Space,Time, and Local Employment Growth: An Application of Spatial Regression Analysis

ABSTRACT Local and regional employment growth is generally studied either by searching for local qualitative explanatory factors such as governance, synergy between firms, and milieu effects, or by searching for general growth factors using statistical techniques. The body of work that relies on this approach has tended, in keeping with economics’ nomothetic tradition, to assume that local and regional growth factors are constant over space. The focus of this paper is on exploring the spatial stationarity of employment growth factors in Canada, but it also seeks to clarify some of the broad principles behind spatial regression techniques in order to provide a point of entry and a conceptual framework for empirical researchers. To do so, we apply a recently developed technique, Geographically Weighted Regression (GWR), and we explore the method's advantages and limits for answering our research question. We find evidence that growth factors differ across Canada, but we also conclude that the GWR technique, given the number and shape of regions available for our analysis and given certain limitations that are currently inherent to the method, can only provide tentative and exploratory results.     

Dirofilaria immitis in cats from inner Sydney

Two hundred feral cats from the inner suburbs of Sydney were examined post mortem for adult Dirofilaria immitis and circulating microfilariae, and 101 of these cats were tested for heartworm antigens by an ELISA. Only 2 cats (1%) had adult heartworms, the blood sample from another cat contained a single microfilaria. The blood of a further three cats contained small amounts of D immitis antigen. Although D immitis occurs in cats in Sydney, the prevalence is not high enough to warrant prophylactic treatment.     

Diversity of Salmonella serovars in feedyard and nonfeedyard playas of the Southern High Plains in the summer and winter

OBJECTIVE: To compare Salmonella isolates cultured from feedyard and nonfeedyard (control) playas (ie, temporary shallow lakes) of the Southern High Plains. SAMPLE POPULATION: Water and muck (sediment) samples were obtained from 7 feedyard playas and 3 nonfeedyard playas in the winter and summer. PROCEDURE: Each water and muck sample was enriched with sulfur-brilliant-green broth and incubated in a shaker at 37 degrees C for 24 hours. A sample (100 mL) of the incubated bacterial-enriched broth was then mixed with 100 mL of fresh sulfur-brilliant-green enrichment broth and incubated in a shaker at 37 degrees C for 24 hours. After the second incubation, a swab sample was streaked on differential media. Suspect Salmonella isolates were further identified by use of biochemical tests, and Salmonella isolates were confirmed and serovar determinations made. RESULTS: Salmonella isolates were not recovered from the 3 control playas. Seven Salmonella enterica serovars were isolated from 5 of 7 feedyard playas in the summer, and 13 S. enterica serovars were isolated from 7 of 7 feedyard playas in the winter. In the summer, 296 isolates were cultured, and 47 were Salmonella organisms. In the winter, 288 isolates were cultured, and 171 were Salmonella organisms. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that feedyard playas are frequently contaminated with many Salmonella serovars. These pathogens should be considered whenever feedyard managers contemplate the use of water from these playas. Water from feedyard playas should not be used to cool cattle in the summer or for dust abatement.     

Expression of Perilipin 2 (PLIN2) in Porcine Oocytes During Maturation

Perilipins have been reported to limit the interaction of lipases with neutral lipids within the droplets, thereby regulating neutral lipid accumulation and utilization. This study aimed to identify the location and expression of PLIN1 and PLIN2 in porcine oocytes during maturation. Quantitative real‐time polymerase chain reaction (qRT‐PCR), immunostaining and Western blot methods were used to characterize the expression and distribution patterns of PLIN1 and PLIN2 in porcine oocytes. The results showed that PLIN1 was not detectable in porcine oocytes. PLIN2 and BODIPY 493/503‐detected neutral lipid droplets appeared identical distribution patterns and extensive colocalization in both GV and MII porcine oocytes. PLIN2 protein expression was higher in GV oocytes than that in MII oocytes (p < 0.05), although PLIN2 mRNA expression was similar in both groups. These findings suggested that PLIN2 was a major lipid droplet‐associated protein in porcine oocytes.     

