Spacecraft cost estimation

Spacecraft subsystem cost estimatio

Computer optimization of reactor-thermoelectric space power systems

A computer simulation and optimization code that has been developed for nuclear space power systems is described. The results of using this code to analyze two reactor-thermoelectric systems are presented

Preliminary impact speed and angle criteria for design of a nuclear airplane fission product containment vessel

Studying aircraft accidents to determine impact angle and speed criteria for designing nuclear airplane fission product containment vesse

The Period protein homolog LIN-42 negatively regulates microRNA biogenesis in C. elegans

AbstractMicroRNAs (miRNAs) are small RNAs that post-transcriptionally regulate gene expression in many multicellular organisms. They are encoded in the genome and transcribed into primary (pri-) miRNAs before two processing steps that ultimately produce the mature miRNA. In order to generate the appropriate amount of a particular miRNA in the correct location at the correct time, proper regulation of miRNA biogenesis is essential. Here we identify the Period protein homolog LIN-42 as a new regulator of miRNA biogenesis in Caenorhabditis elegans. We mapped a spontaneous suppressor of the normally lethal let-7(n2853) allele to the lin-42 gene. Mutations in this allele (ap201) or a second lin-42 allele (n1089) caused increased mature let-7 miRNA levels at most time points when mature let-7 miRNA is normally expressed. Levels of pri-let-7 and a let-7 transcriptional reporter were also increased in lin-42(n1089) worms. These results indicate that LIN-42 normally represses pri-let-7 transcription and thus the accumulation of let-7 miRNA. This inhibition is not specific to let-7, as pri- and mature levels of lin-4 and miR-35 were also increased in lin-42 mutants. Furthermore, small RNA-seq analysis showed widespread increases in the levels of mature miRNAs in lin-42 mutants. Thus, we propose that the period protein homolog LIN-42 is a global regulator of miRNA biogenesis

In search of community history

This editorial response to the preceding article by Dennis Mills addresses the meaning of community history. Rejecting an over-tight definition, we argue for a methodologically distinct community history, combining a micro-historical approach with a sensitivity to the discursive construction of the term 'community'. Furthermore the role of family and community historians should be to adapt a critical stance towards contemporary meanings of both past 'communities' and past 'families'. The article concludes that Withington and Shephard's schema for approaching the history of 'community' offers a practical way forward for the family and community historian

Soccer Football Pools Act, 1981, No. 26

Purpose We aimed to assess the effectiveness of acupuncture for cancer-related fatigue (CRF) in patients with breast cancer. Patients and Methods We conducted a pragmatic, randomized controlled trial comparing acupuncture with enhanced usual care. Three hundred two outpatients with breast cancer participated. We randomly assigned 75 patients to usual care and 227 patients to acupuncture plus usual care (random assignment of 1: 3 respectively) with minimization controlling for baseline general fatigue and maintenance treatment. Treatment was delivered by acupuncturists once a week for 6 weeks through needling three pairs of acupoints. The usual care group received a booklet with information about fatigue and its management. Primary outcome was general fatigue at 6 weeks, measured with the Multidimensional Fatigue Inventory (MFI). Other measurements included the Hospital Anxiety and Depression Scale, Functional Assessment of Cancer Therapy-General quality-of-life scale, and expectation of acupuncture effect. Analyses were by intention to treat. Results Two hundred forty-six of 302 patients randomly assigned provided complete data at 6 weeks. The difference in the mean General Fatigue score, between those who received the intervention and those who did not, was -3.11 (95% CI, -3.97 to -2.25; P<.001). The intervention also improved all other fatigue aspects measured by MFI, including Physical Fatigue and Mental Fatigue (acupuncture effect, -2.36 and -1.94, respectively; both at P<.001), anxiety and depression (acupuncture effect, -1.83 and -2.13, respectively; both at P<.001), and quality of life (Physical Well-Being effect, 3.30; Functional Well-Being effect, 3.57; both at P<.001; Emotional Well-Being effect, 1.93; P=.001; and Social Functioning Well-Being effect, 1.05; P<.05). Conclusion Acupuncture is an effective intervention for managing the symptom of CRF and improving patients' quality of life. J Clin Oncol 30:4470-4476. (C) 2012 by American Society of Clinical Oncolog

