1,271 research outputs found
Your community gets a B-: analysis of the specific and curious realm of airport bond rating
Commercial airports are publicly-owned transportation infrastructure, usually funded with bonds. The bond rating decision for these entities thus has important ramifications for bond investors, issuers, airport managers, and even the communities the airports serve, but the rating decision process is not well understood. This paper discusses a simulation of the rating process in two decision environments, including a downgrade. The effect of information framing in an environment of incomplete data is examined using amateur evaluators. Amateur evaluators were utilized to understand how people with limited financial analysis skills would respond when presented with incomplete information and a primed scenario. The results indicate that amateur evaluators were more likely to downgrade a bond grade than a ratings agency, but this effect was moderated for amateur evaluators with more work experience. Implications for airport and supply chain infrastructure are discussed
Direct observation of charge inversion by multivalent ions as a universal electrostatic phenomenon
We have directly observed reversal of the polarity of charged surfaces in
water upon the addition of tri- and quadrivalent ions using atomic force
microscopy. The bulk concentration of multivalent ions at which charge
inversion reversibly occurs depends only very weakly on the chemical
composition, surface structure, size and lipophilicity of the ions, but is
dominated by their valence. These results support the theoretical proposal that
spatial correlations between ions are the driving mechanism behind charge
inversion.Comment: submitted to PRL, 26-04-2004 Changed the presentation of the theory
at the end of the paper. Changed small error in estimate of prefactor ("w" in
first version) of equation
Tolerability and safety of the intake of bovine milk oligosaccharides extracted from cheese whey in healthy human adults.
Mechanistic research suggests a unique evolutionary relationship between complex milk oligosaccharides and cognate bifidobacteria enriched in breast-fed infants. Bovine milk oligosaccharides (BMO) were recently identified as structurally and functionally similar to human milk oligosaccharides. The present single-blind three-way crossover study is the first to determine the safety and tolerability of BMO consumption by healthy human participants (n 12) and its effects on faecal microbiota and microbial metabolism. Participants consumed each supplement (placebo-control; low- and high-BMO doses) for eleven consecutive days, followed by a 2-week washout period prior to initiating the next supplement arm. Low and high BMO doses were consumed as 25 and 35 % of each individual's daily fibre intake, respectively. Safety and tolerability were measured using standardised questionnaires on gut and stomach discomfort and stool consistency. Faecal extracts were profiled for bacterial populations by next-generation sequencing (NGS) and bifidobacteria presence was confirmed using quantitative PCR. Urine was analysed for changes in microbial metabolism using nuclear magnetic resonance spectroscopy (1H-NMR). Consumption of both the low and high BMO doses was well tolerated and did not change stool consistency from baseline. Multivariate analysis of the NGS results demonstrated no change in faecal microbiota phyla among the placebo-control and BMO supplement groups. In conclusion, BMO supplementation was well tolerated in healthy adults and has the potential to shift faecal microbiota toward beneficial strains as part of a synbiotic treatment with probiotic cultures that selectively metabolise oligosaccharides
Lessons Learned From a Collaborative to Improve Care for Patients With Diabetes in 17 Community Health Centers, Massachusetts, 2006
INTRODUCTION: In 2006, the Massachusetts League of Community Health Centers convened a collaborative to systematically improve health care delivery for patients with diabetes in 17 community health centers. Our goal was to identify facilitators of and barriers to success reported by teams that participated in this collaborative.
METHODS: The collaborative\u27s activities lasted 13 months. At their conclusion, we interviewed participating team members. We asked about their teams\u27 successes, challenges, and take-home messages for future collaborative efforts. We organized their responses into common themes by using the Chronic Care Model as a framework.
RESULTS: Themes that emerged as facilitators of success included shifting clinic focus to more actively involve patients and to promote their self-management; improving the understanding and implementation of professional guidelines; and expanding staff roles to accommodate these goals. Patient registries were perceived as beneficial but lacking adequate technical support. Other barriers were staffing and time constraints.
