2,364 research outputs found
Complex Correspondence Principle
Quantum mechanics and classical mechanics are two very different theories,
but the correspondence principle states that quantum particles behave
classically in the limit of high quantum number. In recent years much research
has been done on extending both quantum mechanics and classical mechanics into
the complex domain. This letter shows that these complex extensions continue to
exhibit a correspondence, and that this correspondence becomes more pronounced
in the complex domain. The association between complex quantum mechanics and
complex classical mechanics is subtle and demonstrating this relationship
prequires the use of asymptotics beyond all orders.Comment: 4 pages, 6 figure
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Approximately Men
Approximately Men is the first section of a novel. It explores queer masculinities, femininities, and the liminal spaces that foster self-actualization. The voice in this piece attempts to reconcile the individual with the expectations of that individual, and does its best to not intervene. The following is an excerpt:
āYou know,ā Andrew said before letting out a breath of smoke. āI really do like Kerouac. He spends pages just listing the things he sees, like rotting peanut butter and empty boxes of Tide detergent. I canāt imagine those were fun bits to read at the time he wrote them, but theyāre so interesting now, a few generations later, thinking of what trash surrounded people so long ago. I want to live my life with his awareness. Nicholas might be right that we all just try to live out other peopleās great stories, but I canāt bring myself to believe thatās bad. Sometimes in order to have an exciting day, you just have to convince yourself to perceive it that way. I donāt think itās a crime for us to take a shitty life and convince ourselves itās amazing.ā
Ethan took the joint from Andrewās hand, and then slipped his free hand into Andrewās and sucked a mouthful of adventure into his lungs as he sat on a warm rock and felt the hairs on the insides of his thighs start to crisp and stopped thinking about his place in the world, letting just enough room into his mind for him to think instead about the things in life that exist only for a moment but last so much longer before he let go of Andrewās hand and lay his own across his naked lap
Juvenile Secure Confinement and Recidivism Risk: A Propensity Score Matching Approach
Juvenile crime is a serious issue in the United States. Juveniles, those who are under 18 years of age, account for approximately 24% of the population (Census Bureau 2014). This segment of the population is responsible for over 10% of all crime committed in the United States (FBI 2012). Although secure confinement has been identified as one of the most significant contributors to a juvenileās future risk of recidivism (Bezruki, Varana, and Hill 1999), few studies have directly examined the link between juvenile secure confinement and recidivism. Using official data from Montanaās Juvenile Court Accountability and Tracking System (JCATS) (n=2,897), this study contributes to the literature. The findings are based on propensity score matching to obtain a more comprehensive estimate of the influence placement in secure confinement has on a juvenileās risk of recidivism. In the investigation, recidivism refers to involvement in delinquency within one year, following juvenile court intervention, including release from secure confinement. Close to 70% of juveniles released from secure confinement are involved in recidivism within one year (Bezruki, Varana, and Hill 1999). Propensity score matching approximates the conditions of a controlled experiment. Treatment can include any form of intentional intervention, in this case, placement in secure confinement. Treated cases are matched to non-treated cases based on their propensity to receive treatment (Apel and Sweeten 2010). This statistical analysis eliminates some of the problems of causal inference by ensuring that matched individuals are statistically equivalent. While controlling for covariates related to juvenile recidivism, propensity score matching allows for the estimation of the causal effect of treatment (Guo and Fraser 2015). Conclusions from this research will inform practitioners in the area of juvenile justice on the realities of a practice that has been described as dangerous (Holman and Ziedenberg 2006). Practitioners and researchers alike will be interested in the unique effect of a placement in secure confinement on a juvenileās risk of recidivism. In addition, results from prior studies contrasted with results from this investigation have the potential to inform other researchers of a more valuable tool for analyzing quasi-experimental data
A task and performance analysis of endoscopic submucosal dissection (ESD) surgery
BACKGROUND:
ESD is an endoscopic technique for en bloc resection of gastrointestinal lesions. ESD is a widely-used in Japan and throughout Asia, but not as prevalent in Europe or the US. The procedure is technically challenging and has higher adverse events (bleeding, perforation) compared to endoscopic mucosal resection. Inadequate training platforms and lack of established training curricula have restricted its wide acceptance in the US. Thus, we aim to develop a Virtual Endoluminal Surgery Simulator (VESS) for objective ESD training and assessment. In this work, we performed task and performance analysis of ESD surgeries.