Congenital hypothyroidism in Scottish Deerhound puppies

Two Scottish Deerhound puppies had clinical and pathological features consistent with the diagnosis of congenital non-goitrous hypothyroidism. They were from separate litters, but were the progeny of the same sire and dam. The puppies were smaller, had shorter limbs and shorter, broader heads than their littermates. They also had histories of weakness, difficulty in walking and somnolence. A characteristic radiographic feature was the absence of epiphyseal growth centres. Both had depressed serum thyroxine (T4) levels and one did not respond to exogenous thyroid stimulating hormone. On necropsy, the thyroid glands were small, the follicles varied in size and contained little or no colloid. The adenohypophysis contained many cells with markedly vacuolated cytoplasm. It is suggested that the clinicopathological pattern is the result of a primary thyroid abnormality. Possible mechanisms include either primary thyroid hypoplasia or an unresponsiveness to thyroid stimulating hormone.     

Effect of water hardness on peracetic acid toxicity to zebrafish, Danio rerio, embryos

The use of peracetic acid (PAA) in aquaculture has been suggested as an alternative therapeutic agent. Few data are available concerning fish toxicity by PAA or factors that modify this toxicity. The aim of this study was to investigate the influence of water hardness on the acute toxicity of PAA products to embryos of zebrafish (Danio rerio). Embryos were exposed to PAA ranging from 0 to 9 mg/L in low-hardness (1.4 °dH or 25 mg/L hardness as CaCO₃), medium-hardness (14 °dH or 250 mg/L hardness as CaCO₃) and high-hardness (140 °dH or 2,500 mg/L hardness as CaCO₃) waters. The lowest LC50 value was 2.24 mg/L PAA in the low-hardness water, and the highest LC50 value was 7.14 mg/L PAA in the high-hardness water. Toxicity of PAA to embryos was found to be negatively correlated with water hardness. The pH decreased with increasing concentrations of PAA, and the test waters were observed to become more acidic in low hardness. In conclusion, aquaculturists using PAA should pay attention to water hardness to avoid acidosis.     

Inhibiting fungus on largemouth bass eggs with copper sulfate and its toxicity to fry and juveniles

This study determined the effectiveness of copper sulfate (CuSO₄) to inhibit fungal growth (caused by Saprolegnia spp.) on largemouth bass (LMB) eggs spawned on/in fiber mats in very high-alkalinity/-hardness waters; experiments also determined the toxicity of CuSO₄ to LMB fry and juveniles. An untreated control and three CuSO₄ concentrations (10, 20, and 40 mg/L) were tested under a flow-through scenario in the effectiveness experiment. Eggs were treated daily until hatching began. Fungal load at the time of hatch had a total area > 3.0 cm² in the untreated controls, total area 1.0 to <2.0 cm² in the 10 and 20 mg/L CuSO₄ treatments, and total area > 1.0 cm² in the 40 mg/L CuSO₄ treatments. Fungus samples were identified as Saprolegnia australis. The 24-hr median lethal concentration (LC50) values on the LMB yolk-sac and swim-up fry were 32.0 and 4.6 mg/L CuSO₄, respectively; the No Observed Effect Concentrations (NOEC) were 16.0 and 0.125 mg/L CuSO₄, respectively. Juvenile LMB were extremely tolerant to CuSO₄, and their 24-hr LC50 value was 185.5 mg/L; the NOEC was 64 mg/L. This study indicates that CuSO₄ can be an important resource for hatcheries to control egg fungus, especially in high-alkalinity/-hardness waters.     

Johne's disease in alpacas (Lama pacos) in Australia

SUMMARY: Johne's disease was diagnosed in 10 alpacas ( Lama pacos ) in Australia between February 1993 and May 1994. Eight of the animals were between 12 and 24 months of age, one was a 6-year-old female, and one was a 4-year-old male. Five, including the 6-year-old and the 4-year-old alpacas, showed weight loss and diarrhoea before death or slaughter. The other cases showed no clinical signs of Johne's disease but 4 gave a positive result on faecal culture and one gave a positive result on testing with the caprine ACID assay and had acid-fast organisms in its faeces. At necropsy, all cases had grossly enlarged mesenteric lymph nodes. Johne's disease was diagnosed after histological examination of the lymph nodes with conventional culture and polymerase chain reaction testing of tissue samples. This report outlines the clinical, epidemiological, and pathological findings in these cases.