Overview study of Space Power Technologies for the advanced energetics program

Space power technologies are reviewed to determine the state-of-the-art and to identify advanced or novel concepts which promise large increases in performance. The potential for incresed performance is judged relative to benchmarks based on technologies which have been flight tested. Space power technology concepts selected for their potentially high performance are prioritized in a list of R & D topical recommendations for the NASA program on Advanced Energetics. The technology categories studied are solar collection, nuclear power sources, energy conversion, energy storage, power transmission, and power processing. The emphasis is on electric power generation in space for satellite on board electric power, for electric propulsion, or for beamed power to spacecraft. Generic mission categories such as low Earth orbit missions and geosynchronous orbit missions are used to distinguish general requirements placed on the performance of power conversion technology. Each space power technology is judged on its own merits without reference to specific missions or power systems. Recommendations include 31 space power concepts which span the entire collection of technology categories studied and represent the critical technologies needed for higher power, lighter weight, more efficient power conversion in space

High-precision photometric redshifts from Spitzer/IRAC : extreme [3.6] - [4.5] colors identify galaxies in the redshift range z ~ 6.6 - 6.9.

One of the most challenging aspects of studying galaxies in the z 7 universe is the infrequent confirmation of their redshifts through spectroscopy, a phenomenon thought to occur from the increasing opacity of the intergalactic medium to Lyα photons at z \u3e 6.5. The resulting redshift uncertainties inhibit the efficient search for [C II] in z ~ 7 galaxies with sub-millimeter instruments such as ALMA, given their limited scan speed for faint lines. One means by which to improve the precision of the inferred redshifts is to exploit the potential impact of strong nebular emission lines on the colors of z ∼ 4 – 8 galaxies as observed by Spitzer/IRAC. At z ~ 6.8, galaxies exhibit IRAC colors as blue as[3.6] [4.5] 1 - ~- , likely due to the contribution of [O III]+Hβ to the 3.6 μm flux combined with the absence of line contamination in the 4.5 μm band. In this paper we explore the use of extremely blue [3.6] [4.5] - colors to identify galaxies in the narrow redshift window z ~ 6.6 – 6.9. When combined with an I-dropout criterion, we demonstrate that we can plausibly select a relatively clean sample of z ~ 6.8 galaxies. Through a systematic application of this selection technique to our catalogs from all five CANDELS fields, we identify 20 probable z ~ 6.6 – 6.9 galaxies. We estimate that our criteria select the ∼50% strongest line emitters at z ~ 6.8 and from the IRAC colors we estimate a typical [O III]+Hb rest-frame equivalent width of 1085 Å for this sample. The small redshift uncertainties on our sample make it particularly well suited for follow-up studies with facilities such as ALMA

Nuclei, Superheavy Nuclei and Hypermatter in a chiral SU(3)-Modell

A model based on chiral SU(3)-symmetry in nonlinear realisation is used for the investigation of nuclei, superheavy nuclei, hypernuclei and multistrange nuclear objects (so called MEMOs). The model works very well in the case of nuclei and hypernuclei with one Lambda-particle and rules out MEMOs. Basic observables which are known for nuclei and hypernuclei are reproduced satisfactorily. The model predicts Z=120 and N=172, 184 and 198 as the next shell closures in the region of superheavy nuclei. The calculations have been performed in self-consistent relativistic mean field approximation assuming spherical symmetry. The parameters were adapted to known nuclei.Comment: 19 pages, 11 figure

