Physics case of the very high energy electron--proton collider, VHEeP

The possibility of a very high energy electron-proton (VHEeP) collider with a centre-of-mass energy of 9 TeV has been presented at previous workshops. These proceedings briefly summarise the VHEeP concept, which was recently published, and developments since then, as well as future directions. At the VHEeP collider, with a centre-of-mass energy 30 times greater than HERA, parton momentum fractions, $x$, down to about $10^{-8}$ are accessible for photon virtualities, $Q^2$, of 1 GeV$^2$. This extension in the kinematic range to low $x$ complements proposals for other electron-proton or electron-ion colliders.Comment: 6 pages, 2 figures, for proceedings of DIS 2017 worksho

Promoting Medical Education at Cabot School

As a Cabot School alumni, I returned to Cabot School to talk to the students about opportunities in medicine. Cabot School is considered environmentally disadvantaged by the Agency of Education. By definition, the individual comes from an environment that has inhibited him/her from obtaining the knowledge, skill and abilities required to enroll in and graduate from an undergraduate or graduate school. The percentage of students achieving proficiency in math and reading/language arts is lower than the Vermont state average for the 2016-17 school year. The goal of this project was to share my journey to medical school with the Cabot students and introduce them to careers in medicine.https://scholarworks.uvm.edu/fmclerk/1588/thumbnail.jp

Landscape Analysis of Soil Methane Flux Across Complex Terrain

Relationships between methane (CH4) fluxes and environmental conditions have been extensively explored in saturated soils, while research has been less prevalent in aerated soils because of the relatively small magnitudes of CH4 fluxes that occur in dry soils. Our study builds on previous carbon cycle research at Tenderfoot Creek Experimental Forest, Montana, to identify how environmental conditions reflected by topographic metrics can be leveraged to estimate watershed scale CH4 fluxes from point scale measurements. Here, we measured soil CH4 concentrations and fluxes across a range of landscape positions (7 riparian, 25 upland), utilizing topographic and seasonal (29 May–12 September) gradients to examine the relationships between environmental variables, hydrologic dynamics, and CH4 emission and uptake. Riparian areas emitted small fluxes of CH4 throughout the study (median: 0.186 µg CH4–C m−2 h−1) and uplands increased in sink strength with dry-down of the watershed (median: −22.9 µg CH4–C m−2 h−1). Locations with volumetric water content (VWC) below 38 % were methane sinks, and uptake increased with decreasing VWC. Above 43 % VWC, net CH4 efflux occurred, and at intermediate VWC net fluxes were near zero. Riparian sites had near-neutral cumulative seasonal flux, and cumulative uptake of CH4 in the uplands was significantly related to topographic indices. These relationships were used to model the net seasonal CH4 flux of the upper Stringer Creek watershed (−1.75 kg CH4–C ha−1). This spatially distributed estimate was 111 % larger than that obtained by simply extrapolating the mean CH4 flux to the entire watershed area. Our results highlight the importance of quantifying the space–time variability of net CH4 fluxes as predicted by the frequency distribution of landscape positions when assessing watershed scale greenhouse gas balances

Public perceptions of drinking water: A postal survey of residents with private water supplies

Background: In Canada, the legal responsibility for the condition of private water supplies, including private wells and cisterns, rests with their owners. However, there are reports that Canadians test these water supplies intermittently and that treatment of such water is uncommon. An estimated 45% of all waterborne outbreaks in Canada involve non-municipal systems. An understanding of the perceptions and needs of Canadians served by private water supplies is essential, as it would enable public health professionals to better target public education and drinking water policy. The purpose of this study was to investigate the public perceptions of private water supplies in the City of Hamilton, Ontario (Canada), with the intent of informing public education and outreach strategies within the population. Methods: A cross-sectional postal survey of 246 residences with private water supplies was conducted in May 2004. Questions pertained to the perceptions of water quality and alternative water sources, water testing behaviours and the self-identified need for further information. Results: Private wells, cisterns or both, were the source of household water for 71%, 16% and 13% of respondents, respectively. Although respondents rated their water quality highly, 80% also had concerns with its safety. The most common concerns pertained to bacterial and chemical contamination of their water supply and its potential negative effect on health. Approximately 56% and 61% of respondents used in-home treatment devices and bottled water within their homes, respectively, mainly due to perceived improvements in the safety and aesthetic qualities compared to regular tap water. Testing of private water supplies was performed infrequently: 8% of respondents tested at a frequency that meets current provincial guidelines. Two-thirds of respondents wanted more information on various topics related to private water supplies. Flyers and newspapers were the two media reported most likely to be used. Conclusion: Although respondents rated their water quality highly, the majority had concerns regarding the water from their private supply, and the use of bottled water and water treatment devices was extensive. The results of this study suggest important lines of inquiry and provide support and input for public education programs, particularly those related to private water testing, in this population

