6,228 research outputs found
Living Through Rat Hell: The Lives and Escape Attempts of Soldiers at Libby Prison
This paper examines the lives and experiences of the men who survived the horrors of the Confederate prisoner of war camp, Libby Prison. Located inside the Confederacyâs capital city, the camp housed captured Union officers from its establishment in 1862 until the fall of Richmond in 1865. Under the command of the Major Thomas Turner and the dreaded Warden Richard Turner, Libby foreshadowed the horrors of concentration camps which would be run by other Germans eighty years later. Unlike a normal officerâs prison, the conditions faced by the officers at Libby were incredibly deplorable. By the warâs end, the camp became synonymous with the death, disease, and despair experienced by those who were held within its walls. Overall, this paper serves to recognize the legacy of the men who survived incarceration at Libby. Rather than being remembered solely for its harrowing conditions, Libby should also be recalled as a stirring example of the resiliency of American soldiers who are willing to fight for the defense of their country
The WiggleZ Dark Energy Survey: constraining the evolution of Newton's constant using the growth rate of structure
We constrain the evolution of Newton's constant using the growth rate of
large-scale structure measured by the WiggleZ Dark Energy Survey in the
redshift range . We use this data in two ways. Firstly we
constrain the matter density of the Universe, \omms (assuming General
Relativity), and use this to construct a diagnostic to detect the presence of
an evolving Newton's constant. Secondly we directly measure the evolution of
Newton's constant, \Geff, that appears in Modified Gravity theories, without
assuming General Relativity to be true. The novelty of these approaches are
that, contrary to other methods, they do not require knowledge of the expansion
history of the Universe, , making them model independent tests. Our
constraints for the second derivative of Newton's constant at the present day,
assuming it is slowly evolving as suggested by Big Bang Nucleosynthesis
constraints, using the WiggleZ data is \ddotGeff(t_0)=-1.19\pm 0.95\cdot
10^{-20}h^2 \textrm{yr}^{-2}, where is defined via , while using both the WiggleZ and the Sloan Digital Sky Survey
Luminous Red Galaxy (SDSS LRG) data is \ddotGeff(t_0)=-3.6\pm 6.8\cdot
10^{-21}h^2 \rm{yr}^{-2}, both being consistent with General Relativity.
Finally, our constraint for the rms mass fluctuation using the
WiggleZ data is , while using both the WiggleZ and the
SDSS LRG data , both in good agreement with the latest
measurements from the Cosmic Microwave Background radiation.Comment: 15 pages, 5 figures, 4 tables, changes match the published versio
Early Home Visits by a Registered Nurse Care Manager with Heart Failure Patients
Strategies focused on 30 days in the life of a patient with heart failure will have limited impact on the burden that heart failure will have nationally or individually. The broader landscape of readmission risk underscores the need for a more comprehensive approach to heart failure management. Care management with a registered nurse demonstrated efficiently coordinate care. Home visits address the peaks of risk in the post-discharge transition and palliative phase while providing longitudinal support. The purpose of this study is to substantiate that early home visits and telephone followup with a registered nurse after discharge from the hospital will decrease the readmission rates of heart failure patients. The interventions used were face-to-face encounters, follow up telephone phone calls, a quality of life self-report tool and a medication reconciliation tool. This study utilized a secondary analysis of data collected with a state-funded grant to decrease readmissions of heart failure patients at a local 700-bed, not-for-profit hospital. The participants were identified based on their lack of insurance or being underinsured with Medicaid. A newly dedicated heart failure unit with 10 dedicated beds was opened in 2011. A team of case managers, nurses, and physicians responsible for referring the patients who met certain guidelines were referred to the care manager. If the patient met the insurance criteria and was NYHF Class III or IV, the patient would then be eligible for a care manager and pharmacist to assist with the transition home. Study results concluded that there were definite advantages to both these services in decreasing readmissions
Formaldehyde over the central Pacific during PEM-Tropics B
