1,998 research outputs found
Construction at work: Multiple identities scaffold professional identity development in academia
This is the final version. Available on open access from Frontiers Media via the DOI in this recordIdentity construction - the process of creating and building a new future self - is an integral part of a person's professional career development. However, at present we have little understanding of the psychological mechanisms that underpin this process. Likewise, we have little understanding of the barriers that obstruct it, and which thus may contribute to inequality in career outcomes. Using a social identity lens, and particularly the Social Identity Model of Identity Change (SIMIC), we explore the process of academic identity construction among doctoral students. Through thematic analysis of semi-structured interviews with 22 Ph.D. candidates, we observe that the identity construction process relies on a person's perception of a navigable pathway between their current self and their future self. Importantly, participants who were able to access multiple identity resources were more likely to perceive a navigable pathway to a future professional self (e.g., as an academic), unless they perceived these identities to be incompatible with those held by leading members of the profession (e.g., their supervisors). This research suggests that the identities that people are able to access as they progress in their careers may play an important role in their ongoing professional identity construction and career success.Australian Research Counci
Daily and Seasonal Variation in the Spectral Composition of Light Exposure in Humans
Light is considered the most potent synchronizer of the human circadian system and exerts many other non-image-forming effects, including those that affect brain function. These effects are mediated in part by intrinsically photosensitive retinal ganglion cells that express the photopigment melanopsin. The spectral sensitivity of melanopsin is greatest for blue light at approximately 480 nm. At present, there is little information on how the spectral composition of light to which people are exposed varies over the 24 h period and across seasons. Twenty-two subjects, aged 22±4 yrs (mean±SD) participated during the winter months (November–February), and 12 subjects aged 25±3 yrs participated during the summer months (April–August). Subjects wore Actiwatch-RGB monitors, as well as Actiwatch-L monitors, for seven consecutive days while living in England. These monitors measured activity and light exposure in the red, green, and blue spectral regions, in addition to broad-spectrum white light, with a 2 min resolution. Light exposure during the day was analyzed for the interval between 09:00 and 21:00 h. The time course of white-light exposure differed significantly between seasons (p = 0.0022), with light exposure increasing in the morning hours and declining in the afternoon hours, and with a more prominent decline in the winter. Overall light exposure was significantly higher in summer than winter (p = 0.0002). Seasonal differences in the relative contribution of blue-light exposure to overall light exposure were also observed (p = 0.0006), in particular during the evening hours. During the summer evenings (17:00–21:00 h), the relative contribution of blue light was significantly higher (p < 0.0001) (40.2±1.1%) than during winter evenings (26.6±0.9%). The present data show that in addition to overall light exposure, the spectral composition of light exposure varies over the day and with season
The barrel DIRC of PANDA
Cooled antiproton beams of unprecedented intensities in the momentum range of 1.5-15 GeV/c will be used for the PANDA experiment at FAIR to perform high precision experiments in the charmed quark sector. The PANDA detector will investigate antiproton annihilations with beams in the momentum range of 1.5 GeV/c to 15 GeV/c on a fixed target. An almost 4π acceptance double spectrometer is divided in a forward spectrometer and a target spectrometer. The charged particle identification in the latter is performed by ring imaging Cherenkov counters employing the DIRC principle
The barrel DIRC of PANDA
Cooled antiproton beams of unprecedented intensities in the momentum range of 1.5-15 GeV/c will be used for the PANDA experiment at FAIR to perform high precision experiments in the charmed quark sector. The PANDA detector will investigate antiproton annihilations with beams in the momentum range of 1.5 GeV/c to 15 GeV/c on a fixed target. An almost 4π acceptance double spectrometer is divided in a forward spectrometer and a target spectrometer. The charged particle identification in the latter is performed by ring imaging Cherenkov counters employing the DIRC principle
Status of the PANDA barrel DIRC
The PANDA experiment at the future Facility for Antiproton and Ion Research in Europe GmbH (FAIR) at GSI, Darmstadt will study fundamental questions of hadron physics and QCD using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c. Hadronic PID in the barrel region of the PANDA detector will be provided by a DIRC (Detection of Internally Reflected Cherenkov light) counter. The design is based on the successful BABAR DIRC with several key improvements, such as fast photon timing and a compact imaging region. Detailed Monte Carlo simulation studies were performed for DIRC designs based on narrow bars or wide plates with a variety of focusing solutions. The performance of each design was characterized in terms of photon yield and single photon Cherenkov angle resolution and a maximum likelihood approach was used to determine the π/K separation. Selected design options were implemented in prototypes and tested with hadronic particle beams at GSI and CERN. This article describes the status of the design and R&D for the PANDA Barrel DIRC detector, with a focus on the performance of different DIRC designs in simulation and particle beams
From Demonstrations to Task-Space Specifications:Using Causal Analysis to Extract Rule Parameterization from Demonstrations
Learning models of user behaviour is an important problem that is broadly
applicable across many application domains requiring human-robot interaction.
