Wide-angle sun sensors

Two sensors have been developed: one, single-axis device, is cylindrical; the other, two-axis device, is spherical. Multiple surface deposits of photosensitive material, such as cadmium sulfide, serve as redundancy, ensuring high reliability

Recovery kinetics of winter stressed conifers: The effects of growth light environment, extent of the season, and species.

Evergreens undergo a dramatic reduction in their maximal photochemical efficiency (measured as Fv/Fm) during winter, which is largely due to increases in a sustained form of thermal energy dissipation. Upon removing winter-stressed leaves to room temperature and low light, Fv/Fm recovers over several days and can include both a rapid phase (reversing in minutes) and a slow phase (reversing over days). Both phases are associated with reversal of sustained energy dissipation. Preliminary examination of recovery of evergreens monitored in January in Minnesota showed an absence of the rapid component to recovery. Our goal was to monitor recovery kinetics of sun and shade evergreens in Minnesota throughout winter in order to assess whether the rapid phase of recovery exists early in the winter and converts to the slowly reversible form as winter progresses. Four species of conifers (sun and shade needles) were monitored during the winter of 2007/08: eastern white pine (_Pinus strobus_ L.), balsam fir [_Abies balsamea_ (L.) P. Mill], _Taxus cuspidata_ (L.) and blue spruce (_Picea pungens_ Engelm.). Fv/Fm was measured on dark acclimated needles in the field, twigs were collected, brought indoors and maintained at room temperature and low light where Fv/Fm was monitored for six days. 

The results demonstrated that all species, and both sun and shade needles, showed a rapidly reversible component to recovery in early winter (November). In the sun needles this component was rarely present later in the season, while in the shade needles it was present (although only a small fraction of the total sustained energy dissipation) on most days monitored during winter. The slowly reversible component to sustained energy dissipation was present in both sun and shade needles of all species beginning in November. In all cases, shade needles recovered significantly faster than sun needles. There was a significant slowing of recovery (the slowly reversible component) as winter progressed in both sun and shade needles, and significant differences between species in their recovery response. The results indicate a relatively small contribution of the rapidly reversible component of sustained energy dissipation compared with earlier studies on evergreens growing in the milder winter conditions of Colorado. The results also provide evidence that the rapid component to recovery diminishes as the season progresses, particularly in needles growing in full sun where the slowly reversible component of sustained energy dissipation accounts for most or all of the observed sustained energy dissipation. 
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Sun angle calculator

A circular computer and system is disclosed for determining the sun angle relative to the horizon from any given place and at any time. The computer includes transparent, rotatably mounted discs on both sides of the circular disc member. Printed on one side of the circular disc member are outer and inner circular sets of indicia respectively representative of site longitude and Greenwich Mean Time. Printed on an associated one of the rotatable discs is a set of indicia representative of Solar Time. Printed on the other side of the circular disc member are parallel lines representative of latitude between diametral representations of North and South poles. Elliptical lines extending between the North and South poles are proportionally disposed on the surface to scale Solar Time in hours

Combined sun-acquisition and sun gate-sensor system for spacecraft attitude control

Arrangement combines acquisition and gate functions and reduces sensitivity so that attitude control is effective regardless of changes in solar intensity. There are five photoconductive detectors all electrically interconnected. Detectors are so positioned that, regardless of spacecraft orientation at any instant of interest, at least one detector is illuminated

Mechanical solar motor: A concept

Motor is proposed to convert radiation from sun directly into mechanical energy. Motor utilizes thermal expansion of liquid, heated by sun, as driving force. Unlike most thermally powered systems, it does not require that liquid be converted into vapor

Comparing the effects of sun exposure and vitamin D supplementation on vitamin D insufficiency, and immune and cardio-metabolic function: the Sun Exposure and Vitamin D Supplementation (SEDS) Study

BACKGROUND Adults living in the sunny Australian climate are at high risk of skin cancer, but vitamin D deficiency (defined here as a serum 25-hydroxyvitamin D (25(OH)D) concentration of less than 50 nmol/L) is also common. Vitamin D deficiency may be a risk factor for a range of diseases. However, the optimal strategies to achieve and maintain vitamin D adequacy (sun exposure, vitamin D supplementation or both), and whether sun exposure itself has benefits over and above initiating synthesis of vitamin D, remain unclear. The Sun Exposure and Vitamin D Supplementation (SEDS) Study aims to compare the effectiveness of sun exposure and vitamin D supplementation for the management of vitamin D insufficiency, and to test whether these management strategies differentially affect markers of immune and cardio-metabolic function. METHODS/DESIGN The SEDS Study is a multi-centre, randomised controlled trial of two different daily doses of vitamin D supplementation, and placebo, in conjunction with guidance on two different patterns of sun exposure. Participants recruited from across Australia are aged 18-64 years and have a recent vitamin D test result showing a serum 25(OH)D level of 40-60 nmol/L. DISCUSSION This paper discusses the rationale behind the study design, and considers the challenges but necessity of data collection within a non-institutionalised adult population, in order to address the study aims. We also discuss the challenges of participant recruitment and retention, ongoing engagement of referring medical practitioners and address issues of compliance and participant retention. TRIAL REGISTRATION Australia New Zealand Clinical Trials Registry: ACTRN12613000290796 Registered 14 March 2013

Mariner Mars 1969 sun sensor development

Photodetector and sun sensor development for Mariner Mars 1969 attitude control syste

Sun awareness and sun protection among persons attending dermatology clinics in Malta

On a global level, public awareness of the harmful effects of the sun on the skin, namely skin cancer and photo ageing, has gradually increased largely as a result of ongoing public educational campaigns. In order to assess the current level of knowledge of sun-related skin damage, and to evaluate sun protection habits among Maltese persons (aged 16-50 years) attending dermatology clinics in 3 local hospitals, we undertook a questionnaire survey. A total of 333 valid completed questionnaires were available for evaluation. The vast majority of respondents were aware that exposure to the sun causes skin cancer (93%) and skin ageing (85%). In addition, 69% of the respondents knew that skin cancer can kill. Overall however, this high level of sun awareness is not being translated into safe practice. Occupational sun exposure is substantially greater in men. Notwithstanding this trend men use sunscreens far less than women when out in the sun both at work and during leisure. Pursuing outdoor leisure activities including going to the beach during hours of peak sunshine in spring and summer is popular. The general level of sun protection during leisure is unacceptably low. The media are considered to be by far the most influential source of information on the subject of the sun and the skin. The results of this survey can be used to guide future sun awareness campaigns to focus on issues and population subgroups that need most emphasis.peer-reviewe

White Light Coronograph (WLC) and Ultra-Violet Coronal Spectrometer (UVCS)

The white light coronagraph (WLC) and ultraviolet coronal spectrometer (UVCS) together reveal the corona and the roots of the solar wind from 1.5 to 6 solar radii from Sun center. The WLC measures the plasma density and spatial structure of the corona and coronal mass ejections at a resolution of about 20 arcseconds. The UVCS, in combination with the WLC, measures the temperature and radial outflow speed of the coronal plasma. These instruments will detect mass ejections from active regions and high speed solar wind streams from coronal holes a few days before the source regions rotate onto the face of the Sun, thus giving a week or more of advanced warning for disturbed geomagnetic conditions at Earth