Showing papers by "McMaster University published in 2005"

Cognitive radio: brain-empowered wireless communications

Abstract: Cognitive radio is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment and uses the methodology of understanding-by-building to learn from the environment and adapt to statistical variations in the input stimuli, with two primary objectives in mind: /spl middot/ highly reliable communication whenever and wherever needed; /spl middot/ efficient utilization of the radio spectrum. Following the discussion of interference temperature as a new metric for the quantification and management of interference, the paper addresses three fundamental cognitive tasks. 1) Radio-scene analysis. 2) Channel-state estimation and predictive modeling. 3) Transmit-power control and dynamic spectrum management. This work also discusses the emergent behavior of cognitive radio.

Simulations of the formation, evolution and clustering of galaxies and quasars

Abstract: The cold dark matter model has become the leading theoretical picture for the formation of structure in the Universe. This model, together with the theory of cosmic inflation, makes a clear prediction for the initial conditions for structure formation and predicts that structures grow hierarchically through gravitational instability. Testing this model requires that the precise measurements delivered by galaxy surveys can be compared to robust and equally precise theoretical calculations. Here we present a simulation of the growth of dark matter structure using 2,1603 particles, following them from redshift z = 127 to the present in a cube-shaped region 2.230 billion lightyears on a side. In postprocessing, we also follow the formation and evolution of the galaxies and quasars. We show that baryon-induced features in the initial conditions of the Universe are reflected in distorted form in the low-redshift galaxy distribution, an effect that can be used to constrain the nature of dark energy with future generations of observational surveys of galaxies.

Effects of computerized clinical decision support systems on practitioner performance and patient outcomes: a systematic review.

Abstract: ContextDevelopers of health care software have attributed improvements in patient care to these applications. As with any health care intervention, such claims require confirmation in clinical trials.ObjectivesTo review controlled trials assessing the effects of computerized clinical decision support systems (CDSSs) and to identify study characteristics predicting benefit.Data SourcesWe updated our earlier reviews by searching the MEDLINE, EMBASE, Cochrane Library, Inspec, and ISI databases and consulting reference lists through September 2004. Authors of 64 primary studies confirmed data or provided additional information.Study SelectionWe included randomized and nonrandomized controlled trials that evaluated the effect of a CDSS compared with care provided without a CDSS on practitioner performance or patient outcomes.Data ExtractionTeams of 2 reviewers independently abstracted data on methods, setting, CDSS and patient characteristics, and outcomes.Data SynthesisOne hundred studies met our inclusion criteria. The number and methodologic quality of studies improved over time. The CDSS improved practitioner performance in 62 (64%) of the 97 studies assessing this outcome, including 4 (40%) of 10 diagnostic systems, 16 (76%) of 21 reminder systems, 23 (62%) of 37 disease management systems, and 19 (66%) of 29 drug-dosing or prescribing systems. Fifty-two trials assessed 1 or more patient outcomes, of which 7 trials (13%) reported improvements. Improved practitioner performance was associated with CDSSs that automatically prompted users compared with requiring users to activate the system (success in 73% of trials vs 47%; P = .02) and studies in which the authors also developed the CDSS software compared with studies in which the authors were not the developers (74% success vs 28%; respectively, P = .001).ConclusionsMany CDSSs improve practitioner performance. To date, the effects on patient outcomes remain understudied and, when studied, inconsistent.

Leader-Member Exchange as a Mediator of the Relationship Between Transformational Leadership and Followers' Performance and Organizational Citizenship Behavior

Abstract: We developed a model in which leader-member exchange mediated between perceived transformational leadership behaviors and followers' task performance and organizational citizenship behaviors. Our s...

Unconventional Integer Quantum Hall Effect in Graphene

Abstract: Monolayer graphite films, or graphene, have quasiparticle excitations that can be described by $(2+1)$-dimensional Dirac theory. We demonstrate that this produces an unconventional form of the quantized Hall conductivity ${\ensuremath{\sigma}}_{xy}=\ensuremath{-}(2{e}^{2}/h)(2n+1)$ with $n=0,1,\dots{}$, which notably distinguishes graphene from other materials where the integer quantum Hall effect was observed. This unconventional quantization is caused by the quantum anomaly of the $n=0$ Landau level and was discovered in recent experiments on ultrathin graphite films.

