23 research outputs found
HYPERFINE RESOLVED PURE ROTATIONAL SPECTROSCOPY OF ScN, YN, AND BaNH (X1_+): INSIGHT INTO METAL-NITROGEN BONDING
Fourier transform microwave spectroscopy coupled with a discharge-assisted laser ablation source (DALAS) has been used to record the J,=,1,,0 pure rotational transitions of ScN, ScN, YN, YN, and BaNH (X). Each species was synthesized by the reaction of the ablated metal with either NH or NH in the presence of a DC discharge. For each species hyperfine structure was resolved. In the case of ScN and YN hyperfine parameters (quadrupole and nuclear spin-rotation) for the metal and nitrogen were determined and for BaNH the nitrogen quadrupole coupling constant was measured. These hyperfine constants are interpreted to gain insight into the metal-nitrogen bonding in each species. In addition, DFT calculations were performed to assist with the assignment of each spectrum and the characterization of the metal-nitrogen bond
A Multi-Wavelength Study of Parent Volatile Abundances in Comet C/2006 M4 (SWAN)
Volatile organic emissions were detected post-perihelion in the long period comet C/2006 M4 (SWAN) in October and November 2006. Our study combines target-of-opportunity, observations using the infrared Cryogenic Echelle Spectrometer (CSHELL) at the NASA-IRTF 3-m telescope, and millimeter wavelength observations using the Arizona Radio Observatory (ARO) 12-m telescope. Five parent volatiles were measured with CSHELL (H2O, CO, CH3OH, CH4, and C2H6), and two additional species (HCN and CS) were measured with the ARID 12-m. These revealed highly depleted CO and somewhat enriched CH3OH compared with abundances observed in the dominant group of long-period (Oort cloud) comets in our sample and similar to those observed recently in Comet 8P/Tuttle. This may indicate highly efficient H-atom addition to CO at very low temperature (approx.10-20 K) on the surfaces of interstellar (pre-cometary) grains. Comet C12006 M4 had nearly "normal" C2H6, and CH4, suggesting a processing history similar to that experienced by the dominant group. When compared with estimated water production at the time of the millimeter observations, HCN was slightly depleted compared with the normal abundance in comets based on 1R observations but was consistent with the majority of values from the millimeter. The ratio CS/HCN in C/2006 M4 was within the range measured in ten comets at millimeter wavelengths. The higher apparent H-atom conversion efficiency compared with most comets may indicate that the icy grains incorporated into C/2006 M4 were exposed to higher H-atom densities, or alternatively to similar densities but for a longer period of time
A chirped-pulse Fourier-transform microwave/pulsed uniform flow spectrometer. I. The low-temperature flow system
We report the development of a new instrument that combines chirped-pulse microwave spectroscopy with a pulsed uniform supersonic flow. This combination promises a nearly universal detection method that can deliver isomer and conformer specific, quantitative detection and spectroscopic characterization of unstable reaction products and intermediates, product vibrational distributions, and molecular excited states. This first paper in a series of two presents a new pulsed-flow design, at the heart of which is a fast, high-throughput pulsed valve driven by a piezoelectric stack actuator. Uniform flows at temperatures as low as 20 K were readily achieved with only modest pumping requirements, as demonstrated by impact pressure measurements and pure rotational spectroscopy. The proposed technique will be suitable for application in diverse fields including fundamental studies in spectroscopy, kinetics, and reaction dynamics.National Science Foundation (U.S.) (Award MRI-ID 1126380
The relationships between golf and health:A scoping review
OBJECTIVE: To assess the relationships between golf and health. DESIGN: Scoping review. DATA SOURCES: Published and unpublished reports of any age or language, identified by searching electronic databases, platforms, reference lists, websites and from consulting experts. REVIEW METHODS: A 3-step search strategy identified relevant published primary and secondary studies as well as grey literature. Identified studies were screened for final inclusion. Data were extracted using a standardised tool, to form (1) a descriptive analysis and (2) a thematic summary. RESULTS AND DISCUSSION: 4944 records were identified with an initial search. 