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Haeffel Gerald J.; Abramson Lyn Y.; Voelz Zachary R.; Metalsky Gerald I.; Halberstadt Lisa; Dykman Benjamin M.; Donovan Patricia; Hogan Michael E.; Hankin Benjamin L.; Alloy Lauren B. 《Canadian Metallurgical Quarterly》2005,5(3):343
Results from studies using a behavioral high-risk design and approximations to it generally have corroborated the cognitive vulnerability hypothesis of depression, whereas results from remitted depression studies typically have not. Suspecting that design features of previously conducted remitted designs likely precluded them from detecting maladaptive cognitive patterns, the authors conducted a study featuring the remitted design that has been successful in studies of a biological vulnerability for depression. Participants' current depressive symptoms, negative cognitive styles (hopelessness theory), dysfunctional attitudes (Beck's theory), and lifetime prevalence of clinically significant depression were assessed. Participants who had remitted from an episode of clinically significant depression had more negative cognitive styles, but not greater levels of dysfunctional attitudes, than did never depressed individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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The effect of regulated flow regimentation on hydrogeomorphological variables, autochthonous and allochthonous trophic sources and macroinvertebrates communities of the Mucone River, Calabria (Italy) were studied in May, August and November 2005 at three study sites. The first site (M1) was located close to the impoundment, the second one (M2) immediately upstream from the first permanent tributary (Cerreto stream) and the third one (M3) about 1 km downstream from the Cerreto confluence. Our results suggest that hydrogeomorphological gradients already exist in spring but their strongest development, with major consequences for the lotic biota, take place only with the beginning and ending of the dry season. Reduction of river width, shading due to well preserved riparian alder trees and marked sand deposition in November, were the variables negatively affecting epilithic microalgae biomass at site M1. These factors partially relieved at M2 site and became much less important at M3 resulting in the highest levels of autotrophic periphyton production. Coarse particulate organic matter accumulation exhibited an opposite trend due to the lack of discharge peaks at M1, whereas in November, litter fall removed most differences between stations. In May macrozoobenthic communities of the three stations were relatively similar (reophilous gatherer and scraper taxa). In November sand accumulation reduced spatial heterogeneity and habitats density close to the Cecita dam promoting settlement of shredder sand tolerant taxa (Plecoptera: Leuctridae) and a drop of community biodiversity. Flow reactivation, especially after Cerreto confluence, hindered sand accumulation, favoured autochthonous primary production and increased energy sources for macroinvertebrates. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Schulz TJ Voelz DG 《Journal of the Optical Society of America. A, Optics, image science, and vision》2005,22(4):616-624
A signal recovery technique is motivated and derived for the recovery of several nonnegative signals from measurements of their autocorrelation and cross-correlation functions. The iterative technique is shown to preserve nonnegativity of the signal estimates and to produce a sequence of estimates whose correlations better approximate the measured correlations as the iterations proceed. The method is demonstrated on simulated data for active imaging with dual-frequency or dual-polarization illumination. 相似文献
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Estimation of laser system pointing performance by use of statistics of return photons 总被引:1,自引:0,他引:1
Strategic laser systems are subject to residual pointing errors arising from vibrations and atmospheric turbulence, estimates of which may allow improved system performance. Field data from the Air Force Research Laboratory Floodbeam Experiments suggested a linear relationship between the mean and standard deviation of the shot-by-shot signals and the jitter. An ideal analytic solution and Monte Carlo simulations confirmed this result for a relatively large number of returns. A refined approach using statistical chi(2) techniques, which simultaneously estimates jitter and boresight, was developed to address results from satellite passes with relatively few returns and provides excellent jitter and boresight predictions. 相似文献
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J.S. Stevenson J.A. Sauls L.G.D. Mendonça B.E. Voelz 《Journal of dairy science》2018,101(10):9575-9590
We hypothesized (1) that neither duration of the Ovsynch program nor dose frequency of PGF2α would change the proportion of cows with complete luteolysis (progesterone <0.4 ng/mL 72 h after PGF2α) and (2) that the additional GnRH treatment administered as part of a presynchronization program would not alter the proportion of anovulatory cows starting the timed artificial insemination (AI) program compared with an alternative shorter presynch program including only 1 GnRH treatment. Lactating Holstein cows (n = 406) were milked 3 times daily and enrolled in a 2 × 2 × 2 factorial experiment consisting of 8 treatments before the first postpartum AI. Treatments were used to test ovulatory, luteal, and luteolytic outcomes to 3 main effects: (1) 2 GnRH-PGF2α presynchronization programs (PG-3-G vs. Double Ovsynch), (2) 2 Ovsynch program durations [5 d: GnRH (GnRH-1)–5 d–PGF2α–24 h–PGF2α–32 h–GnRH (GnRH-2)–16 h–timed AI; 7 d: GnRH-1–7 d–PGF2α–56 h–GnRH-2–16 h–timed AI], and (3) 2 PGF2α dose frequency treatments (2 × 25 mg) 24 h apart versus 1 dose (1 × 50 mg) of PGF2α administered 72 h before timed AI. The presynchronization treatments of PG-3-G and Double Ovsynch had no effect on the proportion of cows with luteal function at the onset of the Ovsynch treatments (87.9 vs. 86.2%). Although ovulatory responses were similar after GnRH-1 (>60%), Double Ovsynch cows tended to have greater ovulatory responses