2,592 research outputs found
Fermentation Parameters of Kikuyu Grass (\u3cem\u3ePennisetum clandestinum\u3c/em\u3e) by \u3cem\u3ein Vitro\u3c/em\u3e Gas Production Technique (IVGPT)
Methane (CH4) is a byproduct of ruminal fermentation whose production is directly related to forage quality, which in turn is affected by a myriad of environmental factors. In general the quality of pastures in the tropics range from medium to poor due to a high content of lignocellulosic material of low digestibility and a low content of other components, such as soluble carbohydrates and protein (Correa et al, 2008). CH4 produced by enteric fermentation from cattle rumen represents a major source of greenhouse gases (GHG). By measuring these emissions the impact of dairy production systems on the climate change can be determine.
In Colombia and in specifically in the Department of Antioquia, dairy herds are characterized by using diets based on kikuyu grass (Pennisetum clandestinum) supplemented with concentrates. Once in the rumen the forage /concentrate combination are used as substrate for ruminal fermentation to generate usable energy but also unusable one represented by methane production. The energy losses due to diets based on kikuyu are unknown. Thus, the measurement of its fermentation products has become an important necessity in order to achieve greater efficiencyin the livestock production systems which are also environmentally friendly and economically competitive. Despite some important progress in Colombia, the potential impact of livestock on global warming is still unknown so that measuring of CH4 emissions is a crucial imperative. In the dairy zone located in the northern part of Antioquia, where daily two millions liters of milk are produced, there are around 185,000 ha in kikuyu pasture. The overall objective of this research was to measure the parameters of fermentation and CH4 production of kikuyu pastures from dairy systems of Antioquia, using the in vitro gas production technique (IVGPT)
Effects of Different Feed Additives on Methane Emissions from Beef Cattle
The rate of accumulation of methane in the atmosphere from enteric fermentation in cattle has an important impact on the greenhouse effect and contributing to global warming. Additionally, methane emission reduces the energy efficiency of substrate fermention in the rumen. Under-standing the effect of the diet on enteric methane emissions could help to identify strategies to reduce emissions of this greenhouse gas. Therefore, the main objective of the present investigation was to determine the effect of nutritional additives such as monensin, fumaric acid, tannins of Acacia decurrens, and glycerol on methane production and other measures of fermentation characteristics using the in vitro rumen fermentation technique and ruminal fluid obtained from cattle fed with a base diet of Pennisetum clandestinum
Evaluation of two approaches to lysosomal acid lipase deficiency patient identification: An observational retrospective study
Background and aims: Lysosomal acid lipase deficiency (LALD) leads to the accumulation of cholesteryl esters and/or triglycerides (TG) in lysosomes due to the lack of the enzyme codified by the LIPA gene. The most common symptoms are dyslipidaemia and hypertransaminasemia, together with manifestations common to other lysosomal storage disorders (LSDs), including visceromegalies and elevated plasma biomarkers. Alteration of the lipid-liver profile (LLP) has been widely applied as a criterion for LALD screening, but the usefulness of biomarkers has not yet been explored. Our purpose was to explore the utility of plasma chitotriosidase activity (ChT) and CCL18/PARC concentration in addition to LLP to identify LALD patients in an observational retrospective study of two different sample collections.
Methods: Biological samples refining: Collection 1 (primary hypercholesterolemia suspected) included unrelated individuals with hyperlipidaemia and without LDLR, APOB and PCSK9 gene mutations (Set 1), and Collection 2 (LSD suspected) included individuals without definitive LSD diagnosis (Set 2). We assessed plasma LLP (total cholesterol and its fractions, TG concentration and transaminases activities), as well as plasma ChT and CCL18/PARC. All subjects with anomalous LLP and/or biomarker levels were LIPA sequenced.
Results: Twenty-four subjects showed altered LLP and/or biomarkers. We identified two LALD patients (one homozygous and one compound heterozygous) and one carrier of a novel LIPA variant.
