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排序方式: 共有229条查询结果,搜索用时 15 毫秒
221.
Gillian Eggleston Adrian Monge Armand Pepperman 《Journal of agricultural and food chemistry》2002,50(3):484-490
In the U.S., cold lime clarification remains the clarification process of choice in raw sugar manufacturing. A comparative study of cold vs intermediate lime clarification was undertaken at a factory that operated intermediate liming (approximately 30% mixed juice (MJ) of pH 5.2 +/- 0.3 was preheated to 87-93 degrees C to help maintain clean limed juice heaters, incubated at approximately 54 degrees C, and then limed) but still had the pipes to revert to cold liming (MJ incubated and limed at approximately 40 degrees C) for this study. Hourly samples were collected over a 6 h sampling period across cold and intermediate clarification processes on two consecutive days, respectively, and this was repeated three times across the 1999 grinding season. A total of 1.57% less sucrose was lost to inversion reactions across intermediate rather than cold liming. In intermediate liming, which required approximately 4.6% less lime, preheating of only 30% of the MJ markedly removed color (-29%), dextran (-10%), and starch (-24%) and caused large flocs to form that settled faster in the clarifiers. Faster settling led to an impressive 4.6% (season average) more turbidity removal across the clarifiers in intermediate rather than cold liming. Intermediate clarified juice (CJ) turbidity (season average 2028 ICU +/- 675) was approximately half of cold CJ turbidity (average 3952 ICU +/- 1450) with over 2-fold more CJ turbidity control. Subsequent turbidity values and control were significantly improved in the final evaporator syrup samples too. For both processes, juice incubation caused approximately 10% color removal, but this was offset by color formation on liming, because of the alkaline degradation of invert; however, overall, more color was removed than formed in intermediate liming. Starch was reduced in the incubator tank, for both processes, because added filtrate reduced the acidity enabling natural diastase from the cane to degrade starch. Some dextran occasionally formed in the incubator tank, in both processes. Summed across measured parameters, intermediate liming appears to offer several advantages over cold liming. 相似文献
222.
Sandra van Kuijk Ruth Kinkead Gillian Scoley Steven Morrison Yanming Han 《Journal of animal physiology and animal nutrition》2021,105(3):462-469
The aim of this study was to assess the effects of feeding immunized egg proteins (IEP) on the health and performance of newborn dairy calves. Sixty-four Holstein calves, both male and female, were divided over two treatments. Calves either received IEP or a placebo (PCB) in their colostrum and calf milk replacer (CMR) for the first 14 days of their life. Until day 49, CMR was offered at 15% of birth weight (BW), at 10% on days 49–57 and at 5% on days 57–63. In addition, calves received starter concentrate, chopped straw and water from 3 days old until 70 days old at the end of study. Individual CMR and concentrate intake were measured daily whilst BW was recorded weekly. Visual faecal scoring and health observations were conducted daily. Faecal samples were collected weekly up to 4 weeks and during the first 4 days of scouring to screen for presence of Cryptosporidium parvum, rotavirus, coronavirus, E. coli and Salmonella. Results indicated that feeding IEP increased BW (p < .05) at 42 and 56 days old, and BW also tended (p = .06) to be higher after weaning at 63–70 days old compared to the PCB group. When analysed using a repeated measures model, compared to feeding PCB, feeding IEP increased total concentrate consumption (p = .001) by 3.6kg/calf. Over the entire study, daily water intake was higher (p = .002) for the IEP group when compared with the PCB group. In the IEP group, 12 calves were scored as scouring whereas there were 14 calves in the PCB group. There were no significant differences between treatments in faecal pathogen load of neither healthy nor scouring calves. In conclusion, supplementing IEP during the first 14 days of calf life improved the performance of newborn calves. Further work is warranted to understand the mode of action of IEP in calves. 相似文献
223.
Gillian T. Braulik 《Biological conservation》2006,129(4):579-590
A survey was conducted in March and April 2001, to assess the status of the Indus River dolphin, Platanista gangetica minor, throughout its present range. A total of 1535 km of survey effort was conducted, consisting of 1375 km of the Indus River main channel, 136 km of Indus River secondary channels, and 24 km of the Panjnad River, a tributary of the Indus. The effective range of the Indus dolphin has declined by 80% since 1870. The sum of best group size estimates produced an abundance estimate of 965 dolphins. Extrapolation of encounter rates to un-surveyed channels and application of a correction factor to account for missed dolphins indicates that the metapopulation may number approximately 1200 individuals. Dolphins occur in five subpopulations separated by irrigation barrages. A pronounced increase in dolphin abundance and encounter rate was observed in each subsequent downstream subpopulation (except the last). The three largest subpopulations were between Chashma and Taunsa Barrages (84 dolphins; 0.28/km), Taunsa and Guddu Barrages (259 dolphins; 0.74/km) and Guddu and Sukkur Barrages (602 dolphins; 3.60/km). Reasons suggested for the high encounter rate between Guddu and Sukkur Barrages, include high carrying capacity, low levels of anthropogenic threat, effective conservation, and augmentation of the subpopulation by downstream migration of dolphins from upstream. 相似文献
224.
