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排序方式: 共有622条查询结果,搜索用时 15 毫秒
51.
Grady Cheryl L.; Bernstein Lori J.; Beig Sania; Siegenthaler Amy L. 《Canadian Metallurgical Quarterly》2002,17(1):7
Age-related differences in brain activity mediating face recognition were examined using positron emission tomography. Participants encoded faces using a pleasant-unpleasant judgement, a right-left orientation task, and intentional learning. Scans also were obtained during recognition. Both young and old groups showed significant effects of encoding task on recognition accuracy, but older adults showed reduced accuracy overall. Increased brain activity in older adults was similar to that seen in young adults during conditions associated with deeper processing, but was reduced during the shallow encoding and recognition conditions. Differential correlations of brain activity and behavior were found that suggest older adults use unique neural systems to facilitate face memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
53.
Lori N. Ivan Edward S. Rutherford Catherine Riseng Jeffrey A. Tyler 《Journal of Great Lakes research》2010
Walleye (Sander vitreus) is an important sport fish in the Great Lakes that is experiencing low reproductive success after severe population declines starting in the late 1940s. In the Muskegon River, Michigan, natural reproduction of walleyes remains low and is largely supplemented by stocking. To determine factors influencing walleye reproductive success in the Muskegon River, we estimated walleye egg survival using insitu egg incubators covered with nitex screening (2003–2004) and estimated density and survival of fertilized eggs caught on furnace filter traps across different substrate types (2005–2006). We compared physical habitat suitability for walleye eggs under high and low flow scenarios. Density of walleye eggs was highest in regions of gravel/cobble substrates. Egg survival was higher in egg incubators (24–49.5%) than on furnace filter traps (2.0%), suggesting predation is an important source of walleye egg mortality in the Muskegon River. Cold water temperatures that extended developmental stage durations may also be an important source of egg mortality. The dynamic habitat suitability model predicted low suitability for eggs due to poor temperature and velocity conditions. Despite low egg survival rates, 40 million to 1 billion eggs were estimated to hatch. The low natural reproduction of walleyes in the Muskegon River is likely due to a combination of low walleye egg survival and failure of walleye larvae to reach their nursery grounds in Muskegon Lake. 相似文献
54.
Robert S. Janesheski Lori J. Groven Steven F. Son 《Propellants, Explosives, Pyrotechnics》2014,39(4):609-616
Typically characterizing home made explosives (HMEs) requires many large scale experiments, which is prohibitive given the large number of materials in use. A small scale experiment was developed to characterize HMEs such as ammonium nitrate‐fuel oil mixtures. A microwave interferometer is applied to small scale confined transient experiments, yielding time resolved characterization of a failing detonation that is initiated with an ideal explosive booster charge. Experiments were performed with ammonium nitrate and two fuel compositions (diesel fuel and mineral oil). It was observed that the failure dynamics were influenced by factors such as the chemical composition, confiner thickness, and applied shock wave strength. Thin steel walled confiners with 0.71 mm wall thickness experienced detonation failure and decoupling of the shock wave from the reaction zone. Confiners with a wall thickness of 34.9 mm showed a decrease in propagation speed and a steady reactive wave was achieved. Varying the applied shock strength by using an attenuator showed corresponding changes in the initial overdriven reactive wave velocity in the HMEs. The distance to detonation failure was also shown to depend on the attenuator length when thin wall confinement was used. This experimental method is shown to be repeatable and can be performed with little required material (about 2 g). The data obtained could be useful to model development and validation, as well as quantifying detonability of materials. 相似文献
55.
David A. Reese Steven F. Son Lori J. Groven 《Propellants, Explosives, Pyrotechnics》2014,39(5):684-688
Composite propellants based on the solid nitrate ester 2,3‐hydroxymethyl‐2,3‐dinitro‐1,4‐butanediol tetranitrate (SMX) were theoretically and experimentally examined and compared to formulations based on ammonium perchlorate (AP). Thermochemical equilibrium calculations show that aluminized SMX‐based formulations can achieve theoretical sea level specific impulse values upwards of 260 s. Both ignition sensitivity (tested via drop weight impact, electrostatic discharge, and BAM friction) and physical properties (hardness and thermal properties) are comparable to those of the AP‐based formulations. However, the SMX‐based formulation could be detonated using a high explosive donor charge in contact with the propellant. Differential scanning calorimetry of the SMX‐based propellant indicated an exotherm onset of 140 °C, which corresponds to the known decomposition temperature of SMX. The propellant has a high burning rate of 1.57 cm s−1 at 6.89 MPa, with a pressure exponent of 0.85. This high pressure sensitivity might be addressed using various energetic and/or stabilizing additives. With good performance and high density, SMX‐based composite propellants may offer a promising perchlorate‐free alternative to existing AP‐based formulations. 相似文献
56.
