Physical and hydraulic properties of baked ceramic aggregates used for plant growth medium.     

Susan L Steinberg  Gerard J Kluitenberg  Scott B Jones  Nihad E Daidzic  Lakshmi N Reddi  Ming Xiao  Markus Tuller  Rebecca M Newman  Dani Or  J Iwan D Alexander 《Journal of the American Society for Horticultural Science》2005,130(5):767-774

Baked ceramic aggregates (fritted clay, arcillite) have been used for plant research both on the ground and in microgravity. Optimal control of water and air within the root zone in any gravity environment depends on physical and hydraulic properties of the aggregate, which were evaluated for 0.25-1-mm and 1-2-mm particle size distributions. The maximum bulk densities obtained by any packing technique were 0.68 and 0.64 g cm-3 for 0.25-1-mm and 1-2-mm particles, respectively. Wettable porosity obtained by infiltration with water was approximately 65%, substantially lower than total porosity of approximately 74%. Aggregate of both particle sizes exhibited a bimodal pore size distribution consisting of inter-aggregate macropores and intra-aggregate micropores, with the transition from macro- to microporosity beginning at volumetric water content of approximately 36% to 39%. For inter-aggregate water contents that support optimal plant growth there is 45% change in water content that occurs over a relatively small matric suction range of 0-20 cm H2O for 0.25-1-mm and 0 to -10 cm H2O for 1-2-mm aggregate. Hysteresis is substantial between draining and wetting aggregate, which results in as much as a approximately 10% to 20% difference in volumetric water content for a given matric potential. Hydraulic conductivity was approximately an order of magnitude higher for 1-2-mm than for 0.25-1-mm aggregate until significant drainage of the inter-aggregate pore space occurred. The large change in water content for a relatively small change in matric potential suggests that significant differences in water retention may be observed in microgravity as compared to earth.  相似文献   

Comparative diagnostic test characteristics of oscillometric and Doppler ultrasonographic methods in the detection of systolic hypertension in dogs     

Stepien RL  Rapoport GS  Henik RA  Wenholz L  Thomas CB 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(1):65-72

Comparison of test characteristics allows a clinician to choose the optimal diagnostic test method for an individual patient. This study assessed the comparative test characteristics of noninvasive (NI) blood pressure measurement methods (oscillometric and Doppler) and used this information to develop optimal cutoff values for diagnosis of systolic hypertension in dogs by these NI methods. Simultaneous NI (oscillometric or Doppler methods) and invasive (arterial puncture [AP]) systolic blood pressure (SBP) measurements were obtained prospectively from normal dogs and dogs suspected of having systemic hypertension based on clinical signs. Oscillometric SBP readings were obtained from the distal hind limb (Osc-L, n = 54) or the proximal tail (T. n = 27). Doppler BP measurements were obtained using a forelimb cuff (n = 57). AP-SBP was categorized as hypertensive if > or = 160 mmHg, and sensitivity (Se). specificity (Sp), and likelihood ratios (LR) were calculated for diagnostic cutoff values ranging from 130 to 220 mmHg. Receiver operator characteristic (ROC) curves were analyzed to determine optimal cutoff values for diagnosis of AP-SBP > or = 160 mmHg. Optimal NI SBP cutoff values considered to reflect AP values > or = 160 mmHg were: Osc-L = 160 mmHg (Se: 65%, Sp: 85%. LR = 4.33: 1), Osc-T = 150 mmHg (Se: 84%, Sp: 75%, LR = 3.36: 1), and Doppler = 160 mmHg (Se: 71%,  相似文献   

Intralesional administration of formalin for treatment of epidermal inclusion cysts in five horses     

Frankeny RL 《Journal of the American Veterinary Medical Association》2003,223(2):221-2, 197

Five horses with unilateral epidermal inclusion cysts located in the nasal diverticula were sedated and treated with intralesional injection of neutral-buffered 10% formalin (volume range, 2 to 4.5 mL). After aspiration of the cyst, formalin was injected intralesionally until leakage of fluid around the needle was observed. After several weeks, desiccation of the cyst was evident; it was excised 2 weeks after treatment in 3 horses, digitally removed by the owner of 1 horse, and never removed in 1 horse, because the owner declined further treatment after resolution of the original swelling of the nasal diverticulum. Swelling of the cyst after treatment was observed in all horses; nasal discharge (2 horses) and a mild episode of epistaxis (1 horse) were the only other complications of the treatment. Intralesional administration of formalin appears to be a simple and effective treatment for epidermal inclusion cysts in the nasal diverticula of horses.  相似文献   

Associations between yearling body measurements and career racing performance in Thoroughbred racehorses     

Adriana M. Smith BSc  W. Burton Staniar PhD  Rebecca K. Splan PhD 《Journal of Equine Veterinary Science》2006,26(5):212-214

Yearling morphometric measurements and variables related to career racing performance were collected on 260 Thoroughbreds to determine correlations between and among these traits. Morphometric measurements were adjusted to 365 days based on interpolation from adjacent age points and included wither and hip height, body length, distal limb length, cannon circumference, heartgirth circumference, and chest width. Measures of career racing ability included total earnings, win percentage, and Standard Starts Index (SSI). Wither height and hip height were favorably correlated with lifetime earnings, SSI, and win percentage. Body length and heartgirth were positively correlated with SSI and win percentage. Leg traits were not correlated with any performance parameters. Horses that had placed in or won a stakes race tended to be taller at the wither and hip as yearlings. Horses categorized as preferring turf tended to be taller at the wither and hip at 365 days than those that preferred to run on dirt. No significant difference in yearling morphometric measurements between sprinters and routers was detected. In addition to phenotype and pedigree information, morphometric measurements taken in the yearling year may allow for more accurate estimation of future performance in the Thoroughbred racehorse.  相似文献   

