Longitudinal phase space manipulation in energy recovering linac-driven free-electron lasers

Energy recovering an electron beam after it has participated in a free-electron laser (FEL) interaction can be quite challenging because of the substantial FEL-induced energy spread and the energy anti-damping that occurs during deceleration. In the Jefferson Lab infrared FEL driver-accelerator, such an energy recovery scheme was implemented by properly matching the longitudinal phase space throughout the recirculation transport by employing the so-called energy compression scheme. In the present paper,after presenting a single-particle dynamics approach of the method used to energy-recover the electron beam, we report on experimental validation of the method obtained by measurements of the so-called "compression efficiency" and "momentum compaction" lattice transfer maps at different locations in the recirculation transport line. We also compare these measurements with numerical tracking simulations.Comment: 31 pages, 13 figures, submitted to Phys. Rev. Special Topics A&

Examining Processes of Change in an Online Acceptance and Commitment Therapy Dismantling Trial with Distressed College Students

This secondary analysis examined the processes of change from a randomized dismantling trial evaluating the Open (i.e., cognitive defusion, acceptance) and Engaged (i.e., values, committed action) components of acceptance and commitment therapy (ACT). Analyses were conducted with 161 distressed college students randomly assigned to a full online ACT program (Full n=40), online ACT targeting the Open components (Open n=41) or targeting the Engaged components (Engaged n=39), or a waitlist condition (Waitlist n=41). The intervention occurred over six weeks followed by a post-treatment assessment with mental health symptoms as the primary outcome. Consistent with predictions, pre- to post-treatment improvements in global psychological inflexibility, cognitive fusion, acceptance, values, and committed action all predicted pre- to post-treatment improvements in mental health, with most processes continuing to independently predict improvements when included in a single model. The relations between changes in psychological flexibility and mental health were generally equivalent between conditions. Each psychological flexibility process separately mediated improvements in mental health for Engaged versus waitlist and Full versus waitlist conditions. However, global inflexibility, committed action, and values progress did not mediate effects for Open versus waitlist. Overall, results indicate a range of acceptance, defusion, values, and committed action processes are functionally relevant for outcomes with the Engaged components of ACT and Full ACT, but values, committed action, and global psychological inflexibility processes may be more weakly related to the effects of the Open components of ACT alone

A Randomized Trial of Acceptance and Commitment Therapy and Traditional Cognitive-Behavioral Therapy Self-Help Books for Social Anxiety

Background: Self-help resources such as books may help meet critical mental health needs in college students, but there is insufficient evidence on whether and how such books work. This randomized trial compared acceptance and commitment therapy (ACT) and traditional cognitive behavior therapy (tCBT) self-help books for social anxiety, a common concern with notable barriers to treatment seeking. Methods: A sample of college students (n = 102) with social anxiety was randomly assigned to use one of the two self-help books over eight weeks. Results: Improvements were observed in both conditions across all outcomes (social anxiety, general well-being, and social functioning) as well as potential processes of change (cognitive fusion, appraisals of social concerns, and progress toward personal values). Few differences were observed between conditions. Changes in general cognitive fusion consistently predicted outcomes at posttreatment, and anxiety-specific cognitive fusion and concern about negative social interactions also predicted some later outcomes. Conclusions: Use of self-help books to address social anxiety in college students is promising, and addressing cognitive fusion appears to be important

Utilizing Computed Tomography Image Features to Advance Prediction of Radiation Pneumonitis

Improving outcomes for non-small-cell lung cancer patients treated with radiation therapy (RT) requires optimizing the balance between local tumor control and risk of normal tissue toxicity. In approximately 20% of patients, severe acute symptomatic lung toxicity, termed radiation pneumonitis (RP), still occurs. Identifying the individuals at risk of RP prior to or early during treatment offers tremendous potential to improve RT by providing the physician with information to assist in making clinical decisions that enhance therapy. Our central goal for this work was to demonstrate the potential gain in predictive accuracy of normal tissue complication probability models for RP by considering CT-based image features extracted from the normal lung volume. To accomplish this, a software framework was first built to facilitate CT image feature extraction using multiple image analysis methods. Subsequently, we applied the implemented methods towards understanding the temporal change in the normal lung volume during treatment. After identifying a subset of highly reproducible and non-redundant image features, we investigated change in lung features on weekly CT image sets acquired during treatment. While multiple features exhibited significant association with dose, no temporal response was identified and we were unable to produce a predictive model that could outperform simple treatment-related factors. CT-based image features calculated in regional subvolumes and on a voxel-wise basis in the normal lung were explored in the context of RP incidence. There was no clear spatial variation in the considered regionally extracted features or voxel-based feature maps. However, a limited subset of features were significantly associated with RP which may be a useful finding to consider in development of predictive models to assess toxicity risk. We also considered the utility of pre-treatment total normal lung CT features for predicting RP using LASSO logistic regression and were able to successfully demonstrate improved discrimination of RP using such features relative to models constructed with clinical and dosimetric variables only. This is a significant step towards building robust models of RP with image based features that can subsequently be used to achieve personalized RT

