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71.
Allison  J. Dawe  V.R. 《Electronics letters》1972,8(17):437-439
Many of the characteristics of threshold switching devices may be explained in terms of a simple space-charge-injection model if it is assumed that switching occurs at a critical electric-field strength. Experimental evidence to support this hypothesis is described.  相似文献   
72.
The surface reaction products formed when sulfide minerals react with xanthates were analyzed by spectrophotometric methods. These products were found to be predominantly either metal xanthate or dixanthogen, depending on the particular sulfide mineral. Dixanthogen is formed on those minerals that, in a solution of xanthate, assume a rest potential greater than the equilibrium potential for the reduction of dixanthogen or xanthate.  相似文献   
73.
Posttraumatic stress disorder (PTSD) is common among Veterans Affairs (VA) primary care patients and may be managed via multiple treatment pathways. Using the Behavioral Model of Health Service Use (Anderson, 1995), this retrospective study based on medical chart review examined factors associated with three types of mental health treatment: intervention by a 1) primary care provider (PCP), 2) primary care-mental health integration (PC-MHI) provider, and 3) specialty mental health (SMH) provider. A second goal was to describe PTSD treatment services for patients not receiving SMH by detailing the content of mental health treatment provided by PCPs and PC-MHI providers. Electronic medical record data for a five year time period for 133 Veterans were randomly selected for review from a population 6,637 primary care patients with PTSD. Results indicated that the evaluated needs of participants (i.e., number of unique medical and psychiatric disorders) were associated with Veterans receiving more intensive services (i.e., SMH). PCPs commonly addressed patients' mental health concerns, but patients often declined referrals for mental health treatment. PC-MHI consultations most often focused on medication management and supportive psychotherapy. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
74.
Interleukin (IL)-1 alpha and beta are cytokines which can mediate inflammatory, bone resorbing, and reparative effects in the periodontium, but few longitudinal data exist exploring their role following periodontal therapy. This study examined gingival crevicular fluid (GCF) concentrations of IL-1 alpha and IL-1 beta at sites with shallow sulci (SS) or inflamed moderate/advanced pockets (M/AP) before and 6 months after treatment with closed scaling/root planing (SC/RP) or papillary flap debridement (PFD), all in the same subject (n = 14 patients). No significant differences were noted in IL-1 alpha or beta concentrations (determined with two-site enzyme-linked immunosorbent assays) between SS and M/AP sites at baseline. While both therapies improved clinical parameters of periodontal disease, IL-1 alpha concentration increased significantly (p < 0.05) in M/AP-PFD sites 6 months after treatment, but were unchanged in other groups. IL-1 beta concentrations were numerically lower after therapy, except for a significant increase (p < 0.05) in M/AP-PFD sites. These data suggest that surgical wound healing in an inflamed, plaque-infected site (M/AP-PFD) results in prolonged production of IL-1, which may be a reflection of the extent of tissue trauma and delayed wound healing. In spite of increased IL-1 levels, these sites demonstrated significant short-term improvement in clinical attachment level (+ 1.8 mm, p < or = 0.001) postoperatively.  相似文献   
75.
76.
A basic question in EEG feedback training of epileptic patients is whether the decrease in seizures is specifically due to the training or to other factors. Questions may also be raised as to what EEG changes are involved. Preliminary results in five patients suggest that seizure reductions can occur with training which are not due to placebo or nonspecific effects or to changes in medication compliance. These changes occurred rapidly during EEG-contingent feedback training but not when feedback was random in relation to the EEG. Reliable changes in the EEG were also observed, but the question of which mechanism accounts for these results has yet to be answered.  相似文献   
77.
"Cures" embrace by definition a broad spectrum starting from taking waters in health resorts to hospital treatment in modern rehabilitation centers. The effectiveness of traditional cure procedures is discussed. Effectiveness of drinking cures, baths and mud packs in liver disease has not yet been proven. Controlled trials are necessary. Clinical treatment is indicated in alcoholic liver damage, viral hepatitis with a protracted course, chronic aggressive hepatitis and compensated cirrhosis of the liver; such treatment, however, is questionable in fatty liver and in chronic persistent hepatitis. Data concerning the effectiveness of treatment of chronic liver diseases are given. The following conclusions are drawn: patients with liver disease ought to be hospitalized when undergoing cures, indications have to be precised, collaboration of patients has to be stimulated, hospital discipline has to be tight, therapy of alcoholism has to include several psychosocial aspects, treatment after leaving hospital has to be improved.  相似文献   
78.
Focusing on a sample of nurses, this investigation examined the relationships of daily task accomplishment satisfaction (for direct and indirect care tasks) with changes in positive and negative affect from preshift to postshift. Not accomplishing tasks to one's satisfaction was conceptualized as a daily workplace stressor that should increase daily negative affect and decrease daily positive affect from preshift to postshift. Further, because of the greater centrality of direct care nursing tasks to nursing work role identities (relative to indirect care tasks), we expected that task accomplishment satisfaction (or lack thereof) for these tasks would have stronger effects on changes in affect than would task accomplishment satisfaction for indirect care tasks. We also examined 2 person-level resources, collegial nurse–physician relations and psychological resilience, as moderators of the relationships among these daily variables, with the expectation that these resources would buffer the harmful effects of low task accomplishment satisfaction on nurse affect. Results supported almost all of the proposed effects, though the cross-level interactions were observed only for the effects of indirect care task accomplishment satisfaction on affect and not for direct care task accomplishment satisfaction on affect. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
79.
Discusses 3 aspects of the problem of inferring information about nervous system function from evoked potential (EP) measurements: (1) electrogenesis of EPs, including their relation to the geometry of individual cells and cell groups; (2) effects of recording EPs from the scalp or body surface instead of directly from neural tissue; and (3) quantitative approaches to the problem of EP source localization. Primary emphasis is placed on the intimate relationship between EPs, anatomical structures, and physiological processes that give rise to them, and the properties of potential fields in conductive media. (French abstract) (86 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
80.
The authors describe 2 efficiency (planned missing data) designs for measurement: the 3-form design and the 2-method measurement design. The 3-form design, a kind of matrix sampling, allows researchers to leverage limited resources to collect data for 33% more survey questions than can be answered by any 1 respondent. Power tables for estimating correlation effects illustrate the benefit of this design. The 2-method measurement design involves a relatively cheap, less valid measure of a construct and an expensive, more valid measure of the same construct. The cost effectiveness of this design stems from the fact that few cases have both measures, and many cases have just the cheap measure. With 3 brief simulations involving structural equation models, the authors show that compared with the same-cost complete cases design, a 2-method measurement design yields lower standard errors and a higher effective sample size for testing important study parameters. With a large cost differential between cheap and expensive measures and small effect sizes, the benefits of the design can be enormous. Strategies for using these 2 designs are suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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