Conclusions: The measurement of plasma ChT and CCL18/PARC combined with LLP will be a useful approach to identifying LALD patients in retrospective LALD patient studies
Using the heart rate variability for classifying patients with and without chronic heart failure and periodic breathing
Assessment of the dynamic interactions between cardiovascular signals can provide valuable information that improves the understanding of cardiovascular control. Heart rate variability (HRV) analysis is known to provide information about the autonomic heart rate modulation mechanism. Using the HRV signal, we aimed to obtain parameters for classifying patients with and without chronic heart failure (CHF), and with periodic breathing (PB), non-periodic breathing (nPB), and Cheyne-Stokes respiration (CSR) patterns. An electrocardiogram (ECG) and a respiratory flow signal were recorded in 36 elderly patients: 18 patients with CHF and 18 patients without CHF. According to the clinical criteria, the patients were classified into the follow groups: 19 patients with nPB pattern, 7 with PB pattern, 4 with Cheyne-Stokes respiration (CSR), and 6 non-classified patients (problems with respiratory signal). From the HRV signal, parameters in the time and frequency domain were calculated. Frequency domain parameters were the most discriminant in comparisons of patients with and without CHF: PTOT, PLF and fpHF. For the comparison of the nPB vs CSR patients groups, the best parameters were RMSSD and SDSD. Therefore, the parameters appear to be suitable for enhanced diagnosis of decompensated CHF patients and the possibility of developed periodic breathing and a CSR pattern
Anomalous relaxation kinetics and charge density wave correlations in underdoped BaPb1-xBixO3
Superconductivity often emerges in proximity of other symmetry-breaking
ground states, such as antiferromagnetism or charge-density-wave (CDW) order.
However, the subtle inter-relation of these phases remains poorly understood,
and in some cases even the existence of short-range correlations for
superconducting compositions is uncertain. In such circumstances, ultrafast
experiments can provide new insights, by tracking the relaxation kinetics
following excitation at frequencies related to the broken symmetry state. Here,
we investigate the transient terahertz conductivity of BaPb1-xBixO3 - a
material for which superconductivity is adjacent to a competing CDW phase -
after optical excitation tuned to the CDW absorption band. In insulating BaBiO3
we observed an increase in conductivity and a subsequent relaxation, which are
consistent with quasiparticles injection across a rigid semiconducting gap. In
the doped compound BaPb0.72Bi0.28O3 (superconducting below Tc=7K), a similar
response was also found immediately above Tc. This observation evidences the
presence of a robust gap up to T=40 K, which is presumably associated with
short-range CDW correlations. A qualitatively different behaviour was observed
in the same material fo T>40 K. Here, the photo-conductivity was dominated by
an enhancement in carrier mobility at constant density, suggestive of melting
of the CDW correlations rather than excitation across an optical gap. The
relaxation displayed a temperature dependent, Arrhenius-like kinetics,
suggestive of the crossing of a free-energy barrier between two phases. These
results support the existence of short-range CDW correlations above Tc in
underdoped BaPb1-xBixO3, and provide new information on the dynamical interplay
between superconductivity and charge order.Comment: 19 pages, 4 figure
Dyes removal from water using low cost absorbents
In this study, the removal capacity of low cost adsorbents during the adsorption of Methylene Blue (MB) and Congo Red (CR) at different concentrations (50 and 100mg•L-1) was evaluated. These adsorbents were produced from wood wastes (cedar and teak) by chemical activation (ZnCl2). Both studied materials, Activated Cedar (AC) and activated teak (AT) showed a good fit of their experimental data to the pseudo second order kinetic model and Langmuir isotherms. The maximum adsorption capacities for AC were 2000.0 and 444.4mg•g-1 for MB and CR, respectively, while for AT, maximum adsorption capacities of 1052.6 and 86.4mg•g-1 were found for MB and CR, respectively. © Published under licence by IOP Publishing Ltd
- …