Recent, independent and anthropogenic origins of Trypanosoma cruzi hybrids.

The single celled eukaryote Trypanosoma cruzi, a parasite transmitted by numerous species of triatomine bug in the Americas, causes Chagas disease in humans. T. cruzi generally reproduces asexually and appears to have a clonal population structure. However, two of the six major circulating genetic lineages, TcV and TcVI, are TcII-TcIII inter-lineage hybrids that are frequently isolated from humans in regions where chronic Chagas disease is particularly severe. Nevertheless, a prevalent view is that hybridisation events in T. cruzi were evolutionarily ancient and that active recombination is of little epidemiological importance. We analysed genotypes of hybrid and non-hybrid T. cruzi strains for markers representing three distinct evolutionary rates: nuclear GPI sequences (n = 88), mitochondrial COII-ND1 sequences (n = 107) and 28 polymorphic microsatellite loci (n = 35). Using Maximum Likelihood and Bayesian phylogenetic approaches we dated key evolutionary events in the T. cruzi clade including the emergence of hybrid lineages TcV and TcVI, which we estimated to have occurred within the last 60,000 years. We also found evidence for recent genetic exchange between TcIII and TcIV and between TcI and TcIV. These findings show that evolution of novel recombinants remains a potential epidemiological risk. The clearly distinguishable microsatellite genotypes of TcV and TcVI were highly heterozygous and displayed minimal intra-lineage diversity indicative of even earlier origins than sequence-based estimates. Natural hybrid genotypes resembled typical meiotic F1 progeny, however, evidence for mitochondrial introgression, absence of haploid forms and previous experimental crosses indicate that sexual reproduction in T. cruzi may involve alternatives to canonical meiosis. Overall, the data support two independent hybridisation events between TcII and TcIII and a recent, rapid spread of the hybrid progeny in domestic transmission cycles concomitant with, or as a result of, disruption of natural transmission cycles by human activities

Machine tool Verification According to Machine Configuration

AbstractMachine Tool verification is an important issue for metrology. In recent years several efforts has being done in order to increase the methods reliabilities. However, geometrical verification on shop floor and big machines has not being explore as widely, leaving work possibilities open. This article presents a ball bar-based formulae determination method for the 21 MT geometrical errors taking into account the specific machine configuration, as well as its verification and validation

Annual distribution of the Sun’s angular positions, study at 21 degrees of latitude

Por experiencia sabemos que la posición del Sol, relativa a un observador situado sobre la superficie de la Tierra, cambia según el día del año y la latitud en la que se encuentra dicho observador. En general, el Sol describe, en la bóveda celeste, una trayectoria diferente para cada día del año que está determinada por los ángulos del azimut y del zenit. El cálculo analítico para determinar la posición angular en cualquier momento (hora solar) resulta ser una tarea abrumadora. En el lenguaje de programación del software Mathematica®, desarrollamos un código que nos permite determinar, con precisión temporal de 60 segundos (1 minuto), y para cualquier latitud, los ángulos del azimut y del zenit que determinan la posición del Sol a lo largo de un año. Con el propósito de presentar resultados de interés en situaciones prácticas, en este trabajo estudiamos resultados de la distribución anual de las posiciones angulares y las horas de luz en la latitud 21 grados (correspondiente a la Ciudad de Mérida). Los resultados muestran que el Sol sigue trayectorias con inclinación hacia el norte para días de más de 12 horas de luz solar, y hacia el sur para días de menos de 12 horas de luz solar. La información que se presenta puede utilizarse en diversas situaciones, por ejemplo, para un aprovechamiento óptimo de las horas de luz de colectores solares, sistemas autónomos de seguimiento solar, ubicación y orientación de paneles solares, así como para el diseño y orientación espacial de casas habitación en las que se desee que la radiación solar incida de manera parcial sobre paredes verticales y aumentar el confort térmico.It is well know that the Sun position, measured over the heart surface is a function of the latitude and the hour of a particular day. Usually, the Sun follows a different path from one day to the next, and this is determined by the azimuth and zenith angles. The analytical calculations for determining the angular position at any time (solar hour) are an overwhelming task. We use the Mathematica® software to write a home code for determining at any time (in intervals of one minute) and latitude, the azimuth and zenith angles of the Sun for every day of the year. In order to show general results of interest, in this work we present the annual distribution of the angular positions and the length of the day (hours of light) for the 21 degrees of latitude. This information could be used for optimizing the orientation of solar panels and collectors and for the design of cheap houses where the walls can be exposed to the minimal solar incidence.Peer Reviewe