Frontal Septation of the Bladder in a Mare     

Brett A. Sponseller  Rebecca McElhaney  Gary P. Carlson  Tom B. Yarbrough  Samia Z. Macon 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1998,12(4):313-315

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OPPORTUNITIES IN ANTHROPOLOGY AT THE WORLD'S FAIR     

McGee WJ 《Science (New York, N.Y.)》1904,20(503):253-254

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Man and the Glacial Period     

McGee WJ 《Science (New York, N.Y.)》1892,20(513):317

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CLIMATOLOGY OF TINAJAS ALTAS,ARIZONA: PRELIMINARY REPORT     

McGee WJ 《Science (New York, N.Y.)》1906,23(593):721-730

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Litter dynamics of six multipurpose trees in a homegarden in Southern Kerala, India     

Sheeba Rebecca Isaac  M. Achuthan Nair 《Agroforestry Systems》2006,67(3):203-213

Multipurpose trees, the integral components of homegardens, contribute significantly to the closed nutrient cycling processes and sustainability of the ecosystem. Although, the litter production and probable nutrient returns via litter in homegardens have been documented, quantification and characterization of the decomposition and bioelement release from the litter have received relatively little scientific attention. The objective of the present study is to explore the litter dynamics of six locally important multipurpose trees (Mangifera indica L., Artocarpus heterophyllus Lamk., Anacardium occidentale L., Ailanthus triphysa Dennst., Artocarpus hirsutus L. and Swietenia macrophylla L.), in an agroforestry homegarden in Southern Kerala, India. Litterfall and nutrient additions in the six species ranged from 383 to 868 g m⁻² yr⁻¹, nitrogen, 6.4 to 8.8, phosphorus, 0.17 to 0.42 and potassium, 1.1 to 2.8 g m⁻² yr⁻¹. The annual litter output in the homegarden was 425 kg with A. hirsutus, M. indica, A. heterophyllus and A. occidentale recording significantly higher litter and nutrient additions. Leaf litter decay studies revealed A. heterophyllus and A. occidentale to be the most labile litter species and S. macrophylla the most recalcitrant. The decay rate coefficients varied significantly among the species. Foliage decomposition rates related to the initial chemical composition of the litter revealed best correlation with lignin. NPK release was almost complete by the end of decay in all species inspite of the initial phases of accumulation observed for nitrogen and phosphorus. Two-way analysis of variance test revealed significant differences in the contents of the three elements as a function of species and time elapsed. Macronutrients were released in the order K>N/P. The higher rates of decay and nutrient turnover in M. indica, A. heterophyllus and A. occidentale foliage indicated the potential of using these species’ litter as nutrient inputs in agriculture while A. triphysa, A. hirsutus and S. macrophylla perform better as organic mulches taking a longer time for decay and hence nutrient release.  相似文献   

ASSESSMENT OF RESPIRATION‐INDUCED DISPLACEMENT OF CANINE ABDOMINAL ORGANS IN DORSAL AND VENTRAL RECUMBENCY USING MULTISLICE COMPUTED TOMOGRAPHY          下载免费PDF全文

Cintia R. Oliveira  Margaret A. Henzler  Rebecca A. Johnson  Randi Drees 《Veterinary radiology & ultrasound》2015,56(2):133-143

Respiratory‐induced organ displacement during image acquisition can produce motion artifacts and variation in spatial localization of an organ in diagnostic computed tomography (CT) examinations. The purpose of this prospective study was to quantify respiratory‐induced abdominal organ displacement in dorsal and ventral recumbency using five normal dogs. All dogs underwent CT examinations using 64 multidetector row CT (64‐MDCT). A “3‐dimensional (3D) apneic CT exam” of the abdomen was acquired followed by a “4‐dimensional (4D) ventilated CT exam.” The liver, pancreas, both kidneys, both medial iliac lymph nodes, and urinary bladder were delineated on the 3D‐apneic examination and the organ outlines were compared to the maximum alteration in organ position in the 4D‐ventilated examination. Displacement was measured in dorsal‐to‐ventral (DV), right‐to‐left (RL), and cranial‐to‐caudal (CC) directions. Respiratory‐induced displacement of canine abdominal organs was not predictable and showed large variability in the three directions evaluated. For most canine abdominal organs, dorsal recumbency provided overall the least amount of displacement among all directions evaluated except for liver and urinary bladder. For liver, a large variability was found for all directions and a statistically significant difference was found only in the RL direction with ventral recumbency exhibiting less displacement (P = 0.0099). For the urinary bladder, ventral recumbency also provided less displacement but this was statistically significant only in the RL direction (P < 0.0001). Findings from this study indicated that dorsal recumbency may be preferred for minimizing respiratory motion artifacts in whole abdomen studies, but ventral recumbency may be preferred for liver and urinary bladder studies when respiration cannot be controlled.  相似文献