Toxicity of aquatic herbicides to Daphnia magna

Accurate determination of the acute toxicities of a series of 16 aquatic herbicides to Daphnia magna reveals that several of them may present a hazard to food-chain microfauna whether the compounds are environmentally destroyed or not.     

Multiple‐line cross QTL mapping for grain yield and thousand kernel weight in triticale

Grain yield and its component trait thousand kernel weight are important traits in triticale breeding programmes. Here, we used a large mapping population of 647 doubled haploid lines derived from four families to dissect the genetic architecture underlying grain yield and thousand kernel weight by multiple‐line cross QTL mapping. We identified 3 QTL for grain yield and 13 for thousand kernel weight which cross‐validated explained 5.2% and 48.2% of the genotypic variance, respectively. Both traits showed a positive phenotypic correlation, and we found two QTL overlapping between them. Full two‐dimensional epistasis scans revealed epistatic QTL for both traits, suggesting that epistatic interactions contribute to their genetic architecture. Based on QTL identified in our results, we conclude that the potential for marker‐assisted selection is limited for grain yield but more promising for thousand kernel weight.     

Direct contact transmission of three different foot-and-mouth disease virus strains in swine demonstrates important strain-specific differences

A novel direct contact transmission model for the study of foot-and-mouth disease virus (FMDV) infection of swine was utilized to investigate transmission characteristics of three FMDV strains belonging to serotypes A, O and Asia1. Each strain demonstrated distinct transmission characteristics and required different exposure times to achieve successful contact transmission. While a 4h exposure was sufficient for strain A24 Cruzeiro (A24Cru), both O1 Manisa and Asia1 Shamir transmission required 18h or more. Viral excretion levels from donors (for all three strains) and virus present in room air (for A24Cru and O1 Manisa) were evaluated and associated with clinical signs and observed transmission pattern. Although all directly inoculated donor animals showed acute FMD, A24Cru had the highest levels of viral shedding in saliva and nasal swabs followed by O1 Manisa and Asia1 Shamir. Virus levels in room air were higher and were detected longer for A24Cru than for O1 Manisa. These results provide direct evidence for important strain-specific variation in transmission characteristics and emphasize the need for thorough evaluation of different FMDV viral strains using a well defined contact transmission methodology. This information is critical for vaccine and biotherapeutic efficacy testing, pathogenesis and disease modeling of FMDV transmission.     

RADIOGRAPHIC DIAGNOSIS–PARASPINAL ABSCESS IN A DOG

A two-year-old intact male Brittany Spaniel was admitted for evaluation of progressive spinal pain. Previous treatment had been initiated for suspected lumbosacral intervertebral disk disease, however there was poor response to therapy. On presentation the dog was laterally recumbent and neurological examination revealed hyperesthesia over the lumbar vertebral segments. On survey radiography there was loss of detail in the sublumbar fascial planes and inconclusive lumbar vertebra proliferation. Magnetic resonance (MR) imaging was performed to better evaluate the lumbar spine and surrounding tissues, which revealed extensive paralumbar cellulitis, abscessation and osteomyelitis with extradural compression of the spinal cord. MR imaging allowed delineation of the abscessed area, and distinct visualization of its extension into and involvement of the surrounding tissues including muscle, fat, and retroperitoneal structures. In this case, MR imaging was instrumental in defining the extent of the infection and determining whether medical or surgical management of the diseased tissue was necessary. If available, MR may be the imaging method of choice for evaluation of paraspinal abscesses yielding a better insight to the spinal structures involved and facilitating medical or surgical intervention.     

