Showing papers by "University of Nebraska Omaha published in 2006"

Optimal movement variability: a new theoretical perspective for neurologic physical therapy.

Abstract: Variability is a natural and important feature of human movement. Using existing theoretical frameworks as a foundation, we propose a new model to explain movement variability as it relates to motor learning and health. We contend that mature motor skills and healthy states are associated with an optimal amount of movement variability. This variability also has form and is characterized by a chaotic structure. Less than optimal movement variability characterizes biological systems that are overly rigid and unchanging, whereas greater than optimal variability characterizes systems that are noisy and unstable. Both situations characterize systems that are less adaptable to perturbations, such as those associated with abnormal motor development or unhealthy states. From our perspective, the goal of neurologic physical therapy should be to foster the development of this optimal amount of movement variability by incorporating a rich repertoire of movement strategies. The development of such a repertoire can be enhanced by incorporating a multitude of experiences within the therapeutic milieu. Promoting complex variation in human movement allows either motor development or the recovery of function after injury not to be hard coded, but determined instead by the active engagement of the individual within their environment. Measurement tools derived from nonlinear dynamics that characterize the complexity of movement variability provide useful means of testing these propositions. To illustrate, we present 2 clinical case studies, one pediatric and one adult, where we applied our theoretical framework to measuring change in postural control.

Watchful waiting vs repair of inguinal hernia in minimally symptomatic men: A randomized clinical trial

Abstract: ContextMany men with inguinal hernia have minimal symptoms. Whether deferring surgical repair is a safe and acceptable option has not been assessed.ObjectiveTo compare pain and the physical component score (PCS) of the Short Form-36 Version 2 survey at 2 years in men with minimally symptomatic inguinal hernias treated with watchful waiting or surgical repair.Design, Setting, and ParticipantsRandomized trial conducted January 1, 1999, through December 31, 2004, at 5 North American centers and enrolling 720 men (364 watchful waiting, 356 surgical repair) followed up for 2 to 4.5 years.InterventionsWatchful-waiting patients were followed up at 6 months and annually and watched for hernia symptoms; repair patients received standard open tension-free repair and were followed up at 3 and 6 months and annually.Main Outcome MeasuresPain and discomfort interfering with usual activities at 2 years and change in PCS from baseline to 2 years. Secondary outcomes were complications, patient-reported pain, functional status, activity levels, and satisfaction with care.ResultsPrimary intention-to-treat outcomes were similar at 2 years for watchful waiting vs surgical repair: pain limiting activities (5.1% vs 2.2%, respectively; P = .52); PCS (improvement over baseline, 0.29 points vs 0.13 points; P = .79). Twenty-three percent of patients assigned to watchful waiting crossed over to receive surgical repair (increase in hernia-related pain was the most common reason offered); 17% assigned to receive repair crossed over to watchful waiting. Self-reported pain in watchful-waiting patients crossing over improved after repair. Occurrence of postoperative hernia-related complications was similar in patients who received repair as assigned and in watchful-waiting patients who crossed over. One watchful-waiting patient (0.3%) experienced acute hernia incarceration without strangulation within 2 years; a second had acute incarceration with bowel obstruction at 4 years, with a frequency of 1.8/1000 patient-years inclusive of patients followed up for as long as 4.5 years.ConclusionsWatchful waiting is an acceptable option for men with minimally symptomatic inguinal hernias. Delaying surgical repair until symptoms increase is safe because acute hernia incarcerations occur rarely.Clinical Trials RegistrationClinicalTrials.gov Identifier: NCT00263250

Rank-related maternal effects of androgens on behaviour in wild spotted hyaenas.

