Analytical expressions for optimum alignment modes of highly segmented mirrors

The major sources causing deterioration of optical quality in extremely large optical telescopes are misadjustments of the mirrors, deformations of monolithic mirrors, and misalignments of segments in segmented mirrors. For active optics corrections, all three errors, which can partially compensate each other, are measured simultaneously. It is therefore of interest to understand the similarities and differences between the three corresponding types of modes which describe these errors. The first two types are best represented by Zernike polynomials and elastic modes respectively, both of them being continuous and smooth functions. The segment misaligment modes, which are derived by singular value decomposition, are by their nature not smooth and in general discontinuous. However, for mirrors with a large number of segments, the lowest modes become effectively both smooth and continuous. This paper derives analytical expressions for these modes, using differential operators and their adjoints, for the limit case of infinitesimally small segments. For segmented mirrors with approximately 1000 segments, it is shown that these modes agree well with the corresponding lowest singular value decomposition modes. Furthermore, the analytical expressions reveal the nature of the segment misalignment modes and allow for a detailed comparison with the elastic modes of monolithic mirrors. Some mathematical features emerge as identical in the two cases.Comment: 24 pages, 13 figures, accepted for publication in Journal of Modern Optic

“Who has not trembled at the Mohocks' name?”: Narratives of Control and Resistance in the Press in Early Eighteenth-Century London

The Mohocks were a rake gang that terrorized the streets of eighteenth-century London in the spring of 1712, but their reputation was the result of a panic propagated by newspapers and pamphlets. The presentation of the rakes is influenced by competing agendas; the agenda can be one of control and cohesion, where the criminal is an adversarial source of social disruption that unifies society through opposition to it. This agenda is countered by a rejection and mockery of the control narrative, where fear-mongering is ridiculed as a tool of authorities who are morally equivalent to the criminals they condemn. The print production surrounding the Mohocks, as well as John Gay's plays, The Mohocks and The Beggar's Opera, show that the agendas of authority and rebellion often appear side by side. The texts examined here express a liberal yearning for personal freedom as well as a conservative desire for security

Alfalfa in Beef Backgrounding Programs

Alfalfa can be a very important part of most beef backgrounding operations. Today I want to look at two ideas about alfalfa. First, why we should consider making alfalfa our most important crop on a farm that\u27s backgrounding. Secondly, what are some of the ways to best utilize the alfalfa we do produce? We can say a lot of positive things about why alfalfa can be important to a beef backgrounder. In preparing for this presentation, I talked with several producers about why they grow and feed alfalfa. Most often I came away with the thought: Alfalfa improves cash flow

HD.gov 2.0: An Interagency Web Portal on the Human Dimensions of Natural Resource Management.

The HD.Gov (HumanDimensions.gov) website was conceptualized in collaboration with NOAA, the Forest Service, National Park Service, and other agencies with the intention of providing public access to federal agency social science resources. Originally developed and hosted by NOAA, during the winter of 2011 the USGS Fort Collins Science Center worked with NOAA staff to migrate the HD.Gov database, application, and website to a USGS hosting center. HD.gov provides a credible, reliable human dimensions web portal that connects two distinct communities, those who develop social science information and tools, and the natural resource managers who need the information and tools. HD.gov is a collaboration of government, academic and nongovernmental organizations that enables partners to submit, peer review and distribute social science content

Community pharmacy type 2 diabetes risk assessment: demographics and risk results

Objectives: To determine the demographics and risk results of patients accessing a community pharmacy diabetes risk assessment service. Method: Participating patients underwent an assessment using a validated questionnaire to determine their 10-year risk of developing type 2 diabetes. Patients were given appropriate lifestyle advice or referred to their general practitioner if necessary. Key findings: In total, 21 302 risk assessments were performed. Nearly one-third (29%) of 3427 risk assessments analysed yielded a result of moderate or high chance of developing the condition. Conclusions: Community pharmacies can identify a significant number of patients at risk of developing type 2 diabetes in the next 10 years. Further follow-up work needs to be done to determine the cost-effectiveness of such a service and the consequences of receiving a risk assessment

The reversal of essential fatty acid deficiency symptoms in the cheetah

Two members of the Order Carnivore (the lion and the domestic cat) are known to be Δ-6-desaturase deficient. Two anoestrous 8-year-old female cheetahs exhibiting symptoms consistent with essential fatty acid (EFA) deficiency were treated with encapsulated natural oils as supplement to their normal meat diet. The condition of both animals improved markedly, they came into full oestrus, mated, became pregnant, and have since produced healthy litters of cubs. This may be the first indication of a possible requirement for Δ-6-desaturase reaction products in this species