The Health and Well-Being of Caregivers of Children With Cerebral Palsy

Abstract: Objective. Most children enjoy healthy childhoods with little need for specialized health care services. However, some children experience difficulties in early childhood and require access to and utilization of considerable health care resources over time. Although impaired motor function is the hallmark of the cerebral palsy (CP) syndromes, many children with this development disorder also experience sensory, communicative, and intellectual impairments and may have complex limitations in self-care functions. Although caregiving is a normal part of being the parent of a young child, this role takes on an entirely different significance when a child experiences functional limitations and possible long-term dependence. One of the main challenges for parents is to manage their child9s chronic health problems effectively and juggle this role with the requirements of everyday living. Consequently, the task of caring for a child with complex disabilities at home might be somewhat daunting for caregivers. The provision of such care may prove detrimental to both the physical health and the psychological well-being of parents of children with chronic disabilities. It is not fully understood why some caregivers cope well and others do not. The approach of estimating the “independent” or “direct” effects of the care recipient9s disability on the caregiver9s health is of limited value because (1) single-factor changes are rare outside the context of constrained experimental situations; (2) assumptions of additive relationships and perfect measurements rarely hold; and (3) such approaches do not provide a complete perspective, because they fail to examine indirect pathways that occur between predictor variables and health outcomes. A more detailed analytical approach is needed to understand both direct and indirect effects simultaneously. The primary objective of the current study was to examine, within a single theory-based multidimensional model, the determinants of physical and psychological health of adult caregivers of children with CP. Methods. We developed a stress process model and applied structural equation modeling with data from a large cohort of caregivers of children with CP. This design allowed the examination of the direct and indirect relationships between a child9s health, behavior and functional status, caregiver characteristics, social supports, and family functioning and the outcomes of caregivers9 physical and psychological health. Families ( n = 468) of children with CP were recruited from 19 regional children9s rehabilitation centers that provide outpatient disability management and supports in Ontario, Canada. The current study drew on a population available to the investigators from a previous study, the Ontario Motor Growth study, which explored patterns of gross motor development in children with CP. Data on demographic variables and caregivers9 physical and psychological health were assessed using standardized, self-completed parent questionnaires as well as a face-to-face home interview. Structural equation modeling was used to test specific hypotheses outlined in our conceptual model. This analytic approach involved a 2-step process. In the first step, observed variables that were hypothesized to measure the underlying constructs were tested using confirmatory factor analysis; this step led to the so-called measurement model. The second step tested hypotheses about relationships among the variables in the structural model. All of the hypothesized paths in the conceptual model were tested and included in the structural model. However, only paths that were significant were shown in the final results. The direct, indirect, and total effects of theoretical constructs on physical and psychological health were calculated using the structural model. Results. The most important predictors of caregivers9 well-being were child behavior, caregiving demands, and family function. A higher level of behavior problems was associated with lower levels of both psychological (β = −.22) and physical health (β = −.18) of the caregivers, whereas fewer child behavior problems were associated with higher self-perception (β = −.37) and a greater ability to manage stress (β = −.18). Less caregiving demands were associated with better physical (β = .23) and psychological (β = .12) well-being of caregivers, respectively. Similarly, higher reported family functioning was associated with better psychological health (β = .33) and physical health (β = .33). Self-perception and stress management were significant direct predictors of caregivers9 psychological health but did not directly influence their physical well-being. Caregivers9 higher self-esteem and sense of mastery over the caregiving situation predicted better psychological health (β = .23). The use of more stress management strategies was also associated with better psychological health of caregivers (β = .11). Gross income (β = .08) and social support (β = .06) had indirect overall effects only on psychological health outcome, whereas self-perception (β = .22), stress management (β = .09), gross income (β = .07), and social support (β = .06) had indirect total effects only on physical health outcomes. Conclusions. The psychological and physical health of caregivers, who in this study were primarily mothers, was strongly influenced by child behavior and caregiving demands. Child behavior problems were an important predictor of caregiver psychological well-being, both directly and indirectly, through their effect on self-perception and family function. Caregiving demands contributed directly to both the psychological and the physical health of the caregivers. The practical day-to-day needs of the child created challenges for parents. The influence of social support provided by extended family, friends, and neighbors on health outcomes was secondary to that of the immediate family working closely together. Family function affected health directly and also mediated the effects of self-perception, social support, and stress management. In families of children with CP, strategies for optimizing caregiver physical and psychological health include supports for behavioral management and daily functional activities as well as stress management and self-efficacy techniques. These data support clinical pathways that require biopsychosocial frameworks that are family centered, not simply technical and short-term rehabilitation interventions that are focused primarily on the child. In terms of prevention, providing parents with cognitive and behavioral strategies to manage their child9s behaviors may have the potential to change caregiver health outcomes. This model also needs to be examined with caregivers of children with other disabilities.

