On Y-Linked Genes and Bisexual Branching Processes

2000 Mathematics Subject Classification: 60J80.In this paper we survey the results concerning the extinction problem for a two-allele Y-linked gene in a two-sex monogamic population, with a preference of females for males carrying one of the two alleles of the gene. First we give the mathematical definition of the Y-linked bisexual branching process to model this situation and study some of its relevant properties. Then, we research the extinction of the population and also the survival of each genotype depending on the behaviour of the other genotype. Finally, we simulate the evolution of the population and conjecture its long term behaviour, for some critical situations.This research was supported by the Ministerio de Educacion y Ciencia and the FEDER through the Plan Nacional de Investigaci´on Cient´ıfica, Desarrollo e Innovaci´on Tecnologica, grant MTM2006-08891

Is spark plasma sintering suitable for the densification of continuous carbon fibre - UHTCMCs?

For the first time we show that spark plasma sintering can efficiently replace hot pressing for the densification of UHTCMCs, in the present case ZrB2/SiC composites reinforced with continuous carbon fibres. To this purpose, the same materials were first produced by hot pressing as baseline samples and then by spark plasma sintering (SPS) to compare microstructure and basic mechanical properties. A special emphasis was given to the study of interfaces, in case of both coated and uncoated carbon fibres. SPS allowed for faster sintering but required an adjustment of the temperature to avoid fibre degradation compared to hot pressing. With similar porosity levels, we observed a slight decrease of flexural strength (300 vs 470 MPa), and an improvement of fracture toughness (15 vs 10 MPa√m) for SPSed samples. SPS was proved to be an effective method for the consolidation of continuous fibre reinforced UHTC composites

Peaks in the Cosmic Microwave Background: flat versus open models

We present properties of the peaks (maxima) of the CMB anisotropies expected in flat and open CDM models. We obtain analytical expressions of several topological descriptors: mean number of maxima and the probability distribution of the gaussian curvature and the eccentricity of the peaks. These quantities are calculated as functions of the radiation power spectrum, assuming a gaussian distribution of temperature anisotropies. We present results for angular resolutions ranging from 5' to 20' (antenna FWHM), scales that are relevant for the MAP and COBRAS/SAMBA space missions and the ground-based interferometer experiments. Our analysis also includes the effects of noise. We find that the number of peaks can discriminate between standard CDM models, and that the gaussian curvature distribution provides a useful test for these various models, whereas the eccentricity distribution can not distinguish between them.Comment: 13 pages latex file using aasms4.sty + 3 tables + 2 postscript figures, to appear in ApJ (March 1997

Distribution of eosinophils in the gastrointestinal tract of children with no organic disease

Background This study aimed to assess the eosinophil (eos) density of the mucosa of the gastrointestinal (GI) tract in children undergoing endoscopic procedures following an extensive workup, without diagnosis of an organic disease. Methods Biopsies from GI endoscopies performed at 3 major children’s hospitals (Athens, Madrid and Rome), between January 2012 and June 2018, were evaluated by a single pathologist in each center. Peak eos counts were expressed /high power field and /mm2. Other histological abnormalities were also reported. Results A total of 111 children (median age 11 years; 48 boys) underwent upper endoscopy (333 biopsies), while 44 (median age 12; 25 boys) underwent ileocolonoscopy (262 biopsies). The median (interquartile range) eos/mm2 were as follows: esophagus 0 (0-0); stomach 0 (0-3); duodenum 22 (13-29); ileum 29 (19-46); cecum 39 (25-71); ascending colon 24 (20-41); transverse colon 27 (21-57); descending colon 21 (13-27); sigmoid colon 22 (13-30); and rectum 10 (6-22). Geographical variations in GI tissue eos counts were found amongst the participating centers, but the causative factors need further evaluation. Functional GI disorders according to the Rome IV criteria were diagnosed in 73 children (37 boys, median age 13 years). No differences were found between children with or without functional GI disorder diagnosis, with regard to eos density in the GI tract. Conclusion The reported peak counts of GI tissue eos in children with no organic diseases provide normative values that may be useful in the evaluation of children with GI symptoms suggestive of eosinophilic GI disorders

Innovating Interdisciplinarity in Higher Education: Exploring the Impact of a Grassroots Community of Practice

Skills in interdisciplinary collaboration are required to address many complex problems facing society. As such, interdisciplinarity is a critical competency for students to develop. However, teachers’ effectiveness in teaching interdisciplinarity is often hindered by silo structures within university faculties. To address this in the Experts in Teamwork (EiT) programme, a MSc in a Norwegian university that develops students’ interdisciplinary teamwork skills through projects that address real-world challenges, a community of practice (CoP) evolved among teachers from different EiT classes. Over 20 months, CoP members participated in digital and in-person discussions, lecture exchanges, student and professional conferences, and co-evaluation of student work, with an aim of better understanding interdisciplinarity and approaches for teaching it to students. The success of the CoP in achieving these aims was evaluated through a series of focus groups consisting of members of the CoP. The CoP achieved some success in fostering pedagogical conversations that were transformative for participants’ understanding of interdisciplinarity in their practice. Participants reported that CoP participation influenced their interactions with students, ultimately helping students to develop a better understanding of interdisciplinarity. However, participants reported limitations in the CoP as a professional development resource, citing its newness and the required time commitment. Participants felt that these issues could be addressed via greater institutional support

Production performance, nutrient digestibility, and milk composition of dairy ewes supplemented with crushed sunflower seeds and sunflower seed silage in corn silage-based diets

This study determined production performance, nutrient digestibility, and milk composition of dairy ewes supplemented with crushed sunflower seeds (Helianthus annuus) and sunflower seed silage in corn silage-based diets. Six ewes were grouped in a double 3 × 3 Latin square design with three periods of 21 days. All treatments were based on ad libitum corn silage. Control diet was based on alfalfa hay (333 g/kg DM), sorghum grain (253 g/kg DM), triticale grain (200 g/kg DM), soybean meal (167 g /kg DM), and vitamin and mineral premix (47 g/kg DM). Sunflower seeds (SF) and sunflower seed silage (SFS) treatments consisted of alfalfa hay (333 g/kg DM), sorghum grain (267 g/kg DM), triticale grain (100 g/kg DM), soybean meal (167 g /kg DM), SF or SFS (87 g/kg DM) and vitamin and mineral premix (47 g/kg DM). Compared to control, SF and SFS increased intake and digestibility of fiber components, such as neutral detergent fiber (NDF) and acid detergent fiber (ADF). Body weight, nitrogen balance, milk yield, milk fat yield, milk protein yield, lactose yield and milk urea N were similar between treatments. Overall, results demonstrated that crushed sunflower seeds and ensiled seeds do not change significantly productive parameters of dairy sheep

A system of three transiting super-Earths in a cool dwarf star

We present the detection of three super-Earths transiting the cool star LP415-17, monitored by K2 mission in its 13th campaign. High resolution spectra obtained with HARPS-N/TNG showed that the star is a mid-late K dwarf. Using spectral synthesis models we infer its effective temperature, surface gravity and metallicity and subse- quently determined from evolutionary models a stellar radius of 0.58 R Sun. The planets have radii of 1.8, 2.6 and 1.9 R Earth and orbital periods of 6.34, 13.85 and 40.72 days. High resolution images discard any significant contamination by an intervening star in the line of sight. The orbit of the furthest planet has radius of 0.18 AU, close to the inner edge of the habitable zone. The system is suitable to improve our understanding of formation and dynamical evolution of super-Earth systems in the rocky - gaseous threshold, their atmospheres, internal structure, composition and interactions with host stars.Comment: Accepted for publication in MNRAS Letter