First result from the Alpha Magnetic Spectrometer on the International Space Station: precision measurement of the positron fraction in primary cosmic rays of 0.5-350 GeV

A precision measurement by the Alpha Magnetic Spectrometer on the International Space Station of the positron fraction in primary cosmic rays in the energy range from 0.5 to 350 GeV based on 6.8 × 10(6) positron and electron events is presented. The very accurate data show that the positron fraction is steadily increasing from 10 to ∼ 250  GeV, but, from 20 to 250 GeV, the slope decreases by an order of magnitude. The positron fraction spectrum shows no fine structure, and the positron to electron ratio shows no observable anisotropy. Together, these features show the existence of new physical phenomena.

Farmer's views and values to focus on cattle conservation policies: the case of eight European countries

Our aim was to identify elements useful in designing policies and programmes for conservation of farm animal genetic resources, taking as case study a group of European local cattle breeds. We first investigated the implications of differences among countries in the policies and programmes to be developed. Secondly, we analysed key elements common to countries, which may affect local breed viability. We used the herd size trend expected by the farmer in the near future as an indicator of breed viability. Fifteen breeds, for a total of 355 farms, were surveyed. To take into account the multiple factors influencing breeds' demographic trends, the questionnaire included economical, technical and social aspects. Among the major differences across countries was the perception of the farmer on the value attributed to the local breed by society. Concerning the elements common to countries and their association to breed viability, the greater the collaboration among farmers and the stakeholders' appreciation as perceived by the farmer, the greater the viability of the farm. An opposite trend was observed for the age of the farmer. Older farmers generally planned to soon cease farming or decrease herd size, whereas young farmers planned to increase the size of their herds. Implications of including these elements in conservation policies are discussed.

Use of ultrasound in the reproductive management of dairy cattle

The significant decrease in fertility observed in dairy cattle during the last few decades and increasing requirements by the farmers have made a regular control of reproduction indispensable to urgently identify and solve potential problems affecting reproductive efficiency. Traditionally, the main diagnostic methods used for reproductive control in cattle included rectal palpation, inspection of vaginal discharge and vaginoscopy. Since the 1990 s, the use of ultrasound (US) has become a common diagnostic method as a result of the new advances made in the development of US scans: smaller size, high level of autonomy, high image quality and accessible prices. Ultrasound improves accuracy in the diagnoses of stages of the oestrous cycle, ovarian and uterine pathologies, and pregnancy diagnosis. In addition, it facilitates the diagnosis of alterations during pregnancy (embryo mortality, foetal malformations, etc.) and helps determining foetal sex from day 55 of pregnancy.

Helium, neon and argon diffraction from Ru(0001)

We present an experimental and theoretical study of He, Ne and Ar diffraction from the Ru(0001) surface. Close-coupling calculations were performed to estimate the corrugation function and the potential well depth in the atom-surface interaction in all three cases. DFT (density functional theory) calculations, including van der Waals dispersion forces, were used to validate the close-coupling results and to further analyze the experimental results. Our DFT calculations indicate that, in the incident energy range 20-150 meV, anticorrugating effects are present in the case of He and Ar diffraction, whereas normal corrugation is observed with Ne beams.

Role of the non-canonical notch ligand delta-like protein 1 in hormone-producing cells of the adult male mouse pituitary

To better understand the role of the non-canonical Notch ligand delta-like protein 1 (DLK1), in hormone-producing cells, we studied the cell distribution and subcellular localisation of DLK1 in the pituitary of male adult 129/SvJ mice, and analysed the variations in the hormone-producing cells associated with the lack of this gene in Dlk1 knockout mice. The results obtained showed the presence of DLK1-immunoreactive (ir) cells in all hormone-producing cells of the anterior pituitary. Immunoelectron microscopy showed DLK1-ir in the rough endoplasmic reticulum and inside secretory vesicles, suggesting that DLK1 is released together with pituitary hormones. Moreover, we found that prolactin (PRL)-DLK1-ir cells are in intimate contact with follicle-stimulating hormone (FSH)-ir-DLK1-negative cells. In Dlk1 knockout mice, we detected a significantly lower number of gowth hormone (GH)-ir cells, a reduction in the FSH and PRL immunostaining intensity, and a significant decrease in FSH mRNA expression compared to wild-type mice. An increase in pituitary GH mRNA expression and serum leptin levels was also found. These findings provide evidence supporting several regulatory functions of DLK1 in the pituitary gland.

Role of dispersion forces in the structure of graphene monolayers on Ru surfaces

Elaborate density functional theory (DFT) calculations that include the effect of van der Waals (vdW) interactions have been carried out for graphene epitaxially grown on Ru(0001). The calculations predict a reduction of structural corrugation in the observed moiré pattern of about 25% (∼0.4 Å) with respect to DFT calculations without vdW corrections. The simulated STM topographies are close to the experimental ones in a wide range of bias voltage around the Fermi level.

