Predicting nutrient and sediment loadings to streams from landscape metrics: A multiple watershed study from the United States Mid-Atlantic Region

There has been an increasing interest in evaluating the relative condition or health of water resources at regional and national scales. Of particular interest is an ability to identify those areas where surface and ground waters have the greatest potential for high levels of nutrient and sediment loadings. High levels of nutrient and sediment loadings can have adverse effects on both humans and aquatic ecosystems. We analyzed the ability of landscape metrics generated from readily available, spatial data to predict nutrient and sediment yield to streams in the Mid-Atlantic Region in the United States. We used landscape metric coverages generated from a previous assessment of the entire Mid-Atlantic Region, and a set of stream sample data from the U.S. Geological Survey. Landscape metrics consistently explained high amounts of variation in nitrogen yields to streams (65 to 86% of the total variation). They also explained 73 and 79% of the variability in dissolved phosphorus and suspended sediment. Although there were differences in the nitrogen, phosphorus, and sediment models, the amount of agriculture, riparian forests, and atmospheric nitrate deposition (nitrogen only) consistently explained a high proportion of the variation in these models. Differences in the models also suggest potential differences in landscape-stream relationships between ecoregions or biophysical settings. The results of the study suggest that readily available, spatial data can be used to assess potential nutrient and sediment loadings to streams, but that it will be important to develop and test landscape models in different biophysical settings.     

Stray dog population health in Jodhpur, India in the wake of an animal birth control (ABC) program

Our objectives were to (1) estimate the prevalence of various health indices in the stray dog population in Jodhpur, India and (2) determine if there was an association between an animal birth control (ABC) program and the prevalence of these health indices in this population. A prevalence survey of 323 sexually intact stray dogs >3 months caught from the streets of Jodhpur from September to November, 2005 indicated that low body condition score (70%), skin conditions (69%) and tick infestation (68%) were the most common health problems in this population. An observational study of 888 stray dogs on the streets of Jodhpur from March to April, 2006 revealed that sterilized dogs were more likely to have a higher body condition score (BCS) than sexually intact dogs when controlling for age, based on a multinomial regression model. However, sterilized dogs were more likely to have a skin condition than sexually intact dogs, based on a logistic regression model. Our observations of the surgical/kennel facility indicated that an effective tick control program was needed. Additionally, the current parasite control protocol at the kennel/shelter facility was inadequate to treat mange, a contact-transmitted skin disease. This is the first study to evaluate the associations between an ABC program and stray dog health, apart from rabies.     

COMPUTED TOMOGRAPHIC APPEARANCE OF OSTEOCHONDRITIS DISSECANS-LIKE LESIONS OF THE PROXIMAL ARTICULAR SURFACE OF THE PROXIMAL PHALANX IN A HORSE

A 6-year-old Thoroughbred gelding presented with a left forelimb lameness. The results of lameness examination, radiography, nuclear scintigraphy, and computed tomography are presented. Based on the diagnostic imaging, subchondral fractures and osteochondritis dissecans lesions of the proximal articular surface of the proximal phalanx were diagnosed. A brief discussion of osteochondritis dissecans is presented.     

The Evaluation of Aerial Application Systems1

There is no single measurement technique suitable for the evaluation of all aerial application systems, since the type of measurement required, and the technique used to obtain it, are dependent on the application method. In this paper, techniques used by the authors to assess atomiser performance, droplet dispersion, deposition, and aircraft swath width are described. The applicability of each technique to various application methods is described.     

Estimating the incubation period of raccoon rabies: a time-space clustering approach

We used a time-space clustering approach to estimate the incubation period of raccoon rabies in the wild using data from the 1999-2001 invasion of raccoon rabies into eastern Ontario from northern New York State. The time differences and geographical distances between all possible pairs of rabies cases were computed, classified and assembled into a time-space matrix. The rows of that matrix represented differences in cases in weeks and the columns represent distances between cases in kilometers and the values in the cells of the matrix represent the counts of cases at specific time and distance intervals. There was a significant cluster of pairs 5 weeks apart with apparent harmonics at additional 5-week intervals. These results are explained by assuming the incubation period of raccoon rabies had a mode of 5 weeks. The time clusters appeared consistently at distance intervals of 5 km. We discuss the possibility that the spatial intervals were influenced by the 5 km radius of the point infection control depopulation process used in 1999 and the 10-15 km radial areas used in 2000. With the practical limits of those radii, there was an intensive effort to eliminate raccoons. Our procedure is easy to implement and provides an estimate of the shape of the distribution of incubation periods for raccoon rabies.     

