Effects of pectoral fin ray removal on Siberian sturgeon <Emphasis Type="Italic">Acipenser baerii</Emphasis> swimming performance     

Phong L. Nguyen  Zachary J. Jackson  Douglas L. Peterson 《Fisheries Science》2017,83(5):785-793

Fin ray biopsies are commonly used to age sturgeon, but the effects of fin ray biopsy on Siberian sturgeon Acipenser baerii swimming performance are unknown. Therefore, the effects of two fin ray biopsy methods on swimming performance of hatchery-reared, juvenile Siberian sturgeon were evaluated in this study. Treatment fish were subjected to one of two biopsy methods: removal of a 2- to 4-cm section from a marginal pectoral fin ray, or full removal of a marginal pectoral fin ray. Control fish were only subjected to a sham operation. A modified 2,936-l Brett-type swim tunnel was used to evaluate 10-min critical station-holding speeds (C _SHS) and behavioral swimming characteristics of sturgeon immediately after fin ray biopsies were carried out. Fish sizes (range 65- to 84-cm fork length) were comparable among treatments. Mean 10-min C _SHS (mean ± SE) were 113 ± 3.4, 109 ± 2.5, and 111 ± 2.8 cm s^?1 for the segment removal treatment, full removal treatment, and control treatment, respectively. ANOVA indicated that the two methods had no significant effect on the 10-min C _SHS of Siberian sturgeon compared to the control treatment. Results indicate that fin ray removal has no effect on Siberian sturgeon swimming performance.  相似文献   

What matters for lagging regions? The role of self-employment and industrial diversity in distressed areas     

Zachary T. Keeler  Heather M. Stephens 《Growth and change》2023,54(4):962-1001

Previous research suggests that having more self-employed or entrepreneurs can contribute to higher levels of economic growth in distressed areas. Additionally, self-employment in certain industries may be more beneficial to growth. Other research has linked industrial diversity to entrepreneurship and regional growth, especially in urban areas. However, the relationship between industrial diversity, self-employment, and growth in lagging or distressed regions is less clear. To examine these linkages in distressed areas, we first identify a group of distressed counties based on historic data. Then, using detailed industry-level self-employment data, we appraise whether having more self-employed from certain industries is associated with regional growth. We also analyze the relationship between industrial diversity and overall growth and the propensity to be self-employed. The results suggest that having more self-employment overall and in some key industries is associated with more employment growth in distressed counties. We also find that the relationship between economic diversity and self-employment varies by industry and region.  相似文献   

An Eperythrozoon-like parasite in llamas   总被引：9，自引：0，他引：9  

B G McLaughlin  C N Evans  P S McLaughlin  L W Johnson  A R Smith  J F Zachary 《Journal of the American Veterinary Medical Association》1990,197(9):1170-1175

An Eperythrozoon-like RBC parasite was found in a herd of llamas in western Kentucky. The light microscopic and electron microscopic features of the organism were similar to those of E suis. Results of an indirect hemagglutination test for E suis were positive with sera from some parasitemic and nonparasitemic llamas. Parasitemic llamas were usually less than 1 year old and had more severe clinical signs of disease than did older llamas. Poor weight gain and growth, anorexia, and prolonged recumbency were the principal signs of disease. Anemia was usually mild and not accompanied by icterus. Hypoglycemia was associated with parasitemia. Some response to oral or parenteral treatment with tetracycline was noticed, but recrudescence of the infection in some treated llamas was observed. Llamas in nearly every region of the United States have had titers in approximately 12% of samples tested, suggesting that infection with the organism may be widespread. Parasitemic llamas have been recognized in at least 8 states.  相似文献   

Neurologic manifestations of cerebrovascular atherosclerosis associated with primary hypothyroidism in a dog   总被引：2，自引：0，他引：2  

J S Patterson  M S Rusley  J F Zachary 《Journal of the American Veterinary Medical Association》1985,186(5):499-503

