Elucidating the Influence of the Activation Energy on Reaction Rates by Simulations Based on a Simple Particle Model

An application for visualizing the dynamic properties of an equimolar binary mixture of isotropic reactive particles is presented. By introducing a user selectable choice for the activation energy, the application is useful to demonstrate qualitatively that the reaction rate depends on the above choice and on temperature. The application is based on a 2D realistic dynamic model where atoms move because of their thermal energies and the trajectories are determined by solving numerically Newton’s laws according to a Molecular Dynamics (MD) scheme. Collisions are monitored as time progresses, and every time the collision energy is larger than the selected activation energy, a reactive event occurs. By examining the time evolution of the configurations, it is possible to observe that the number of reactive collisions is always smaller than the total number of collisions. However, the number of reactive events increases on raising the temperature and/or by decreasing the activation energy. The above observations, as well as more quantitative analyses of the simulation data, are useful in elucidating the connections existing among particle kinetic energy, temperature, and activation energy of the reaction. The application can be used at different levels of detail and in different instruction levels. Qualitative visual observations of the progress of the reaction are suitable at all levels of instruction. Systematic investigations on the effect of changes of temperature and activation energy, suitable for senior high school and college courses and useful to gain insight into kinetic models and Arrhenius’ law, are also reported

Rotational Feshbach Resonances in Ultracold Molecular Collisions

In collisions at ultralow temperatures, molecules will possess Feshbach resonances, foreign to ultracold atoms, whose virtual excited states consist of rotations of the molecules. We estimate the mean spacing and mean widths of these resonant states, exploiting the fact the molecular collisions at low energy display chaotic motion. As examples, we consider the experimentally relevant molecules O_2, OH, and PbO. The density of s-wave resonant states for these species is quite high, implying that a large number of narrow resonant states will exist.Comment: 4 pages, 2 figure

Improving public services through open data: public toilets

Bichard’s work for the TACT3 project (Bichard REF Output 3) found that UK toilet provision is not centrally collated and no national map or database of toilets exists. In contrast, the UK government’s white paper Open Public Services (2011) emphasised its commitment to incorporating the use of Open Data in public services provision that could be tailored to community preferences, and therefore be more sustainable. Incorporating Open Data on public toilet provision, Bichard and Knight (RCA) developed The Great British Public Toilet Map (GBPTM). Whilst a number of other websites and applications map toilets by ‘crowd surfing’, GBPTM is entirely populated by Open Data, and not only uses the data as information for users, but informs members of the public that such information is available and accessible for their use. This paper presents the development of the GBPTM, including inclusive design research and studies that compare accuracy of information directly provided by users with Open Data collected by local authorities. It suggests that, to meet the health and well-being of an ageing population, a sustainable and cost-effective solution must be found for ‘publicly accessible’ toilet provision, including opening up provision beyond that ‘for customers only’ and providing accurate information on current public provision. The paper highlights the barriers encountered in the production of Open Data by local authorities. A review of the paper in the journal Civil Engineering (May 2013) described the design of the GBPTM as a ‘simple and elegant solution’. The development of a digital output and an understanding of digitally based research led to Bichard’s successful submission to an EPSRC Digital Economy sandpit, in which she developed an interdisciplinary project with the Universities of Newcastle, Bournemouth and the West of England. The project, Family Rituals 2.0, secured £750,000 in research funding with Bichard as co-investigator (2013–15)

Cardiovascular-renal axis disorders in the domestic dog and cat: a veterinary consensus statement

OBJECTIVES There is a growing understanding of the complexity of interplay between renal and cardiovascular systems in both health and disease. The medical profession has adopted the term "cardiorenal syndrome" (CRS) to describe the pathophysiological relationship between the kidney and heart in disease. CRS has yet to be formally defined and described by the veterinary profession and its existence and importance in dogs and cats warrant investigation. The CRS Consensus Group, comprising nine veterinary cardiologists and seven nephrologists from Europe and North America, sought to achieve consensus around the definition, pathophysiology, diagnosis and management of dogs and cats with "cardiovascular-renal disorders" (CvRD). To this end, the Delphi formal methodology for defining/building consensus and defining guidelines was utilised. METHODS Following a literature review, 13 candidate statements regarding CvRD in dogs and cats were tested for consensus, using a modified Delphi method. As a new area of interest, well-designed studies, specific to CRS/CvRD, are lacking, particularly in dogs and cats. Hence, while scientific justification of all the recommendations was sought and used when available, recommendations were largely reliant on theory, expert opinion, small clinical studies and extrapolation from data derived from other species. RESULTS Of the 13 statements, 11 achieved consensus and 2 did not. The modified Delphi approach worked well to achieve consensus in an objective manner and to develop initial guidelines for CvRD. DISCUSSION The resultant manuscript describes consensus statements for the definition, classification, diagnosis and management strategies for veterinary patients with CvRD, with an emphasis on the pathological interplay between the two organ systems. By formulating consensus statements regarding CvRD in veterinary medicine, the authors hope to stimulate interest in and advancement of the understanding and management of CvRD in dogs and cats. The use of a formalised method for consensus and guideline development should be considered for other topics in veterinary medicine

Sex, But Not Spontaneous Cardiovagal Baroreflex Sensitivity, Predicts Tolerance To Simulated Hemorrhage

