Dosimetry for radiobiological studies of the human hematopoietic system

A system for estimating individual bone marrow doses in therapeutic radiation exposures of leukemia patients was studied. These measurements are used to make dose response correlations and to study the effect of dose protraction on peripheral blood cell levels. Three irradiators designed to produce a uniform field of high energy gamma radiation for total body exposures of large animals and man are also used for radiobiological studies

Access to Mobile Resources: How Does It Affect the Clerkship Experience?

Objectives: To evaluate the perceived benefits of access to library-licensed mobile clinical decision support resources in clinical medical education. Methods: A cohort of medical students was surveyed midway through the clerkship year. Dana Medical Library offered instruction on clinical mobile resources at the beginning of the year. Students were offered a subject guide and assistance with authentication. Assessment methods included web analytics measuring the utility of the subject guide and a survey. Survey questions gathered data on access to mobile devices, relevance of instruction, use of library-licensed mobile resources, and benefits and barriers to their use in the clinical setting. Students were also asked whether access to mobile resources facilitated comparable educational experiences across clerkship sites. Results: The survey was sent to all 111 students from the University of Vermont College of Medicine class of 2014; 31 completed the survey, with a completion rate of 28%. All respondents owned a mobile device, despite efforts to recruit both users and non-users. Nearly 75% of respondents reported using an iPhone. About 90% of respondents brought their mobile device on rotation. Generally, the wireless access at each clerkship site was rated good or excellent. Of the 60% of respondents who attended the instruction session on mobile resources, 94% found the class helpful. Half of the respondents looked at the Mobile Apps subject guide; 70% of those who did found it helpful. A significant increase in page views was reflected in subject guide usage statistics immediately following the instruction session. Approximately 25% of respondents sought out individual assistance at the library. Conclusions: Respondents suggested improvements to library instruction such as distributing access codes during the class and demonstrating installation of an app. A large number of students did not seek additional assistance from the library, citing they did not have any questions. While that may be because they found the subject guide and/or class sufficiently helpful, a significant number of respondents indicated they were unaware of the subject guide. This suggests a need for further promotion and marketing efforts. Researchers were surprised that nonlibrary licensed apps (ePocrates or Medscape) were valued over resources such as DynaMed, and that the most common barrier cited was not having access to appropriate apps. Finally, almost all of the participants who reported taking a mobile device on a rotation agreed it facilitated access to clinical information and improved the clerkship experience

Library Support Of Mobile Resources During Clinical Clerkships

In response to frequent use of mobile devices among medical students, Dana Medical Library at the University of Vermont provided mobile resource support to medical students preparing for clerkships. The librarians offered group instruction, individual assistance, and an online subject guide. These activities were assessed through evaluations, web statistics, and a survey. Survey questions gathered data on access to mobile devices, use of library-licensed mobile resources, and benefits and barriers to use in the clinical setting. The majority of survey respondents believed access to mobile resources improved their clerkship experience and contributed to comparable educational experiences across clerkship sites. Researchers found that library support impacted student perception of the value of mobile resources in the clerkship experience

Backarc basin and ocean island basalts in the Narooma Accretionary Complex, Australia: setting, geochemistry and tectonics

The Cambrian-Ordovician Wagonga Group contains basalts at Melville Point and Barlings Beach, 20 km south of Batemans Bay, New South Wales. At Melville Point, the succession has basal altered basalts overlain by chert and interbedded siliceous mudstone of the Wagonga Group, in turn overlain by turbidites and chert of the Adaminaby Group with a latest Cambrian to earliest Ordovician age. By contrast, at Barlings Beach, basalt is associated with highly disrupted chert (tectonic mélange), various slivers of mudstone and turbidites, and turbidites of the Adaminaby Group. Immobile elements in the basalts show consistent patterns that allow the magmatic affinity and tectonic setting to be determined in spite of pervasive hydrothermal alteration and subsequent lower greenschist facies metamorphism that accompanied strong folding and multiple foliation development. The Melville Point basalts show Ti/V ratios transitional between arc and MORB and therefore may have formed in either a forearc or backarc basin setting. However, these rocks have higher Ti/V ratios, LREE, Th and Nb than found in forearc basalts and are therefore considered to have formed in a backarc basin setting. In contrast to Melville Point, most basalts at Barlings Beach have a geochemical signature distinctive of ocean island settings like those reported from elsewhere in the Wagonga Group. We believe these rocks developed in a Cambrian backarc basin setting. In the Early to Middle Ordovician, much of the ocean basin was inundated by quartzose turbidites followed by basin destruction with accretion/underplating at a Late Ordovician-early Silurian Benambran subduction zone and formation of the Narooma Accretionary Complex

