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61.
The ecology of the blindsnake, Typhlops punctatus punctatus in five selected study plots in the River Niger Delta (Port Harcourt, Nigeria) was investigated. A total of 207 specimens were collected, 43% occurring under stones, 30% under leaf litter and 15% under logs. The number of snakes found under cover objects was significantly influenced by the number of cover objects lifted up. GLM analysis revealed that there was no difference in terms of number of snakes observed, once the relative effect of the different number of cover objects lifted up was taken into account, either among study plots or among types of cover objects. These snakes appeared to have a strong affinity for loamy soils, with moisture content of 8–18%, high organic matter (1–6%) and slightly acid pH of 5.4–6.9. Stomach content analysis revealed that these snakes fed mainly upon ants and termites. A case of predation by the toad Bufo maculatus on a juvenile blindsnake was also reported.  相似文献   
62.
63.
This study projects future (e.g., 2050 and 2099) grassland productivities in the Greater Platte River Basin (GPRB) using ecosystem performance (EP, a surrogate for measuring ecosystem productivity) models and future climate projections. The EP models developed from a previous study were based on the satellite vegetation index, site geophysical and biophysical features, and weather and climate drivers. The future climate data used in this study were derived from the National Center for Atmospheric Research Community Climate System Model 3.0 ‘SRES A1B’ (a ‘middle’ emissions path). The main objective of this study is to assess the future sustainability of the potential biofuel feedstock areas identified in a previous study. Results show that the potential biofuel feedstock areas (the more mesic eastern part of the GPRB) will remain productive (i.e., aboveground grassland biomass productivity >2750 kg ha?1 year?1) with a slight increasing trend in the future. The spatially averaged EPs for these areas are 3519, 3432, 3557, 3605, 3752, and 3583 kg ha?1 year?1 for current site potential (2000–2008 average), 2020, 2030, 2040, 2050, and 2099, respectively. Therefore, the identified potential biofuel feedstock areas will likely continue to be sustainable for future biofuel development. On the other hand, grasslands identified as having no biofuel potential in the drier western part of the GPRB would be expected to stay unproductive in the future (spatially averaged EPs are 1822, 1691, 1896, 2306, 1994, and 2169 kg ha?1 year?1 for site potential, 2020, 2030, 2040, 2050, and 2099). These areas should continue to be unsuitable for biofuel feedstock development in the future. These future grassland productivity estimation maps can help land managers to understand and adapt to the expected changes in future EP in the GPRB and to assess the future sustainability and feasibility of potential biofuel feedstock areas.  相似文献   
64.
The quality of day old chicks is crucial for profitable broiler production, but a difficult trait to define. In research, both qualitative and quantitative measures are used with variable predictive value for subsequent performance. In hatchery practice, chick quality is judged on a binomial scale, as chicks are divided into first grade (Q1-saleable) and second grade (Q2) chicks right after hatch. Incidences and reasons for classifying chicks as Q2, and potential of these chicks for survival and post-hatch performance have hardly been investigated, but may provide information for flock performance. We conducted an experiment to investigate (1) the quality of a broiler flock and the relation with post-hatch flock performance based on a qualitative score (Pasgar©score) of Q1 chicks and based on the incidence of Q2 chicks and (2) the reasons for classifying chicks as Q2, and the potential of these chicks for survival and post-hatch growth. The performance was followed of Q1 and Q2 chicks obtained from two breeder flocks that hatched in two different hatching systems (a traditional hatcher or a combined hatching and brooding system, named Patio). Eggs were incubated until embryo day 18, when they were transferred to one of the two hatching systems. At embryo day 21/post-hatch day 0, all chicks from the hatcher (including Q2 chicks) were brought to Patio, where the hatchery manager marked the Q2 chicks from both flocks and hatching systems and registered apparent reasons for classifying these chicks as Q2. Chick quality was assessed of 100 Q1 chicks from each flock and hatching system. Weights of all chicks were determined at days 0, 7, 21 and 42. There were no correlations between mean Pasgar©score and post-hatch growth or mortality, and suboptimal navel quality was the only quality trait associated with lower post-hatch growth. Growth was clearly affected by breeder flock and hatching system, which could not be linked to mean Pasgar©score or incidence of Q2 chicks. Q2 chicks showed lower post-hatch growth compared to Q1 chicks but effects on flock performance at slaughter weight were limited because early mortality in Q2 chicks was high (62.50% at 7 days). We concluded that chick qualitative scores and the incidence of Q2 chicks may be informative for the quality of incubation, but are not predictive for post-hatch flock performance. Culling Q2 chicks after hatch is well-founded in terms of both animal welfare and profitability.  相似文献   
65.
