Secondary Hypotheses Research Articles

The NARC (Nonsteroidal Anti-inflammatory in Renal Colic) Trial. Single-dose intravenous ketorolac versus titrated intravenous meperidine in acute renal colic: a randomized clinical trial

Intravenous (IV) opioid titration is an accepted method of relieving acute renal colic. Studies have shown that nonsteroidal anti-inflammatory drugs (NSAIDs) are also effective in this setting. Our objective was to compare single-dose ketorolac and titrated meperidine, both administered intravenously, with respect to speed and degree of analgesia, adverse effects and functional status. Our primary hypothesis was that these agents provide equivalent analgesia within 60 minutes. Our secondary hypotheses were that ketorolac-treated patients would experience fewer adverse effects and would be better able to resume usual activity. This was a multicentre, double-blind randomized equivalence trial in a convenience sample of patients age 18-65 with moderate or severe renal colic, documented by intravenous pyelogram, ultrasound or stone passage. Meperidine-treated patients received 50 mg IV meperidine at 0 minutes, then 25-50 mg every 15 minutes as needed for ongoing pain. Ketorolac-treated patients received 30 mg IV ketorolac at 0 minutes and placebo injections every 15 minutes as needed. Pain levels and adverse effects were assessed every 15 minutes, and functional status was evaluated at 60 minutes. Our primary outcome was the proportion of patients with mild or no pain at 60 minutes. Overall, 49 of 77 meperidine-treated patients (64%; 95% confidence interval [CI], 53%-75%) and 47 of 65 ketorolac-treated patients (72%; 95% CI, 61%-83%) achieved successful pain relief at 60 minutes (p value for equivalence = 0.002). Ten percent of meperidine-treated patients and 44% of ketorolac-treated patients were able to resume usual activity at 60 minutes (p = 0.001). In the doses studied, single-dose IV ketorolac is as effective as titrated IV meperidine for the relief of acute renal colic and causes less functional impairment.

Prediction of antidepressant effects of sleep deprivation by metabolic rates in the ventral anterior cingulate and medial prefrontal cortex.

Sleep deprivation has been shown to have an antidepressant benefit in a subgroup of depressed patients. Functional imaging studies by the authors and others have suggested that patients with elevated metabolic rates in the anterior cingulate gyrus at baseline are more likely to respond to either sleep deprivation or antidepressant medications than patients with normal metabolic rates. The authors extend their earlier work in a larger group of patients and explore additional brain areas with statistical probability mapping. Thirty-six patients with unipolar depression and 26 normal volunteers were studied with positron emission tomography before and after sleep deprivation. Response to sleep deprivation was defined as a 40% or larger decrease in total scores on the Hamilton Depression Rating Scale. One-third of the depressed patients had a significant response to sleep deprivation. Responders had higher relative metabolic rates in the medial prefrontal cortex, ventral anterior cingulate, and posterior subcallosal gyrus at baseline than depressed patients who did not respond to sleep deprivation and normal volunteers. Lower Hamilton depression scores correlated significantly with lower metabolic rates in the left medial prefrontal cortex. After sleep deprivation, significant decreases in metabolic rates occurred in the medial prefrontal cortex and frontal pole in the patients who responded positively to sleep deprivation. High pretreatment metabolic rates and decreases in metabolic rates after treatment in the medial prefrontal cortex may characterize a subgroup of depressed patients who improve following sleep deprivation and, perhaps, other antidepressant treatments.

Party Fragmentation and Presidential Elections in Post-Communist Democracies

Despite its controversial status as a stable governmental form, many of today's societies attempting to make the transition to democracy have or will, for a variety of reasons, choose presidentialism. Meanwhile, the evidence suggests that the combination of presidentialism and multipartism is especially dangerous for democratic stability (Mainwaring 1994). The question this essay addresses, though, is whether presidential elections themselves serve to encourage a fragmented party system, at least in the initial stages of democratization. In transitional political systems presidential elections encourage party fragmentation, but in a way different from that of highly proportional purely parliamentary mechanisms. Specifically, parties proliferate to support the presidential aspirations of political elites. Multivariate regression analysis on cross-sectional aggregate electoral data, supported by extensive outliers diagnostics and assessments of the role of country-specific effects is applied. A nested model is used to discriminate among the secondary hypotheses. Controls include: parliamentary election rules (district magnitude, threshold for representation, adjustment districts, ballot structure), relative timing of presidential and parliamentary elections, and basic societal cleavage structure. Using as our data source the recent elections in East and Central Europe and the European part of the former Soviet Union, we show that presidential elections consistently significantly increase party fragmentation. At the same time, the data are consistent with the hypothesis that presidentialism does encourage the overall consolidation in party systems through voters' abandonment of some parties, akin to Duverger's 'psychological effect'.

