Synchronization and Characterization of an Ultra-Short Laser for Photoemission and Electron-Beam Diagnostics Studies at a Radio Frequency Photoinjector

A commercially-available titanium-sapphire laser system has recently been installed at the Fermilab A0 photoinjector laboratory in support of photoemission and electron beam diagnostics studies. The laser system is synchronized to both the 1.3-GHz master oscillator and a 1-Hz signal use to trigger the radiofrequency system and instrumentation acquisition. The synchronization scheme and performance are detailed. Long-term temporal and intensity drifts are identified and actively suppressed to within 1 ps and 1.5%, respectively. Measurement and optimization of the laser's temporal profile are accomplished using frequency-resolved optical gating.Comment: 16 pages, 17 figures, Preprint submitted to Elsevie

Evaluating an online support package delivered within a disability unemployment service: study protocol for a randomised controlled feasibility study

Background Mental health problems such as anxiety and depression are known to be higher in those who are unemployed. Cognitive behavioural therapy (CBT) is a recognised support for people with such problems and can improve the ability of people to get back to work.<p></p> Methods/design Participants with symptoms of low mood will be recruited from the disability employment service, Remploy. Participants will receive either immediate or delayed access to an online CBT-based life skills intervention, the “Living Life” package. The primary end point will be at 3 months when the delayed group will be offered the intervention. This feasibility study will test the trial design and assess recruitment, retention, acceptability and adherence, as well as providing efficacy data.<p></p> Discussion The study will inform the design and sample size for a future full randomised controlled trial (RCT) which will be carried out to determine the effectiveness of the online package in improving mood and employment status.<p></p&gt

Predicting middle-distance track and cross-country performances of national and international level adolescent runners

This study evaluated the contribution of physiological data collected during laboratory testing in predicting race performances of trained junior middle-distance track (TK) and cross-country (XC) athletes. Participants performed a submaximal incremental ramp test, followed by an incremental test to exhaustion in a laboratory, with the results used to predict either 800 m TK, 1500 m TK or 4000-6000 m XC race performance. Twenty-eight participants (male (M), 15; female (F), 13) were analysed (age = 17 ± 2 years, height = 1.72 ± 0.08 m, body mass = 58.9 ± 8.9 kg). Performance times (min:s) for 800 m were: M, 1:56.55 ± 0:05.55 and F, 2:14.21 ± 0:03.89; 1500 m: M, 3:51.98 ± 0:07.35 and F 4:36.71 ± 0:16.58; XC: M (4900 ± 741 m), 16:00 ± 01:53; F (4628 ± 670 m), 17:41 ± 02:09. Stepwise regression analysis indicated significant contributions of speed at V̇O2max (sV̇O2max), and heart rate maximum (HRmax) to the prediction of 800 m TK (F(2,15) = 22.51, p <0.001, adjusted R2 = 0.72), sV̇O2max for 1500 m TK (F(1,13) = 36.65, p <0.001, adjusted R2 = 0.72) and V̇O2max, allometrically scaled to body mass and speed at lactate threshold (sLT) for XC (F(2,17) = 25.1, p <0.001, adjusted R2 = 0.72). Laboratory-based physiological measures can explain 72% of the variance in junior TK and XC events, although factors that explain performance alter depending on the race distance and tactics. The factors determining performance in TK and XC events are not interchangeable

The Golgi-resident protease Kex2 acts in conjunction with Prm1 to facilitate cell fusion during yeast mating

The molecular machines that mediate cell fusion are unknown. Previously, we identified a multispanning transmembrane protein, Prm1 (pheromone-regulated membrane protein 1), that acts during yeast mating (Heiman, M.G., and P. Walter. 2000. J. Cell Biol. 151:719–730). Without Prm1, a substantial fraction of mating pairs arrest with their plasma membranes tightly apposed yet unfused. In this study, we show that lack of the Golgi-resident protease Kex2 strongly enhances the cell fusion defect of Prm1-deficient mating pairs and causes a mild fusion defect in otherwise wild-type mating pairs. Lack of the Kex1 protease but not the Ste13 protease results in similar defects. Δkex2 and Δkex1 fusion defects were suppressed by osmotic support, a trait shared with mutants defective in cell wall remodeling. In contrast, other cell wall mutants do not enhance the Δprm1 fusion defect. Electron microscopy of Δkex2-derived mating pairs revealed novel extracellular blebs at presumptive sites of fusion. Kex2 and Kex1 may promote cell fusion by proteolytically processing substrates that act in parallel to Prm1 as an alternative fusion machine, as cell wall components, or both