Quantification of aortic valvuloplasty catheter size using a metrology system based on brightfield microscopy

Balloon aortic valvuloplasty (BAV) has been employed [1] as a simple and low-cost treatment method for patients with severe aortic stenosis, for symptom palliation in patients considered inoperable, for aortic valve replacement and to select the proper transcatheter heart valve (THV) size. During THV implantation choosing the correct balloon size is paramount for minimizing the risks of coronary occlusion, annular damage or THV embolization. Current methods for selecting the proper balloon dimensions are based on transesophageal echocardiography and computed tomography requiring trained staff for image interpretation, expensive equipment and high doses of patient radiation exposure. Alternative methods propose the use of BAV to determine the correct THV size before its implantation [2]. The strategy is based on determining the BAV aortic anulus using a sterile caliper. Any slight pressure to the balloon may compromise the measurement accuracy. In this paper, we present a non-contact metrology system for BAV measurement based on bright field microscopy (BFM). The balloons under test (MedTek-22 and TrueDilation-22) were clamped vertically, employing a tension spring to restrict movement and ensure perpendicularity to the microscope optical axis. The BFM is based on an Olympus PLN 4X WD~18.5mm, NA 0.1, a tube lens (f~180mm) and a FL3-U3- 13S2M-CS camera mounted on top of a custom-made linear stage having a coarse resolution of ~ 3.3µm. Balloon expansion was performed using a Boston scientific Encore 26 inflation device. The balloons are made up of an outer shell with an internal catheter tube (Ø~2mm). By focusing the microscope on the internal tube, then moving the linear stage to refocus on the balloon outer wall, the inner tube to outer wall dimension (see figure inset) can be accurately measured using the linear stage digital readout. The balloon was inflated up to six times recording the pressure and radius at each stage of inflation (twice the amount required for THV). Our non-contact method preserves the catheter sterile conditions and allows the accurate measurement of the BAV anulus showing: a) repeatability of the achieved balloon radius within all the inflation rounds, b) accurate measurements with a standard error of ±200 µm c) and a variation of 1.38 ±0.0387 mm from the manufacturer data. Knowing the exact balloon dimensions is crucial for avoiding the adverse consequences of THV oversizing. Our method may potentially improve the safety and efficacy of THV implantation

Transmittance and reflectance measurements at terahertz frequencies on a superconducting BaFe_{1.84}Co_{0.16}As_2 ultrathin film: an analysis of the optical gaps in the Co-doped BaFe_2As_2 pnictide

Here we report an optical investigation in the terahertz region of a 40 nm ultrathin BaFe$_{1.84}$Co$_{0.16}$As$_2$ superconducting film with superconducting transition temperature T$_c$ = 17.5 K. A detailed analysis of the combined reflectance and transmittance measurements showed that the optical properties of the superconducting system can be described in terms of a two-band, two-gap model. The zero temperature value of the large gap $\Delta_B$, which seems to follow a BCS-like behavior, results to be $\Delta_B$(0) = 17 cm$^{-1}$. For the small gap, for which $\Delta_A$(0) = 8 cm$^{-1}$, the temperature dependence cannot be clearly established. These gap values and those reported in the literature for the BaFe$_{2-x}$Co$_{x}$As$_2$ system by using infrared spectroscopy, when put together as a function of T$_c$, show a tendency to cluster along two main curves, providing a unified perspective of the measured optical gaps. Below a temperature around 20 K, the gap-sizes as a function of T$_c$ seem to have a BCS-like linear behavior, but with different slopes. Above this temperature, both gaps show different supra-linear behaviors