In this work, we show that it is possible to learn generative models for
distinct user behavioural types, extracted from human demonstrations, by
enforcing clustering of preferred task solutions within the latent space. We
use these models to differentiate between user types and to find cases with
overlapping solutions. Moreover, we can alter an initially guessed solution to
satisfy the preferences that constitute a particular user type by
backpropagating through the learned differentiable models. An advantage of
structuring generative models in this way is that we can extract causal
relationships between symbols that might form part of the user's specification
of the task, as manifested in the demonstrations. We further parameterize these
specifications through constraint optimization in order to find a safety
envelope under which motion planning can be performed. We show that the
proposed method is capable of correctly distinguishing between three user
types, who differ in degrees of cautiousness in their motion, while performing
the task of moving objects with a kinesthetically driven robot in a tabletop
environment. Our method successfully identifies the correct type, within the
specified time, in 99% [97.8 - 99.8] of the cases, which outperforms an IRL
baseline. We also show that our proposed method correctly changes a default
trajectory to one satisfying a particular user specification even with unseen
objects. The resulting trajectory is shown to be directly implementable on a
PR2 humanoid robot completing the same task.Comment: arXiv admin note: substantial text overlap with arXiv:1903.0126
Endoscopic and surgical treatment outcomes of colitis-associated advanced colorectal neoplasia:a multicenter cohort study
BACKGROUND: Inflammatory bowel disease (IBD) patients are at increased risk of advanced neoplasia (high-grade dysplasia or colorectal cancer). The authors aimed to (1) assess synchronous and metachronous neoplasia following (sub)total or proctocolectomy, partial colectomy or endoscopic resection for advanced neoplasia in IBD, and (2) identify factors associated with treatment choice. MATERIAL AND METHODS: In this retrospective multicenter cohort study, the authors used the Dutch nationwide pathology databank (PALGA) to identify patients diagnosed with IBD and colonic advanced neoplasia (AN) between 1991 and 2020 in seven hospitals in the Netherlands. Logistic and Fine & Gray's subdistribution hazard models were used to assess adjusted subdistribution hazard ratios for metachronous neoplasia and associations with treatment choice. RESULTS: The authors included 189 patients (high-grade dysplasia n =81; colorectal cancer n =108). Patients were treated with proctocolectomy ( n =33), (sub)total colectomy ( n =45), partial colectomy ( n =56) and endoscopic resection ( n =38). Partial colectomy was more frequently performed in patients with limited disease and older age, with similar patient characteristics between Crohn's disease and ulcerative colitis. Synchronous neoplasia was found in 43 patients (25.0%; (sub)total or proctocolectomy n =22, partial colectomy n =8, endoscopic resection n =13). The authors found a metachronous neoplasia rate of 6.1, 11.5 and 13.7 per 100 patient-years after (sub)total colectomy, partial colectomy and endoscopic resection, respectively. Endoscopic resection, but not partial colectomy, was associated with an increased metachronous neoplasia risk (adjusted subdistribution hazard ratios 4.16, 95% CI 1.64-10.54, P <0.01) compared with (sub)total colectomy. CONCLUSION: After confounder adjustment, partial colectomy yielded a similar metachronous neoplasia risk compared to (sub)total colectomy. High metachronous neoplasia rates after endoscopic resection underline the importance of strict subsequent endoscopic surveillance.</p
Endoscopic and surgical treatment outcomes of colitis-associated advanced colorectal neoplasia:a multicenter cohort study
BACKGROUND: Inflammatory bowel disease (IBD) patients are at increased risk of advanced neoplasia (high-grade dysplasia or colorectal cancer). The authors aimed to (1) assess synchronous and metachronous neoplasia following (sub)total or proctocolectomy, partial colectomy or endoscopic resection for advanced neoplasia in IBD, and (2) identify factors associated with treatment choice.MATERIAL AND METHODS: In this retrospective multicenter cohort study, the authors used the Dutch nationwide pathology databank (PALGA) to identify patients diagnosed with IBD and colonic advanced neoplasia (AN) between 1991 and 2020 in seven hospitals in the Netherlands. Logistic and Fine & Gray's subdistribution hazard models were used to assess adjusted subdistribution hazard ratios for metachronous neoplasia and associations with treatment choice.RESULTS: The authors included 189 patients (high-grade