Physiological responses to acute cold exposure in young lean men

The aim of this study was to comprehensively describe the physiological responses to an acute bout of mild cold in young lean men (n = 11, age: 23 ± 2 years, body mass index: 23.1 ± 1.2 kg/m2) to better understand the underlying mechanisms of non-shivering thermogenesis and how it is regulated. Resting energy expenditure, substrate metabolism, skin temperature, thermal comfort perception, superficial muscle activity, hemodynamics of the forearm and abdominal regions, and heart rate variability were measured under warm conditions (22.7 ± 0.2ÊC) and during an individualized cooling protocol (air-conditioning and water cooling vest) in a cold room (19.4 ± 0.1ÊC). The temperature of the cooling vest started at 16.6ÊC and decreased ~ 1.4ÊC every 10 minutes until participants shivered (93.5 ± 26.3 min). All measurements were analysed across 4 periods: warm period, at 31% and at 64% of individualÂs cold exposure time until shivering occurred, and at the shivering threshold. Energy expenditure increased from warm period to 31% of cold exposure by 16.7% (P = 0.078) and to the shivering threshold by 31.7% (P = 0.023). Fat oxidation increased by 72.6% from warm period to 31% of cold exposure (P = 0.004), whereas no changes occurred in carbohydrates oxidation. As shivering came closer, the skin temperature and thermal comfort perception decreased (all P<0.05), except in the supraclavicular skin temperature, which did not change (P>0.05). Furthermore, the superficial muscle activation increased at the shivering threshold. It is noteworthy that the largest physiological changes occurred during the first 30 minutes of cold exposure, when the participants felt less discomfort.The study was supported by the Spanish Ministry of Economy and Competitiveness (PTA 12264-I), Fondo de InvestigacioÂn Sanitaria del Instituto de Salud Carlos III (PI13/01393), and Retos de la Sociedad (DEP2016-79512-R), Fondos Estructurales de la UnioÂn Europea (FEDER), by the Spanish Ministry of Education (FPU 13/04365 and 15/04059), by the FundacioÂn Iberoamericana de NutricioÂn (FINUT), by the Redes temaÂticas de investigacioÂn cooperativa RETIC (Red SAMI

Chitosan-Gold Nanoparticle Composites for Biomedical Application

The aim of this work is to synthesize chitosan-gold nanoparticles films by direct chemical reduction of HAuCl4 in a chitosan solution and to investigate the influence of gold nanoparticles concentration on the structure of films, conductivity and healing effect on mice skin after surgery. Results obtained have shown that new chitosan-gold nanoparticle-collagen bionananocomposites demonstrated better healing effect on the mice skin after surgery than control performed on commercial TheraFormTM material. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3540

A matrix pencil approach to the existence of compactly supported reconstruction functions in average sampling

The aim of this work is to solve a question raised for average sampling in shift-invariant spaces by using the well-known matrix pencil theory. In many common situations in sampling theory, the available data are samples of some convolution operator acting on the function itself: this leads to the problem of average sampling, also known as generalized sampling. In this paper we deal with the existence of a sampling formula involving these samples and having reconstruction functions with compact support. Thus, low computational complexity is involved and truncation errors are avoided. In practice, it is accomplished by means of a FIR filter bank. An answer is given in the light of the generalized sampling theory by using the oversampling technique: more samples than strictly necessary are used. The original problem reduces to finding a polynomial left inverse of a polynomial matrix intimately related to the sampling problem which, for a suitable choice of the sampling period, becomes a matrix pencil. This matrix pencil approach allows us to obtain a practical method for computing the compactly supported reconstruction functions for the important case where the oversampling rate is minimum. Moreover, the optimality of the obtained solution is established

Tuberculosis vaccine candidates based on mycobacterial cell envelope components

Even after decades searching for a new and more effective vaccine against tuberculosis, the scientific community is still pursuing this goal due to the complexity of its causative agent, Mycobacterium tuberculosis (Mtb). Mtb is a microorganism with a robust variety of survival mechanisms that allow it to remain in the host for years. The structure and nature of the Mtb envelope play a leading role in its resistance and survival. Mtb has a perfect machinery that allows it to modulate the immune response in its favor and to adapt to the host's environmental conditions in order to remain alive until the moment to reactivate its normal growing state. Mtb cell envelope protein, carbohydrate and lipid components have been the subject of interest for developing new vaccines because most of them are responsible for the pathogenicity and virulence of the bacteria. Many indirect evidences, mainly derived from the use of monoclonal antibodies, support the potential protective role of Mtb envelope components. Subunit and DNA vaccines, lipid extracts, liposomes and membrane vesicle formulations are some examples of technologies used, with encouraging results, to evaluate the potential of these antigens in the protective response against Mtb.Fil: Sarmiento, M.E.. Universiti Sains Malaysia; MalasiaFil: Alvarez, N.. Public Health Research Institute; Estados UnidosFil: Chin, K.L.. Universiti Sains Malaysia; MalasiaFil: Bigi, Fabiana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Agrobiotecnología y Biología Molecular. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Tirado, Y.. No especifíca;Fil: García, M.A.. No especifíca;Fil: Anis, F.Z.. Universiti Sains Malaysia; MalasiaFil: Norazmi, M.N.. Universiti Sains Malaysia; MalasiaFil: Acosta, A.. Universiti Sains Malaysia; Malasi