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121.
122.
N.J. RodgersM. Choct H. HetlandF. Sundby B. Svihus 《Animal Feed Science and Technology》2012,171(1):60-67
A broiler experiment was conducted to examine the effects of sorghum particle size and milling type on the performance, nitrogen corrected apparent metabolisable energy (AMEn), digestive tract development, digesta pH, duodenal digesta particle size and digesta passage rate. Complete pelleted diets with identical botanical and chemical composition containing 750 g/kg whole sorghum (WS), sorghum ground through hammer mill with 1 mm and 3 mm screen (HM1 and HM3) and sorghum ground on a roller mill with 0.15 mm spacing (RM0.15), were made. Sorghum for diets HM3 and RM0.15 were milled to approximately the same mean particle size. Diet WS resulted in poorer (P<0.05) weight gain and feed conversion ratio (FCR) than the other diets from 11 to 21 days of age, while diet RM0.15 resulted in improved FCR. Apparent MEn determined between 25 and 28 days of age, however, was higher (P<0.05) for diet WS than for the other diets. This was possibly due to a longer adaptation time to a larger feed particle size, as indicated by a lower (P<0.05) pH in the gizzard and smaller duodenal digesta particle size for this diet. Diet HM1 gave similar performance as diet HM3, but resulted in a significantly smaller gizzard, a higher pH of the gizzard content, a lower pH of the duodenal content and larger particles in the duodenal contents, thus indicating that gizzard development and activity were compromised by this diet. Total tract passage rate of the liquid phase marker was slower (P<0.05) in the WS fed birds, but there were no differences in solid phase marker excretion rates. 相似文献
123.
Shuang-He Shen Shen-Bin Yang Yan-Xia Zhao Yin-Long Xu Xiao-Yan Zhao Zhu-Yu Wang Juan Liu Wei-Wei Zhang 《生态学报》2011,31(1):40-48
As one of the most important crops in China, rice accounts for 18% of the country’s total cultivated area. Increasing atmospheric CO2 concentration and associated climate change may greatly affect the rice productivity. Therefore, understanding the impacts of climate change on rice production is of great significance. This paper aims to examine the potential impacts of future climate change on the rice yield in the middle and lower reaches of the Yangtze River, which is one of the most important food production regions in China. Climate data generated by the regional climate Model PRECIS for the baseline (1961–1990) and future (2021–2050) period under IPCC SRES B2 scenario were employed as the input of the rice crop model ORYZA2000. Four experimental schemes were carried out to evaluate the effects of future climate warming, CO2 fertilization and water managements (i.e., irrigation and rain-fed) on rice production. The results indicated that the average rice growth duration would be shortened by 4 days and the average rice yield would be declined by more than 14% as mean temperature raised by 1.5 °C during the rice growing season in 2021–2050 period under B2 scenario. This negative effect of climate warming was more obvious on the middle and late rice than early rice, since both of them experience higher mean temperature and more extreme high temperature events in the growth period from July to September. The significance effect of the enhanced CO2 fertilization to rice yield was found under elevated CO2 concentrations in 2021–2050 period under B2 scenario, which would increase rice yield by more than 10%, but it was still not enough to offset the negative effect of increasing temperature. As an important limiting factor to rice yield, precipitation contributed less to the variation of rice yield than either increased temperature or CO2 fertilization, while the spatial distribution of rice yield depended on the temporal and spatial patterns of precipitation and temperature. Compared to the rain-fed rice, the irrigated rice generally had higher rice yield over the study area, since the irrigated rice was less affected by climate change. Irrigation could increase the rice yield by more than 50% over the region north of the Yangtze River, with less contribution to the south, since irrigation can relieve the water stress for rice growing in the north region of the study area. The results above indicated that future climate change would significantly affect the rice production in the middle and lower reaches of the Yangtze River. Therefore, the adverse effect of future climate change on rice production will be reduced by taking adaptation measures to avoid disadvantages. However, there is uncertainty in the rice production response prediction due to the rice acclimation to climate change and bias in the simulation of rice yield with uncertainty of parameters accompanied with the uncertainty of future climate change scenario. 相似文献
124.