Formaldehyde, CH2O, mixing ratios are reported for the central Pacific troposphere from a series of 41 flights, which took place in March-April 1999 as part of the NASA Pacific Exploratory Mission (PEM) -Tropics B mission. Ambient CH2O was collected in aqueous media and quantified using an enzyme-derivatization fluorescence technique. Primary calibration was performed using aqueous standards and known flow rates. Occasionally, CH2O gas standard additions to ambient air were performed as a secondary calibration. Analytical blanks were determined by replacing ambient air with pure air. The estimated precision was ±30 pptv and the estimated accuracy was the sum of ±30 parts per trillion by volume (pptv) ±15% of the measured value. Approximately 25% of the observations were less than the instrumental detection limit of 50 pptv, and 85% of these occurred above 6 km. CH2O mixing ratios decreased with altitude; for example, near the equator the median value in the lowest 2 km was 275 pptv, decreased to 150 pptv by 6 km and was below 100 pptv above 8 km. Between 130 and 170 W and below 1km, a small variation of CH2O mixing ratio with latitude was noted as near-surface median mixing ratios decreased near the equator (275 pptv) and were greater on either side (375 pptv). A marked decrease in near-surface CH2O (200 pptv) was noted south of 23° S on two flights. Between 3° and 23° S, median CH2O mixing ratios were lower in the eastern tropical Pacific than in the western or central Pacific; nominal differences were >100 pptv near the surface to âŒ100 pptv at midaltitude to âŒ50 pptv at high altitude. Off the coast of Central America and Mexico, mixing ratios as high as 1200 pptv were observed in plumes that originated to the east over land. CH2O observations were consistently higher than the results from a point model constrained by other photochemical species and meteorological parameters. Regardless of latitude or longitude, agreement was best at altitudes above 4 km where the difference between measured and modeled CH2O medians was less than 50 pptv. Below 2 km the model median was approximately 150 pptv less than the measured median. Copyright 2001 by the American Geophysical Union
A mass-balance/photochemical assessment of DMS sea-to-air flux as inferred from NASA GTE PEM-West a and B observations
This study reports dimethyl sulfide (DMS) sea-to-air fluxes derived from a mass-balance/photochemical-modeling approach. The region investigated was the western North Pacific covering the latitude range of 0°-30°N. Two NASA airborne databases were used in this study: PEM-West A in September-October 1991 and PEM-West B in February-March 1994. A total of 35 boundary layer (BL) sampling runs were recorded between the two programs. However, after filtering these data for pollution impacts and DMS lifetime considerations, this total was reduced to 13. Input for each analysis consisted of atmospheric DMS measurements, the equivalent mixing depth (EMD) for DMS, and model estimated values for OH and NO3. The evaluation of the EMD took into account both DMS within the BL as well as that transported into the overlying atmospheric buffer layer (BuL). DMS fluxes ranged from 0.6 to 3.0 Όmol m-2d-1 for PEM-West A (10 sample runs) and 1.4 to 1.9 Όmol m-2d-1 for PEM-West B (3 sample runs). Sensitivity analyses showed that the photochemically evaluated DMS flux was most influenced by the DMS vertical profile and the diel profile for OH. A propagation of error analysis revealed that the uncertainty associated with individual flux determinations ranged from a factor of 1.3 to 1.5. Also assessed were potential systematic errors. The first of these relates to our noninclusion of large-scale mean vertical motion as it might appear in the form of atmospheric subsidence or as a convergence. Our estimates here would place this error in the range of O to 30%. By far the largest systematic error is that associated with stochastic events (e.g., those involving major changes in cloud coverage). In the latter case, sensitivity tests suggested that the error could be as high as a factor of 2. With improvements in such areas as BL sampling time, direct observations of OH, improved DMS vertical profiling, direct assessment of vertical velocity in the field, and preflight (24 hours) detailed meteorological data, it appears that the uncertainty in this approach could be reduced to ±25%. Copyright 1999 by the American Geophysical Union
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Abundances and variability of tropospheric volatile organic compounds at the South Pole and other Antarctic locations
