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Early prediction of the final size of any epidemic and in particular for Zika disease outbreaks can be useful for health authorities in order to plan the response to the outbreak. The Richards model is often been used to estimate epidemiological parameters for arboviral diseases based on the reported cumulative cases in single- and multi-wave outbreaks. However, other non-linear models can also fit the data as well. Typically, one follows the so called post selection estimation procedure, i.e., selects the best fitting model out of the set of candidate models and ignores the model uncertainty in both estimation and inference since these procedures are based on a single model. In this paper we focus on the estimation of the final size and the turning point of the epidemic and conduct a real-time prediction for the final size of the outbreak using several non-linear models in which these parameters are estimated via model averaging. The proposed method is applied to Zika outbreak data in four cities from Colombia, during the outbreak ocurred in 2015–2016.
Recently, new views of the current status of δ Scuti stars have been developed by Rodríguez & Breger (2001) who carried out an excellent review, listing 8 pre-main-sequence (PMS) δ Scuti candidates and examined the possibility of the existence of PMS δ Scuti variable stars. Here we discuss the nature of 4 stars from their list: 2 said to be members of NGC 2264 and 2 of NGC 6823.
The steep spectrum of IRAS F02044+0957 was obtained with the RATAN-600 radio telescope at four frequencies. Optical spectroscopy of the system components was carried out with the 2.1m telescope of the Guillermo Haro Observatory. The observational data allow us to conclude that this object is a pair of interacting galaxies, a LINER and an H II galaxy, at z = 0.093.
As the first step of the Multiwavelength AGN Survey (MWAS), we have started the FIRST-APM QSO Survey (FAQS). The main goal of FAQS is to compile the most complete sample of bright QSOs, located in the area of the sky covered by the Second Byurakan Survey (SBS). Here we report the current status of an ongoing study based on the cross-identification of the FIRST radio catalog and the APM optical catalog. The overlapping sky area between FIRST and SBS is about 700 deg2. The compiled list of sources for this overlapping region contains ~ 400 quasar candidates brighter than . About 90 objects were already spectroscopically classified. During 1999-2000, we observed spectroscopically more than 150 FAQS objects with the 2.1m telescope of the Guillermo Haro Astropysical Observatory (GHAO). We have found 51 new QSOs (4 BAL QSOs), 13 Seyfert Galaxies (5 NLSyl’s), 23 emission line galaxies, 3 BL Lac objects and 57 stars.
The Antillean manatee Trichechus manatus manatus is categorized as Endangered on the IUCN Red List but little is known about the status of the species in Cuba. Marine protected areas can contribute to manatee conservation in Cuba but the effectiveness of these areas may be jeopardized by a lack of information regarding appropriate design and management. We developed an index of manatee occurrence in the Fauna Refuge Ciénaga de Lanier, Isla de la Juventud, to assess patterns of manatee use in the reserve. We completed 26 field trips during November 2007–October 2013, with a total of 147 survey days. Manatee presence was detected on 47% of survey days and in 96% of field trips; 133 individuals were recorded in 93 sightings. The index of manatee occurrence varied between trips, suggesting a discontinuous use of the area. The mean group size was 1.4 individuals (range 1–5), and calves were observed in 13% of sightings. Observations of manatee behaviour, occurrence and habitat characteristics indicate the importance of the study area as a resting place, refuge and source of fresh water. We recommend that manatee protection be strengthened to avoid human-related mortality and to ensure that the habitats that provide critical resources are given special consideration in future management plans.
Thirty-two lambs (n = 8 per treatment) were fed a total mixed ration (TMR) formulated either with palm oil (CTRL; 34 g palm oil/kg TMR) or flaxseed (FS) (85 g FS/kg TMR) alone or enriched with quercetin (QCT, 34 g palm oil plus 2 g QCT/kg TMR; FS-QCT, 85 g FS plus 2 g QCT/kg TMR). The animals were slaughtered after being fed for at least 5 weeks with the experimental diets and samples of ruminal contents and ruminal liquid were collected for quantitative real-time polymerase chain reaction analyses of ruminal microbial species and fatty acid profile or in vitro fermentation, respectively. Results demonstrated that Butyrivibrio vaccenic acid (VA) and Butyrivibrio stearic acid (SA) producing bacteria copy numbers were decreased when FS was added to the diet of fattening lambs, which seemed to be in agreement with numerically (but not significantly) lower values for gas production, methane production and butyric acid during in vitro incubation. Ciliate protozoa were significantly enhanced by QCT, which was in accordance with numerically (but not significantly) higher values for in vitro methane production. Moreover, the modifications observed in ruminal microbial populations (Butyrivibrio and ciliate protozoa) when FS and QCT were included together (but not separately) in the diet of fattening lambs were probably related to a trend towards significantly higher values of rumenic acid (RA) in ruminal content. In conclusion, when FS and QCT were administered together in the diet of fattening lambs quantitative changes in the ruminal microbiota were observed, which might have promoted an increment of RA concentration in ruminal contents.
