54 research outputs found

    Arithmetical structures on bidents

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    An arithmetical structure on a finite, connected graph GG is a pair of vectors (d,r)(\mathbf{d}, \mathbf{r}) with positive integer entries for which (diag(d)A)r=0(\operatorname{diag}(\mathbf{d}) - A)\mathbf{r} = \mathbf{0}, where AA is the adjacency matrix of GG and where the entries of r\mathbf{r} have no common factor. The critical group of an arithmetical structure is the torsion part of the cokernel of (diag(d)A)(\operatorname{diag}(\mathbf{d}) - A). In this paper, we study arithmetical structures and their critical groups on bidents, which are graphs consisting of a path with two "prongs" at one end. We give a process for determining the number of arithmetical structures on the bident with nn vertices and show that this number grows at the same rate as the Catalan numbers as nn increases. We also completely characterize the groups that occur as critical groups of arithmetical structures on bidents.Comment: 32 page

    Application of mathemathical models to infrared assisted drying process of lemon waste (Citrus limon (l.) Burm. F. Cv. genova)

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    Los desechos agroindustriales son uno de los principales problemas ambientales a nivel mundial. Debido a las altas exigencias de calidad, la comercialización de limones de exportación genera grandes cantidades de desechos. Los descartes de limón contienen fibra, pectina, potasio, calcio y vitamina C. Por lo tanto, es importante desarrollar alternativas de procesamiento de estos sub-productos para agregarles valor y aumentar su vida útil. El objetivo de la presente investigación fue la aplicación del secado asistido por infrarrojos, como tecnología emergente, para estudiar el efecto de la temperatura de proceso sobre las cinéticas de secado de descartes de limón a 30, 40 y 50°C. Se utilizaron seis modelos matemáticos de capa fi na encontrados en literatura para representar la cinética experimental. Basándose en análisis estadístico, el modelo Logarítmico presentó el mejor ajuste. Los valores de la difusividad efectiva del agua se estimaron en el rango de 9.45× 10-10 – 3.71× 10-9 m/s2 . El valor de la energía de activación fue 55.90 kJ/mol.Agroindustrial wastes are a major environmental problem worldwide. Due to high quality requirements, commercialization of export lemons generates huge amounts of wastes. Lemon wastes have fi ber, pectin, potassium, calcium and vitamin C. Therefore, it is important to develop alternative processing methods to add value and improve their shelf life. The aim of this work was to apply infrared drying, as an emergent technology, to study the effect of drying temperature on the drying kinetics of lemon waste at 30, 40 and 50°C. Six thin layer models found in literature were used to represent the experimental drying kinetics. Based on statistical tests, the Logarithmic model presented the best fi t. Values of moisture effective diffusivities were in the range of 9.45× 10-10 ? 3.71× 10-9 m/s2 . The value of activation energy was 55.90 kJ/mol.Fil: Puente Diaz, Luis. Universidad Católica de Chile. Facultad de Ciencias Químicas y Farmacéuticas; ChileFil: Echegaray Pacheco, Eric. Universidad Católica de Chile. Facultad de Ciencias Químicas y Farmacéuticas; ChileFil: Castro Montero, Eduardo. Universidad Católica de Chile. Facultad de Ciencias Químicas y Farmacéuticas; ChileFil: Di Scala, Karina Cecilia. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata; Argentin

    Empowerment Evaluation in Spain: The Critical Friend Role in Working with Rural Communities

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    Rural communities in Cuenca (Spain) are characterized by a great social dislocation, mostly due to the low population density in these areas. In this way, the existence of groups of citizens able to be active agents of their development process is a critical aspect for any community-based development process in this Spanish region. The Institute of Community Development of Cuenca (IDC) has been working with this type of groups for the last 30 years focusing on the organizational empowerment of the rural communities. Main tools in this process have been the empowerment evaluation approach and the critical friend role when helping the groups to achieve their objectives and reinforcing them. This chapter analyses the empowerment process and how the critical friend role is nourished by the facilitator figure

    Influence of Salix babylonica and Leucaena leucocephala leaf extracts on ruminal fermentation characteristics, urinary purine derivative excretion and microbial protein synthesis of lambs

