Neutronics Simulations of Graphite Experiments

A widely used method for Neutronics simulations is MCNP6. Throughout this work, multiple MCNP6 simulations were completed on different supercomputers. These simulations entailed realistic representations of experiments being completed. The IM1 configuration was simulated with the corrected source definition. This geometry resulted in 0.222 as the graphite to air ratio. The IM1 experiment required many different configurations to be modeled in MCNP6. In order to further characterize the experiment different boric acid concentrations were poured in a beaker. The boric acid concentration produced an exponential fit, this represented the decrease in absorptions per second as the boric acid concentration was increased. With the progression of the project a more complex problem was created. This year 5 geometry was approached primarily through a straightforward stacked air duct problem. These results concluded that with the addition of a more complex geometry MCNP6 would require many neutron particle histories and become computationally expensive. Finally, in anticipation of the arrival of the neutron generator safety calculations were completed. These calculations yielded an estimated dose of 107.04 ± 0.3 mrem per hour in the entrance way during operation. The estimated dose was less than 5 mrem per hour in every other location of concern. The geometries were developed in MCNP6 and converted into PDT readable formats. This work was completed in order to aid in the validation of PDT development

Criminal Law - Murder - Evidence - Psychiatric Testimony - Specific Intent - Diminished Capacity

The Supreme Court of Pennsylvania has held that a psychiatrist\u27s expert testimony is relevant in a prosecution for first degree murder when the testimony is offered to demonstrate that the defendant lacked sufficient mental capacity to formulate the specific intent required for a conviction of first degree murder. Commonwealth v. Walzack, 468 Pa. 210, 360 A.2d 914 (1976)

An Autoignition Study of iso-Butanol: Experiments and Modeling

The autoignition delays of iso-butanol, oxygen, and nitrogen mixtures have been measured in a heated rapid compression machine (RCM). At compressed pressures of 15 and 30 bar, over the temperature range 800-950 K, and for equivalence ratio of $\phi$ = 0.5 in air, no evidence of an NTC region of overall ignition delay is found. By comparing the data from this study taken at $\phi$ = 0.5 to previous data collected at $\phi$ = 1.0 (Weber et al. 2013), it was found that the $\phi$ = 0.5 mixture was less reactive (as measured by the inverse of the ignition delay) than the $\phi$ = 1.0 mixture for the same compressed pressure. Furthermore, a recent chemical kinetic model of iso-butanol combustion was updated using the automated software Reaction Mechanism Generator (RMG) to include low- temperature chain branching pathways. Comparison of the ignition delays with the updated model showed reasonable agreement for most of the experimental conditions. Nevertheless, further work is needed to fully understand the low temperature pathways that control iso-butanol autoignition in the RCM.Comment: 6 pages, 4 figures, 8th US National Combustion Meetin

Rate of photosynthetic induction in fluctuating light varies widely among genotypes of wheat.

Crop photosynthesis and yield are limited by slow photosynthetic induction in sunflecks. We quantified variation in induction kinetics across diverse genotypes of wheat for the first time. Following a preliminary study that hinted at wide variation in induction kinetics across 58 genotypes, we grew 10 genotypes with contrasting responses in a controlled environment and quantified induction kinetics of carboxylation capacity (Vcmax) from dynamic A versus ci curves after a shift from low to high light (from 50 µmol m-2 s-1 to 1500 µmol m-2 s-1), in five flag leaves per genotype. Within-genotype median time for 95% induction (t95) of Vcmax varied 1.8-fold, from 5.2 min to 9.5 min. Our simulations suggest that non-instantaneous induction reduces daily net carbon gain by up to 15%, and that breeding to speed up Vcmax induction in the slowest of our 10 genotypes to match that in the fastest genotype could increase daily net carbon gain by up to 3.4%, particularly for leaves in mid-canopy positions (cumulative leaf area index ≤1.5 m2 m-2), those that experience predominantly short-duration sunflecks, and those with high photosynthetic capacities

Non-Ossicular Signal Transmission in Human Middle Ears: Experimental Assessment of the Acoustic Route with Perforated Tympanic Membranes

Direct acoustic stimulation of the cochlea by the sound-pressure difference between the oval and round windows (called the acoustic route ) has been thought to contribute to hearing in some pathological conditions, along with the normally dominant ossicular route. To determine the efficacy of this acoustic route and its constituent mechanisms in human ears, sound pressures were measured at three locations in cadaveric temporal bones [with intact and perforated tympanic membranes (TMs)]: (1) in the external ear canal lateral to the TM, PTM; (2) in the tympanic cavity lateral to the oval window, POW; and (3) near the round window, PRW. Sound transmission via the acoustic route is described by two concatenated processes: (1) coupling of sound pressure from ear canal to middle-ear cavity, H PCAV ≡ PCAV PTM, where PCAV represents the middle-ear cavity pressure, and (2) sound-pressure difference between the windows, HWPD ≡ (POW - PRW) PCAV. Results show that: H PCAV depends on perforation size but not perforation location; HWPD depends on neither perforation size nor location. The results (1) provide a description of the window pressures based on measurements, (2) refute the common otological view that TM perforation location affects the relative phase of the pressures at the oval and round windows, and (3) show with an intact ossicular chain that acoustic-route transmission is substantially below ossicular-route transmission except for low frequencies with large perforations. Thus, hearing loss from TM perforations results primarily from reduction in sound coupling via the ossicular route. Some features of the frequency dependence of H PCAV and HWPD can be interpreted in terms of a structure-based lumped-element acoustic model of the perforation and middle-ear cavities

Takotsubo Cardiomyopathy: A Case Series and Review of the Literature

Takotsubo cardiomyopathy (TCM) is an unusual form of acute cardiomyopathy showing left ventricular apical ballooning. It is often triggered by intense physical or emotional distress. We report here four cases of TCM and a review of the literature on the topic

Text messaging and brief phone calls for weight loss in overweight and obese English- and Spanish-speaking adults: A 1-year, parallel-group, randomized controlled trial.