Abstract: Within any hierarchical society, an individual's social rank can have profound effects on its health and reproductive success, and rank-related variation in these traits is often mediated by variation in endocrine function. Maternal effects mediated by prenatal hormone exposure are potentially important for non-genetic inheritance of phenotypic traits related to social rank, and thus for shaping individual variation in behaviour and social structure. Here we show that androgen concentrations in wild female spotted hyaenas (Crocuta crocuta) are higher during late gestation in dominant females than in subordinate females. Furthermore, both male and female cubs born to mothers with high concentrations of androgens in late pregnancy exhibit higher rates of aggression and mounting behaviour than cubs born to mothers with lower androgen concentrations. Both behaviours are strongly affected in other mammals by organizational effects of androgens, and both have important effects on fitness in hyaenas. Therefore, our results suggest that rank-related maternal effects of prenatal androgen exposure can adaptively influence offspring phenotype in mammals, as has previously been shown to occur in birds. They also suggest an organizational mechanism for the development of female dominance and aggressiveness in spotted hyaenas, traits that may offset the costs of extreme virilization.

Current concepts in the diagnosis and management of metabolic complications of HIV infection and its therapy

Abstract: Changes in fat distribution, dyslipidemia, disordered glucose metabolism, and lactic acidosis have emerged as significant challenges to the treatment of human immunodeficiency virus (HIV) infection. Over the past decade, numerous investigations have been conducted to better define these conditions, identify risk factors associated with their development, and test potential therapeutic interventions. The lack of standardized diagnostic criteria, as well as disparate study populations and research methods, have led to conflicting data regarding the diagnosis and treatment of metabolic and body shape disorders associated with HIV infection. On the basis of a review of the medical literature published and/or data presented before April 2006, we have prepared a guide to assist the clinician in the detection and management of these complications.

Structural Breaks and Predictive Regression Models of Aggregate U.S. Stock Returns

Abstract: In this article we examine the structural stability of predictive regression models of U.S. quarterly aggregate real stock returns over the postwar era. We consider predictive regressions models of S&P 500 and CRSP equal-weighted real stock returns based on eight financial variables that display predictive ability in the extant literature. We test for structural stability using the popular Andrews SupF statistic and the Bai subsample procedure in conjunction with the Hansen heteroskedastic fixed-regressor bootstrap. We also test for structural stability using the recently developed methodologies of Elliott and Muller, and Bai and Perron. We find strong evidence of structural breaks in five of eight bivariate predictive regression models of S&P 500 returns and some evidence of structural breaks in the three other models. There is less evidence of structural instability in bivariate predictive regression models of CRSP equal-weighted returns, with four of eight models displaying some evidence of structural breaks. We also obtain evidence of structural instability in a multivariate predictive regression model of S&P 500 returns. When we estimate the predictive regression models over the different regimes defined by structural breaks, we find that the predictive ability of financial variables can vary markedly over time. Copyright 2006, Oxford University Press.

ThinkLets: a collaboration engineering pattern language

Abstract: Under the right circumstances, teams that use professional facilitators and Group Support Systems (GSS) experience significant gains in productivity and quality of work life. However, because of the expense, facilitators are not available to many teams that could benefit from their interventions. The emerging field of Collaboration Engineering aims to formulate an approach for designing high-value recurring collaboration processes that capture the best practices of master facilitators and packaging the processes in a fashion that can be transferred to practitioners to execute for themselves without the ongoing intervention of professional facilitators. Towards that end, Collaboration Engineering researchers have developed thinkLets, an Alexandrian design pattern language. A thinkLet is a named, packaged facilitation technique, captured as a pattern that collaboration engineers can incorporate into process designs. These patterns can be instantiated at design time in such a way that a practitioner can use them to recreate a predictable pattern of collaboration. This paper articulates the details of thinkLet design patterns and explains the utility that facilitators, collaboration engineers, researchers and practitioners are deriving from thinkLets in the field. It examines the parallels and differences among the goals and structures of the thinkLets pattern language, Alexander's architectural patterns and software design patterns.