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    Extract of L. leucocephala or S. babylonica leaves was prepared as described before in Salem et al. (2011a). Briefly, leaves of each tree species were collected randomly from several young and mature trees during summer. Leaves (1.25 kg) were fresh chopped into 1 to 2 cm lengths and immediately extracted in 10 l of a solvent mixture containing 1 l of methanol, 1 l of ethanol and 8 l of distilled water. Extraction was at 25–301 C for 48–72 h in 20 l closed jars, followed by incubation at 391 C for 1 h, and then filtered. Filtrates were collected and stored at 41 C for further use. Plant extracts were weekly prepared. The 1:1 mixture extract was also prepared weekly by mixing the SB and LL extracts (0.5:0.5, vol:vol).Sixteen growing Katahdin Pelibuey lambs (2470.3 kg body weight) were used to study the effects of oral administration of extracts of Salix babylonica (SB) and Leucaena leucocephala (LL) leaves on ruminal pH, total and individual volatile fatty acids (VFA) and NH3-N concentrations, as well as ruminal protozoal counts, urinary purine derivatives (PD) excretion and estimated microbial protein synthesis. Lambs were fed a total mixed ration (TMR) containing 219 and 141 g kg 1 of CP and NDF, respectively. Four treatments (4 lambs/treatment) were Control (no extract added), SB (SB extract at 30 ml d 1), LL (LL extract at 30 ml d 1) and SBLL (mixture of SB at 15 ml d 1þLL at 15 ml d 1). Extracts were administered orally to each lamb before the morning meal daily. Measurements were on days 22 (P1), 43 (P2) and 63 (P3) of the experiment. Ruminal pH increased (P¼0.014) with SBLL extract and decreased with SB. The ratio of acetate to propionate was higher (P¼0.042) with SBLL compared to the control. Ruminal NH3-N concentration was not affected by extract administration (P¼0.309) or experimental period (P¼0.087). Protozoal counts were not affected (P¼0.489) by extract addition but decreased (Po0.001) in P3 compared with P1 and P2. Uric acid concentration increased (Po0.001) with individual extracts of SB and LL compared with the control or SBLL. Excretion of other purine derivatives (allantoin, xanthine, and hypoxanthine), creatinine and microbial protein synthesis were not changed (P40.05) by extracts administration. Overall, oral administration of S. babylonica and L. leucocephala extracts, or their 1:1 mixture, to lambs for 63 d had only minor effects on ruminal fermentation, urinary purine derivative excretion and microbial protein synthesis

    Influence of the addition of exogenous xylanase with or without pre-incubation on the in vitro ruminal fermentation of three fibrous feeds

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    These by-products could be used as animal feedstuffs, but their use is limited by their high fibre content, which invariably lowers the efficiency of digestive utilization (Khattab et al. 2013; Kholif et al. 2014). Fibrous feeds are characterized by high lignocellulose content, low crude protein (CP) content, poor palatability, and low nutrient digestibility (Kholif et al. 2014; Togtokhbayar et al. 2015). The structural carbohydrates of the fibre are less digestible than other nutrients, and the cell wall (mainly the lignin) may be a physical barrier for the bacterial attachment and the access of ruminal enzymes resulting in limited ruminal degradability (Karunanandaa et al. 1995)The effects of the exogenous fibrolytic enzyme (ENZ) commercial preparation Dyadic® xylanase PLUS (Dyadic International, Inc., Jupiter, USA), containing endo-1,4-β-d-xylanase, on ruminal fermentation of maize stover, oat straw, and sugarcane bagasse were examined using the in vitro gas production (GP) technique. The ENZ commercial preparation was added at 0 (control), 60 (low), 120 (medium), and 240 (high) μg/g dry matter of substrate, and at two times of application (direct addition just before fermentation or with a 72-h pre-incubation before fermentation). Ruminal GP volumes were recorded at 2, 4, 6, 8, 10, 12, 14, 24, and 48 h of incubation, and substrate degradability and concentration of fermentation end-products (volatile fatty acids, ammonia, methane) in the cultures were determined at 48 h of incubation. Increased (P 0.05) by ENZ application in maize stover and oat straw. However, total and individual VFA concentrations, and CH4 and CO2 volumes were greater (P < 0.05) when sugarcane bagasse was incubated with 240 μg ENZ/g (P < 0.05). It can be concluded that the application of endo-1,4-β-d-xylanase enhances rumen fermentation of roughages, although the magnitude of the effects depends on the fibrous substrate fermented, the time of application, and the amount of enzyme added

