Random walk on random walks: low densities

We consider a random walker in a dynamic random environment given by a system of independent simple symmetric random walks. We obtain ballisticity results under two types of perturbations: low particle density, and strong local drift on particles. Surprisingly, the random walker may behave very differently depending on whether the underlying environment particles perform lazy or non-lazy random walks, which is related to a notion of permeability of the system. We also provide a strong law of large numbers, a functional central limit theorem and large deviation bounds under an ellipticity condition.Comment: 28 page

THE IMMUNOLOGY OF EXPERIMENTAL CHAGAS' DISEASE : III. REJECTION OF ALLOGENEIC HEART CELLS IN VITRO

Experiments that consisted of incubation of Trypanosoma cruzi-sensitized lymphocytes derived from chronically infected rabbits and from rabbits repeatedly immunized with a small particle or membrane fraction derived from homogenates of T. cruzi forms, showed destruction of allogeneic, parasitized and nonparasitized heart cells in vitro. Mononuclear cells collected from peripheral blood were incubated for 1 h at 37°C to isolate the lymphocytes. Following incubation, over 99% of the cells in the supernate were lymphocytes, which were utilized in these experiments. At the start of these experiments, 70–80% of the sensitized lymphocytes were unattached, small and round, with sparse filipodia. In the ensuing hours, marked heart cell destruction, similar to that seen in an active lesion when lymphocytes invade heart tissue, were observed. After 18 h incubation, about 65–70% of the lymphocytes were attached, larger, and rough surfaced. Inhibition of monocyte migration tests, each in the presence of the antigens of subcellular fractions of T. cruzi organisms and of allogeneic heart myofibers, indicated the presence of a cross-reacting antigen common to both the parasite and the heart in the small particle or membrane fractions. The particulate antigens of the 30,000 g, 35-min fraction of heart muscle gave rise to inhibition of monocyte migration as did the counterpart fraction derived from T. cruzi organisms. The destruction of nonparasitized target heart cells by T. cruzi-sensitized lymphocytes is an in vitro model of the chronic myocarditis of Chagas' disease, and the recognition of cross-reactive antigens of the host cell by T. cruzi-sensitized lymphocytes is believed to be the pathogenic basis for subsequent tissue injury in the chronic phase of this disease

Thermal comfort evaluation of an operating room through CFD methodology

Different studies have been evidencing that the surgeon, working with a high metabolic rate, feels uncomfortable after a time. This enforces the study of indoor thermal conditions in health care facilities. The main objective of the present work is the evaluation of the thermal comfort sensation experienced by surgeons and nurses inside a Portuguese orthopaedic surgical room, using the PMV index. Through CFD tools and a post-processing routine, it was obtained the PMV index in each domain node, in opposite to the typical use of average climate values. The use of average ventilation values, to calculate the index, does not provide a correct and enough descriptive evaluation of the surgical room thermal environment. It is noticeable that surgeons and nurses feel different thermal sensations in the same surgical room. For the studied case, the surgeon feels the room environment hotter than the nurse. The nurses feel a slightly cold sensation under the air supply diffuser and a neutral zone is located in the air stagnation zones close to the walls. As expected for both cases, lamps provide an uncomfortable sensation. The clothing used by both classes, as well as the ventilation conditions, shall be revised accordingly to the amount of persons in the room and the type of activity performed

Fractionation of the major whey proteins and isolation of β-Lactoglobulin variants by anion exchange chromatography

A method for the separation and fractionation of the major whey proteins from a whey protein concentrate (WPC80) by anion-exchange chromatography coupled to a Fast Protein Liquid Chromatography (FPLC) system is proposed. The method is based on the use of an ionic column (Mono Q) and a salt gradient elution by increasing the ionic strength of the elution buffer (Tris–HCl 20 mM plus 0 to 1 M NaCl). The proposed method was found to be suitable to fractionate the major whey proteins from the WPC80 in different fractions, namely one fraction containing all the a-Lactalbumin and immunoglobulins; another fraction containing all the bovine serum albumin; and two distinct fractions each containing a different variant of b-Lactoglobulin. A 60.5% (w/w) recovery of the two main b-Lactoglobulin variants was obtained

Influence of cardiorespiratory fitness and parental lifestyle on adolescents' abdominal obesity