A review and evaluation of intraurban air pollution exposure models

Abstract: The development of models to assess air pollution exposures within cities for assignment to subjects in health studies has been identified as a priority area for future research. This paper reviews models for assessing intraurban exposure under six classes, including: (i) proximity-based assessments, (ii) statistical interpolation, (iii) land use regression models, (iv) line dispersion models, (v) integrated emission-meteorological models, and (vi) hybrid models combining personal or household exposure monitoring with one of the preceding methods. We enrich this review of the modelling procedures and results with applied examples from Hamilton, Canada. In addition, we qualitatively evaluate the models based on key criteria important to health effects assessment research. Hybrid models appear well suited to overcoming the problem of achieving population representative samples while understanding the role of exposure variation at the individual level. Remote sensing and activity-space analysis will complement refinements in pre-existing methods, and with expected advances, the field of exposure assessment may help to reduce scientific uncertainties that now impede policy intervention aimed at protecting public health.

Receptor and viral determinants of SARS-coronavirus adaptation to human ACE2

Abstract: Human angiotensin-converting enzyme 2 (ACE2) is a functional receptor for SARS coronavirus (SARS-CoV) Here we identify the SARS-CoV spike (S)-protein-binding site on ACE2 We also compare S proteins of SARS-CoV isolated during the 2002-2003 SARS outbreak and during the much less severe 2003-2004 outbreak, and from palm civets, a possible source of SARS-CoV found in humans All three S proteins bound to and utilized palm-civet ACE2 efficiently, but the latter two S proteins utilized human ACE2 markedly less efficiently than did the S protein obtained during the earlier human outbreak The lower affinity of these S proteins could be complemented by altering specific residues within the S-protein-binding site of human ACE2 to those of civet ACE2, or by altering S-protein residues 479 and 487 to residues conserved during the 2002-2003 outbreak Collectively, these data describe molecular interactions important to the adaptation of SARS-CoV to human cells, and provide insight into the severity of the 2002-2003 SARS epidemic

Self-assessment in the health professions: a reformulation and research agenda.

Abstract: Many researchers and educators have identified self-assessment as a vital aspect of professional self-regulation.1,2,3 This rationale has been the expressed motivation for a large number of studies of self-assessment ability in medical education, health professional education, and professions educat

Research in clinical reasoning: past history and current trends.

Abstract: Background Research in clinical reasoning has been conducted for over 30 years. Throughout this time there have been a number of identifiable trends in methodology and theory. Purpose This paper identifies three broad research traditions, ordered chronologically, are: (a) attempts to understand reasoning as a general skill − the ‘clinical reasoning' process; (b) research based on probes of memory − reasoning related to the amount of knowledge and memory; and (c) research related to different kinds of mental representations − semantic qualifiers, scripts, schemas and exemplars. Results and Conclusions Several broad themes emerge from this review. First, there is little evidence that reasoning can be characterised in terms of general process variables. Secondly, it is evident that expertise is associated, not with a single basic representation but with multiple coordinated representations in memory, from causal mechanisms to prior examples. Different representations may be utilised in different circumstances, but little is known about the characteristics of a particular situation that led to a change in strategy. Implications It becomes evident that expertise lies in the availability of multiple representations of knowledge. Perhaps the most critical aspect of learning is not the acquisition of a particular strategy or skill, nor is it the availability of a particular kind of knowledge. Rather, the critical element may be deliberate practice with multiple examples which, on the hand, facilitates the availability of concepts and conceptual knowledge (i.e. transfer) and, on the other hand, adds to a storehouse of already solved problems.

Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans

Abstract: Parra et al. (Acta Physiol. Scand 169: 157–165, 2000) showed that 2 wk of daily sprint interval training (SIT) increased citrate synthase (CS) maximal activity but did not change “anaerobic” work c...

Childhood obesity, prevalence and prevention.

Abstract: Childhood obesity has reached epidemic levels in developed countries. Twenty five percent of children in the US are overweight and 11% are obese. Overweight and obesity in childhood are known to have significant impact on both physical and psychological health. The mechanism of obesity development is not fully understood and it is believed to be a disorder with multiple causes. Environmental factors, lifestyle preferences, and cultural environment play pivotal roles in the rising prevalence of obesity worldwide. In general, overweight and obesity are assumed to be the results of an increase in caloric and fat intake. On the other hand, there are supporting evidence that excessive sugar intake by soft drink, increased portion size, and steady decline in physical activity have been playing major roles in the rising rates of obesity all around the world. Consequently, both over-consumption of calories and reduced physical activity are involved in childhood obesity. Almost all researchers agree that prevention could be the key strategy for controlling the current epidemic of obesity. Prevention may include primary prevention of overweight or obesity, secondary prevention or prevention of weight regains following weight loss, and avoidance of more weight increase in obese persons unable to lose weight. Until now, most approaches have focused on changing the behaviour of individuals in diet and exercise. It seems, however, that these strategies have had little impact on the growing increase of the obesity epidemic. While about 50% of the adults are overweight and obese in many countries, it is difficult to reduce excessive weight once it becomes established. Children should therefore be considered the priority population for intervention strategies. Prevention may be achieved through a variety of interventions targeting built environment, physical activity, and diet. Some of these potential strategies for intervention in children can be implemented by targeting preschool institutions, schools or after-school care services as natural setting for influencing the diet and physical activity. All in all, there is an urgent need to initiate prevention and treatment of obesity in children.

What every teacher needs to know about clinical reasoning

Abstract: Context One of the core tasks assigned to clinical teachers is to enable students to sort through a cluster of features presented by a patient and accurately assign a diagnostic label, with the development of an appropriate treatment strategy being the end goal. Over the last 30 years there has been considerable debate within the health sciences education literature regarding the model that best describes how expert clinicians generate diagnostic decisions. Purpose The purpose of this essay is to provide a review of the research literature on clinical reasoning for frontline clinical teachers. The strengths and weaknesses of different approaches to clinical reasoning will be examined using one of the core divides between various models (that of analytic (i.e. conscious/controlled) versus non-analytic (i.e. unconscious/automatic) reasoning strategies) as an orienting framework. Discussion Recent work suggests that clinical teachers should stress the importance of both forms of reasoning, thereby enabling students to marshal reasoning processes in a flexible and context-specific manner. Specific implications are drawn from this overview for clinical teachers.

Prevalence of Vitamin D Inadequacy among Postmenopausal North American Women Receiving Osteoporosis Therapy

Abstract: Purpose: To evaluate serum 25-hydroxyvitamin D [25(OH)D] concentrations and factors related to vitamin D inadequacy in postmenopausal North American women receiving therapy to treat or prevent osteoporosis. Methods: Serum 25(OH)D and PTH were obtained in 1536 community-dwelling women between November 2003 and March 2004. Multivariate logistic regression was used to assess risk factors for suboptimal (<30 ng/ml) 25(OH)D. Results: Ninety-two percent of study subjects were Caucasian, with a mean age of 71 yr. Thirty-five percent resided at or above latitude 42° north, and 24% resided less than 35° north. Mean (sd) serum 25(OH)D was 30.4 (13.2) ng/ml: serum 25(OH)D was less than 20 ng/ml in 18%; less than 25 ng/ml in 36%; and less than 30 ng/ml in 52%. Prevalence of suboptimal 25(OH)D was significantly higher in subjects who took less than 400 vs. 400 IU/d or more vitamin D. There was a significant negative correlation between serum PTH concentrations and 25(OH)D. Risk factors related to vitamin D inadequacy ...

