Quebrada jaguay: early south american maritime adaptations     

DH Sandweiss  H McInnis  RL Burger  A Cano  B Ojeda  R Paredes  MC Sandweiss  MD Glascock 《Science (New York, N.Y.)》1998,281(5384):1830-1832

Excavations at Quebrada Jaguay 280 (QJ-280) (16 degrees30'S) in south coastal Peru demonstrated that Paleoindian-age people of the Terminal Pleistocene (about 11,100 to 10,000 carbon-14 years before the present or about 13,000 to 11,000 calibrated years before the present) in South America relied on marine resources while resident on the coast, which extends the South American record of maritime exploitation by a millennium. This site supports recent evidence that Paleoindian-age people had diverse subsistence systems. The presence of obsidian at QJ-280 shows that the inhabitants had contact with the adjacent Andean highlands during the Terminal Pleistocene.  相似文献   

Toxicity studies in mice of common spices,Cinnamomum zeylanicum bark and Piper longum fruits     

Shah  A.H.  Al-Shareef  A.H.  Ageel  A.M.  Qureshi  S. 《Plant foods for human nutrition (Dordrecht, Netherlands)》1998,52(3):231-239

Acute (24 hours) and chronic (90 days) oral toxicity studies on the ethanolic extracts of common spices Cinnamomum zeylanicum Nees bark and Piper longum L. fruits were carried out in mice. Acute dosages were 0.5, 1.0 and 3 g/kg while the chronic dosage was 100 mg/kg/day. All external morphological, hematological and spermatogenic changes, in addition to body weight and vital organ weights, were recorded. The extracts of both the plants caused no significant acute or chronic mortality compared to the control during this study. During chronic treatment there was no significant change in the pre- and post treatment body weight of the test animals while the weight gain in the control group was significant. C. zeylanicum treatment caused reduction in liver weight while P. longum caused a significant increase in the weight of the lungs and spleen of the treated animals compared to the control. Hematological studies revealed a significant fall in hemoglobin level of C. zeylanicum treated animals. Both of the extracts induced a significant increase in reproductive organ weights, sperm motility, sperm count and failed to illicit any spermatotoxic effect.  相似文献   

Identification and characterization of important sterile and maintainer lines from various genotypes for advanced breeding programmes of onion (Allium cepa)     

Rafiq Ahmad  Mahmood-ul- Hassan  Ghanan B. Akhtar  Sadia Saeed  Sabaz A. Khan  Muhammad Kausar Nawaz Shah  Nadeem Khan 《Plant Breeding》2020,139(5):988-995

Onion is one of the major vegetable crops in terms of production as well as consumption. In the current research, available onion genetic stock was evaluated to identify male-sterile lines and produce high-yielding F₁ hybrids for future breeding programmes. A mitochondrial DNA-based marker was mapped and correlated with phenotypic traits to isolate male-sterile plants. Based on the floral and pollen structure, nine putative male-sterile lines were identified. On the other hand, for nuclear marker identification at Ms locus, two sets of primers were used, one for Ms dominant allele and another for sterile and maintainer plants. Results revealed that 70% of open pollinated varieties (OPVs) possess plants with sterile cytoplasm coupled with genetic sterility at Ms locus, called sterile “A” line. Approximately 20% of plants in some genotypes were identified with normal (N) cytoplasm having recessive fertility gene at Ms locus, called maintainer “B” line. Based on the present findings, “A”, “B” and “R” (restorer line), future F₁ hybrid seed production systems in onion is discussed.  相似文献   

Nitrogen status and transformations in coal mine spoil     

S. S. H. Shah  T. H. Flowers  I. D. Pulford 《Land Degradation \u0026amp; Development》1990,2(3):201-207

A detailed study was undertaken to measure mineral nitrogen status, mineralization rate of carbon and nitrogen, nitrification rate and fixation of added ammonium on 90 samples of coal mine spoils collected throughout Central Scotland. The inorganic nitrogen status of the spoils was very low (mean 3.4 mg N kg⁻¹). The rate of carbon dioxide evolution was high compared to the low rate of nitrogen mineralized, resulting in a mean mineralized C:N ratio of 178. Nitrification of added ammonium was measurable on only half of the samples studied. Spoil with pH < 4.8 showed no nitrification of added ammonium. However, on some sites above this pH no net nitrification was measured, which suggested the absence of nitrifying bacteria. A considerable amount of applied ammonium nitrogen was lost either as a result of ammonium fixation by clay minerals, or assimilation by the heterotrophic population due to the wide mineralizable C:N ratio.  相似文献   

Dietary Protein Requirements of Juvenile Black Sea Bass,Centropristis striata     

Md. Shah Alam  Wade O. Watanabe  Patrick M. Carroll 《Journal of the World Aquaculture Society》2008,39(5):656-663

A feeding trial was conducted in a recirculating system to determine the dietary protein requirement for juvenile black sea bass. Six isocaloric diets were formulated to contain varying levels of crude protein (CP) ranging from 36 to 56% (36, 40, 44, 48, 52, and 56%) by substituting a mixture of carbohydrates and lipid for fish meal. The feeding experiment was carried out in 18‐75 L aquaria stocked at a density of 15 juveniles (initial average weight 6.7 g) per tank. Fish were fed test diets in triplicate tanks to apparent satiation twice a day for 8 wk. Whole‐body proximate composition was analyzed after the feeding trial. After the feeding trial, weight gain and specific growth rate of fish fed the 44% CP diet were not significantly different from those fed the 48, 52, and 56% CP diets, but were significantly higher (P < 0.05) than those fed the 36 and 40% CP diets. Feed conversion efficiency and protein efficiency ratio were significantly affected by dietary protein level. The dietary requirement of protein for maximum growth of black sea bass juveniles, estimated using broken‐line regression analysis on weight gain, was 45.3% and maximum weight gain occurred at 52.6% based on polynomial regression analysis.  相似文献