The aims of this study were (1) to analyse the influence of cardiorespiratory fitness (CRF) and parental overweight status (POS) and socioeconomic status (SES) on abdominal obesity. This study was comprised of 779 adolescents (12-18 years). Waist-height ratio (WHtR), 20 m shuttle-run test to ascertain CRF, POS according to World Health Organization recommendations and SES of parents using level of education were analysed. Using WHtR, the prevalence of abdominal obesity was 21.3% (23.5% girls and 17.9% boys; p = 0.062). Regardless of gender, participants who belonged to the WHtR risk group had significantly (p ≤ 0.05) lower CRF scores than the WHtR non-risk group; 84.4% of girls who belonged to the WHtR risk group had one or two overweight parents (p ≤ 0.05). Boys with low CRF (OR: 6.43; CI: 3.33-12.39) were more likely to belong to the WHtR risk group compared with their lean peers. Girls with low CRF (OR: 1.78; CI: 1.14-2.78) and with at least one overweight parent (OR: 2.50; CI: 1.07-5.85) or two overweight parents (OR: 4.90; CI: 2.08-11.54) were associated with the risk of abdominal obesity. This study highlights the influence of adolescents' family on abdominal obesity, especially in girls. Further, the data suggested that low CRF was a strong predictor of risk values of abdominal obesity in adolescence

Random walk on random walks: Low densities

We consider a random walker in a dynamic random environment given by a system of independent simple symmetric random walks. We obtain ballisticity results under two types of perturbations: low particle density, and strong local drift on particles. Surprisingly, the random walker may behave very differently depending on whether the underlying environment particles perform lazy or non-lazy random walks, which is related to a notion of permeability of the system. We also provide a strong law of large numbers, a functional central limit theorem and large deviation bounds under an ellipticity condition

Hargreaves and other reduced-set methods for calculating evapotranspiration

This edition of Evapotranspiration - Remote Sensing and Modeling contains 23 chapters related to the modeling and simulation of evapotranspiration (ET) and remote sensing-based energy balance determination of ET. These areas are at the forefront of technologies that quantify the highly spatial ET from the Earth's surface. The topics describe mechanics of ET simulation from partially vegetated surfaces and stomatal conductance behavior of natural and agricultural ecosystems. Estimation methods that use weather based methods, soil water balance, the Complementary Relationship, the Hargreaves and other temperature-radiation based methods, and Fuzzy-Probabilistic calculations are described. A critical review describes methods used in hydrological models. Applications describe ET patterns in alpine catchments, under water shortage, for irrigated systems, under climate change, and for grasslands and pastures. Remote sensing based approaches include Landsat and MODIS satellite-based energy balance, and the common process models SEBAL, METRIC and S-SEBS. Recommended guidelines for applying operational satellite-based energy balance models and for overcoming common challenges are made

Analysis of the profile of volatile organic compounds in Chlorella vulgaris

It is known that the incorporation of microalgae into foodstuffs enables to modify the overall flavor leading to desirable or undesirable organoleptic properties. Nevertheless, few were the studies conducted focusing on the analysis of the profile of volatile organic compounds (VOCs) produced by microalgae, which are the main compounds responsible for the aroma perception. The aim of this study was to analyze the VOCs profile of Chlorella vulgaris powder by gas chromatography coupled with mass spectrometry (GC-MS). Different techniques were used for the extraction of the VOCs, prior to the chromatographic analysis: 1) solid-phase microextraction (SPME), and 2) ultrasound-assisted liquid extraction (UALE) using five different solvents. For the SPME analysis, 0.5 g of C. vulgaris was exposed to a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber and was desorbed for 5 min into GC-MS. For the UALE, 2 g of sample was placed in five different solvents for extraction (chloroform, dichloromethane, hexane, ethyl acetate and acetone). For both SPME and UALE the GC-MS analysis was performed on Stabilwax (SW) and RXI-5 columns. The results showed very different profiles of VOCs between columns and techniques of extractions. In the analysis with the SW column no compounds were detected in acetone, hexane and ethyl acetate and only a few were present with the chloroform (39 VOCs) and dichloromethane (15 VOCs) extraction when compared to SPME (75 VOCs). In the RXI-5 analysis, a reduced number of compounds was identified when comparing with SW in SPME (39 and 75 VOCs, respectively), and in UALE, ethyl acetate was the only solvent with any retention of VOCs that could be detected with this column, having chloroform, dichloromethane, acetone and hexane, 10, 10, 5, and 8 VOCs respectively. In SPME, the main chemical classes of identified VOCs were, alcohols and hydrocarbons. In UALLE, the VOCs profile was more balanced with alcohols, aldehydes, carboxy group, ketones and hydrocarbons. Only with hexane it was possible to find aromatic groups. Compounds such as hexanal, tetradecane, and 3-methylbutanal were found in SPME as reported in literature, although 3-methylbutanal was only present for SW. In conclusion, SPME run in a SW column showed more VOCs retention and seems to be more appropriate to enable aroma prediction in C. vulgaris-based foodstuff.Portuguese Foundation for Science and Technology (FCT) - 2021.05734.BDinfo:eu-repo/semantics/publishedVersio