Randomized trials stopped early for benefit: a systematic review

Abstract: ContextRandomized clinical trials (RCTs) that stop earlier than planned because of apparent benefit often receive great attention and affect clinical practice. Their prevalence, the magnitude and plausibility of their treatment effects, and the extent to which they report information about how investigators decided to stop early are, however, unknown.ObjectiveTo evaluate the epidemiology and reporting quality of RCTs involving interventions stopped early for benefit.Data SourcesSystematic review up to November 2004 of MEDLINE, EMBASE, Current Contents, and full-text journal content databases to identify RCTs stopped early for benefit.Study SelectionRandomized clinical trials of any intervention reported as having stopped early because of results favoring the intervention. There were no exclusion criteria.Data ExtractionTwelve reviewers working independently and in duplicate abstracted data on content area and type of intervention tested, reporting of funding, type of end point driving study termination, treatment effect, length of follow-up, estimated sample size and total sample studied, role of a data and safety monitoring board in stopping the study, number of interim analyses planned and conducted, and existence and type of monitoring methods, statistical boundaries, and adjustment procedures for interim analyses and early stopping.Data SynthesisOf 143 RCTs stopped early for benefit, the majority (92) were published in 5 high-impact medical journals. Typically, these were industry-funded drug trials in cardiology, cancer, and human immunodeficiency virus/AIDS. The proportion of all RCTs published in high-impact journals that were stopped early for benefit increased from 0.5% in 1990-1994 to 1.2% in 2000-2004 (P<.001 for trend). On average, RCTs recruited 63% (SD, 25%) of the planned sample and stopped after a median of 13 (interquartile range [IQR], 3-25) months of follow-up, 1 interim analysis, and when a median of 66 (IQR, 23-195) patients had experienced the end point driving study termination (event). The median risk ratio among truncated RCTs was 0.53 (IQR, 0.28-0.66). One hundred thirty-five (94%) of the 143 RCTs did not report at least 1 of the following: the planned sample size (n = 28), the interim analysis after which the trial was stopped (n = 45), whether a stopping rule informed the decision (n = 48), or an adjusted analysis accounting for interim monitoring and truncation (n = 129). Trials with fewer events yielded greater treatment effects (odds ratio, 28; 95% confidence interval, 11-73).ConclusionsRCTs stopped early for benefit are becoming more common, often fail to adequately report relevant information about the decision to stop early, and show implausibly large treatment effects, particularly when the number of events is small. These findings suggest clinicians should view the results of such trials with skepticism.

Effect of glucose-insulin-potassium infusion on mortality in patients with acute ST-segment elevation myocardial infarction: The CREATE-ECLA randomized controlled trial

Abstract: Context Glucose-insulin-potassium (GIK) infusion is a widely applicable, low-cost therapy that has been postulated to improve mortality in patients with acute ST-segment elevation myocardial infarction (STEMI). Given the potential global importance of GIK infusion, a large, adequately powered randomized trial is required to determine the effect of GIK on mortality in patients with STEMI. Objective To determine the effect of high-dose GIK infusion on mortality in patients with STEMI. Design, setting, and participants Randomized controlled trial conducted in 470 centers worldwide among 20,201 patients with STEMI who presented within 12 hours of symptom onset. The mean age of patients was 58.6 years, and evidence-based therapies were commonly used. Intervention Patients were randomly assigned to receive GIK intravenous infusion for 24 hours plus usual care (n = 10,091) or to receive usual care alone (controls; n = 10,110). Main outcome measures Mortality, cardiac arrest, cardiogenic shock, and reinfarction at 30 days after randomization. Results At 30 days, 976 control patients (9.7%) and 1004 GIK infusion patients (10.0%) died (hazard ratio [HR], 1.03; 95% confidence interval [CI], 0.95-1.13; P = .45). There were no significant differences in the rates of cardiac arrest (1.5% [151/10 107] in control and 1.4% [139/10,088] in GIK infusion; HR, 0.93; 95% CI, 0.74-1.17; P = .51), cardiogenic shock (6.3% [640/10 107] vs 6.6% [667/10 088]; HR, 1.05; 95% CI, 0.94-1.17; P = .38), or reinfarction (2.4% [246/10,107] vs 2.3% [236/10,088]; HR, 0.98; 95% CI, 0.82-1.17; P = .81). The rates of heart failure at 7 days after randomization were also similar between the groups (16.9% [1711/10,107] vs 17.1% [1721/10,088]; HR, 1.01; 95% CI, 0.95-1.08; P = .72). The lack of benefit of GIK infusion on mortality was consistent in prespecified subgroups, including in those with and without diabetes, in those presenting with and without heart failure, in those presenting early and later after symptom onset, and in those receiving and not receiving reperfusion therapy (thrombolysis or primary percutaneous coronary intervention). Conclusion In this large, international randomized trial, high-dose GIK infusion had a neutral effect on mortality, cardiac arrest, and cardiogenic shock in patients with acute STEMI.