than PG-3-G after GnRH-2 (95.3 vs. 90.6%). The 2 × 25-mg doses of PGF2α and the 1 × 50-mg dose induced luteolysis in both Ovsynch treatment durations, but the 1 × 50-mg dose was less effective in the 5-d program. More pregnancy per AI (P/AI; 49.2%) tended to occur in the PG-3-G cows in the 7-d program compared with the other treatment combinations (range: 32.4–37.4%; Ovsynch × presynch interaction). In addition, an Ovsynch × PGF2α dose frequency interaction resulted in cows receiving the 1 × 50-mg dose in the 7-d program having the greatest P/AI (46.1%) and cows receiving the 1 × 50-mg dose in the 5-d program having the least P/AI (30.6%). We conclude that complete luteolysis was less effective in the 5-d program when the 1 × 50-mg dose was applied, but both PGF2α dose frequencies (1 × 50 mg and 2 × 25 mg 24 h apart) effectively induced complete luteolysis in the 7-d program. Treatments producing complete luteolysis tended to be related to subsequent pregnancy outcomes. 相似文献
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At what age and in what ways do children distinguish deductive and inductive problems? In Exp 1, students from kindergarten and from Grades 2, 4, and 6 were presented with deductive or inductive inference problems and asked to draw an inference and rate their confidence. By 4th grade, confidence ratings for deductive problems were higher than those for inductive problems, and responses were faster for deductive than for inductive items. In Exp 2, students from Grades 2, 3, 4, and 5 responded to the same problems used in Exp 1 but were asked to provide explanations for their responses. Again, confidence was higher with deductive than with inductive problems, and latency to respond was faster for deductive than for inductive items. Further, explanations differed as a function of the type of problem. These findings help fill in gaps in the emerging picture of the development of children's reasoning skills. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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J.A. Sauls B.E. Voelz S.L. Hill L.G.D. Mendonça J.S. Stevenson 《Journal of dairy science》2017,100(1):807-820
Using an activity monitoring system (AMS) equipped with an accelerometer, 2 experiments were conducted to test the hypotheses that (1) enhancing progesterone before inducing luteolysis or (2) exposing cows to estradiol cypionate (ECP) or testosterone propionate (TP) after luteolysis would increase occurrence and intensity of estrus. Our goal was to determine if more cows could be detected in estrus by an AMS compared with other estrus-detection aids. In experiment 1, cows (n = 154) were fitted with both an AMS collar and a pressure-sensitive, rump-mounted device (HeatWatch; HW) and assigned to 3 treatments: (1) no CL + progesterone insert (CIDR) for 5 d, (2) CL only, or (3) CL + 2 CIDR inserts for 5 d to achieve a range in concentrations of progesterone. Prostaglandin F2α was administered to all cows upon CIDR insert removal or its equivalent. Progesterone concentration up to 72 h posttreatment was greatest in CL + 2 CIDR, followed by CL only, and no CL + CIDR cows. Estrus occurred 14 to 28 h earlier in no CL + CIDR compared with CL-bearing cows. Estrus intensity was greater for CL + 2 CIDR than for CL-only cows. The AMS and HW detected 70 and 59% of cows defined to be in estrus, respectively. In experiment 2, cows (n = 203) were equipped with both an AMS and a friction-activated, rump-mounted patch (Estrotect patch) and assigned to receive 1 mg of ECP, 2 mg of TP, or control 24 h after PGF2α. Concentrations of estradiol 24 and 48 h after treatment were greater in ECP cows compared with controls. Estrus expression detected by AMS or patches in cows defined to be in estrus tended to be greater or was greater for ECP compared with controls, respectively. Compared with controls and in response to TP or ECP, estrus occurred 8 to 18 h earlier and was of greater intensity for ECP cows, respectively. The AMS and patches determined 73 and 76% of cows defined to be in estrus, respectively. Of cows exposed to the AMS, HW, or patches, 70, 61, and 75%, respectively, were detected in estrus and more than 93% of these subsequently ovulated. In contrast, of the residual cows not detected in estrus, 62 to 77% ovulated in the absence of detected estrus. Only ECP was successful in inducing more expression and intensity of estrus, and proportions of cows detected in estrus exceeded 80%. Given the large proportion of cows equipped with AMS collars ovulating in the absence of estrus, further research is warranted to determine if more pregnancies can be achieved by inseminating those cows not detected in estrus at an appropriate time when PGF2α is administered to induce luteolysis. 相似文献
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Polarization-based index of refraction and reflection angle estimation for remote sensing applications 总被引:3,自引:0,他引:3
A passive-polarization-based imaging system records the polarization state of light reflected by objects that are illuminated with an unpolarized and generally uncontrolled source. Such systems can be useful in many remote sensing applications including target detection, object segmentation, and material classification. We present a method to jointly estimate the complex index of refraction and the reflection angle (reflected zenith angle) of a target from multiple measurements collected by a passive polarimeter. An expression for the degree of polarization is derived from the microfacet polarimetric bidirectional reflectance model for the case of scattering in the plane of incidence. Using this expression, we develop a nonlinear least-squares estimation algorithm for extracting an apparent index of refraction and the reflection angle from a set of polarization measurements collected from multiple source positions. Computer simulation results show that the estimation accuracy generally improves with an increasing number of source position measurements. Laboratory results indicate that the proposed method is effective for recovering the reflection angle and that the estimated index of refraction provides a feature vector that is robust to the reflection angle. 相似文献