Quality vs. Quantity of Data in Contextual Decision-Making: Exact Analysis under Newsvendor Loss

When building datasets, one needs to invest time, money and energy to either aggregate more data or to improve their quality. The most common practice favors quantity over quality without necessarily quantifying the trade-off that emerges. In this work, we study data-driven contextual decision-making and the performance implications of quality and quantity of data. We focus on contextual decision-making with a Newsvendor loss. This loss is that of a central capacity planning problem in Operations Research, but also that associated with quantile regression. We consider a model in which outcomes observed in similar contexts have similar distributions and analyze the performance of a classical class of kernel policies which weigh data according to their similarity in a contextual space. We develop a series of results that lead to an exact characterization of the worst-case expected regret of these policies. This exact characterization applies to any sample size and any observed contexts. The model we develop is flexible, and captures the case of partially observed contexts. This exact analysis enables to unveil new structural insights on the learning behavior of uniform kernel methods: i) the specialized analysis leads to very large improvements in quantification of performance compared to state of the art general purpose bounds. ii) we show an important non-monotonicity of the performance as a function of data size not captured by previous bounds; and iii) we show that in some regimes, a little increase in the quality of the data can dramatically reduce the amount of samples required to reach a performance target. All in all, our work demonstrates that it is possible to quantify in a precise fashion the interplay of data quality and quantity, and performance in a central problem class. It also highlights the need for problem specific bounds in order to understand the trade-offs at play

Mitochondrial Genome Maintenance: Damage and Repair Pathways

The mitochondrial genomic material (mtDNA), similarly to nuclear genome, is exposed to a plethora of exogenous and endogenous agents, as well as natural processes like replication that compromise the integrity and fidelity of the mtDNA, despite the abovementioned, the mtDNA does not contain genes involved in DNA repair, therefore mitochondria completely depend on the importation of nuclear-encoded elements to achieve genome maintenance, which implies a coordinated crosstalk between these two organelles. It has been determined that to counteract damage, mitochondria possess well-defined repair pathways quite similar to those of the nucleus, among which are: base excision repair (BER), mismatch repair (MMR), single-strand break repair (SSBR), microhomology-mediated end joining (MMEJ), and probably homology recombination dependent repair (HRR). If these repair pathways are nonfunctional and the lesions remain unrepaired, the emergence of mutations, deletions, and other insults may result in compromised cellular viability and disease

Strengthening District Health Management In Low-Middle Income Countries: Reflections And Way Forward

Health systems in low-middle income countries are undergoing considerable changes in a context of ongoing health sector reforms. Districts have, therefore, been increasingly recognised as the level where health policies and health sector reforms are interpreted and implemented. At the same time, decentralisation in its different forms has become a popular reform in many countries, and this increases the importance of ensuring that districts have the organisational capacity to offer a good service. Aim: The article investigates the process, challenges and opportunities of health system development at district level in low-middle income countries. Discussion: While district strengthening is probably necessary in relation to the success of all other health reforms, it is argued that it has not been accorded the importance probably because it is not seen as glamorous. The district health management team must include both strengthening the capacity of individuals, but crucially also, improvement of systems. Many initiatives have been patchy and fail to provide a consistent national approach. The persistence of top-down approaches to health care works directly against districts being able to take charge of their own affairs. Conclusions: A shared vision of district strengthening must be achieved in order to progress with the achievement of Universal Health Coverage and Sustainable Development Goals

Microalbuminuria and glycated hemoglobin in children with type 1 diabetes mellitus

Diabetic nephropathy (DNP) is a microvascular complication that occurs in 20–40% of patients with type 1 diabetes (T1D). The main modifiable DNP initiation and progression factors in susceptible individuals may be sustained hyperglycemia and hypertension. The aim of the present work was to study glycemic control in children with T1D and the risk of microalbuminuria (MA) expressed as the urinary albumin/creatinine ratio (ACR).Subjects and methods: Forty children with T1D attending the diabetes clinic at the Alexandria University Children’s Hospital with a duration of diabetes of 3 years or more were included in the study and twenty apparently normal children were taken as controls. Clinical examination and blood pressure measurements were performed for all cases. Urine samples were collected within a 3–6 month period. The ACR in 2 of 3 specimens should be >30 mg/g before considering a patient to have microalbuminuria. HbA1c was measured and the mean of the last 4 readings was calculated.Results: 77.5% of patients had ACR >30 mg/g in two different samples. 88.8% of patients with poor glycemic control had MA compared to 53.8% with accepted glycemic control. The difference was more statistically significant among the adolescent age group (P = 0.001). MA was found in 77.2% of children with duration of T1D less than 5 years but the highest proportion was found when the disease duration was more than 10 years. There was no significant difference in systolic and diastolic blood pressure among diabetic children with and without MA (P = 0.556 and 0.781).Conclusion: Microalbuminuria in children with T1 DM is not limited to those with diseaseduration of 5 years or more and it may occur earlier. MA is significantly associated with poor glycemic control especially in adolescents. Other factors that may contribute to MA are not yet fully understood, further research is needed to clarify these factors

Separation and recovery of organic acids from fermented kitchen waste by an integrated process

Organic acids produced from anaerobic digestion of kitchen waste were recovered using a new integrated method which consisted of freezing and thawing, centrifugation, filtration and evaporation. The main organic acid produced was lactic acid (98%). After the freezing and thawing process, 73% of the total suspended solids were removed and the organic acids were elevated from 59.0 to 70 g/L. The evaporation technique was used to further concentrate the organic acids up to 224 g/L. Using the integrated recovery method, the reduction of the total suspended solids in the solution achieved was about 93%. The material balance for the recovery process was also presented

