Showing papers by "Temple University published in 2004"

The importance of intrinsic disorder for protein phosphorylation

Abstract: Reversible protein phosphorylation provides a major regulatory mechanism in eukaryotic cells. Due to the high variability of amino acid residues flanking a relatively limited number of experimentally identified phosphorylation sites, reliable prediction of such sites still remains an important issue. Here we report the development of a new web-based tool for the prediction of protein phosphorylation sites, DISPHOS (DISorder-enhanced PHOSphorylation predictor, http://www.ist.temple. edu/DISPHOS). We observed that amino acid compositions, sequence complexity, hydrophobicity, charge and other sequence attributes of regions adjacent to phosphorylation sites are very similar to those of intrinsically disordered protein regions. Thus, DISPHOS uses position-specific amino acid frequencies and disorder information to improve the discrimination between phosphorylation and non-phosphorylation sites. Based on the estimates of phosphorylation rates in various protein categories, the outputs of DISPHOS are adjusted in order to reduce the total number of misclassified residues. When tested on an equal number of phosphorylated and non-phosphorylated residues, the accuracy of DISPHOS reaches 76% for serine, 81% for threonine and 83% for tyrosine. The significant enrichment in disorder-promoting residues surrounding phosphorylation sites together with the results obtained by applying DISPHOS to various protein functional classes and proteomes, provide strong support for the hypothesis that protein phosphorylation predominantly occurs within intrinsically disordered protein regions.

Risk Taking in Adolescence: What Changes, and Why?

Abstract: Extant studies of age differences in cognitive processes relevant to risk taking and decision making, such as risk perception and risk appraisal, indicate few significant age differences in factors that might explain why adolescents engage in more risk taking than adults The present analysis suggests that the greater propensity of adolescents to take risks is not due to age differences in risk perception or appraisal, but to age differences in psychosocial factors that influence self-regulation It is argued that adolescence is a period of heightened vulnerability to risk taking because of a disjunction between novelty and sensation seeking (both of which increase dramatically at puberty) and the development of self-regulatory competence (which does not fully mature until early adulthood) This disjunction is biologically driven, normative, and unlikely to be remedied through educational interventions designed to change adolescents' perception, appraisal, or understanding of risk Interventions should begin from the premise that adolescents are inherently more likely than adults to take risks, and should focus on reducing the harm associated with risk-taking behavior

Democracy online: civility, politeness, and the democratic potential of online political discussion groups:

Abstract: The proponents of cyberspace promise that online discourse will increase political participation and pave the road for a democratic utopia. This article explores the potential for civil discourse in cyberspace by examining the level of civility in 287 discussion threads in political newsgroups. While scholars often use civility and politeness interchangeably, this study argues that this conflation ignores the democratic merit of robust and heated discussion. Therefore, civility was defined in a broader sense, by identifying as civil behaviors that enhance democratic conversation. In support of this distinction, the study results revealed that most messages posted on political newsgroups were civil, and further suggested that because the absence of face-to-face communication fostered more heated discussion, cyberspace might actually promote Lyotard’s vision of democratic emancipation through disagreement and anarchy (Lyotard, 1984). Thus, this study supported the internet’s potential to revive the public s...

Is Knowledge Power? Knowledge Flows, Subsidiary Power and Rent-Seeking within MNCs

Abstract: In recent years, as multinational corporation (MNC) subsidiaries have become more closely linked to international networks, their knowledge intensity has risen, and some of their R&D has gained a more creative role. Simultaneously, and often connectedly, many subsidiaries have acquired considerable strategic independence in all aspects of their operations, and therefore are able to exercise considerable intra-firm bargaining power to influence the distribution of the firm’s resources. In this context, we suggest that intra-MNC knowledge flows are a key determinant of subsidiary bargaining power. We argue that subsidiary managers can exploit such power to pursue their own ends. Such rent-seeking behavior is implicit in much of the literature on managerialism, but our analysis suggests that such behavior can now occur in headquarters–subsidiary and subsidiary–subsidiary relations. Thus subsidiary strategic independence, designed to enhance the competitiveness of outputs (market knowledge) and inputs (asset-seeking and learning), can be corroded when the pursuit of subsidiary objectives encourages rent-seeking. Empirical analysis of a sample of high-technology subsidiaries in the UK provides strong support for the theory. We examine several avenues whereby the incentives of units within the MNC can be aligned.