Properties of profile parallelism tests in repeated measures designs

Properties of several test statistics for profile parallelism in repeated measures designs are evaluated by simulation. The procedures were derived to test secondary hypotheses in the presence of significant time by treatment interactions. Statistical techniques commonly available in computer packages are found to be inferior to the recommended test statistics.

Does a Prenatal Diagnosis of Congenital Heart Disease Alter Short-Term Outcome?

Congenital heart disease (CHD) is the most common fatal congenital anomaly in the first year after birth. Fetal echocardiography has become accepted as a method of diagnosing CHD in utero, but the benefits of prenatal diagnosis have not been evaluated. We performed a cohort analysis of neonates with CHD in the absence of other life-threatening conditions. One group (I) consisted of neonates who had been diagnosed as fetuses to have CHD and who were delivered at Yale-New Haven Hospital. The other group (II) consisted of neonates who were not diagnosed to have CHD until after birth, and were either delivered at, or transferred to, the same hospital. Costs of initial hospitalization, length of hospitalization, and survival to discharge home with the parents were primary outcome measures. Our primary hypothesis was that all outcome measures would be improved by prenatal diagnosis. We also examined secondary hypotheses that these same measures would be improved among selected subgroups, including those requiring univentricular management, those amenable to biventricular repair, those with ductal dependent lesions, and those requiring any surgery during the primary admission. From January 1, 1991 to June 30, 1996 we identified 45 antenatal cases and 54 postnatal cases of CHD that met the study entry criteria. The median length (+/- SE) of initial hospitalization was 16 +/- 3.8 days in group I, and 11 +/- 3.8 days in group II (p < 0.08). The median cost of initial hospitalization was $57,678 +/- 12,340 vs. $53,604 +/- 7249 (not significant). Eighty percent of group I survived to hospital discharge compared with 67% of group II (p = 0.14). There was no difference in survival among those requiring univentricular management (64 vs. 44%), but costs and length of hospitalization were greater in group I, regardless of whether or not surgery was performed postnatally. Surgery was undertaken more often among the prenatal diagnosis group with univentricular hearts (86 vs. 56%, p < 0.05). Among those fetuses amenable to biventricular repair, survival was better (96 vs. 76%, p < 0.05) and the cost of hospitalization was lower ($30,277 +/- 16,869 vs. $64,616 +/- 9441, p = 0.06) in the prenatal diagnosis group. Prenatal diagnosis of CHD does not result in the expected savings in cost, length of hospitalization or survival in the overall group of patients. The prenatal diagnosis group showed a skew towards single ventricle physiology. Within that group a high rate of pregnancy termination results in a group of parents who are likely to choose postnatal surgery despite high short- and long-term mortality risks.

Social influence techniques during marital conflict

AbstractThe use of social influence techniques was examined in two studies of marital conflict. In each study, couples discussed two issues in counterbalanced order: one in which the husband wanted change and one in which the wife wanted change. Interactions were coded for the use of influence techniques. Evidence from both studies supported a social role explanation, such that roles based on who wanted change predicted the use of influence, whereas gender did not. Secondary hypotheses based on attribution theory and schema theory were also supported. When discussing areas in which they wanted change in partners, spouses made more partner attributions, were more likely to suggest change, and were more likely to explain their partners’behavior than when discussing areas in which their partners wanted change. However, they were more likely to ask questions to clarify the problem when discussing a change their partners wanted in them than when discussing a change they wanted. The importance of considering social structural variables such as social roles in examining conflict interactions is discussed.

Does a prenatal diagnosis of congenital heart disease alter short-term outcome?