A connection between star formation activity and cosmic rays in the starburst galaxy M 82

Although Galactic cosmic rays (protons and nuclei) are widely believed to be dominantly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery [1]. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size, more than 50 times the diameter of similar Galactic regions, uniquely enables reliable calorimetric measurements of their potentially high cosmic-ray density [2]. The cosmic rays produced in the formation, life, and death of their massive stars are expected to eventually produce diffuse gamma-ray emission via their interactions with interstellar gas and radiation. M 82, the prototype small starburst galaxy, is predicted to be the brightest starburst galaxy in gamma rays [3, 4]. Here we report the detection of >700 GeV gamma rays from M 82. From these data we determine a cosmic-ray density of 250 eV cm-3 in the starburst core of M 82, or about 500 times the average Galactic density. This result strongly supports that cosmic-ray acceleration is tied to star formation activity, and that supernovae and massive-star winds are the dominant accelerators.Comment: 18 pages, 4 figures; published in Nature; Version is prior to Nature's in-house style editing (differences are minimal

Status of the VERITAS Observatory

VERITAS, an Imaging Atmospheric Cherenkov Telescope (IACT) system for gammma-ray astronomy in the GeV-TeV range, has recently completed its first season of observations with a full array of four telescopes. A number of astrophysical gamma-ray sources have been detected, both galactic and extragalactic, including sources previously unknown at TeV energies. We describe the status of the array and some highlight results, and assess the technical performance, sensitivity and shower reconstruction capabilities.Comment: Submitted to Proceedings of "4th Heidelberg International Symposium on High Energy Gamma-Ray Astronomy 2008

Discovery of Very High-Energy Gamma-Ray Radiation from the BL Lac 1ES 0806+524

The high-frequency-peaked BL-Lacertae object \objectname{1ES 0806+524}, at redshift z=0.138, was observed in the very-high-energy (VHE) gamma-ray regime by VERITAS between November 2006 and April 2008. These data encompass the two-, and three-telescope commissioning phases, as well as observations with the full four-telescope array. \objectname{1ES 0806+524} is detected with a statistical significance of 6.3 standard deviations from 245 excess events. Little or no measurable variability on monthly time scales is found. The photon spectrum for the period November 2007 to April 2008 can be characterized by a power law with photon index $3.6 \pm 1.0_{\mathrm{stat}} \pm 0.3_{\mathrm{sys}}$ between $\sim$300 GeV and $\sim$700 GeV. The integral flux above 300 GeV is $(2.2\pm0.5_{\mathrm{stat}}\pm0.4_{\mathrm{sys}})\times10^{-12}\:\mathrm{cm}^{2}\:\mathrm{s}^{-1}$ which corresponds to 1.8% of the Crab Nebula flux. Non contemporaneous multiwavelength observations are combined with the VHE data to produce a broadband spectral energy distribution that can be reasonably described using a synchrotron-self Compton model.Comment: 14 pages, 4 figures, accepted to APJ

Roadmaps to Utopia: Tales of the Smart City

Notions of the Smart City are pervasive in urban development discourses. Various frameworks for the development of smart cities, often conceptualized as roadmaps, make a number of implicit claims about how smart city projects proceed but the legitimacy of those claims is unclear. This paper begins to address this gap in knowledge. We explore the development of a smart transport application, MotionMap, in the context of a £16M smart city programme taking place in Milton Keynes, UK. We examine how the idealized smart city narrative was locally inflected, and discuss the differences between the narrative and the processes and outcomes observed in Milton Keynes. The research shows that the vision of data-driven efficiency outlined in the roadmaps is not universally compelling, and that different approaches to the sensing and optimization of urban flows have potential for empowering or disempowering different actors. Roadmaps tend to emphasize the importance of delivering quick practical results. However, the benefits observed in Milton Keynes did not come from quick technical fixes but from a smart city narrative that reinforced existing city branding, mobilizing a growing network of actors towards the development of a smart region. Further research is needed to investigate this and other smart city developments, the significance of different smart city narratives, and how power relationships are reinforced and constructed through them