This article outlines the subsector of the information and communication technology (ICT) industry concerned with reducing the economy's environmental impact, dubbed ICT‐enabled low carbon technologies (ICTeLCTs). The article is based on a study funded by United Kingdom (UK) Trade and Investment, a division of the UK Department for Business, Innovation and Skills. ICTeLCTs can be segmented into specialist and generalist operators. Specialists focus on one or two ICT applications to monitor or reduce environmental issues, while generalists supply products and services enabling a firm or a private household to reduce the environmental impact of its activities. The subsector can be further segmented into green ICT, energy management, building management, carbon accounting, waste management, intelligent transport systems (ITSs), and water management. The main factors driving ICTeLCTs include legislation, voluntary environmental standards, corporate social responsibility (CSR) activities, customer demand, and competitive market factors. Policy makers should continue to drive the growth of ICTeLCTs with the introduction and refinement of environmental legislation regulating energy use and markets.  相似文献   
66.
BACKGROUND : Genetic and environmental factors likely influence susceptibility to nonsyndromic cryptorchidism, a common disease presenting at birth or in later childhood. We compared cases and controls to define differential risk factors for congenital versus acquired cryptorchidism. METHODS : We compared questionnaire and clinical data from cases of congenital cryptorchidism (n = 230), acquired cryptorchidism (n = 182) and hernia/hydrocele (n = 104) with a group of healthy male controls (n = 358). Potential predictor variables (p < 0.2 in univariable analysis) were included in stepwise multivariable logistic regression models. RESULTS : Temporary (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.4–0.8) or exclusive (OR, 0.6; 95% CI, 0.4–0.9) breastfeeding was reduced and soy formula feeding increased (OR, 1.8; 95% CI, 1.2–2.9) in acquired but not congenital or hernia/hydrocele groups. The highest risk estimates were observed for primary soy formula feeding with limited or no breastfeeding (OR 2.5; 95% CI, 1.4–4.3; adjusted OR, 2.7; 95% CI, 1.4–5.4) in the acquired group. Primary feeding risk estimates were equivalent or strengthened when multivariable models were limited to age greater than 2 years, full‐term or not small for gestational age, or Caucasian subjects. Pregnancy complications and increased maternal exposure to cosmetic or household chemicals were not consistently associated with either form of cryptorchidism in these models. CONCLUSIONS : Our data support reduced breastfeeding and soy formula feeding as potential risk factors for acquired cryptorchidism. Although additional studies are needed, hormonally active components of breast milk and soy formula could influence the establishment of normal testis position in the first months of life, leading to apparent ascent of testes in childhood. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.  相似文献   
67.
Iodine deficiency is a factor that may compromise child development, but is not the only one. Other health determinants, some of them outside the healthcare system, are able to influence development. Fighting iodine deficiency may be a pragmatic and useful strategy if it is found to be not maleficent, beneficial to health, and cost-effective, and does not make us lose the notion that child development goes beyond psychomotor or cognitive performance. This article analyzes such constraints from a critical point of view.  相似文献   
68.
1. Habitat deterioration is a major problem world-wide as a result of processes such as change in land use, introduced species, human disturbance and exploitation of food supplies. Many studies have shown that habitat change can have considerable effect on the numbers of individuals using a site. For migratory species, however, the consequences for the total population cannot be deduced from local studies.
