1,914 research outputs found

    Analytical solution for the long- and short-range every-pair-interactions model

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    Many physical, biological, and social systems exhibit emergent properties that arise from the interactions between their components (cells). In this study, we systematically treat every-pair interactions (a) that exhibit power-law dependence on the Euclidean distance and (b) act in structures that can be characterized using fractal geometry. We analytically derive the mean interaction field of the cells and find that (i) in a long-range interaction regime, the mean interaction field increases following a power law with the size of the system, (ii) in a short-range interaction regime, the field saturates, and (iii) in the intermediate range it follows a logarithmic behaviour. To validate our analytical solution, we perform numerical simulations. In the case of short-range interactions, we observe that discreteness significantly impacts the continuum approximation used in the derivation, leading to incorrect asymptotic behaviour in this regime. To address this issue, we propose an expansion that substantially improves the accuracy of the analytical expression. Furthermore, our results motivate us to explore a framework for estimating the fractal dimension of unknown structures. This approach offers an alternative to established methods such as box-counting or sandbox methods. Overall, we believe that our analytical work will have broad applicability in systems where every-pair interactions play a crucial role. The insights gained from this study can contribute to a better understanding of various complex systems and facilitate more accurate modelling and analysis in a wide range of disciplines

    Biotehnološka proizvodnja i svojstva fruktoznog sirupa

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    In response to the growing demand for the consumption of natural, healthy and low-calorie food, a large number of so-called alternative sugars has emerged since the early 80s, among them fructose. This sugar is a ketohexose, known as D-fructose or levulose, and is considered the sweetest sugar found in nature. Currently, fructose is mostly produced through the acid hydrolysis of sucrose, or through the multi-enzymatic hydrolysis of starch. Processes involving specific enzymes like inulinases, acting on widely available fructose polysaccharides such as inulin, have been studied as alternatives to the current approaches, in order to reduce time, complexity and costs involved in this process. Fructose syrup is used worldwide, mainly because of its sweetening power and functional properties. The present work aims to provide an overview of the properties of fructose and of the present and envisaged production processes, within the scope of a biotechnological approach.Zbog sve većih zahtjeva potrošača za prirodnom, zdravom i niskokaloričnom hranom, već od ranih 1980-ih godina razvijen je veliki broj tzv. alternativnih šećera, među njima i fruktoza, ketoheksoza, poznata kao D-fruktoza ili levuloza, koja je najslađi šećer u prirodi. Trenutačno se proizvodi najčešće kiselinskom hidrolizom saharoze ili enzimskom hidrolizom škroba. Da bi se dobio što brži, jednostavniji i jeftiniji postupak, istraženi su procesi u kojima se primjenjuju specifični enzimi poput inulinaza, što djeluju na razne fruktozne polisaharide (npr. inulin). Fruktozni se sirup koristi u cijelom svijetu uglavnom zbog svoje slatkoće i funkcionalnih svojstava. Svrha je ovoga rada prikazati postupke biotehnološke proizvodnje fruktoze te opisati njezina svojstva

    Supplement levels and functional oils to replace virginiamycin for young bulls during early dry season on grasslands and finishing phase in feedlot systems

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    Aim of study: To assess the effects of replacing virginiamycin (VM) by functional oils (FO) from castor beans and cashew nut on beef cattle system during the early dry season (Experiment I) and during the finishing phase were evaluated the historical effect, keeping the treatments and methods intact (Experiment II).Area of study: These experiments were conducted at the Forage Crops and Grasslands section of São Paulo State University, “Julio de Mesquita Filho” (Unesp–Jaboticabal, São Paulo, Brazil).Material and methods: Two supplementation levels combined with two additives (four treatments in total) were evaluated: LSVM, low supplementation (0.3% body weight [BW]) with VM; LSFO, low supplementation (0.3% BW) with FO, HSVM, high supplementation (0.6% BW) with VM, and HSFO, high supplementation (0.6% BW) with FO. In both experiments, the experimental design was completely randomized with a 2 × 2 factorial arrangement (supplementation levels × additives).Main results: In Exp. I, the additive effect of VM provided greater average daily gain (ADG, p=0.02), higher supplementation level resulted in higher ADG (p=0.04) and the greatest crude protein apparent digestibility (p=0.002). However, no effects were observed between supplementation levels, additives, and interactions (p≥0.11) on voluntary intake and ruminal parameters. In Exp. II, LSVM treatment resulted in lower dry matter intake (p=0.04). Animals maintained on LSFO during the early dry season exhibited lower carcass yield (p=0.004).Research highlights: FO can be used to replace VM in beef cattle diet during the finishing phase in the feedlot without altering animal performance