Supercritical carbondioxide extraction of cypermethrin in different fresh vegetables using anhydrous sodium sulfate for sample preparation and extraction

Supercritical fluid extraction (SFE) is a promising method of extraction for pesticide residues in fruits and vegetables. A rapid and high percetage of recoveries extraction of cypermethrin insecticides from fresh yardlong bean, carrot and eggplant vegetables matrixs using drying agent and SC-CO2 was developed in this study. In vegetable samples, which typically contain 80 - 95% water, but samples dry with Na2SO4 showed 96 - 105% recoveries in SFE. Moreover, the performance of drying agents (Na2SO4)and their combination such as Na2SO4 –H2O (6.7 + 1), Na2SO4 – H2O (2 + 1) and Na2SO4 – H2O (1 + 1) were evaluated. Na2SO4-H2O (1 + 1) was shown moisture conveyanced by SFE/mg highest (93) performance. Cypermethrin recovered from yardlong bean and carrot with critical pressure, PC at 20 Ibs and critical temperature, TC 40°C. On the other hand, the recovery rate of similar insecticides from egg plant was 96% with PC at 31.5 Ibs and 45°C in TC. The recovery rate in yardlong bean matrices was 100%; 105% was in carrot matrix. The retention time (tR) was 49.6 min of cypermethrin standard and similar tR was found in formulated. The lowest detectable limit (LDL) of cypermethrin insecticides was 0.02 ìg/mL with gas chromatography-electron capture detection (GC-ECD). GC-ECD temperature was of injection port and detector 280 and 300°C, respectively, with split less. However, the method is useful torecover non-polar insecticides from the fresh vegetable; thus, further research could be continued with co-solvents and different drying agents to recover the polar residues from different types of fresh vegetables

Ubiquitylation and SUMOylation: An Orchestrated Regulation During DNA Damage Repair

DNA double-strand breaks (DSBs) are cytotoxic DNA lesions that must be repaired as soon as possible because it can cause chromosomal aberrations and cell death. Homologous recombination (HR) and nonhomologous end joining (NHEJ) are the pathways that mainly repair these ruptures. HR process is finely regulated by synchronized posttranslational modifications including phosphorylation, ubiquitylation, and SUMOylation. The ubiquitin (Ub) modifications at damaged chromatin serve as recruitment platforms for DSB repair complexes by facilitating binding sites or regulating the interaction between proteins. Thus, SUMOylation has been associated with protein interaction, enzymatic activity, and chromatin mobility. Several DNA damage factors have been found to be ubiquitylated and SUMOylated including histones (H2AX) and proteins such as Mre11, Rad51, NBS1, and BRCA1. Regarding ubiquitylation-mediated regulation of DNA repair, RNF168 and RNF8 E3 ligases have turned out to be a key step in DNA damage repair regulation. Interestingly, there is evidence that the Ub signaling mechanism is ancestral, and this emphasizes its importance

Validation of Reference Genes for Robust qRT-PCR Gene Expression Analysis in the Rice Blast Fungus Magnaporthe oryzae

This is the final version of the article. Available from Public Library of Science via the DOI in this record.The rice blast fungus causes significant annual harvest losses. It also serves as a genetically-tractable model to study fungal ingress. Whilst pathogenicity determinants have been unmasked and changes in global gene expression described, we know little about Magnaporthe oryzae cell wall remodelling. Our interests, in wall remodelling genes expressed during infection, vegetative growth and under exogenous wall stress, demand robust choice of reference genes for quantitative Real Time-PCR (qRT-PCR) data normalisation. We describe the expression stability of nine candidate reference genes profiled by qRT-PCR with cDNAs derived during asexual germling development, from sexual stage perithecia and from vegetative mycelium grown under various exogenous stressors. Our Minimum Information for Publication of qRT-PCR Experiments (MIQE) compliant analysis reveals a set of robust reference genes used to track changes in the expression of the cell wall remodelling gene MGG_Crh2 (MGG_00592). We ranked nine candidate reference genes by their expression stability (M) and report the best gene combination needed for reliable gene expression normalisation, when assayed in three tissue groups (Infective, Vegetative, and Global) frequently used in M. oryzae expression studies. We found that MGG_Actin (MGG_03982) and the 40S 27a ribosomal subunit MGG_40s (MGG_02872) proved to be robust reference genes for the Infection group and MGG_40s and MGG_Ef1 (Elongation Factor1-α) for both Vegetative and Global groups. Using the above validated reference genes, M. oryzae MGG_Crh2 expression was found to be significantly (p<0.05) elevated three-fold during vegetative growth as compared with dormant spores and two fold higher under cell wall stress (Congo Red) compared to growth under optimal conditions. We recommend the combinatorial use of two reference genes, belonging to the cytoskeleton and ribosomal synthesis functional groups, MGG_Actin, MGG_40s, MGG_S8 (Ribosomal subunit 40S S8) or MGG_Ef1, which demonstrated low M values across heterogeneous tissues. By contrast, metabolic pathway genes MGG_Fad (FAD binding domain-containing protein) and MGG_Gapdh (Glyceraldehyde-3-phosphate dehydrogenase) performed poorly, due to their lack of expression stability across samples.We acknowledge funding from Khazanah Foundation in support of SCO, BBSRC grant BB/J008923/1 awarded to SG and we thank Eleanor Jaskowska for her assistance in tissue preparation. Neither funder played a role in study design, data collection, analysis, decision to publish or manuscript preparation