A 6-year-old, obese, spayed female Doberman pinscher dog was presented for clinical examination with a 1-day history of repeated seizures and a long-term history of periodic bouts of ataxia, circling, and head tilt. The seizures were controlled with phenobarbital, but the dog died 2 days after presentation. Necropsy revealed severe, diffuse, follicular atrophy of the thyroid gland (primary hypothyroidism), severe generalized atherosclerosis, severe pseudolaminar cortical necrosis and acute vasculitis in the cerebrum, and congestive heart failure. The neurologic signs were explained by the pseudolaminar necrosis and associated cerebrovascular atherosclerosis. The cerebrocortical necrosis was believed to be caused by tissue hypoxia secondary to progressive vascular occlusion. Cerebrovascular atherosclerosis, secondary to primary hypothyroidism, was considered the most important cause of the hypoxia.  相似文献   

Ontogenetic variability of maternal effects in an iteroparous fish          下载免费PDF全文

Sara R. Andree  Zachary S. Feiner  Jacob W. Bledsoe  Aaron M. Cragun  Tomas O. Höök 《Ecology of Freshwater Fish》2015,24(3):384-396

Maternal effects have been observed to interact with genotypic and environmental influences to structure offspring phenotypes across a wide variety of taxa. In fishes, maternal effects may be especially important due to their potential influence on development and survival during early ontogeny – a period with high potential for population regulation. While previous studies have confirmed that maternal effects on offspring phenotype are common in fishes, the consistency with which they positively affect offspring fitness throughout early ontogeny remains largely unknown. We examined maternal effects on offspring fitness by quantifying relationships between maternal (length, mass and age), egg (diameter, mass and density) and larval traits (length, yolk‐sac volume and survival) in yellow perch (Perca flavescens). Consistent with several past studies, positive relationships among maternal and egg traits were evident. While egg mass was positively related to larval size at hatching, direct relationships between maternal and larval metrics were not apparent. Larval survival appeared to have two critical periods; in contrast with expectations, survival in the first 5 days posthatch was strongly negatively related to female size and age, while survival over the following 9 days was unrelated to maternal traits. Throughout the study, survival was positively related to yolk‐sac volume. Our unexpected observation of a negative relationship between maternal size and age and initial larval survival indicates that maternal effects may not be consistent throughout larval ontogeny. In fact, maternal effects appear to be dynamic influences on offspring fitness, and may have complex effects on individual‐ and population‐level reproductive success.  相似文献   

Prospective,Double-Blind,Randomized, Placebo-Controlled Comparison of Acetazolamide Versus Ibuprofen for Prophylaxis Against High Altitude Headache: The Headache Evaluation at Altitude Trial (HEAT)     

Jeffrey H. Gertsch  Grant S. Lipman  Peter S. Holck  Andrew Merritt  Allison Mulcahy  Robert S. Fisher  Buddha Basnyat  Eric Allison  Keeli Hanzelka  Alberto Hazan  Zachary Meyers  Justin Odegaard  Benjamin Pook  Mark Thompson  Brant Slomovic  Henrik Wahlberg  Vanessa Wilshaw  Eric A. Weiss  Ken Zafren 《The Forestry Chronicle》2010,21(3):236-243

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Individual and spatial variation are as important as species‐level variation to the trophic complexity of a lentic food web     

Zachary S. Feiner  Carolyn J. Foley  Robert K. Swihart  Harvey Bootsma  Sergiusz Czesny  John Janssen  Jacques Rinchard  Tomas O. Hk 《Ecology of Freshwater Fish》2019,28(4):516-532

