HIGH-ORDER FINITE DIFFERENCE METHOD APPLIED TO THE SOLUTION OF THE THREE-DIMENSIONAL HEAT TRANSFER EQUATION AND TO THE STUDY OF HEAT EXCHANGERS

Numerical experiments for four test problems are carried out to demonstrate the performance of the present method and to compare it with the others classical methods. The numerical solutions obtained are compared with the analytical solution as well as the results by other numerical schemes with emphasis on the application involving heat exchange in a rectangular channel. It can be easily seen that the proposed method is simple to implement and very efficient

Breastfeeding discontinuation not associated with maternal pregravid BMI but associated with Native Hawaiian or Other Pacific Islander race in Hawaii and Puerto Rico WIC participants

Objectives This study investigated the association between maternal pregravid body mass index (BMI) and breastfeeding discontinuation at 4-6 months postpartum in Hawaii and Puerto Rico participants from the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Methods A secondary data analysis was conducted from a text message-based intervention in WIC participants in Hawaii and Puerto Rico. The analysis included 87 women from the control group who initiated breastfeeding and whose breastfeeding status was known at the end of the study when infants were 4-6 months old. Pregravid BMI and breastfeeding discontinuation were assessed using questionnaires. Results The association between pregravid BMI and breastfeeding discontinuation was not significant in the unadjusted model or in the adjusted model. Native Hawaiian or Other Pacific Islander (NHOPI) participants showed significantly increased odds of discontinuing breastfeeding (adjusted odds ratio [AOR] 7.12; 95% CI 1.34, 37.97; p = .02) compared to all the other racial/ethnic participants, as did older women ages 32-39 years versus women who were 25-31 years old (AOR 4.21; 95% CI 1.13, 15.72; p = .03). Women who took vitamins while breastfeeding had decreased odds of discontinuing breastfeeding (AOR 0.15; 95% CI 0.05, 0.46; p = .0009). Conclusions for Practice Pregravid BMI was not significantly associated with breastfeeding discontinuation at 4-6 months postpartum in women from Hawaii and Puerto Rico WIC, but NHOPIs and women who were older had higher odds of discontinuing breastfeeding. The results of this study may inform strategies for breastfeeding promotion and childhood obesity prevention but should be further investigated in larger studies. ClinicalTrials.gov Identifier: NCT02903186

Rapidly-converging methods for the location of quantum critical points from finite-size data

We analyze in detail, beyond the usual scaling hypothesis, the finite-size convergence of static quantities toward the thermodynamic limit. In this way we are able to obtain sequences of pseudo-critical points which display a faster convergence rate as compared to currently used methods. The approaches are valid in any spatial dimension and for any value of the dynamic exponent. We demonstrate the effectiveness of our methods both analytically on the basis of the one dimensional XY model, and numerically considering c = 1 transitions occurring in non integrable spin models. In particular, we show that these general methods are able to locate precisely the onset of the Berezinskii-Kosterlitz-Thouless transition making only use of ground-state properties on relatively small systems.Comment: 9 pages, 2 EPS figures, RevTeX style. Updated to published versio

Cell death induced by the application of alternating magnetic fields to nanoparticle-loaded dendritic cells

In this work, the capability of primary, monocyte-derived dendritic cells (DCs) to uptake iron oxide magnetic nanoparticles (MNPs) is assessed and a strategy to induce selective cell death in these MNP-loaded DCs using external alternating magnetic fields (AMFs) is reported. No significant decrease in the cell viability of MNP-loaded DCs, compared to the control samples, was observed after five days of culture. The amount of MNPs incorporated into the cytoplasm was measured by magnetometry, which confirmed that 1 to 5 pg of the particles were uploaded per cell. The intracellular distribution of these MNPs, assessed by transmission electron microscopy, was found to be primarily inside the endosomic structures. These cells were then subjected to an AMF for 30 min, and the viability of the blank DCs (i.e., without MNPs), which were used as control samples, remained essentially unaffected. However, a remarkable decrease of viability from approximately 90% to 2-5% of DCs previously loaded with MNPs was observed after the same 30 min exposure to an AMF. The same results were obtained using MNPs having either positive (NH2+) or negative (COOH-) surface functional groups. In spite of the massive cell death induced by application of AMF to MNP-loaded DCs, the amount of incorporated magnetic particles did not raise the temperature of the cell culture. Clear morphological changes at the cell structure after magnetic field application were observed using scanning electron microscopy. Therefore, local damage produced by the MNPs could be the main mechanism for the selective cell death of MNP-loaded DCs under an AMF. Based on the ability of these cells to evade the reticuloendothelial system, these complexes combined with an AMF should be considered as a potentially powerful tool for tumour therapy.Comment: In Press. 33 pages, 11 figure

Ecologia e status de conservação do jacaré-paguá nas montanhas do Amolar, Pantanal Sul.

Paleosuchus palpebrosus é considerado entre as 22 espécies de crocodilianos a menor em tamanho, atingindo no máximo 1.6 m de comprimento (Medem, 1981). Paleosuchus significa "crocodilo antigo", derivado de palaios (antigo em grego) e soukhos que significa crocodilo, e palpebrosus significa "pálpebra espessa" referindo-se às pálpebras que possuem placas ósseas. Dentre as cinco espécies que ocorrem no Brasil, tem a sua distribuição marcante ao longo dos rios Amazonas, Paraguai e Paraná e de suas áreas inundadas, excluindo a área central do Pantanal (Magnusson, 1985). No entanto, um dos maiores problemas que afeta as populações naturais são as modificações dos seus habitats aliado ao total desconhecimento da sua distribuição e abundância ao longo da área de distribuição (Campos et al., 1995). A falta de informação da ecologia da espécie, apesar da extensa distribuição geográfica, é um fator que pode eventualmente afetar a conservação da espécie (Thorbjarnarson, 1992). Pouco é conhecido sobre reprodução e de seus habitats, mas sabe-se que as fêmeas fazem montes de folhas e gravetos e põem de 10 a 15 ovos. A dieta varia de invertebrados aquáticos, terrestres e vertebrados, principalmente peixes. Nas bordas do Pantanal, existem alguns registros de ocorrência dessa espécie no rio Paraguai, norte de Cáceres, serras da Bodoquena, Amolar e Urucum. A espécie provavelmente ocupa habitats periféricos da planície do Pantanal, causando uma separação espacial com o Caiman crocodilus yacare (jacaré-do-pantanal). Este estudo é parte de um projeto pioneiro da Embrapa-Pantanal com P. palpebrosus na região das montanhas do Amolar, que busca conhecer densidade, estrutura de tamanho, e razão sexual. Também, determinar o conteúdo estomacal dos jacarés em seu habitat natural.bitstream/item/79504/1/COT31.pd