Showing papers by "University of Southern California published in 1994"

Detecting Earnings Management

Abstract: This paper evaluates alternative models for detecting earnings management. The paper restricts itself to models that assume the construct being managed is discretionary accruals, since such models are commonly used in the extant accounting literature. Existing models range from simple models in which discretionary accruals are measured as total accruals, to more sophisticated models that separate total accruals into a discretionary and a non-discretionary component. Prior to this paper, there had been no systematic evidence bearing on the relative performance of these alternative models at detecting earnings management. This paper evaluates the relative performance of the competing models by comparing the specification and power of commonly used test statistics across the measures of discretionary accruals generated by each model. The specification of the test statistics is evaluated by examining the frequency with which they generate type I errors for a random sample of firm-years and for samples of firm-years with extreme financial performance. We focus on samples with extreme financial performance because the stimuli investigated in previous research are frequently correlated with financial performance. The first sample of firms are targeted by the Securities and Exchange Commission for allegedly overstating annual earnings and the second sample is created by artificially introducing earnings management into a random sample of firms.

Molecular computation of solutions to combinatorial problems

Abstract: The tools of molecular biology were used to solve an instance of the directed Hamiltonian path problem. A small graph was encoded in molecules of DNA, and the "operations" of the computation were performed with standard protocols and enzymes. This experiment demonstrates the feasibility of carrying out computations at the molecular level.

The lexical nature of syntactic ambiguity resolution

Abstract: Ambiguity resolution is a central problem in language comprehension. Lexical and syntactic ambiguities are standardly assumed to involve different types of knowledge representations and be resolved by different mechanisms. An alternative account is provided in which both types of ambiguity derive from aspects of lexical representation and are resolved by the same processing mechanisms. Reinterpreting syntactic ambiguity resolution as a form of lexical ambiguity resolution obviates the need for special parsing principles to account for syntactic interpretation preferences, reconciles a number of apparently conflicting results concerning the roles of lexical and contextual information in sentence processing, explains differences among ambiguities in terms of ease of resolution, and provides a more unified account of language comprehension than was previously available.

Media will never influence learning

Abstract: The purpose of this discussion is to explain and sharpen different points of view about the impact of media and attributes of media on learning, motivation and efficiency gains from instruction. This paper is an attempt to summarize my arguments about the research and theory in this area and to respond to Robert Kozma's criticism of my earlier discussion of these issues. I will first briefly summarize my arguments about media effects; next I will attempt to characterize the many reactions to the controversial claim that media do not influence learning or motivation. Finally, I will respond to the specific criticisms advanced by Robert Kozma this issue.

Kerberos: an authentication service for computer networks

Abstract: When using authentication based on cryptography, an attacker listening to the network gains no information that would enable it to falsely claim another's identity. Kerberos is the most commonly used example of this type of authentication technology. The authors concentrate on authentication for real-time, interactive services that are offered on computer networks. They use the term real-time loosely to mean that a client process is waiting for a response to a query or command so that it can display the results to the user, or otherwise continue performing its intended function. This class of services includes remote login, file system reads and writes, and information retrieval for applications like Mosaic. >

The Z/sub 4/-linearity of Kerdock, Preparata, Goethals, and related codes

Abstract: Certain notorious nonlinear binary codes contain more codewords than any known linear code. These include the codes constructed by Nordstrom-Robinson (1967), Kerdock (1972), Preparata (1968), Goethals (1974), and Delsarte-Goethals (1975). It is shown here that all these codes can be very simply constructed as binary images under the Gray map of linear codes over Z/sub 4/, the integers mod 4 (although this requires a slight modification of the Preparata and Goethals codes). The construction implies that all these binary codes are distance invariant. Duality in the Z/sub 4/ domain implies that the binary images have dual weight distributions. The Kerdock and "Preparata" codes are duals over Z/sub 4/-and the Nordstrom-Robinson code is self-dual-which explains why their weight distributions are dual to each other. The Kerdock and "Preparata" codes are Z/sub 4/-analogues of first-order Reed-Muller and extended Hamming codes, respectively. All these codes are extended cyclic codes over Z/sub 4/, which greatly simplifies encoding and decoding. An algebraic hard-decision decoding algorithm is given for the "Preparata" code and a Hadamard-transform soft-decision decoding algorithm for the I(Kerdock code. Binary first- and second-order Reed-Muller codes are also linear over Z/sub 4/, but extended Hamming codes of length n/spl ges/32 and the Golay code are not. Using Z/sub 4/-linearity, a new family of distance regular graphs are constructed on the cosets of the "Preparata" code. >

