Emphasis on Mathematical Modeling: The Problems of Contour Values in Calculating the Deflection of a Beam

Mathematical Modeling has played a fundamental role in the process of teaching and learning mathematics at the various levels of education. The great challenge of today\u27s education is to create means to minimize the distance between the relations of mathematical theory and practical models of everyday life. This work aimed to treat the study of Ordinary Differential Equations through a very usual model of civil construction. Often, students of Mathematics Degree develop skills to understand the abstractions of the vast theory associated with the areas of mathematics, but without being able to exemplify and / or correlate with everyday models

Cross-fostering in the rat performed shortly after delivery: description of the procedure

This paper describes a cross-fostering procedure in rats performed shortly after delivery, The aim of the procedure was to create groups of offspring that were exposed to a lipophilie test chemical exclusively in utem or through lactation, inaddition to a control group. Time-bred dams were watched during delivery and their litters were exchanged before the young started to suekle. All dams accepted their role as foster-mothers. We had no previous experience in performing this kind of study. The following precautions taken have probably contributed to make a successful crossfostering: It was restricted access to the animal facilities during the gestation and lactation periods and only a limited number of persons performed the experimental procedure. The dams became used to handling during the gestation period. Dams were temporarily removed from their litter and cages about three hours after delivery and just before they started to nurse the young. The newborn pups were kept warm and cleaned during the switch of cages. Dams were returned to their home cages containing foster-pups. It was a minimum of physical disturbances during the delivery and the person who performed the cross-fostering was familiar to the animals through previous handling. Twenty-nine litters were successfully crossfostered

Nanopore sensing at ultra-low concentrations using single molecule dielectrophoretic trapping

Single-molecule techniques are being developed with the exciting prospect of revolutionizing the healthcare industry by generating vast amounts of genetic and proteomic data. One exceptionally promising route is in the use of nanopore sensors. However, a well-known complexity is that detection and capture is predominantly diffusion limited. This problem is compounded when taking into account the capture volume of a nanopore, typically 108–1010 times smaller than the sample volume. To rectify this disproportionate ratio, we demonstrate a simple, yet powerful, method based on coupling single-molecule dielectrophoretic trapping to nanopore sensing. We show that DNA can be captured from a controllable, but typically much larger, volume and concentrated at the tip of a metallic nanopore. This enables the detection of single molecules at concentrations as low as 5 fM, which is approximately a 103 reduction in the limit of detection compared with existing methods, while still maintaining efficient throughput

Peripartum hysterectomy incidence, risk factors and clinical characteristics in Ireland

Background: The incidence of peripartum hysterectomy (PH) shows fifty-fold variation worldwide (0.2–10.5/1000 deliveries) and risk factors include advancing maternal age and parity, previous caesarean section (CS) and abnormal placentation. Objectives: In this first national study of PH in Ireland, our objectives were threefold: to describe the national trend in PH incidence over 15 years since 1999; to assess risk of PH associated with morbidly adherent placenta (MAP), placenta praevia and postpartum haemorrhage (PPH) during 2005–2013; and to describe the causes, interventions and outcomes of PH cases during 2011–2013. Study design: For the 15-year time-trend analysis, PH cases and denominator data were extracted from Ireland’s Hospital In-Patient Enquiry database. Multivariate Poisson regression analysis assessed risk of PH associated with MAP, placenta praevia and PPH. In collaboration with the 20 Irish maternity units we carried out a three-year national clinical audit of severe maternity morbidity. PH was a notifiable morbidity and the audit included detailed review of MOH cases. Results: In 1999–2013 there were 298 PH cases, a rate of 0.32/1000 deliveries. During the period 2005–2013, the PH rate was 50 times higher in deliveries involving PPH, 100 times higher with placenta praevia and 1000 times higher with MAP. During the clinical audit (2011–2013) there were 65 PH cases, a rate of 0.33/1000 deliveries, increasing with advancing age and parity. The reporting of abnormal placentation, primarily the co-occurrence of placenta praevia and MAP, was linked with previous CS. Fifty-six of the 65 cases suffered MOH, most commonly associated with placenta praevia, MAP and uterine atony. Prophylactic and therapeutic uterotonic agents were appropriately used in the majority of cases. Conclusions: The incidence of PH in Ireland has been consistently low over 15 years, averaging one case every 3000 deliveries. The recognised risk factors of MAP, placenta praevia and PPH were independently associated with PH, with MAP being by far the strongest predictor. The vast majority of PH cases in our clinical audit were associated with MOH. Some deficiencies were noted in antenatal care, in certain elements of treatment and clinical governance protocols but adherence to guidelines was generally high

Anger management for adolescents in the school setting

The first purpose of this research paper will be to discuss what might be some of the origins of adolescent anger, as well as what specifically might provoke it. The discussion will center on such topics as family systems and how they react to anger displays, as well as social contexts in relation to anger. Second, this paper will include descriptions of several anger management programs which could be used in a school setting with adolescents. Specifically, it will include an overview of some of the most widely used programs, such as Rational Emotive Behavior Therapy, small group counseling, active relaxation, and computer-based instruction

Genomic analysis of dominance effects on milk production and conformation traits in Fleckvieh cattle

