2,820 research outputs found
Characteristics of Cressbred Progeny of Holstein Dams Sired by Different Beef Breeds: A Review
Excellent reviews of cattle breed comparisons or breed-cross comparisons have been previously reported by Franke (1980), Long (1980), and Marshall (1994). However, these reviews do not contain information on the calving ease, performance, carcass characteristics, or beef palatability of crossbred progeny of Holstein dams sired by different beef breeds. In many countries dairy females are commonly mated to beef sires; however, in the United States the use of this practice is somewhat limited. Nevertheless, some United States dairy production schemes utilize beef sires on surplus Holstein heifers and cows. Also, some large commercial dairy operations purchase replacement heifers from outside entities, thus permitting optional breeding schemes for some dairy females in their herds. Finally, in the near future, information on crossbred progeny of Holstein dams sired by different beef breeds could become particularly useful if semen and embryo sexing technology becomes practical, allowing for selective matings to generate dairy replacement heifers, thereby freeing other Holstein females to produce terminal progeny. From a genetic and economic standpoint, the crossing of beef bulls to Holstein females could result in improved utilization of existing genetics and an untapped alternative source of business for beef and dairy producers alike. Therefore, the purpose of this review is to 1) compare the birth, weaning, feedlot, and carcass characteristics of progeny from the matings of Holstein females with different beef sire breeds and 2) suggest possible research needs that warrant further consideration
The Forward Testing Effect: Interim Testing Enhances Inductive Learning.
Induction refers to the process in which people generalize their previous experience when making uncertain inferences about the environment that go beyond direct experience. Here we show that interim tests strongly enhance inductive learning. Participants studied the painting styles of eight famous artists across four lists, each comprising paintings by one pair of artists. In an interim test group participants’ induction was tested after each list. In two control groups participants solved math problems (interim math group) or studied additional new paintings (interim study group) following each of Lists 1–3 and were asked to classify new paintings on List 4. In the List 4 interim test, the interim test group significantly outperformed the other two groups, indicating that interim testing enhances new inductive learning. In a final cumulative test, accuracy in the interim test group at classifying new paintings by studied artists was nearly double that of the other two groups, indicating the major importance of interim testing in inductive learning. This enhancing effect of interim testing on inductive learning was associated with metacognitive awareness
An effect of age on implicit memory that is not due to explicit contamination: implications for single and multiple-systems theories
Recognition memory is typically weaker in healthy older relative to young adults, while performance on implicit tests (e.g., repetition priming) is often comparable between groups. Such observations are commonly taken as evidence for independent explicit and implicit memory systems. On a picture version of the continuous identification with recognition (CID-R) task, we found a reliable age-related reduction in recognition memory, while the age effect on priming did not reach statistical significance (Experiment 1). This pattern was consistent with the predictions of a formal single-system model. Experiment 2 replicated these observations using separate priming (continuous identification; CID) and recognition phases, while a combined data analysis revealed a significant effect of age on priming. In Experiment 3, we provide evidence that priming in this task is unaffected by explicit processing, and we conclude that the age difference in priming is unlikely to have been driven by differences in explicit processing between groups of young and older adults (“explicit contamination”). The results support the view that explicit and implicit expressions of memory are driven by a single underlying memory system
Does study duration have opposite effects on recognition and repetition priming?