Some, but not all studies, suggest that spontaneous cardiovagal baroreflex sensitivity (cBRS; i.e., autonomic control of heart rate) is lower in females. However, it is unknown whether cBRS values are associated with hemorrhagic tolerance, which has repeatedly been demonstrated to be lower in females. PURPOSE: Therefore, the purpose of this study was to test the hypothesis that resting spontaneous cBRS is lower in females and that cBRS is associated with differences in hemorrhagic tolerance between the sexes. METHODS: 25 females (age: 26 ± 6 years) and 27 males (age: 30 ± 5 years) completed a progressive lower-body negative pressure (LBNP – a simulation of hemorrhage) protocol starting at -40 mmHg, which was reduced by 10 mmHg every 3 minutes until presyncope. Presyncope was defined by the subject feeling faint and/or nauseous; a rapid decline in blood pressure (BP) \u3c systolic BP of 80 mmHg; and/or a relative bradycardia accompanied by narrowing of pulse pressure. LBNP tolerance was quantified as cumulative stress index (CSI; mmHg*min). Heart rate (HR) and beat-to-beat BP (finometer) were measured continuously. Spontaneous cBRS was analyzed using the sequence method (i.e., ≥ 3 consecutive cardiac cycles of concordant changes in R-R interval and systolic BP, r2 ≥ 0.8 for such sequences). Data were compared between sexes using a Mann-Whitney U test. A least squares multiple linear regression was used to compare the effect of sex and cBRS on CSI. Data are presented as median ± IQR. RESULTS: Resting BP and HR were not different between the sexes (p \u3e 0.36 for both). Resting cBRS was not different between females and males (21 ± 16 vs. 22 ± 11 ms/mmHg, respectively, p = 0.73). As expected, females had a lower tolerance to LBNP (Females: 385 ± 322, Males: 918 ± 418 mmHg*min, p \u3c 0.0001). Multiple linear regression analysis revealed a significant effect of sex (β = 408, p= 0.04), but not resting cBRS (β = 2.4, p = 0.69) or sex*cBRS (i.e., interaction; β = 1.32, p = 0.87), on CSI. When data from both sexes were combined, there was no correlation between resting cBRS and CSI (r = 0.05, p = 0.71). CONCLUSION: Our cohort did not exhibit sex-related differences in resting cBRS. As expected, females had a lower tolerance to simulated hemorrhage. Importantly, we demonstrated that resting cBRS does not explain the observed sex differences in hemorrhagic tolerance

Short Report: Care Delivery The Ipswich Touch Test: a simple and novel method to screen patients with diabetes at home for increased risk of foot ulceration

Abstract Aims The Ipswich Touch Test is a novel method to detect subjects with diabetes with loss of foot sensation and is simple, safe, quick, and easy to perform and teach. This study determines whether it can be used by relatives and/or carers to detect reduced foot sensation in the setting of the patient's home. Methods The test involves lightly and briefly (1-2 s) touching the tips of the first, third and fifth toes of both feet with the index finger. Reduced foot sensation was defined as ≥ 2 insensate areas. Patients due to attend clinic over a 4-week period were invited by post. The invitation contained detailed instructions and a sheet for recording the results. The findings were compared with those obtained in clinic using the 10-g monofilament at the same six sites. Results Of 331 patients (174 males), 25.1% (n = 83) had ≥ 2 insensate areas to 10-g monofilament testing. Compared with this, the Ipswich Touch Test at home had a sensitivity of 78.3% and a specificity of 93.9%. The predictive values of detecting 'at-risk' feet were positive at 81.2% and negative at 92.8%. The likelihood ratios were positive at 12.9 and negative at 0.23. Conclusions With clearly written instructions, this simple test can be used by non-professionals to accurately assess for loss of protective sensation. We believe that the Ipswich Touch Test may also be a useful educational adjunct to improve awareness of diabetes foot disease in patients and relatives alike and empower them to seek appropriate care if sensation was found to be abnormal

Study of Small-Scale Anisotropy of Ultrahigh Energy Cosmic Rays Observed in Stereo by HiRes

The High Resolution Fly's Eye (HiRes) experiment is an air fluorescence detector which, operating in stereo mode, has a typical angular resolution of 0.6 degrees and is sensitive to cosmic rays with energies above 10^18 eV. HiRes is thus an excellent instrument for the study of the arrival directions of ultrahigh energy cosmic rays. We present the results of a search for anisotropies in the distribution of arrival directions on small scales (<5 degrees) and at the highest energies (>10^19 eV). The search is based on data recorded between 1999 December and 2004 January, with a total of 271 events above 10^19 eV. No small-scale anisotropy is found, and the strongest clustering found in the HiRes stereo data is consistent at the 52% level with the null hypothesis of isotropically distributed arrival directions.Comment: 4 pages, 3 figures. Matches accepted ApJL versio

Could humans recognize odor by phonon assisted tunneling?

Our sense of smell relies on sensitive, selective atomic-scale processes that are initiated when a scent molecule meets specific receptors in the nose. However, the physical mechanisms of detection are not clear. While odorant shape and size are important, experiment indicates these are insufficient. One novel proposal suggests inelastic electron tunneling from a donor to an acceptor mediated by the odorant actuates a receptor, and provides critical discrimination. We test the physical viability of this mechanism using a simple but general model. Using values of key parameters in line with those for other biomolecular systems, we find the proposed mechanism is consistent both with the underlying physics and with observed features of smell, provided the receptor has certain general properties. This mechanism suggests a distinct paradigm for selective molecular interactions at receptors (the swipe card model): recognition and actuation involve size and shape, but also exploit other processes.Comment: 10 pages, 1 figur