Systematic review of long-term weight loss studies in obese adults: clinical significance and applicability to clinical practice

Abstract: Systematic review of long-term weight loss studies in obese adults: clinical significance and applicability to clinical practice

Precursor form of brain-derived neurotrophic factor and mature brain-derived neurotrophic factor are decreased in the pre-clinical stages of Alzheimer's disease.

Abstract: Brain-derived neurotrophic factor (BDNF) is critical for the function and survival of neurons that degenerate in the late stage of Alzheimer's disease (AD). There are two forms of BDNF, the BDNF precursor (proBDNF) and mature BDNF, in human brain. Previous studies have shown that BDNF mRNA and protein, including proBDNF, are dramatically decreased in end-stage AD brain. To determine whether this BDNF decrease is an early or late event during the progression of cognitive decline, we used western blotting to measure the relative amounts of BDNF proteins in the parietal cortex of subjects clinically classified with no cognitive impairment (NCI), mild cognitive impairment (MCI) or mild to moderate AD. We found that the amount of proBDNF decreased 21 and 30% in MCI and AD groups, respectively, as compared with NCI, consistent with our previous results of a 40% decrease in end-stage AD. Mature BDNF was reduced 34 and 62% in MCI and AD groups, respectively. Thus, the decrease in mature BDNF and proBDNF precedes the decline in choline acetyltransferase activity which occurs later in AD. Both proBDNF and mature BDNF levels were positively correlated with cognitive measures such as the Global Cognitive Score and the Mini Mental State Examination score. These results demonstrate that the reduction of both forms of BDNF occurs early in the course of AD and correlates with loss of cognitive function, suggesting that proBDNF and BDNF play a role in synaptic loss and cellular dysfunction underlying cognitive impairment in AD.

Towards systematic reviews that inform health care management and policy-making.

Abstract: Objectives: To identify ways to improve the usefulness of systematic reviews for health care managers and policy-makers that could then be evaluated prospectively. Methods: We systematically reviewed studies of decision-making by health care managers and policy-makers, conducted interviews with a purposive sample of them in Canada and the United Kingdom (n ¼ 29), and reviewed the websites of research funders, producers/purveyors of research, and journals that include them among their target audiences (n ¼ 45). Results: Our systematic review identi¢ed that factors such as interactions between researchers and health care policy-makers and timing/timeliness appear to increase the prospects for research use among policymakers. Our interviews with health care managers and policy-makers suggest that they would bene¢t from having information that is relevant for decisions highlighted for them (e.g. contextual factors that aiect a review’s local applicability and information about the bene¢ts, harms/risks and costs of interventions) and having reviews presented in a way that allows for rapid scanning for relevance and then graded entry (such as one page of take-home messages, a three-page executive summary and a 25-page report). Managers and policy-makers have mixed views about the helpfulness of recommendations. Our analysis of websites found that contextual factors were rarely highlighted, recommendations were often provided and graded entry formats were rarely used. Conclusions: Researchers could help to ensure that the future £ow of systematic reviews will better inform health care management and policy-making by involving health care managers and policy-makers in their production and better highlighting information that is relevant for decisions. Research funders could help to ensure that the global stock of systematic reviews will better inform health care management and policymaking by supporting and evaluating local adaptation processes such as developing and making available online more user-friendly ‘front ends’ for potentially relevant systematic reviews.