A Temporal Analysis of Quarterly Earnings Thresholds: Propensities and Valuation Consequences

Abstract: Applying a Burgstahler and Dichev (1997)/Degeorge et al. (1999) type methodology to quarterly data for the 1985-2002 time period, we show that, since the mid-1990s, but not before then, managers seek to avoid negative quarterly earnings surprises more than to avoid either quarterly losses or quarterly earnings decreases. Our findings suggest that the quarterly earnings threshold hierarchy proposed by Degeorge et al. (1999) does not apply to recent years, and that managers' claim that avoiding quarterly earnings decreases is the threshold they most seek to achieve (Graham et al. 2004) is inconsistent with their actions. We provide an intuitively appealing economic rationale for why the shift in threshold hierarchy occurred; since the mid-1990s, but not before then, investors unambiguously rewarded (penalized) firms for reporting quarterly earnings meeting (missing) analysts' estimates more than they did for meeting (missing) the other two thresholds. We provide several explanations for why investors unambiguously reward firms for reporting quarterly earnings that meet or beat analysts' estimates more than for meeting the other two thresholds late (but not early) in our sample period: increased media coverage given to analyst forecasts, more analyst following, more firms covered by analysts, and temporal increases in both the accuracy and precision of analyst forecasts.

Central role of the P2Y12 receptor in platelet activation

Abstract: The vessel wall contains a continuous lining of endothelium that serves as a barrier between the circulating platelets and the prothrombotic subendothelial matrix (1). Upon vessel injury, the endothelial layer is disrupted and the circulating platelets are exposed to subendothelial proteins such as vWF, collagen, and vitronectin, among others (1). The platelets initially interact with the subendothelium through adhesive receptors, such as GPIb-IX-V receptors, that mediate rolling and tethering of the platelets to vWF at the site of vascular injury. Next, the platelet collagen receptors α2β1 and GPVI mediate a more firm adhesion and cause further platelet activation. These initial interactions with the subendothelium cause the release of contents from the platelet dense granules, which contain platelet agonists such as ADP, and the α-granules, which contain fibrinogen, factor V, and P-selectin (1). The release of the granule contents causes further platelet activation, but it also fuels the coagulation response as a result of the release of factor V and fuels the inflammatory response through the exposure of P-selectin on the platelet surface. The platelet also generates lipid mediators such as thromboxane A2. ADP elicits its effects on the platelet through the P2Y1 and P2Y12 receptors (2), whereas thromboxane A2 activates the thromboxane-prostanoid (TP) receptor on the platelet surface (1). The released dense granule contents cause further platelet activation and recruitment of circulating platelets to the site of injury. Platelets interacting with these mediators also undergo platelet shape change, a process of actin cytoskeletal reorganization that changes the platelets from a disc shape to a round shape with long, filopodial extensions that form a meshwork of platelets in the platelet plug (3). Also, tissue factor is exposed, which initiates the coagulation response that results in formation of thrombin. Thrombin activates platelets via interactions with the proteinase-activated receptor-1 (PAR1) and PAR4 receptors (4) and also cleaves fibrinogen to form fibrin. Fibrin further stabilizes the accumulating platelet plug at the site of injury, resulting in a stable hemostatic plug. Interactions of the platelets with collagen, vWF, ADP, thromboxane A2, and thrombin cause intracellular platelet signaling that leads to the activation of the heterodimeric integrin αIIbβ3, also known as the fibrinogen receptor (5). The intracellular platelet signaling from these agonists causes the fibrinogen receptor to change from a low-affinity state to a high-affinity state that binds fibrinogen (6). Fibrinogen binds to the platelets via the activated fibrinogen receptor, and this cross-linking of platelets to fibrinogen results in platelet aggregates that accumulate and arrest bleeding at the site of injury (Figure ​(Figure1).1). Thus, platelet activation is the product of many signals originating from many receptors, which each contribute to the formation of a platelet plug. Figure 1 The hemostatic process. Upon vessel injury, platelets roll and become tethered to the vessel wall by interactions with vWF and collagen (noted as black strands). These interactions cause platelet shape change, and release of ADP from dense granules. The ... Pathophysiologic conditions, such as atherosclerotic plaque rupture, can lead to aberrant platelet activation resulting in arterial thrombosis, which can cause myocardial infarction and ischemic stroke (6). The importance of ADP in this process has been demonstrated both by antiplatelet drugs that target the P2Y12 receptor (2) and by patients with dysfunctional P2Y12 receptors (7). Antagonism of the P2Y12 receptor with either ticlopidine or clopidogrel is clinically effective in the prevention of myocardial infarction, ischemic stroke, and vascular death (8). Despite the established role of the P2Y12 receptor in the hemostatic response, the full implications of P2Y12 receptor antagonism in the prevention of thrombosis remain incompletely understood. It is hoped that more clinically effective P2Y12 antagonists will prevent the incidence of ischemic events that stem from aberrant platelet activation and therefore will be used as improved and suitable treatments for thrombosis.