Lori E. Lowes Scott V. Bratman Ryan Dittamore Susan Done Shana O. Kelley Sabine Mai Ryan D. Morin Alexander W. Wyatt Alison L. Allan 《International journal of molecular sciences》2016,17(9)
Despite the identification of circulating tumor cells (CTCs) and cell-free DNA (cfDNA) as potential blood-based biomarkers capable of providing prognostic and predictive information in cancer, they have not been incorporated into routine clinical practice. This resistance is due in part to technological limitations hampering CTC and cfDNA analysis, as well as a limited understanding of precisely how to interpret emergent biomarkers across various disease stages and tumor types. In recognition of these challenges, a group of researchers and clinicians focused on blood-based biomarker development met at the Canadian Cancer Trials Group (CCTG) Spring Meeting in Toronto, Canada on 29 April 2016 for a workshop discussing novel CTC/cfDNA technologies, interpretation of data obtained from CTCs versus cfDNA, challenges regarding disease evolution and heterogeneity, and logistical considerations for incorporation of CTCs/cfDNA into clinical trials, and ultimately into routine clinical use. The objectives of this workshop included discussion of the current barriers to clinical implementation and recent progress made in the field, as well as fueling meaningful collaborations and partnerships between researchers and clinicians. We anticipate that the considerations highlighted at this workshop will lead to advances in both basic and translational research and will ultimately impact patient management strategies and patient outcomes. 相似文献
57.
J. C. Wakefield's (1999) elaboration of his harmful dysfunction analysis (HDA) of mental disorder does little to address previous criticisms (S. O. Lilienfeld & L. Marino, 1995) and instead reveals further conceptual weaknesses in his position. The authors demonstrate that (a) a Roschian analysis can account for the results of all of Wakefield's conceptual experiments and predicts a number of judgments of disorder not predicted by the HDA, (b) the HDA is incapable in many cases of providing a scientifically nonarbitrary distinction between disorder and nondisorder, and (c) the HDA cannot account for failures of cultural exaptations, mismatches between evolutionary design and novel environments, or defenses against threat. The authors argue that the HDA has been convincingly falsified and discuss the failure of essentialistic concepts to resolve controversies in other domains of biological science. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
58.
This review of four usage-modeling techniques clarifies key elements of each technique and their strengths and weaknesses from the perspective of usage-centered development. It also points to tools where appropriate. Finally, the authors argue for applying a template-supported use scenario integrating the three approaches. 相似文献
59.
The beneficial effect of dispersions of reactive-metal oxide particles on the adhesion of Cr2O3 and Al2O3 scales formed on heat-resisting alloys is wellknown. It has been shown that an Al2O3 dispersion in an alloy can improve the adhesion of a Cr2O3 scale, and it is of particular interest in assessing the various theoretical proposals for the effect to determine whether such a dispersion can affect the adhesion of an Al2O3 scale. In this investigation, a Co–10% Cr–1 % Al alloy was first internally oxidized to form an Al2O3 dispersion. This alloy was then aluminized so that on subsequent oxidation an Al2O3 scale developed. It was shown that the dispersion did indeed improve the scale adhesion. The implications of this result are discussed. 相似文献
60.
Katz Lori S.; Snetter Miatta R.; Robinson Athena Hagler; Hewitt Paul; Cojucar Geta 《Canadian Metallurgical Quarterly》2008,45(2):186
Holographic reprocessing (HR) facilitates holistic reappraisal of attributions regarding interpersonal violence and maltreatment. The authors tested the feasibility to train therapists to run a protocol using HR to reduce negative thoughts associated with posttraumatic stress disorder (PTSD) in women veterans who have had sexual trauma or abuse. The study assessed pre- and postscores on the Posttraumatic Cognitions Inventory (PTCI) in a naturalistic clinical setting with 5 therapists. The protocol consisted of screening for PTSD, followed by an average of 9 HR treatment sessions. Twenty-two women were referred to the study; 17 enrolled and completed treatment (0% dropout rate). Significant decreases were found on all scales of the PTCI, with large effect sizes: total negative thoughts, t(16) = 4.42, p 相似文献