34 research outputs found

    Effects of Defoliation Frequency on Foraging Selective Behaviour in Pasture with Paspalum Dilatatum

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    The objective was to assess defoliation effects exerted by sheep grazing on a pasture composed by falaris and dallisgrass, at two phenological stages during spring and summer. A sown pasture of Phalaris aquatica and Paspalum dilatatum were grazed at two phenological stages: stage I (SI), with no more than 5% of reproductive tillers, and stage II (SII), with at least 70% of reproductive tillers. Tillers of both grass species were marked with plastic colour rings along two transects in each plot. Phenological stage of tillers, and the number, age and length of each leaf per tiller were registered. Tiller defoliation rates (TDR), Leaf defoliation rates (LDR) of young and old leaves and Defoliated tiller percent (DTP) were estimated for both species. The results obtained demonstrated that selective forage behaviour of grazing sheep showed the existence of mechanisms towards maximum forage consumption

    Analysis of Some Farm Driving Variables and Its Relation with Milk Production in a Pastoral Dairy Farm of Buenos Aires, Argentina

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    The quantity of milk solids produced determines a dairy farm income and contributes to its profit. Total pasture production, forage quality and herd consumption are factors to be managed in this production system. The outcomes of two years were analyzed. Primary production showed its dependence on climatic conditions and use of technological inputs. Forage quality was promoted through interseeding legumes, applying fertilizer and maintaining the pasture young and leafy. Total forage removed by the herd was similar in both years although pasture production decreased. It was possible to cope with seasonal variations in forage production, by varying the grazing pressure and this allowed an increase in daily herd milk production and annual fat production per hectare. Changes in milk production per cow was not related to changes in stocking rate, however, although the nutritive value of the pasture was improved during the second period, daily milk production and forage consumption per animal decreased when grazing pressure increased. The relation between total milk produced and total dry matter consumed in both periods were similar

    Psychometric network analysis of the Patient Health Questionnaire-4 (PHQ-4) in Paraguayan general population

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    Background: Depression and anxiety are two of the most prevalent and disabling mental disorders worldwide, both in the general population and in outpatient clinical settings. Objective: This study aimed to analyze the psychometric properties of the Patient Health Questionnaire-4 (PHQ-4) based on network analysis metrics. Methods: A total of 911 Paraguayans (23.71% women and 76.29% men; mean age 31.25 years, SD = 10.63), selected by non-probabilistic convenience sampling, participated in the study. Network analysis was used to evaluate the internal structure, reliability, and measurement invariance between men and women. Results: The results revealed that the PHQ-4 is a unidimensional measure through Exploratory Graph Analysis (EGA). Reliability, through structural consistency, identified that 100% of the time, only a single dimension was obtained, and all items remained stable, as they were always replicated within the empirical dimension. The unidimensional structure has shown evidence of configural invariance; therefore, the network structure functioned equally among the different sex groups. Conclusion: The PHQ-4 presented optimal preliminary evidence of validity based on its internal structure, reliability, and invariance between sexes. Therefore, it may be useful as an accurate and brief measure of anxiety and depressive symptoms in the Paraguayan context

    VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

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    VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

    Sensitization of cervix cancer cells to Adriamycin by Pentoxifylline induces an increase in apoptosis and decrease senescence

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    <p>Abstract</p> <p>Background</p> <p>Chemotherapeutic drugs like Adriamycin (ADR) induces apoptosis or senescence in cancer cells but these cells often develop resistance and generate responses of short duration or complete failure. The methylxantine drug Pentoxifylline (PTX) used routinely in the clinics setting for circulatory diseases has been recently described to have antitumor properties. We evaluated whether pretreatment with PTX modifies apoptosis and senescence induced by ADR in cervix cancer cells.</p> <p>Methods</p> <p>HeLa (HPV 18+), SiHa (HPV 16+) cervix cancer cells and non-tumorigenic immortalized HaCaT cells (control) were treated with PTX, ADR or PTX + ADR. The cellular toxicity of PTX and survival fraction were determinated by WST-1 and clonogenic assay respectively. Apoptosis, caspase activation and ADR efflux rate were measured by flow cytometry, senescence by microscopy. IκBα and DNA fragmentation were determinated by ELISA. Proapoptotic, antiapoptotic and senescence genes, as well as HPV-E6/E7 mRNA expression, were detected by time real RT-PCR. p53 protein levels were assayed by Western blot.</p> <p>Results</p> <p>PTX is toxic (WST-1), affects survival (clonogenic assay) and induces apoptosis in cervix cancer cells. Additionally, the combination of this drug with ADR diminished the survival fraction and significantly increased apoptosis of HeLa and SiHa cervix cancer cells. Treatments were less effective in HaCaT cells. We found caspase participation in the induction of apoptosis by PTX, ADR or its combination. Surprisingly, in spite of the antitumor activity displayed by PTX, our results indicate that methylxantine, <it>per se </it>does not induce senescence; however it inhibits senescence induced by ADR and at the same time increases apoptosis. PTX elevates IκBα levels. Such sensitization is achieved through the up-regulation of proapoptotic factors such as <it>caspase </it>and <it>bcl </it>family gene expression. PTX and PTX + ADR also decrease E6 and E7 expression in SiHa cells, but not in HeLa cells. p53 was detected only in SiHa cells treated with ADR.</p> <p>Conclusion</p> <p>PTX is a good inducer of apoptosis but does not induce senescence. Furthermore, PTX reduced the ADR-induced senescence and increased apoptosis in cervix cancer cells.</p

