Van der waals picture of liquids, solids, and phase transformations     

Chandler D  Weeks JD  Andersen HC 《Science (New York, N.Y.)》1983,220(4599):787-794

The van der Waals picture focuses on the differing roles of the strong short-ranged repulsive intermolecular forces and the longer ranged attractions in determining the structure and dynamics of dense fluids and solids. According to this physical picture, the attractive interactions help fix the volume of the system, but the arrangements and motions of molecules within that volume are determined primarily by the local packing and steric effects produced by the repulsive forces. This very useful approach, its limitations, and its successful application to a wide variety of static and dynamic phenomena in condensed matter systems are reviewed.  相似文献   

A rapid shift in a classic clinal pattern in Drosophila reflecting climate change     

Umina PA  Weeks AR  Kearney MR  McKechnie SW  Hoffmann AA 《Science (New York, N.Y.)》2005,308(5722):691-693

Geographical clines in genetic polymorphisms are widely used as evidence of climatic selection and are expected to shift with climate change. We show that the classic latitudinal cline in the alcohol dehydrogenase polymorphism of Drosophila melanogaster has shifted over 20 years in eastern coastal Australia. Southern high-latitude populations now have the genetic constitution of more northerly populations, equivalent to a shift of 4 degrees in latitude. A similar shift was detected for a genetically independent inversion polymorphism, whereas two other linked polymorphisms exhibiting weaker clinal patterns have remained relatively stable. These genetic changes are likely to reflect increasingly warmer and drier conditions and may serve as sensitive biomarkers for climate change.  相似文献   

Magnetic resonance properties of some lunar material     

Weeks RA  Chatelain A  Kolopus JL  Kline D  Castle JG 《Science (New York, N.Y.)》1970,167(3918):704-707

Paramagnetic resonance spectra of Apollo 11 fines and rocks were measured at 9 and 35 gigahertz and at 4 degrees , 80 degrees , and 300 degrees K. At both frequencies the material has an intense absorption at g = 2, with a line width of approximately 950 gauss. Fe ions with strong exchange interactions produce this resonance. A comparison of the resonance absorption due to Fe(3+) showed that the energy of the crystal field interaction was approximately 0.1 per centimeter. Mn(2+) was identified in several samples, and an absorption at g = 1.89 was tentatively attributed to Ti(3+). The nuclear magnetic resonance spectra of (27)Al had a distribution of asymmetry parameters eta ranging from 0.25 to 0.75 and had nuclear quadrupole coupling constants e(2)qQ/h of approximately 3 megahertz.  相似文献   

Experimental infection studies demonstrate the high susceptibility of the salmonid, lake herring, Coregonus artedi (Le Sueur), to the Great Lakes strain of viral haemorrhagic septicaemia virus (genotype IVb)     

Weeks C  Kim R  Wolgamod M  Whelan G  Faisal M 《Journal of fish diseases》2011,34(11):887-891

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Nitrate Toxicity to Five Species of Marine Fish   总被引：2，自引：0，他引：2  

Richard H.  Pierce Jason M.  Weeks  James M.  Prappas 《Journal of the World Aquaculture Society》1993,24(1):105-107

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Feasibility of using foam fractionation for the removal of dissolved and suspended solids from fish culture water   总被引：4，自引：0，他引：4  

N.C. Weeks  M.B. Timmons  S. Chen 《Aquacultural Engineering》1992,11(4):251-265

The results of an experimental study on the feasibility of foam fractionation to remove suspended and dissolved solids from fish culture water are presented. Foam fractionation was found to concentrate volatile solids (VS), total Kjeldahl nitrogen (TKN), and total suspended solids (TSS) in the foam condensate. Foam fractionation did not concentrate fixed solids (FS). Air flow rate and overflow height were found to be important operational factors in determining condensate concentration, condensate production and removal rates of VS. Predictive regression equations are presented to predict the performance of a typically configured foam fractionation device. Measurements of TKN and TSS in the foam condensate and fish culture water were well correlated with VS, indicating that VS measurements can be used to predict concentrations and removal rates of both TKN and TSS from fish culture waters that are similar to those analyzed.  相似文献   

Dicamba resistance: enlarging and preserving biotechnology-based weed management strategies   总被引：1，自引：0，他引：1  

Behrens MR  Mutlu N  Chakraborty S  Dumitru R  Jiang WZ  Lavallee BJ  Herman PL  Clemente TE  Weeks DP 《Science (New York, N.Y.)》2007,316(5828):1185-1188