Hemispatial neglect Subtypes, neuroanatomy, and disability

Abstract: Objective: To assess the relative frequency of occurrence of motor, perceptual, peripersonal, and personal neglect subtypes, the association of neglect and other related deficits (e.g., deficient nonlateralized attention, anosognosia), and the neuroanatomic substrates of neglect in patients with right hemisphere stroke in rehabilitation settings. Methods: The authors assessed 166 rehabilitation inpatients and outpatients with right hemisphere stroke with measures of neglect and neglect subtypes, attention, motor and sensory function, functional disability, and family burden. Detailed lesion analyses were also performed. Results: Neglect was present in 48% of right hemisphere stroke patients. Patients with neglect had more motor impairment, sensory dysfunction, visual extinction, basic (nonlateralized) attention deficit, and anosognosia than did patients without neglect. Personal neglect occurred in 1% and peripersonal neglect in 27%, motor neglect in 17%, and perceptual neglect in 21%. Neglect severity predicted scores on the Functional Independence Measure and Family Burden Questionnaire more accurately than did number of lesioned regions. Conclusions: The neglect syndrome per se, rather than overall stroke severity, predicts poor outcome in right hemisphere stroke. Dissociations between tasks assessing neglect subtypes support the existence of these subtypes. Finally, neglect results from lesions at various loci within a distributed system mediating several aspects of attention and spatiomotor performance.

Child anxiety treatment: outcomes in adolescence and impact on substance use and depression at 7.4-year follow-up.

Abstract: Research suggests that the sequelae of childhood anxiety disorders, if left untreated, can include chronic anxiety, depression, and substance abuse. The current study evaluated the maintenance of outcomes of children who received a 16-week cognitive-behavioral treatment for primary anxiety disorders (generalized, separation, and social anxiety disorders) an average of 7.4 years earlier. The 86 participants (ages 15 to 22 years; 91% of the original sample) and their parents completed diagnostic interviews and self- and parent-report measures. According to the diagnostic interviews, a meaningful percentage of participants maintained significant improvements in anxiety at long-term follow-up. With regard to sequelae, positive responders to anxiety treatment, as compared with less positive responders, had a reduced amount of substance use involvement and related problems at long-term follow-up. The findings are discussed with regard to child anxiety and some of its sequelae.

Low-dose inhaled nitric oxide in patients with acute lung injury: a randomized controlled trial.

