Scintillation Light from Cosmic-Ray Muons in Liquid Argon

This paper reports the results of an experiment to directly measure the time-resolved scintillation signal from the passage of cosmic-ray muons through liquid argon. Scintillation light from these muons is of value to studies of weakly-interacting particles in neutrino experiments and dark matter searches. The experiment was carried out at the TallBo dewar facility at Fermilab using prototype light guide detectors and electronics developed for the Deep Underground Neutrino Experiment. Two models are presented for the time structure of the scintillation light, a phenomenological model and a composite model. Both models find $\tau_{\text{T}} = 1.52$ $\mu$s for the decay time constant of the Ar$_2^*$ triplet state. These models also show that the identification of the "early" light fraction in the phenomenological model, $F_{\text{E}}\approx 25\%$ of the signal, with the total light from singlet decays is an underestimate. The total fraction of singlet light is $F_{\text{S}} \approx 36\%$, where the increase over $F_{\text{E}}$ is from singlet light emitted by the wavelength shifter through processes with long decay constants. The models were further used to compute the experimental particle identification parameter $F_{\text{prompt}}$, the fraction of light coming in a short time window after the trigger compared with the light in the total recorded waveform. The models reproduce quite well the typical experimental value $\sim0.3$ found by dark matter and double $\beta$-decay experiments, which suggests this parameter provides a robust metric for discriminating electrons and muons from more heavily ionizing particles.Comment: 30 pages, 10 figures. This experiment has been repeated with improved data quality and analysis technique

Peer Mentors and Writing Center Tutors: What our collaborations taught us about serving the SJSU Freshmen Students

The Library Outpost, a satellite office of the campus’s Dr. Martin Luther King Jr. Library, seeks ways to reach out to First Year students who are new to writing research papers. One of our goals is to meet the First Year students on their own turf. Since the Peer Mentors and Writing Center tutors have peer relationships with the First year students, we want to learn how we can collaborate with them to provide services to the First year students. We surveyed the Peer Mentors and Writing Center Tutors to assess their perceptions of their own research skills, and their students’ research needs to guide the services and workshops offered by the Library Outpost

Productivity of Florida Springs: Second semi-annual report to the Biology Division, Office of Naval Research progress from February 1, 1953 to June 30, 1953

During this second six months emphasis has been laid on developing a complete understanding of the metabolism of the Silver Springs ecosystem as an example of a community apparently in a steady state. Variation in phosphates, uptake of nitrates, and importance of boron have been estimated. Fluctuation of some major elements has been estimated. Examination of stomach contents has permitted trophic classifications of dominant species and the standing crops have been estimated for these species by number and by dry weight. From these a pyramid of mass has been constructed. Special attention has been paid to bacteria using 3 methods for comparison of Silver Springs with lakes and estimation of the standing crop. The oxygen gradient method has been repeated at half hourly intervals. A carbon-dioxide gradient method has also been used to check the oxygen and to obtain a photosynthetic quotient. Black and light Bell jar experiments have been initiated to obtain checks on the other production measurement and to obtain a community respiration rate. An approximate balance has resulted from estimates of production , respiration , and downstream loss. A flow rate diagram has been constructed to clarify definitions of efficiency and their relationship to a steady state system. Mr. Sloan has statistically verified the increase of insect number and variety away from the boils and demonstrated the reliability of quantitative dipping for aquatic insects. Plans for the third half year include detained and comparative study of the dominant algae and further estimates of rates of growth of all community components. (29pp.

The contribution of fatigue and sleepiness to depression in patients attending the sleep laboratory for evaluation of obstructive sleep apnea

Purpose: A high prevalence of depressive symptomatology has been reported amongst sufferers of obstructive sleep apnea (OSA), but it remains unclear as to whether this is due to their OSA or other factors associated with the disorder. The current study aimed to assess the incidence and aetiology of depression in a community sample of individuals presenting to the sleep laboratory for diagnostic assessment of OSA. Methods: Forty-five consecutive individuals who presented to the sleep laboratory were recruited; of those, 34 were diagnosed with OSA, and 11 were primary snorers with no clinical or laboratory features of OSA. Nineteen control subjects were also recruited. Patients and controls completed the Beck Depression Inventory, the Profile of Mood States (POMS), and the Epworth Sleepiness Scale to assess their mood and sleepiness, prior to their polysomnography. Results: All patients reported significantly more depressive symptoms compared with healthy controls, regardless of their degree of OSA. There were no significant differences between OSA patients and primary snorers on any of the mood and self-rated sleepiness measures. Depression scores were not significantly associated with any of the nocturnal variables. Regression analysis revealed that the POMS fatigue subscale explained the majority of the variance in subjects' depression scores. Conclusions: Fatigue was the primary predictor of the level of depressive symptoms in patients who attended the sleep laboratory, regardless of the level of severity of sleep disordered breathing. When considering treatment options, practitioners should be aware of the concomitant occurrence of depressive symptoms and fatigue in patients presenting with sleep complaints, which may not be due to a sleep disorder

