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Contains fulltext : 237416.pdf (Publisher’s version ) (Open Access) Previous studies have called attention to the fact that popular youth are not immune to peer victimization, suggesting there is heterogeneity in the popularity of victims. Yet, no study to date has determined whether victims with different levels of popularity status can be identified using person-oriented analysis. Such analysis is critically needed to confirm the existence of popular victims. Further, there remains a paucity of research on internalizing indices of such popular victims, especially compared to other victim and non-victim groups. To address this gap in the research literature, the current study used latent profile analysis to identify subgroups of victims based on victimization (self- and peer-report) and popularity (peer-report). This study sought to verify the existence of popular victims and to compare victim subgroups on loneliness and self-esteem. Participants were 804 Dutch adolescents (50.2% boys, Mage = 13.65 years, ranging from 11.29 to 16.75 years). The results revealed six subgroups, including a group of popular self-identified victims. Popular self-identified victims were generally less lonely than other victims, but had higher loneliness and lower self-esteem than non-victims. Implications are discussed for understanding the victimization experiences of high-status youth. 12 p.

It is now rare to find biological, or genetic investigations that do not rely on the tools, data, and thinking drawn from the genomic sciences. Much of this revolution is powered by contemporary sequencing approaches that readily deliver large, genome-wide data sets that not only provide genetic insights but also uniquely report molecular outcomes from experiments that biophysicists are increasingly using for potentiating structural and mechanistic investigations. In this perspective, I describe a path of how biophysical thinking greatly contributed to this revolution in ways that parallel advancements in computer science through discussion of several key inventions, described as “foundational devices.” These discussions also point at the future of how biophysics and the genomic sciences may become more finely integrated for empowering new measurement paradigms for biological investigations.

This short-term, longitudinal study examines evidence that the level of popularity among adolescents’ peer role models exacerbates the emotional impact of mistreatment by peers. We recruited 469 adolescents (255 boys, 214 girls; [Formula: see text] age = 12.7 years) from an ethnically diverse middle school and followed these youth for a 1-year period. We collected identical measurement batteries in two consecutive waves. Participants completed a self-report assessment of depressive symptoms, as well as a peer-nomination inventory identifying victimized and popular classmates. The inventory also included items asking adolescents to identify peers they want to be like, respect, and admire. High popularity levels among peer role models were associated with intensified associations between peer victimization and depressive symptoms. However, these findings held only for boys. Taken together, these results suggest that victimization by peers is most detrimental for adolescent boys who seek to identify with their more socially dominant classmates.

Recent research has revealed that neural networks and other machine learning models are vulnerable to adversarial attacks that aim to subvert their predictions' integrity or privacy by adding a small calculated perturbation to inputs. Further, the adversary can significantly degrade the performance of the model. The number and severity of attacks continues to grow. However, a dearth of techniques robustly defends machine learning models in a computationally inexpensive way. Against this background, we propose an adversarially robust training procedure and objective function for arbitrary neural network architectures. Robustness of neural networks against adversarial attacks on integrity is achieved by augmentation of a novel regularization term. This regularizer penalizes the discrepancy between the representations induced in hidden layers by benign and adversarial data. We benchmark our regularization approach on the Fashion-Mnist and Cifar-10 datasets. Our model is benchmarked against three state-of-the-art defense methods, namely: (i) regularization to the largest eigenvalue in the Fisher information matrix of the activity of the terminal layer, (ii) a higher-level representation guided denoising autoencoder (trained with adversarial examples), and (iii) training an otherwise undefended model on data distorted by additive white Gaussian noise. Our experiments show that the proposed regularizer provides significant improvements in adversarial robustness over both an undefended baseline model as well as the same model defended with other techniques. This result is observed over several adversarial budgets with only a small (but seemingly unavoidable) decline in benign test accuracy.

Field-effect transistors (FETs) combined with a microfluidic system allow for the electrical detection of charged materials moving in a microfluidic channel. Here, we demonstrate trench-shaped silicon FETs with the combination of a microfluidic channel that can be used for simultaneous electrical and optical detection of charged fluorescent beads. The n-channel silicon trench FETs have a maximum transconductance of 1.83 × 10−5 S at near-zero gate bias voltage, which is beneficial for the high sensitivity of electrical detection. The optical transparency and physical robustness of the integrated microfluidic channel are achieved by a polydimethylsiloxane (PDMS)/glass hybrid cover combining the good sealing characteristics of PDMS, and the thin and flat properties of glass. Device evaluation methodologies and measurement approaches are also presented demonstrating a synchronized time-lapse imaging and electronic detection of bead transport. The proposed device and design consideration could advance the promise of electronic sensing to measure potential differences induced by charged analytes.