The advent of biotechnology-derived, herbicide-resistant crops has revolutionized farming practices in many countries. Facile, highly effective, environmentally sound, and profitable weed control methods have been rapidly adopted by crop producers who value the benefits associated with biotechnology-derived weed management traits. But a rapid rise in the populations of several troublesome weeds that are tolerant or resistant to herbicides currently used in conjunction with herbicide-resistant crops may signify that the useful lifetime of these economically important weed management traits will be cut short. We describe the development of soybean and other broadleaf plant species resistant to dicamba, a widely used, inexpensive, and environmentally safe herbicide. The dicamba resistance technology will augment current herbicide resistance technologies and extend their effective lifetime. Attributes of both nuclear- and chloroplast-encoded dicamba resistance genes that affect the potency and expected durability of the herbicide resistance trait are examined.  相似文献   

Retrospective study of 108 foals with septic osteomyelitis     

KM Neil  JE Axon  AP Begg  PG Todhunter  PL Adams  AE Fine  JP Caron  AR Adkins 《Australian veterinary journal》2010,88(1-2):4-12

Objective   To determine the clinical characteristics, short-term outcome and future athletic performance of foals with septic osteomyelitis.
Design   Retrospective clinical study of 108 Thoroughbred foals with radiographic evidence of bone infection that were presented at the Scone Veterinary Hospital between August 1995 and December 2001. Medical records were reviewed and information concerning signalment, the clinical, laboratory and radiographic findings, treatment and outcome was obtained. Racing records were obtained and evaluated for surviving foals that had reached racing age.
Results   Mean age of foals at initial evaluation was 39 days (range 1–180 days); 21 foals had multiple radiographic bone lesions (19.4%), and 76 had concurrent septic arthritis (70.4%). The most frequently affected bones were the femur, tibia and distal phalanx. In total, 87 foals were discharged from the hospital (80.6%), 79 survived long-term to reach racing age and 52 raced (65.8%). Overall, 48% (52/108) of the foals treated for osteomyelitis raced. Foals less than 30 days of age at the time of diagnosis, critically ill foals and those with multiple bones or joints affected were significantly less likely to be discharged from hospital. Multiple septic joints, but not multiple bone involvement, had an unfavourable prognosis for racing.
Conclusions   The prognosis for survival of foals with septic osteomyelitis or osteitis is favourable. Multiple bone or joint involvement is an important short-term prognostic indicator; however, the involvement of multiple joints, but not multiple infected bones, is associated with an unfavourable prognosis for racing.  相似文献   

Discovery of metabolic resistance to neonicotinoids in green peach aphids (Myzus persicae) in Australia          下载免费PDF全文

Siobhan C de Little  Owain Edwards  Anthony R van Rooyen  Andrew Weeks  Paul A Umina 《Pest management science》2017,73(8):1611-1617

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Monochorial diamniotic dizygotic twins in a German Shepherd Dog: A case report          下载免费PDF全文

C Urhausen  K Wolf  A Beineke  C Dierks  M Schmicke  A Einspanier  AR Günzel‐Apel 《Reproduction in domestic animals》2017,52(1):140-143

Case report: A 6.5‐year‐old clinically healthy German Shepherd Dog with regular oestrous cycles of 6 months was presented for pregnancy diagnosis on day 38 after ovulation (p.ov.). Ultrasonography revealed three individual placental sites in progressed resorption and two vital adequately developed foetuses sharing a joint placenta. On days 41 and 48 p.ov., sonographic signs indicated normal development of both foetuses, but on day 52 p.ov., both foetuses were found to be dead. A caesarean section was performed the same day. Examination of the removed uterus confirmed the diagnosis of a “twin” pregnancy with two foetuses sharing the same placental site but separate amniotic membranes. One foetus showed generalized oedema (anasarca). Bacterial culture of swabs taken from inside the placental cavity was negative. At histological examination of the uterus, no signs of inflammation were found. Serum relaxin concentrations (day 38, 41, 48 and 52. p.ov.) were consistent with those of bitches with normal pregnancies. Cytogenetic analysis of the two foetuses revealed dizygotic twins, one male and one female according to SRY‐PCR. By genotyping 17 high‐polymorphic canine microsatellites, it could be demonstrated that the two foetuses developed from two different oocytes.  相似文献