Gas tungsten arc welding-tungsten inert gas (GTAW-TIG) is focused in literature as an alternative choice for joining high strength low alloy steels; this study is performed to compare the differences between gas metal arc welding-metal inert gas (GMAW-MIG) and GTAW welding processes. The aim of this study is to characterize microstructure of dissimilar transformation induced plasticity steels (TRIP) and martensitic welded joints by GMAW and GTAW welding processes. It was found that GMAW process lead to relatively high hardness in the HAZ of TRIP steel, indicating that the resultant microstructure was martensite. In the fusion zone (FZ), a mixture of phases consisting of bainite, ferrite and small areas of martensite were present. Similar phase’s mixtures were found in FZ of GTAW process. The presence of these mixtures of phases did not result in mechanical degradation when the GTAW samples were tested in lap shear tensile testing as the fracture occurred in the heat affected zone. In order to achieve light weight these result are benefits which is applied an autogenous process, where it was shown that without additional weight the out coming welding resulted in a high quality bead with homogeneous mechanical properties and a ductile morphology on the fracture surface. Scanning electron microscopy (SEM) was employed to obtain information about the specimens that provided evidence of ductile morphology.
We investigate the ‘gender-congruency’ effect during a spoken-word recognition task using the visual world paradigm. Eye movements of Italian–Spanish bilinguals and Spanish monolinguals were monitored while they viewed a pair of objects on a computer screen. Participants listened to instructions in Spanish (encuentra la bufanda / ‘find the scarf’) and clicked on the object named in the instruction. Grammatical gender of the objects’ name was manipulated so that pairs of objects had the same (congruent) or different (incongruent) gender in Italian, but gender in Spanish was always congruent. Results showed that bilinguals, but not monolinguals, looked at target objects less when they were incongruent in gender, suggesting a between-language gender competition effect. In addition, bilinguals looked at target objects more when the definite article in the spoken instructions provided a valid cue to anticipate its selection (different-gender condition). The temporal dynamics of gender processing and cross-language activation in bilinguals are discussed.
Duplex stainless steels are commonly used for various applications owing to their superior corrosion resistance and/or strength. They have ferromagnetic behavior together with a good thermal conductivity and a lower thermal expansion as a result of higher ferrite content than austenitic steels. Their ferrite matrix suffers a decomposition process during aging in the temperature range 650-950° C producing precipitation of austenite, σ and χ, carbides and nitrides. These intermetallic phases are known to be deleterious for corrosion resistance and mechanical properties.
In this work the effect of aging time during isothermal treatment at 850°C and 900°C on the microstructure of SAF 2205 Duplex Stainless Steels welded plates has been investigated. The aim of this work is to determine the morphology of σ phase, and perform a quantitative analysis of the precipitation process.
Submerged Arc Welding is used for processing. It produces a high content of δ ferrite in the heat affected zone and low content of austenite in the weld. Microstructural examination shows that the σ phase precipitates at δ ferrite/γ interphases. Longer aging treatments give rise to an increase of volume fraction together with a coarser morphology.
Microbe-associated molecular pattern (MAMP)-triggered immunity (MTI) is an important component of the plant innate immunity response to invading pathogens. Although several MTI responses can be measured in different plant species, their magnitude is probably plant species specific and even cultivar specific. In this study, a genome-wide transcriptome analysis of two soybean parental lines and two progeny lines treated for 30 min with the MAMPs flg22 and chitin was carried out. This analysis revealed a clear variation in gene expression, under both untreated and flg22+chitin-treated conditions. In addition, genes with potential additive and non-additive effects were identified in the two progeny lines, with several of these genes having a potential function in the control of innate immunity. The data presented herein represent the basis for further functional analysis that can lead to a better understanding of the soybean innate immunity response.
Today, stainless steel is widely used in automotive industry due to its high impact resistance, corrosion resistance and light weight. This paper present the research carried out to study the differences between microstructure and mechanical properties of 409 and 308 stainless steel sheets, each joints by gas tungsten arc welding (GTAW). For each of weldments, detailed analysis was conducted on the chemical composition, microstructure characteristics and mechanical properties of base metal (BM), heat affected zone (HAZ) and fusion zone (FZ). Scanning electron microscopy (SEM) and optical microscopy were used to analyze microstructural changes and mechanical properties, including microhardness and tensile test. This study can be a practical guide in the selection of other materials in order to determine the important to use in structural automotive industry.
