The Spitzer c2d survey of large, nearby, interstellar clouds. X. The Chamaeleon II pre-main-sequence population as observed with IRAC and MIPS

We discuss the results from the combined IRAC and MIPS c2d Spitzer Legacy survey observations and complementary optical and NIR data of the Chamaeleon II (Cha II) dark cloud. We perform a census of the young population in an area of similar to 1.75 deg^(2) and study the spatial distribution and properties of the cloud members and candidate pre-main-sequence (PMS) objects and their circumstellar matter. Our census is complete down to the substellar regime (M approximate to 0.03 M☉). From the analysis of the volume density of the PMS objects and candidates we find two groups of objects with volume densities higher than 25 M☉ pc^(-3) and 5-10 members each. A multiplicity fraction of about 13% +/- 3% is observed for objects with separations 0.8" < θ < 6.0" (142-1065 AU). No evidence for variability between the two epochs of the c2d IRAC data set, Δt ~ 6 hr, is detected. We estimate a star formation efficiency of 1%-4%, consistent with the estimates for Taurus and Lupus, but lower than for Cha I. This might mean that different star formation activities in the Chamaeleon clouds reflect a different history of star formation. We also find that Cha II is turning some 6-7 M☉ into stars every Myr, which is low in comparison with the star formation rate in other c2d clouds. The disk fraction of 70%-80% that we estimate in Cha II is much higher than in other star-forming regions and indicates that the population in this cloud is dominated by objects with active accretion. Finally, the Cha II outflows are discussed; a new Herbig-Haro outflow, HH 939, driven by the classical T Tauri star Sz 50, has been discovered

C2D Spitzer-IRS spectra of disks around T Tauri stars: IV. Crystalline silicates

Aims. Dust grains in the planet-forming regions around young stars are expected to be heavily processed due to coagulation, fragmentation, and crystallization. This paper focuses on the crystalline silicate dust grains in protoplanetary disks for a statistically significant number of TTauri stars (96). Methods. As part of the cores to disks (c2d) legacy program, we obtained more than a hundred Spitzer/IRS spectra of TTauri stars, over a spectral range of 5-35 μm where many silicate amorphous and crystalline solid-state features are present. At these wavelengths, observations probe the upper layers of accretion disks up to distances of a dozen AU from the central object. Results. More than 3/4 of our objects show at least one crystalline silicate emission feature that can be essentially attributed to Mg-rich silicates. The Fe-rich crystalline silicates are largely absent in the c2d IRS spectra. The strength and detection frequency of the crystalline features seen at λ > 20 μm correlate with each other, while they are largely uncorrelated with the observational properties of the amorphous silicate 10 μm feature. This supports the idea that the IRS spectra essentially probe two independent disk regions: a warm zone (≤1 AU) emitting at ~ 10 μm and a much colder region emitting at λ > 20 μm (≤10 AU). We identify a crystallinity paradox, as the long-wavelength (λ > 20 m) crystalline silicate features are detected 3.5 times more frequently (~55% vs. ~15%) than the crystalline features arising from much warmer disk regions (λ ~ 10 μm). This suggests that the disk has an inhomogeneous dust composition within ~10 AU. The analysis of the shape and strength of both the amorphous 10 μm feature and the crystalline feature around 23 μm provides evidence for the prevalence of μm-sized (amorphous and crystalline) grains in upper layers of disks. Conclusions. The abundant crystalline silicates found far from their presumed formation regions suggest efficient outward radial transport mechanisms in the disks around TTauri stars. The presence of μm-sized grains in disk atmospheres, despite the short timescales for settling to the midplane, suggests efficient (turbulent) vertical diffusion, probably accompanied by grain-grain fragmentation to balance the expected efficient growth. In this scenario, the depletion of submicron-sized grains in the upper layers of the disks points toward removal mechanisms such as stellar winds or radiation pressure

A Spitzer c2d Legacy Survey to Identify and Characterize Disks with Inner Dust Holes