Abstract: ContextInhaled nitric oxide has been shown to improve oxygenation in acute lung injury.ObjectiveTo evaluate the clinical efficacy of low-dose (5-ppm) inhaled nitric oxide in patients with acute lung injury.Design and SettingMulticenter, randomized, placebo-controlled study, with blinding of patients, caregivers, data collectors, assessors of outcomes, and data analysts (triple blind), conducted in the intensive care units of 46 hospitals in the United States. Patients were enrolled between March 1996 and September 1999.PatientsPatients (n = 385) with moderately severe acute lung injury, a modification of the American-European Consensus Conference definition of acute respiratory distress syndrome (ARDS) using a ratio of PaO2 to FiO2 of ≤250, were enrolled if the onset was within 72 hours of randomization, sepsis was not the cause of the lung injury, and the patient had no significant nonpulmonary organ system dysfunction at randomization.InterventionsPatients were randomly assigned to placebo (nitrogen gas) or inhaled nitric oxide at 5 ppm until 28 days, discontinuation of assisted breathing, or death.Main Outcome MeasuresThe primary end point was days alive and off assisted breathing. Secondary outcomes included mortality, days alive and meeting oxygenation criteria for extubation, and days patients were alive following a successful unassisted ventilation test.ResultsAn intent-to-treat analysis revealed that inhaled nitric oxide at 5 ppm did not increase the number of days patients were alive and off assisted breathing (mean [SD], 10.6 [9.8] days in the placebo group and 10.7 [9.7] days in the inhaled nitric oxide group; P = .97; difference, –0.1 day [95% confidence interval, –2.0 to 1.9 days]). This lack of effect on clinical outcomes was seen despite a statistically significant increase in PaO2 that resolved by 48 hours. Mortality was similar between groups (20% placebo vs 23% nitric oxide; P = .54). Days patients were alive following a successful 2-hour unassisted ventilation trial were a mean (SD) of 11.9 (9.9) for placebo and 11.4 (9.8) for nitric oxide patients (P = .54). Days alive and meeting criteria for extubation were also similar: 17.0 placebo vs 16.7 nitric oxide (P = .89).ConclusionInhaled nitric oxide at a dose of 5 ppm in patients with acute lung injury not due to sepsis and without evidence of nonpulmonary organ system dysfunction results in short-term oxygenation improvements but has no substantial impact on the duration of ventilatory support or mortality.

Driven to Tiers: Socioeconomic and Racial Disparities in the Quality of Nursing Home Care

Abstract: Nursing home care is currently a two-tiered system. The lower tier consists of facilities housing mainly Medicaid residents and, as a result, has very limited resources. The nearly 15 percent of U.S. nonhospital-based nursing homes that serve predominantly Medicaid residents have fewer nurses, lower occupancy rates, and more health-related deficiencies. They are more likely to be terminated from the Medicaid/Medicare program, are disproportionately located in the poorest counties, and are more likely to serve African-American residents than are other facilities. The public reporting of quality indicators, intended to improve quality through market mechanisms, may result in driving poor homes out of business and will disproportionately affect nonwhite residents living in poor communities. This article recommends a proactive policy stance to mitigate these consequences of quality competition.

A Survey of Online Harassment at a University Campus

Abstract: This exploratory study of 339 students at the University of New Hampshire found that approximately 10% to 15% of students reported receiving repeated e-mail or Instant Messenger (I-M) messages that “threatened, insulted, or harassed,” and more than half of the students received unwanted pornography. Approximately 7% of students reported online harassment to an authority. Messages originated from strangers, acquaintances, and significant others. No difference in online harassment was found based on demographic variables except sexual orientation. Sexual minority students were more likely to receive online harassment from strangers than were heterosexual students. Implications for further research and for policy/program development are discussed.

Theory and research on desistance from antisocial activity among serious adolescent offenders

Abstract: Improving juvenile court decision making requires information about how serious adolescent offenders desist from antisocial activity. A systematic research agenda on this topic requires consideration of several processes, including normative development in late adolescence, what constitutes desistance, and the factors likely to promote the end of involvement in antisocial behavior and successful adjustment in early adulthood. This article presents an overview of the major points to consider in pursuing this research agenda.

More information from fewer questions: the factor structure and item properties of the original and brief fear of negative evaluation scale.

Abstract: Statistical methods designed for categorical data were used to perform confirmatory factor analyses and item response theory (IRT) analyses of the Fear of Negative Evaluation scale (FNE; D. Watson & R. Friend, 1969) and the Brief FNE (BFNE; M. R. Leary, 1983). Results suggested that a 2-factor model fit the data better for both the FNE and the BFNE, although the evidence was less strong for the FNE. The IRT analyses indicated that although both measures had items with good discrimination, the FNE items discriminated only at lower levels of the underlying construct, whereas the BFNE items discriminated across a wider range. Convergent validity analyses indicated that the straightforwardly-worded items on each scale had significantly stronger relationships with theoretically related measures than did the reverse-worded items. On the basis of all analyses, usage of the straightforwardly-worded BFNE factor is recommended for the assessment of fear of negative evaluation.

