Local mean-field study of capillary condensation in silica aerogels

We apply local mean-field (i.e. density functional) theory to a lattice model of a fluid in contact with a dilute, disordered gel network. The gel structure is described by a diffusion-limited cluster aggregation model. We focus on the influence of porosity on both the hysteretic and the equilibrium behavior of the fluid as one varies the chemical potential at low temperature. We show that the shape of the hysteresis loop changes from smooth to rectangular as the porosity increases and that this change is associated to disorder-induced out-of-equilibrium phase transitions that differ on adsorption and on desorption. Our results provide insight in the behavior of $^4$He in silica aerogels.Comment: 19 figure

The age-specific quantitative effects of metabolic risk factors on cardiovascular diseases and diabetes: A pooled analysis.

BACKGROUND: The effects of systolic blood pressure (SBP), serum total cholesterol (TC), fasting plasma glucose (FPG), and body mass index (BMI) on the risk of cardiovascular diseases (CVD) have been established in epidemiological studies, but consistent estimates of effect sizes by age and sex are not available. METHODS: We reviewed large cohort pooling projects, evaluating effects of baseline or usual exposure to metabolic risks on ischemic heart disease (IHD), hypertensive heart disease (HHD), stroke, diabetes, and, as relevant selected other CVDs, after adjusting for important confounders. We pooled all data to estimate relative risks (RRs) for each risk factor and examined effect modification by age or other factors, using random effects models. RESULTS: Across all risk factors, an average of 123 cohorts provided data on 1.4 million individuals and 52,000 CVD events. Each metabolic risk factor was robustly related to CVD. At the baseline age of 55-64 years, the RR for 10 mmHg higher SBP was largest for HHD (2.16; 95% CI 2.09-2.24), followed by effects on both stroke subtypes (1.66; 1.39-1.98 for hemorrhagic stroke and 1.63; 1.57-1.69 for ischemic stroke). In the same age group, RRs for 1 mmol/L higher TC were 1.44 (1.29-1.61) for IHD and 1.20 (1.15-1.25) for ischemic stroke. The RRs for 5 kg/m(2) higher BMI for ages 55-64 ranged from 2.32 (2.04-2.63) for diabetes, to 1.44 (1.40-1.48) for IHD. For 1 mmol/L higher FPG, RRs in this age group were 1.18 (1.08-1.29) for IHD and 1.14 (1.01-1.29) for total stroke. For all risk factors, proportional effects declined with age, were generally consistent by sex, and differed by region in only a few age groups for certain risk factor-disease pairs. CONCLUSION: Our results provide robust, comparable and precise estimates of the effects of major metabolic risk factors on CVD and diabetes by age group. &nbsp

High performance screen printable lithium-ion battery cathode ink based on C-LiFePO4

Lithium-ion battery cathodes have been fabricated by screen-printing through the development of CLiFePO4 inks. It is shown that shear thinning polymer solutions in N-methyl-2-pyrrolidone (NMP) with Newtonian viscosity above 0.4 Pa s are the best binders for formulating a cathode paste with satisfactory film forming properties. The paste shows an elasticity of the order of 500 Pa and, after shear yielding, shows an apparent viscosity of the order of 3 Pa s for shear rates corresponding to those used during screen-printing. The screen-printed cathode produced with a thickness of 26 mm shows a homogeneous distribution of the active material, conductive additive and polymer binder. The total resistance and diffusion coefficient of the cathode are 450 V and 2.5 10 16cm2 s 1, respectively. The developed cathodes show an initial discharge capacity of 48.2 mAh g 1 at 5C and a discharge value of 39.8 mAh g 1 after 50 cycles. The capacity retention of 83% represents 23% of the theoretical value (charge and/or discharge process in twenty minutes), demonstrating the good performance of the battery. Thus, the developed C-LiFePO4 based inks allow to fabricate screen-printed cathodes suitable for printed lithium-ion batteriesThis work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the PTDC/CTMENE/5387/2014 and UID/CTM/50025/2013 projects and grants SFRH/BD/98219/2013 (J.O.), SFRH/BD/90313/2012 (A.G.), and SFRH/BPD/112547/2015 (C.M.C.). The authors thank financial support from the Basque Government Industry Department under R.E. Sousa et al. / Electrochimica Acta 196 (2016) 92–100 99 the ELKARTEK Program. SLM thanks the Diputación de Bizkaia for financial support under the Bizkaia Talent program. The authors thank Solvay, Timcal and Phostech for kindly supplying the high quality materials. LH acknowledges FEDER funds through the COMPETE 2020 Programme and National Funds through FCT - Portuguese Foundation for Science and Technology under the project UID/CTM/50025/2013”

Trap and soil monolith sampled edaphic spiders (arachnida: araneae) in Araucaria angustifolia forest Aranhas (arachnida: araneae) edáficas amostradas por armadilhas e monólitos de solo em florestas com Araucaria angustifolia

Forests with Araucaria angustifolia (Bert.) O. Kuntze trees are endangered in Brazil, and information on the diversity of soil spider families associated to these environments is practically inexistent. The present study was set up to evaluate the abundance and diversity of soil spider families in natural and reforested Araucaria forests, impacted or not by fire, and to identify the most efficient method to collect these organisms. The study was conducted in four areas: native forest with predominance of Araucaria (NF); Araucaria reforestation (R); Araucaria reforestation submitted to an accidental fire (RF); and native grass pasture with native Araucaria and submitted to an intense accidental fire (NPF). Considering both sampling methods (Monolith and Pitfall traps), 20 spider families were identified. The pitfall trap method was more effective as it captured 19 out of the 20 recorded families, while the Monolith method extracted only ten spider families. Spider family abundance and Shannon's diversity index (H) were affected by the employed collection method; the values for these attributes were always higher for the NF and lower for the NPF. Correspondence analysis (CA) showed a spatial separation among spider familiy assemblages from the different studied areas. It is suggested that changes in the abundance of soil spider families in Araucaria forests are mainly caused by recurrent human intervention over the last few years.<br>As florestas com Araucaria angustifolia (Bert.) O. Kuntze estão ameaçadas de extinção no Brasil, e são praticamente inexistentes as informações sobre a diversidade de famílias de aranhas de solo associadas nestes ambientes. O estudo teve o objetivo de avaliar, em florestas com araucária naturais e reflorestadas, impactadas ou não pela queima acidental, a abundância e diversidade de famílias de aranhas, além de identificar o método mais eficiente para coletar estes organismos. O estudo foi conduzido em quatro áreas: floresta nativa com predominância de araucária (NF); reflorestamento de araucária (R); reflorestamento de araucária submetido a incêndio acidental (RF); e pastagem natural com araucárias nativas e ocorrência de incêndio acidental (NPF). Considerando os dois métodos de amostragem (Monólito e armadilhas de solo), foram identificadas 20 famílias de aranhas associadas às áreas. O método das armadilhas de solo foi mais eficiente, capturando 19 das 20 famílias registradas, enquanto o do Monólito extraiu apenas dez destas famílias de aranhas. A abundância de famílias de aranhas e o índice de diversidade de Shannon (H) foram afetados pelo método de coleta utilizado, sendo os valores destes atributos sempre superiores na NF e inferiores na NPF. A análise de correspondência (AC) demonstrou que existe separação espacial entre as áreas estudadas. Sugere-se que as modificações na abundância de famílias de aranhas de solo sejam provocadas principalmente pelas intervenções antrópicas que as florestas de araucária vêm sofrendo nos últimos anos