Terrestrial-type planet formation: Comparing different types of initial conditions

To study the terrestrial-type planet formation during the post oligarchic growth, the initial distributions of planetary embryos and planetesimals used in N-body simulations play an important role. Most of these studies typically use ad hoc initial distributions based on theoretical and numerical studies. We analyze the formation of planetary systems without gas giants around solar-type stars focusing on the sensitivity of the results to the particular initial distributions of planetesimals and embryos. The formation of terrestrial planets in the habitable zone (HZ) and their final water contents are topics of interest. We developed two different sets of N-body simulations from the same protoplanetary disk. The first set assumes ad hoc initial distributions for embryos and planetesimals and the second set obtains these distributions from the results of a semi-analytical model which simulates the evolution of the gaseous phase of the disk. Both sets form planets in the HZ. Ad hoc initial conditions form planets in the HZ with masses from $0.66M_{\oplus}$ to $2.27M_{\oplus}$. More realistic initial conditions obtained from a semi-analytical model, form planets with masses between $1.18M_{\oplus}$ and $2.21M_{\oplus}$. Both sets form planets in the HZ with water contents between 4.5% and 39.48% by mass. Those planets with the highest water contents respect to those with the lowest, present differences regarding the sources of water supply. We suggest that the number of planets in the HZ is not sensitive to the particular initial distribution of embryos and planetesimals and thus, the results are globally similar between both sets. However, the main differences are associated to the accretion history of the planets in the HZ. These discrepancies have a direct impact in the accretion of water-rich material and in the physical characteristics of the resulting planets.Comment: Accepted for publication in Astronomy and Astrophysics, 13 pages, 9 figure

Chemical composition of Earth-like planets

Models of planet formation are mainly focused on the accretion and dynamical processes of the planets, neglecting their chemical composition. In this work, we calculate the condensation sequence of the different chemical elements for a low-mass protoplanetary disk around a solar-type star. We incorporate this sequence of chemical elements (refractory and volatile elements) in our semi-analytical model of planet formation which calculates the formation of a planetary system during its gaseous phase. The results of the semi-analytical model (final distributions of embryos and planetesimals) are used as initial conditions to develope N-body simulations that compute the post-oligarchic formation of terrestrial-type planets. The results of our simulations show that the chemical composition of the planets that remain in the habitable zone has similar characteristics to the chemical composition of the Earth. However, exist differences that can be associated to the dynamical environment in which they were formed.Comment: 3 pages, 4 figures - Accepted for publication in the Bolet\'in de la Asociaci\'on Argentina de Astronom\'ia, vol.5

A Robust Adaptive Hydraulic Power Generation System for Jet Engines

The paper presents an innovative hydraulic power generation system able to enhance performance, reliability and survivability of hydraulic systems used in military jet engines, as well as to allow a valuable power saving. This is obtained by a hydraulic power generation system architecture that uses variable pressure, smart control, emergency power source and suitable health management procedures. A key issue is to obtain all these functions while reducing to a minimum the number of additional components with respect to the conventional hydraulic power generation systems. The paper firstly presents the state-of-art of these systems and their critical issues, outlines the alternative solutions, and then describes architecture, characteristics and performance of the hydraulic power generation system that was eventually defined as a result of a research activity aimed at moving beyond the present state-of-art in this fiel

Epidemiology of histologically proven Glomerulonephritis in Africa: A systematic review and meta-analysis

