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31.
High infant mortality and high mortality for late adolescent and young adult females suggest that obstetrical hazards may be one explanation for differences in male and female mortality curves. This possibility is investigated in Arikara skeletal series by determining the frequency of females who died with fetal remains in utero. Two females (0.9%) were so identified. Examination of the females and the fetal remains do not provide evidence that stress of childbearing was the cause of death in these cases.  相似文献   
32.
Sawdust was composted by inoculation with a cellulose-decomposing fungus (Cephalosporium sp.) and an N2-fixing bacterium (Azospirillum brasilense). The product was investigated as a possible carrier for Bradyrhizobium, Rhizobium and Azospirillum. The simple technology and composition of the carrier supported good growth and survival of the investigated strains. Yield increases following crop inoculation with the carrier containing the Bradyrhizobium/Rhizobium/Azospirillum mixture were observed with soybean (34–62%), groundnuts (4–39%), lucerne (24–82%) and a grass mixture of bird's foot trefoil and ryegrass (20–21%).  相似文献   
33.
BackgroundCancer is one of the most common causes of death. Excess body weight (EBW), a risk factor for cancer, is highly prevalent in China. We aimed to estimate the number and proportion of cancer deaths attributed to EBW and their changes during 2006–2015 in China.MethodsPopulation attributable fractions in 2006, 2010, and 2015 were calculated with 1) prevalence of overweight/obesity, exacted from the China Health and Nutrition Survey conducted in 8–9 provinces of China in 1997, 2000, and 2004; 2) relative risks for EBW and site-specific cancers, obtained from previous studies; 3) data on cancer deaths in 2006, 2010, and 2015, originated from the Chinese Cancer Registry Annual Report.ResultsIn 2015, EBW contributed to 45,918 (3.1% of all) cancer deaths in China, with 24,978 (2.6%) in men and 20,940 (3.8%) in women. By region, the fraction of cancer deaths attributable to EBW ranged from 1.6% (West) to 4.1% (Northeast). Cancers of liver, stomach, and colorectum were the main EBW-attributable cancers. The fractions of cancer deaths attributable to EBW were 2.4% (95%CI: 0.8–4.2%) in 2006, 2.9% (95%CI: 1.0–5.2%) in 2010, and 3.1% (95%CI: 1.0–5.4%) in 2015, respectively, and increased for all gender, region, and cancer site during 2006–2015.ConclusionsThe proportion of cancer deaths attributed to EBW was higher in women and Northeastern China, with an upward trend in the recent decade. A combination of comprehensive and individualized measures is necessary to reduce the prevalence of EBW and related cancer burden in China.  相似文献   
34.

Crassostrea madrasensis is an important fouling oyster in tropical industrial cooling water systems. C. madrasensis individuals attach to surfaces by cementing one of their two valves to the substratum. Therefore, oyster fouling creates more problems than mussel fouling in the cooling conduits of power stations, because unlike the latter, the shell of the former remains attached to the substratum even after the death of the animal. However, there are no published reports on the tolerance of this species to chlorination and heat treatment. The mortality pattern and physiological behaviour (oxygen consumption and filtration rate) of three size groups (13 mm, 44 mm and 64 mm mean shell length) of C. madrasensis were studied at different residual chlorine concentrations (0.25, 0.5, 0.75, 1, 2, 3 to 5 mg lm 1) and temperatures (30°C to 45°C). The effect of shell size (=age) on C. madrasensis mortality in the presence of chlorine and taking into account temperature was significant, with the largest size group oysters showing highest resistance. At 1 mg lm 1 residual chlorine, the 13 mm and 64 mm size group oysters took 504 h (21 d) and 744 h (31 d), respectively to reach 100% mortality. At 39°C, the 13 mm size group oysters took 218 min to reach 100% mortality, whereas the 64 mm size group oysters took 325 min. The oxygen consumption and filtration rate of C. madrasensis showed progressive reduction with increasing residual chlorine concentrations. However, the filtration rate and oxygen consumption responses of C. madrasensis were not significantly different between 30°C (control) and 37.5°C. There was a sharp decrease in the filtration rate and oxygen consumption at 38.5°C. A comparison of the present mortality data with previous reports on other bivalves suggests that the chlorine tolerance of C. madrasensis lies in between that of Perna viridis and Perna perna, while its temperature tolerance is significantly higher than that of the other two bivalve species. However, in power station heat exchangers, where simultaneous chlorine and thermal stresses are existent, C. madrasensis may have an edge over other common foulants, because of its high temperature tolerance.  相似文献   
35.
Understanding the dynamics of open marine populations is inherently complex, and this complexity has led to decades of debate regarding the relative importance of pre- versus post-settlement processes in structuring these populations. Movement between patches may be an important modifier of patterns established at settlement, yet local immigration and emigration have received less attention than other demographic rates. I examined loss rates from tagged populations of juvenile wrasses (yellowhead wrasse Halichoeres garnoti and bluehead wrasse Thalassoma bifasciatum) at two sites in the Bahamas. Assuming that all losses were due solely to mortality would have significantly underestimated survivorship of yellowhead wrasse by 29% and bluehead wrasse by 14%. On average, per capita mortality and emigration rates were higher for yellowhead than bluehead wrasse, but neither demographic rate differed between sites for either species. With respect to within-species density, bluehead wrasse mortality was density-dependent at the patch reef site, but mortality rates of yellowhead wrasse were consistently density-independent. Evaluating the effects of between-species density, yellowhead wrasse mortality increased with a decrease in bluehead wrasse density, but this effect was limited to the patch reef site. Emigration rates were not a function of either within-species or between-species density, but instead varied inversely with isolation distance. Numerous previous studies of coral-reef fish, conducted on patch reefs separated by only a few meters of sand and often using untagged fish, may have confounded losses due to emigration with those due to mortality. A better understanding of the factors affecting emigration in marine fishes is important to their effective management using spatial tools such as marine protected areas.  相似文献   
36.