The rarity and decline of the bittern Botaurus stellaris in Britain has prompted large-scale wetland restoration and more recently, wetland creation projects. In order to guide such habitat management, we investigated whether any large or fine-scale features within British wetland sites best described the selection of female bittern nesting positions. Birds nested in continuous vegetation (usually Phragmites dominated) that was on average 100 m at its narrowest width. When compared with random locations, nests had less scrub and more vegetated open water edge in their wider vicinity and were immediately surrounded by smaller percentage coverage of non-Phragmites species and thicker Phragmites stems. Of most importance, female bitterns nested at points where deeper water was maintained into the driest part of the season, perhaps using the presence of water tolerant plant species as an indication of this. The results can be used to aid the design of new wetland sites to take into account the needs of nesting female bittern. 相似文献
225.
Lysosomes are membrane-bound organelles that are found in all mammalian cells and contain hydrolases and lipases required for protein and membrane degradation. In many cells of the immune system, lysosomes also contain secretory proteins that can be released by regulated exocytosis in response to an external stimulus, providing different cell types with a wide range of effector functions. Melanosomes also use a lysosome-related organelle to secrete melanin for pigmentation. Links between albinism and immunity in patients have uncovered a number of key proteins required for lysosomal secretion and have revealed a versatile secretory mechanism that can be fine-tuned by distinct interactions in different cell types. 相似文献
226.
Abramson J Smirnova I Kasho V Verner G Kaback HR Iwata S 《Science (New York, N.Y.)》2003,301(5633):610-615
Membrane transport proteins that transduce free energy stored in electrochemical ion gradients into a concentration gradient are a major class of membrane proteins. We report the crystal structure at 3.5 angstroms of the Escherichia coli lactose permease, an intensively studied member of the major facilitator superfamily of transporters. The molecule is composed of N- and C-terminal domains, each with six transmembrane helices, symmetrically positioned within the permease. A large internal hydrophilic cavity open to the cytoplasmic side represents the inward-facing conformation of the transporter. The structure with a bound lactose homolog, beta-D-galactopyranosyl-1-thio-beta-D-galactopyranoside, reveals the sugar-binding site in the cavity, and residues that play major roles in substrate recognition and proton translocation are identified. We propose a possible mechanism for lactose/proton symport (co-transport) consistent with both the structure and a large body of experimental data. 相似文献
227.
Nuopponen MH Birch GM Sykes RJ Lee SJ Stewart D 《Journal of agricultural and food chemistry》2006,54(1):34-40
Sitka spruce (Picea sitchensis) samples (491) from 50 different clones as well as 24 different tropical hardwoods and 20 Scots pine (Pinus sylvestris) samples were used to construct diffuse reflectance mid-infrared Fourier transform (DRIFT-MIR) based partial least squares (PLS) calibrations on lignin, cellulose, and wood resin contents and densities. Calibrations for density, lignin, and cellulose were established for all wood species combined into one data set as well as for the separate Sitka spruce data set. Relationships between wood resin and MIR data were constructed for the Sitka spruce data set as well as the combined Scots pine and Sitka spruce data sets. Calibrations containing only five wavenumbers instead of spectral ranges 4000-2800 and 1800-700 cm(-1) were also established. In addition, chemical factors contributing to wood density were studied. Chemical composition and density assessed from DRIFT-MIR calibrations had R2 and Q2 values in the ranges of 0.6-0.9 and 0.6-0.8, respectively. The PLS models gave residual mean squares error of prediction (RMSEP) values of 1.6-1.9, 2.8-3.7, and 0.4 for lignin, cellulose, and wood resin contents, respectively. Density test sets had RMSEP values ranging from 50 to 56. Reduced amount of wavenumbers can be utilized to predict the chemical composition and density of a wood, which should allow measurements of these properties using a hand-held device. MIR spectral data indicated that low-density samples had somewhat higher lignin contents than high-density samples. Correspondingly, high-density samples contained slightly more polysaccharides than low-density samples. This observation was consistent with the wet chemical data. 相似文献
228.
Foulger GR 《Science (New York, N.Y.)》2006,313(5788):768-769
229.
Gillian Bloomfield Karin Bucht José Carlos Martínez-Hernández Aníbal F. Ramírez-Soto Ixchel Sheseña-Hernández César Raziel Lucio-Palacio 《Journal of Sustainable Forestry》2018,37(2):157-177
The United Nations sustainable development goals (SDGs) provide an ambitious and comprehensive framework for addressing the development needs on a global, regional, and national scale. In order for the SDG targets to be obtainable, diverse stakeholders need the technical, institutional, and organizational capacity to implement the wide variety of initiatives covered under these goals. Inspired by a 2016 workshop, this article synthesizes capacity-building themes and strategies for the following approaches to sustainable development, specifically related to forestry, restoration, agriculture, and other forms of land management. Using three case studies from the authors’ experience, we present approaches to building local capacity for sustainable land management (SLM) in the tropics. These projects have taken different steps in order to build technical and leadership capacity as well as develop management or financial skills, and offer insight into various approaches that may be used in order to improve the effectiveness and long-term impact of SLM efforts. By presenting a range of tools and approaches to capacity building, the authors hope that this synthesis can serve as a valuable guide for the development of diverse capacity-building initiatives required to meet the SDGs. 相似文献