2. For a migratory species, the change in total population size Δ N , as a consequence of habitat change in the wintering area, can be calculated from Δ N  =  LM γ d '/( b ' +  d '), where γ is the expected proportional change in the number of birds using a site as a result of the habitat change, L is the area affected, M is the density of individuals using the site prior to habitat change, b ' is the strength of the per capita density-dependent breeding output, and d ' is the strength of the per capita density-dependent winter mortality. Similarly the consequences of habitat change in the breeding area can be calculated from Δ N  =  LM γ b '/( b ' +  d ').
3. The same approach can be used for predicting the consequences of improvements in habitat quality.
4. A worked example is given to illustrate how this approach could be used to predict the consequences for the total population of changes in the food supply of oystercatchers within one estuary.
5. There is a need for more measures of γ, the expected proportional change in the number of birds using a site as a result of various forms of habitat deterioration, and the strengths of density dependence.  相似文献   
69.
This study was designed to evaluate the reproductive performance of lactating dairy cows (Holstein Friesian) after the injection of PGF analogue on Day 15 postpartum, and GnRH analogue on Day 23 after artificial insemination (AI) with Presynch (two injections of PGF, administered 14 days apart starting at 30–35 days postpartum) + Ovsynch-based (GnRH–7 days–PGF–2 days–GnRH–16–20 hours–timed artificial insemination) treatments, during the warm and cold periods of the year. All the cows (n = 313) were assigned to one of the four groups including: M1 (n = 72) in which the cows were treated with PGF on Day 15 postpartum + Presynch-Ovsynch + GnRH on Day 23 post-AI; M2 (n = 41) in which the cows received PGF on Day 15 postpartum + Presynch-Ovsynch; M3 (n = 100) including the cows that got Presynch-Ovsynch; and control group (n = 100) including the cows that were not treated and were inseminated at natural estrus. Pregnancy diagnosis was performed 28 to 35 days post-insemination by means of ultrasound. The results showed that treatment with PGF on Day 15 postpartum significantly decreased the days to conception and the number of services per conception (P < 0.01) and it also improved the first service conception rate (P < 0.1) only in cows that were treated with M2 protocol. Whereas, the days to first service was not influenced by the treatment of PGF on Day 15 postpartum (P > 0.05). In contrast, administration of GnRH on Day 23 post-AI increased the days to conception and the number of service per conception (P < 0.01) and tended to decrease the first service conception rate (P < 0.1) in cows that were treated with M1 compared with M2 protocol. Therefore, it was concluded that Presynch-Ovsynch protocol could be more reproductive and beneficial when a single treatment with PGF was administered at 15 days postpartum (15 days after the PGF, Presynch-Ovsynch protocol was initiated). Interestingly, the administration of a GnRH agonist on Day 23 post-AI not only did not improve the reproductive performance of the cows receiving first postpartum timed artificial insemination after Presynch-Ovsynch protocol but also reduced that.  相似文献   
70.
Harnessing enzyme expression for production of target chemicals is a critical and multifarious process, where screening of different genes by inspection of enzymatic activity plays an imperative role. Here, we conceived an idea to improve the time-consuming and labor-intensive process of enzyme screening. Controlling cell growth was achieved by the Cluster Regularly Interspaced Short Palindromic Repeat (CRISPRi) system with different single guide RNA targeting the essential gene can (CRISPRi::CA) that encodes a carbonic anhydrase for CO2 uptake. CRISPRi::CA comprises a whole-cell biosensor to monitor CO2 concentration, ranging from 1% to 5%. On the basis of CRISPRi::CA, an effective and simple Direct Enzymatic Performance Evaluation & Determination (DEPEND) system was developed by a single step of plasmid transformation for targeted enzymes. As a result, the activity of different carbonic anhydrases corresponded to the colony-forming units. Furthermore, the enzymatic performance of 5-aminolevulinic acid synthetase (ALAS), which converts glycine and succinate-CoA to release a molecule of CO2, has also been distinguished, and the effect of the chaperone GroELS on ALAS enzyme folding was successfully identified in the DEPEND system. We provide a highly feasible, time-saving, and flexible technology for the screening and inspection of high-performance enzymes, which may accelerate protein engineering in the future.  相似文献   
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