Understanding how disks dissipate is essential to studies of planet formation. However, identifying exactly how dust and gas dissipates is complicated due to difficulty in finding objects clearly in the transition of losing their surrounding material. We use Spitzer IRS spectra to examine 35 photometrically-selected candidate cold disks (disks with large inner dust holes). The infrared spectra are supplemented with optical spectra to determine stellar and accretion properties and 1.3mm photometry to measure disk masses. Based on detailed SED modeling, we identify 15 new cold disks. The remaining 20 objects have IRS spectra that are consistent with disks without holes, disks that are observed close to edge-on, or stars with background emission. Based on these results, we determine reliable criteria for identifying disks with inner holes from Spitzer photometry and examine criteria already in the literature. Applying these criteria to the c2d surveyed star-forming regions gives a frequency of such objects of at least 4% and most likely of order 12% of the YSO population identified by Spitzer. We also examine the properties of these new cold disks in combination with cold disks from the literature. Hole sizes in this sample are generally smaller than for previously discovered disks and reflect a distribution in better agreement with exoplanet orbit radii. We find correlations between hole size and both disk and stellar masses. Silicate features, including crystalline features, are present in the overwhelming majority of the sample although 10 micron feature strength above the continuum declines for holes with radii larger than ~7 AU. In contrast, PAHs are only detected in 2 out of 15 sources. Only a quarter of the cold disk sample shows no signs of accretion, making it unlikely that photoevaporation is the dominant hole forming process in most cases.Comment: 24 pages, 18 figures and 8 tables. Fixed a typo in Table

Sialadenoma papilliferum : bibliometric analysis

Sialadenoma papilliferum is a benign rare condition of salivary glands showing a characteristic papillary growth of the ductal epithelium that ends up being confused with more frequent lesions of the oral cavity. Objectives: To perform a bibliometric analysis of all articles about Sialadenoma papilliferum in the oral cavity and to add a singular case report of Sialadenoma in the lower lip. A total of 36 publications referring to Sialadenoma papilliferum in the oral cavity from the PubMed platform was reviewed. The specific data were collected, and a bibliometric analysis was performed using Microsoft Excel. The results obtained were then compared with this new case report. The people most affected with sialadenoma were white males at the average age of 56. The lesion was asymptomatic, usually white or red, with an average size of 1.4 cm, and the palate was by far the most affected site. The majority of the lesions were excised, and only two cases indicated recurrence. With surgical removal, Sialadenoma papilliferum has a favorable prognosis and no further treatment is required. Due to few recorded cases of recurrence, a long follow-up period is recommended to ensure that the lesion does not redevelop

The Spatial Distribution of Star Formation in the Solar Neighbourhood: Do all stars form in clusters?

We present a global study of low mass, young stellar object (YSO) surface densities in nearby (< 500 pc) star forming regions based on a comprehensive collection of Spitzer Space Telescope surveys. We show that the distribution of YSO surface densities in the solar neighbourhood is a smooth distribution, being adequately described by a lognormal function from a few to 10^3 YSOs per pc^2, with a peak at 22 stars/pc^2 and a dispersion of 0.85. We do not find evidence for multiple discrete modes of star-formation (e.g. clustered and distributed). Comparing the observed surface density distribution to previously reported surface density threshold definitions of clusters, we find that the fraction of stars in clusters is crucially dependent on the adopted definitions, ranging from 40 to 90%. However, we find that only a low fraction (< 26%) of stars are formed in dense environments where their formation/evolution (along with their circumstellar disks and/or planets) may be affected by the close proximity of their low-mass neighbours.Comment: 6 pages, 2 figures, MNRAS letters, accepte