METHODS:
We performed a detailed colorectal ESD task analysis and identified the critical ESD steps for lesion identification, marking, injection, circumferential cutting, dissection, intraprocedural complication management, and post-procedure examination. We constructed a hierarchical task tree that elaborates the order of tasks in these steps. Furthermore, we developed quantitative ESD performance metrics. We measured task times and scores of 16 ESD surgeries performed by four different endoscopic surgeons.
RESULTS:
The average time of the marking, injection, and circumferential cutting phases are 203.4 (Ļ: 205.46), 83.5 (Ļ: 49.92), 908.4 s. (Ļ: 584.53), respectively. Cutting the submucosal layer takes most of the time of overall ESD procedure time with an average of 1394.7 s (Ļ: 908.43). We also performed correlation analysis (Pearson's test) among the performance scores of the tasks. There is a moderate positive correlation (Rā=ā0.528, pā=ā0.0355) between marking scores and total scores, a strong positive correlation (Rā=ā0.7879, pā=ā0.0003) between circumferential cutting and submucosal dissection and total scores. Similarly, we noted a strong positive correlation (Rā=ā0.7095, pā=ā0.0021) between circumferential cutting and submucosal dissection and marking scores.
CONCLUSIONS:
We elaborated ESD tasks and developed quantitative performance metrics used in analysis of actual surgery performance. These ESD metrics will be used in future validation studies of our VESS simulator
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A randomised phase I study of etrolizumab (rhuMAb Ī²7) in moderate to severe ulcerative colitis.
ObjectiveEtrolizumab (rhuMAb Ī²7, anti-Ī²7, PRO145223) is a humanised monoclonal antibody targeting the Ī²7 subunit of the heterodimeric integrins Ī±4Ī²7 and Ī±EĪ²7, which are implicated in leucocyte migration and retention in ulcerative colitis (UC). This randomised phase I study evaluated the safety and pharmacology of etrolizumab in patients with moderate to severe UC.DesignIn the single ascending dose (SAD) stage, etrolizumab (0.3, 1.0, 3.0, 10 mg/kg intravenous, 3.0 mg/kg subcutaneous (SC) or placebo) was administered 4:1 (n=25) in each cohort. In the multiple dose (MD) stage, new patients received monthly etrolizumab (0.5 mg/kg SC (n=4), 1.5 mg/kg SC (n=5), 3.0 mg/kg SC (n=4), 4.0 mg/kg intravenous (n=5)) or placebo (n=5). The pharmacokinetics was studied and Mayo Clinic Score evaluated at baseline, day 29 (SAD), and days 43 and 71 (MD).ResultsIn the SAD stage, there were no dose limiting toxicities, infusion or injection site reactions. Two impaired wound healing serious adverse events occurred in two patients receiving etrolizumab. In the MD stage, there were no dose limiting toxicities, and no infusion or injection site reactions. Headache was the most common adverse event, occurring more often in etrolizumab patients. Antietrolizumab antibodies were detected in two subjects. The duration of Ī²7 receptor full occupancy was dose related. A clinical response was observed in 12/18 patients, and clinical remission in 3/18 patients treated with etrolizumab in the MD stage, compared with 4/5 and 1/5 placebo patients, respectively.ConclusionEtrolizumab is well tolerated in moderate to severe UC. Further investigation is warranted
Gene Splicing of an Invertebrate Beta Subunit (LCav?) in the N-Terminal and HOOK Domains and Its Regulation of LCav1 and LCav2 Calcium Channels
The accessory beta subunit (CavĪ²) of calcium channels first appear in the same genome as Cav1 L-type calcium channels in single-celled coanoflagellates. The complexity of this relationship expanded in vertebrates to include four different possible CavĪ² subunits (Ī²1, Ī²2, Ī²3, Ī²4) which associate with four Cav1 channel isoforms (Cav1.1 to Cav1.4) and three Cav2 channel isoforms (Cav2.1 to Cav2.3). Here we assess the fundamentally-shared features of the CavĪ² subunit in an invertebrate model (pond snail Lymnaea stagnalis) that bears only three homologous genes: (LCav1, LCav2, and LCavĪ²). Invertebrate CavĪ² subunits (in flatworms, snails, squid and honeybees) slow the inactivation kinetics of Cav2 channels, and they do so with variable N-termini and lacking the canonical palmitoylation residues of the vertebrate Ī²2a subunit. Alternative splicing of exon 7 of the HOOK domain is a primary determinant of a slow inactivation kinetics imparted by the invertebrate LCavĪ² subunit. LCavĪ² will also slow the inactivation kinetics of LCav3 T-type channels, but this is likely not physiologically relevant in vivo. Variable N-termini have little influence on the voltage-dependent inactivation kinetics of differing invertebrate CavĪ² subunits, but the expression pattern of N-terminal splice isoforms appears to be highly tissue specific. Molluscan LCavĪ² subunits have an N-terminal āAā isoform (coded by exons: 1a and 1b) that structurally resembles the muscle specific variant of vertebrate Ī²1a subunit, and has a broad mRNA expression profile in brain, heart, muscle and glands. A more variable āBā N-terminus (exon 2) in the exon position of mammalian Ī²3 and has a more brain-centric mRNA expression pattern. Lastly, we suggest that the facilitation of closed-state inactivation (e.g. observed in Cav2.2 and CavĪ²3 subunit combinations) is a specialization in vertebrates, because neither snail subunit (LCav2 nor LCavĪ²) appears to be compatible with this observed property