301 studies met criteria for the scoping review. Golf can provide moderate intensity physical activity and is associated with physical health benefits that include improved cardiovascular, respiratory and metabolic profiles, and improved wellness. There is limited evidence related to golf and mental health. The incidence of golfing injury is moderate, with back injuries the most frequent. Accidental head injuries are rare, but can have serious consequences. CONCLUSIONS: Practitioners and policymakers can be encouraged to support more people to play golf, due to associated improved physical health and mental well-being, and a potential contribution to increased life expectancy. Injuries and illnesses associated with golf have been identified, and risk reduction strategies are warranted. Further research priorities include systematic reviews to further explore the cause and effect nature of the relationships described. Research characterising golf's contribution to muscular strengthening, balance and falls prevention as well as further assessing the associations and effects between golf and mental health are also indicated
Gathering Global Perspectives to Establish the Research Priorities and Minimum Data Sets for Degenerative Cervical Myelopathy:Sampling Strategy of the First Round Consensus Surveys of AO Spine RECODE-DCM
STUDY DESIGN: Survey.INTRODUCTION: AO Spine Research Objectives and Common Data Elements for Degenerative Cervical Myelopathy (AO Spine RECODE-DCM) is an international initiative that aims to accelerate knowledge discovery and improve outcomes by developing a consensus framework for research. This includes defining the top research priorities, an index term and a minimum data set (core outcome set and core data elements set - core outcome set (COS)/core data elements (CDE)).OBJECTIVE: To describe how perspectives were gathered and report the detailed sampling characteristics.METHODS: A two-stage, electronic survey was used to gather and seek initial consensus. Perspectives were sought from spinal surgeons, other healthcare professionals and people with degenerative cervical myelopathy (DCM). Participants were allocated to one of two parallel streams: (1) priority setting or (2) minimum dataset. An email campaign was developed to advertise the survey to relevant global stakeholder individuals and organisations. People with DCM were recruited using the international DCM charity Myelopathy.org and its social media channels. A network of global partners was recruited to act as project ambassadors. Data from Google Analytics, MailChimp and Calibrum helped optimise survey dissemination.RESULTS: Survey engagement was high amongst the three stakeholder groups: 208 people with DCM, 389 spinal surgeons and 157 other healthcare professionals. Individuals from 76 different countries participated; the United States, United Kingdom and Canada were the most common countries of participants.CONCLUSION: AO Spine RECODE-DCM recruited a diverse and sufficient number of participants for an international PSP and COS/CDE process. Whilst PSP and COS/CDE have been undertaken in other fields, to our knowledge, this is the first time they have been combined in one process.</p
A large genome-wide association study of age-related macular degeneration highlights contributions of rare and common variants.
This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/ng.3448Advanced age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, with limited therapeutic options. Here we report on a study of >12 million variants, including 163,714 directly genotyped, mostly rare, protein-altering variants. Analyzing 16,144 patients and 17,832 controls, we identify 52 independently associated common and rare variants (P < 5 Ă 10(-8)) distributed across 34 loci. Although wet and dry AMD subtypes exhibit predominantly shared genetics, we identify the first genetic association signal specific to wet AMD, near MMP9 (difference P value = 4.1 Ă 10(-10)). Very rare coding variants (frequency <0.1%) in CFH, CFI and TIMP3 suggest causal roles for these genes, as does a splice variant in SLC16A8. Our results support the hypothesis that rare coding variants can pinpoint causal genes within known genetic loci and illustrate that applying the approach systematically to detect new loci requires extremely large sample sizes.We thank all participants of all the studies included for enabling this research by their participation in these studies. Computer resources for this project have been provided by the high-performance computing centers of the University of Michigan and the University of Regensburg. Group-specific acknowledgments can be found in the Supplementary Note. The Center for Inherited Diseases Research (CIDR) Program contract number is HHSN268201200008I. This and the main consortium work were predominantly funded by 1X01HG006934-01 to G.R.A. and R01 EY022310 to J.L.H
