Comparison of thruster configurations in attitude control systems

Several aspects concerning reaction control jet systems as used to govern the attitude of a spacecraft were considered. A thruster configuration currently in use was compared to several new configurations developed in this study. The method of determining the error signals which control the firing of the thrusters was also investigated. The current error determination procedure is explained and a new method is presented. Both of these procedures are applied to each of the thruster configurations which are developed and comparisons of the two methods are made

APEX-CHAMP+ high-J CO observations of low-mass young stellar objects: II. Distribution and origin of warm molecular gas

The origin and heating mechanisms of warm (50<T<200 K) molecular gas in low-mass young stellar objects (YSOs) are strongly debated. Both passive heating of the inner collapsing envelope by the protostellar luminosity as well as active heating by shocks and by UV associated with the outflows or accretion have been proposed. We aim to characterize the warm gas within protosteller objects, and disentangle contributions from the (inner) envelope, bipolar outflows and the quiescent cloud. High-J CO maps (12CO J=6--5 and 7--6) of the immediate surroundings (up to 10,000 AU) of eight low-mass YSOs are obtained with the CHAMP+ 650/850 GHz array receiver mounted on the APEX telescope. In addition, isotopologue observations of the 13CO J=6--5 transition and [C I] 3P_2-3P_1 line were taken. Strong quiescent narrow-line 12CO 6--5 and 7--6 emission is seen toward all protostars. In the case of HH~46 and Ced 110 IRS 4, the on-source emission originates in material heated by UV photons scattered in the outflow cavity and not just by passive heating in the inner envelope. Warm quiescent gas is also present along the outflows, heated by UV photons from shocks. Shock-heated warm gas is only detected for Class 0 flows and the more massive Class I sources such as HH~46. Outflow temperatures, estimated from the CO 6--5 and 3--2 line wings, are ~100 K, close to model predictions, with the exception of the L~1551 IRS 5 and IRAS 12496-7650, for which temperatures <50 K are found. APEX-CHAMP+ is uniquely suited to directly probe a protostar's feedback on its accreting envelope gas in terms of heating, photodissociation, and outflow dispersal by mapping 1'x1' regions in high-J CO and [C I] lines.Comment: 18 pages, accepted by A&A, A version with the figures in higher quality can be found on my website: http://www.cfa.harvard.edu/~tvankemp

Anion dual mode fluoro-chromogenic chemosensor based on a BODIPY core

Herein, we report the synthesis and chromo-fluorogenic behaviour of a BODIPY derivative. The BODIPY core was functionalized with a phenyl group at meso-position and a formyl group at 2-postion introduced through the Vilsmeier Haack reaction. The compound showed an absorption band at 492 nm and an emission band at 508 nm, with a ФF = 0.84. The evaluation of the chemosensing ability of the BODIPY was investigated in the presence of several anions with environmental and biomedical relevance and a simultaneous colorimetric and fluorimetric response was observed for cyanide and fluoride anions.The authors acknowledge Fundação para a Ciência e Tecnologia—FCT (Portugal) for funding through CQUM (UID/QUI/00686/2020) and a Ph.D. grant to. R. C. R. Gonçalves (SFRH/BD/05278/2020). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT

The Formaldehyde Masers in Sgr B2: Very Long Baseline Array and Very Large Array Observations

Observations of two of the formaldehyde (H2CO) masers (A and D) in Sgr B2 using the VLBA+Y27 (resolution ~0.01") and the VLA (resolution ~9") are presented. The VLBA observations show compact sources (<10 milliarcseconds, <80 AU) with brightness temperatures >10^8 K. The maser sources are partially resolved in the VLBA observations. The flux densities in the VLBA observations are about 1/2 those of the VLA; and, the linewidths are about 2/3 of the VLA values. The applicability of a core-halo model for the emission distribution is demonstrated. Comparison with earlier H2CO absorption observations and with ammonia (NH3) observations suggests that H2CO masers form in shocked gas. Comparison of the integrated flux densities in current VLA observations with those in previous observations indicates that (1) most of the masers have varied in the past 20 years, and (2) intensity variations are typically less than a factor of two compared to the 20-year mean. No significant linear or circular polarization is detected with either instrument.Comment: 20 pages, 3 figures, 5 tables, accepted to Ap