Bilijarna funkcija u radnika profesionalno izloženih aluminijskoj prašini i dimu

This study investigated billiary secretory function in workers occupationally exposed to aluminium dust and fumes. It included a group of 34 male workers aged (44.1±7.8) years and exposed up to 4.6 mg m-3 of aluminium dust and fumes in workplace air for (21.6±2.5) years, and a group of 30 unexposed control male workers. Serum and urine aluminium levels were measured in both groups before and after chelating treatment with 1 g deferoxamine by intramuscular injection. Billiary function was assessed by measuring gamma-glutamyl transpeptidase, alkaline phosphatase, 5-nucleotidase, cholesterol and its fractions, total and indirect bilirubin, and bile acids. We then analysed the relationship between Al exposure and billiary function. In the exposed group mean serum aluminium was significantly higher [(4.91±3.86) µg L-1] than in controls. The same was true for urine Al before [(1.57±1.93) µg L-1] and after deferoxamine [(11.51±14.97) µg L-1]. Total and indirect bilirubin and alkaline phosphatase were significantly higher in the exposed than in control workers, and they correlated with urine Al after the chelating treatment. Our findings suggest that chronic occupational exposure to aluminium dust and fumes leads to a significant body retention of aluminium. The impaired biliary secretion in the exposed workers manifested itself in subclinical signs of cholestasis.Eksperimentalna istraživanja na životinjama pokazuju da kronična izloženost aluminiju može izazvati smanjen prijenos organskih aniona preko žučnih kanalića, što ima za posljedicu poremećaje sekrecije žuči i kolestazu. Učinci kronične izloženosti aluminiju na bilijarnu funkciju u ljudi do sada nisu istraživani. Procjenjivali smo učinke na bilijarnu funkciju radnika koji su profesionalno izloženi prašini i dimu aluminija. U izloženoj skupini bila su 34 muškarca, životne dobi (44,1±7,8) godina koji su tijekom (21,6±2,5) godina bili izloženi razini do 4,6 mg m-3 prašine i dima aluminija. Kontrolna skupina sastojala se od 30 neizloženih radnika. Vrijednosti aluminija određene su u serumu i mokraći u obje skupine prije i nakon davanja kelatirajućeg spoja (deferoksamin u dozi od 1 g im.). Za procjenu bilijarne funkcije rabljeni su ovi pokazatelji: γ-glutamil transpeptidaza, alkalna fosfataza, 5-nukleozidaza, kolesterol, ukupni i indirektni bilirubin te žučne kiseline. Analizirana je korelacija između izloženosti aluminiju i bilijarne funkcije. Srednja vrijednost Al u serumu izloženih radnika [(4,91±3,86) µg L-1], kao i koncentracije Al u mokraći prije [(1,57±1,93) µg L-1] i nakon primjene kelatirajućeg spoja [(11,5±15,0) µg L-1] bile su statistički značajno više u odnosu na vrijednosti u kontrolnih ispitanika. Vrijednosti ukupnog i indirektnoog bilirubina te alkalne fosfataze bile su statistički značajno više u izloženih radnika i pozitivno su korelirale s ukupnim Al izlučenim mokraćom nakon primjene kelatora. Može se zaključiti da kronična profesionalna izloženost prašini i dimu aluminija dovodi do tjelesnog opterećenja aluminijem i poremećaja bilijarne funkcije, što se odražava supkliničkim znakovima kolestaze

Incorporating the geometry of dispersal and migration to understand spatial patterns of species distributions

Dispersal and migration can be important drivers of species distributions. Because the paths followed by individuals of many species are curvilinear, spatial statistical models based on rectilinear coordinates systems would fail to predict population connectivity or the ecological consequences of migration or species invasions. I propose that we view migration/dispersal as if organisms were moving along curvilinear geometrical objects called smooth manifolds. In that view, the curvilinear pathways become the ‘shortest realised paths’ arising from the necessity to minimise mortality risks and energy costs. One can then define curvilinear coordinate systems on such manifolds. I describe a procedure to incorporate manifolds and define appropriate coordinate systems, with focus on trajectories (1D manifolds), as parts of mechanistic ecological models. I show how a statistical method, known as ‘manifold learning’, enables one to define the manifold and the appropriate coordinate systems needed to calculate population connectivity or study the effects of migrations (e.g. in aquatic invertebrates, fish, insects and birds). This approach may help in the design of networks of protected areas, in studying the consequences of invasion, range expansions, or transfer of parasites/diseases. Overall, a geometrical view to animal movement gives a novel perspective to the understanding of the ecological role of dispersal and migration

Priority for the Worse Off and the Social Cost of Carbon

The social cost of carbon (SCC) is a monetary measure of the harms from carbon emission. Specifically, it is the reduction in current consumption that produces a loss in social welfare equivalent to that caused by the emission of a ton of CO2. The standard approach is to calculate the SCC using a discounted-utilitarian social welfare function (SWF)—one that simply adds up the well-being numbers (utilities) of individuals, as discounted by a weighting factor that decreases with time. The discounted-utilitarian SWF has been criticized both for ignoring the distribution of well-being, and for including an arbitrary preference for earlier generations. Here, we use a prioritarian SWF, with no time-discount factor, to calculate the SCC in the integrated assessment model RICE. Prioritarianism is a well-developed concept in ethics and theoretical welfare economics, but has been, thus far, little used in climate scholarship. The core idea is to give greater weight to well-being changes affecting worse off individuals. We find substantial differences between the discounted-utilitarian and non-discounted prioritarian SCC