As the interest in DNA nanotechnology increases, so does the need for larger and more complex DNA structures. In this work we describe two methods of using large, double-stranded (ds) DNA to self-assemble sequence-specific, non-repetitive microscale structures. A model system restructures T7 DNA (40 kb) through sequence-specific biotinylation followed by intramolecular binding to a 40 nm diameter Neutravidin bead to create T7 “rosettes.” This model system informed the creation of “nodal DNA” where “nodes” with single-stranded DNA flaps are attached to a large dsDNA insert so that a complementary oligonucleotide “strap” bridges the two nodes for restructuring to form a DNA “bolo.” In order to do this in high yield, several methodologies were developed, including a protection / deprotection scheme using RNA / RNase H and dialysis chambers that remove excess straps while retaining large DNA molecules. To assess these restructuring processes, the DNA was adsorbed onto supported lipid bilayers, allowing for a visual assay of their structure using single-molecule fluorescence microscopy. Good agreement between the expected and observed fluorescence intensity measurements of the individual features of restructured DNA for both the DNA rosettes and bolos gives us a high degree of confidence that both processes give sequence-specific restructuring of large, dsDNA molecules to create microscale objects.

Electrostatic forces greatly affect the overall dynamics and diffusional activities of suspended charged particles in crowded environments. Accordingly, the concentration of counter- or co-ions in a fluid-''the salt"-determines the range, strength, and order of electrostatic interactions between particles. This environment fosters engineering routes for controlling directed assembly of particles at both the micro- and nanoscale. Here, we analyzed two computational modeling schemes that considered salt within suspensions of charged particles, or polyelectrolytes: discrete and continuum. Electrostatic interactions were included through a Green's function formalism, where the confined fundamental solution for Poisson's equation is resolved by the general geometry Ewald-like method. For the discrete model, the salt was considered as regularized point-charges with a specific valence and size, while concentration fields were defined for each ionic species for the continuum model. These considerations were evolved using Brownian dynamics of the suspended charged particles and the discrete salt ions, while a convection-diffusion transport equation, including the Nernst-Planck diffusion mechanism, accounted for the dynamics of the concentration fields. The salt/particle models were considered as suspensions under slit-confinement conditions for creating crowded "macro-ions", where density distributions and radial distribution functions were used to compare and differentiate computational models. Importantly, our analysis shows that disparate length scales or increased system size presented by the salt and suspended particles are best dealt with using concentration fields to model the ions. These findings were then validated by novel simulations of a semipermeable polyelectrolyte membrane, at the mesoscale, from which ionic channels emerged and enable ion conduction.

Significance Repeated sequences make up approximately two-thirds of the human genome, which become fully accountable when very large DNA molecules are analyzed. Long, single DNA molecules are problematic using common experimental techniques and fluidic devices because of mechanical considerations that include breakage, dealing with the massive size of these coils, or the huge length of stretched DNAs. Accordingly, we harness analyte “issues” as exploitable advantages by invention and characterization of the “molecular gate,” which controls and synchronizes formation of stretched molecules as DNA dumbbells within nanoslit geometries that may also offer new routes to separation. This was accomplished by theoretical studies and experiments leveraging a series of electrical forces acting on DNA molecules, device walls, and the fluid flows within our devices., Very large DNA molecules enable comprehensive analysis of complex genomes, such as human, cancer, and plants because they span across sequence repeats and complex somatic events. When physically manipulated, or analyzed as single molecules, long polyelectrolytes are problematic because of mechanical considerations that include shear-mediated breakage, dealing with the massive size of these coils, or the length of stretched DNAs using common experimental techniques and fluidic devices. Accordingly, we harness analyte “issues” as exploitable advantages by our invention and characterization of the “molecular gate,” which controls and synchronizes formation of stretched DNA molecules as DNA dumbbells within nanoslit geometries. Molecular gate geometries comprise micro- and nanoscale features designed to synergize very low ionic strength conditions in ways we show effectively create an “electrostatic bottle.” This effect greatly enhances molecular confinement within large slit geometries and supports facile, synchronized electrokinetic loading of nanoslits, even without dumbbell formation. Device geometries were considered at the molecular and continuum scales through computer simulations, which also guided our efforts to optimize design and functionalities. In addition, we show that the molecular gate may govern DNA separations because DNA molecules can be electrokinetically triggered, by varying applied voltage, to enter slits in a size-dependent manner. Lastly, mapping the Mesoplasma florum genome, via synchronized dumbbell formation, validates our nascent approach as a viable starting point for advanced development that will build an integrated system capable of large-scale genome analysis.

