Radiative-convective instability

Radiative-moist-convective equilibrium (RCE) is a simple paradigm for the statistical equilibrium the earth's climate would exhibit in the absence of lateral energy transport. It has generally been assumed that for a given solar forcing and long-lived greenhouse gas concentration, such a state would be unique, but recent work suggests that more than one stable equilibrium may be possible. Here we show that above a critical specified sea surface temperature, the ordinary RCE state becomes linearly unstable to large-scale overturning circulations. The instability migrates the RCE state toward one of the two stable equilibria first found by Raymond and Zeng (2000). It occurs when the clear-sky infrared opacity of the lower troposphere becomes so large, owing to high water vapor concentration, that variations of the radiative cooling of the lower troposphere are governed principally by variations in upper tropospheric water vapor. We show that the instability represents a subcritical bifurcation of the ordinary RCE state, leading to either a dry state with large-scale descent, or to a moist state with mean ascent; these states may be accessed by finite amplitude perturbations to ordinary RCE in the subcritical state, or spontaneously in the supercritical state. As first suggested by Raymond (2000) and Sobel et al. (2007), the latter corresponds to the phenomenon of self-aggregation of moist convection, taking the form of cloud clusters or tropical cyclones. We argue that the nonrobustness of self-aggregation in cloud system resolving models may be an artifact of running such models close to the critical temperature for instability.National Science Foundation (U.S.) (Grant AGS1032244)National Science Foundation (U.S.) (Grant 1136480)National Science Foundation (U.S.) (Grant 0850639)Massachusetts Institute of Technology. Joint Program on the Science & Policy of Global ChangeUnited States. National Oceanic and Atmospheric Administration (Postdoctoral Fellowship

Helminthic Infestation in Children Aged 6 to 59 Months with Diarrhea in Calabar

Background: Helminthic infections and diarrheal diseases have remained public health problem worldwide, especially in developing countries. Children below five years of age are at a higher risk. This study therefore aims to determine the prevalence, and intensity of intestinal helminths in children with and without the diarrheal disease. Materials and Methods: This was a cross‑sectional analytical study of 130 children aged 6 to 59 months, carried out in the Children Emergency Room and the Diarrhea Treatment and Training Unit of the University of Calabar Teaching Hospital (U. C. T. H), Calabar, Nigeria. Those admitted with and without diarrhoea were consecutively recruited. Data were obtained by administration of questionnaires to parents/caregivers whose children met the inclusion criteria. Clinical examinations including anthropometric parameters (weight and length/height) were carried out on all the children recruited for the study while mid‑upper arm circumference was done for children aged 12–59 months. Stool samples were collected from each child into a wide mouth universal, clean, dry, leak‑proof, container, with the help of their parents/guardians. Microscopy was carried out on the stool  samples collected within 1 h in the microbiology laboratory for the presence of ova, larva, or worm segment using direct microscopy with saline and iodine wet preparation and formol ether concentration. Ova were identified and quantified. The type of worm and intensity were recorded. Results: Out of the 130 children, 65 (50%) had diarrhea while the other 65 (50%) were without diarrhoea. The mean age of subjects with diarrhea was 16.86 ± 11.7 months and 17.60 ± 9.9 months for those without diarrhoea. There was no significant difference in sex distribution between the age groups (P = 0.86). The overall prevalence of intestinal helminthic infection in the study population was 1.5%. The prevalence of intestinal helminths in those with diarrhea and those without diarrhea was 3.1% and 0.0%, respectively, (P = 0.496). Only Ancylostoma duodenale (hookworm) was isolated in those with diarrhea and it was of light intensity. There was no significant  difference in the method of disposal and source of water, comparing subjects having diarrhea and those not having diarrhea (P > 0.05). The proportions of subjects that usually played in the sand, go on footwear outside home, and go on footwear at home, were not  significantly different comparing those having diarrhea and those not having diarrhea (P > 0.05). Conclusions: The prevalence rate of intestinal helminths in children with and without diarrhoea was low. There was general  environmental cleanliness and personal hygiene in the study population which were likely responsible for the low helminthic infection thus emphasizing the need for maintenance of good hygiene, access to good water supply and periodic intake of anti-helminthic drugs in view of the public health importance of helminthic infection and diarrhoea

Case studies of gender equality and social inclusion success stories in Zambia's agribusiness sector