A Qualitative Analysis of Gabapentin Misuse and Diversion Among People Who Use Drugs in Appalachian Kentucky

Gabapentin, an anticonvulsant and analgesic for postherpetic neuralgia, has been thought to have no abuse potential despite numerous published reports to the contrary. Gabapentin has been linked with impaired driving and opioid use, highlighting the need to more fully understand its risk profile. Thirty-three individuals reporting recent nonmedical use of gabapentin were recruited from two ongoing longitudinal studies of drug users in Appalachian Kentucky to participate in focus groups. Four sessions were held (two in the community and two in jail settings), during which participants responded to questions regarding their personal experiences with gabapentin misuse. Focus group participants were similar to other gabapentin users in the larger cohort studies with respect to demographics and drug use behaviors. Overall, the sample reported having initiated gabapentin more than 10 years earlier after having it prescribed for a legitimate, though generally off-label, medical indication (e.g., pain, anxiety, opioid detoxification). Participants reported use of gabapentin in combination with buprenorphine, other opioids, cocaine, and caffeine to produce sought-after central nervous system effects (e.g., muscle relaxation, pain reduction, sleep induction, feeling drunk, and feeling “high”). Focus group responses highlighted the low cost of gabapentin for the purpose of getting high and noted increasing popularity in the community, particularly over the last 2 years. Gabapentin was a prominent drug of abuse in two cohorts of the primarily opioid-using individuals. Providers should be aware of gabapentin’s abuse potential, and a reexamination of the need for scheduling is warranted

A New Galactic 6cm Formaldehyde Maser

We report the detection of a new H2CO maser in the massive star forming region G23.71-0.20 (IRAS 18324-0820), i.e., the fifth region in the Galaxy where H2CO maser emission has been found. The new H2CO maser is located toward a compact HII region, and is coincident in velocity and position with 6.7 GHz methanol masers and with an IR source as revealed by Spitzer/IRAC GLIMPSE data. The coincidence with an IR source and 6.7 GHz methanol masers suggests that the maser is in close proximity to an embedded massive protostar. Thus, the detection of H2CO maser emission toward G23.71-0.20 supports the trend that H2CO 6cm masers trace molecular material very near young massive stellar objects.Comment: Accepted for publication in The Astrophysical Journal Letter

Bio mit Gesicht - Erfolgschancen einer kundennahen und innovativen Marketingstrategie

Mangelndes Vertrauen in Bio-Produkte wirkt als eine zentrale Kaufbarriere. Mit der Marketingstrategie Bio mit Gesicht (BMG) soll die Anonymität von Produkten aufgehoben und Vertrauen geschaffen werden, indem die Erzeuger und Verarbeiter im Internet vorgestellt werden. Ziel des Projekts "Bio mit Gesicht – Erfolgschancen einer kundennahen und innovativen Marketingstrategie“ war es, die Markteinführung der Produktlinie BMG wissenschaftlich zu begleiten und praxisrelevante Aussagen über die Konzeption zukünftiger Marketingstrategien zu treffen. Dabei wurde im Rahmen einer quantitativen und einer qualitativen Studie untersucht, worauf das Vertrauen in Bio-Produkte grundsätzlich beruht und ob BMG geeignet ist, das Vertrauen in Bio-Produkte zu steigern. Die Studien zeigen, dass die Kennzeichnung von Bio-Lebensmitteln mit Bio-Labels eine zentrale Rolle dabei spielt, wie Konsumenten deren Vertrauenswürdigkeit beurteilen. Bio-Produkte, die ein Verbandslabel aufweisen, genießen das höchste Vertrauen, gefolgt von staatlichen Labels. Trotz seines geringen Bekanntheitsgrads wirkt auch das BMG-Logo vertrauensbildend. Offenbar erweckt bereits allein das signalgebende Wort „bio“ im Label Vertrauen. Auch schaffen Einkaufsstätten Vertrauen, die aus Sicht der Konsumenten Bio-Produkte aus Überzeugung verkaufen. Regionalität erhöht ebenfalls die Vertrauenswürdigkeit eines Bio-Produkts signifikant. Am höchsten ist das Vertrauen in Bio-Lebensmittel unter Konsumenten, die Bio-Lebensmittel überwiegend in Bio-Läden kaufen. Im Gegensatz zum BMG-Label steigert BMG als Rückverfolgbarkeitssystem via Internet das Vertrauen in Bio-Produkte derzeit kaum. Doch insbesondere durch die zunehmende Verbreitung von Smartphones und den damit verbundenen Vorteil, Produktinformationen noch vor dem Einkauf abrufen zu können, könnte die Bedeutung von BMG zukünftig steigern. Auch die wachsende Bedeutung von elektronischen Lesegeräten, mit denen sich Artikeldaten bereits während des Lebensmitteleinkaufs abrufen lassen, steigert das Potenzial von Rückverfolgbarkeitssystemen. Die Analyse der Zugriffszahlen zeigte zudem, dass in Zeiten eines Lebensmittelskandals (z.B. Dioxin in Eiern, EHEC) die Besucherzahlen auf der Internetseite von BMG deutlich steigen