Field Experiences with eXtreme Programming: Developing an Emergency Response System

Abstract: eXtreme Programming (XP) is a well-known agile software development method. While a number of reports have been published on explaining the XP methodology and the perceived benefits when using XP for system development in recent years, less is known about the actual operationalization of the XP principles. This paper presents an action research study reporting on the experiences of implementing the XP methodology in a development project for a Web-based, distributed information system. The goal of this research was to increase the understanding of how to effectively operationalize XP techniques so that the system being developed catered to today's fast-paced technological environment by allowing the developers to respond quickly to innovative and changing requirements. Overall, the research indicates that most of the XP principles could be effectively implemented; however, three of the principles required modification (i.e., testing, pair programming, customer collocation). Several benefits resulted from the usage of XP. The rapid prototyping enabled information technology developers and users to clarify system requirements, communicate openly, quickly build rapport, and create an interface that was easy to use and learn. Further, the research found that where the technology was new or foreign to the development team and the user, the XP process was flexible enough to support several iterations of technology and produce prototypes in a timely manner. Pair programming appeared to work effectively and offer value; however, it is not always practically feasible.

Organizational Transformation through Business Models: A Framework for Business Model Design

Abstract: Organizations are increasingly inter-connected as they source talent, goods and services from other organizations located in disparate parts of the world. They seek new ways of creating value for themselves, customers and partners. They operate outside and across traditional industry boundaries and definitions. These innovations have lead to a focus on business models as a fundamental statement of direction and identity. This paper highlights what is known about the business model concept and where and why it differs from more established concepts of business strategy. It illustrates how the application of business models has transformed organizations. The contribution of this paper is the guidance that it provides for business model design and the insight it provides into business models and their effects on organizations. Following an analysis of how business models can transform organizations, this paper concludes with practical recommendations for business model design.

A Novel Approach to Measure Variability in the Anterior Cruciate Ligament Deficient Knee During Walking: The Use of the Approximate Entropy in Orthopaedics

Abstract: Objective. The evaluation of variability of biological rhythmic activities through measures such as Approximate Entropy (ApEn) has provided important information regarding pathology in disciplines such as cardiology and neurology. This research lead to the “loss of complexity hypothesis” where decreased variability is associated with loss of healthy flexibility rendering the system more rigid and unable to adapt to stresses. ApEn as a measure of variability and complexity, correlates well with pathology while, in some cases, it is predictive of subsequent clinical changes. The study of human gait could benefit from the application of ApEn since it is also a rhythmical oscillation. Our aim was to assess the variability of the ACL deficient knee, since ACL rupture is a common musculoskeletal injury and is accompanied by altered gait patterns and future pathology in the joint. We hypothesized that the ACL deficient knee will exhibit more regular and less variable walking patterns than the contralateral intact knee. Methods. Ten subjects with unilateral deficiency walked on a treadmill at their self-selected speed, 20% faster, and 20% slower, while kinematics were collected (50 Hz) from 80 consecutive strides for each condition. The ApEn of the resulted knee joint flexion-extension time series was calculated. Results. Significantly smaller ApEn values were found in the ACL deficient knee when compared with the contralateral intact (F = 5.57, p = 0.022), for all speeds. ApEn values significantly increased (F = 5.79, p = 0.005) with increases in walking speed. Conclusions. The altered properties of the ACL deficient knee, which exhibits more regular and less variable patterns than the contralateral intact knee, may decrease the adaptability of the system rendering it less able to adjust to perturbations. This could explain the increased future pathology found in the deficient knee. ApEn can be an important tool in assessing pathology and therapeutic interventions in orthopaedics.

Shotgun proteomic analysis of human-induced sputum.

Abstract: Induced sputum is a readily accessible biological fluid whose composition may alter as a consequence of disease. To date, however, the proteins that routinely populate this biofluid are largely unknown, in part due to the technical difficulties in processing such mucin-rich samples. To provide a catalogue of sputum proteins, we have surveyed the proteome of human-induced sputum (sputome). A combination of 2-D gel analysis and GeLC-MS/MS allowed a total of 191 human proteins to be confidently assigned. In addition to the expected components, several hitherto unreported proteins were found to be present, including three members of the annexin family, kallikreins 1 and 11, and peroxiredoxins 1, 2 and 5. Other sets of proteins identified included four proteins previously annotated as hypothetical or conserved hypothetical. Taken together, these data represent the first extensive survey of the proteome of induced sputum and provide a platform for future identification of biomarkers of lung disease.

