MAS2-8 radar and digital control unit

The design of the MAS 2-8 (2 to 8 GHz microwave-active spectrometer), a ground-based sensor system, is presented. A major modification in 1974 to the MAS 2-8, that of a control subsystem to automate the data-taking operation, is the prime focus. The digital control unit automatically changes all system parameters except FM rate and records the return signal on paper tape. The overall system operation and a detailed discussion of the design and operation of the digital control unit are presented

A cold complex chemistry toward the low-mass protostar B1-b: evidence for complex molecule production in ices

Gas-phase complex organic molecules have been detected toward a range of high- and low-mass star-forming regions at abundances which cannot be explained by any known gas-phase chemistry. Recent laboratory experiments show that UV irradiation of CH3OH-rich ices may be an important mechanism for producing complex molecules and releasing them into the gas-phase. To test this ice formation scenario we mapped the B1-b dust core and nearby protostar in CH3OH gas using the IRAM 30m telescope to identify locations of efficient non-thermal ice desorption. We find three CH3OH abundance peaks tracing two outflows and a quiescent region on the side of the core facing the protostar. The CH3OH gas has a rotational temperature of ~10 K at all locations. The quiescent CH3OH abundance peak and one outflow position were searched for complex molecules. Narrow, 0.6-0.8 km s-1 wide, HCOOCH3 and CH3CHO lines originating in cold gas are clearly detected, CH3OCH3 is tentatively detected and C2H5OH and HOCH2CHO are undetected toward the quiescent core, while no complex molecular lines were found toward the outflow. The core abundances with respect to CH3OH are ~2.3% and 1.1% for HCOOCH3 and CH3CHO, respectively, and the upper limits are 0.7-1.1%, which is similar to most other low-mass sources. The observed complex molecule characteristics toward B1-b and the pre-dominance of HCO-bearing species suggest a cold ice (below 25 K, the sublimation temperature of CO) formation pathway followed by non-thermal desorption through e.g. UV photons traveling through outflow cavities. The observed complex gas composition together with the lack of any evidence of warm gas-phase chemistry provide clear evidence of efficient complex molecule formation in cold interstellar ices.Comment: 23 pages, 7 figures, accepted for publication in Ap

Formation rates of complex organics in UV irradiated CH3OH-rich ices I: Experiments

(Abridged) Gas-phase complex organic molecules are commonly detected in the warm inner regions of protostellar envelopes. Recent models show that photochemistry in ices followed by desorption may explain the observed abundances. This study aims to experimentally quantify the broad-band UV-induced production rates of complex organics in CH3OH-rich ices at 20-70 K under ultra-high vacuum conditions. The reaction products are mainly identified by RAIRS and TPD experiments. Complex organics are readily formed in all experiments, both during irradiation and during a slow warm-up of the ices to 200 K after the UV lamp is turned off. The relative abundances of photoproducts depend on the UV fluence, the ice temperature, and whether pure CH3OH ice or CH3OH:CH4/CO ice mixtures are used. C2H6, CH3CHO, CH3CH2OH, CH3OCH3, HCOOCH3, HOCH2CHO and (CH2OH)2 are all detected in at least one experiment. The derived product-formation yields and their dependences on different experimental parameters, such as the initial ice composition, are used to estimate the CH3OH photodissociation branching ratios in ice and the relative diffusion barriers of the formed radicals. The experiments show that ice photochemistry in CH3OH ices is efficient enough to explain the observed abundances of complex organics around protostars and that ratios of complex molecules can be used to constrain their formation pathway.Comment: Accepted for publication in A&A. 65 pages including appendice

The c2d Spitzer spectroscopy survey of ices around low-mass young stellar objects, III: CH4