Raising livestock in resource-poor communities of the North West Province of South Africa--a participatory rural appraisal study

A participatory research model was used in six village communities in the Central Region of the North West Province of South Africa in order to achieve the following broad objectives: to obtain information on the challenges owners face in raising livestock in these areas and to evaluate the livestock owners' level of knowledge of internal parasites in their animals. Information obtained at participatory workshops clearly indicated a need for improvements in water supply, schools, job creation, and health services. Lack of pasture for grazing livestock was also cited as being important. Other most frequently mentioned livestock problems included 'gall sickness' (a vaguely defined condition not necessarily referring to anaplasmosis), parasites (both external and internal), chicken diseases and ingestion of plastic bags discarded in the environment. When livestock owners were questioned during individual interviews, most were able to identify the presence of parasites in either the live or dead animal. However, it seems likely that this is limited to the identification of tapeworms. It was found that most livestock owners use a combination of treatments, ranging from traditional to folklore to commercial. There were some difficulties in using the participatory methods since it was the first time that the facilitators and the communities had been exposed to them. Many communities had difficulty in dealing with the concept of finding solutions within the community, which is such an integral part of participatory methods.     

Crown architecture of stand-grown sugar maple (Acer saccharum Marsh.) in the Adirondack Mountains

Leaf and crown morphology of shade-tolerant sugar maple (Acer saccharum Marsh.) were examined to test the hypotheses (1) that leaf area exhibits significant plasticity both within and between crown classes and individual tree crowns and (2) that leaf area is accurately predicted from estimates of crown volume. A total of 18 trees, ranging from 3.3 to 43.4 cm dbh, were felled and dissected into upper, middle, lower, and below-crown layers, for measurements of leaf, bark, and xylem dimensions. For dominant trees only, bark thickness and xylem radii were higher within the crown than below the crown. Cumulative leaf area index increased with decreasing stratum height at similar rates in all trees, except for two trees that were located in the understory. Area leaf weight declined with decreasing stratum height within the crown of all except four overstory trees. These four trees showed an increase with decreasing stratum height, i.e., leaves were heavier per unit area in the lower crown stratum and below the crown than they were at mid-crown. Within-tree leaf area density was usually higher in the upper crown of overstory trees and in the lower crown of understory trees. Total crown volume was the best predictor of whole-tree leaf area, but it was only slightly better than dbh.     

Age and educational dimensions of recent U.S. migration reversal

The author examines the impact of migration on age and educational structures in nonmetropolitan areas of the United States. In particular, he considers whether migration reversal between 1970 and 1975 had an impact on the traditional draining of the young and better educated from nonmetropolitan areas to the cities     

Effects of anesthesia and surgery on serologic responses to vaccination in kittens

OBJECTIVE: To determine the effects of anesthesia and surgery on serologic responses to vaccination in kittens. DESIGN: Prospective controlled trial. ANIMALS: 32 specific-pathogen-free kittens. PROCEDURES: Kittens were assigned to 1 of 4 treatment groups: neutering at 7, 8, or 9 weeks of age or no neutering. All kittens were inoculated with modified-live virus vaccines against feline panleukopenia virus (FPV), feline herpesvirus (FHV), and feline calicivirus (FCV) at 8, 11, and 14 weeks of age and inactivated rabies virus (RV) at 14 weeks of age. Serum antibody titers against FPV, FHV, and FCV were determined at 8, 9, 11, 14, and 17 weeks of age; RV titers were determined at 14 and 17 weeks of age. RESULTS: Serologic responses of kittens neutered at the time of first vaccination (8 weeks) were not different from those of kittens neutered 1 week before (7 weeks) or 1 week after (9 weeks) first vaccination or from those of kittens that were not neutered. In total, 31%, 0%, 69%, and 9% of kittens failed to develop adequate titers against FPV, FCV, FHV, and RV, respectively, by 17 weeks of age. CONCLUSIONS AND CLINICAL RELEVANCE: Neutering at or near the time of first vaccination with a modified-live virus vaccine did not impair antibody responses in kittens. Many kittens that were last vaccinated at 14 weeks of age had inadequate antibody titers at 17 weeks of age. Kittens may be vaccinated in the perioperative period when necessary, and the primary vaccination series should be extended through at least 16 weeks of age.