Voluntary Environmental Investment and Responsive Regulation

Abstract: Instances of corporate voluntary environmental investments have been rising in recent years. Motivations for such activities include corporate image building, regulatory preemption, and production cost savings. While some of these investments arise from industry attempts to set environmental standards where none currently exist, many investments seem to be aimed at reducing the costs of complying with existing regulations. Using a simple game-theoretic model, we investigate firm motivations for, and welfare consequences of, these types of voluntary investments by focusing on the role regulatory enforcement might play. We find that such investments unambiguously increase when an enforcement regulator acts as a Stackelberg follower (a regulatory structure we refer to as responsive regulation) in setting its monitoring and enforcement strategy. These additional investments may be socially undesirable, necessitating a restructuring of non-compliance penalties.

Meeting satisfaction for technology-supported groups: An empirical validation of a goal-attainment model

Abstract: Research shows that people who feel dissatisfied with a technology-supported meeting may discontinue use of such technology, even if it provides demonstrable benefits. It is therefore important to derive theoretical understandings of the satisfaction phenomenon. This article validates an instrument that measures the constructs of a goal-attainment model of meeting satisfaction. It then tests the model among 237 working professionals in 19 groups in the field. Results support the propositions that satisfaction with meeting process and satisfaction with meeting outcome are both a function of an individual's perceived net goal attainment with respect to the meeting. The results also support a proposed link between satisfaction with meeting outcome and satisfaction with meeting process. The authors discuss the implications of these findings for research and practice.

The unfolded protein response in lens epithelial cells from galactosemic rat lenses.

Abstract: PURPOSE. Diabetic complications are associated with hypoglycemia and hyperglycemia. The purpose of this study was to investigate the effect of both glucose deprivation and hyperglycemia on the induction of endoplasmic reticulum (ER) stress and the subsequent activation of the unfolded protein response (UPR) that results in apoptosis in in vitro cultured lens epithelial cells (LECs) and in vivo cataract formation in galactose-fed rats. METHODS. Lenses from rats fed a standard diet containing 50% galactose with or without an aldose reductase inhibitor (ARI) were investigated. Transformed human LECs were cultured in standard 10% FCS-DMEM containing various concentrations of sugar. UPR-specific proteins from both the rat lenses and lens cultures were quantified by protein blot analysis. Cell death was evaluated with TUNEL staining and ethidium homodimer-1 (EthD) dyes. Reactive oxygen species (ROS) were quantified with H2-DCF, and free glutathione (GSH) levels were measured with a commercial GSH quantification kit. RESULTS. Increased apoptosis of the LECs was observed in the lenses of rats fed the galactose diet for 5 to 9 days, and nuclear cataracts subsequently developed in these lenses after 13 to 15 days. Protein blot analysis of the LECs from these galactose-fed rats showed higher levels of the UPR-specific proteins Bip/ GRP78, ATF4, and CHOP. These LECs also demonstrated activation of the UPR-specific procaspase-12 and the increased presence of ROS, whereas GSH was reduced. Because these results indicate that the UPR is activated in LECs along with the production of ROS and apoptosis during cataract formation in the galactose-fed rats, subsequent studies were conducted to determine the role of nonenzymatic glycation, osmotic stress, and oxidative stress on these biochemical processes. In vitro cultures of human LECs showed that the UPR was induced by osmotic and oxidative stress, but not by glycation. In addition, the UPR and apoptosis in LECs was induced by glucose deprivation. The ARI blocked the induction of the UPR, cell death, and cataract formation. CONCLUSIONS. The UPR that is induced by abnormally high or low concentrations of sugar is linked to the production of ROS, increased apoptosis in LECs, and cataract formation. The inhibition of the UPR induction by ARI suggests that osmotic stress may be the primary inducer of the UPR. Modulation of the UPR pathways may offer novel methods for the development of therapeutic tools to delay cataracts. (Invest Ophthalmol Vis Sci. 2006;47:3951‐3959) DOI:10.1167/iovs.06-0193

Mugshot Exposure Effects: Retroactive Interference, Mugshot Commitment, Source Confusion, and Unconscious Transference