Fuzzy systems as universal approximators

Abstract: An additive fuzzy system can uniformly approximate any real continuous function on a compact domain to any degree of accuracy. An additive fuzzy system approximates the function by covering its graph with fuzzy patches in the input-output state space and averaging patches that overlap. The fuzzy system computes a conditional expectation E|Y|X| if we view the fuzzy sets as random sets. Each fuzzy rule defines a fuzzy patch and connects commonsense knowledge with state-space geometry. Neural or statistical clustering systems can approximate the unknown fuzzy patches from training data. These adaptive fuzzy systems approximate a function at two levels. At the local level the neural system approximates and tunes the fuzzy rules. At the global level the rules or patches approximate the function. >

Variance components testing in the longitudinal mixed effects model.

Abstract: This article discusses the asymptotic behavior of likelihood ratio tests for nonzero variance components in the longitudinal mixed effects linear model described by Laird and Ware (1982, Biometrics 38, 963-974). Our discussion of the large-sample behavior of likelihood ratio tests for nonzero variance components is based on the results for nonstandard testing situations by Self and Liang (1987, Journal of the American Statistical Association 82, 605-610).

Estrogen Deficiency and Risk of Alzheimer's Disease in Women

Abstract: The authors explored the possibility that estrogen loss associated with menopause may contribute to the development of Alzheimer's disease by using a case-control study nested within a prospective cohort study. The Leisure World Cohort includes 8,877 female residents of Leisure World Laguna Hills, a retirement community in southern California, who were first mailed a health survey in 1981. From the 2,529 female cohort members who died between 1981 and 1992, the authors identified 138 with Alzheimer's disease or other dementia diagnoses likely to represent Alzheimer's disease (senile dementia, dementia, or senility) mentioned on the death certificate. Four controls were individually matched by birth date (+/- 1 year) and death date (+1 year) to each case. The risk of Alzheimer's disease and related dementia was less in estrogen users relative to nonusers (odds ratio = 0.69, 95 percent confidence interval 0.46-1.03). The risk decreased significantly with increasing estrogen dose and with increasing duration of estrogen use. Risk was also associated with variables related to endogenous estrogen levels; it increased with increasing age at menarche and (although not statistically significant) decreased with increasing weight. This study suggests that the increased incidence of Alzheimer's disease in older women may be due to estrogen deficiency and that estrogen replacement therapy may be useful for preventing or delaying the onset of this dementia.

Accumulation of Nuclear p53 and Tumor Progression in Bladder Cancer

Abstract: Background We have previously demonstrated a strong association between nuclear accumulation of p53 protein, as determined by immunohistochemical analysis, and mutations in the p53 gene. The purpose of this study was to determine the relation between nuclear accumulation of p53 and tumor progression in transitional-cell carcinoma of the bladder. Methods Histologic specimens of transitional-cell carcinoma of the bladder (stages Pa, noninvasive disease, to P4, disease with direct extension into adjacent organs or structures) from 243 patients who were treated by radical cystectomy were examined for the immunohistochemical detection of p53 protein. Nuclear p53 reactivity was then analyzed in relation to time to recurrence and overall survival. Results The detection of nuclear p53 was significantly associated with an increased risk of recurrence of bladder cancer (P<0.001) and with decreased overall survival (P<0.001). In patients with cancer confined to the bladder, the rates of recurrence for stage P1, P2, ...

The Cognitive Abilities Screening Instrument (CASI): A practical test for cross-cultural epidemiological studies of dementia.

Abstract: The Cognitive Abilities Screening Instrument (CASI) has a score range of 0 to 100 and provides quantitative assessment on attention, concentration, orientation, short-term memory, long-term memory, language abilities, visual construction, list-generating fluency, abstraction, and judgment. Scores of the Mini-Mental State Examination, the Modified Mini-Mental State Test, and the Hasegawa Dementia Screening Scale can also be estimated from subsets of the CASI items. Pilot testing conducted in Japan and in the United States has demonstrated its cross-cultural applicability and its usefulness in screening for dementia, in monitoring disease progression, and in providing profiles of cognitive impairment. Typical administration time is 15 to 20 minutes. Record form, manual, videotape of test administration, and quizzes to qualify potential users on the administration and scoring of the CASI are available upon request.