Multiyear (2000-2006) seasonal measurements of carbon monoxide, hydrocarbons, halogenated species, dimethyl sulfide, carbonyl sulfide and C1-C4 alkyl nitrates at the South Pole are presented for the first time. At the South Pole, short-lived species (such as the alkenes) typically were not observed above their limits of detection because of long transit times from source regions. Peak mixing ratios of the longer lived species with anthropogenic sources were measured in late winter (August and September) with decreasing mixing ratios throughout the spring. In comparison, compounds with a strong oceanic source, such as bromoform and methyl iodide, had peak mixing ratios earlier in the winter (June and July) because of decreased oceanic production during the winter months. Dimethyl sulfide (DMS), which is also oceanically emitted but has a short lifetime, was rarely measured above 5 pptv. This is in contrast to high DMS mixing ratios at coastal locations and shows the importance of photochemical removal during transport to the pole. Alkyl nitrate mixing ratios peaked during April and then decreased throughout the winter. The dominant source of the alkyl nitrates in the region is believed to be oceanic emissions rather than photochemical production due to low alkane levels.Sampling of other tropospheric environments via a Twin Otter aircraft included the west coast of the Ross Sea and large stretches of the Antarctic Plateau. In the coastal atmosphere, a vertical gradient was found with the highest mixing ratios of marine emitted compounds at low altitudes. Conversely, for anthropogenically produced species the highest mixing ratios were measured at the highest altitudes, suggesting long-range transport to the continent. Flights flown through the plume of Mount Erebus, an active volcano, revealed that both carbon monoxide and carbonyl sulfide are emitted with an OCS/CO molar ratio of 3.3 à 10-3 consistent with direct observations by other investigators within the crater rim. © 2010
Airborne sampling of aerosol particles: Comparison between surface sampling at Christmas Island and P-3 sampling during PEM-Tropics B
Bulk aerosol sampling of soluble ionic compounds from the NASA Wallops Island P-3 aircraft and a tower on Christmas Island during PEM-Tropics B provides an opportunity to assess the magnitude of particle losses in the University of New Hampshire airborne bulk aerosol sampling system. We find that most aerosol-associated ions decrease strongly with height above the sea surface, making direct comparisons between mixing ratios at 30 m on the tower and the lowest flight level of the P-3 (150 m) open to interpretation. Theoretical considerations suggest that vertical gradients of sea-salt aerosol particles should show exponential decreases with height. Observed gradients of Na+ and Mg2+, combining the tower observations with P-3 samples collected below 1 km, are well described by exponential decreases (r values of 0.88 and 0.87, respectively), though the curve fit underestimates average mixing ratios at the surface by 25%. Cascade impactor samples collected on the tower show that \u3e99% of the Na+ and Mg2+mass is on supermicron particles, 65% is in the 1â6 micron range, and just 20% resides on particles with diameters larger than 9 microns. These results indicate that our airborne aerosol sampling probes must be passing particles up to at least 6 microns with high efficiency. We also observed that nss SO42â and NH4+, which are dominantly on accumulation mode particles, tended to decrease between 150 and 1000 m, but they were often considerably higher at the lowest P-3 sampling altitudes than at the tower. This finding is presently not well understood
Useful Lessons from My Career as an Academic in Information Systems
This âlast lectureâ is to my fellow academics in information systems. My career spans the entire period of the adoption of information technology in organizations (from punched cards to the internet), the rise of the organization function of information systems, and the emergence of an academic field of IS (also called Management information Systems or MS). have had great opportunities to work with colleagues to: found an MS department, head an MS research center, create new S degrees and curricula, and write original books and manuals. I have been very involved with the Minnesota MS doctoral program as advisor to many doctoral students and on many dissertation committees. have been involved internationally and have been part of the leadership for our major S organizations. In my âlast lectureâ will address two topics. The first is how I see the future of our field. The second is some personal career advice for my younger colleagues. I have had many successes and some failures, and have observed the careers of many faculty members and doctoral students. I will summarize my observations as actionable advice about being a successful academic while being a happy, contributing human being