Analysing changes to the flow of public funding within local health and care systems: An adaptation of the System of Health Accounts framework to a local health system in England

Financial flows relating to health care are routinely analysed at national and international level. They have rarely been systematically analysed at local level, despite sub-national variation due to population needs and decisions enacted by local organisations. We illustrate an adaptation of the System of Health Accounts framework to map the flow of public health and care funding within local systems, with an application for Greater Manchester (GM), an area in England which agreed a health and social care devolution deal with the central government in 2016. We analyse how financial flows changed in GM during the four years post-devolution, and whether spending was aligned with local ambitions to move towards prevention of ill-health and integration of health and social care. We find that GM decreased spending on public health by 15%, and increased spending on general practice by 0.1% in real terms. The share of total local expenditure paid to NHS Trusts for general and acute services increased from 70.3% to 71.6%, while that for community services decreased from 11.7% to 10.3%. Results suggest that GM may have experienced challenges in redirecting resources towards their goals. Mapping financial flows at a local level is a useful exercise to examine whether spending is aligned with system goals and highlight areas for further investigation

Network formation of tissue cells via preferential attraction to elongated structures

Vascular and non-vascular cells often form an interconnected network in vitro, similar to the early vascular bed of warm blooded embryos. Our time-lapse recordings show that the network forms by extending sprouts, i.e., multicellular linear segments. To explain the emergence of such structures, we propose a simple model of preferential attraction to stretched cells. Numerical simulations reveal that the model evolves into a quasi-stationary pattern containing linear segments, which interconnect above the critical volume fraction of 0.2. In the quasi-stationary state the generation of new branches offset the coarsening driven by surface tension. In agreement with empirical data, the characteristic size of the resulting polygonal pattern is density-independent within a wide range of volume fractions

A phenomenological approach to normal form modeling: a case study in laser induced nematodynamics

An experimental setting for the polarimetric study of optically induced dynamical behavior in nematic liquid crystal films has allowed to identify most notably some behavior which was recognized as gluing bifurcations leading to chaos. This analysis of the data used a comparison with a model for the transition to chaos via gluing bifurcations in optically excited nematic liquid crystals previously proposed by G. Demeter and L. Kramer. The model of these last authors, proposed about twenty years before, does not have the central symmetry which one would expect for minimal dimensional models for chaos in nematics in view of the time series. What we show here is that the simplest truncated normal forms for gluing, with the appropriate symmetry and minimal dimension, do exhibit time signals that are embarrassingly similar to the ones found using the above mentioned experimental settings. The gluing bifurcation scenario itself is only visible in limited parameter ranges and substantial aspect of the chaos that can be observed is due to other factors. First, out of the immediate neighborhood of the homoclinic curve, nonlinearity can produce expansion leading to chaos when combined with the recurrence induced by the homoclinic behavior. Also, pairs of symmetric homoclinic orbits create extreme sensitivity to noise, so that when the noiseless approach contains a rich behavior, minute noise can transform the complex damping into sustained chaos. Leonid Shil'nikov taught us that combining global considerations and local spectral analysis near critical points is crucial to understand the phenomenology associated to homoclinic bifurcations. Here this helps us construct a phenomenological approach to modeling experiments in nonlinear dissipative contexts.Comment: 25 pages, 9 figure

Weather modification by carbon dust absorption of solar energy

July, 1974.Includes bibliographical references

Observation of sub-Poisson photon statistics in the cavity-QED microlaser

We have measured the second-order correlation function of the cavity-QED microlaser output and observed a transition from photon bunching to antibunching with increasing average number of intracavity atoms. The observed correlation times and the transition from super- to sub-Poisson photon statistics can be well described by gain-loss feedback or enhanced/reduced restoring action against fluctuations in photon number in the context of a quantum microlaser theory and a photon rate equation picture. However, the theory predicts a degree of antibunching several times larger than that observed, which may indicate the inadequacy of its treatment of atomic velocity distributions.Comment: 4 pages, 4 figure