A second Ewing's sarcoma translocation, t(21;22), fuses the EWS gene to another ETS–family transcription factor, ERG

Abstract: The t(11;22)(q24;q12), present in 85% of Ewing's sarcoma and related tumours, fuses the EWS gene from chromosome 22q12 and the ETS family member, FLI-1. This results in the expression of a chimaeric protein containing the amino-terminal portion of EWS fused to the ETS DNA-binding domain of FLI-1. We have identified a second Ewing's sarcoma translocation, t(21;22)(q22;q12), that fuses EWS to a different ETS family member, the ERG gene located on band 21q22. Identical EWS nucleotide sequences found in the EWS/FLI-1 fusion transcripts are fused to portions of ERG encoding an ETS DNA-binding domain resulting in expression of a hybrid EWS/ERG protein. These findings suggest that fusion of EWS to different members of the ETS family of transcription factor genes may result in the expression of similar disease phenotypes.

Bleeding peptic ulcer.

Abstract: Peptic ulcer is the most common cause of acute hemorrhage in the upper gastrointestinal tract, accounting for about 50 percent of cases1–14. There are approximately 150,000 hospitalizations per year in the United States for evaluation and treatment of bleeding ulcers (based on 1985 estimates and excluding federal hospitals)15. Although hospitalization and surgery for uncomplicated ulcers have decreased in the United States and Europe over the past 20 to 30 years, the number of hospital admissions for hemorrhage associated with ulcers has remained relatively unchanged15–17. It is noteworthy that the incidence of bleeding ulcers appears to . . .

Minimum Price Variations, Discrete Bid–Ask Spreads, and Quotation Sizes

Abstract: Exchange minimum price variation regulations create discrete bid-ask spreads. If the minimum quotable spread exceeds the spread that otherwise would be quoted, spreads will be wide and the number of shares offered at the bid and ask may be large. A cross-sectional discrete spread model is estimated by using intraday stock quotation spread frequencies. The results are used to project $1/16 spread usage frequencies given a $1/16 tick. Projected changes in quotation sizes and in trade volumes are obtained from regression models. For stocks priced under $10, the models predict spreads would decrease 38 percent, quotation sizes would decrease 16 percent, and daily volume would increase 34 percent. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.

Congruence between spokesperson and product type: A matchup hypothesis perspective

Abstract: This study tested the matchup hypothesis regarding choice of celebrity spokesperson by examining the fit or congruence between image type and the product advertised from an Identification and Internalization viewpoint (Kelman, 1961). Spokesperson type (celebrity versus noncelebrity) was varied, aong with congruence between spokesperson image and product (higher versus lower congruence) in a 2x2 factorial design. Results showed that increased congruence for the spokesperson/product combination resulted in the perception of higher believability and attractiveness of the spokesperson and a more favorable product attitude. The implications of these and other findings for advertising and marketing strategy are discussed. © 1994 John Wiley & Sons, Inc.

A follow-up study of urinary markers of aflatoxin exposure and liver cancer risk in Shanghai, People's Republic of China.

Abstract: A cohort of 18,244 mostly middle-aged (45-64 years) men residing in four small geographically defined areas of Shanghai was accrued between January 1986 and September 1989. In addition to an in-person interview regarding dietary and other past exposures, each subject donated a single void urine sample at recruitment so that the presence of aflatoxins in urine could be assessed. In addition, a 1-year survey of market foods in Shanghai was conducted to quantitatively estimate the extent of aflatoxin exposure in the study population. After close to 70,000 person-years of follow-up, 55 incident cases of hepatocellular carcinoma (HCC) had been identified. Levels of urinary aflatoxin B1 and the oxidative metabolites, including the major aflatoxin nucleic acid adduct, aflatoxin-N7-guanine, were determined for 50 of the 55 identified cases of HCC. Two hundred sixty-seven controls were chosen randomly from the cohort; they were matched to the 50 cases by age (within 1 year), time of specimen collection (within 1 month), and residence. After integrating the high-pressure liquid chromatography chromatograms to measure aflatoxin-N7-guanine, aflatoxin M1, aflatoxin P1, and aflatoxin B1, 49, 67, 53, and 71 of the urine samples had detectable levels of these compounds, respectively. The aflatoxin metabolite detected at the highest concentration was aflatoxin P1; the range was 0.59-16.0 ng/ml. The range of aflatoxin M1 in the urine was 0.17-5.2 ng/ml. The aflatoxin-N7-guanine adduct range was 0.3-1.81 ng/ml in the 49 positive samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Low-power digital systems based on adiabatic-switching principles