Assessing the Impact of Metacognitive Post-Reflection Exercises on Problem-Solving Skillfulness

We studied the impact of metacognitive reflections on recently completed work as a way to improve the retention of newly-learned problem-solving techniques. Students video-recorded themselves talking through problems immediately after finishing them, completed ongoing problem-solving strategy maps or problem-sorting exercises, and filled out detailed exam wrappers. We assessed students' problem-solving skillfulness using a combination of validated instruments and final exam questions scored using a rubric that targets problem-solving best practices. We found a small but significant difference between the rubric score distributions for the control and treatment groups. However, a multiple ordered logistic regression using treatment and Force Concept Inventory (FCI) pre-test score as predictors showed that this difference is better explained by the latter. The surprising impact of conceptual preparation on problem-solving skill suggests two things: the importance of remediation for students with insufficient conceptual understanding and the need to consider problem-solving interventions in the context of students' conceptual knowledge base.Comment: 9 pages, 2 figure

3D heritage visualisation and the negotiation of authenticity: the ACCORD project

This article examines the question of authenticity in relation to 3D visualisation of historic objects and monuments. Much of the literature locates their authenticity in the accuracy of the data and/or the realism of the resulting models. Yet critics argue that 3D visualisations undermine the experience of authenticity, disrupting people&rsquo;s access to the materiality, biography and aura of their historic counterparts. The ACCORD project takes questions of authenticity and 3D visualisation into a new arena &ndash; that of community heritage practice &ndash; and uses rapid ethnographic methods to examine whether and how such visualisations acquire authenticity. The results demonstrate that subtle forms of migration and borrowing occur between the original and the digital, creating new forms of authenticity associated with the digital object. Likewise, the creation of digital models mediates the authenticity and status of their original counterparts through the networks of relations in which they are embedded. The current pre-occupation with the binary question of whether 3D digital models are authentic or not obscures the wider work that such objects do in respect to the cultural politics of ownership, attachment, place-making and regeneration. The article both advances theoretical debates and has important implications for heritage visualisation practice

The ACCORD project: Archaeological Community Co-Production of Research Resources

This paper introduces the AHRC funded ACCORD project, a partnership between the Digital Design Studio at the Glasgow School of Art, Archaeology Scotland, the University of Manchester and the RCAHMS. The ACCORD project examines the opportunities and implications of digital visualisation technologies for community engagement and research through the co-creation of 3D models of historic monuments and places. Despite their increasing accessibility, techniques such as laser scanning, 3D modelling and 3D print- ing have remained firmly in the domain of heritage specialists. Expert forms of knowledge and/or professional priorities frame the use of digital visualisation technologies and forms of community-based social value are rarely addressed. Consequently, the resulting digital objects fail to engage communities as a means of researching and representing their heritage. The first part of this paper pres- ents how the ACCORD project seeks to address this gap through the co-design and co-production of an integrated research asset that encompasses social value and engages communities with transformative digital technologies. The second half of this paper (section 4) presents a case study of an ACCORD project based in Argyll which highlights the nature of community relations with expert groups, issues of archaeological authority and the transformative power of co-production using digital recording techniques

Improved bounds for embedding certain configurations in subsets of vector spaces over finite fields

The fourth listed author and Hans Parshall (\cite{IosevichParshall}) proved that if $E \subset {\mathbb F}_q^d$, $d \ge 2$, and $G$ is a connected graph on $k+1$ vertices such that the largest degree of any vertex is $m$, then if $|E| \ge C q^{m+\frac{d-1}{2}}$, for any $t>0$, there exist $k+1$ points $x^1, \dots, x^{k+1}$ in $E$ such that $||x^i-x^j||=t$ if the $i$'th vertex is connected to the $j$'th vertex by an edge in $G$. In this paper, we give several indications that the maximum degree is not always the right notion of complexity and prove several concrete results to obtain better exponents than the Iosevich-Parshall result affords. This can be viewed as a step towards understanding the right notion of complexity for graph embeddings in subsets of vector spaces over finite fields