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We examine poverty's effect in two ways. First, we study the relationship between poverty and capacity for innovation in the U.S. states; second, we study the combined effects of poverty and innovation capacity on U.S. state economic output and employment. Because many of the relationships among poverty, innovation capacity and economic performance are simultaneous, we employ the Arellano Bond Difference GMM estimator to estimate various models using panel data (1980–1999). The findings reveal a negative indirect effect of socio‐economic need (poverty) on human and U.S. state and local financial innovation capacity, though there is no empirical link between poverty and federal financial capacity. We find no statistically significant evidence of the contemporaneous effect of poverty on state economic performance, holding innovation capacity constant. This suggests that poverty primarily affects state economic performance indirectly through reduction of innovation capacity. Overall, our findings suggest that U.S. officials ought to be concerned about the role poverty plays in diminishing their state economies' capacity to innovate.  相似文献   
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Objective— To report management of a chronic slipped capital femoral epiphysis (SCFE) in an alpaca using cementless total hip replacement (THR).
Study Design— Case report.
Animal— An 18-month-old, 47 kg alpaca male.
Methods— Cementless THR was performed in an alpaca with a chronic, right SCFE, and secondary osteoarthritis. Force plate gait analysis was performed before and 8 weeks after surgery. Outcome was determined through clinical evaluation, radiography, and force plate gait analysis.
Results— Cementless THR resulted in marked improvement in the alpaca's comfort level, degree of lameness, and range of motion. On preoperative force plate gait analysis there was decreased contact time ( P =.01) and vertical impulse ( P <.01) of the affected limb, whereas at 8 weeks postoperatively significant differences in gait analysis between pelvic limbs were not apparent.
Conclusion— THR using a BioMedtrix® canine cementless modular prosthesis restored hip function in an alpaca with coxofemoral osteoarthritis from chronic SCFE.
Clinical Relevance— THR may be an appropriate treatment for selected traumatic and degenerative conditions of the coxofemoral joint in alpacas.  相似文献   
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Objectives— To compare in vitro monotonic biomechanical properties of an axial 3‐hole, 4.5 mm narrow dynamic compression plate (DCP) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion (DCP‐TLS) with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion (3‐TLS) for the equine proximal interphalangeal (PIP) joint arthrodesis. Study Design— Paired in vitro biomechanical testing of 2 methods of stabilizing cadaveric adult equine forelimb PIP joints. Sample Population— Cadaveric adult equine forelimbs (n=15 pairs). Methods— For each forelimb pair, 1 PIP joint was stabilized with an axial 3‐hole narrow DCP (4.5 mm) using 5.5 mm cortical screws in conjunction with 2 abaxial transarticular 5.5 mm cortical screws inserted in lag fashion and 1 with 3 parallel transarticular 5.5 mm cortical screws inserted in lag fashion. Five matching pairs of constructs were tested in single cycle to failure under axial compression, 5 construct pairs were tested for cyclic fatigue under axial compression, and 5 construct pairs were tested in single cycle to failure under torsional loading. Mean values for each fixation method were compared using a paired t‐test within each group with statistical significance set at P<.05. Results— Mean yield load, yield stiffness, and failure load under axial compression and torsion, single cycle to failure, of the DCP‐TLS fixation were significantly greater than those of the 3‐TLS fixation. Mean cycles to failure in axial compression of the DCP‐TLS fixation was significantly greater than that of the 3‐TLS fixation. Conclusion— The DCP‐TLS was superior to the 3‐TLS in resisting the static overload forces and in resisting cyclic fatigue. Clinical Relevance— The results of this in vitro study may provide information to aid in the selection of a treatment modality for arthrodesis of the equine PIP joint.  相似文献   
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Goosegrass (Eleusine indica), regarded as one of the world's worst weeds, is highly pernicious to cash crop‐growers in Malaysia. Following reports in 2009 that glufosinate‐ammonium failed to adequately control goosegrass populations in Kesang, Malacca, and Jerantut, Pahang, Malaysia, on‐site field trials were conducted to assess the efficacy of glufosinate‐ammonium towards goosegrass in both places. Preliminary screenings with glufosinate‐ammonium at the recommended rate of 495 g ai ha?1 provided 82% control of the weed at a vegetable farm in Kesang, while the same rate failed to control goosegrass at an oil palm nursery in Jerantut. The ensuing greenhouse evaluations indicated that the “Kesang” biotype exhibited twofold resistance, while the “Jerantut” biotype exhibited eightfold resistance towards glufosinate‐ammonium, compared to susceptible goosegrass populations. The occurrence of glufosinate resistance in goosegrass calls for more integrated management of the weed to prevent escalating resistance and further proliferation of the weed in Malaysia.  相似文献   
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Patterns of population variability in marine fish stocks   总被引:3,自引:0,他引:3  
Exploited marine fish and invertebrate stocks fluctuate in a myriad of complex patterns, exhibiting variability on interannual, decadal, and longer time scales. To characterize various patterns of variation, time series of catch, catch per unit effort, or biomass from 30 stocks were examined with a variety of statistical methods including autocorrelation analysis and Lowess smoothing. A hierarchical cluster analysis classified the stocks into six identifiable groups: steady-state; low-variation, low-frequency; cyclic; irregular; high-variation, high-frequency; and spasmodic. The observed patterns are consistent with life history traits; for example, stocks with high variability are generally small, pelagic species whereas low-variability stocks are generally slow-growing, demersal fish. Each of the six general patterns of variability can be produced from a simple multiple-equilibrium population model by varying the intrinsic rate of population growth, and the time scale and amplitude of environmental variability. Suitable management policies depend on the type of variation observed, and the vast majority of stocks examined do not correspond to the steady-state assumptions of classical fisheries models. For example, management of spasmodic stocks may alternate between periods of active exploitation and periods of rebuilding, a process enhanced by the existence of alternative fisheries.  相似文献   
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