Abstract: Adiabatic switching is an approach to low-power digital circuits that differs fundamentally from other practical low-power techniques. When adiabatic switching is used, the signal energies stored on circuit capacitances may be recycled instead of dissipated as heat. We describe the fundamental adiabatic amplifier circuit and analyze its performance. The dissipation of the adiabatic amplifier is compared to that of conventional switching circuits, both for the case of a fixed voltage swing and the case when the voltage swing can be scaled to reduce power dissipation. We show how combinational and sequential adiabatic-switching logic circuits may be constructed and describe the timing restrictions required for adiabatic operation. Small chip-building experiments have been performed to validate the techniques and to analyse the associated circuit overhead. >

The age of paradox

Abstract: Preface Part 1--In the Dark Wood Confused by Paradox We Are Not Where We Hoped to Be The Paradoxes of Our Times Part 2--Finding the Balance Pathways through Paradox Working with the Paradoxes The Sigmoid Curve The Doughnut Principle The Chinese Contract Part 3--Practicing the Preaching Managing Paradox The Federal Idea Twin Citizenship Subsidiarity The Meaning of Business The Corporate Contract The Membership Business A State of Justice The Intelligence Investment The New Scorecard Part 4--The Search for Meaning Making Sense of Paradox The Three Senses A Sense of Continuity A Sense of Connection A Sense of Direction A Postscript Two Stories Acknowledgments Bibliography Index

Two molecular pathways to transitional cell carcinoma of the bladder.

Abstract: Noninvasive transitional cell carcinomas of the bladder can have two distinct morphologies suggesting they contain different genetic alterations. Papillary transitional cell carcinomas (T(a) tumors) are often multifocal and only occasionally progress, whereas flat tumors (carcinomas in situ, CIS), frequently progress to invasive disease. We examined 216 bladder tumors of various stages and histopathologies for two genetic alterations previously described to be of importance in bladder tumorigenesis. Loss of heterozygosity of chromosome 9 was observed in 24 of 70 (34%) T(a) tumors but was present in only 3 of 24 (12%) CIS and dysplasia lesions (P = 0.04). In contrast, only 1 of 36 (3%) T(a) tumors contained a p53 gene mutation compared to 15 of 23 (65%) CIS and dysplasias (P < 0.001), a frequency comparable to that observed in muscle invasive tumors (25 of 49; 51%). The presence of p53 mutations in CIS and dysplasia could explain their propensities to progress since these mutations are known to destabilize the genome. Analysis of several tumor pairs involving a CIS and an invasive cancer provided evidence that the chromosome 9 alteration may in some cases be involved in the progression of CIS to more invasive tumors, in addition to its role in the initiation of T(a) tumors. However, the CIS and secondary tumor were found to contain different genetic alterations in some patients suggesting divergent progression pathways. Bladder carcinogenesis may therefore proceed through two distinct genetic alteration pathways responsible for generating superficial tumors with differing morphologies and pathologies.

The US economic and social costs of Alzheimer's disease revisited.

Abstract: OBJECTIVEs. An earlier paper estimated the per-case and national incidence costs of Alzheimer's disease for 1983. This paper updates the estimates of costs per case to 1991 and presents new national prevalence estimates of the economic and social costs of the disease. METHODS. All data for the cost estimates were taken from published sources or provided by other researchers. RESULTS. At midrange values of the estimated cost and epidemiological parameters, the discounted (at 4%) direct and total costs of Alzheimer's disease were $47,581 and $173,932 per case, respectively. The estimated 1991 national direct and total prevalence costs were $20.6 billion and $67.3 billion, respectively. Assuming conservatively that the prevalence of the disease remains constant, the estimated discounted present values of the direct and total costs of all current and future generations of Alzheimer's patients are $536 billion and $1.75 trillion, respectively. CONCLUSIONS. The $536 billion and $1.75 trillion figures are minimu...

Estrogen replacement therapy in older women. Comparisons between Alzheimer's disease cases and nondemented control subjects.