Although social problems are often seen as a consequence of depression, symptoms of depression may precede negative experiences in the peer group. We focused on the relations between depressive tendencies and subsequent negative social experiences (i.e., unpopularity and peer disliking) in a sample of early adolescents living in urban neighborhoods with extreme levels of gang violence. We followed 285 middle school students (48% girls; average age at initial data collection = 11.51 years old) for a one-year period, with two annual assessments of psychosocial functioning. Self-reported depressive symptoms in 7th grade significantly predicted increases in peer nominated unpopularity in 8th grade. Conversely, depressive symptoms were not associated with increases in being disliked by peers. These results suggest that, in this gang-impacted context, depressive behaviors can influence position in the peer group hierarchy but may not be perceived aversely by peers.

Fusarium oxysporum is a cross-kingdom fungal pathogen that infects plants and humans. Horizontally transferred lineage-specific (LS) chromosomes were reported to determine host-specific pathogenicity among phytopathogenic F. oxysporum. However, the existence and functional importance of LS chromosomes among human pathogenic isolates are unknown. Here we report four unique LS chromosomes in a human pathogenic strain NRRL 32931, isolated from a leukemia patient. These LS chromosomes were devoid of housekeeping genes, but were significantly enriched in genes encoding metal ion transporters and cation transporters. Homologs of NRRL 32931 LS genes, including a homolog of ceruloplasmin and the genes that contribute to the expansion of the alkaline pH-responsive transcription factor PacC/Rim1p, were also present in the genome of NRRL 47514, a strain associated with Fusarium keratitis outbreak. This study provides the first evidence, to our knowledge, for genomic compartmentalization in two human pathogenic fungal genomes and suggests an important role of LS chromosomes in niche adaptation., Zhang, Yang et al. compare a Fusarium oxysporum isolate obtained clinically to a phytopathogenic strain to examine transfer of lineage-specific chromosomes in determining host specificity. They find four unique lineage-specific chromosomes that seem to contribute to fungal adaptation to human hosts.

Victims of bullying are identified as children and adolescents who emerge as disproportionate targets of peer aggression. This chapter delineates the behaviors that typically constitute peer victimization and identifies common attributes, correlates, and features of victimized youths. The authors then explore the roles of gender, age, and ethnic/cultural contexts on shaping the experience of peer victimization among youths. The chapter concludes by describing some potential longer-term implications of victimization including challenges in the areas of psychosocial adjustment, academic functioning, and self-harm. Finally, areas for further inquiry are explored.

Contains fulltext : 221792.pdf (Publisher’s version ) (Open Access) Recent research has highlighted an understudied phenomenon in the peer victimization literature thus far: the overlap between high status (i.e., popularity) and victimization. However, the research on this phenomenon has primarily been cross-sectional. The current investigation uses a longitudinal design to address two questions related to high-status victims. First, the present study examined prospective associations between popularity and two forms of indirect victimization (reputational victimization and exclusion). Second, this study examined elevated aggression as a consequence of high-status youth's victimization (using self- and peer- reports of victimization). Participants were 370 adolescents (Mage = 14.44, range = 14.00-16.00; 56.5% girls) who were followed for 1 year. Both high and low levels of popularity were prospectively associated with reputational victimization. Moreover, popularity moderated the association between self-reported indirect victimization (but not peer-reported indirect victimization) and aggression. The results help build toward a more comprehensive understanding of both victimization and aggression in adolescence. Findings are discussed in terms of implications for a cycle of aggression in youth and the lowered effectiveness of bullying interventions in adolescence. 11 p.