CONCLUSION: Cooperative efforts to improve health care delivery for people with diabetes may benefit from educating the health care team about guidelines, establishing a stronger role for the patient as part of the health care team, and providing adequate technical instruction and support for the use of clinical databases
Limitations and challenges of EIT-based monitoring of stroke volume and pulmonary artery pressure.
Electrical impedance tomography (EIT) shows potential for radiation-free and noninvasive hemodynamic monitoring. However, many factors degrade the accuracy and repeatability of these measurements. Our goal is to estimate the impact of this variability on the EIT-based monitoring of two important central hemodynamic parameters: stroke volume (SV) and pulmonary artery pressure (PAP).
We performed simulations on a 4D ([Formula: see text]) bioimpedance model of a human volunteer to study the influence of four potential confounding factors (electrode belt displacement, electrode detachment, changes in hematocrit and lung air volume) on the performance of EIT-based SV and PAP estimation. Results were used to estimate how these factors affect the EIT measures of either absolute values or relative changes (i.e. trending).
Our findings reveal that the absolute measurement of SV via EIT is very sensitive to electrode belt displacements and lung conductivity changes. Nonetheless, the trending ability of SV EIT might be a promising alternative. The timing-based measurement of PAP is more robust to lung conductivity changes but sensitive to longitudinal belt displacements at severe hypertensive levels and to rotational displacements (independent of the PAP level).
We identify and quantify the challenges of EIT-based SV and PAP monitoring. Absolute SV via EIT is challenging, but trending is feasible, while both the absolute and trending of PAP via EIT are mostly impaired by belt displacements
Determining Distribution and Size of Larval Pacific Geoduck Clams (Panopea Generosa Gould 1850) in Quartermaster Harbor (Washington, USA) Using a Novel Sampling Approach
Realistic species-specific information about larval life history is necessary for effective management of shellfish and parameterization of larval connectivity models. The patchiness of dispersing larvae, and the resources needed for sorting and identifying them, has limited many studies of larval distribution in the field, especially for species that are less common. In particular, little is known about in situ larval distribution of Pacific geoduck clams (Panopea generosa Gould 1850), a commercially important species found in Puget Sound, WA. A novel approach-time-integrating larval tube traps paired with molecular identification and sorting (FISH-CS)-was used to determine the distribution of geoduck larvae over 4 moat 3 stations in Quartermaster Harbor. Larvae were found consistently at the surface and thermocline rather than at the bottom. More and larger larvae were captured in the inside and middle of the harbor than the outer harbor, indicating at least some larval retention. Two pulses of larvae were captured, in March and late May to early June. Size frequency distributions of larvae indicate that these were 2 separate cohorts of larvae, with the possibility of a pulse of larvae from elsewhere toward the end of the season. The only physical parameter associated with relative larval abundance was degree of stratification, although the association was weak. These data represent the first reported study of geoduck larval distribution in the field and the first use of the FISH-CS technique for field collections. In the future, this approach can be used to answer many relevant management questions locally and more broadly, including quantifying larval export from shellfish farms, placement of restoration sites and marine protected areas, and spread of invasive species
Role of osmotic and hydrostatic pressures in bacteriophage genome ejection
A critical step in the bacteriophage life cycle is genome ejection into host
bacteria. The ejection process for double-stranded DNA phages has been studied
thoroughly \textit{in vitro}, where after triggering with the cellular receptor
the genome ejects into a buffer. The experimental data have been interpreted in
terms of the decrease in free energy of the densely packed DNA associated with
genome ejection. Here we detail a simple model of genome ejection in terms of
the hydrostatic and osmotic pressures inside the phage, a bacterium, and a
buffer solution/culture medium. We argue that the hydrodynamic flow associated
with the water movement from the buffer solution into the phage capsid and
further drainage into the bacterial cytoplasm, driven by the osmotic gradient
between the bacterial cytoplasm and culture medium, provides an alternative
mechanism for phage genome ejection \textit{in vivo}; the mechanism is
perfectly consistent with phage genome ejection \textit{in vitro}.Comment: 5 pages, 2 figures, references update
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