2,274 research outputs found

    Coverage and density of a low power, low data rate, spread spectrum wireless sensor network for agricultural monitoring

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    A physical layer specification for a low power, low complexity, low data rate sensor network suitable for agricultural monitoring is investigated. Code division multiple access (CDMA) with high processing gain is used to facilitate transmission powers which comply with the Ultra Wide Band (UWB) spectral mask, and this permits physically small nodes with limited energy storage capacity. The interference arising from each node is calculated, and it is shown that for the investigated scenario and specification, an aggregate data rate of 2 bytes per minute and a node population of approximately 1000 can be supported at distances up to a few kilometres from the central node, with less than 0.2% chance of failure due to multiple access interference

    Differential effects of MDMA and methylphenidate on social cognition

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    Social cognition is important in everyday-life social interactions. The social cognitive effects of 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') and methylphenidate (both used for neuroenhancement and as party drugs) are largely unknown. We investigated the acute effects of MDMA (75 mg), methylphenidate (40 mg) and placebo using the Facial Emotion Recognition Task, Multifaceted Empathy Test, Movie for the Assessment of Social Cognition, Social Value Orientation Test and the Moral Judgment Task in a cross-over study in 30 healthy subjects. Additionally, subjective, autonomic, pharmacokinetic, endocrine and adverse drug effects were measured. MDMA enhanced emotional empathy for positive emotionally charged situations in the MET and tended to reduce the recognition of sad faces in the Facial Emotion Recognition Task. MDMA had no effects on cognitive empathy in the Multifaceted Empathy Test or social cognitive inferences in the Movie for the Assessment of Social Cognition. MDMA produced subjective 'empathogenic' effects, such as drug liking, closeness to others, openness and trust. In contrast, methylphenidate lacked such subjective effects and did not alter emotional processing, empathy or mental perspective-taking. MDMA but not methylphenidate increased the plasma levels of oxytocin and prolactin. None of the drugs influenced moral judgment. Effects on emotion recognition and emotional empathy were evident at a low dose of MDMA and likely contribute to the popularity of the drug

    A Direct Measurement of the Total Gas Column Density in Orion KL

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    The large number of high-J lines of C^(18)O available via the Herschel Space Observatory provide an unprecedented ability to model the total CO column density in hot cores. Using the emission from all the observed lines (up to J = 15-14), we sum the column densities in each individual level to obtain the total column after correcting for the population in the unobserved states. With additional knowledge of source size, V_(LSR), and line width, and both local thermodynamic equilibrium (LTE) and non-LTE modeling, we have determined the total C^(18)O column densities in the Extended Ridge, Outflow/Plateau, Compact Ridge, and Hot Core components of Orion KL to be 1.4 × 10^(16) cm^(–2), 3.5 × 10^(16) cm^(–2), 2.2 × 10^(16) cm^(–2), and 6.2 × 10^(16) cm^(–2), respectively. We also find that the C^(18)O/C^(17)O abundance ratio varies from 1.7 in the Outflow/Plateau, 2.3 in the Extended Ridge, 3.0 in the Hot Core, and to 4.1 in the Compact Ridge. This is in agreement with models in which regions with higher ultraviolet radiation fields selectively dissociate C^(17)O, although care must be taken when interpreting these numbers due to the size of the uncertainties in the C^(18)O/C^(17)O abundance ratio

    Herschel observations of EXtra-Ordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL II. Chemical Implications