As American school districts become increasingly diverse, understanding the processes that promote positive intergroup relations is a critical task. The role of cross-ethnic friendships is one important factor, given the significance of these reciprocated peer relationships for social development. The current study examines the short-term longitudinal impact of cross-ethnic friendships on peer group attitudes and emotional adjustment. 524 student participants (54.8% female; Mage = 15.06 years, SD = 0.75; 47% Latino, 53% Asian-American) were followed for one year with two spring data collections. Students completed a self-report inventory assessing depressive symptoms and a peer nomination inventory assessed friendship, liking, disliking, popularity, and unpopularity. Cross-ethnic friendships were predictive of positive attitudes toward peers from other ethnic/racial groups and were also linked to declines in depressive symptoms for boys. Moreover, these positive effects did not come at a social cost, as cross-ethnic friendships were not associated with rejection by same-ethnic peers. Cross-ethnic friendships provide a unique environment that contributes to positive intergroup attitudes and beneficial socioemotional development for some youth.

Social media platforms and instant messaging applications have a widespread presence in today’s secondary schools. However, the implications of these ubiquitous communication technologies for adolescent’s social functioning with peers and academic competence in the classroom are not well understood. In fact, research on adolescents’ digital lives has only rarely incorporated direct assessments of adjustment in school environments. The current study addressed these limitations with a school-based data collection. 376 adolescents (Mage = 14.4; 209 girls; including 29.2% Latino/Hispanic, 27.3% White, 28.2% mixed) were recruited from an urban high school and followed for one year. Social reputations were indexed via peer nominations and electronic communication tendencies were assessed using self-report questionnaires. Grade point averages, disciplinary events, and attendance data were obtained from school records. On a cross-sectional basis, frequent use of fashionable social networks (i.e., Instagram, Snapchat, and Twitter) was associated with popular-aggressive social reputations, poor achievement, and rule-breaking behavior. E-mail use, in contrast, was associated with academic competence. Longitudinal analyses were less conclusive because the examined constructs were highly stable across the period of data collection. The full pattern of findings indicates that electronic communication patterns can be a powerful marker of academic and social functioning at school.

In this study, the associations between peer effects and academic functioning in middle adolescence (N = 342; 14-15 years old; 48% male) were investigated longitudinally. Similarity in achievement (grade point averages) and unexplained absences (truancy) was explained by both peer selection and peer influence, net of acceptance, and connectedness. Friendships were formed and maintained when adolescents had low levels of achievement or high levels of truancy. Friends influenced one another to increase rather than decrease in achievement and truancy. Moreover, friends' popularity moderated peer influences in truancy in reciprocal friendships but not in unilateral friendships, whereas friends' acceptance moderated peer influences in achievement in both unilateral and reciprocal friendships. The findings illustrate the dynamic interplay between peer effects and academic functioning.

This longitudinal study examined the psychosocial adjustment of adolescents who affiliate with antisocial crowds in a gang-impacted urban environment. We followed 405 adolescents (219 boys, 186 girls; average age of 11.51 years, SD = .61; 84% Latino, 9% Asian, and 7% other or unclassified) for one academic year. These youth attended a middle school located in an economically distressed neighborhood with documented high rates of gang violence. We assessed crowd membership with a structured focus group procedure. In addition, we administered a peer nomination inventory to assess aggression and social standing, obtained self-reports of depressive symptoms, and derived grade point averages (GPA) directly from school records. Adolescents used gang-related imagery to describe antisocial crowds in their school, referring to “cholos” and “taggers.” Membership in these crowds was associated with aggression and low GPA but, paradoxically, predicted small decreases in depression and increases in popularity over time. Taken together, our results highlight the complex role of affiliations with antisocial crowds in high-risk settings.

Purpose: Enteral nutrition (EN) is often held in patients receiving vasopressor support for septic shock. The rationale for this practice is to avoid mesenteric ischemia. The objective of this study is to evaluate the tolerability of EN in patients with septic shock who require vasopressor support and determine factors associated with tolerance of EN. Materials and Methods: This was a single-center retrospective review of adult patients admitted to the intensive care unit with a diagnosis of septic shock and an order for EN. The primary outcome was EN tolerance. Secondary outcomes included time to initiation of EN from the start of vasopressor(s), length of stay, and mortality. Results: A total of 120 patients were included. Sixty-two percent of patients tolerated EN. The most common reason for intolerance of EN was gastric residuals > 250 mL (74%). No reports of mesenteric ischemia were observed. A multivariate analysis demonstrated that patients with septic shock initiating EN within 48 hours and receiving norepinephrine-equivalent doses of 0.14 μg/kg/min or less were more likely to tolerate EN. Conclusion: Based on our observation, early EN may be tolerated and safely administered in patients with septic shock who are adequately fluid resuscitated and receive doses of < 0.14 μg/kg/min of norepinephrine equivalents.

