The coming of age of the origin of species     

Huxley TH 《Science (New York, N.Y.)》1880,1(1):15-7, 20

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Agroforestry education and training: a contemporary view     

J. P. Lassoie  P. A. Huxley  L. E. Buck 《Agroforestry Systems》1994,28(1):5-19

Most of the existing agroforestry courses have arisen opportunistically and tend to be based on the form that agroforestry takes, rather than on the way agroforestry practices function. Yet agroforestry research is beginning to supply ideas and information about the core issues (e.g., how woody and non-woody intercrops behave in terms of environmental resource capture, and how this can be influenced by the biology of the plant components and management). Similarly, recent socioeconomic research on agroforestry issues reveals dynamic systems of resource access, use, and control at various levels of human organization over time. It is true also that, because they were undertaken with different objectives in mind, the concepts derived from many decades of research in ecology, agriculture, and forestry still need to be reshaped for agroforestry situations. Likewise, socioeconomic content needs to move towards teaching the dynamics of decision-making, innovation, and change rather than describing static situations. This reshaping process itself offers exciting possibilities for educators who, thereby, could influence the course of research.These issues are briefly discussed in relation to the integration and development of research and teaching, and the needs of students and agroforestry professionals for educational and training courses. A draft proposal for the future of agroforestry at Cornell University is also outlined as a model for implementing such an approach.  相似文献   

Application of an ELISA Milk Pregnancy Test in Beef Cows          下载免费PDF全文

JN Roberts  TM Byrem  DL Grooms 《Reproduction in domestic animals》2015,50(4):651-658

Pregnancy‐associated glycoproteins (PAG) are secreted by the binucleate giant cells of the ruminant placenta and enter maternal circulation at the time of placental attachment. The IDEXX Milk Pregnancy Test (IDEXX, Westbrook, ME) detects a subset of PAG in milk. Although designed as a management tool for dairy cows, there is potential for using the milk PAG test in beef cows. Our objective was to compare the performance of the milk PAG ELISA with a gold standard method for pregnancy diagnosis and determine the agreement between milk and serum PAG analysis in lactating beef cows. Angus and Angus‐crossed cows (n = 332) from two Michigan beef herds were enrolled in this study. Cows were subjected either to timed artificial insemination followed by exposure to a bull or exclusively exposed to a bull. The bulls and cows were separated 30 days prior to examination. Serum and milk samples were collected and submitted within 24 h of collection to a commercial laboratory for PAG analysis using the IDEXX Milk Pregnancy Assay (milk) and the IDEXX Bovine Pregnancy Assay (serum). Concurrently with milk and serum collection, each cow was examined transrectally by palpation or ultrasonography. When compared to transrectal examination, the performance (and 95% confidence intervals) of the milk PAG ELISA was sensitivity of 99.7% (99.0–100.0%) and specificity of 80.8% (65.6–95.9%). The lower specificity is likely due to the low prevalence (9.9%) of open cows (n = 30) in the herds examined. Of the 332 cows examined, 1.8% (n = 6) were classified as rechecks using the milk PAG ELISA. Results of the milk and serum PAG ELISA were in high agreement (kappa coefficient = 0.91). The milk PAG ELISA was accurate in predicting pregnancy status using milk collected from beef cattle between days 37 and 125 post‐insemination and may be useful for aiding management decisions in beef herds.  相似文献   

Mass-independent oxygen isotope fractionation in atmospheric CO as a result of the reaction CO + OH     

T Rockmann  CAM Brenninkmeijer  G Saueressig  P Bergamaschi  JN Crowley  H Fischer  PJ Crutzen 《Science (New York, N.Y.)》1998,281(5376):544-546

