Findings indicate the need to improve planned care for patients with moderate-to-severe depression. We suggest regular reviews of care plans, depression severity monitoring and assessment of hospital admission risk in primary care settings