    Stellar Population Properties of ETGs in Compact Groups of Galaxies

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    We present results on the study of the stellar population in Early-Type galaxies (ETGs) belonging to 151 Compact Groups (CGs). We also selected a field sample composed of 846 ETGs to investigate environmental effects on galaxy evolution. We find that the dependences of mean stellar ages, [Z/H] and [α\alpha/Fe] on central stellar velocity dispersion are similar, regardless where the ETG resides, CGs or field. When compared to the sample of centrals and satellites from the literature, we find that ETGs in GCs behave similarly to centrals, especially those embedded in low-mass haloes (Mh<1012.5MM_{h} < 10^ {12.5}M_{\odot}). Except for the low-mass limit, where field galaxies present a Starforming signature, not seen in CGs, the ionization agent of the gas in CG and field galaxies seem to be similar and due to hot, evolved low-mass stars. However, field ETGs present an excess of Hα\alpha emission relative to ETGs in CGs. Additionally, we performed a dynamical analysis, which shows that CGs present a bimodality in the group velocity dispersion distribution - a high and low-σ\sigma mode. Our results indicate that high-σ\sigma groups have a smaller fraction of spirals, shorter crossing times, and a more luminous population of galaxies than the low σ\sigma groups. It is important to emphasize that our findings point to a small environmental impact on galaxies located in CGs. The only evidence we find is the change in gas content, suggesting environmentally-driven gas loss.Comment: 21 pages, 18 Figure

    A polyalanine peptide derived from polar fish with anti-infectious activities

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    Due to the growing concern about antibiotic-resistant microbial infections, increasing support has been given to new drug discovery programs. A promising alternative to counter bacterial infections includes the antimicrobial peptides (AMPs), which have emerged as model molecules for rational design strategies. Here we focused on the study of Pa-MAP 1.9, a rationally designed AMP derived from the polar fish Pleuronectes americanus. Pa-MAP 1.9 was active against Gram-negative planktonic bacteria and biofilms, without being cytotoxic to mammalian cells. By using AFM, leakage assays, CD spectroscopy and in silico tools, we found that Pa-MAP 1.9 may be acting both on intracellular targets and on the bacterial surface, also being more efficient at interacting with anionic LUVs mimicking Gram-negative bacterial surface, where this peptide adopts α-helical conformations, than cholesterol-enriched LUVs mimicking mammalian cells. Thus, as bacteria present varied physiological features that favor antibiotic-resistance, Pa-MAP 1.9 could be a promising candidate in the development of tools against infections caused by pathogenic bacteria.National Institute of Allergy and Infectious Diseases (U.S.) (R21AI098701

    An environmental dependence of the physical and structural properties in the Hydra cluster galaxies