Congenital heart disease (CHD) is the most common fatal congenital anomaly in the first year after birth. Fetal echocardiography has become accepted as a method of diagnosing CHD in utero, but the benefits of prenatal diagnosis have not been evaluated. We performed a cohort analysis of neonates with CHD in the absence of other life-threatening conditions. One group (I) consisted of neonates who had been diagnosed as fetuses to have CHD and who were delivered at Yale-New Haven Hospital. The other group (II) consisted of neonates who were not diagnosed to have CHD until after birth, and were either delivered at, or transferred to, the same hospital. Costs of initial hospitalization, length of hospitalization, and survival to discharge home with the parents were primary outcome measures. Our primary hypothesis was that all outcome measures would be improved by prenatal diagnosis. We also examined secondary hypotheses that these same measures would be improved among selected subgroups, including those requiring univentricular management, those amenable to biventricular repair, those with ductal dependent lesions, and those requiring any surgery during the primary admission. From January 1, 1991 to June 30, 1996 we identified 45 antenatal cases and 54 postnatal cases of CHD that met the study entry criteria. The median length (+/- SE) of initial hospitalization was 16 +/- 3.8 days in group I, and 11 +/- 3.8 days in group II (p < 0.08). The median cost of initial hospitalization was $57,678 +/- 12,340 vs. $53,604 +/- 7249 (not significant). Eighty percent of group I survived to hospital discharge compared with 67% of group II (p = 0.14). There was no difference in survival among those requiring univentricular management (64 vs. 44%), but costs and length of hospitalization were greater in group I, regardless of whether or not surgery was performed postnatally. Surgery was undertaken more often among the prenatal diagnosis group with univentricular hearts (86 vs. 56%, p < 0.05). Among those fetuses amenable to biventricular repair, survival was better (96 vs. 76%, p < 0.05) and the cost of hospitalization was lower ($30,277 +/- 16,869 vs. $64,616 +/- 9441, p = 0.06) in the prenatal diagnosis group. Prenatal diagnosis of CHD does not result in the expected savings in cost, length of hospitalization or survival in the overall group of patients. The prenatal diagnosis group showed a skew towards single ventricle physiology. Within that group a high rate of pregnancy termination results in a group of parents who are likely to choose postnatal surgery despite high short- and long-term mortality risks.

Glucose and cholesterol elevations during thiazide therapy: Intention-to-treat versus actual on-therapy experience

This nonrandomized, parallel-group, prospective clinical series in consecutive patients was conducted to determine if the method of analysis of biochemical data collected in long-term treatment trials can explain the controversy regarding the effects of thiazides on plasma glucose or cholesterol. Fasting serum glucose, potassium, and cholesterol levels were determined before therapy, and yearly thereafter (4.0 +/- 0.1 years) in 634 consecutive patients treated for more than 1 year with antihypertensive monotherapy. When the data were analyzed by the intention-to-treat paradigm (ignoring changes in therapy), glucose and cholesterol levels in the thiazide group were significantly higher (compared to baseline or to the other therapy group) only at year 1. When the data were analyzed by actual on-therapy experience (censoring patients when therapy is altered)--a more traditional way to examine side effects--these differences were significant for all 5 years studied. Even if as few as 8% of patients who changed therapies were included in an intention-to-treat analysis, these differences became nonsignificant. These comparisons not only indicate why a dichotomy might exist between clinical practice (analyzed by actual on-therapy experience) and randomized trials (analyzed by intention-to-treat methods), regarding biochemical changes in glucose and cholesterol during thiazide therapy, but also that, for secondary hypotheses, analyzing data by both methods of assignment is important.

Local times on rays for a class of planar Lévy processes

LetX, Y be independent Levy processes on the real line. AssumeX andY admit Lebesgue measure as a reference measure, thatP0(Xt>0)=c for allt>0 (or the weaker conditionP0(Xt>0)=c ast→∞) and thatYt has a local time at points. We investigate the distribution of the local timeLt of (X, Y) on the positivex-axis. It turns out that, under the first hypothesis (which is in particular satisfied by planar Brownian motion), ifT is an independent exponential time, then the ratio ofLT tolT, the local time on the entirex axis, is (generalized) arc-sine and independent oflT, andLT has a Gamma distribution. We obtain then expressions for the distribution ofLt. In the case of Brownian motion, the formula involves parabolic cylinder functions. Under the weaker condition mentioned above, together with mild secondary hypotheses, we obtain an expression for the asymptotic distribution ofLt for larget.

A test of the maximum-power stimulus theory for strength.