We investigated whether manipulating the duration for which an item is studied has opposite effects on recognition memory and repetition priming, as has been reported by Voss and Gonsalves (2010). Robust evidence of this would support the idea that distinct explicit and implicit memory systems drive recognition and priming, and would constitute evidence against a single-system model (Berry, Shanks, Speekenbrink, & Henson, 2012). Across seven experiments using study durations ranging from 40 ms to 2250 ms, and two different priming tasks (a classification task in Experiments 1a, 2a, 3a, and 4, and a continuous identification with recognition (CID-R) task in Experiments 1b, 2b, and 3b), we found that although a longer study duration improved subsequent recognition in each experiment, there was either no detectable effect on priming (Experiments 1a, 2a, and 4) or a similar effect to that on recognition, albeit smaller in magnitude (Experiments 1b, 2b, 3a, and 3b). Our findings (1) question whether study duration has opposite effects on recognition and priming, and (2) are robustly consistent with a single-system model of recognition and priming
Age effects on explicit and implicit memory
It is well-documented that explicit memory (e.g., recognition) declines with age. In contrast, many argue that implicit memory (e.g., priming) is preserved in healthy aging. For example, priming on tasks such as perceptual identification is often not statistically different in groups of young and older adults. Such observations are commonly taken as evidence for distinct explicit and implicit learning/memory systems. In this article we discuss several lines of evidence that challenge this view. We describe how patterns of differential age-related decline may arise from differences in the ways in which the two forms of memory are commonly measured, and review recent research suggesting that under improved measurement methods, implicit memory is not age-invariant. Formal computational models are of considerable utility in revealing the nature of underlying systems. We report the results of applying single and multiple-systems models to data on age effects in implicit and explicit memory. Model comparison clearly favors the single-system view. Implications for the memory systems debate are discussed
Noise measurements for a twin-engine commercial jet aircraft during 3 deg approaches and level flyovers
Noise measurements have been made with a twin-engine commercial jet aircraft making 3 deg approaches and level flyovers. The flight-test data showed that, in the standard 3 deg approach configuration with 40 deg flaps, effective perceived noise level (EPNL) had a value of 109.5 effective perceived noise decibels (EPNdB). This result was in agreement with unpublished data obtained with the same type of aircraft during noise certification tests; the 3 deg approaches made with 30 deg flaps and slightly reduced thrust reduced the EPNL value by 1 EPNdB. Extended center-line noise determined during the 3 deg approaches with 40 deg flaps showed that the maximum reference A-weighted sound pressure level (LA,max)ref varied from 100.0 A-weighted decibels 2.01 km (108 n. mi.) from the threshold to 87.4 db(A) at 6.12 km (3.30 n. mi.) from the threshold. These test values were about 3 db(A) higher than estimates used for comparison. The test data along the extended center line during approaches with 30 deg flaps were 1 db(A) lower than those for approaches with 40 deg flaps. Flight-test data correlating (LA,max)ref with thrust at altitudes of 122 m (400 ft) and 610 m (2000 ft) were in agreement with reference data used for comparison
Spatial Correlation Function of X-ray Selected AGN
We present a detailed description of the first direct measurement of the
spatial correlation function of X-ray selected AGN. This result is based on an
X-ray flux-limited sample of 219 AGN discovered in the contiguous 80.7 deg^2
region of the ROSAT North Ecliptic Pole (NEP) Survey. Clustering is detected at
the 4 sigma level at comoving scales in the interval r = 5-60 h^-1 Mpc. Fitting
the data with a power law of slope gamma=1.8, we find a correlation length of
r_0 = 7.4 (+1.8, -1.9) h^-1 Mpc (Omega_M=0.3, Omega_Lambda=0.7). The median
redshift of the AGN contributing to the signal is z_xi=0.22. This clustering
amplitude implies that X-ray selected AGN are spatially distributed in a manner
similar to that of optically selected AGN. Furthermore, the ROSAT NEP
determination establishes the local behavior of AGN clustering, a regime which
is poorly sampled in general. Combined with high-redshift measures from optical
studies, the ROSAT NEP results argue that the AGN correlation strength
essentially does not evolve with redshift, at least out to z~2.2. In the local
Universe, X-ray selected AGN appear to be unbiased relative to galaxies and the
inferred X-ray bias parameter is near unity, b_X~1. Hence X-ray selected AGN
closely trace the underlying mass distribution. The ROSAT NEP AGN catalog,
presented here, features complete optical identifications and spectroscopic
redshifts. The median redshift, X-ray flux, and X-ray luminosity are z=0.41,
f_X=1.1*10^-13 cgs, and L_X=9.2*10^43 h_70^-2 cgs (0.5-2.0 keV), respectively.