Abstract: Objectives: We hypothesized that oral estrogen replacement therapy would be less common among elderly women meeting criteria for Alzheimer's disease (AD) than among nondemented elderly women. For women with AD, we hypothesized that estrogen users would perform better on a cognitive task than would nonusers. Design: A case-control study of estrogen replacement therapy, in which hierarchical procedures were used to control for potentially confounding effects of age and education. When cognitive performances were compared between estrogen users and nonusers with AD, the duration of dementia symptoms was an additional control variable. Setting: Alzheimer's Disease Research Center at the University of Southern California, Los Angeles. Subjects: Subjects were a volunteer sample of consecutively enrolled elderly women, recruited primarily from the community, who met clinical criteria for probable AD (n=143) or met criteria for nondemented control status (n=92). Seventy case patients who have subsequently died met histopathologic criteria for AD; one other demented woman who did not meet the autopsy criteria for AD was excluded from all analyses. Main Outcome Measures: Current use of estrogen replacement at the time of enrollment as reported by control subjects or by the primary caregivers of AD case patients. Among cases, performances on a brief cognitive screening instrument were compared between estrogen users (n=10) and nonusers (n=128) for whom this information was available. Results: Alzheimer's disease case patients were significantly less likely than control subjects to use estrogen replacement (7% vs 18%), but groups did not differ with regard to the total number of prescription medications or to the most frequently prescribed class of drug (thyroid medication). Demented case patients using estrogen did not differ significantly from those not using estrogen in terms of age, education, or symptom duration, but their mean performance on a cognitive screening instrument was significantly better (Mini-Mental State examination scores of 14.9 vs 6.5). Conclusions: Findings are consistent with contentions that postmenopausal estrogen replacement therapy may be associated with a decreased risk of AD and that estrogen replacement may improve cognitive performance of women with this illness.

Sampling Theory for Neutral Alleles in a Varying Environment

Abstract: We develop a sampling theory for genes sampled from a population evolving with deterministically varying size. We use a coalescent approach to provide recursions for the probabilities of particular sample configurations, and describe a Monte Carlo method by which the solutions to such recursions can be approximated. We focus on infinite-alleles, infinite-sites and finite-sites models. This approach may be used to find maximum likelihood estimates of parameters of genetic interest, and to test hypotheses about the varying environment. The methods are illustrated with data from the mitochondrial control region sampled from a North American Indian tribe.

Organization of projections from the ventromedial nucleus of the hypothalamus: a Phaseolus vulgaris-leucoagglutinin study in the rat.

Abstract: The organization of projections from the four parts of the ventromedial nucleus (VMH) and a ventrolaterally adjacent region tentatively identified as the tuberal nucleus (TU) have been analyzed with small injections of the anterograde axonal tracer Phaseolus vulgaris-leucoagglutinin (PHA-L). Extrinsic and intranuclear projections of each part of the VMH display clear quantitative differences, whereas the overall patterns of outputs are qualitatively similar. Overall, the VMH establishes massive intrahypothalamic terminal fields in other parts of the medial zone, tending to avoid the periventricular and lateral zones. The ventrolateral VMH is more closely related to other parts of the hypothalamus that also express gonadal steroid hormone receptors, including the medial preoptic, tuberal, and ventral premammillary nuclei, whereas other parts of the VMH are more closely related to the anterior hypothalamic and dorsal premammillary nuclei. All parts of the VMH project to the zona incerta (including the A13 region) and parts of the midline thalamus, including the paraventricular and parataenial nuclei and nucleus reuniens. The densest inputs to the septum are to the bed nuclei of the stria terminalis, where the ventrolateral and central VMH innervate the anteroventral and anterodorsal areas and transverse and interfascicular nuclei, whereas the anterior and dorsomedial VMH innervate the latter two. The central, lateral, and medial amygdalar nuclei receive substantial inputs from various parts of the VMH. Other regions of the telencephalon, including the nucleus accumbens and the piriform-amygdaloid, infralimbic, prelimbic, anterior cingulate, agranular insular, piriform, perirhinal, entorhinal, and postpiriform transition areas, also receive sparse inputs. All parts of the VMH send a massive, topographically organized projection to the periaqueductal gray. Other brainstem terminal fields include the superior colliculus, peripeduncular area, locus coeruleus, Barrington's nucleus, parabrachial nucleus, nucleus of the solitary tract, and the mesencephalic, pontine, gigantocellular, paragigantocellular, and parvicellular reticular nuclei. The projections of the TU are similar to, and a subset of, those from the VMH and are thus not nearly as widespread as those from adjacent parts of the lateral hypothalamic area. Because of these similarities, the TU may eventually come to be viewed most appropriately as the lateral component of the VMH itself. The functional implications of the present findings are discussed in view of evidence that the VMH plays a role in the expression of ingestive, affective, and copulatory behaviors.