    Data preprocessing workflow for exhaled breath analysis by GC/MS using open sources

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    © 2020 The Authors. This document is made available under the CC-BY 4.0 license. http://creativecommons.org/licenses/by /4.0/ This document is the Accepted version of a Published Work that appeared in final form in Scientifc Reports. To access the final edited and published work see https://doi.org/10.1038/s41598-020-79014-

    Effects of xylanase supplementation on feed intake, digestibility and ruminal fermentation in Rambouillet sheep

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    The present study aimed to investigate the effects of adding xylanase enzyme (XY) to a basal diet containing 300 g maize stover and 700 g concentrate/kg dry matter (DM) on feed intake, ruminal fermentation, total tract and ruminal digestibility, as well as some blood parameters. Four male Rambouillet sheep (39 ± 1·8 kg body weight), with permanent rumen and duodenum cannulae were used in a 4 × 4 Latin square design. Sheep were fed a basal diet without xylanase addition (control, XY0), or with the addition of xylanase at 1 (XY1), 3 (XY3) or 6 (XY6) μl/g of diet DM for 84 days, with four 21-day experimental periods. Feed intake, digestibility and rumen fermentation parameterswere determined on days 16–21 in each experimental period, and the apparent ruminal neutral detergent fibre (NDF) digestibilitywas determined on days 16 and 17. Treatments XY1 and XY3 increased feed intake,whereas digestibility was increased with XY6. Ruminal NDF digestibility increased when sheep were fed diets treated with xylanase. Ruminal pH, ammonia-N and acetic acid increased with xylanase treated diets. Propionic acid concentration increasedwith diet XY1 at 3 h post-feeding, but after 9 h post-feeding its concentration decreased in the rumen of sheep fed xylanase treated diets. Xylanase had no effect on blood urea, phosphorus and triglycerides. Addition of xylanase at 6 μl/g DM in a diet containing 300 g maize stover and 700 g concentrate/kg DM and fed to Rambouillet sheep improved feed digestibility and ruminal fermentation without affecting blood parameters

    Exhaled volatilome analysis as a useful tool to discriminate asthma with other coexisting atopic diseases in women of childbearing age

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    ©2021. The authors. This document is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by /4.0/ This document is published version of a Published Work that appeared in final form in Scientifc Reports. To access the final edited and published work see https://doi.org/10.1038/s41598-021-92933-2The prevalence of asthma is considerably high among women of childbearing age. Most asthmatic women also often have other atopic disorders. Therefore, the diferentiation between patients with atopic diseases without asthma and asthmatics with coexisting diseases is essential to avoid underdiagnosis of asthma and to design strategies to reduce symptom severity and improve quality of life of patients. Hence, we aimed for the frst time to conduct an analysis of volatile organic compounds in exhaled breath of women of childbearing age as a new approach to discriminate between asthmatics with other coexisting atopic diseases and non-asthmatics (with or without atopic diseases), which could be a helpful tool for more accurate asthma detection and monitoring using a noninvasive technique in the near future. In this study, exhaled air samples of 336 women (training set (n= 211) and validation set (n= 125)) were collected and analyzed by thermal desorption coupled with gas chromatography-mass spectrometry. ASCA (ANOVA (analysis of variance) simultaneous component analysis) and LASSO+LS (least absolute shrinkage and selection operator+ logistic regression) were employed for data analysis. Fifteen statistically signifcant models (p-value< 0.05 in permutation tests) that discriminated asthma with other coexisting atopic diseases in women of childbearing age were generated. Acetone, 2-ethyl-1-hexanol and a tetrahydroisoquinoline derivative were selected as discriminants of asthma with other coexisting atopic diseases. In addition, carbon disulfde, a tetrahydroisoquinoline derivative, 2-ethyl-1-hexanol and decane discriminated asthma disease among patients with other atopic disorders. Results of this study indicate that refned metabolomic analysis of exhaled breath allows asthma with other coexisting atopic diseases discrimination in women of reproductive ag
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