Characteristics of the ionization tracks and interactions of uranium-238 nuclei in emulsion     

Heckman HH  Karant YJ  Friedlander EM 《Science (New York, N.Y.)》1982,217(4565):1137-1138

The acceleration and extraction of uranium-238 nuclei by the Bevalac have been confirmed by their visual detection in nuclear research emulsion. A preliminary result for the collision mean free path for stopping uranium-238 (energy 相似文献   

Sectional notes     

J. H. Heckman  H. G. Zuckerman  C. H. Metzger  W. B. Ward  John S. Gardner  Frank W. Hussey  Ralph W. Donaldson  A. G. Tolaas  K. H. Fernow  E. V. Hardenburg  W. G. Been  Robert Schmidt  E. M. Gillig  E. B. Tussing  K. W. Lauer  K. H. Klages  Brooks D. Drain  H. L. Bailey  J. G. Milward 《American Journal of Potato Research》1935,12(7):196-204

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Sectional notes     

J. H. Heckman  H. G. Zuckerman  C. H. Metzger  B. A. Brown  E. R. Bennett  W. B. Ward  C. L. Fitch  O. H. Elmer  Jhon S. Gardner  Julan C. Miller  Frank W. Hussey  E. L. Newdick  Ralph W. Donaldson  Lionel Harris  H. O. Werner  Wm. H. Martin  E. V. Hardenburg  T. E. Odland  Robert Schmidt  Geo E. Prince  Brooks D. Drain  Harold L. Bailey  G. S. Ralston  Chase D. Gaines  J. G. Milward  John Tucker 《American Journal of Potato Research》1935,12(6):158-170

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Analysis of foods for iodine: interlaboratory study     

M M Heckman 《Journal of the Association of Official Analytical Chemists》1979,62(5):1045-1049

An accurate, reproducible method for less than or equal to 1 ppm iodine in foods is required for nutritional labeling. In order to ascertain the current status of iodine analysis in foods, 7 samples, representing different food classes, were analyzed by 8 laboratories. Six laboratories used their modifications of the Ce-As-I catalytic method preceded by alkaline dry ashing. Two laboratories used neutron activation analysis (NAA), with differing radiochemical separations. The study showed wide discrepancy in analytical results. Mean relative standard deviation for all laboratories was 77.9% between laboratories; 19.1% within-laboratories. Laboratories using NAA had only slightly better precision than did laboratories using the chemical method. The lowest level reported on the entire group of samples ranged among laboratories from 0.0089 to 0.65 ppm. Figures reported by a laboratory are, in general, consistently high or consistently low. The only differences in methodology which may possibly correlate with level of iodine obtained are the use of NAA technique and use of manual, rather than automated, colorimetry.  相似文献   

Collaborative study of a copper in feeds by atomic absorption spectrophotometry     

M Heckman 《Journal of the Association of Official Analytical Chemists》1971,54(3):666-668

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Continued freedom from blue-tongue virus infection in cattle and sheep in Western Australia south of latitude 26° S     

TM ELLIS  R. TURNOR  TT NGUYEN  U. TARNOWSKI 《Australian veterinary journal》1996,74(4):317-319

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Skill formation and the economics of investing in disadvantaged children   总被引：1，自引：0，他引：1  

Heckman JJ 《Science (New York, N.Y.)》2006,312(5782):1900-1902

This paper summarizes evidence on the effects of early environments on child, adolescent, and adult achievement. Life cycle skill formation is a dynamic process in which early inputs strongly affect the productivity of later inputs.  相似文献   

Hunting behavior of a marine mammal beneath the antarctic fast Ice   总被引：1，自引：0，他引：1  

RW Davis  LA Fuiman  TM Williams  SO Collier  WP Hagey  SB Kanatous  S Kohin  M Horning 《Science (New York, N.Y.)》1999,283(5404):993-996

The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder. Weddell seals stalked large Antarctic cod and the smaller subice fish Pagothenia borchgrevinki, often with the under-ice surface for backlighting, which implies that vision is important for hunting. They approached to within centimeters of cod without startling the fish. Seals flushed P. borchgrevinki by blowing air into subice crevices or pursued them into the platelet ice. These observations highlight the broad range of insights that are possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.  相似文献   

Outbreaks of severe myositis in cultured white sturgeon (Acipenser transmontanus L.) associated with Streptococcus iniae     

Felipe Pierezan  Khalid Shahin  Taylor I. Heckman  June Ang  Barbara A. Byrne  Esteban Soto 《Journal of fish diseases》2020,43(4):485-490

Outbreaks of an infectious disease affecting cultured white sturgeon (Acipenser transmontanus) were investigated. Clinical signs included erratic swimming, arching of the back and mortality. Necropsy findings included poorly demarcated yellow to dark-red and friable lesions in the epaxial muscle, ulcerative skin lesions and haemorrhages in the swim bladder and coelomic wall. Histological evaluation revealed areas of necrotizing and heterophilic myositis with aggregates of bacterial cocci. The lumen of blood vessels in the dermis, under ulcerated areas, and in the posterior kidney, was occluded by fibrin thrombi. Aggregates of Gram-positive cocci were observed in the muscle lesions and within the fibrin thrombi in the dermis and kidney. Genetically homogeneous Streptococcus iniae strains were recovered from affected fish from different outbreaks. The isolates shared high degree of similarity at gene locus (gyrB) with previously characterized S. iniae from cultured fish in California, confirming the emergence of this particular strain of S. iniae in US aquaculture.  相似文献   

Pulmonary Maturation in Canine Foetuses From Early Pregnancy to Parturition     

TM Sipriani  F Grandi  LCG da Silva  PC Maiorka  CI Vannucchi 《Reproduction in domestic animals》2009,44(S2):137-140

Development of the foetal respiratory system includes both pulmonary growth and maturation. In human medicine, a higher incidence of respiratory distress is reported in newborn males. This study aimed to identify different phases of canine foetal lung maturation throughout pregnancy, to determine the stage of pregnancy in which surfactant production begins and to compare pulmonary development of male and female foetuses. Pregnant bitches (34) were subjected to elective ovariohysterectomy and allocated into four groups, according to the stage of pregnancy: 30–40 days of pregnancy (n = 10), 41–50 days (n = 10), 51–60 days (n = 10) and bitches in the first stage of parturition (n = 4). Foetal lungs were histologically processed and evaluated by optical microscopy. The pseudoglandular phase was identified between the 35th day and 46th day of gestation; the onset of canalicular and saccular periods was observed, respectively, from the 48th day and 60th day of pregnancy. Lungs from foetuses at term were in the saccular phase; thus, the development into the alveolar period occurs in the neonatal period. The histological analyses revealed that respiratory tract development is centrifugal, from upper to lower airways. Therefore, it is possible to identify distinct development periods in different portions of the same organ. In conclusion, the saccular phase of lung development begins around 57 and 60 days of pregnancy, the period in which surfactant production is believed to occur. Male and female foetuses present similar pulmonary development from early pregnancy until parturition.  相似文献