dysplasia n =81; colorectal cancer n =108). Patients were treated with proctocolectomy ( n =33), (sub)total colectomy ( n =45), partial colectomy ( n =56) and endoscopic resection ( n =38). Partial colectomy was more frequently performed in patients with limited disease and older age, with similar patient characteristics between Crohn's disease and ulcerative colitis. Synchronous neoplasia was found in 43 patients (25.0%; (sub)total or proctocolectomy n =22, partial colectomy n =8, endoscopic resection n =13). The authors found a metachronous neoplasia rate of 6.1, 11.5 and 13.7 per 100 patient-years after (sub)total colectomy, partial colectomy and endoscopic resection, respectively. Endoscopic resection, but not partial colectomy, was associated with an increased metachronous neoplasia risk (adjusted subdistribution hazard ratios 4.16, 95% CI 1.64-10.54, P <0.01) compared with (sub)total colectomy.CONCLUSION: After confounder adjustment, partial colectomy yielded a similar metachronous neoplasia risk compared to (sub)total colectomy. High metachronous neoplasia rates after endoscopic resection underline the importance of strict subsequent endoscopic surveillance.</p
The analysis of relapse-free survival curves: implications for evaluating intensive systemic adjuvant treatment regimens for breast cancer
Results of adjuvant dose intensification studies in patients with localised breast cancer have raised questions regarding the clinical usefulness of this treatment strategy. Here, we develop and fit a natural history model for the time to clinical tumour recurrence as a function of the number of involved lymph nodes, and derive plausible predictions of the effects of dose intensification under various conditions. The time to tumour recurrence is assumed to depend on the residual postoperative micrometastatic burden of tumour, the fractional reduction of residual tumour burden (RTB) by treatment, and the rate of regrowth of the RTB to a clinically detectable size. It is assumed that a proportion of micrometastatic tumours are unresponsive to adjuvant chemotherapy even at maximal dose intensity. Data fitted included the San Antonio Cancer Institute (SACI) database of untreated patients, and CALGB #9082, a study comparing a highly intensive and moderately intensity adjuvant regimen in patients with 10+ positive axillary nodes. The proportion of tumours unresponsive to maximally intensive adjuvant treatment is estimated to be 48% (29–67%). The estimated log kill for intermediate-dose therapy from CALGB #9082 was 6.5 logs, compared with 9 logs or greater for high-dose therapy. The model is consistent with a modest but nonnegligible advantage of dose intensification compared with standard therapies in patients with sensitive tumours who have 10+ positive axillary nodes, and suggests that much of this clinical benefit could be achieved using intermediate levels of treatment intensification. The model further suggests that, in patients with fewer than 10 involved axillary nodes, any advantage of treatment intensification over standard therapy would be much reduced, because in patients with smaller tumour burdens of sensitive tumour, a larger proportion of cures achievable with intensified therapy could be achieved as well with standard therapy
Association between proton pump inhibitor therapy and clostridium difficile infection: a contemporary systematic review and meta-analysis.
Abstract
Introduction
Emerging epidemiological evidence suggests that proton pump inhibitor (PPI) acid-suppression therapy is associated with an increased risk of Clostridium difficile infection (CDI).
Methods
Ovid MEDLINE, EMBASE, ISI Web of Science, and Scopus were searched from 1990 to January 2012 for analytical studies that reported an adjusted effect estimate of the association between PPI use and CDI. We performed random-effect meta-analyses. We used the GRADE framework to interpret the findings.
Results
We identified 47 eligible citations (37 case-control and 14 cohort studies) with corresponding 51 effect estimates. The pooled OR was 1.65, 95% CI (1.47, 1.85), I2 = 89.9%, with evidence of publication bias suggested by a contour funnel plot. A novel regression based method was used to adjust for publication bias and resulted in an adjusted pooled OR of 1.51 (95% CI, 1.26–1.83). In a speculative analysis that assumes that this association is based on causality, and based on published baseline CDI incidence, the risk of CDI would be very low in the general population taking PPIs with an estimated NNH of 3925 at 1 year.
Conclusions
In this rigorously conducted systemic review and meta-analysis, we found very low quality evidence (GRADE class) for an association between PPI use and CDI that does not support a cause-effect relationship
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