Electrodynamics of high- T c superconductors

Abstract: Recent studies of the electromagnetic response of high-Tc superconductors using terahertz, infrared, and optical spectroscopies are reviewed. In combination these experimental techniques provide a comprehensive picture of the low-energy excitations and charge dynamics in this class of materials. These results are discussed with an emphasis on conceptual issues, including evolution of the electronic spectral weight in doped Mott-Hubbard insulators, the d-wave superconducting energy gap and the normal-state pseudogap, anisotropic superfluid response, electronic phase segregation, emergence of coherent electronic state as a function of both temperature and doping, the vortex state, and the energetics of the superconducting transition. Because the theoretical understanding of these issues is still evolving the review is focused on the analysis of the universal trends that are emerging out of a large body of work carried on by many research teams. Where possible data generated by infrared/optical techniques are compared with the data from other spectroscopic and transport methods.

Perioperative cardiac events in patients undergoing noncardiac surgery: a review of the magnitude of the problem, the pathophysiology of the events and methods to estimate and communicate risk

Abstract: This is the first of 2 articles evaluating cardiac events in patients undergoing noncardiac surgery. In this article, we review the magnitude of the problem, the pathophysiology of these events, approaches to risk assessment and communication of risk. The number of patients undergoing noncardiac surgery worldwide is growing, and annually 500,000 to 900,000 of these patients experience perioperative cardiac death, nonfatal myocardial infarction (MI) or nonfatal cardiac arrest. Although the evidence is limited, a substantial proportion of fatal perioperative MIs may not share the same pathophysiology as nonoperative MIs. A clearer understanding of the pathophysiology is needed to direct future research evaluating prophylactic, acute and long-term interventions. Researchers have developed tools to facilitate the estimation of perioperative cardiac risk. Studies suggest that the Lee index is the most accurate generic perioperative cardiac risk index. The limitations of the studies evaluating the ability of noninvasive cardiac tests to predict perioperative cardiac risk reveals considerable uncertainty as to the role of these popular tests. Similarly, there is uncertainty as to the predictive accuracy of the American College of Cardiology/American Heart Association algorithm for cardiac risk assessment. Patients are likely to benefit from improved estimation and communication of cardiac risk because the majority of noncardiac surgeries are elective and accurate risk estimation is important to allow informed patient and physician decision-making.

Feeling the Beat: Movement Influences Infant Rhythm Perception

Abstract: We hear the melody in music, but we feel the beat. We demonstrate that the perception of musical rhythm is a multisensory experience in infancy. In particular, movement of the body, by bouncing on every second versus every third beat of an ambiguous auditory rhythm pattern, influences whether that auditory rhythm pattern is encoded in duple form (a march) or in triple form (a waltz). Visual information is not necessary for the effect, indicating that it likely reflects a strong, early-developing interaction between auditory and vestibular information in the human nervous system.

Merkel cell carcinoma: changing incidence trends.

Abstract: Background The objective of this study was to define the incidence trends of Merkel cell carcinoma (MCC), a rare and aggressive cutaneous malignancy. Materials and Methods All cases of MCC of the skin between 1986 and 2001 were identified using the surveillance, epidemiology, and end results (SEER) program. Overall age-adjusted, gender-specific, age-specific, stage-specific, and regional incidence rates were calculated. All rates are per 100,000 and age-adjusted to the 2000 US standard population. Estimated annual percent change (EAPC) was calculated using a linear least squares model. Results A total of 1,124 cases of MCC were identified in the SEER registries. The rate of MCC increased from 0.15 cases per 100,000 in 1986 to 0.44 cases per 100,000 in 2001. The EAPC for the time period was 8.08%. This was statistically significant (95% CI: 6.29, 9.90, P-value < 0.05). Age-specific incidence (5-year age groups) were highest in the elderly, 4.28 per 100,000 in the 85+ age group. Conclusions MCC incidence rates have increased threefold over the 1986–2001 period. Rates are highest in the elderly population. Further etiologic studies and identification of high-risk populations are warranted. J. Surg. Oncol. 2005;89:1–4. © 2004 Wiley-Liss, Inc.