Interaction of Tet Repressor with Operator DNA and with Tetracycline Studied by Infrared and Raman Spectroscopy

AbstractTet repressor (TetR) is involved in the most abundant mechanism of tetracycline (Tc) resistance of Gram-negative bacteria. Raman spectra were measured for the class D TetR protein, for an oligodeoxyribonucleotide with sequence corresponding to operator site O1, and for the TetR:oligonucleotide complex. TetR forms a complex with [Ni-Tc]+, which does not bind to operator DNA. Raman and infrared measurements indicate nearly identical conformations of TetR with and without [Ni-Tc]+. Differences between the experimental spectrum of the TetR:operator DNA complex and the computed sum of the component spectra provide direct spectroscopic evidence for changes in DNA backbone torsions and base stacking, rearrangement of protein backbone, and specific contacts between TetR residues and DNA bases. Complex formation is connected with intensity decrease at 1376cm−1 (participation of thymine methyl groups), intensity increase at 1467cm−1 (hydrogen bond formation at guanine N7), decreased intensity ratio I854/I823 (increased hydrophobicity of tyrosine environment), increased intensity at 1363cm−1 (increased hydrophobicity of tryptophan ring environment), differences in the range 670–833cm−1 (changes in B-DNA backbone torsions and base stacking), and decreased intensity of the amide I band (structural rearrangement of TetR backbone consistent with a reduction of the distance between the two binding helices)

Psychological inflexibility and stigma: A meta-analytic review

Stigma is known to have major impacts on the physical and psychological health of many groups. Psychological inflexibility is a psychological process that may help explain the impact of stigma on both self and others. Accordingly, acceptance and commitment therapy (ACT), which targets psychological inflexibility, has been researched as a potential treatment for stigma. In order to provide a comprehensive overview of these issues, this paper offers a systematic review and meta-analysis of the association between psychological inflexibility and stigma, as well as a systematic review of ACT interventions for stigma. The results of the meta-analysis showed a positive, medium-to-large association between psychological inflexibility and stigma measures aggregating across 16 studies. The systematic review of interventions identified 15 studies on ACT interventions for stigma. Initial findings indicate consistent reductions in stigma following ACT interventions, as well as improved outcomes relative to active controls. Data on mediation and moderation, as well as long-term outcomes, are also presented. Implications for conceptualizing and treating stigma, and limitations of the research, are discussed

Evaluating the Effects of Guided Coaching Calls on Engagement and Outcomes for Online Acceptance and Commitment Therapy

Previous research indicates mixed results for guided support with interventions. The current secondary analysis evaluated the effects of phone coaching from a dismantling trial of online acceptance and commitment therapy (ACT) in a sample of 136 distressed college students randomized to one of three versions of an ACT website. Participants were randomized to receive email prompts alone (non-coaching condition) or email plus phone coaching (coaching condition). Results indicated no differences between the coaching and non-coaching conditions on program engagement, program satisfaction, mental health outcomes, and almost all psychological flexibility processes. However, participants in the coaching condition reported stronger pre- to posttreatment improvements in psychological inflexibility than the non-coaching condition. This effect was moderated by ACT component condition, with larger pre- to posttreatment effects from coaching on psychological inflexibility in the values/committed action condition and weaker improvements from coaching in the acceptance/defusion condition. Overall, results indicate online self-guided ACT interventions with email prompts are sufficient for addressing college student mental health and that phone coaching provided minimal additional benefit

Web-based communication tools in a European research project: the example of the TRACE project

The multi-disciplinary and international nature of large European projects requires powerful managerial and communicative tools to ensure the transmission of information to the end-users. One such project is TRACE entitled “Tracing Food Commodities in Europe”. One of its objectives is to provide a communication system dedicated to be the central source of information on food authenticity and traceability in Europe. This paper explores the web tools used and communication vehicles offered to scientists involved in the TRACE project to communicate internally as well as to the public. Two main tools have been built: an Intranet and a public website. The TRACE website can be accessed at http://www.trace.eu.org. A particular emphasis was placed on the efficiency, the relevance and the accessibility of the information, the publicity of the website as well as the use of the collaborative utilities. The rationale of web space design as well as integration of proprietary software solutions are presented. Perspectives on the using of web tools in the research projects are discussed