Extended States in a One-dimensional Generalized Dimer Model

The transmission coefficient for a one dimensional system is given in terms of Chebyshev polynomials using the tight-binding model. This result is applied to a system composed of two impurities located between $N$ sites of a host lattice. It is found that the system has extended states for several values of the energy. Analytical expressions are given for the impurity site energy in terms of the electron's energy. The number of resonant states grows like the number of host sites between the impurities. This property makes the system interesting since it is a simple task to design a configuration with resonant energy very close to the Fermi level $E_F$.Comment: 4 pages, 3 figure

Numerical Modelling of Caseless Ammunition with Coreless Bullet in Internal Ballistics

In the search of a new weapon for combat in short range, it is proposed the use of a new experimentally designed 7.62 mm calibre ammunition with a lighter weight (caseless-coreless). This can be used in carbine assault rifles with short barrel or pistols. In this work, the compressible gases flowing through the gun barrel caused by the proposed ammunition were experimentally and numerically analysed. The Large Eddy Simulation was used for the numerical simulation, considering a compressible and turbulent flow, with the chemical species transport model and a complete conversion of the propellant reaction. Variations in pressure and temperature were compared with the results obtained from a conventional 7.62 mm full metal jacket (FMJ) ammunition. Results of ballistic experimental tests and numerical simulations were similar than those of the 9 mm x 19 mm FMJ ammunitions, showing feasibility for the development of new weapons intended for operations of short range shots.Defence Science Journal, Vol. 65, No. 3, May 2015, pp.203-207, DOI: http://dx.doi.org/10.14429/dsj.65.851

Numerical and Experimental Analysis of Sound Suppressor for a 5.56 mm Calibre

A sound suppressor is an internal or external device coupled to the barrel of a firearm. Its development has been historically related to the negative effects produced by the noise. This article presents the numerical and experimental analysis of a sound suppressor for a 5.56 mm caliber rifle. It was designed, manufactured, and tested inside a shooting tunnel for 911 m/s and 344 m/s velocities. Three geometric configurations with curved deflectors, conical deflectors, and finally with a reactive spiral capable of dissipating the acoustic wave were compared considering reactive and dissipative systems. The attenuation of the sound inside the silencer depends directly on the reduction of the projectile wave velocity and the deflagration of the gases at the instant of firing. Then the MIL-STD-1474E standard was used to carry out the experiments. The results in the computational numerical simulation show an average value of 143 dB for the considered three models, the Sound Pressure Level in the reactive core model decreased by 25% with respect to other proposals, which have an average value of 141 dB. These results can be useful to improve in the design of sound suppressors based on the needs of the users and under the specific characteristics of each weapon ballistic.&nbsp

Insulin resistance and its association with the components of the metabolic syndrome among obese children and adolescents

<p>Abstract</p> <p>Background</p> <p>Insulin resistance is the primary metabolic disorder associated with obesity; yet little is known about its role as a determinant of the metabolic syndrome in obese children. The aim of this study is to assess the association between the degree of insulin resistance and the different components of the metabolic syndrome among obese children and adolescents.</p> <p>Methods</p> <p>An analytical, cross-sectional and population-based study was performed in forty-four public primary schools in Campeche City, Mexico. A total of 466 obese children and adolescents between 11-13 years of age were recruited. Fasting glucose and insulin concentrations, high density lipoprotein cholesterol, triglycerides, waist circumference, systolic and diastolic blood pressures were measured; insulin resistance and metabolic syndrome were also evaluated.</p> <p>Results</p> <p>Out of the total population studied, 69% presented low values of high density lipoprotein cholesterol, 49% suffered from abdominal obesity, 29% had hypertriglyceridemia, 8% presented high systolic and 13% high diastolic blood pressure, 4% showed impaired fasting glucose, 51% presented insulin resistance and 20% metabolic syndrome. In spite of being obese, 13% of the investigated population did not present any metabolic disorder. For each one of the components of the metabolic syndrome, when insulin resistance increased so did odds ratios as cardiometabolic risk factors.</p> <p>Conclusions</p> <p>Regardless of age and gender an increased degree of insulin resistance is associated with a higher prevalence of disorders in each of the components of the metabolic syndrome and with a heightened risk of suffering metabolic syndrome among obese children and adolescents.</p

The SlCBL10 calcineurin B-like protein ensures plant growth under salt stress by regulating Na+ and Ca2+ homeostasis

