Optical studies of individual InAs quantum dots in GaAs: few-particle effects

Optical emission from individual strained indium arsenide (InAs) islands buried in gallium arsenide (GaAs) was studied. At low excitation power density, the spectra from these quantum dots consist of a single line. At higher excitation power density, additional emission lines appeared at both higher and lower energies, separated from the main line by about 1 millielectron volt. At even higher excitation power density, this set of lines was replaced by a broad emission peaking below the original line. The splittings were an order of magnitude smaller than the lowest single-electron or single-hole excited state energies, indicating that the fine structure results from few-particle interactions in the dot. Calculations of few-particle effects give splittings of the observed magnitude.     

Morpho‐physical Recording of Bovine Conceptus (Bos indicus) and Placenta from Days 20 to 70 of Pregnancy

The study is based on 141 pregnant Bos indicus cows, from days 20 to 70 post‐insemination. First, special attention was given to the macroscopically observable phenomena of attachment of the conceptus to the uterus, i.e. the implantation, from about days 20 to 30 post‐insemination up to day 70, and placentome development by growth, vascularization and increase in the number of cotyledons opposite to the endometrial caruncles. Secondly, as for the conceptuses, semiquantitative, statistical analyses were performed of the lengths of chorio‐allantois, amnion and yolk sac; and the different parts of the centre and two extremes of the yolk sacs were also analysed. Thirdly, the embryos/foetuses corresponding to their membranes were measured by their greatest length and by weight, and described by the appearance of external developmental phenomena during the investigated period like neurulation, somites, branchial arcs, brain vesicles, limb buds, C‐form, pigmented eye and facial grooves. In conclusion, all the data collected in this study from days 20 to 70 of bovine pregnancy were compared extensively with corresponding data of the literature. This resulted in an ‘embryo/foetal age‐scale’, which has extended the data in the literature by covering the first 8 to 70 days of pregnancy. This age‐scale of early bovine intrauterine development provides model for studies, even when using slaughtered cows without distinct knowledge of insemination or fertilization time, through macroscopic techniques. This distinctly facilitates research into the cow, which is now being widely used as ‘an experimental animal’ for testing new techniques of reproduction like in vitro fertilization, embryo transfer and cloning.     

Largemouth bass predators reduce growth,feeding and movement in juvenile channel catfish

Fine ML, Mayo MS, Newton SH, Sismour EN. Largemouth bass predators reduce growth, feeding and movement in juvenile channel catfish. Ecology of Freshwater Fish 2011: 20: 114–119. © 2010 John Wiley & Sons A/S Abstract – Animals utilise sensory cues to make decisions that will decrease their vulnerability to predation. With a well‐developed olfactory system and taste buds located inside the mouth and on the external body surface, catfishes are excellent subjects to investigate nonconsumptive predator effects. Juvenile channel catfish Ictalurus punctatus are often eaten by largemouth bass Micropterus salmoides, and we tested the hypothesis that largemouth bass fed catfish would adversely affect foraging and growth in channel catfish. Groups of catfish were placed in tanks partitioned by a mesh screen: experimental tanks had a largemouth bass on the other half of the tank, and control tanks had an empty chamber. Experimental catfish exhibited a long‐term decrease in spontaneous motion, feeding and growth. Feeding catfish to the bass caused the experimental catfish to freeze after a multi‐second latency suggesting transport of an alarm cue. Thus, there were long‐term effects from the continuous presence of the bass and additional short‐term cues from the bass consuming a catfish.     

Anthropogenic and meteorological factors influence vector abundance and prevalence of bluetongue virus infection of dairy cattle in California

Bluetongue is an economically important arboviral disease of ruminants that is transmitted by hematophagous Culicoides midges. In light of dramatic recent changes in the global distribution of bluetongue virus (BTV), the goals of this study were to re-evaluate the prevalence of BTV infection of cattle and abundance of Culicoides midges on individual dairy farms in California. A serosurvey of adult dairy cattle confirmed that BTV infection is prevalent throughout much of the state, although the coastal northwestern region remains free of infection and prevalence varies markedly among farms in the remainder of the state. Intensive sampling for one year of 4 farms in the northern Central Valley of California showed that the abundance of Culicoides midges was markedly different and coincided with the prevalence of BTV infection of sentinel cattle on each farm. Mean maximum and minimum temperatures and other meteorological parameters were similar on all 4 farms, thus we speculate that particular management practices were responsible for both the increased midge abundance and prevalence of BTV infection of cattle at individual farms. Specifically, it is concluded that variation in vector abundance at individual farms most likely is the result of waste-water lagoon and irrigation management practices, leading to higher BTV infection rates among livestock held on farms with more waste-water lagoons and greater acreage of land for waste-water irrigation.     

Anesthesia and pain management in Russia

There was only limited emphasis on anesthesia and pain management in veterinary colleges in Russia until the last ten years. There is now great interest in improvement by Russia practitioners. This effort is hampered by the lack of approved and available medications and limited instructions. At this time, the small animal practitioners have tranquilizers, alpha₂ agonists local anesthetics and NSAID's for their use. Propofol is available through pharmacies and efforts are being made for veterinarians to use ketamine. Only a few practices have inhalant anesthetic units and halothane. During a recent lecture tour of Russia, general clinical principles and specific anesthetic and pain management protocols were taught. The audience, primarily young and progressive veterinarians, actively participated and showed great desire to practice quality anesthesia and pain management for their patients. Teaching young veterinarians how to manage their cases without the availability of opioids, ketamine advanced anesthetic equipment and monitors was indeed challenging. Protocols for perioperative management consisting of medetomidine with or without local anesthesia followed by carprofen for post-operative pain is an improvement. We sometimes spend so much time discussing which of many drug combinations we will use but seldom consider what we would do if we were practicing our specialty in parts of the world where we would have to modify dosages and combinations to achieve humane care with few drug choices.     

Progressive tetraparesis and laryngeal paralysis in a young Rottweiler with neuronal vacuolation and axonal degeneration: an Australian case

A 5-month-old female Rottweiler dog was diagnosed to have a neurodegenerative disease that has been recently report ed in Rottweilers from North America and Europe. The dog was presented with progressive signs of ataxia, tetraparesis and inspiratory stridor. The clinical investigation included analysis of CSF, radiography, myelography and electrophysiolog-ical testing. No evidence of vertebral malformation or inflammatory CNS disease was identified. Bilateral laryngeal paraly sis was identified in the lightly anaesthetised dog. Electromyography showed abnormal spontaneous activity from the intrin sic musculature of the larynx. At necropsy there were no gross abnormalities of the nervous system but there was atrophy of the dorsal cricoarytenoid muscles of the larynx. There were widespread histological abnormalities throughout the ner vous system including neuronal vacuolation, spongiform changes in the neuropil and axonal degeneration which was most prominent in the spinal cord. These clinical and pathological findings are consistent with the diagnosis of a new neurode-generative disease reported from North America and Europe. This diagnosis is of particular significance in Australia where transmissible spongiform encephalopathies have not been identified.