Growth and nutritional responses of bareroot Jeffrey pine on a Sierra Nevada surface mine to minisite applications of fertilizer and lime     

Walker  R.F. 《New Forests》2002,24(3):225-238

The effects of two controlled release fertilizers, Forestcote 22-4-6 + Minors and Dry Site 21-6-2 + Minors, and also dolomitic lime, on growth and nutrition of bareroot Jeffrey pine (Pinus jeffreyi Grev. & Balf.) were investigated. Forestcote, which consists of loose prills, and Dry Site, consisting of prepackaged prills, were administered with two rates, while a single liming rate was used. An acidic Sierra Nevada surface mine provided the study site, and all amendments were applied at outplanting to the backfill of augered planting holes. Without impacting survival, both fertilizer formulations enhanced seedling growth, particularly at a 16 g rather than an 8 g application rate, although Forestcote was marginally more effective in this regard. In contrast, liming at a 27 g rate induced severe mortality and offset much of the growth gains resulting from fertilization. Improvements in N and P nutrition, as revealed by foliar analysis, probably accounted for much of the growth stimulation exhibited by fertilized seedlings, but reductions in the uptake of potentially phytotoxic trace elements such as Mn and Al and increases in base cation/metallic element ratios likely also contributed. The high application rate was generally preeminent in eliciting these nutritional responses. Liming induced little alteration of seedling nutrition. Impaired water relations may have caused the unfavorable responses to this treatment.  相似文献   

SCINTIGRAPHIC TRACKING OF MESENCHYMAL STEM CELLS AFTER PORTAL,SYSTEMIC INTRAVENOUS AND SPLENIC ADMINISTRATION IN HEALTHY BEAGLE DOGS          下载免费PDF全文

Mathieu Spriet  Geraldine B. Hunt  Naomi J. Walker  Dori L. Borjesson 《Veterinary radiology & ultrasound》2015,56(3):327-334

Mesenchymal stem cells have been proposed to treat liver disease in the dog. The objective of this study was to compare portal, systemic intravenous and splenic injections for administration of mesenchymal stem cells to target the liver in healthy beagle dogs. Four healthy beagle dogs were included in the study. Each dog received mesenchymal stem cells via all three delivery methods in randomized order, 1 week apart. Ten million fat‐derived allogeneic mesenchymal stem cells labeled with Technetium‐99m (99mTc)‐hexamethyl‐propylene amine oxime(HMPAO) were used for each injection. Right lateral, left lateral, ventral, and dorsal scintigraphic images were obtained with a gamma camera equipped with a low‐energy all‐purpose collimator immediately after injection and 1, 6, and 24 h later. Mesenchymal stem cells distribution was assessed subjectively using all four views. Pulmonary, hepatic, and splenic uptake was quantified from the right lateral view, at each time point. Portal injection resulted in diffuse homogeneous high uptake through the liver, whereas the systemic intravenous injection led to mesenchymal stem cell trapping in the lungs. After splenic injection, mild splenic retention and high homogeneous diffuse hepatic uptake were observed. Systemic injection of mesenchymal stem cells may not be a desirable technique for liver therapy due to pulmonary trapping. Splenic injection represents a good alternative to portal injection. Scintigraphic tracking with 99mTc‐HMPAO is a valuable technique for assessing mesenchymal stem cells distribution and quantification shortly after administration. Data obtained at 24 h should be interpreted cautiously due to suboptimal labeling persistence.  相似文献   

Changes in the phytochemical composition and profile of raw, boiled, and roasted peanuts     

Chukwumah Y  Walker L  Vogler B  Verghese M 《Journal of agricultural and food chemistry》2007,55(22):9266-9273

Peanuts are consumed mostly as processed products. Although the effect of processing on isoflavone composition of legumes has been extensively studied, there has been no such study on peanuts. The objective of this study was to evaluate the effect of processing (boiling, oil- and dry-roasting) on the phytochemical composition of peanuts. Boiling had a significant effect on the phytochemical composition of peanuts compared to oil- and dry-roasting. Boiled peanuts had the highest total flavonoid and polyphenol content. The biochanin A and genistein content of boiled peanut extracts were two- and fourfold higher, respectively. trans-Resveratrol was detected only in the boiled peanuts, with the commercial product having a significantly (p < or = 0.05) higher concentration. Ultraviolet and mass spectrometry chromatograms for the boiled peanut extracts show the presence of four additional peaks that were not observed in the raw peanut extracts.  相似文献   