Unobscured, type 1 AGN are the dominant constituents (90%) of this soft X-ray
selected sample of AGN.Comment: 17 pages, 8 figures, accepted for publication in ApJ, a version with
high-resolution figures is available at
http://www.eso.org/~cmullis/papers/Mullis_et_al_2004b.ps.gz, a
machine-readable version of the ROSAT NEP AGN catalog is available at
http://www.eso.org/~cmullis/research/nep-catalog.htm
The effectiveness of Lee Silverman Voice Treatment therapy issued interactively through an iPad device: a non-inferiority study.
Introduction This study compared the differences in recorded speech variables between people treated with conventional 'in person' Lee Silverman Voice Treatment (LSVT) and those treated remotely via iPad-based 'Facetime'. Method Eight participants were selected for the iPad LSVT, and 21 similarly matched subjects were selected from existing data to form the 'in person' group. Participants in both groups had diagnosed idiopathic Parkinson's disease and moderate hypokinetic dysarthria. Eighteen sessions of prescribed LSVT comprising a pre-treatment assessment, 16 treatment sessions, and a six months' post-treatment assessment were administered for each person. In both groups, pre- and post-treatment assessments were conducted face-to-face. Performance measures were recorded during assessment and treatment. Average measures were determined for all tasks at all time points and a summary outcome variable was composed from across-task performance. Results Non-inferiority testing confirmed that iPad LSVT was non-inferior in treating all LSVT task 3 variables except generating words, with the 90% upper confidence intervals (CI) lying between the non-inferiority margin of ± 2.25 and zero. The iPad was superior in treating the task 3 rainbow reading passage and describing motor task variables with upper and lower 90% CI values being negative. The improvement in the summary outcome variable score was also superior in the iPad group. Discussion Non-inferiority testing implies that the iPad LSVT is non-inferior in treating task three variables when compared to traditional LSVT. The study supports further development of remote delivery solutions involving the Apple iPad and 'Facetime' system as a means of improving access to services and the participant's experience
Instrumentation for a Postural Sway Platform
A postural sway platform has been developed for studies involving elderly falters. It will be used to assist in determining reasons some elderly people are prone to falling and others are not. Results of these postural sway tests will be combined with other tests on both fallers and nonfallers to determine specific reasons for falling. A simple Z-axis platform has been developed that utilizes a unique hanger system and three strain gage transducers. The output of these transducers is input to an analog-to-digital conversion board in a personal computer. Software has been written to take data from the platform and display it graphically on the computer screen. This display includes real-time information on the center of gravity of the patient, as well as his/her weight. Arithmetic means are then calculated on the accumulated sway pattern data. These results and the results of other tests on patients can then be used to determine if a patient may be prone to falling
Reduction behavior of potassium-promoted iron oxide under mixed steam/hydrogen atmospheres
Potassium-promoted iron oxide catalysts are used in large volume for the commercial ethylbenzene dehydrogenation to styrene process. Short-term deactivation of these catalysts, which is addressed by operating in excess steam, is thought to be caused due to reactive site loss through coking and/or reduction. However, the relative importance of the two mechanisms is not known. Presented are results concerning the reduction behavior of potassium-promoted iron oxide materials in the absence of carbon. Thermogravimetric experiments and X-ray diffraction analysis were used to examine the reduction behavior of potassium-promoted iron oxide materials. The reduction behavior was then compared with results from isothermal ethylbenzene dehydrogenation reactor studies under low steam-to-ethylbenzene operation. Potassium incorporation was found to stabilize the iron oxide against reduction apparently through the formation of KFeO 2. Chromium addition improved the reduction resistance, which gave good qualitative agreement with the dehydrogenation reaction studies. In contrast, vanadium incorporation led to more significant reduction as well as poor stability in the dehydrogenation reaction
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