Observation of twin beam correlations and quadrature entanglement by frequency doubling in a two-port resonator

We demonstrate production of quantum correlated and entangled beams by second harmonic generation in a nonlinear resonator with two output ports. The output beams at wavelength 428.5 nm exhibit 0.9 dB of nonclassical intensity correlations and 0.3 dB of entanglement.Comment: 5 pages, 7 figure

An H2CO 6cm Maser Pinpointing a Possible Circumstellar Torus in IRAS18566+0408

We report observations of 6cm, 3.6cm, 1.3cm, and 7mm radio continuum, conducted with the Very Large Array towards IRAS18566+0408, one of the few sources known to harbor H2CO 6cm maser emission. Our observations reveal that the emission is dominated by an ionized jet at cm wavelengths. Spitzer/IRAC images from GLIMPSE support this interpretation, given the presence of 4.5um excess emission at approximately the same orientation as the cm continuum. The 7mm emission is dominated by thermal dust from a flattened structure almost perpendicular to the ionized jet, thus, the 7mm emission appears to trace a torus associated with a young massive stellar object. The H2CO 6cm maser is coincident with the center of the torus-like structure. Our observations rule out radiative pumping via radio continuum as the excitation mechanism for the H2CO 6cm maser in IRAS18566+0408.Comment: 20 pages, 4 figures, ApJ (in press

Rendering an Account: An Open-State Archive in Postgraduate Supervision

The paper begins with a brief account of the transformation of research degree studies under the pressures of global capitalism and neo-liberal governmentality. A parallel transformation is occurring in the conduct of research through the use of information and communication technologies. Yet the potential of ICTs to shape practices of surveillance or to produce new student-supervisor relations and enhance the processes of developing the dissertation has received almost no critical attention. As doctoral supervisor and student, we then describe the features and uses of a web-based open state archive of the student's work-in-progress, developed by the student and accessible to his supervisor. Our intention was to encourage more open conversations between data and theorising, student and supervisor, and ultimately between the student and professional community. However, we recognise that relations of accountability, as these have developed within a contemporary "audit revolution" (Power, 1994, 1997) in universities, create particular "lines of visibility" (Munro, 1996). Thus while the open-state archive may help to redefine in less managerial terms notions of quality, transparency, flexibility and accountability, it might also make possible greater supervisory surveillance. How should we think about the panoptical potential of this archive? We argue that the diverse kinds of interactional patterns and pedagogical intervention it encourages help to create shifting subjectivities. Moreover, the archive itself is multiple, in bringing together an array of diverse materials that can be read in various ways, by following multiple paths. It therefore constitutes a collage, which we identify as a mode of cognition and of accounting distinct from but related to argument and narrative. As a more "open" text (Iser, 1978) it has an indeterminacy which may render it less open to abuse for the technologies of managerial accountability