Atmospheric carbon monoxide (CO) exhibits mass-independent fractionation in the oxygen isotopes. An 17O excess up to 7.5 per mil was observed in summer at high northern latitudes. The major source of this puzzling fractionation in this important trace gas is its dominant atmospheric removal reaction, CO + OH --> CO2 + H, in which the surviving CO gains excess 17O. The occurrence of mass-independent fractionation in the reaction of CO with OH raises fundamental questions about kinetic processes. At the same time the effect is a useful marker for the degree to which CO in the atmosphere has been reacting with OH.  相似文献   

Protactinium-231 and thorium-230 abundances and high scavenging rates in the western arctic ocean     

HN Edmonds  SB Moran  JA Hoff  JN Smith  RL Edwards 《Science (New York, N.Y.)》1998,280(5362):405-407

The Canadian Basin of the Arctic Ocean, largely ice covered and isolated from deep contact with the more dynamic Eurasian Basin by the Lomonosov Ridge, has historically been considered an area of low productivity and particle flux and sluggish circulation. High-sensitivity mass-spectrometric measurements of the naturally occurring radionuclides protactinium-231 and thorium-230 in the deep Canada Basin and on the adjacent shelf indicate high particle fluxes and scavenging rates in this region. The thorium-232 data suggest that offshore advection of particulate material from the shelves contributes to scavenging of reactive materials in areas of permanent ice cover.  相似文献   

Macrozamia toxicosis in a dog     

JN MILLS  MJ LAWLEY  J. THOMAS 《Australian veterinary journal》1996,73(2):69-72

A case of Macrozamia riedlei seed poisoning is described in a young Dachshund. Vomiting and depression commenced within 6 h of ingestion; other signs that developed included severe hepatopathy, jaundice, abdominal pain that was unresponsive to analgesics, severe gastro-intestinal haemorrhage and thrombocytopenia as well as crystalluria and marrow dyserythropoiesis. The dog was euthanased 6 days after ingestion of the seeds.  相似文献   

THE GREAT CRESTED GREBE AND THE IDEA OF SECONDARY SEXUAL CHARACTERS     

Huxley JS 《Science (New York, N.Y.)》1912,36(931):601-602

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THE PROPOSED FISHERIES BOARD OF GREAT BRITAIN     

Huxley TH 《Science (New York, N.Y.)》1886,7(167):344-346

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Assessment of Levels and Potential Health Risk of Heavy Metals in Water and Selected Fish Species from the Benue-Niger River Confluence,Lokoja, Nigeria     

NR. Ekere  NM Yakubu  JN Ihedioha 《Journal Of Aquatic Food Product Technology》2018,27(7):772-782

The concentrations of cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), zinc (Zn), and iron (Fe) in water and selected fish species (Oreochromis nilzinc (oticus and Clarias gariepinus) from Benue-Niger River Confluence, Nigeria were investigated. The water and fish sample digests were quantified using an atomic absorption spectrophotometer. The study aimed to assess any possible human health risk associated with water and fish consumption from the selected geographical area. The concentration of the metals in the surface water ranged from 0.007 to 0.039, 0.106 to 0.240, 0.092 to 0.0164, 0.682 to 0.878, 0.058 to 0.309, and 0.136 to 1.645 mg/L for Cd, Cr, Cu, Fe, Pb, and Zn, respectively, while the concentrations of the metals, Cd, Pb, Cr, Cu, Zn, and Fe in these fish species ranged from 0.034 to 0.679, 0.500 to 1.75, 0.152 to 0.351, 0.36 to 1.01, 5.32 to 7.41, and 4.25 to 9.17 mg/kg, respectively. Cd, Cr, and Pb levels in fish were higher than the provisional tolerable weekly intake of 7, 1.5, and 25 μg/kg bw, respectively, according to the World Health Organization. Dry season values of the metals in water samples were higher, and sharptooth catfish had higher amounts of the metals. The hazard quotient (HQ) for Cd indicated a possible potential health concern with fish consumption from this area.  相似文献   

Laryngeal hemiplegia in a heifer     

Bushby VE  Woodford NS  Little DR  Huxley JN 《The Veterinary record》2004,155(22):715

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