Summary Aneuploidy and structural variations (SVs) generate cancer genomes containing a mixture of rearranged genomic segments with extensive somatic copy number alterations. However, existing methods can identify either SVs or allele-specific copy number alterations, but not both simultaneously, which provides a limited view of cancer genome structure. Here we introduce Weaver, an algorithm for the quantification and analysis of allele-specific copy numbers of SVs. Weaver uses a Markov Random Field to estimate joint probabilities of allele-specific copy number of SVs and their inter-connectivity based on paired-end whole-genome sequencing data. Weaver also predicts the timing of SVs relative to chromosome amplifications. We demonstrate the accuracy of Weaver using simulations and findings from whole-genome Optical Mapping. We apply Weaver to generate allele-specific copy numbers of SVs for MCF-7 and HeLa cell lines, and identify recurrent SV patterns in 44 TCGA ovarian cancer whole-genome sequencing datasets. Our approach provides a more complete assessment of the complex genomic architectures inherent to many cancer genomes., Graphical abstract, eTOC Blurb A new algorithm that quantifies allele-specific structural variations can greatly improve the analysis of complex genomic alterations in cancer.

Following earlier incomplete and fragmented versions of a genome sequence for the grey mould Botrytis cinerea, a gapless, near-finished genome sequence for B. cinerea strain B05.10 is reported. The assembly comprised 18 chromosomes and was confirmed by an optical map and a genetic map based on approximately 75 000 single nucleotide polymorphism (SNP) markers. All chromosomes contained fully assembled centromeric regions, and 10 chromosomes had telomeres on both ends. The genetic map consisted of 4153 cM and a comparison of the genetic distances with the physical distances identified 40 recombination hotspots. The linkage map also identified two mutations, located in the previously described genes Bos1 and BcsdhB, that conferred resistance to the fungicides boscalid and iprodione. The genome was predicted to encode 11 701 proteins. RNAseq data from >20 different samples were used to validate and improve gene models. Manual curation of chromosome 1 revealed interesting features, such as the occurrence of a dicistronic transcript and fully overlapping genes in opposite orientations, as well as many spliced antisense transcripts. Manual curation also revealed that the untranslated regions (UTRs) of genes can be complex and long, with many UTRs exceeding lengths of 1 kb and possessing multiple introns. Community annotation is in progress.

Research on generational differences in immigrant youths’ academic achievement has yielded conflicting findings. This meta-analysis reconciles discrepant findings by testing meta-analytic moderators. Fifty-three studies provided 74 comparisons on academic outcomes. First- and second-generation youths did not significantly differ on academic achievement (Hedges’s g = .01), and second-generation students performed slightly better than third-or-later–generation peers (g = .12). Moderation tests indicated that second-generation immigrants outperformed first-generation students on standardized tests (g = .20) and earned better grades than third-or-later–generation peers (g = .20). Immigrant advantage was stronger for Asian, low-socioeconomic, and community samples. Immigrant advantage may be overestimated in studies that use self-reported rather than school-reported achievement. Together, our results suggest a small, heterogeneous second-generation immigrant advantage that varies by immigrant population and study characteristics.

The potential of genomic DNA is realized when new modalities are invented that manipulate large DNAs with minimal breakage or loss of sample. Here, we describe a polydimethylsiloxane–polycarbonate membrane device to remove small molecules from a sample while retaining large DNAs. Dialysis rates dramatically change as DNA size in kb (M) increases and DNA dimensions become comparable to pore size, and chain characteristics go from rod-like to Gaussian. Consequently, we describe empirical rates of dialysis, R, as a function of M as falling into two regimes: DNAs ≤ 1 kb show R(M) ∼e - t/τ M (t = time, τM = time constant), while DNAs ≥1.65 kb slowly passage with R(M) ∼M -1.68; such partitioning potentiates single-molecule imaging.