The main purpose was to test the hypothesis that the true force and power in weightlifting were related significantly to the strengthening stimulus. Secondary hypotheses were (a) slower, heavier weight training for strength would increase strength, not maximum power, (b) faster, lighter weight training for maximum power would increase maximum power, not strength and (c) there would be no significant difference between force = mass (F = m) and true force = mass multiplied by acceleration (F = ma) for arm weightlifting. Using an optical encoder, digital recorder and a data-logging computer on an arm weightlifting machine, F = m and F = ma were significantly different between 25% and 94%, contrary to published reports, but not at 100% of strength. A second-order polynomial equation predicted force, F = ma, as a multiple of the weight lifted, from the velocity of the lift with R2 = 0.997. A group was trained for strength and a matched group was trained for maximum power. The strength group gained significantly in maximum power and the power group gained significantly in strength and maximum power. Both groups gained significantly in velocity, but not force, at maximum power. The correlations between strength and maximum power were high (r = 0.95-0.98, P < 0.02), consistent (before and after training) and valid (gain in standard error of estimate of 6 N or 2% of strength). The evidence suggested that maximum power was the strength stimulus. The maximum-power stimulus theory may unify and simplify theories of response and adaptation of structure and function induced by muscle.

Work-Related Self-Concept and Family Relations in Unemployed Married Men

It was hypothesized that unemployed men ( n = 50) would have significantly lower mean scores on work-related self-concept and family relations than employed men ( n = 50). Secondary hypotheses looked at the effect of the period of unemployment, method of job loss, and education on work-related self-concept. No significant differences were found between scores on work-related self-concept and family relations of the employed and the unemployed groups. The unemployed men with less education tended to have higher work-related self-concept scores than those with more education.

Systolic Hypertension of the Elderly Program (SHEP). Part 10: Analysis.

The SHEP is a randomized, placebo-controlled trial that will follow standard clinical trial principles in analyzing data relating to its proposed hypotheses. The protocol has stated a priori the main objective as well as the secondary subgroup hypotheses. Sample size calculations for SHEP have accounted for dropins to and drop-outs from active therapy as well as for the risk of nonstroke death. The sample size achieved (4,736 participants) should be adequate to address the proposed questions. Monitoring procedures have been described and established. A data and safety monitoring board that uses these procedures is closely following the data from the trial. The board will periodically examine the data to determine whether termination of the study is warranted.

Designing and Executing Randomized Clinical Trials Involving Elderly Persons

Although randomized clinical trials are the most scientifically rigorous design for evaluating a clinical intervention, the methodology involved is intricate, particularly when elderly subjects are involved. Special attention must be paid to framing precise primary and secondary study hypotheses, adjusting for the potential confounding effects of comorbidity and disability, and analyzing multiple outcomes. When the sample or study cohort is chosen, there will be an inevitable trade-off between internal and external validity. Because elderly study cohorts are more prognostically heterogeneous, consideration should be given to enrolling an "at-risk" cohort and possibly to stratified randomization.

Social skills deficits as a primary learning disability.

Advances in the definition of social skills deficits in children and youth with learning disabilities are presented and critiqued. The proposed modified definition of learning disability by the Interagency Committee on Learning Disabilities, which includes social skills deficits as a specific learning disability, is presented and discussed. This definition is analyzed from primary, secondary, and social learning theory causative hypotheses. Development of an adequate assessment technology is viewed as critical to the identification and classification of social skills deficits in children and youth with learning disabilities.

Comparisons of parameter and hypothesis definitions in a general linear model

In the context of the general linear model E(Y)=Xβ possibly subject to restrictions Rβ=r two secondary parameters may be well defined by Θi=GiE(Y)-Θoi=Ci β-Θoi,i=1,2, and corresponding nonconstant hypotheses, Hi:Θi=0. The following possible relations are defined: Θ1: is dependent upon /equivalent to/identical to Θ2:H1is a subhypothesis of/is identical to H2. Necessary and sufficient conditions, involving straightforward matrix computations, are presented for each relation. Comparisons of secondary parameters and hypotheses are illustrated with an incomplete, unbalanced 3 × 4 factorial design from Searle in which, using a constrained version of Searle's model, parameters and hypotheses in the incomplete, unbalanced design are shown to be indentical to parameters one would define if complete balanced data were available. Techniques for computing simplified definitions are illustrated.

Ego Identity and Desperate Love

The relationships between ego-identity consolidation, a romantic attitude toward love, and a desperate style of fusional love relations were examined using several questionnaire measures: Tan, Kendis, Fine, and Porac's (1977) Ego Identity Scale, Sperling's (1985) Desperate Love Scale, and Knox and Sporakowski's (1968) Attitude Toward Love Scale. Results based on an initial undergraduate sample of 84 men and 87 women, and a follow-up sample of 116 men, supported the primary hypothesis of a negative correlation between ego-identity consolidation and desperate love, as well as the secondary hypotheses.