This report presents case studies of success stories of value chain actors who operate in Zambia’s agribusiness sector to promote gender equality and social inclusion. Potential success stories were identified during a stakeholder workshop on gender equality and social inclusion in the agribusiness ecosystem for multidimensional mapping of opportunities and challenges held in September 2022 in Lusaka. Some of these stories were then selected from different value chains for follow-up by the research team. Interviews with the value chain actors in these stories were arranged and conducted in early 2023

Identification of groundnut (Arachis hypogaea) SSR markers suitable for multiple resistance traits QTL mapping in African germplasm

AbstractBackgroundThis study aimed to identify and select informative Simple Sequence Repeat (SSR) markers that may be linked to resistance to important groundnut diseases such as Early Leaf Spot, Groundnut Rosette Disease, rust and aflatoxin contamination. To this end, 799 markers were screened across 16 farmer preferred and other cultivated African groundnut varieties that are routinely used in groundnut improvement, some with known resistance traits.ResultsThe SSR markers amplified 817 loci and were graded on a scale of 1 to 4 according to successful amplification and ease of scoring of amplified alleles. Of these, 376 markers exhibited Polymorphic Information Content (PIC) values ranging from 0.06 to 0.86, with 1476 alleles detected at an average of 3.7 alleles per locus. The remaining 423 markers were either monomorphic or did not work well. The best performing polymorphic markers were subsequently used to construct a dissimilarity matrix that indicated the relatedness of the varieties in order to aid selection of appropriately diverse parents for groundnut improvement. The closest related varieties were MGV5 and ICGV-SM 90704 and most distant were Chalimbana and 47–10. The mean dissimilarity value was 0.51, ranging from 0.34 to 0.66.DiscussionOf the 376 informative markers identified in this study, 139 (37%) have previously been mapped to the Arachis genome and can now be employed in Quantitative Trait Loci (QTL) mapping and the additional 237 markers identified can be used to improve the efficiency of introgression of resistance to multiple important biotic constraints into farmer-preferred varieties of Sub-Saharan Africa

Performance of field-emitting resonating carbon nanotubes as radio-frequency demodulators

International audienceWe report on a systematic study of the use of resonating nanotubes in a field emission (FE) configuration to demodulate radio frequency signals. We particularly concentrate on how the demodulation depends on the variation of the field amplification factor during resonance. Analytical formulas describing the demodulation are derived as functions of the system parameters. Experiments using AM and FM demodulations in a transmission electron microscope are also presented with a determination of all the pertinent experimental parameters. Finally we discuss the use of CNTs undergoing FE as nanoantennae and the different geometries that could be used for optimization and implementation. © 2011 American Physical Society

Host proteostasis modulates influenza evolution

Predicting and constraining RNA virus evolution require understanding the molecular factors that define the mutational landscape accessible to these pathogens. RNA viruses typically have high mutation rates, resulting in frequent production of protein variants with compromised biophysical properties. Their evolution is necessarily constrained by the consequent challenge to protein folding and function. We hypothesized that host proteostasis mechanisms may be significant determinants of the fitness of viral protein variants, serving as a critical force shaping viral evolution. Here, we test that hypothesis by propagating influenza in host cells displaying chemically-controlled, divergent proteostasis environments. We find that both the nature of selection on the influenza genome and the accessibility of specific mutational trajectories are significantly impacted by host proteostasis. These findings provide new insights into features of host-pathogen interactions that shape viral evolution, and into the potential design of host proteostasis-targeted antiviral therapeutics that are refractory to resistance.National Institutes of Health (U.S.) (Award 1DP2GM119162)National Institutes of Health (U.S.) (Grant P30-ES002109

Leaning in to Address Sleep Disturbances and Sleep Disorders in Department of Defense and Defense Health Agency

Letter to the Editor, Military Medicine, 187, 5/6:155, 202217 USC 105 interim-entered record; under review.The article of record as published may be found at http://dx.doi.org/10.1177/0018720820906050In their article entitled, “Engaging Stakeholders to Optimize Sleep Disorders Management in the U.S. Military: A Qualitative Analysis,” Abdelwadoud and colleagues conducted focus groups of service members, primary care managers (PCMs), and administrative stakeholders about their perceptions, experiences, roles in sleep management, stated education needs, and management of sleep disorders.1 The qualitative methods are rigorous, and the findings reinforce and nuance prior results, especially regarding key requirements from PCMs. We feel compelled, however, to further nuance the authors’ conclusion that “current military sleep management practices are neither satisfactory nor maximally effective” and offer specific examples of actions taken by the Department of Defense (DoD) and Defense Health Agency (DHA) in recognition of the significance of optimal sleep in combat readiness and overall health of service members. We offer here a succinct list of concrete efforts to support and implement substantial clinical, operational, research, or educational efforts by the DoD or DHA to improve sleep in service members and associated clinical challenges in this unique population.Identified in text as U.S. Government work