Determination of tropical deforestation rates and related carbon losses from 1990 to 2010 总被引:4,自引:0,他引:4
Frédéric Achard René Beuchle Philippe Mayaux Hans‐Jürgen Stibig Catherine Bodart Andreas Brink Silvia Carboni Baudouin Desclée François Donnay Hugh D. Eva Andrea Lupi Rastislav Raši Roman Seliger Dario Simonetti 《Global Change Biology》2014,20(8):2540-2554
We estimate changes in forest cover (deforestation and forest regrowth) in the tropics for the two last decades (1990–2000 and 2000–2010) based on a sample of 4000 units of 10 ×10 km size. Forest cover is interpreted from satellite imagery at 30 × 30 m resolution. Forest cover changes are then combined with pan‐tropical biomass maps to estimate carbon losses. We show that there was a gross loss of tropical forests of 8.0 million ha yr?1 in the 1990s and 7.6 million ha yr?1 in the 2000s (0.49% annual rate), with no statistically significant difference. Humid forests account for 64% of the total forest cover in 2010 and 54% of the net forest loss during second study decade. Losses of forest cover and Other Wooded Land (OWL) cover result in estimates of carbon losses which are similar for 1990s and 2000s at 887 MtC yr?1 (range: 646–1238) and 880 MtC yr?1 (range: 602–1237) respectively, with humid regions contributing two‐thirds. The estimates of forest area changes have small statistical standard errors due to large sample size. We also reduce uncertainties of previous estimates of carbon losses and removals. Our estimates of forest area change are significantly lower as compared to national survey data. We reconcile recent low estimates of carbon emissions from tropical deforestation for early 2000s and show that carbon loss rates did not change between the two last decades. Carbon losses from deforestation represent circa 10% of Carbon emissions from fossil fuel combustion and cement production during the last decade (2000–2010). Our estimates of annual removals of carbon from forest regrowth at 115 MtC yr?1 (range: 61–168) and 97 MtC yr?1 (53–141) for the 1990s and 2000s respectively are five to fifteen times lower than earlier published estimates. 相似文献
125.
XinJun Hu Ang Li LongXian Lv Chunhui Yuan Lihua Guo Xiawei Jiang Haiyin Jiang GuiRong Qian BeiWen Zheng Jing Guo LanJuan Li 《Standards in genomic sciences》2014,9(3):755-762
Staphylococcus cohnii subsp. cohnii belongs to the family Staphylococcaceae in the order Bacillales, class Bacilli and phylum Firmicutes. The increasing relevance of S. cohnii to human health prompted us to determine the genomic sequence of Staphylococcus cohnii subsp. cohnii strain hu-01, a multidrug-resistant isolate from a hospital in China. Here we describe the features of S. cohnii subsp. cohnii strain hu-01, together with the genome sequence and its annotation. This is the first genome sequence of the species Staphylococcus cohnii. 相似文献
126.
Louis Steyn Anandi Bierman N. Francois V. Burger Anna‐Maria Botha 《Entomological Science》2020,23(1):86-94
We present the first sequencing results after separation of the X chromosome of Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), the largest known X chromosome described to date, using flow cytometry. The X chromosome of D. noxia is 0.1824 pg (1C) and an estimated 178.4 Mb (1C) in size. Mapping confirmed that the X chromosome contains 13,799 protein coding genes, but with a slight bias towards GC richness when compared to the complete D. noxia genome. 相似文献
127.
Monika Lik 《法国昆虫学会纪事》2013,49(3-4):425-438
This study presents qualitative and quantitative research on communities of ground beetles (Carabidae) occurring in 2001 and 2003 in three types of habitats located near Bydgoszcz city, Poland (UTM CD19), on the Vistula river floodplain: elm and ash riparian forest (RF), poplar monoculture (P), and unintensively-farmed meadows (M). During both studied years 57 species of ground beetles were found in riparian forests (RF), 56 species in plot P and 47 in plot M. In 2001 from all sample plots 3845 beetles were collected; in 2003- 9589. In both years most specimens came from plot RF (3123 in 2001 and 6224 in 2003). From plot P 2656 specimens of ground beetles were collected and from plot M 1430 specimens. Statistically significant differences were found in the abundance of Carabidae, among sampling areas and the years of study. 相似文献
128.