Compartmentalization of Gene Expression during Bacillus subtilis Spore Formation

Abstract: Gene expression in members of the family Bacillaceae becomes compartmentalized after the distinctive, asymmetrically located sporulation division. It involves complete compartmentalization of the activities of sporulation-specific sigma factors, sigma(F) in the prespore and then sigma(E) in the mother cell, and then later, following engulfment, sigma(G) in the prespore and then sigma(K) in the mother cell. The coupling of the activation of sigma(F) to septation and sigma(G) to engulfment is clear; the mechanisms are not. The sigma factors provide the bare framework of compartment-specific gene expression. Within each sigma regulon are several temporal classes of genes, and for key regulators, timing is critical. There are also complex intercompartmental regulatory signals. The determinants for sigma(F) regulation are assembled before septation, but activation follows septation. Reversal of the anti-sigma(F) activity of SpoIIAB is critical. Only the origin-proximal 30% of a chromosome is present in the prespore when first formed; it takes approximately 15 min for the rest to be transferred. This transient genetic asymmetry is important for prespore-specific sigma(F) activation. Activation of sigma(E) requires sigma(F) activity and occurs by cleavage of a prosequence. It must occur rapidly to prevent the formation of a second septum. sigma(G) is formed only in the prespore. SpoIIAB can block sigma(G) activity, but SpoIIAB control does not explain why sigma(G) is activated only after engulfment. There is mother cell-specific excision of an insertion element in sigK and sigma(E)-directed transcription of sigK, which encodes pro-sigma(K). Activation requires removal of the prosequence following a sigma(G)-directed signal from the prespore.

A symptom-level examination of parent-child agreement in the diagnosis of anxious youths.

Abstract: Objective To examine parent–child agreement, at the symptom level, in the assessment of anxiety in youths. Differences between agreement at the diagnostic and symptom levels were explored as well as differences in agreement across symptom categories. Differences in the direction of disagreement across symptom categories were also examined. Method Participants were 98 children, 7 to 14 years old (54 boys) who met diagnostic criteria for separation anxiety disorder, social phobia, or generalized anxiety disorder and their parents. Diagnostic and symptom data were obtained using the Anxiety Disorders Interview Schedule for Children and Parents. Results Parent–child agreement at the symptom level was stronger than agreement at the diagnostic level for all three disorders. Parent–child agreement was stronger for observable symptoms than for unobservable symptoms and weaker for school-based symptoms than for non–school-based symptoms. In cases of discrepant symptom reports, the direction of disagreement varied according to the type of symptom. Conclusions These findings buttress the need for a multi-informant approach in the assessment of childhood anxiety. Further, given the low parent–child agreement at the symptom level in the assessment of child anxiety, clinicians may do well to consider employing the “or rule” at the symptom level when integrating discrepant reports.

Social support and demographic correlates of acculturative stress in international students