The young population of the Chamaeleon II dark cloud

We discuss the results of the optical spectroscopic follow-up of pre-main-sequence (PMS) objects and candidates selected in the Chamaeleon II dark cloud based on data from the Spitzer Legacy survey "From Molecular Cores to Planet Forming Disks" (c2d) and from previous surveys. Our sample includes both objects with infrared excess selected according to c2d criteria and referred to as young stellar objects and other cloud members and candidates selected from complementary optical and near-infrared data. We characterize the sample of objects by deriving their physical parameters. The vast majority of objects have masses M ≤ 1 M_☉ and ages <6 Myr. Several of the PMS objects and candidates lie very close to or below the hydrogen-burning limit. A first estimate of the slope of the initial mass function in Cha II is consistent with that of other T associations. The star formation efficiency in the cloud (1%-4%) is consistent with our own estimates for Taurus and Lupus, but significantly lower than for Cha I. This might mean that different star formation activities in the Chamaeleon clouds may reflect a different history of star formation. We also find that the Cha II cloud is turning some 8 M_☉ into stars every megayear, which is less than the star formation rate in the other c2d clouds. However, the star formation rate is not steady and evidence is found that the star formation in Cha II might have occurred very rapidly. The Hα emission of the Cha II PMS objects, as well as possible correlations between their stellar and disk properties, is also investigated

Detection of anti -Rickettsia spp. antibodies in domestic chickens of extensive breeding in an endemic Detection of anti -Rickettsia spp. antibodies in domestic chickens of extensive breeding in an endemic area for spotted fever in the state of Rio Grande

Detecção de anticorpos anti

The impact of low erythrocyte density in human blood on the fitness and energetic reserves of the African malaria vector Anopheles gambiae

Background Anaemia is a common health problem in the developing world. This condition is characterized by a reduction in erythrocyte density, primarily from malnutrition and/or infectious diseases such as malaria. As red blood cells are the primary source of protein for haematophagous mosquitoes, any reduction could impede the ability of mosquito vectors to transmit malaria by influencing their fitness or that of the parasites they transmit. The aim of this study was to determine the impact of differences in the density of red blood cells in human blood on malaria vector (Anopheles gambiae sensu stricto) fitness. The hypotheses tested are that mosquito vector energetic reserves and fitness are negatively influenced by reductions in the red cell density of host human blood meals commensurate with those expected from severe anaemia. Methods Mosquitoes (An. gambiae s.s.) were offered blood meals of different packed cell volume(PCV) of human blood consistent with those arising from severe anaemia (15%) and normalPCV (50%). Associations between mosquito energetic reserves (lipid, glucose and glycogen)and fitness measures (reproduction and survival) and blood meal PCV were investigated. Results The amount of protein that malaria vectors acquired from blood feeding (indexed by haematin excretion) was significantly reduced at low blood PCV. However, mosquitoes feeding on blood of low PCV had the same oviposition rates as those feeding on blood of normal PCV, and showed an increase in egg production of around 15%. The long-term survival of An. gambiae s.s was reduced after feeding on low PCV blood, but PCV had no significant impact on the proportion of mosquitoes surviving through the minimal period required to develop and transmit malaria parasites (estimated as 14 days post-blood feeding). The impact of blood PCV on the energetic reserves of mosquitoes was relatively minor. Conclusions These results suggest that feeding on human hosts whose PCV has been depleted due to severe anaemia does not significantly reduce the fitness or transmission potential of malaria vectors, and indicates that mosquitoes may be able exploit resources for reproduction more efficiently from blood of low rather than normal PCV