Thomas Steenpaß 《生物化学与生物物理学报:生物膜》2006,1758(1):20-28
A simple and inexpensive method for functionalization of preformed liposomes is presented. Soy sterol-PEG1300 ethers are activated by tresylation at the end of the PEG chain. Coupling of bovine serum albumin as an amino group containing model ligand to the activated lipids can be performed at pH 8.4 with high efficiency. At room temperature, the mixture of sterol-PEG and sterol-PEG-protein inserts rapidly into the outer liposome monolayer with high efficiency (>100 μg protein/μmol total lipid). This method of post-functionalization is shown to be effective with fluid or rigid and plain or pre-PEGylated liposomes (EPC/Chol, 7:3; HSPC/Chol 2:1, and EPC/Chol/MPEG2000-DSPE 2:1:0.16 molar ratios). The release of entrapped calcein upon the insertion of 7.5 mol% of the functionalized sterols is lower than 4%. Incubation of post-functionalized liposomes with serum for 20 h at 37 °C shows stable protein attachment at the liposome surface. 相似文献
129.
Spyros Tsiftsis Ioannis Tsiripidis Vasiliki Karagiannakidou 《Biodiversity and Conservation》2009,18(7):1765-1780
The establishment of a network of reserves is of fundamental importance to the loss of biodiversity. Seven different area
selection methods for the establishment of a reserve network were applied in the present study: (a) 5% cut-off value of the
grid cells with the highest species richness or conservation value, (b) complementarity analysis using as criteria species
richness or conservation value or rarest species richness, and (c) mixed complementarity analysis using as criteria species
richness or conservation value. These methods were applied in the orchid taxa of east Macedonia. The conservation values of
taxa were estimated on the basis of regional rarity, broad-scale rarity, and species specialization. The spatial overlap between
the resulting networks and the Natura 2000 network of the study area was assessed. Furthermore, the efficiency of the latter
network to protect the orchid taxa of the study area was examined. Our results suggest that: (a) a multiscale estimation of
rarity is necessary for the unbiased estimation of species conservation values; (b) species specialization adds valuable ecological
information to the assessment of taxa conservation values; (c) complementarity and mixed complementarity analyses on species
richness or conservation value safeguard all the taxa of the region; (d) complementarity analysis on the basis of the richness
of the rarest species safeguards all the rarest taxa, but not the total number of the remaining taxa; (e) the 5% cut-off value
on species richness or conservation value fails to protect all the taxa of the region, including a large number of the rarest
taxa; and (f) the Natura 2000 network, despite its large coverage in the study area, fails to safeguard all the taxa, including
some of the rarest. 相似文献
130.
Question : How do interactions between rocky landscape features and fire regime influence vegetation dynamics? Location : Continental Eastern USA. Methods : We measured vegetation, disturbance and site characteristics in 40 pairs of rocky and non‐rocky plots: 20 in recently burned stands, and 20 in stands with no evidence of recent fire (‘unburned’ stands). Two‐way analysis of variance (ANOVA) was used to assess the main and interaction effects of fire and rock cover on plant community composition. Results : In burned stands, rock cover had a strong influence on vegetation. Non‐rocky ‘matrix’ forests were dominated by Quercus, and had abundant ground cover and advance regeneration of early and mid‐successional tree species. Burned rocky patches supported greater density of fire‐sensitive species such as Acer rubrum, Sassafras albidum and Nyssa sylvatica and had little advance regeneration or ground cover. Quercus had fewer fire scars and catfaces (open, basal wounds) on rocky patches, suggesting that rocky features mitigate fire severity. In unburned stands, differences between rocky and non‐rocky patches were less distinct, with both patch types having sparse ground cover, little tree regeneration, and high understorey densities of relatively shade tolerant A. rubrum, N. sylvatica and Betula lenta. Conclusion : Under a sustained fire regime, heterogeneity in rock cover created a mosaic where fire‐adapted species such as Quercus dominate the landscape, but where fire‐sensitive species persisted in isolated pockets of lower fire severity. Without fire, species and landscape richness may decline as early‐mid successional species are replaced by more shade tolerant competitors. 相似文献