Dredging fundamentally reshapes the ecological significance of 3D terrain features for fish in estuarine seascapes

Landscape Ecology - Landscape modification alters the condition of ecosystems and the structure of terrain, with widespread impacts on biodiversity and ecosystem functioning. Seafloor dredging...     

带拉杆的U形壳槽槽身横向内力计算有关问题的分析

在U形壳槽横向内力计算中,若不考虑槽底局部加厚对Φ=90°截面内力的影响,则计算所得的该截面弯矩绝对值偏小.温度变化对截面内力的影响较大,特别是温降引起多数截面的弯矩增加,而轴向力减少;温升引起Φ=90°截面弯矩与轴向拉力均增加,再考虑槽底局部加厚的影响,弯矩值还要增加.槽底局部加厚与温度变化的作用均不能忽略不计,否则,内力计算成果值会偏于不安全.用结构力学方法,推导出二者对内力影响的计算公式,并附有应用的算例.     

Effect of dietary crude-protein type on fertilization and embryo quality in dairy cattle

An experiment was conducted to determine whether balancing dietary crude protein for optimal rumen degradability would improve fertilization rate and quality of ova in lactating dairy cows. Thirty-eight Holstein cows in early lactation were fed 1 of 2 diets formulated to be isocaloric and isonitrogenous, containing 16% crude protein. Diet 1 contained 73% rumen degradable intake protein, whereas diet 2 contained 64% rumen degradable intake protein. The cows were induced to superovulate and were inseminated, and ova were recovered nonsurgically on postbreeding day 7. Ova were counted and classified as fertilized or unfertilized. Fertilized ova were scored as excellent, good, fair, poor, or degenerate. Unfertilized ova and poor and degenerate embryos were considered to be nontransferable ova and excellent, good, and fair embryos were considered to be transferable ova. There were no differences for mean number of fertilized, unfertilized, transferable, or nontransferable ova recovered from cows fed the 2 diets (P greater than 0.10). Mean percentage of fertilized ova recovered from cows was greater (P less than 0.05) in those fed diet 2, compared with diet 1. Mean percentage of transferable ova recovered from cows tended to be greater (P = 0.06) in those fed diet 2, compared with diet 1. More cows failed to yield transferable ova (P less than 0.05) when fed diet 1, compared with diet 2. Fertilization failure or early degeneration of embryos may occur in cows fed excess rumen degradable protein.     

Prognostic factors for tumor remission and survival in dogs after surgery for primary lung tumor: 76 cases (1975-1985)

The association of various prognostic factors with remission and survival after the excision of lung tumors was evaluated in 76 dogs. Overall, the median survival time of treated dogs was 120 days; 72% had tumor that underwent remission (median duration of remission, 120 days). Dogs with tumors that underwent remission had significantly (P = 0.001) increased survival time (median, 330 days vs 28 days for dogs with tumors that did not undergo remission). The finding of normal-sized lymph nodes at the time of therapeutic thoracotomy was significantly (P = 0.001) correlated with increased remission probability (85.4% remission rate vs 43.6% in dogs with large lymph nodes). Use of various diagnostic methods to find normal regional lymph nodes before surgery indicated that such finding was significantly (P less than or equal to 0.01) correlated with increased remission duration (median remission duration, 365 days, vs 60 days for tumors in dogs with large lymph nodes), and the finding of normal lymph nodes at the time of surgery was significantly (P less than or equal to 0.01) correlated with increased survival time (median, 345 days, vs 60 days for dogs with large lymph nodes).     

Prevention of Toxoplasma gondii abortion in goats by vaccination with oocysts of Hammondia hammondi

Nineteen does (female goats) were dosed with 500,000 oocytes of Hammondia hammondi prior to breeding. At about 90 days of gestation these, and 18 uninoculated does were challenged with 25,000 Toxoplasma gondii oocysts. The 19 H. hammondi--inoculated does produced 26 live and one dead kid (newborn goat). The 18 does not given H. hammondi produced 12 live and 19 dead kids. However, examination of all of the kids by isolation of T. gondii in mice, serology and histology revealed that they were all infected with T. gondii. Thus, while H. hammondi "vaccination" is protective against the deleterious effects of T. gondii on pregnant does, perhaps by reducing the severity of placental lesions, it does not prevent foetal infection.