CH4 is proposed to be the starting point of a rich organic chemistry. Solid CH4 abundances have previously been determined mostly toward high mass star forming regions. Spitzer/IRS now provides a unique opportunity to probe solid CH4 toward low mass star forming regions as well. Infrared spectra from the Spitzer Space Telescope are presented to determine the solid CH4 abundance toward a large sample of low mass young stellar objects. 25 out of 52 ice sources in the $c2d$ (cores to disks) legacy have an absorption feature at 7.7 um, attributed to the bending mode of solid CH4. The solid CH4 / H2O abundances are 2-8%, except for three sources with abundances as high as 11-13%. These latter sources have relatively large uncertainties due to small total ice column densities. Toward sources with H2O column densities above 2E18 cm-2, the CH4 abundances (20 out of 25) are nearly constant at 4.7+/-1.6%. Correlation plots with solid H2O, CH3OH, CO2 and CO column densities and abundances relative to H2O reveal a closer relationship of solid CH4 with CO2 and H2O than with solid CO and CH3OH. The inferred solid CH4 abundances are consistent with models where CH4 is formed through sequential hydrogenation of C on grain surfaces. Finally the equal or higher abundances toward low mass young stellar objects compared with high mass objects and the correlation studies support this formation pathway as well, but not the two competing theories: formation from CH3OH and formation in gas phase with subsequent freeze-out.Comment: 27 pages, 7 figures, accepted by Ap

An ALMA survey of DCN/H13^{13}CN and DCO+^+/H13^{13}CO+^+ in protoplanetary disks

The deuterium enrichment of molecules is sensitive to their formation environment. Constraining patterns of deuterium chemistry in protoplanetary disks is therefore useful for probing how material is inherited or reprocessed throughout the stages of star and planet formation. We present ALMA observations at $\sim0.6"$ resolution of DCO$^+$, H$^{13}$CO$^+$, DCN, and H$^{13}$CN in the full disks around T Tauri stars AS 209 and IM Lup, the transition disks around T Tauri stars V4046 Sgr and LkCa 15, and the full disks around Herbig Ae stars MWC 480 and HD 163296. We also present ALMA observations of HCN in the IM Lup disk. DCN, DCO$^+$, and H$^{13}$CO$^+$ are detected in all disks, and H$^{13}$CN in all but the IM Lup disk. We find efficient deuterium fractionation for the sample, with estimates of disk-averaged DCO$^+$/HCO$^+$ and DCN/HCN abundance ratios ranging from $\sim0.02-0.06$ and $\sim0.005-0.08$, respectively, which is comparable to values reported for other ISM environments. The relative distributions of DCN and DCO$^+$ vary between disks, suggesting that multiple formation pathways may be needed to explain the diverse emission morphologies. In addition, gaps and rings observed in both H$^{13}$CO$^+$ and DCO$^+$ emission provide new evidence that DCO$^+$ bears a complex relationship with the location of the midplane CO snowline.Comment: 36 pages, 14 figures, updated to match figure order of published version in Ap

DeWitt Wallace Library Biennial Report 2011-2013

Summary of library activities for 2011-201

Genetic contribution to postpartum haemorrhage in Swedish population: cohort study of 466 686 births

Objective: To investigate the familial clustering of postpartum haemorrhage in the Swedish population, and to quantify the relative contributions of genetic and environmental effects. Design: Register based cohort study. Setting: Swedish population (multi-generation and medical birth registers). Main outcome measure Postpartum haemorrhage, defined as >1000 mL estimated blood loss. Participants: The first two live births to individuals in Sweden in 1997-2009 contributed to clusters representing intact couples (n=366 350 births), mothers with separate partners (n=53 292), fathers with separate partners (n=47 054), sister pairs (n=97 228), brother pairs (n=91 168), and mixed sibling pairs (n=177 944). Methods: Familial clustering was quantified through cluster specific tetrachoric correlation coefficients, and the influence of potential sharing of known risk factors was evaluated with alternating logistic regression. Relative contributions of genetic and environmental effects to the variation in liability for postpartum haemorrhage were quantified with generalised linear mixed models. Results: The overall prevalence of postpartum haemorrhage after vaginal deliveries in our sample was 4.6%. Among vaginal deliveries, 18% (95% confidence interval 9% to 26%) of the variation in postpartum haemorrhage liability was attributed to maternal genetic factors, 10% (1% to 19%) to unique maternal environment, and 11% (0% to 26%) to fetal genetic effects. Adjustment for known risk factors only partially explained estimates of familial clustering, suggesting that the observed shared genetic and environmental effects operate in part through pathways independent of known risk factors. There were similar patterns of familial clustering for both of the main subtypes examined (atony and retained placenta), though strongest for haemorrhage after retained placenta. Conclusions: There is a maternal genetic predisposition to postpartum haemorrhage, but more than half of the total variation in liability is attributable to factors that are not shared in families