Digital doppelgangers are virtual humans that highly resemble the real self but behave independently. Digital doppelgangers possess great potential to serve as powerful models for behavioral change. An emerging technology, the Rapid Avatar Capture and Simulation (RACAS) system, enables low-cost and high-speed scanning of a human user and creation of a digital doppelganger that is a fully animatable virtual 3D model of the user. We designed a virtual role-playing game, DELTA, that implements a powerful cognitive dissonance-based paradigm for attitudinal and behavioral change, and integrated it with digital doppelgangers to influence a human user's attitude towards sexism on college campuses. In this paper, we discuss the design and evaluation the RACAS system and the DELTA game-based environment. Results indicate the potential impact of the DELTA game-based environment in creating an immersive virtual experience for attitudinal change.

The perpetration and receipt of electronic aggression have largely been assessed with self-report questionnaires. Using a sample of 573 adolescents, the current study compared the psychometric properties of a peer-nomination measure of electronic aggression and victimization to the more widely used self-report approach. Estimates of the reliability, stability, and concordance of peer- and self-report assessments were adequate, mirroring those from research on aggressive exchanges in school. Analyses of validity and utility revealed that peer-nominations, compared to self-reports, provide overlapping and distinct information on adolescents' social, emotional, and academic adjustment. Overall, these findings provide evidence that peer-nominations are a reliable, valid, and useful means for measuring electronic aggression and victimization. Future work will benefit from their incorporation into multi-method assessments.

Multiple myeloma (MM), a malignancy of plasma cells, is characterized by widespread genomic heterogeneity and, consequently, differences in disease progression and drug response. Although recent large-scale sequencing studies have greatly improved our understanding of MM genomes, our knowledge about genomic structural variation in MM is attenuated due to the limitations of commonly used sequencing approaches. In this study, we present the application of optical mapping, a single-molecule, whole-genome analysis system, to discover new structural variants in a primary MM genome. Through our analysis, we have identified and characterized widespread structural variation in this tumor genome. Additionally, we describe our efforts toward comprehensive characterization of genome structure and variation by integrating our findings from optical mapping with those from DNA sequencing-based genomic analysis. Finally, by studying this MM genome at two time points during tumor progression, we have demonstrated an increase in mutational burden with tumor progression at all length scales of variation.

This longitudinal investigation examined interactions between aggression and peer victimization during middle childhood in the prediction of arrest through the adult years for 388 (198 boys, 190 girls) study participants. As part of an ongoing multisite study (i.e., Child Development Project), peer victimization and aggression were assessed via a peer nomination inventory in middle childhood, and juvenile and adult arrest histories were assessed via a self-report questionnaire as well as review of court records. Early aggression was linked to later arrest but only for those youths who were rarely victimized by peers. Although past investigators have viewed youths who are both aggressive and victimized as a high-risk subgroup, our findings suggest that the psychological and behavioral attributes of these children may mitigate trajectories toward antisocial problems.

To compare utilization of CT pulmonary angiogram (CTA) for diagnosis of pulmonary embolism (PE) in an emergency department (ED) with unstructured CT ordering to published rates of CT positivity in other EDs including those employing decision support and to identify pathways for improved utilization via collaboration with our pathology and ED colleagues. Two hundred seventeen patients over a 2.5-month time period who received a CTA for PE were reviewed with exclusion of pediatric patients and all sub-optimal, non-diagnostic, or equivocal scans; 21 were excluded leaving a sample of 196 patients. The rate of PE diagnosis and association of PE positivity with selected factors (D-dimer testing) was assessed. The percentage of cases positive for PE was 10.7 % (21/196) which is similar to the frequently published rate of 10 % in other emergency departments including settings that have studied the use of decision support. D-dimer testing was performed in 40.3 % of cases. In 29.6 % (58/196) of subjects, D-dimer was positive, 10.7 % (21/196) was negative, and 59.7 % (117/196) was not assessed. Prevalence of PE among D-dimer negative (0 %, 0/21) was lower versus positive D-dimer (12.1 %, 7/58) and unknown D-dimer patients (12.0 %, 14/117). D-dimer had 100 % (21/21) negative predictive value for the diagnosis of PE. While this suggests that D-dimer is useful to rule-out PE, due to the small number of patients with PE, the 95 % confidence intervals are wide and the post-test likelihood of PE could be as high as 14 %. The rate of CT positivity for PE in an ED with unstructured CT ordering is similar to that in other published series including as series in which decision support was used. While D-dimer had high negative predictive value, large studies are needed to confirm this high sensitivity and potentially increase its use in ruling out PE without CT and to reduce CT ordering particularly in patients with sufficiently low clinical pre-test probability of PE.