Childhood cancer in Texas counties with moderate to intense agricultural activity     

Walker KM  Carozza S  Cooper S  Elgethun K 《Journal of agricultural safety and health》2007,13(1):9-24

With few established risk factors, cancer remains the second leading cause of death for children in the U.S. Agricultural pesticide use is one of many suspected factors that may contribute to the etiology of childhood cancer. This study tests the hypothesis that birth in Texas counties with moderate to intense agricultural activity increases childhood cancer risk. This case-control study analyzed 6974 cases and controls ages 0 to 14, identified through the Texas Cancer Registry and Texas birth records, respectively. Exposure data were obtained from the Census of Agriculture. Percent cropland in the county of birth and total county-specific pesticide exposure incorporating the EPA's carcinogenicity classification served as surrogates for pesticide exposure. Cancer sites examined include: all cancers, leukemia, lymphoma, CNS tumors, and several specific subsites. Elevated, although not statistically significant, ORs for the association between birth in counties with > or =50% cropland were produced for all CNS tumors (OR = 1.3, 95% CI = 0.9-1.8), astrocytoma (OR = 1.4, 95% CI = 0.8-2.2), and PNET (OR = 1.3, 95% CI = 0.7-2.5). A similar pattern was not observed using the index of total county-specific pesticide exposure. Although imprecise, these exposure assessment methods represent novel applications of agricultural census data. Although a pattern of increased risk was observed between percent cropland and CNS tumors, this study's results do not support an association between birth in Texas counties with moderate to intense agricultural activity and childhood cancer. Due to study limitations, such an association should not be ruled out. Future research should incorporate individual-level data from various sources to increase precision and decrease misclassification in the exposure assessment.  相似文献   

Effects of oral powder electrolyte administration on packed cell volume,plasma chemistry parameters,and incidence of colic in horses participating in a 6-day 162-km trail ride     

Wade T. Walker  Robert J. Callan  Ashley E. Hill  Kelly B. Tisher 《The Canadian veterinary journal. La revue veterinaire canadienne》2014,55(8):765-771

This study evaluated the effects of administering oral powder electrolytes on packed cell volume (PCV), plasma chemistry parameters, and incidence of colic in horses participating on a 6-day 162-km trail ride in which water was not offered ad libitum. Twenty-three horses received grain with powder electrolytes daily while 19 control horses received grain only. Horses were ridden approximately 32 km a day at a walk or trot. Packed cell volume and plasma chemistry parameters were analyzed daily. Episodes of colic were diagnosed and treated by a veterinarian unaware of treatment group allocation. Blood parameters and incidence of colic were compared between treatment groups. Electrolyte administration did not alter PCV or plasma chemistry parameters compared to controls. The incidence of colic was significantly higher in treated horses (P = 0.05). Oral powder electrolytes did not enhance hydration status or electrolyte homeostasis and may be associated with colic in horses participating on long distance trail rides similar to this model.  相似文献   

First isolation of sleeping disease virus from rainbow trout, Oncorhynchus mykiss (Walbaum), in the United Kingdom     

Graham DA  Rowley HM  Walker IW  Weston JH  Branson EJ  Todd D 《Journal of fish diseases》2003,26(11-12):691-694

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Impacts of Bolbophorus damnificus (Digenea: Bolbophoridae) on Production Characteristics of Channel Catfish,Ictalurus punctatus,Raised in Experimental Ponds     

David J. Wise  Menghe H. Li  Matt J. Griffin  Edwin H. Robinson  Lester H. Khoo  Terrence E. Greenway  Todd S. Byars  Josh R. Walker  Charles C. Mischke 《Journal of the World Aquaculture Society》2013,44(4):557-564