Modelling mucociliary clearance
Mathematical modelling of the fluid mechanics of mucociliary clearance (MCC) is reviewed and future challenges for researchers are discussed. The morphology of the bronchial and tracheal airway surface liquid (ASL) and ciliated epithelium are briefly introduced. The cilia beat cycle, beat frequency and metachronal coordination are described, along with the rheology of the mucous layer. Theoretical modelling of MCC from the late 1960s onwards is reviewed, and distinctions between âphenomenologicalâ, âslender body theoryâ and recent âfluidâstructure interactionâ models are explained.\ud
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The ASL consists of two layers, an overlying mucous layer and underlying watery periciliary layer (PCL) which bathes the cilia. Previous models have predicted very little transport of fluid in the PCL compared with the mucous layer. Fluorescent tracer transport experiments on human airway cultures conducted by Matsui et al. [Matsui, H., Randell, S.H., Peretti, S.W., Davis, C.W., Boucher, R.C., 1998. Coordinated clearance of periciliary liquid and mucus from airway surfaces. J. Clin. Invest. 102 (6), 1125â1131] apparently showed equal transport in both the PCL and mucous layer. Recent attempts to resolve this discrepancy by the present authors are reviewed, along with associated modelling findings. These findings have suggested new insights into the interaction of cilia with mucus due to pressure gradients associated with the flat PCL/mucus interface. This phenomenon complements previously known mechanisms for ciliary propulsion. Modelling results are related to clinical findings, in particular the increased MCC observed in patients with pseudohypoaldosteronism. Recent important advances by several groups in modelling the fluidâstructure interaction by which the cilia movement and fluid transport emerge from specification of internal mechanics, viscous and elastic forces are reviewed. Finally, we discuss the limitations of existing work, and the challenges for the next generation of models, which may provide further insight into this complex and vital system
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Potential impact of iodine on tropospheric levels of ozone and other critical oxidants
A new analysis of tropospheric iodine chemistry suggests that under certain conditions this chemistry could have a significant impact on the rate of destruction of tropospheric ozone. In addition, it suggests that modest shifts could result in the critical radical ratio HO2/OH. This analysis is based on the first ever observations of CH3I in the middle and upper free troposphere as recorded during the NASA Pacific Exploratory Mission in the western Pacific. Improved evaluations of several critical gas kinetic and photochemical rate coefficients have also been used. Three iodine source scenarios were explored in arriving at the above conclusions. These include: (1) the assumption that the release of CH3I from the marine environment was the only iodine source with boundary layer levels reflecting a low-productivity source region, (2) same as scenario 1 but with an additional marine iodine source in the form of higher molecular weight iodocarbons, and (3) source scenario 2 but with the release of all iodocarbons occurring in a region of high biological productivity. Based on one-dimensional model simulations, these three source scenarios resulted in estimated Ix (Ix =I + IO + HI + HOI + 2I2O2 +INOx) yields for the upper troposphere of 0.5, 1.5, and 7 parts per trillion by volume (pptv), respectively. Of these, only at the 1.5 and 7 pptv level were meaningful enhancements in O3 destruction estimated. Total column O3 destruction for these cases averaged 6 and 30%, respectively. At present we believe the 1.5 pptv Ix source scenario to be more typical of the tropical marine environment; however, for specific regions of the Pacific (i.e., marine upwelling regions) and for specific seasons of the year, much higher levels might be experienced. Even so, significant uncertainties still remain in the proposed iodine chemistry. In particular, much uncertainty remains in the magnitude of the marine iodine source. In addition, several rate coefficients for gas phase processes need further investigating, as does the efficiency for removal of iodine due to aerosol scavenging processes. Copyright 1996 by the American Geophysical Union
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