Serrated trailing edges for improving lift and drag characteristics of lifting surfaces

An improvement in the lift and drag characteristics of a lifting surface is achieved by attaching a serrated panel to the trailing edge of the lifting surface. The serrations may have a saw-tooth configuration, with a 60 degree included angle between adjacent serrations. The serrations may vary in shape and size over the span-wise length of the lifting surface, and may be positioned at fixed or adjustable deflections relative to the chord of the lifting surface

Productivity of Florida Springs: First annual (3rd semi-annual) report to Biology Branch, Office of Naval Research progress from January 1 to December 31, 1953

By means of new methods it has been possible to measure the overall community metabolism as well as the standing state community in Silver Springs. Photosynthetic rates have been determined by downstream gradient methods, transplantation growth plots, and bell jars diurnally and annually. Respiration rates have been estimated with bell jars. The downstream losses of particulate, and dissolved organic matter have been found to balance, the excess of photosynthesis over respiration. The community has thus been demonstrated to be in a constant temperature, steady state, somewhat comparable to a climax on land. Nitrate, phosphate, and major chemical constituents are essentially constant. There is an approximate constancy of standing crop of organisms although the production rates in summer are three times those in the winter. Some evidence suggests that there, are photoperiodic changes in reproduction rates in spite of constant temperature. Rates of protein syntehsis estimated from nitrate uptake downstream agree (1) with photosynthetic quotients obtained from carbon dioxide and oxygen uptake downstream and (2) with the nitrogen content of the community. The overall annual production of 50,000 lbs/acre is the greatest productivity we know of on land or sea. Such high figures seem reasonable with the flow of high nutrient, warm water and high light intensity over a dense periphyton community. Theoretical concepts of steady state thermodynamics have been applied to show that self maintaining open systems tend to adjust to high power and low efficiency output. The 3% photosynthetic efficiency observed in Silver Springs is in agreement with this principle. Pyramids of weight and pyramids of number have been determined including bacteria. These pyramids are similar to some in the literature. The contribution of an acre of a fertile stream annually is readily inferred from data obtained on downstream increase of bacteria, chlorophyll, and organic matter. In other springs, Mr. Sloan has related stability of insect populations to chlorinity and to gradients of stability of environmental factors. Dr. L.S. Whitford during the summer made an ecological and taxonomic study of the distribution of algae in 26 contrasting springs. From this lists and from analytical data on the chemostatic water in these springs one can infer culture conditions necessary for many species. (27 pages

Exoplanet Detection Techniques

We are still in the early days of exoplanet discovery. Astronomers are beginning to model the atmospheres and interiors of exoplanets and have developed a deeper understanding of processes of planet formation and evolution. However, we have yet to map out the full complexity of multi-planet architectures or to detect Earth analogues around nearby stars. Reaching these ambitious goals will require further improvements in instrumentation and new analysis tools. In this chapter, we provide an overview of five observational techniques that are currently employed in the detection of exoplanets: optical and IR Doppler measurements, transit photometry, direct imaging, microlensing, and astrometry. We provide a basic description of how each of these techniques works and discuss forefront developments that will result in new discoveries. We also highlight the observational limitations and synergies of each method and their connections to future space missions.Comment: 24 pages, 19 figures, PPVI proceedings. Appears as 2014, Protostars and Planets VI, Henrik Beuther, Ralf S. Klessen, Cornelis P. Dullemond, and Thomas Henning (eds.), University of Arizona Press, Tucson, 914 pp., p.715-73

Fundamentals Or Fancies? The Justification Of Returns To Equity From 1950 To 2007

Profit-maximizing firms should continue to invest in economic capital to the point where the marginal product of capital equals the marginal cost of financial capital.  As such, the returns to shareholders on the right-hand side of the balance sheet should be justified by the returns generated by assets employed on the left-hand side.  The author compares the net real after-tax marginal product of capital with returns on U.S. equities over the period 1950 to 2007.  The results show that long-term returns on large cap U.S. equities are justified by the marginal product of capital

Does The Mix Of A State?s Tax Portfolio Matter? An Empirical Analysis Of United States Tax Portfolios And The Relationship To Levels And Growth In Real Per Capita Gross State Product

An important part of the economic environment for any business is the tax climate. At the federal level, arguments are often made for abandoning the income tax in favor of a national sales tax or other type of tax. At the state level, the United States has a laboratory of sorts for examining the economic impact of various types of taxes. The states exhibit a wide degree of variation in the kinds and mix of taxes upon which they rely to raise revenue. This provides an opportunity for comparing economic well-being with the mix of taxes for the various states. This paper presents the results of an empirical study of the relationship between the relative economic well-being of a state and its relative portfolio of taxation. Data on the kinds and relative mix of taxes for the 50 United States for the years 1993-1999 are summarized. While the direction of causation is still an issue, the results of the study show that statistically significant relationships do exist between a state’s tax portfolio and its level and growth of real per capita gross state product. Hopefully this study will add to our understanding of the impact of taxation on the economic climate for business