Bolbophorus damnificus was recognized as a threat to channel catfish, Ictalurus punctatus, production in Louisiana and Mississippi in 1997 and 1999, respectively. Severe to moderate outbreaks (≥34% prevalence) are correlated to heavy losses, but impact of mild outbreaks with low prevalence (<33%) was unknown. Laboratory and field studies were conducted to evaluate sublethal acute (early stage) and chronic (late stage) trematode infection impacts on catfish production. Fish raised in ponds seeded with ram's horn snails from ponds harboring active B. damnificus outbreaks resulted in infection prevalence ranging from 1.6 to 20.4%. Compared to fish raised in ponds not seeded with infected snails (0% prevalence), fish biomass, number harvested, and total feed fed were significantly lower. These data agree with previous studies where mild infections reduced feed consumption, fish production, and economic returns. Infected fish were collected from ponds and used in a laboratory growth study. Once removed from the infection source, weight gain, growth rate, feed consumption, and feed efficiency were equal to or greater than trematode‐free fish. This suggests that although early B. damnificus infection (premetacercarial development) can severely impact production, infection has little impact on performance once metacercarial cysts are fully developed, and the infection source is removed.  相似文献   

Immunization against 5α-androstenone in boarsL'immunisation contre la 5-androsténone chez le verratImmunisierung gegen 5α-Androstenon in Ebern     

E.D Williamson  R.L.S Patterson  E.R Buxton  K.G Mitchell  I.G Partridge  N Walker 《Livestock Production Science》1985,12(3):251-264

The effects of specific immunization against 5α-androstenone have been examined in large, genetically homologous groups of boars reared either to bacon weight (90–95 kg live weight) or to heavy manufacturing weight (115–120 kg live weight). At the lighter weight, immunization significantly (P < 0.05) reduced the concentration of androstenone in the adipose tissue from a mean value of 1.77 (S.E. 0.2) μg g^?1 fat in untreated boars (n=39) to 1.10 (S.E. 0.18) μg g^?1 for animals (n=19) treated with 5α-androstene-3-BSA. In contrast, boars (n=20) treated with 5α-androstenone-11-BSA as immunogen accumulated androstenone to a level of 1.99 μg g^?1 fat (S.E. 0.38). At the heavier weight, immunization reduced the accumulation of androstenone in adipose tissue from a mean value of 1.81 μg g^?1 fat (S.E. 0.22) in untreated boars (n=76) to 1.17 μg g^?1 (S.E. 0.19) for animals (n=22) treated with androstene-3-BSA as immunogen. In contrast, boars (n=21) treated with androstenone-11-BSA as immunogen accumulated androstenone to a mean level of 1.74 μg g^?1 fat (S.E. 0.46). No detrimental side-effects were observed in the immunized animals and the advantages of male-type performance and carcass composition were fully preserved.  相似文献   

Effect of level of intake and supplemental barley on marker estimates of fecal output using an intraruminal continuous-release chromic oxide bolus     

P G Hatfield  J W Walker  H A Glimp  D C Adams 《Journal of animal science》1991,69(4):1788-1794

Sixty wethers (average BW = 45 kg) fitted with fecal collection bags were used in four experiments to evaluate the ability of a intraruminal continuous-release chromic oxide bolus to predict fecal DM output. In Exp. 1, 18 wethers housed in metabolism crates were fed barley at either 0, 100, or 200g/d and allowed ad libitum consumption of alfalfa pellets. In Exp. 2, 18 wethers were housed in metabolism crates and fed alfalfa pellets at either 70, 85, or 125% of pre-study ad libitum consumption. In Exp. 3, 12 wethers grazed a sagebrush-bunchgrass range and were individually fed barley at 0 or 200 g/d. In Exp. 4, 12 wethers grazed either an ungrazed (383 kg/ha herbaceous biomass) or a heavily grazed (175 kg/ha herbaceous biomass) sagebrush-bunchgrass range. Experiments 1 and 2 were balanced 3 x 3 Latin squares, and Exp. 3 and 4 were crossover designs. Chromium content was determined in rectal grab samples. Treatment effects were compared using marker-estimated fecal output divided by total fecal collection, multiplied by 100, as the dependent variable. Accuracy of the estimate was verified by comparing marker-estimated fecal output with total fecal collection using a paired t-test. In Exp. 1 and 2, treatments were different (P less than .05). No differences (P greater than .50) were detected in Exp. 3 and 4. In Exp. 1, 2, and 3 accuracy was different (P less than .02) among wethers within study and treatment. Only in Study 4 were minor or no differences (P greater than .09) in accuracy found.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Strangles in horse studs: incidence, risk factors and effect of vaccination     

JK FAIRLEY 《Australian veterinary journal》1991,68(8):282-283

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