Ultrashort intense-field optical vortices produced with laser-etched mirrors

We introduce a simple and practical method to create ultrashort intense optical vortices for applications involving high-intensity lasers. Our method utilizes femtosecond laser pulses to laser-etch grating lines into laser-quality gold mirrors. These grating lines holographically encode an optical vortex. We derive mathematical equations for each individual grating line to be etched, for any desired (integer) topological charge. We investigate the smoothness of the etched grooves. We show that they are smooth enough to produce optical vortices with an intensity that is only a few percent lower than in the ideal case. We demonstrate that the etched gratings can be used in a folded version of our 2f-2f setup [Mariyenko et al., Opt. Express 19, 7599 (2005)] to compensate angular dispersion. Lastly, we show that the etched gratings withstand intensities of up to 10^12 W/cm2.Comment: 14 pages, 12 figures, submitted to Optics Expres

Discrimination and Quantification of Glomerular Receptor Subtypes for Atrial Natriuretic Factor (Anf)

Binding sites for atrial natriuretic factor (ANF) were determined on isolated rat glomeruli as well as on glomerular membranes. To define optimal conditions, binding of ANF was investigated varying incubation time, temperature and protein concentration. Binding conditions were found to be best at 4°C for 5 hours with 15 μg of glomerular protein. Saturation and affinity cross-linking experiments confirmed the presence of two distinct receptor subtypes - the B-receptor (130 kDa) and the C-receptor (65 kDa). Quantitative differentiation of both ANF binding sites was achieved by competitive displacement with two different unlabeled ANF ligands: a) rANF(99-126) (homologous displacement), b) des(18-22)rANF(4-23)NH2(heterologous displacement). Intact glomeruli and glomerular membranes did not differ significantly in receptor density for the B-receptor (71 ± 37 vs. 94 ± 53 fmol/mg protein) or the C-receptor (976 ± 282 vs. 966 ± 167 fmol/mg protein) or in affinity constants for the B-receptor (43 ± 36 vs. 52 ± 44 pM) or the C-receptor (876 ± 377 vs. 307 ± 36 pM). Glomerular membranes compared to glomeruli showed less nonspecific binding and less intra-assay variation of measuring points done in triplicates. This method of selective displacement should allow to study the influence of various physiological and pathophysiological conditions on the binding properties of B-and C-receptors for ANF

Using Empirically Validated Reading Strategies to Improve Middle School Students\u27 Reading Fluency of classroom Textbooks

According to the National Center for Education Statistics (2007), 27% of the nation’s 8th grade population scored below the basic reading level in 2006-2007. Reading fluency strategies are a viable practice for improving reading achievement yet seldom are they incorporated into the 8th grade curriculum. To be effective, passages used in reading fluency strategies should be at the students’ instructional reading level (Daly, Persampieri, et al., 2005; Welsch, 2007). However, if increased oral reading fluency gained at the instructional reading level fails to generalize to content-area text that a student is required to read, the gain is not clinically significant, as it does not allow the student access to required reading. Stahl and Heubach (2006) recommended providing instruction in more difficult material while providing a strong degree of support. In this study, four middle school students reading one to two years below grade level received strong support for increasing reading fluency while using their social studies textbook. The intervention package consisted of listening passage preview, repeated reading, phrase-drill error correction, and performance feedback with student charting. Two research questions guided this study: (a) What are the effects of a comprehensive treatment package consisting of commonly utilized strategies for improving oral reading fluency on middle school students’ oral reading fluency using their required grade-level social studies textbooks? and (b) to what extent does performance generalize to required literature textbook passages and passages from CRCT Coach in Science (2002) and CRCT Coach in Social Studies (2002)? A multiple probe across participants design was used to answer these questions. Visual analysis of graphically displayed single-case data revealed that the multicomponent reading intervention positively affected student performance on intervention and generalization passages. The results of this study are promising, and given that reading content-area text is the core of education in middle school, further research is necessary

Knowledge tree: Putting discourse into computer‐based learning

Most CBL materials currently in use model only the declarative aspects of the learning process. If such courseware is used without careful planning, this can be dangerous because one of the most fundamental aspects of education is the dialogue that occurs between teachers and the students. Traditionally, this has taken place in informal discussions as well as in formal small‐group learning sessions such as the conventional tutorial. However, as the student‐staff ratio increases, so does the opportunity for this type of personal dialogue decrease. Modern networking technology offers a huge potential to add discourse to CBL, but there are many pedagogical problems involved with the intrinsically ephemeral and anarchic nature both of the Internet and of most conferencing or bulletin‐board systems. In this paper we describe a software system called Knowledge Tree (KT) which we have developed to address some of these issues. KT combines a hierarchical concept‐oriented database functionality with that of a Usenet‐style bulletin board Using this, a knowledge garden may be developed for any subject area. These each contain a hypermedia database of frequently asked questions, together with answers provided by subject experts. There is provision for inter‐student discussions of problems and issues. When students ask new questions these are automatically emailed to a relevant subject expert (determined by a subject‐specific concept thesaurus). The answer is then placed in the database which eventually grows to become a valuable teaching resource. KT is discipline‐independent as the concept thesaurus can be changed to encapsulate any domain of knowledge. We have used it in support of conventional lecture courses, as an important component of a multimedia course, and for general IT support. These examples illustrate the role that this system can play both in basic information provision, and in facilitating the discussion of deep issues