VERTEBRAL HEART SIZE RANGES SPECIFIC FOR WHIPPETS

To assess the influence of breed, breeding lines, and training on heart size, the vertebral heart size (VHS) was evaluated on left-to-right lateral, right-to-left lateral, dorsoventral, and ventrodorsal thoracic radiographs from 44 whippets free from cardiac and pulmonary disease. In lateral views, the VHS was 11.0 +/- 0.5 vertebrae (mean +/- SD) on right-to-left lateral and 11.3 +/- 0.5 vertebrae on left-to-right lateral radiographs, being larger than the 9.7 +/- 0.5 vertebrae proposed by Buchanan (P<0.0001). The VHS on left-to-right lateral views was larger than on right-to-left lateral views (P<0.0001). The VHS was 10.5 +/- 0.6 vertebrae on dorsoventral radiographs and 11.1 +/- 0.6 vertebrae on ventrodorsal radiographs. Both values were larger than the 10.2 +/- 1.5 vertebrae (dorsoventral) (P<0.0082) or 10.2 +/- 0.8 vertebrae (ventrodorsal) (P<0.0001) proposed by Buchanan. In addition, the VHS on ventrodorsal views was larger than on dorsoventral views (P<0.0001). Dogs out of racing pedigree lines had a significantly larger VHS than those out of show pedigree lines, and trained dogs had a significantly larger VHS than nontrained dogs. Because most trained dogs came out of racing pedigree lines, and all nontrained dogs came out of show pedigree lines, however, it is difficult to determine whether the higher VHS for trained dogs is due to genetic influences or training, or both. In conclusion, it is important to take into account the breed and the radiographic view when evaluating heart size in thoracic radiographs of whippets to avoid overinterpretation of cardiac enlargement in these dogs.     

Hand-assisted laparoscopic ovariohysterectomy in the mare

OBJECTIVE: To develop a minimally invasive, hand-assisted laparoscopic ovariohysterectomy (HALS-OHE) technique in the mare and to evaluate safety and any associated complications. STUDY DESIGN: Experimental study. ANIMALS: Eight, 11-24-year-old mares with anatomically normal urogenital tracts. METHODS: The surgical technique was developed in 2 non-survival mares and subsequently evaluated in 6 survival procedures. Food was withheld for 48 hours, then mares were anesthetized and positioned in dorsal recumbency for laparoscopic surgery. A hand access device (Omniport) was placed followed by 4 laparoscopic portals. Transection of the ovarian pedicles and broad ligaments was achieved using a combination of a laparoscopic stapling instrument (Endo GIA II), an ultrasonically activated instrument (Harmonic Scalpel), and endoscopic clips (Endo Clip II ML). The genital tract was exteriorized through the laparotomy, and the uterus transected and sutured in a conventional pattern. Horses were evaluated through postoperative day 14 when a necropsy was performed. RESULTS: Four mares recuperated well after surgery, 1 mare was euthanatized because of bilateral femur fracture during anesthetic recovery, and another developed severe pleuropneumonia. At necropsy all but 1 abdominal incision was healing routinely. One mare had abscessed along the celiotomy incision and developed visceral adhesions. Uncomplicated healing of transected mesovarial, mesometrial, and uterine remnants was observed. CONCLUSIONS: Ovariohysterectomy in horses can be accomplished using HALS technique. CLINICAL RELEVANCE: HALS-OHE technique represents a minimally invasive and technically feasible alternative for conventional OHE. Careful patient selection and preparation may reduce the complications observed. The HALS technique may be useful in other laparoscopic surgical procedures.