College students' living arrangements and attitudes toward family roles: Demographic and value correlates

Using data from the college population, Pearson correlations and regression were used to examine three hypotheses. The major hypothesis was that “conformity-oriented” values are associated with college students' traditional living arrangements and family-related attitudes, while “self-directed” values are associated with nontraditional attitudes and behavior. Two other hypotheses focused on interrelationships among demographic variables, values, family-related attitudes, and living arrangements. General support was found for the major value-orientation hypothesis and mixed support for the secondary hypotheses. Comparing these findings with those of several other studies, we propose that there may be a subset of human values associated with general tendencies toward confomity and resistance to change on the one hand, and experimentation and receptivity to change on the other. A typology of such value orientations is put forward for future research in areas of sex roles, social change, sociopolitical conflict, and attitude and/or behavior change.

Differences Between Teaching Adults and Pre-Adults: Some Propositions and Findings

Do teachers teach adults differently from pre-adults and, if so, what are these differences and what factors determine their magnitude? To examine these questions, data were collected from 173 public school and college teachers who taught both adults and pre-adults. Hypotheses related to overall magnitude of differences in teaching behavior were tested using multiple regression. As predicted, differences in teaching behavior were related to the relative age of the pre-adult comparison group (i.e., greater for school teachers), the extent to which adults were perceived to differ from pre-adults on learning-related characteristics, and the extent to which teachers subscribed to the belief that groups of students with different characteristics should be taught differently. These variables accounted for 41 percent of the variance in the measure of overall difference in teaching behavior. Secondary hypotheses concerning the direction of specific differences in teaching behaviors and perceptions of student characteristics were tested with the t statistic. The results suggest that adults are perceived as more motivated, pragmatic, self-directed, and task-oriented than pre-adults. When teaching adults, as opposed to pre-adults, teachers appear to emphasize responsive, learner-centered behaviors and de-emphasize controlling and structuring be haviors. It was concluded that teachers do in fact teach adults differently from children and adolescents and that these differences can be explained to a significant extent by the variables employed in this study.

Differences Between Teaching Adults and Pre-Adults: Some Propositions And Findings

Do teachers teach adults differently from pre-adults and, if so, what are these differences and what factors determine their magnitude? To examine these questions, data were collected from 173 public school and college teachers who taught both adults and pre-adults. Hypotheses related to overall magnitude of differences in teaching behavior were tested using multiple regression. As predicted, differences in teaching behavior were related to the relative age of the pre-adult comparison group (i.e., greater for school teachers), the extent to which adults were perceived to differ from pre-adults on learning-related characteristics, and the extent to which teachers subscribed to the belief that groups of students with different characteristics should be taught differently. These variables accounted for 41 percent of the variance in the measure of overall difference in teaching behavior. Secondary hypotheses concerning the direction of specific differences in teaching behaviors and perceptions of student char...

Organizational Differentiation in Urban Communities: A Study in Organizational Ecology

Ecological theory suggests that growth in the density of a population of organizations should give rise, through the mechanism of competition, to functional differentiation and within functions, size differentiation. Such theory also predicts that size differentiation will increase as a consequence of functional differentiation. Tests of these hypotheses based on measurements for 206 SMSAs support these propositions with the exception that no direct effect of organizational density on size differentiation is observed. Secondary hypotheses about the influences of community age, urbanization, and economic function are also advanced and empirically evaluated. This study is conceived as an exploration in the ecology of organizations and confronts issues identified as important by other recent writers on these topics. The concept of an aggregate or population of organizations has caught the interest of sociologists pursuing various problems. Thinking of the urban community in such terms has led a number of writers to formulate propositions linking structural properties of the local organizational field to patterns of community integration and collective action (Aiken and Alford; Coleman; Turk). These efforts treat such properties as independent variables, however; hence are less helpful in explaining the composition of urban places in terms of them. One approach having this explanatory potential, as two recent papers suggest, is ecology. Hannan and Freeman and Aldrich and Pfeffer treat populations of organizations as an approach to the broad problem of organization-environment relations; and conclude that ecological models are best suited to a population-level analysis. Curiously, neither article gives more than passing attention to communities as systems supporting organizational populations, although human ecological theory addressing these topics has developed mainly in the course of a treatment of community structure (Hawley, a, Ch. 7). The present investigation, however, uses the urban community as the unit of analysis and *This paper has profited from critical readings by Michael Hannan, Barbara Laslett, and Kingsley Davis. Errors which remain are entirely my responsibility.