Abstract: More than 25 years of research has accumulated concerning the possible biasing effects of mugshot exposure to eyewitnesses Two separate metaanalyses were conducted on 32 independent tests of the hypothesis that prior mugshot exposure decreases witness accuracy at a subsequent lineup Mugshot exposure both signifi cantly decreased proportion correct and increased the false alarm rate, the effect being greater on false alarms A mugshot commitment effect, arising from the identifi cation of someone in a mugshot, was a substantial moderator of both these effects Simple retroactive interference, where the target person is not included among mugshots and no one in a mugshot is present in the subsequent lineup, did not signifi cantly impair target identifi cation A third metaanalysis was conducted on 19 independent tests of the hypothesis that failure of memory for facial source or context results in transference errors The effect size was more than twice as large for "transference" studies involving mugshot exposure in proximate temporal context with the target than for "bystander" studies with no subsequent mugshot exposure

Prognostic Value of Routine Preoperative Electrocardiography in Patients Undergoing Noncardiac Surgery

Abstract: Electrocardiography is commonly performed as part of preoperative cardiovascular risk assessment in patients undergoing noncardiac surgery. However, the prognostic value of such electrocardiography is still not clear. This study retrospectively studied 23,036 patients who underwent 28,457 surgical procedures at Erasmus Medical Center from 1991 to 2000. Patients were screened before surgery by type of surgery, cardiovascular risk factors (history of coronary heart disease, heart failure, diabetes mellitus, renal dysfunction, and stroke), and preoperative electrocardiography. Electrocardiographic (ECG) results showing atrial fibrillation, left or right bundle branch block, left ventricular hypertrophy, premature ventricular complexes, pacemaker rhythm, or Q-wave or ST-segment changes were classified as abnormal. Multivariate logistic regression was applied to evaluate the relation between ECG abnormalities and cardiovascular death. In-hospital cardiovascular death was observed in 199 of 28,457 patients (0.7%). Patients with abnormal ECG findings had a greater incidence of cardiovascular death than those with normal ECG results (1.8% vs 0.3%; adjusted odds ratio 4.5, 95% confidence interval 3.3 to 6.0). Adding ECG data to clinical risk factors and the type of surgery resulted in an improved C index for the prediction of cardiovascular death (0.79 vs 0.72). However, in patients who underwent low-risk or low- to intermediate-risk surgery, the absolute difference in the incidence of cardiovascular death between those with and without ECG abnormalities was only 0.5%. In conclusion, preoperative electrocardiography provides prognostic information in addition to clinical characteristics and the type of surgery. However, the usefulness of its routine use in lower risk surgery is questionable.

UNDERSTANDING MUSIC IN MOVEMENTS: The White Power Music Scene

Abstract: Relying on the analysis of ethnographic and documentary data, this article explains how U.S. White Power Movement (WPM) activists use music to produce collective occasions and experiences that we c...

Association of plasma N-terminal pro-B-type natriuretic peptide with postoperative cardiac events in patients undergoing surgery for abdominal aortic aneurysm or leg bypass.

Abstract: Postoperative cardiac events are related to myocardial ischemia and reduced left ventricular function. The utility of N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) for preoperative cardiac risk evaluation has not been evaluated. The objective of this study was to assess whether plasma NT-pro-BNP predicts postoperative cardiac events in patients who undergo major vascular surgery in addition to clinical and dobutamine stress echocardiographic data. One hundred seventy consecutive patients scheduled for major noncardiac vascular surgery were prospectively evaluated by dobutamine stress echocardiographic and NT-pro-BNP measurements. Multivariable logistic regression analysis was performed to evaluate the predictors of cardiac death and nonfatal myocardial infarction during a follow-up of 30-days. Receiver-operating characteristic analysis was performed to determine the optimal cut-off value of NT-pro-BNP to predict outcome. Patients' mean age was 59 +/- 13 years, and 71% were men. The median NT-pro-BNP level was 110 pg/ml (interquartile range 42 to 389). Cardiac events occurred in 2 of 144 patients (1.4%) with NT-pro-BNP or=533 pg/ml (unadjusted odds ratio 52, 95% confidence interval 11 to 256, p <0.0001). After adjustment for cardiac risk factors and dobutamine stress echocardiographic results, NT-pro-BNP remained significantly associated with cardiac events (adjusted odds ratio 17, 95% confidence interval 3 to 106, p = 0.002). In conclusion, in patients scheduled for major vascular surgery, elevated plasma NT-pro-BNP levels are independently associated with an increased risk for postoperative cardiac events. Further studies in a larger number of patients are required to confirm these findings.