    Fear of monkeypox and intention to vaccinate against monkeypox: a network analysis

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    Introduction: The presence of fear of an infectious disease triggers psychological factors associated with perceived behavioral control over vaccination acceptance, subjective norms of vaccination acceptance, attitudes toward vaccination acceptance, and perceived infectiousness from disease. Objective: The study evaluated how symptoms of fear of Monkeypox specifically relate to intention to be vaccinated against Monkeypox in a sample of 506 Peruvian individuals with a mean age of 27.11 years (SD = 9.77). Methods: Participants responded to the Monkeypox Fear Scale (MFS) and a single item of Intention to be vaccinated against Monkeypox. Using network analysis, central fear symptoms and associations between symptoms and intention to vaccinate were identified. Results: The results suggest that the node with the highest centrality was item 5 of the MFS. Regarding the connection between the intention to be vaccinated and the MFS items, a direct relationship was observed with item 1 and an inverse relationship with item 6. In addition, the relationship between these MFS items and intention to vaccinate is higher in men compared to women. While it would be expected that a greater presence of symptoms of fear of Monkeypox could lead people to have a greater intention to be vaccinated against the disease, the results could lead other researchers to generate evidence to explain this relationship in other Latin American countries. Discussion:  The evidence is useful for developing policies that favor vaccination against Monkeypox in Peru and other Latin American countries

    A Contribution of the HAWC Observatory to the TeV era in the High Energy Gamma-Ray Astrophysics: The case of the TeV-Halos

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    We present a short overview of the TeV-Halos objects as a discovery and a relevant contribution of the High Altitude Water \v{C}erenkov (HAWC) observatory to TeV astrophysics. We discuss history, discovery, knowledge, and the next step through a new and more detailed analysis than the original study in 2017. TeV-Halos will contribute to resolving the problem of the local positron excess observed on the Earth. To clarify the latter, understanding the diffusion process is mandatory.Comment: Work presented in the 21st International Symposium on Very High Energy Cosmic Ray Interactions(ISVHECRI 2022) as part of the Ph. D. Thesis of Ramiro Torres-Escobedo (SJTU, Shanghai, China). Accepted for publication in SciPost Physics Proceedings (ISSN 2666-4003). 11 pages, 3 Figures. Short overview of HAWC and TeV Halos objects until 202

    The High-Altitude Water Cherenkov (HAWC) Observatory in M\'exico: The Primary Detector

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    The High-Altitude Water Cherenkov (HAWC) observatory is a second-generation continuously operated, wide field-of-view, TeV gamma-ray observatory. The HAWC observatory and its analysis techniques build on experience of the Milagro experiment in using ground-based water Cherenkov detectors for gamma-ray astronomy. HAWC is located on the Sierra Negra volcano in M\'exico at an elevation of 4100 meters above sea level. The completed HAWC observatory principal detector (HAWC) consists of 300 closely spaced water Cherenkov detectors, each equipped with four photomultiplier tubes to provide timing and charge information to reconstruct the extensive air shower energy and arrival direction. The HAWC observatory has been optimized to observe transient and steady emission from sources of gamma rays within an energy range from several hundred GeV to several hundred TeV. However, most of the air showers detected are initiated by cosmic rays, allowing studies of cosmic rays also to be performed. This paper describes the characteristics of the HAWC main array and its hardware.Comment: Accepted for publications in Nuclear Inst. and Methods in Physics Research, A (2023) 168253 ( https://www.sciencedirect.com/science/article/abs/pii/S0168900223002437 ); 39 pages, 14 Figure
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