Multispectral scanner optical system

An optical system for use in a multispectral scanner of the type used in video imaging devices is disclosed. Electromagnetic radiation reflected by a rotating scan mirror is focused by a concave primary telescope mirror and collimated by a second concave mirror. The collimated beam is split by a dichroic filter which transmits radiant energy in the infrared spectrum and reflects visible and near infrared energy. The long wavelength beam is filtered and focused on an infrared detector positioned in a cryogenic environment. The short wavelength beam is dispersed by a pair of prisms, then projected on an array of detectors also mounted in a cryogenic environment and oriented at an angle relative to the optical path of the dispersed short wavelength beam

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

Multifactorial analysis of human blood cell responses to clinical total body irradiation

Multiple regression analysis techniques are used to study the effects of therapeutic radiation exposure, number of fractions, and time on such quantal responses as tumor control and skin injury. The potential of these methods for the analysis of human blood cell responses is demonstrated and estimates are given of the effects of total amount of exposure and time of protraction in determining the minimum white blood cell concentration observed after exposure of patients from four disease groups

Assessment of free-living nitrogen fixing microorganisms for commercial nitrogen fixation

Ammonia production by Klebsiella pneumoniae is not economical with present strains and improving nitrogen fixation to its theoretical limits in this organism is not sufficient to achieve economic viability. Because the value of both the hydrogen produced by this organism and the methane value of the carbon source required greatly exceed the value of the ammonia formed, ammonia (fixed nitrogen) should be considered the by-product. The production of hydrogen by KLEBSIELLA or other anaerobic nitrogen fixers should receive additional study, because the activity of nitrogenase offers a significant improvement in hydrogen production. The production of fixed nitrogen in the form of cell mass by Azotobacter is also uneconomical and the methane value of the carbon substrate exceeds the value of the nitrogen fixed. Parametric studies indicate that as efficiencies approach the theoretical limits the economics may become competitive. The use of nif-derepressed microorganisms, particularly blue-green algae, may have significant potential for in situ fertilization in the environment

Structural assembly in space

A cost algorithm for predicting assembly costs for large space structures is given. Assembly scenarios are summarized which describe the erection, deployment, and fabrication tasks for five large space structures. The major activities that impact total costs for structure assembly from launch through deployment and assembly to scientific instrument installation and checkout are described. Individual cost elements such as assembly fixtures, handrails, or remote minipulators are also presented

Teen Fertility and Gender Inequality in Education

Previous studies in developed countries have found a micro-level association between teenage fertility and girls’ educational attainment but researchers still debate the policy implications of these associations. First, are these associations causal? Second, are they substantively important enough, at the macro-level, to warrant policy attention? In other words, how much would policy efforts to reduce unintended pregnancy among teens pay off in terms of narrowing national gender gaps in educational attainment? Third, under what contexts are these payoffs likely to be important? This paper focuses on the latter two questions. We begin by proposing a contextual hypothesis to explain cross-national variation in the gender-equity payoffs from reducing unintended teen fertility. We then test this hypothesis, using DHS data from 38 countries.gender equity, life tables, population and development, teen fertility

Demographic transitions and children's resources: growth or divergence?

How do fertility transitions affect children’s resource endowments? Existing perspectives provide two seemingly different answers: Dilution arguments focusing on family size predict an average gain, while divergence arguments focusing on family structure predict increased inequality. We attempt to integrate these two perspectives, to show how changes in family size and structure additively and interactively shape the levels and inequality in children’s resource endowments. Failure to consider these interactions can severely bias estimates of the magnitude or even direction of the influences of fertility transitions. An empirical illustration is provided with Cameroon data.children’s resources, decomposition, family size, family structure, fertility transition, inequality, resource dilution, simulation

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