Duplex stainless steels (DSS) have good mechanical and corrosion resistance properties which allow their application in very aggressive environments. However, their aging at 600–1000 °C causes the precipitation of dangerous intermetallic phases, resulting in serious detrimental effects on their interesting properties. These secondary phases are structural discontinuities which act as preferential cracks initiation sites and their negative effect is especially highlighted on toughness. For these reasons, many standards related to the manufacturing of DSS require the microstructure of these steels "free from intermetallics". In this paper, the effect of isothermal heat treatments on the impact toughness in two Duplex steels (SAF 2205 and Zeron®100) has been investigated, in order to study the influence of different amount of secondary phases on the toughness response.
The effect of friction stir welding (FSW) on the resultant microstructures in the welded nugget (WN), thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ) and base metal (BM) of a TRIP-780 steel was investigated in this work. Color tint etching was used in the welded regions to disclose the exhibited microstructural constituents. In addition, significant fine grain size material was found in the WN regions. It was found that is considered to have experienced severe plastic deformation due to interaction with the welding tool pin lead to a drop in mechanical properties. Lap shear tensile testing indicated that the steel shear tension strength in the welded condition dropped compared with the BM. Microhardness profiles of the welded regions indicated that the hardness in both the WN and TMAZ were relatively elevated suggesting the development of martensite in these regions. In particular, the WN was found to shear fracture with uniformly distributed elongation shear dimples.
Gas metal arc welding (GMAW) of a sub-frame automotive industry was studied, applying a design of experiment (DOE) in Minitab and Matlab software. Voltages, welding speed and wire feed speed was defined as input variables; legs and throats of welding were output variables in millimeters dimension. The requirement for GMAW process was to achieve complete penetration, minimum values acceptable of legs and throat indicated in AWS D8.8M:2007 “Specification for automotive weld quality-arc welding” without any discontinuity, like undercutting or porosity. The required of quality were difficult to achieve due to the materials have microstructural and mechanical properties different, the SAE 1008 has 279MPa for ultimate tensile strength (UTS) and the microstructure consist of ferrite matrix with some small areas of cementite, while SAE 2340 has 456MPa of UTS with a combination of perlite and ferrite. It was possible obtain good quality welds with proper geometry and defect free with help to design of experiment. The conditions needed were a combination of parameters to not obtained significant change microestructural characterized by optical microscopy, stereoscopy and scanning electron microscopy.
In a recent study, Lew-Williams and Fernald (2007) showed that native Spanish speakers use grammatical gender
information encoded in Spanish articles to facilitate the processing of upcoming
nouns. In this article, we report the results of a study investigating whether
grammatical gender facilitates noun recognition during second language (L2)
processing. Sixteen monolingual Spanish participants (control group) and 18
English-speaking learners of Spanish (evenly divided into high and low Spanish
proficiency) saw two-picture visual scenes in which items matched or did not
match in gender. Participants’ eye movements were recorded while they
listened to 28 sentences in which masculine and feminine target items were
preceded by an article that agreed in gender with the two pictures or agreed
only with one of the pictures. An additional group of 15 Italian learners of
Spanish was tested to examine whether the presence of gender in the first
language (L1) modulates the degree to which gender is used during L2 processing.
Data were analyzed by comparing the proportion of eye fixations on the objects
in each condition. Monolingual Spanish speakers looked sooner at the referent on
different-gender trials than on same-gender trials, replicating results reported
in past literature. Italian-Spanish bilinguals exhibited a gender anticipatory
effect, but only for the feminine condition. For the masculine condition,
participants waited to hear the noun before identifying the referent. Like the
Spanish monolinguals, the highly proficient English-Spanish speakers showed
evidence of using gender information during online processing, whereas the less
proficient learners did not. The results suggest that both proficiency in the L2
and similarities between the L1 and the L2 modulate the usefulness of
morphosyntactic information during speech processing.
This article presents an analysis of the heat generated by welding two different metals by friction. The welded samples were a DP600 steel and aluminum 6063. To perform this analysis it study the heat conducted in this system using Fourier’s Law and respective specific heat of each metal. We analyzed the integral equations that make up the model and the heat flow analysis to predict the optimal combination of alloys, in an ideal process.
In order to increase the wettability and capillary forces of the filler metal between micro-cracking and micro-porous on the fracture surfaces of 304 stainless steels, methods of impregnation of Si and growth of Ni nanoparticles were used. These nanoparticles have a role inside the Transient Liquid Phase (TLP) and the substrate when using Brazing process. TLP can react with the nanoparticles previously deposited between micro-cracking and micro-porous and therefore promotes the nucleation and growth sites of phases and decreases the formation of eutectic structures. This method increases the effectiveness of metallic components reparation using Brazing process. Such effectiveness is indicated by an inspection of microstructural failure analysis, as a first stage, in the covered zone by the filler metal.