BACKGROUND:Weight loss interventions based solely on text messaging (short message service [SMS]) have been shown to be modestly effective for short periods of time and in some populations, but limited evidence is available for positive longer-term outcomes and for efficacy in Hispanic populations. Also, little is known about the comparative efficacy of weight loss interventions that use SMS coupled with brief, technology-mediated contact with health coaches, an important issue when considering the scalability and cost of interventions. We examined the efficacy of a 1-year intervention designed to reduce weight among overweight and obese English- and Spanish-speaking adults via SMS alone (ConTxt) or in combination with brief, monthly health-coaching calls. ConTxt offered 2-4 SMS/day that were personalized, tailored, and interactive. Content was theory- and evidence-based and focused on reducing energy intake and increasing energy expenditure. Monthly health-coaching calls (5-10 minutes' duration) focused on goal-setting, identifying barriers to achieving goals, and self-monitoring. METHODS AND FINDINGS:English- and Spanish-speaking adults were recruited from October 2011 to March 2013. A total of 298 overweight (body mass index [BMI] 27.0 to 39.9 kg/m2) adults (aged 21-60 years; 77% female; 41% Hispanic; 21% primarily Spanish speaking; 44% college graduates or higher; 22% unemployed) were randomly assigned (1:1) to receive either ConTxt only (n = 101), ConTxt plus health-coaching calls (n = 96), or standard print materials on weight reduction (control group, n = 101). We used computer-based permuted-block randomization with block sizes of three or six, stratified by sex and Spanish-speaking status. Participants, study staff, and investigators were masked until the intervention was assigned. The primary outcome was objectively measured percent of weight loss from baseline at 12 months. Differences between groups were evaluated using linear mixed-effects regression within an intention-to-treat framework. A total of 261 (87.2%) and 253 (84.9%) participants completed 6- and 12-month visits, respectively. Loss to follow-up did not differ by study group. Mean (95% confidence intervals [CIs]) percent weight loss at 12 months was -0.61 (-1.99 to 0.77) in the control group, -1.68 (-3.08 to -0.27) in ConTxt only, and -3.63 (-5.05 to -2.81) in ConTxt plus health-coaching calls. At 12 months, mean (95% CI) percent weight loss, adjusted for baseline BMI, was significantly different between ConTxt plus health-coaching calls and the control group (-3.0 [-4.99 to -1.04], p = 0.003) but not between the ConTxt-only and the control group (-1.07 [-3.05 to 0.92], p = 0.291). Differences between ConTxt plus health-coaching calls and ConTxt only were not significant (-1.95 [-3.96 to 0.06], p = 0.057). These findings were consistent across other weight-related secondary outcomes, including changes in absolute weight, BMI, and percent body fat at 12 months. Exploratory subgroup analyses suggested that Spanish speakers responded more favorably to ConTxt plus health-coaching calls than English speakers (Spanish contrast: -7.90 [-11.94 to -3.86], p < 0.001; English contrast: -1.82 [-4.03 to 0.39], p = 0.107). Limitations include the unblinded delivery of the intervention and recruitment of a predominantly female sample from a single site. CONCLUSIONS:A 1-year intervention that delivered theory- and evidence-based weight loss content via daily personalized, tailored, and interactive SMS was most effective when combined with brief, monthly phone calls. TRIAL REGISTRATION:ClinicalTrials.gov NCT01171586

Association Between Appendectomy and Clostridium difficile Infection

BackgroundRecent theory proposes that the appendix functions as a reservoir for commensal bacteria, and serves to re-inoculate the colon with normal flora in the event of pathogen exposure or purging of intestinal flora. If true, we reasoned that flora from a normal appendix could provide protection against Clostridium difficile. We conducted this investigation to examine the protective effect of an intact appendix and test the hypothesis that prior appendectomy will be more common among patients with a positive test for C. difficile as compared with patients who test negative.MethodsWe contacted patients who had undergone C. difficile testing and asked them whether or not they had a prior appendectomy. Using their responses and results from Toxin A & B EIA tests, we calculated the difference in appendectomy rates between those who tested positive for C. difficile, and those who tested negative. We considered a positive 15% absolute difference to represent a significant increase in appendectomy rate.ResultsWe enrolled 257 patients. Among the 136 who tested positive for C. difficile, 27 (19.9%) had prior appendectomies, while among 121 patients testing negative for C. difficile, 38 (31.4%) had prior appendectomies, yielding a difference in appendectomy rates of -11.6% (95% Confidence Interval: -21.6% to -0.9%).ConclusionsThe rate of prior appendectomy was actually lower among patients with a positive C. difficile test as compared to those with a negative test. Conversely, patients who tested positive for C. difficile were more likely to have an intact appendix than those who tested negative. These results suggest that rather than being protective, an intact appendix appears to promote C. difficile acquisition, carriage, and disease.KeywordsClostridium difficile; Appendix; Appendectomy; Microbial reservoir; Infection