Fetal gender determination by first-trimester ultrasound in dairy cows under routine herd management in Northwest Spain

Ultrasonography (US) provides detailed visualization of the fetus in early pregnancy in cows, thus allowing for fetal sex determination. The objective of this prospective observational study was to determine the feasibility and accuracy of a single US examination to diagnose fetal sex in dairy cattle under routine reproductive management conditions. For this purpose, 953 Holstein cows at 7-16 weeks of gestation were examined. Gender assignment was performed in 822 cows, while the genitalia could not be clearly visualized in 131 (13.7%) of the fetuses. After calving, it was verified that 99.3% of the diagnoses were accurate. Fetal sex was correctly determined by US in 99.5% of male fetuses and 98.8% of female fetuses. Fetal sex determination was less accurate when conducted before d 55 of gestation. Likewise, it was verified that fetal sex, cow age and ultrasonographic diagnosis section did not have a significant influence (P>0.05) on diagnostic accuracy. With respect to the plane used for diagnosis, the sagittal view was poorly used for early pregnancy diagnosis, whereas the longitudinal and cross-sectional planes were used most frequently. These results demonstrate that US can be routinely applied under farm conditions to accurately determine the fetal sex in cattle between days 51 and 111 of gestation without apparent influence of cow age, US scanning plane or fetal sex. Conversely, days of gestation affected the accuracy and feasibility of US gender determination, showing poorer results when the diagnosis was made before day 55 of gestation.

Peptidolytic Microbial Community of Methanogenic Reactors from two Modified Uasbs of Brewery Industries

We studied the peptide-degrading anaerobic communities of methanogenic reactors from two mesophilic full-scale modified upflow anaerobic sludge blanket (UASB) reactors treating brewery wastewater in Colombia. Most probable number (MPN) counts varied between 7.1 x 10(8) and 6.6 × 10(9) bacteria/g volatile suspended solids VSS (Methanogenic Reactor 1) and 7.2 × 10(6) and 6.4 × 10(7) bacteria/g (VSS) (Methanogenic Reactor 2). Metabolites detected in the highest positive MPN dilutions in both reactors were mostly acetate, propionate, isovalerate and, in some cases, negligible concentrations of butyrate. Using the highest positive dilutions of MPN counts, 50 dominant strains were isolated from both reactors, and 12 strains were selected for sequencing their 16S rRNA gene based on their phenotypic characteristics. The small-subunit rRNA gene sequences indicated that these strains were affiliated to the families Propionibacteriaceae, Clostridiaceae and Syntrophomonadaceae in the low G + C gram-positive group and Desulfovibrio spp. in the class δ-Proteobacteria. The main metabolites detected in the highest positive dilutions of MPN and the presence of Syntrophomonadaceae indicate the effect of the syntrophic associations on the bioconversion of these substrates in methanogenic reactors. Additionally, the potential utilization of external electron acceptors for the complete degradation of amino acids by Clostridium strains confirms the relevance of these acceptors in the transformation of peptides and amino acids in these systems.

Cutaneous manifestations in renal transplant recipients of Santiago, Chile

INTRODUCTION

Renal transplant recipients have a heightened risk of developing various cutaneous manifestations, such as skin infections, skin cancer, and secondary effects of immunosuppressive drugs. These manifestations differ depending on the evaluated population. The objective of this study was to describe the prevalence of cutaneous manifestations among renal transplant recipients in Chile between 1979 and 2008.

METHODS

Patients were recruited and then evaluated using a standardized questionnaire. Dermatologic physical examination was performed in every patient describing skin lesions, immunosuppressive drug effects, and malignant diseases. All suspicious lesions were biopsied for analysis. Every patient was queried for the development of skin cancer after his or her transplantation.

RESULTS

A total of 91 patients were enrolled; ages 10-67 years. Sixty percent of the patients presented with an infection at the initial evaluation. The most common infection was onychomycosis (58%) and verruca vulgaris (25%). In this study 58% of patients developed cutaneous side effects of immunosuppressive drugs. Among the evaluated patients, 16% showed premalignant or malignant manifestations on physical examination. The most frequent manifestations were actinic keratosis (17%), basal cell carcinoma (1%), and squamous cell carcinoma (1%). On a retrospective analysis, 12% of patients developed skin cancer after transplantation, 66% squamous cell carcinoma and 34% basal cell carcinoma, with a ratio of 1.9 to 1.

DISCUSSION

Cutaneous manifestations in renal transplant recipients are generally secondary to immunosuppression. These patients show a greater risk of having human papilloma virus (HPV) infections and nonmelanoma skin cancer. Periodic dermatologic evaluation of these patients should be performed to detect early lesions and modify risk factors.