Multiple contrasts and ordered Bonferroni procedures.

Describes procedures, based on the Bonferroni inequality, for avoiding increases in Type I errors that typically occur when an increasing number of contrasts is to be computed. The 3 types of Bonferroni tests differ in the degree to which the planned contrasts are specified beforehand and the relative importance attached to each one. This system of procedures is recommended for its flexibility, simplicity, and generality. When the power of the basic Bonferroni method is focused (by ordering the contrasts or other tests of significance by their importance), the disadvantage of conservatism can be overcome. Calculations are appended. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Type I and Type II Bias.

Errors in research do occur. Their prevalence should be viewed with alarm rather than passive acceptance as an essential concomitant of humans conducting research. The author looks at the discussion of errors in an article by Leroy Wolins (Amer. Psychologist, 1962, 17, 657-658) and an article by Emanuel Berger (Amer. Psychologist, 1962, 17, 657). The first article suggests that we may be quite unaware of the large proportion of the iceberg (erroneous research results) which is never perceived or reanalyzed. The second article pleads for experimental evaluation of research results. It would seem as though these two articles are both positively and negatively related. On the one hand, subjective evaluation and interpretation of research results may possibly expose inadvertent errors in computations (or in design, sampling, etc.). Thus, results which do not readily blend with an already established nomological network might call for statistical recomputations. On the other hand, subjective evaluation can become quite blinding when one identifies with or strongly favors certain results. In such cases, errors in computation would never be suspected, much less discovered. The author discusses experimental errors further, taking a look at Type I and Type II bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bootstrap Type I error rates for the correlation coefficient: An examination of alternate procedures.

This study examines three bootstrap procedures for estimating confidence intervals for the correlation coefficient. Results indicate that all three procedures produce slight inflation of the Type I error rate but that the inflation varies by method. Accordingly, choice of bootstrap procedure is an important consideration when testing hypotheses about correlations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlates of hypoglycemic fear in Type I and Type II diabetes mellitus.

Surveyed 232 outpatients with Type I and Type II diabetes, all requiring insulin. For the Type I and Type II groups, higher scores on the Worry subscale of the Hypoglycemia Fear Survey (HFS-W) were associated with higher levels of trait anxiety and fear. Higher scores on the Behavior subscale were associated with higher levels of fear. Among Type I Ss only, HFS-W scores were also positively associated with past hypoglycemic experience and with difficulty in differentiating anxiety and hypoglycemic symptoms. These latter relations remained significant even after the variance resulting from trait anxiety and fear was removed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

线路的线损率与工程设计中电压损失的关系

根据线路的线损率和电压损失的定义和计算公式,推导和分析了两者之间的关系,提出在工程设计阶段通过计算线路电压损失估算预期的线损率,并对企业常用的供电线路电压损失的控制值提出建议.     

Balancing connectedness and self-protection goals in close relationships: A levels-of-processing perspective on risk regulation.

A model of risk regulation is proposed to explain how low and high self-esteem people balance the tension between self-protection and connectedness goals in romantic relationships. This model assumes that interpersonal risk automatically activates connectedness and self-protection goals. The activation of these competing goals then triggers an executive control system that resolves this goal conflict. One correlational study and 8 experiments manipulating risk, goal strength, and executive strength and then measuring implicit and explicit goal activation and execution strongly supported the model. For people high in self-esteem, risk triggers a control system that directs them toward the situations of dependence within their relationship that can fulfill connectedness goals. For people low in self-esteem, however, the activation of connectedness goals triggers a control system that prioritizes self-protection goals and directs them away from situations where they need to trust or depend on their partner. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

高频功率NiZn铁氧体的高温功耗

采用传统氧化物法制备了具有成分分子式为Ni_0.5-xZn_0.5Co_xFe₂O₄(x=0,0.01,0.02,0.03)的高频功率NiZn铁氧体,并主要研究了其磁性能在-40~200℃宽温范围内随温度的变化关系.同时,还研究了Co³⁺的添加量对样品的高温功耗的影响.结果表明,适量地添加Co³⁺有助于铁氧体晶粒的均匀细化,高频功率NiZn铁氧体的起始磁导率和功率损耗的温度特性也得到了改善,功耗谷底温度随Co³⁺含量的增加逐步向低温方向移动.在-40~200℃宽温范围内,成分分子式为Ni_0.49Zn_0.5Co_0.01Fe₂O₄的样品不但具有极低的高频宽温功耗,而且具有良好的温度稳定性,其磁导率比温度系数为3×10^-6℃^-1,同时其在高温(100~200℃)下的功耗变化范围仅为130~140kW·m^-3,最低仅为130kW·m^-3(1MHz,10mT).     

Type I, Type II, and other types of errors in pattern analysis.

C. J. Krauskopf (1991) is to be commended for calling attention to the fact that pattern analysis is subject not only to Type I errors but also Type II errors, which were not even mentioned by A. B. Silverstein (1982). There are, however, a number of points on which the authors still differ. Most notably, Krauskopf's recommendation not only fails to solve the multiple-comparisons problem, it exacerbates that problem. Other possibilities are considered, including the possibility that the assumption on which pattern analysis is based, clinical meaningfulness, is itself an error. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Appropriate critical percentages for the Schmidt and Hunter meta-analysis procedure: Comparative evaluation of Type I error rate and power.