Structural Heat Intercept, Insulation and Vibration Evaluation Rig (SHIIVER)

The Structural Heat Intercept, Insulation, and Vibration Evaluation Rig (SHIIVER) is a large scale cryogenic fluid management (CFM) test bed designed to scale CFM technologies for inclusion on large, in-space stages. A part of the evolvable Cryogenics (eCryo) project, SHIIVER is a technology development task that is supportive of future exploration propulsion needs. Technologies developed under the eCryo Project will play a critical role in enabling increasingly longer duration in-space missions beyond Low Earth Orbit (LEO)

Brazilian version of the Nottingham Sensory Assessment: validity, agreement and reliability

OBJETIVO: Verificar a concordância inter e intraexaminador, validade construtiva e consistência interna da versão brasileira do instrumento Nottingham Sensory Assessment para hemiparéticos após acidente vascular encefálico (AVE). MÉTODOS: O instrumento foi traduzido para língua portuguesa com base na sua versão original em Inglês por um tradutor bilíngue e, posteriormente, revertido para a língua inglesa. Vinte e um hemiparéticos foram avaliados por dois examinadores pela Avaliação Sensorial de Nottingham para pacientes pós-AVE (ASN) e pelo Protocolo de Desempenho Físico de Fugl-Meyer (FM). RESULTADOS: Foi encontrada correlação entre os instrumentos FM e ASN (0,752); excelente consistência interna da ASN (0,86); excelentes coeficientes de concordância interexaminador e intraexaminador para todos os itens da ASN, exceto temperatura e efeito teto significativo para ASN e FM. CONCLUSÃO: A versão brasileira da Nottingham Sensory Assessment cumpriu os critérios de concordância, consistência interna e validade concorrente, sendo um instrumento de rápida e fácil aplicação, podendo ser utilizada nos ambulatórios de neuroreabilitação para avaliar a função sensorial pós-AVE. O efeito teto significativo da ASN não limita seu uso, tendo em vista que, para os mesmos pacientes, o Protocolo de Fugl-Meyer também revelou efeito teto.OBJECTIVES: To investigate the inter-rater and intra-rater reliability, construct validity and internal consistency of the Brazilian version of the Nottingham Sensory Assessment for Stroke Patients (NSA). METHODS: The instrument was translated into Portuguese from its original in English by a bilingual translator and was then back-translated into English. Twenty-one hemiparetics were evaluated by two examiners using the NSA and the Fugl-Meyer Assessment (FMA) of physical performance. RESULTS: Significant correlation were found between the FMA and the NSA (r=0.752). The NSA showed excellent internal consistency (0.86), and there were acceptable inter- and intra-rater reliability for all items of the NSA, except temperature. Significant ceiling effects were found for the NSA and the FMA. CONCLUSIONS: The Brazilian version of the NSA met the criteria for agreement, internal consistency and concurrent validity. It was quick and easy to apply, and it could be used within clinical practice in neuro-rehabilitation outpatient clinics to assess sensory functions following stroke. The significant ceiling effect for the NSA did not limit its use, given that for the same patients, the FMA also showed ceiling effects