Background Estimates of dominance variance in dairy cattle based on pedigree data vary considerably across traits and amount to up to 50% of the total genetic variance for conformation traits and up to 43% for milk production traits. Using bovine SNP (single nucleotide polymorphism) genotypes, dominance variance can be estimated both at the marker level and at the animal level using genomic dominance effect relationship matrices. Yield deviations of high-density genotyped Fleckvieh cows were used to assess cross-validation accuracy of genomic predictions with additive and dominance models. The potential use of dominance variance in planned matings was also investigated. Results Variance components of nine milk production and conformation traits were estimated with additive and dominance models using yield deviations of 1996 Fleckvieh cows and ranged from 3.3% to 50.5% of the total genetic variance. REML and Gibbs sampling estimates showed good concordance. Although standard errors of estimates of dominance variance were rather large, estimates of dominance variance for milk, fat and protein yields, somatic cell score and milkability were significantly different from 0. Cross-validation accuracy of predicted breeding values was higher with genomic models than with the pedigree model. Inclusion of dominance effects did not increase the accuracy of the predicted breeding and total genetic values. Additive and dominance SNP effects for milk yield and protein yield were estimated with a BLUP (best linear unbiased prediction) model and used to calculate expectations of breeding values and total genetic values for putative offspring. Selection on total genetic value instead of breeding value would result in a larger expected total genetic superiority in progeny, i.e. 14.8% for milk yield and 27.8% for protein yield and reduce the expected additive genetic gain only by 4.5% for milk yield and 2.6% for protein yield. Conclusions Estimated dominance variance was substantial for most of the analyzed traits. Due to small dominance effect relationships between cows, predictions of individual dominance deviations were very inaccurate and including dominance in the model did not improve prediction accuracy in the cross-validation study. Exploitation of dominance variance in assortative matings was promising and did not appear to severely compromise additive genetic gain

Betaine homocysteine S-methyltransferase emerges as a new player of the nuclear methionine cycle

The paradigm of a cytoplasmic methionine cycle synthesizing/eliminating metabolites that are transported into/out of the nucleus as required has been challenged by detection of significant nuclear levels of several enzymes of this pathway. Here, we show betaine homocysteine S-methyltransferase (BHMT), an enzyme that exerts a dual function in maintenance of methionine levels and osmoregulation, as a new component of the nuclear branch of the cycle. In most tissues, low expression of Bhmt coincides with a preferential nuclear localization of the protein. Conversely, the liver, with very high Bhmt expression levels, presents a main cytoplasmic localization. Nuclear BHMT is an active homotetramer in normal liver, although the total enzyme activity in this fraction is markedly lower than in the cytosol. N-terminal basic residues play a role in cytoplasmic retention and the ratio of glutathione species regulates nucleocytoplasmic distribution. The oxidative stress associated with D-galactosamine (Gal) or buthionine sulfoximine (BSO) treatments induces BHMT nuclear translocation, an effect that is prevented by administration of N-acetylcysteine (NAC) and glutathione ethyl ester (EGSH), respectively. Unexpectedly, the hepatic nuclear accumulation induced by Gal associates with reduced nuclear BHMT activity and a trend towards increased protein homocysteinylation. Overall, our results support the involvement of BHMT in nuclear homocysteine remethylation, although moonlighting roles unrelated to its enzymatic activity in this compartment cannot be excluded.This work was supported by grants of the Ministerio de Economía y Competitividad (BFU2008-00666 and BFU2009-08977 to MAP; SAF2012-36519 and SAF2015-68590R to DPS) and Instituto de Salud Carlos III (RETIC RIRAAF RD12/0013/0008 and ARADYAL RD16/0006/0021 to DPS).Peer reviewe

iPS Cells for Modelling and Treatment of Retinal Diseases

For many decades, we have relied on immortalised retinal cell lines, histology of enucleated human eyes, animal models, clinical observation, genetic studies and human clinical trials to learn more about the pathogenesis of retinal diseases and explore treatment options. The recent availability of patient-specific induced pluripotent stem cells (iPSC) for deriving retinal lineages has added a powerful alternative tool for discovering new disease-causing mutations, studying genotype-phenotype relationships, performing therapeutics-toxicity screening and developing personalised cell therapy. This review article provides a clinical perspective on the current and potential benefits of iPSC for managing the most common blinding diseases of the eye: inherited retinal diseases and age-related macular degeneration

Tuneable 2D self-assembly of plasmonic nanoparticles at liquid|liquid interfaces

Understanding the structure and assembly of nanoparticles at liquid|liquid interfaces is paramount to their integration into devices for sensing, catalysis, electronics and optics. However, many difficulties arise when attempting to resolve the structure of such interfacial assemblies. In this article we use a combination of X-ray diffraction and optical reflectance to determine the structural arrangement and plasmon coupling between 12.8 nm diameter gold nanoparticles assembled at a water|1,2-dichloroethane interface. The liquid|liquid interface provides a molecularly flat and defect-correcting platform for nanoparticles to self-assemble. The amount of nanoparticles assembling at the interface can be controlled via the concentration of electrolyte within either the aqueous or organic phase. At higher electrolyte concentration more nanoparticles can settle at the liquid|liquid interface resulting in a decrease in nanoparticle spacing as observed from X-ray diffraction experiments. The plasmonic coupling between the nanoparticles as they come closer together is observed by a red-shift in the optical reflectance spectra. The optical reflectance and the X-ray diffraction data are combined to introduce a new 'plasmon ruler'. This allows extraction of structural information from simple optical spectroscopy techniques, with important implications for understanding the structure of self-assembled nanoparticle films at liquid interfaces.</p