Prolonged institutional rearing is associated with atypically large amygdala volume and difficulties in emotion regulation

Early adversity, for example poor caregiving, can have profound effects on emotional development. Orphanage rearing, even in the best circumstances, lies outside of the bounds of a species-typical caregiving environment. The long-term effects of this early adversity on the neurobiological development associated with socio-emotional behaviors are not well understood. Seventy-eight children, who include those who have experienced orphanage care and a comparison group, were assessed. Magnetic resonance imaging (MRI) was used to measure volumes of whole brain and limbic structures (e.g. amygdala, hippocampus). Emotion regulation was assessed with an emotional go-nogo paradigm, and anxiety and internalizing behaviors were assessed using the Screen for Child Anxiety Related Emotional Disorders, the Child Behavior Checklist, and a structured clinical interview. Late adoption was associated with larger corrected amygdala volumes, poorer emotion regulation, and increased anxiety. Although more than 50% of the children who experienced orphanage rearing met criteria for a psychiatric disorder, with a third having an anxiety disorder, the group differences observed in amygdala volume were not driven by the presence of an anxiety disorder. The findings are consistent with previous reports describing negative effects of prolonged orphanage care on emotional behavior and with animal models that show long-term changes in the amygdala and emotional behavior following early postnatal stress. These changes in limbic circuitry may underlie residual emotional and social problems experienced by children who have been internationally adopted

Modifiable risk factors remain significant causes of medium term mortality after first time Coronary artery bypass grafting

<p>Abstract</p> <p>Background</p> <p>Whilst there is much current data on early outcomes after Coronary artery bypass grafting(CABG), there is relatively little data on medium term outcomes in the current era. The purpose of this study is to present a single surgeon series comprising of all first time CABG patients operated on with the technique of cross clamp fibrillation from Feb-1996 to through to Jan-2003, and to seek risk factors for medium term mortality in these patients.</p> <p>Methods</p> <p>Data was collected from Hospital Episode Statistics and departmental patient administration and tracking systems and cross checked using database techniques. Patient outcomes were searched using the National Health Service strategic tracing service.</p> <p>Results</p> <p>Mean follow up was 5.3 years(0–9.4 years) and was complete for all patients. 30-day survival was 98.4%, 1-year survival 95% and 8-year survival 79%. Cox-regression analysis revealed that several modifiable pre-operative risk factors remain significant predictors of medium term mortality, including Diabetes(Hazard Ratio(HR) 1.73, 95%CI 1.21–2.45), Chromic obstructive pulmonary disease(HR 2.02, 95%CI 1.09–3.72), Peripheral vascular disease(HR 1.68, 95%CI 1.13–2.5), Body mass index>30(HR 1.54, 95%CI 1.08–2.20) and current smoker at operation(HR 1.67, 95%CI 1.03–2.72). However hypertension(HR 1.31, 95%CI 0.95–1.82) and Hypercholestrolaemia(HR 0.81, 95%CI 0.58–1.13) were not predictive which may reflect adequate post-operative control.</p> <p>Conclusion</p> <p>Coronary artery bypass surgery using cross clamp fibrillation is associated with a very low operative mortality. Medium term survival is also good but risk factors such as smoking at operation, Chronic obstructive pulmonary disease, obesity and diabetes negatively impact this survival and should be aggressively treated in the years post-surgery.</p

Energy and system size dependence of \phi meson production in Cu+Cu and Au+Au collisions

We study the beam-energy and system-size dependence of \phi meson production (using the hadronic decay mode \phi -- K+K-) by comparing the new results from Cu+Cu collisions and previously reported Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV measured in the STAR experiment at RHIC. Data presented are from mid-rapidity (|y|<0.5) for 0.4 < pT < 5 GeV/c. At a given beam energy, the transverse momentum distributions for \phi mesons are observed to be similar in yield and shape for Cu+Cu and Au+Au colliding systems with similar average numbers of participating nucleons. The \phi meson yields in nucleus-nucleus collisions, normalised by the average number of participating nucleons, are found to be enhanced relative to those from p+p collisions with a different trend compared to strange baryons. The enhancement for \phi mesons is observed to be higher at \sqrt{s_NN} = 200 GeV compared to 62.4 GeV. These observations for the produced \phi(s\bar{s}) mesons clearly suggest that, at these collision energies, the source of enhancement of strange hadrons is related to the formation of a dense partonic medium in high energy nucleus-nucleus collisions and cannot be alone due to canonical suppression of their production in smaller systems.Comment: 20 pages and 5 figure