[EN] Characterization of a new tomato (Solanum lycopersicum) T-DNA mutant allowed for the isolation of the CALCINEURIN B-LIKE PROTEIN 10 (SlCBL10) gene whose lack of function was responsible for the severe alterations observed in the shoot apex and reproductive organs under salinity conditions. Physiological studies proved that SlCBL10 gene is required to maintain a proper low Na+/Ca2+ ratio in growing tissues allowing tomato growth under salt stress. Expression analysis of the main responsible genes for Na+ compartmentalization (i.e. Na+/H+ EXCHANGERs, SALT OVERLY SENSITIVE, HIGH-AFFINITY K+ TRANSPORTER 1; 2, H+-pyrophosphatase AVP1 [SlAVP1] and V-ATPase [SlVHA-A1]) supported a reduced capacity to accumulate Na+ in Slcbl10 mutant leaves, which resulted in a lower uploading of Na+ from xylem, allowing the toxic ion to reach apex and flowers. Likewise, the tomato CATION EXCHANGER 1 and TWO-PORE CHANNEL 1 (SlTPC1), key genes for Ca2+ fluxes to the vacuole, showed abnormal expression in Slcbl10 plants indicating an impaired Ca2+ release from vacuole. Additionally, complementation assay revealed that SlCBL10 is a true ortholog of the Arabidopsis (Arabidopsis thaliana) CBL10 gene, supporting that the essential function of CBL10 is conserved in Arabidopsis and tomato. Together, the findings obtained in this study provide new insights into the function of SlCBL10 in salt stress tolerance. Thus, it is proposed that SlCBL10 mediates salt tolerance by regulating Na+ and Ca2+ fluxes in the vacuole, cooperating with the vacuolar cation channel SlTPC1 and the two vacuolar H+-pumps, SlAVP1 and SlVHA-A1, which in turn are revealed as potential targets of SlCBL10.This study was supported by grants from the Plant KBBE Program (EUI2009-04074), the Spanish Ministerio de Economia y Competitividad (AGL2012-40150, AGL2015-64991-C3-1-R/2-R/3-R, and BIO2016-79187-R), as well as the French National Research Agency ENDOREPIGEN project. A.O.-A. was supported by a PhD fellowship from the Ministerio de Economia y Competitividad (BIO2009-11484).Egea, I.; Pineda Chaza, BJ.; Ortiz Atienza, A.; Plasencia, F.; Drevensek, S.; García Sogo, B.; Yuste-Lisbona, FJ.... (2018). The SlCBL10 calcineurin B-like protein ensures plant growth under salt stress by regulating Na+ and Ca2+ homeostasis. PLANT PHYSIOLOGY. 176(2):1676-1693. https://doi.org/10.1104/pp.17.01605S16761693176

Prevalence of anemia and deficiency of iron, folic acid, and zinc in children younger than 2 years of age who use the health services provided by the Mexican Social Security Institute

<p>Abstract</p> <p>Background</p> <p>In Mexico, as in other developing countries, micronutrient deficiencies are common in infants between 6 and 24 months of age and are an important public health problem. The objective of this study was to determine the prevalence of anemia and of iron, folic acid, and zinc deficiencies in Mexican children under 2 years of age who use the health care services provided by the Mexican Institute for Social Security (IMSS).</p> <p>Methods</p> <p>A nationwide survey was conducted with a representative sample of children younger than 2 years of age, beneficiaries, and users of health care services provided by IMSS through its regular regimen (located in urban populations) and its Oportunidades program (services offered in rural areas). A subsample of 4,955 clinically healthy children was studied to determine their micronutrient status. A venous blood sample was drawn to determine hemoglobin, serum ferritin, percent of transferrin saturation, zinc, and folic acid. Descriptive statistics include point estimates and 95% confidence intervals for the sample and projections for the larger population from which the sample was drawn.</p> <p>Results</p> <p>Twenty percent of children younger than 2 years of age had anemia, and 27.8% (rural) to 32.6% (urban) had iron deficiency; more than 50% of anemia was not associated with low ferritin concentrations. Iron stores were more depleted as age increased. Low serum zinc and folic acid deficiencies were 28% and 10%, respectively, in the urban areas, and 13% and 8%, respectively, in rural areas. The prevalence of simultaneous iron and zinc deficiencies was 9.2% and 2.7% in urban and rural areas. Children with anemia have higher percentages of folic acid deficiency than children with normal iron status.</p> <p>Conclusion</p> <p>Iron and zinc deficiencies constitute the principal micronutrient deficiencies in Mexican children younger than 2 years old who use the health care services provided by IMSS. Anemia not associated with low ferritin values was more prevalent than iron-deficiency anemia. The presence of micronutrient deficiencies at this early age calls for effective preventive public nutrition programs to address them.</p

Pedagogia crítica e direitos humanos: fundamentos para uma proposta pedagógico-crítica em direitos humanos

Este artigo reflete sobre a necessidade de encontrar uma teoria pedagógica que ofereça sustentação à ação educativa em Direitos Humanos, apresentando uma proposta pedagógico-crítica alicerçada nos pressupostos da teoria e da pedagogia críticas, privilegiando a pedagogia freireana, numa perspectiva atualizada para os Direitos Humanos. Nesse sentido, o trabalho tem o propósito de discutir um fundamento teórico-crítico para a Educação em Direitos Humanos, buscando novas formas de investigação e de análise para sua compreensão, apropriando-se de conceitos críticos como conscientização, autonomia, diálogo e emancipação. Finalmente, considera que uma prática pedagógica crítica em Direitos Humanos contribui para a leitura do mundo do excluído, para sua inclusão na sociedade e para a compreensão de que é possível desconstruir relações e práticas sociais injustas.(undefined

In silico transcriptional regulation and functional analysis of dengue shock syndrome associated SNPs in PLCE1 and MICB genes

YesSingle nucleotide polymorphisms (SNPs) in PLCE1 and MICB genes increase risk for the development of dengue shock syndrome (DSS). We used Bioinformatics tools to predict alterations at the transcriptional and posttranslational levels driven by PLCE1 and MICB SNPs associated with DSS. Functional and phenotypic analysis conducted to determine deleterious SNPs and impact of amino acid substitution on the structure and function of proteins identified rs2274223 (H1619R) as deleterious to protein coding as it induces structural change in the C2 domain of PLCε, with the mutant residue more positively charged than the wild-type residue (RMSD score, 1.75 Å).Moreover, rs2274223 condenses the chromatinrepressing PLCε expression in DSS. Briefly, this study presents the impact of a single nucleotide transition at SNPs associated with DSS on differential protein binding patterns with PLCE1 and MICB genes and on protein structure modification and their possible role in the pathogenesis of DSS