Qualidade de vida e sobrecarga de mães de crianças com microcefalia

Introduction: Due to congenital infection, children with microcephaly have great limitations due to this condition. These limitations make the child need more health and home care. Generally, the mother becomes the main caretaker for this child, this role can lead to overload feelings that affect their quality of life. Objective: To analyze the role overload and the quality of life of mothers or primary caregiver of children with microcephaly related to congenital infection. Method: Cross-sectional, correlational study carried out with 105 participants from the state of Sergipe, Brazil, during the period from October 2017 to April 2018, through the application of questionnaires: sociodemographic, WHOQOL-Bref, and caregiver burden. For statistical analysis, ANOVA, t-test, and Pearson (r) tests were used. Results: All of the participants were females, 39 % were classified with severe role overload and 30.5% with intense role overload. The total average of this caregiver burden (49.47) presents a moderate to severe classification. There was a strong correlation (p&lt;0.0001) between the levels of their role overload and the domains of their quality of life, where the greatest damage was in the environmental (36.57) and physical (38.53) aspects. A significant and inversely proportional correlation (r=-0.547, p&lt;0.0001) was observed between the quality of life and the caregiver burden. Conclusion: Mothers suffer severe and intense caregiver overload that has a negative influence on their quality of life. Nursing can contribute to the creation and implementation of specific lines of care for these women emphasizing the promotion of physical and mental health to improve their quality of life.Introducción: Debido a la infección congénita, las niñas y los niños con microcefalia tienen grandes limitaciones en su estado de salud. Estas limitaciones hacen que necesiten más atención sanitaria y domiciliaria. Generalmente, la madre se convierte en la principal cuidadora y este papel puede llevar a la sobrecarga, con perjuicio para su calidad de vida. Objetivo: Analizar la sobrecarga de cuidado y la calidad de vida de las madres o personas cuidadoras primarias de niñas o niños con microcefalia, relacionada con infección congénita. Método: Estudio transversal, correlacional realizado con 105 participantes del estado de Sergipe, Brasil, de octubre de 2017 a abril de 2018, a través de la aplicación de los siguientes cuestionarios: sociodemográfico, el WHOQOL-Bref y escala de sobrecarga del cuidador. Para el análisis estadístico, se utilizaron ANOVA, prueba t y prueba Person (r). Resultados: Población totalmente femenina. El 39 % se clasificó con sobrecarga severa y el 30.5 % con sobrecarga intensa. La sobrecarga media total (49.47) indica una clasificación de moderada a grave. Hubo una fuerte asociación (p&lt;0.0001) entre los niveles de carga y los dominios de la calidad de vida, siendo los mayores daños ambientales (36.57) y físicos (38.53). Se observó una correlación significativa e inversamente proporcional (r=-0.547, p&lt;0.0001) entre la calidad de vida y la sobrecarga de la persona cuidadora cuidador. Conclusión: Las madres sufren una sobrecarga severa e intensa que influye negativamente en su calidad de vida. La enfermería puede contribuir para la creación e implementación de líneas de atención específicas para estas mujeres con énfasis en la promoción de la salud física y mental y la mejora de la calidad de vida.Introdução: Devido a infecção congênita, a criança com microcefalia possui grandes limitações de sua condição de saúde. Estas limitações fazem com que a criança necessite de maior atenção de saúde e domiciliar.  Geralmente, a mãe torna-se cuidadora principal desta criança, esse papel pode levar a sobrecarga com prejuízos em sua qualidade de vida. Objetivo: Analisar sobrecarga do cuidado e a qualidade de vida de mães ou cuidadoras principais de crianças com microcefalia relacionada à infecção congênita. Método: Estudo transversal, correlacional, realizado com 105 participantes do estado de Sergipe, Brasil, durante o período de outubro de 2017 a abril de 2018, através da aplicação questionários: sociodemográfico, WHOQOL-Bref e Sobrecarga do cuidador. Para análise estatística foram utilizados testes ANOVA, teste t e Person (r). Resultados: A totalidade dos participantes era do sexo feminino, 39 % foram classificadas com sobrecarga severa e 30,5% com sobrecarga intensa. A média total da sobrecarga (49,47) indica classificação de moderada à severa. Houve uma forte associação (p&lt;0,0001) entre os níveis de sobrecarga e os domínios da qualidade de vida, sendo o de maior prejuízo o ambiental (36,57) e o físico (38,53). Foi observada uma correlação significativa e inversamente proporcional (r=-0,547, p&lt;0,0001) entre a qualidade de vida e a sobrecarga do cuidador. Conclusão: As mães sofrem sobrecarga severa e intensa que pode levar a repercussões negativas em sua qualidade de vida. A enfermagem pode contribuir na criação e implementação de linhas de cuidados específicas para estas mulheres com ênfase na promoção da saúde física, mental e melhora da qualidade de vida