Background and aim: Glomerulonephritis (GN) is a leading cause of end-stage renal disease (ESRD) in Africa. Data on epidemiology and outcomes of glomerular diseases from Africa is still limited. We conducted a systematic review on the epidemiology of histologically proven glomerular diseases in Africa between 1980 and 2014. Materials and methods We searched literature using PubMed, AfricaWide, the Cumulative Index to Nursing and Allied Health Literature on EBSCO Host, Scopus, African Journals online databases, and the African Index Medicus, for relevant studies. The review was conducted using standard methods and frameworks using only biopsy-confirmed data. RESULTS: Twenty four (24) studies comprising 12,093 reported biopsies from 13 countries were included in this analysis. The median number of biopsies per study was 127.0 (50-4436), most of the studies (70.0%) originated from North Africa and the number of performed kidney biopsies varied from 5.2 to 617 biopsies/year. Nephrotic syndrome was the commonest indication of renal biopsy. The frequency of reported primary pathologic patterns included, minimal change disease (MCD); 16.5% (95%CI: 11.2-22.6), focal segmental glomerulosclerosis (FSGS); 15.9% (11.3-21.1), mesangiocapillary GN (MCGN); 11.8% (9.2-14.6), crescentic GN; 2.0% (0.9-3.5) and IgA nephropathy 2.8% (1.3-4.9). Glomerular diseases related to hepatitis B and systemic lupus erythematosus had the highest prevalence among assessed secondary diseases: 8.4% (2.0-18.4) and 7.7% (4.5-11.7) respectively. There was no evidence of publication bias and regional differences were seen mostly for secondary GNs. CONCLUSIONS: Glomerular diseases remain poorly characterized in sub-Saharan Africa due to declining renal biopsy rates and consequent paucity of data on pathologic patterns of key renal diseases. Development of renal biopsy registries in Africa is likely to enable adequate characterization of the prevalence and patterns of glomerular diseases; this could have a positive impact on chronic kidney disease evaluation and treatment in the African continent since most glomerulopathies are amenable to treatment

Impact of the introduction of organised screening for cervical cancer in Turin, Italy: cancer incidence by screening history 1992–98

After an organised cervical screening programme was introduced in Turin in 1992, the age-adjusted cervical cancer incidence ratio in 1992–98 was 0.81 (95% confidence interval (CI) 0.59–1.09) for invited vs not invited women and 0.25 (95% CI 0.13–0.50) for attenders vs non attenders. An organised screening programme can further reduce cervical cancer incidence in an area where substantial spontaneous activity was previously present

Dietary patterns and risk of ductal carcinoma of the breast: A factor analysis in Uruguay

Breast cancer (BC) shows very high incidence rates in Uruguayan women. The present factor analysis of ductal carcinoma of the breast, the most frequent histological type of this malignancy both in Uruguay and in the World, was conducted at a prepaid hospital of Montevideo, Uruguay. We identified 111 cases with ductal BC and 222 controls with normal mammograms. A factor analysis was conducted using 39 food groups, allowing retention of six factors analyzed through logistic regression in order to obtain odds ratios (OR) associated with ductal BC. The low fat and non-alcoholic beverage patterns were inversely associated (OR=0.30 and OR=0.45, respectively) with risk. Conversely, the fatty cheese pattern was positively associated (OR=4.17) as well as the fried white meat (OR=2.28) and Western patterns (OR 2.13). Ductal BC shared similar dietary risk patterns as those identified by studies not discriminating between histologic type of breast cancer

Small non-coding RNA profiling in human biofluids and surrogate tissues from healthy individuals. Description of the diverse and most represented species

The role of non-coding RNAs in different biological processes and diseases is continuously expanding. Next-generation sequencing together with the parallel improvement of bioinformatics analyses allows the accurate detection and quantification of an increasing number of RNA species. With the aim of exploring new potential biomarkers for disease classification, a clear overview of the expression levels of common/unique small RNA species among different biospecimens is necessary. However, except for miRNAs in plasma, there are no substantial indications about the pattern of expression of various small RNAs in multiple specimens among healthy humans. By analysing small RNA-sequencing data from 243 samples, we have identified and compared the most abundantly and uniformly expressed miRNAs and non-miRNA species of comparable size with the library preparation in four different specimens (plasma exosomes, stool, urine, and cervical scrapes). Eleven miRNAs were commonly detected among all different specimens while 231 miRNAs were globally unique across them. Classification analysis using these miRNAs provided an accuracy of 99.6% to recognize the sample types. piRNAs and tRNAs were the most represented non-miRNA small RNAs detected in all specimen types that were analysed, particularly in urine samples. With the present data, the most uniformly expressed small RNAs in each sample type were also identified. A signature of small RNAs for each specimen could represent a reference gene set in validation studies by RT-qPCR. Overall, the data reported hereby provide an insight of the constitution of the human miRNome and of other small non-coding RNAs in various specimens of healthy individuals