IntroductionThis paper presents race-specific prostate cancer mortality rates and the corresponding disparities for the largest cities in the US over two decades.MethodsThe 50 largest cities in the US were the units of analysis. Data from two 5-year periods were analyzed: 1990–1994 and 2005–2009. Numerator data were abstracted from national death files where the cause was malignant neoplasm of prostate (prostate cancer) (ICD9 = 185 and ICD10 = C61). Population-based denominators were obtained from US Census data. To measure the racial disparity, we calculated non-Hispanic Black: non-Hispanic White rate ratios (RRs), rate differences (RDs), and corresponding confidence intervals for each 5-year period. We also calculated correlation and unadjusted regression coefficients for 11 city-level variables, such as segregation and median income, and the RDs.ResultsAt the final time point (2005–2009), the US and all 41 cities included in the analyses had a RR greater than 1 (indicating that the Black rate was higher than the White rate) (range = 1.13 in Minneapolis to 3.24 in Los Angeles), 37 of them statistically significantly so. The US and 26 of the 41 cities saw an increase in the Black:White RR between the time points. The level of disparity within a city was associated with the degree of Black segregation.ConclusionThis analysis revealed large disparities in Black:White prostate cancer mortality in the US and many of its largest cities over the past two decades. The data show considerable variation in the degree of disparity across cities, even among cities within the same state. This type of specific city-level data can be used to motivate public health professionals, government officials, cancer control agencies, and community-based organizations in cities with large or increasing disparities to demand more resources, focus research efforts, and implement effective policy and programmatic changes in order to combat this highly prevalent condition.  相似文献   
37.
Biscuits are flour-based products,which areconsumed by majority of people,both old and young,throughout the world and most especially by children,teenagers and mid-adults(Majumder,1970).It can beserved as a desert or snacks and as a breakfast foodwhentaken with beverages.Its ready-to-serve state andlong shelf life contribute to its acceptability by themasses.Wheat as humanfoodis used principallyintheformof flour for baked products such as bread,bis-cuits,pastries and crackers(Kent,1983).In th…  相似文献   
38.
Synopsis The effects of constant and diurnally fluctuating levels of dissolved oxygen on the growth of young-of-the-year winter flounder,Pseudopleuronectes americanus, were examined under controlled laboratory conditions. Fish were exposed for either 10 or 11 weeks to constant levels of 6.7 (high) and 2.2 (low) mg l–1, and a diurnal fluctuation, ranging from 2.5 to 6.4 mg 02l–1. Growth rates, calculated for both standard length and weight, for fish exposed to low and diurnally fluctuating levels were significantly reduced (p < 0.001) as compared to those for fish exposed to the high level. Growth rates of fish exposed to the high level were over twice those of fish held under low oxygen conditions. Under fluctuating conditions, fish grew at intermediate rates. Following these exposures, all fish were subsequently held at 7.2 mg Oz l–1 for five weeks. Growth rates increased over two and a half times for fish previously exposed to the low oxygen level and were significantly (p < 0.001) higher than for the other two groups.  相似文献   
39.
在澳大利亚新南威尔士南部沿海,作者搜集了一个池塘繁殖的斑索蟾(Crinia signifera)的种群统计资料。通过捕捉进出池塘的1 612只个体,获得种群大小、结构、生长率、性成熟时的大小和年龄、死亡率及寿命资料。迁移高峰从6月持续到11月,蛙的最高、最低遇见数量分别出现在春季和秋季。但第2年,该池塘蛙的数量明显减少,可能是由于补充到种群中的幼体数量很少的缘故。6个月后个体的重捕率很低;但距第一次捕获18个月以后,仍有个别个体再次被捕获。性成熟时,雌性比雄性的身体大一些。生长曲线显示,雌性比雄性的生长更快,所以更早地达到性成熟。研究种群的数量、结构和死亡率趋势等与已知的其它Crinia signifera种群基本一致。但研究种群迁移活动的高峰出现较晚,并且夏季的活动水平明显很高。这种长的活动时间可能会导致存活率的下降,同时有利于选择迅速性成熟的雌性[动物学报51 (3) : 393 -400 , 2005]。  相似文献   
40.
We investigated the in vitro influence of humic substances (HS) extracted from de-inking paper sludge compost on the inhibition of Pythium ultimum by two compost bacteria, Rhizobium radiobacter (Agrobacterium radiobacter) and Pseudomonas aeruginosa. When low concentrations (5 or 50 mg l(-1)) of HS were added to the culture medium, fungal inhibition by R. radiobacter significantly increased (P<0.01) by 2-3%. In contrast, these low levels of HS had no effect on P. ultimum inhibition by P. aeruginosa. The Fe, chelated by HS, was in part responsible for the decrease of P. ultimum inhibition by the bacteria when increasing amounts of HS were added in the culture medium. The addition of 500 mg l(-1) of humic acids isolated from de-inking paper sludge compost or from fossil origin completely eliminated the inhibition of P. ultimum by R. radiobacter. This Fe effect also stimulated growth of R. radiobacter and reduced its siderophore production in a minimal medium supplemented with HS as sole source of Fe. The results showed that HS influence microbial antagonism when added to a culture medium. However, this effect varies with different factors such as the type of bacteria, concentration of HS, molecular weight and Fe content.  相似文献   
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