Histopathologic spectrum of childhood tumours in a Tertiary Hospital: a ten-year review

Background: There has been a growing public health burden of childhood tumours in low and middle income countries (LMICs) as the trend in epidemiological transition continues to vary. Objective: The objective of this report is to determine the spectrum of childhood tumours at a tertiary hospital in Nigeria. Methods: A retrospective review of the histopathology register over the period January 2006 to December 2015. Results: The total paediatric tumour cases was 248, including 143 (57.7%) females and 105 (42.3%) males, aged 0 \u2013 12 years (mean 6.1years \ub1 3.97 SD). The age group 2 - 5 year cohort had the highest prevalence of tumour. The predominant tumour based on tissue of origin was epithelial neoplasms 88 (35.5%), vascular neoplasms 56 (22.6%), neural neoplasm 42 (16.9%), mesenchymal neoplasm 37 (14.9%), germ cell neoplasm 13 (5.2%) and haematopoietic neoplasms 12 (4.8%). Majority of the tumours were benign, 148 (59.7%) and malignant 100 (40.3%). The most predominant benign tumour was haemangioma 33 (13.3%) and predominant malignant tumour was lymphoma 22 (8.9%). Conclusion: Benign tumours remain the commonest neoplasm of children in this hospital-based data. Development and implementation of a tumour registry would provide a more comprehensive information

Kernel Spectral Clustering and applications

In this chapter we review the main literature related to kernel spectral clustering (KSC), an approach to clustering cast within a kernel-based optimization setting. KSC represents a least-squares support vector machine based formulation of spectral clustering described by a weighted kernel PCA objective. Just as in the classifier case, the binary clustering model is expressed by a hyperplane in a high dimensional space induced by a kernel. In addition, the multi-way clustering can be obtained by combining a set of binary decision functions via an Error Correcting Output Codes (ECOC) encoding scheme. Because of its model-based nature, the KSC method encompasses three main steps: training, validation, testing. In the validation stage model selection is performed to obtain tuning parameters, like the number of clusters present in the data. This is a major advantage compared to classical spectral clustering where the determination of the clustering parameters is unclear and relies on heuristics. Once a KSC model is trained on a small subset of the entire data, it is able to generalize well to unseen test points. Beyond the basic formulation, sparse KSC algorithms based on the Incomplete Cholesky Decomposition (ICD) and $L_0$, $L_1, L_0 + L_1$, Group Lasso regularization are reviewed. In that respect, we show how it is possible to handle large scale data. Also, two possible ways to perform hierarchical clustering and a soft clustering method are presented. Finally, real-world applications such as image segmentation, power load time-series clustering, document clustering and big data learning are considered.Comment: chapter contribution to the book "Unsupervised Learning Algorithms

Pharmacokinetics and biodistribution of zidovudine loaded in a solidified reverse micellar delivery system.

The aim of the research was to study the stability, release profile, pharmacokinetic and biodistribution properties of zidovudine (AZT)-solidified reverse micellar microparticulate. Lipid matrices formulated with Phospholipon® 90H and goat fat at ratios of 1:1, 2:1, 3:1 and 2:3 were used to prepare AZT-loaded SLM by melt dispersion followed by lyophilization. In vitro release studies of the drug were carried out using a sequential drug release method in both SGF (pH 1.2) and SIF (pH 7.2) while the in vivo drug release studies were carried out using Wistar albino rats. The result of our findings showed that the drug is compatibility with the lipid matrix with the 1:1 showing the most stable microparticle preparation which was then optimized. The formulations showed a concentration dependent increase in their concentration maximum (Cmax) with values of 116.05 µg/ml, 124.21 µg/ml, 128.95 µg/ml, 138.95 µg/ml and time to reach maximum concentration (Tmax) values of 5h, 8 h, 8 h, and 5 h for batches B1, B2, B3 and B4 containing 1 %, 2 %, 3 % and 5 % of AZT respectively. The area under curves (AUCs) of the microparticles formulated showed that the bioavailabilities of the microparticles were comparable to that of the conventional release tablet. The biodistribution studies of the microparticles in rats showed highest concentration of the drug in the liver with the least in the brain and higher biodistribution in various organs than pure AZT. The data suggested that SLM could be a promising drug delivery system to improve on the shortcomings of pharmacokinetics and bio-distribution properties of conventional AZT tablets like fluctuation in blood levels of the drug