Barriers to pro-environmental behaviours at Bournemouth University

This study investigates the main barriers to pro-environmental behaviours at Bournemouth University (BU). The University is committed to help achieving the UN Sustainable Development Goals and over the years has implemented several activities to improve its sustainability performance covering aspects such as energy and carbon management, recycling, travelling, sustainable and ethical food, ethical purchasing and investment, education for sustainable development, and student and staff engagement in sustainability via the Green Impact scheme run by the National Union of Students (NUS). While most of the activities have been successful, participation to the Green Impact scheme, particularly of staff, has been slow. This research project investigates the main barriers at the university to more participation and engagement in environmental initiatives like the Green Impact. It compares cross-faculty behavioural habits and also investigates what the main barriers are to staff engaging further. The research takes a two-step approach, employing both quantitative and qualitative methods. The first part of the research includes a questionnaire and the second a semi-structured interview with staff at the University of Sheffield who is championing the Green Impact scheme. Surprisingly, results demonstrated that there was no significant difference in behaviours between faculties where staff participated to the Green Impact scheme and faculties where staff did not. Results also showed that the main barriers to pro-environmental behaviours were time, funding, and institutional hurdles, in line with other similar recent research in the field. The semi-structured interview with staff at the University of Sheffield helped in defining possible solutions for BU to increase Green Impact participation and ultimately staff engagement in achieving the Sustainable Development Goals

Nozzle flame holding characterization

Issued as final reportGeneral Electric Compan

Intense-Field Ionization of Monoaromatic Hydrocarbons using Radiation Pulses of Ultrashort Duration: Monohalobenzenes and Azabenzenes

Using 50-fs, 800-nm pulses, we study the intense-field ionization and fragmentation of the monohalobenzenes C_(6)H_(5)-X (X=F, Cl, Br, I) and of the heterocyclics azabenzene C5H5N (pyridine) and the three diazabenzenes C_(4)H_(4)N_(2) (pyridazine, pyrimidine, and pyrazine). Avoiding focal intensity averaging we find indications of resonance-enhanced MPI. In the monohalobenzenes the propensity for fragmentation increases for increasing Z: fluorobenzene yields predominantly C6H5Fn+, while iodobenzene yields atomic ions with charges up to I^(8+). We ascribe this to the heavy-atom effect: the large charge of the heavy halogens' nuclei induces ultrafast intersystem crossing to dissociative triplet states

Should nutrient profile models be ‘category specific' or ‘across-the-board'? A comparison of the two systems using diets of British adults

Background/Objectives: Nutrient profile models have the potential to help promote healthier diets. Some models treat all foods equally (across-the-board), some consider different categories of food separately (category specific). This paper assesses whether across-the-board or category-specific nutrient profile models are more appropriate tools for improving diets. Subjects/Methods: Adult respondents to a British dietary survey were split into four groups using a diet quality index. Fifteen food categories were identified. A nutrient profile model provided a measure of the healthiness of all foods consumed. The four diet quality groups were compared for differences in (a) the calories consumed from each food category and (b) the healthiness of foods consumed in each category. Evidence of a healthier diet quality groups consuming more of healthy food categories than unhealthy diet quality groups supported the adoption of across-the-board nutrient profile models. Evidence of healthier diet quality groups consuming healthier versions of foods within food categories supported adoption of category-specific nutrient profile models. Results: A significantly greater percentage of the healthiest diet quality group's diet consisted of fruit and vegetables (21 vs 16%), fish (3 vs 2%) and breakfast cereals (7 vs 2%), and significantly less meat and meat products (7 vs 14%) than the least healthy diet quality group. The foods from the meat, dairy and cereals categories consumed by the healthy diet quality groups were healthier versions than those consumed by the unhealthy diet quality groups. Conclusions: All other things being equal, nutrient profile models designed to promote an achievable healthy diet should be category specific but with a limited number of categories. However models which use large number of categories are unhelpful for promoting a healthy diet

Best practices for assessing ocean health inmultiple contexts using tailorable frameworks

Marine policy is increasingly calling for maintaining or restoring healthy oceans while human activities continue to intensify. Thus, successful prioritization and management of competing objectives requires a comprehensive assessment of the current state of the ocean. Unfortunately, assessment frameworks to define and quantify current ocean state are often site-specific, limited to a few ocean components, and difficult to reproduce in different geographies or even through time, limiting spatial or temporal comparisons as well as the potential for shared learning. Ideally, frameworks should be tailorable to accommodate use in disparate locations and contexts, removing the need to develop frameworks de novo and allowing efforts to focus on the assessments themselves to advise action. Here, we present some of our experiences using the Ocean Health Index (OHI) framework, a tailorable and repeatable approach that measures health of coupled human-ocean ecosystems in different contexts by accommodating differences in local environmental characteristics, cultural priorities, and information availability and quality. Since its development in 2012, eleven assessments using the OHI framework have been completed at global, national, and regional scales, four of which have been led by independent academic or government groups. We have found the following to be best practices for conducting assessments: Incorporate key characteristics and priorities into the assessment framework design before gathering information; Strategically define spatial boundaries to balance information availability and decision-making scales; Maintain the key characteristics and priorities of the assessment framework regardless of information limitations; and Document and share the assessment process, methods, and tools. These best practices are relevant to most ecosystem assessment processes, but also provide tangible guidance for assessments using the OHI framework. These recommendations also promote transparency around which decisions were made and why, reproducibility through access to detailed methods and computational code, repeatability via the ability to modify methods and computational code, and ease of communication to wide audiences, all of which are critical for any robust assessment process