Laboratory spectroscopy of astrophysically relevant carbon species
Carbon is one of the most common elements in the solar system, with a fractional abundance of 10-4 relative to hydrogen. Thus, it is not surprising that over 100 carbon-bearing species have been definitively detected in the interstellar medium via their rotational, infrared, and/or electronic transitions. In order to identify these species, laboratory spectra are needed for comparison to astronomical data. Challenges arise when obtaining laboratory spectra due to the instability of many of these molecules. Over the years, sensitive instrumentation and better techniques for producing these species in situ have been developed to achieve this goal. The use of complementary spectroscopic methods, such as matrix isolation, cavity ringdown, resonance enhanced multiphoton ionization, and ion trapping have led to the identification of several new carbon species at optical and ultraviolet wavelengths. Laboratory spectra have been compared to astronomical data in order to gain further insight into interstellar chemistry. In particular, attempts have been made to identify the carriers of the diffuse interstellar bands, however, with little success. These results are discussed in the following review
Product Branching in the Low Temperature Reaction of CN with Propyne by Chirped-Pulse Microwave Spectroscopy in a Uniform Supersonic Flow
International audienc
Chirped-Pulse in Uniform Flow
International audienceThe synergy between laboratory measurements, theoretical advances, and modeling of chemical networks has led to considerable progress in our understanding of astrophysical environments. However, experimentally measured reaction rates generally leave product identity and branching ratios unknown. This limitation arises from experimental challenges inherent in quantitative detection of the full range of products of a given reaction, especially for large polyatomic systems. To address this problem, we have developed a new approach that uses broadband microwave pulses (> 10 GHz) to probe the reaction products thermalized at low temperatures (~ 20 K) in a uniform supersonic flow (Chirped-Pulse in Uniform Flow, C-PUF). This technique provides clear and quantifiable spectroscopic signatures for all products with a dipole moment. I will first illustrate the performance of our approach and discuss a number of challenges related to the collisional environment in the flow. A detailed study of the CN + C3H4 reaction in the spectral range [60-90] GHz will then be presented. Finally, I will focus on the potential of C-PUF for astrochemistry thanks to an unprecedented overlap with the frequency ranges of current radio telescopes such as ALMA and NOEMA.La synergie entre les mesures de laboratoire, les avancĂ©es thĂ©oriques, et la modĂ©lisation des rĂ©seaux chimiques a conduit Ă des progrĂšs considĂ©rables de notre comprĂ©hension de la chimie dans les milieux astrophysiques. Cependant, les taux de rĂ©action mesurĂ©s expĂ©rimentalement laissent gĂ©nĂ©ralement l'identitĂ© des produits et leurs rapports de branchement inconnus. Cette limitation provient de dĂ©fis expĂ©rimentaux inhĂ©rents Ă la dĂ©tection quantitative de la gamme complĂšte de produits d'une rĂ©action donnĂ©e, en particulier pour les systĂšmes polyatomiques de grande taille. Pour rĂ©pondre Ă cette problĂ©matique, nous avons dĂ©veloppĂ© une nouvelle approche qui utilise des impulsions micro-ondes large-bande (>10 GHz) pour sonder les produits de rĂ©action thermalisĂ©s Ă basses tempĂ©ratures (~ 20 K) dans un Ă©coulement supersonique uniforme (Chirped-Pulse in Uniform Flow, C-PUF). Cette technique fournit des signatures spectroscopiques claires et quantifiables pour tous les produits possĂ©dant un moment dipolaire. Je vais d'abord illustrer ces performances et discuter un certain nombre de dĂ©fis liĂ©s Ă l'environnement collisionnel dans l'Ă©coulement. Une Ă©tude dĂ©taillĂ©e de la rĂ©action CN + C3H4 dans la gamme spectrale [60-90] GHz sera ensuite prĂ©sentĂ©e. Enfin, lâaccent sera mis sur le fort potentiel de C-PUF pour lâastrochimie grĂące Ă un recouvrement inĂ©dit avec les domaines de frĂ©quences des radiotĂ©lescopes actuels tels que NOEMA et ALMA