āWe need to get together and make ourselves heardā: everyday online spaces as incubators of political action
This article examines to what extent, and how, people engaging in political talk within ānon-politicalā discussion forums ā online lifestyle communities ā leads to political (or personal) action or calls-to-action. The analysis is framed in the context of wider questions of citizenship, civic engagement and political mobilization. To capture everyday political talk amongst citizens requires us to move beyond the now widely analysed online spaces of formal politics. Instead, we focus on online third spaces concerning lifestyle issues such as parenting, personal finance and popular culture. Drawing on a content analysis of three popular UK-based discussion forums over the course of five years (2010ā2014), we found that (for two of the three cases) such spaces were more than just talking shops. Rather they were spaces where political actions not only emerged, but where they seemed to be cultivated. Discussions embedded in the personal lives of participants often developed ā through talk ā into political actions aimed at government (or other) authorities. The article sheds light on the contributing factors and processes that (potentially) trigger and foster action emerging from political talk and provides insight into the mobilization potential of third spaces
String windings in the early universe
We study string dynamics in the early universe. Our motivation is the
proposal of Brandenberger and Vafa, that string winding modes may play a key
role in decompactifying three spatial dimensions. We model the universe as a
homogeneous but anisotropic 9-torus filled with a gas of excited strings. We
adopt initial conditions which fix the dilaton and the volume of the torus, but
otherwise assume all states are equally likely. We study the evolution of the
system both analytically and numerically to determine the late-time behavior.
We find that, although dynamical evolution can indeed lead to three large
spatial dimensions, such an outcome is not statistically favored.Comment: 26 pages, LaTeX, 4 eps figure
Weak decay of uniformly accelerated protons and related processes
We investigate the weak interaction emission of spin-1/2 fermions from
accelerated currents. As particular applications, we analyze the decay of
uniformly accelerated protons and neutrons, and the neutrino-antineutrino
emission from uniformly accelerated electrons. The possible relevance of our
results to astrophysics is also discussed.Comment: 16 pages (REVTEX), 6 figures, to appear in Physical Review
Longitudinal algorithms to estimate cardiorespiratory fitness: associations with nonfatal cardiovascular disease and disease-specific mortality
Objectives This study sought to determine the capacity of cardiorespiratory fitness (CRF) algorithms without exercise testing to predict the risk for nonfatal cardiovascular disease (CVD) events and disease-specific mortality. Background Cardiorespiratory fitness (CRF) is not routinely measured, as it requires trained personnel and specialized equipment. Methods Participants were 43,356 adults (21% women) from the Aerobics Center Longitudinal Study, followed up between 1974 and 2003. Estimated CRF was determined on the basis of sex, age, body mass index, waist circumference, resting heart rate, physical activity level, and smoking status. Actual CRF was measured by a maximal treadmill test. Risk reduction per 1-metabolic equivalent increase, discriminative ability (c statistic), and net reclassification improvement were determined. Results During a median follow-up of 14.5 years, 1,934 deaths occurred, 627 due to CVD. In a subsample of 18,095 participants, 1,049 cases of nonfatal CVD events were ascertained. After adjustment for potential confounders, both measured and estimated CRF were inversely associated with risks for all-cause mortality, CVD-related mortality and nonfatal CVD events in men, and all-cause mortality and nonfatal CVD events in women. The risk reduction per 1-metabolic equivalent increase ranged from approximately 10% to 20%. Measured CRF had a slightly better discriminative ability (c statistic) than did estimated CRF, and the net reclassification improvement values in measured CRF versus estimated CRF were 12.3% in men (p < 0.05) and 19.8% in women (p < 0.001). Conclusions These CRF algorithms utilized information routinely collected to obtain an estimate of CRF, which provides a valid indication of health status. In addition to identifying people at risk, this method can provide more appropriate exercise recommendations that reflect initial CRF levels
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