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    The nearby Hydra cluster (∼50 Mpc) is an ideal laboratory to understand, in detail, the influence of the environment on the morphology and quenching of galaxies in dense environments. We study the Hydra cluster galaxies in the inner regions (1R200) of the cluster using data from the Southern Photometric Local Universe Survey, which uses 12 narrow and broad-band filters in the visible region of the spectrum. We analyse structural (Sérsic index, effective radius) and physical (colours, stellar masses, and star formation rates) properties. Based on this analysis, we find that ∼88 per cent of the Hydra cluster galaxies are quenched. Using the Dressler–Schectman test approach, we also find that the cluster shows possible substructures. Our analysis of the phase-space diagram together with density-based spatial clustering algorithm indicates that Hydra shows an additional substructure that appears to be in front of the cluster centre, which is still falling into it. Our results, thus, suggest that the Hydra cluster might not be relaxed. We analyse the median Sérsic index as a function of wavelength and find that for red [(u − r) ≥2.3] and early-type galaxies it displays a slight increase towards redder filters (13 and 18 per cent, for red and early type, respectively), whereas for blue + green [(u − r)<2.3] galaxies it remains constant. Late-type galaxies show a small decrease of the median Sérsic index towards redder filters. Also, the Sérsic index of galaxies, and thus their structural properties, do not significantly vary as a function of clustercentric distance and density within the cluster; and this is the case regardless of the filter.CL-D acknowledges scholarship from CONICYT-PFCHA/Doctorado Nacional/2019-21191938. CL-D and AM acknowledge support from FONDECYT Regular grant 1181797. CL-D acknowledges also the support given by the ‘Vicerrectoría de Investigacion de la Universidad de La Serena’ program ‘Apoyo al fortalecimiento de grupos de investigacion’. CL-D and AC acknowledges to Steven Bamford and Boris Haeussler with the MegaMorph project. CL-D and DP acknowledge support from fellowship ‘Becas Doctorales Institucionales ULS’, granted by the ‘Vicerrectoría de Investigacion y Postgrado de la Universidad de La Serena’. AM and DP acknowledge funding from the Max Planck Society through a ‘Partner Group’ grant. DP acknowledges support from FONDECYT Regular grant 1181264. This work has used the computing facilities of the Laboratory of Astroinformatics (Instituto de Astronomia, Geofísica e Ciencias Atmosféricas, Departamento de Astronomia/USP, NAT/Unicsul), whose purchase was made possible by FAPESP (grant 2009/54006-4) and the INCT-A. YJ acknowledges financial support from CONICYT PAI (Concurso Nacional de Inserción en la Academia 2017) No. 79170132 and FONDECYT Iniciación 2018 No. 11180558. LS thanks the FAPESP scholarship grant 2016/21664-2. AAC acknowledges support from FAPERJ (grant E26/203.186/2016), CNPq (grants 304971/2016-2 and 401669/2016-5), and the Universidad de Alicante (contract UATALENTO18-02). AMB thanks the FAPESP scholarship grant 2014/11806-9. RA acknowedges support from ANID FONDECYT Regular grant 1202007

    Acute cardiometabolic effects of brief active breaks in sitting for patients with rheumatoid arthritis

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    Exercise is a treatment in rheumatoid arthritis, but participation in moderate-to-vigorous exercise is challenging for some patients. Light-intensity breaks in sitting could be a promising alternative. We compared the acute effects of active breaks in sitting with those of moderate-to-vigorous exercise on cardiometabolic risk markers in patients with rheumatoid arthritis. In a crossover fashion, 15 women with rheumatoid arthritis underwent three 8-h experimental conditions: prolonged sitting (SIT), 30-min bout of moderate-to-vigorous exercise followed by prolonged sitting (EX), and 3-min bouts of light-intensity walking every 30 min of sitting (BR). Postprandial glucose, insulin, c-peptide, triglycerides, cytokines, lipid classes/subclasses (lipidomics), and blood pressure responses were assessed. Muscle biopsies were collected following each session to assess targeted proteins/genes. Glucose [−28% in area under the curve (AUC), P = 0.036], insulin (−28% in AUC, P = 0.016), and c-peptide (−27% in AUC, P = 0.006) postprandial responses were attenuated in BR versus SIT, whereas only c-peptide was lower in EX versus SIT (−20% in AUC, P = 0.002). IL-1β decreased during BR, but increased during EX and SIT (P = 0.027 and P = 0.085, respectively). IL-1ra was increased during EX versus BR (P = 0.002). TNF-α concentrations decreased during BR versus EX (P = 0.022). EX, but not BR, reduced systolic blood pressure (P = 0.013). Lipidomic analysis showed that 7 of 36 lipid classes/subclasses were significantly different between conditions, with greater changes being observed in EX. No differences were observed for protein/gene expression. Brief active breaks in sitting can offset markers of cardiometabolic disturbance, which may be particularly useful for patients who may find it difficult to adhere to exercise. NEW & NOTEWORTHY Exercise is a treatment in rheumatoid arthritis but is challenging for some patients. Light-intensity breaks in sitting could be a promising alternative. Our findings show beneficial, but differential, cardiometabolic effects of active breaks in sitting and exercise in patients with rheumatoid arthritis. Breaks in sitting mainly improved glycemic and inflammatory markers, whereas exercise improved lipidomic and hypotensive responses. Breaks in sitting show promise in offsetting aspects of cardiometabolic disturbance associated with prolonged sitting in rheumatoid arthritis
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