Abstract: A sample of 141 international students from different U.S. colleges completed surveys related to social support, demographic variables, and acculturative stress. Findings indicated that social support and English proficiency uniquely contribute to the variance in students' acculturative stress. Results also indicated that students who primarily socialized with non-Americans and that students from Asian countries experienced more acculturative stress compared with other subgroups, implications are discussed and suggestions for counseling practice are provided. ********** The United States hosts approximately half of the world's total number of international students. Presently, students representing roughly 170 foreign countries are enrolled in American institutions of higher education. Estimates place international student enrollment in U.S. colleges and universities at around half a million (Zikopoulos, 1993), and this number is expected to increase consistently as U.S. colleges and universities strive to achieve their visions of diversity across a broad range of demographic and cultural dimensions (Hayes & Lin, 1994; Pedersen, 1991). This phenomenon has generated a number of research studies aimed at understanding the experiences of this population. Over the course of their studies, most international students encounter adjustment issues that include acculturative stress. Despite the substantial body of literature that addresses adjustment processes among international students, only a small portion of this literature has, in fact, addressed the issue of acculturative stress. Within this literature, the only variables that have emerged as consistent predictors of international student adjustment are English language proficiency and access to social support. Predictors such as age, gender, ethnicity, and other demographic variables have received only partial or mixed support. Therefore, the purpose of this study was (a) to examine the association of demographic variables with acculturative stress levels to better understand their possible importance, (b) to examine the way in which English language ability and social support may interact to better predict acculturative stress, and (c) to understand the differential influence ethnicity (European vs. Asian) may exert on students' levels of acculturative stress. Acculturation Processes and Outcomes Acculturation is defined as a process of cultural change that results from repeated, direct contact between two distinct cultural groups (Berry, Kim, Minde, & Mok, 1987). A possible result accompanying the process of acculturation is the manifestation of acculturative stress. Acculturative stress is defined as a marked deterioration of the general health status of an individual; it encompasses physiological, psychological, and social aspects that are explicitly linked to the acculturation process. The degree of acculturative stress experienced by an individual can range from mild stress, which gradually improves as the individual adapts, to a debilitating stress that worsens over time (Berry et al., 1987; Williams & Berry, 1991). Most notably, individuals experiencing acculturative stress typically display symptoms of anxiety and depression, which may increase if the individual lacks an effective social support system (Hovey & Magana, 2002). Acculturative Stress and International College Students Although acculturative stress is typically most severe among refugee immigrants, it is surprising that the acculturative stress levels experienced by student sojourners can approach that of refugees (Berry & Kim, 1988). International students are likely to have limited personal resources when they enter the host country and, as a result, are likely to experience considerably greater difficulty acculturating than established ethnic groups (Berry, 1980; Berry & Kim, 1988; Hayes & Lin, 1994; Sykes & Eden, 1985). …

Operational lessons from the pathways to desistance project.

Abstract: Implementing a large, longitudinal study of any sample is a major undertaking. The challenges are compounded when the study involves multiple sites and a high-risk sample. This article outlines the methodology for the Pathways to Desistance study, a multisite, longitudinal study of serious juvenile offenders, and discusses the key operational decisions with the greatest impact on the study design.

Protein flexibility and intrinsic disorder.

Abstract: Comparisons were made among four categories of protein flexibility: (1) low-B-factor ordered regions, (2) high-B-factor ordered regions, (3) short disordered regions, and (4) long disordered regions. Amino acid compositions of the four categories were found to be significantly different from each other, with high-B-factor ordered and short disordered regions being the most similar pair. The high-B-factor (flexible) ordered regions are characterized by a higher average flexibility index, higher average hydrophilicity, higher average absolute net charge, and higher total charge than disordered regions. The low-B-factor regions are significantly enriched in hydrophobic residues and depleted in the total number of charged residues compared to the other three categories. We examined the predictability of the high-B-factor regions and developed a predictor that discriminates between regions of low and high B-factors. This predictor achieved an accuracy of 70% and a correlation of 0.43 with experimental data, outperforming the 64% accuracy and 0.32 correlation of predictors based solely on flexibility indices. To further clarify the differences between short disordered regions and ordered regions, a predictor of short disordered regions was developed. Its relatively high accuracy of 81% indicates considerable differences between ordered and disordered regions. The distinctive amino acid biases of high-B-factor ordered regions, short disordered regions, and long disordered regions indicate that the sequence determinants for these flexibility categories differ from one another, whereas the significantly-greater-than-chance predictability of these categories from sequence suggest that flexible ordered regions, short disorder, and long disorder are, to a significant degree, encoded at the primary structure level.

Relationship Lending: A Survey of the Literature

Abstract: This paper reviews the recent literature on relationship lending First, the effect of relationship lending on firm value is examined in the context of the event studies investigating the impact of announcement of bank loans on stocks of the borrowing firms Second, the effects on funds availability, loan rates, and collateral requirements are appraised Third, the evidence on the impact of the length of the relationship, multiple bank relationships, and distance from the lender are assessed Fourth, the effect of bank consolidation on relationship banking and the role of de novo banks are discussed Finally, the effects of deregulation and technology on community banks are examined The evidence indicates that relationships increase funds availability and reduce loan rates The evidence on the direction and magnitude of the length of relationships is mixed and multiple relationships reduce the value of any single borrower lender relationship Small banks can maintain the advantages of relationship banking in spite of technological changes

Meta analysis of the treatment-related factors of external apical root resorption.