A Comparision of Spacing and Headway Control Laws for Automatically Controlled Vehicles1

Abstract: SUMMARY This paper investigates two different longitudinal control policies for automatically controlled vehicles. One is based on maintaining a constant spacing between the vehicles while the other is based upon maintaining a constant headway (or time) between successive vehicles. To avoid collisions in the platoon, controllers have to be designed to ensure string stability, i.e the spacing errors should not get amplified as they propagate upstream from vehicle to vehicle. A measure of string stability is introduced and a systematic method of designing constant spacing controllers which guarantee string stability is presented. The constant headway policy does not require inter-vehicle communication to assure string stablity. Also, since inter-vehicle communication is not required it can be used in systems with mixed automated-nonautomated vehicles, e.g for AICC (Autonomous Intelligent Cruise Control). It is shown in this paper that for all the autonomous headway control laws, the desired control torques ...

Sensitivity of HER-2/neu Antibodies in Archival Tissue Samples: Potential Source of Error in Immunohistochemical Studies of Oncogene Expression

Abstract: HER-2/ neu oncogene amplification and overexpression of breast cancer tissue has been correlated with poor prognosis in women with both node-positive and node-negative disease. However, several studies have not confirmed this association. Review of these studies reveals the presence of considerable methodological variability including differences in study size, follow-up time, techniques and reagents. The majority of papers with clinical follow-up information are immunohistochemical studies using archival, paraffin-embedded breast cancers, and a variety of HER-2/ neu antibodies have been used in these studies. Very little information, however, is available about the ability of the antibodies to detect overexpression following tissue processing for paraffin-embedding. Therefore, a series of antibodies, reported in the literature or commercially available, were evaluated to assess their sensitivity and specificity as immunohistochemical reagents. Paraffin-embedded samples of 187 breast cancers, previously characterized as frozen specimens for HER-2/ neu amplification by Southern blot and for overexpression by Northern blot, Western blot, and immunohistochemistry, were used. Two multitumor paraffin-embedded tissue blocks were prepared from the previously analyzed breast cancers as a panel of cases to test a series of previously studied and/or commercially available anti-HER-2/ neu antibodies. Immunohistochemical staining results obtained with 7 polyclonal and 21 monoclonal antibodies in sections from paraffin-embedded blocks of these breast cancers were compared. The ability of these antibodies to detect overexpression was extremely variable, providing an important explanation for the variable overexpression rate reported in the literature.

Genomic instability in repeated sequences is an early somatic event in colorectal tumorigenesis that persists after transformation.

Abstract: Genomic instability at simple repeated sequences (SRS) is a landmark for some sporadic and hereditary cancers of the colon. We have identified several human tumour cell lines with up to 1,000–fold increases in mutation rates for endogenous microsatellite sequences, relative to normal cells or tumour cells without the mutator phenotype and show that they are very early events in tumorigenesis. Our in vivo and in vitro results show that the genomic instability persists after transformation and that microsatellite mutations accumulate as consecutive somatic slippage events of a single or a few repeated units. This mechanism may account for the repeat expansions in triplet hereditary diseases and the same defect in replication fidelity in non–polyposis colon cancer could also contribute to the non–mendelian anticipation in these diseases.

Immediate and long-term impacts of child sexual abuse.

Abstract: Research conducted over the past decade indicates that a wide range of psychological and interpersonal problems are more prevalent among those who have been sexually abused than among individuals with no such experiences. Although a definitive causal relationship between such difficulties and sexual abuse cannot be established using current retrospective research methodologies, the aggregate of consistent findings in this literature has led many to conclude that childhood sexual abuse is a major risk factor for a variety of problems. This article summarizes what is currently known about these potential impacts of child sexual abuse. The various problems and symptoms described in the literature on child sexual abuse are reviewed in a series of broad categories including posttraumatic stress, cognitive distortions, emotional pain, avoidance, an impaired sense of self, and interpersonal difficulties. Research has demonstrated that the extent to which a given individual manifests abuse-related distress is a function of an undetermined number of abuse-specific variables, as well as individual and environmental factors that existed prior to, or occurred subsequent to, the incidents of sexual abuse.

The Effectiveness of Self-Managing Teams: A Quasi-Experiment

Abstract: This study used a quasi-experimental design to assess the effectiveness of self-managing teams in a telecommunications company. These teams performed customer service, technical support, administrative support, and managerial functions in a variety of locations. The balance of evidence indicates that self-managing teams were more effective than comparable traditionally-managed groups that performed the same type of work. The study illustrates the value of a collaborative research project in which researchers and clients jointly define the research questions, study design, and methods.