Ecological complexity may improve ecosystem function, stability and adaptability to natural and anthropogenic disturbances. Intraspecific trophic variation can represent a significant component of total community variation and can influence food web structure and function. Thus, understanding how trophic niches are partitioned between intraspecific and interspecific processes could improve our understanding of food web dynamics. We examined gut contents, fatty acids and stable isotope ratios in round goby (Neogobius melanostomus) and yellow perch (Perca flavescens) across six sites in Lake Michigan, USA, to determine patterns in intra‐ and interspecific trophic composition (i.e., mean gut or fatty acid composition) and diversity (i.e., the diversity of gut items or fatty acids). We also examined relationships between fatty acid diversity and gut content characteristics to understand potential mechanisms shaping individual trophic phenotypes. There was significant variation in both trophic composition and diversity among sites, and individual and spatial variation was as important to total trophic variation as species identity. Round goby that consumed dreissenid mussels had more diverse fatty acid profiles than those that consumed other benthic invertebrates, whereas yellow perch fatty acid diversity was not related to gut content composition. Our results confirm that intraspecific variation in resource use can be as important to trophic dynamics as interspecific variation, and that spatial variation in lower level food web processes or habitat may strongly structure local food web dynamics. Individual‐level examination of trophic diversity, in concert with trophic composition, could provide additional information about the resilience, function and adaptability of local food webs.  相似文献   

Biomonitoring the Cooked Meat Carcinogen 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in Canine Fur     

D Gu  ZL Neuman  JF Modiano  RJ Turesky 《Journal of agricultural and food chemistry》2012,60(36):9371-9375

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic aromatic amine (HAA) that is formed during the cooking of meat, poultry, and fish. PhIP is a rodent carcinogen and is thought to contribute to several diet-related cancers in humans. PhIP is present in the hair of human omnivores but not in the hair of vegetarians. We have now identified PhIP in the fur of 14 out of 16 healthy dogs consuming different brands of commercial pet food. The levels of PhIP in canine fur varied by over 85-fold and were comparable to the levels of PhIP present in human hair. However, high density fur containing PhIP covers a very high proportion of the body surface area of dogs, whereas high density terminal hair primarily covers the scalp and pubis body surface area of humans. These findings signify that the exposure and bioavailability of PhIP are high in canines. A potential role for PhIP in the etiology of canine cancer should be considered.  相似文献   

Corrigendum to “Optimization of hydrolytic and oxidative enzyme methods for ecosystem studies” [Soil Biol. Biochem. 43 (2011) 1387–1397]     

Donovan P. German  Michael N. Weintraub  A. Stuart Grandy  Christian L. Lauber  Zachary L. Rinkes  Steven D. Allison 《Soil biology & biochemistry》2012,44(1):151

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A pilot study evaluating changes in pancreatic lipase immunoreactivity concentrations in canines treated with L-asparaginase (ASNase), vincristine, or both for lymphoma          下载免费PDF全文

Zachary Wright  Joerg Steiner  Jan Suchodolski  Kenita Rogers  Claudia Barton    Marjorie Brown 《Canadian journal of veterinary research》2009,73(2):103-110

L-asparaginase (ASNase) is a common chemotherapy agent for the treatment of lymphoid malignancies. L-asparaginase has been reported to cause clinical pancreatitis in both humans and canines. Canine pancreatic lipase immunoreactivity (cPLI) is now a common diagnostic tool for evaluating pancreatitis in dogs. A total of 52 dogs were enrolled into this study. Canine pancreatic lipase immunoreactivity (cPLI) concentrations were evaluated before and after administration of ASNase, vincristine, or both. All dogs enrolled in the study were evaluated for signs compatible with clinical pancreatitis. No dogs receiving ASNase alone showed evidence of clinical pancreatitis after administration. Also, there was no statistically significant change in cPLI concentrations before or after treatment. Fourteen percent of dogs that received both vincristine and ASNase concurrently had elevated concentrations of cPLI after treatment. Of the 11 dogs with clinical signs compatible with pancreatitis after any chemotherapy treatment, no dog had a cPLI concentration > 400 μg/dL. In conclusion, ASNase did not cause clinical pancreatitis in this cohort of dogs but larger sample sizes are required to further validate this data.  相似文献