Epidermal growth factor receptor expression regulates proliferation in the postnatal rat retina.

Abstract: Epidermal growth factor (EGF) is known to promote proliferation of both retinal progenitors and Muller glia in vitro, but several questions remain concerning an in vivo role for this factor. In this study, we investigated whether the EGF receptor (EGFR) is necessary for the maintenance of normal levels of progenitor and Muller glial proliferation in vivo. Here, we show that (1) mice with homozygous deletion of the Egfr gene have reduced proliferation in late stages of retinal histogenesis, (2) EGF is mitogenic for Muller glia in vivo during the first two postnatal weeks in the rodent retina, (3) the effectiveness of EGF as a Muller glial mitogen declines in parallel with the decline in EGFR expression as the retina matures, and (4) following damage to the retina from continuous light exposure, EGFR expression is up-regulated in Muller glia to levels close to those in the neonatal retina, resulting in a renewed mitotic response to EGF. Together with previous results from other studies, these data indicate that the downregulation of a growth factor receptor is one mechanism by which glial cells maintain mitotic quiescence in the mature nervous system.

Calibrating M Dwarf Metallicities Using Molecular Indices

Abstract: We report progress in the calibration of a method to determine cool dwarf star metallicities using molecular band strength indices. The molecular band index to metallicity relation can be calibrated using chemical abundances calculated from atomic-line equivalent width measurements in high-resolution spectra. Building on previous work, we have measured Fe and Ti abundances in 32 additional M and K dwarf stars to extend the range of temperature and metallicity covered. A test of our analysis method using warm star-cool star binaries shows we can calculate reliable abundances for stars warmer than 3500 K. We have used abundance measurements for warmer binary or cluster companions to estimate abundances in six additional cool dwarfs. Adding stars measured in our previous work and others from the literature provides 76 stars with Fe abundance and CaH2 and TiO5 index measurements. The CaH2 molecular index is directly correlated with temperature. TiO5 depends on temperature and metallicity. Metallicity can be estimated to within ±0.3 dex within the bounds of our calibration, which extends from roughly [{Fe}/H}] = +0.05 to –1.0, with a limited extension to –1.5.

CaCu3Ti4O12: Low-Temperature Synthesis by Pyrolysis of an Organic Solution

Abstract: The giant-dielectric-constant material CaCu3Ti4O12 (CCTO) has been synthesized by pyrolyzing an organic solution containing stoichiometric amounts of the metal cations, which is done at lower temperature and shorter reaction time than the conventional solid-state reaction. A stable solution was prepared by dissolving calcium nitrate, copper(II) nitrate, and titanium(IV) isopropoxide in 2-methoxyethanol. This solution was pyrolyzed and heat-treated to achieve single-phase CCTO. The phases, microstructures, and dielectric properties of intermediate and final samples were characterized by X-ray diffraction, scanning electron microscopy, and dielectric spectroscopy.

Community-Based Learning: Engaging Students for Success and Citizenship.

Abstract: Document Type Report Publication Date 2006 Abstract In recent years, national tragedies—both man-made and natural—have forced Americans to see how much we rely on strong neighborhoods, communities, and democratic institutions. We’ve seen how lack of attention to their well being affects us all. These events lay bare the moral imperative that underlies the mission of public education —to develop active, engaged citizens who are able to participate in and contribute fully to a democratic society. Recommended Citation Melaville, Atelia; Berg, Amy C.; and Blank, Martin J., "Community-Based Learning: Engaging Students for Success and Citizenship" (2006). Partnerships/Community. 40. https://digitalcommons.unomaha.edu/slcepartnerships/40  Download