Recent investigations have shown that the Schmidt and Hunter 75% meta-analysis procedure (S&H–75%) does not have adequate control of the Type I error rate. This lack of control has caused two problems: First, the S&H–75% displays an erratic relationship between the likelihood to detect moderators and the number of studies included in the meta-analysis. Second, it has precluded meaningful power comparisons of the S&H–75% procedure with alternate procedures. In the present study we first determine appropriate critical percentages for the Schmidt and Hunter procedure that maintain a fixed Type I error rate. Then we compare this procedure, using the appropriate percentages, with an alternative statistic, U. When the correct percentages are used, the Schmidt and Hunter procedure shows equivalent power to the U statistic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

降低供电系统线损提高电能利用率

本文通过对线损的概念、产生原因、如何计算进行阐述,从技术降损和管理线损两个方面提出了降低线损的措施,使线损率长期保持在4%以下,提高了电能利用率。     

Comparison of power rates for combined probability procedures: A simulation study.

Compared the power of 6 techniques (adding logs, adding p's, mean p, adding z's, mean z, and adding t's) for combining the significance levels from independent tests of a common conceptual hypothesis using simulation procedures. Results indicate that for large numbers of studies to be combined, all procedures provided comparable power. The techniques varied in their ease of computation, however, making some procedures more preferrable under certain conditions. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multifactorial index of cardiac risk in noncardiac surgical procedures

To determine which preoperative factors might affect the development of cardiac complications after major noncardiac operations, we prospectively studied 1001 patients over 40 years of age. By multivariate discriminant analysis, we identified nine independent significant correlates of life-threatening and fatal cardiac complications: preoperative third heart sound or jugular venous distention; myocardial infarction in the preceding six months; more than five premature ventricular contractions per minute documented at any time before operation; rhythm other than sinus or presence of premature atrial contractions on preoperative electrocardiogram; age over 70 years; intraperitoneal, intrathoracic or aortic operation; emergency operation; important valvular aortic stenosis; and poor general medical condition. Patients could be separated into four classes of significantly different risk. Ten of the 19 postoperative cardiac fatalities occurred in the 18 patients at highest risk. If validated by prospective application, the multifactorial index may allow preoperative estimation of cardiac risk independent of direct surgical risk.     

The ordered assembly of the phiX174-type primosome. I. Isolation and identification of intermediate protein-DNA complexes

The phiX-type primosome was discovered during the resolution and reconstitution in vitro of the complementary strand DNA replication step of the phiX174 viral life cycle. This multienzyme bidirectional helicase-primase complex can provide the DNA unwinding and Okazaki fragment-priming functions at the replication fork and has been implicated in cellular DNA replication, repair, and recombination. We have used gel mobility shift assays and enhanced chemiluminescence Western analysis to isolate and identify the pathway of primosome assembly at a primosome assembly site (PAS) on a 300-nucleotide-long single-stranded DNA fragment. The first three steps do not require ATP and are as follows: (i) PriA recognition and binding to the PAS, (ii) stabilization of the PriA-PAS complex by the addition of PriB, and (iii) formation of a PriA-PriB-DnaT-PAS complex. Subsequent formation of the preprimosome involves the ATP-dependent transfer of DnaB from a DnaB-DnaC complex to the PriA-PriB-DnaT-PAS complex. The final preprimosomal complex contains PriA, PriB, DnaT, and DnaB but not DnaC. A transient interaction between the preprimosome and DnaG generates the five-protein primosome. As described in an accompanying article (Ng, J. Y., and Marians, K. J. (1996) J. Biol. Chem. 271, 15649-15655), when assembled on intact phiX174 phage DNA, the primosome also contains PriC.     

Multivariate analysis and the problem of Type I error.

Discusses the recommendation by M. R. Leary and E. M. Altmaier (see record 1981-02539-001) that MANOVA should be used with several dependent variables in order to control for overall Type I error rate. This paper calls attention to limitations and dangers in routine application of MANOVA, describes some alternative procedures, and laments the necessarily pervasive character of the problem of statistical error. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychological stress and blood glucose regulation in Type I diabetic patients.

Investigated whether psychological stress (PS) predicted blood glucose levels (BGLs), independent of self-management, in 15 Type I diabetic patients. Ss self-monitored daily mean BGLs, PS, diet, exercise, and insulin injections for 8 wks. Considerable individual variability in findings was evident, with PS predicting BGLs in a statistically significant manner in 7 Ss. PS had a significant effect on BGLs independent of the effects of diet, exercise, and insulin administration for the 7 Ss. Discussion focuses on the problems of measuring the key self-management behaviors influencing BGLs and on the possibility that a subgroup of diabetic patients may be BGL stress responders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On seeking moderator variables in the meta-analysis of correlational data: A Monte Carlo investigation of statistical power and resistance to Type I error.

A series of Monte Carlo computer simulations was conducted to investigate (a) the likelihood that meta-analysis will detect true differences in effect sizes rather than attributing differences to methodological artifact and (b) the likelihood that meta-analysis will suggest the presence of moderator variables when in fact differences in effect sizes are due to methodological artifact. The simulations varied the magnitude of the true population differences between correlations, the number of studies included in the meta-analysis, and the average sample size. Simulations were run both correcting and not correcting for measurement error. The power of 3 indices—the Schmidt-Hunter ratio of expected to observed variance, the Callender-Osburn procedure, and a chi-square test—to detect true differences was investigated. Results show that small true differences were not detected regardless of sample size and the number of studies and that moderate true differences were not detected with small numbers of studies or small sample sizes. Hence, there is a need for caution in attributing observed variation across studies to artifact. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rules and procedures.

Outlines 7 rules and procedures of the Committee on Scientific and Professional Ethics and Conduct. These include (1) responsibility and functions of committee, (2) scope and nature of authority, (3) correspondence and records, (4) receipt of complaints, (5) adjudication of complaints, (6) clearance of cases, and (7) communication on cases. (0 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)