Abstract: Structured Abstract Authors – Segal GR, Schiffman PH, Tuncay OC Objective – To elucidate possible treatment-related etiological factors – such as, duration of treatment and apical displacement – for external root resorption. Design – Meta-analysis of the available English-language literature. Inclusion & Exclusion Criteria – Papers with a sample size >10, fixed appliances, pre- and post-operative radiographs, and apical displacement recorded were included. History of trauma, prior root resorption and endodontic treatment were excluded. Appropriateness of these selections was tested with a ‘funnel plot’ analysis. Outcome Measure – Correlations between root resorption, apical displacement, and treatment duration. Results – Mean apical root resorption was strongly correlated with total apical displacement (r = 0.822) and treatment duration (r = 0.852). Conclusion – The treatment-related causes of root resorption appear to be the total distance the apex had moved and the time it took.

Diversity and dynamics of a north atlantic coastal Vibrio community

Abstract: Vibrios are ubiquitous marine bacteria that have long served as models for heterotrophic processes and have received renewed attention because of the discovery of increasing numbers of facultatively pathogenic strains. Because the occurrence of specific vibrios has frequently been linked to the temperature, salinity, and nutrient status of water, we hypothesized that seasonal changes in coastal water bodies lead to distinct vibrio communities and sought to characterize their level of differentiation. A novel technique was used to quantify shifts in 16S rRNA gene abundance in samples from Barnegat Bay, N.J., collected over a 15-month period. Quantitative PCR (QPCR) with primers specific for the genus Vibrio was combined with separation and quantification of amplicons by constant denaturant capillary electrophoresis (CDCE). Vibrio populations identified by QPCR-CDCE varied between summer and winter samples, suggesting distinct warm-water and year-round populations. Identification of the CDCE populations by cloning and sequencing of 16S rRNA genes from two summer and two winter samples confirmed this distinction. It further showed that CDCE populations corresponded in most cases to approximately 98% rRNA similarity groups and suggested that the abundance of these follows temperature trends. Phylogenetic comparison yielded closely related cultured and often pathogenic representatives for most sequences, and the temperature ranges of these isolates confirmed the trends seen in the environmental samples. Overall, this suggests that temperature is a good predictor of the occurrence of closely related vibrios but that considerable microdiversity of unknown significance coexists within this trend.

Estimating the degree of emergency department overcrowding in academic medical centers: results of the National ED Overcrowding Study (NEDOCS).

Abstract: Objectives: No single universal definition of emergency department (ED) overcrowding exists. The authors hypothesize that a previously developed site-sampling form for academic ED overcrowding is a valid model to quantify overcrowding in academic institutions and can be used to develop a validated short form that correlates with overcrowding. Methods: A 23-question site-sampling form was designed based on input from academic physicians at eight medical schools representative of academic EDs nationwide. A total of 336 site-samplings at eight academic medical centers were conducted at 42 computer-generated random times over a three-week period by independent observers at each site. These sampling times ranged from very slow to severely overcrowded. The outcome variable was the degree of overcrowding as assessed by the charge nurse and ED physicians. The full model consisted of objective data that were obtained by counting the number of patients, determining patients' waiting times, and obtaining information from registration, triage, and ancillary services. Specific objective data were indexed to site-specific demographics. The outcome and objective data were compared using a multiple linear regression to determine predictive validity of the full model. A five-question reduced model was calculated using a backward stepdown procedure. Predictive validity and relationships between the outcome and objective data were assessed using a mixed-effects linear regression model, treating center as random effect. Results: Overcrowding occurred 12% to 73% of the time (mean, 35%), with two hospitals being overcrowded more than 50% of the time. Comparison of objective and outcome data resulted in an R2 of 0.49 (p < 0.001), indicating a good degree of predictive validity. A reduced five-question model predicted the full model with 88% accuracy. Conclusions: Overcrowding varied widely between academic centers during the study period. Results of a five-question reduced model are valid and accurate in predicting the degree of overcrowding in academic centers.