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    We present chemical implications arising from spectral models fit to the Herschel/HIFI spectral survey toward the Orion Kleinmann-Low nebula (Orion KL). We focus our discussion on the eight complex organics detected within the HIFI survey utilizing a novel technique to identify those molecules emitting in the hottest gas. In particular, we find the complex nitrogen bearing species CH3_{3}CN, C2_{2}H3_{3}CN, C2_{2}H5_{5}CN, and NH2_{2}CHO systematically trace hotter gas than the oxygen bearing organics CH3_{3}OH, C2_{2}H5_{5}OH, CH3_{3}OCH3_{3}, and CH3_{3}OCHO, which do not contain nitrogen. If these complex species form predominantly on grain surfaces, this may indicate N-bearing organics are more difficult to remove from grain surfaces than O-bearing species. Another possibility is that hot (Tkin_{\rm kin}\sim300 K) gas phase chemistry naturally produces higher complex cyanide abundances while suppressing the formation of O-bearing complex organics. We compare our derived rotation temperatures and molecular abundances to chemical models, which include gas-phase and grain surface pathways. Abundances for a majority of the detected complex organics can be reproduced over timescales \gtrsim 105^{5} years, with several species being under predicted by less than 3σ\sigma. Derived rotation temperatures for most organics, furthermore, agree reasonably well with the predicted temperatures at peak abundance. We also find that sulfur bearing molecules which also contain oxygen (i.e. SO, SO2_{2}, and OCS) tend to probe the hottest gas toward Orion KL indicating the formation pathways for these species are most efficient at high temperatures.Comment: 31 pages, 6 figures, 1 Table, accepted to the Astrophysical Journa

    A combined IRAM and Herschel/HIFI study of cyano(di)acetylene in Orion KL: tentative detection of DC3N

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    We present a study of cyanoacetylene (HC3N) and cyanodiacetylene (HC5N) in Orion KL, through observations from two line surveys performed with the IRAM 30m telescope and the HIFI instrument on board the Herschel telescope. The frequency ranges covered are 80-280 GHz and 480-1906 GHz. We model the observed lines of HC3N, HC5N, their isotopologues (including DC3N), and vibrational modes, using a non-LTE radiative transfer code. To investigate the chemical origin of HC3N and DC3N in Orion KL, we use a time-dependent chemical model. We detect 40 lines of the ground state of HC3N and 68 lines of its 13C isotopologues. We also detect 297 lines of six vibrational modes of this molecule (nu_7, 2nu_7, 3nu_7, nu_6, nu_5, and nu_6+nu_7) and 35 rotational lines of the ground state of HC5N. We report the first tentative detection of DC3N in a giant molecular cloud with a DC3N/HC3N abundance ratio of 0.015. We provide column densities and isotopic and molecular abundances. We also perform a 2x2" map around Orion IRc2 and we present maps of HC3N lines and maps of lines of the HC3N vibrational modes nu_6 and nu_7. In addition, a comparison of our results for HC3N with those in other clouds allows us to derive correlations between the column density, the FWHM, the mass, and the luminosity of the clouds. The high column densities of HC3N obtained in the hot core, make this molecule an excellent tracer of hot and dense gas. In addition, the large frequency range covered reveals the need to consider a temperature and density gradient in the hot core in order to obtain better line fits. The high D/H ratio (comparable to that obtained in cold clouds) that we derive suggests a deuterium enrichment. Our chemical models indicate that the possible deuterated HC3N present in Orion KL is formed during the gas-phase. This fact provides new hints concerning the processes leading to deuteration.Comment: 50 pages, 33 figures, 13 tables. Accepted for publication in A&

    Rare manifestation of a c.290 C\u3eT, p.Gly97Glu VCP mutation

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    Introduction. The valosin-containing protein (VCP) regulates several distinct cellular processes. Consistent with this, VCP mutations manifest variable clinical phenotypes among and within families and are a diagnostic challenge. Methods. A 60-year-old man who played ice hockey into his 50’s was evaluated by electrodiagnostics, muscle biopsy, and molecular genetics. Results. With long-standing pes cavus and toe walking, our patient developed progressive weakness, cramps, memory loss, and paresthesias at age 52. An axonal sensorimotor neuropathy was found upon repeated testing at age 58. Neuropathic histopathology was present in the quadriceps, and exome sequencing revealed the VCP mutation c.290 C>T, p.Gly97Glu. Conclusions. Our patient reflects the clinical heterogeneity of VCP mutations, as his neurological localization is a spectrum between a lower motor neuron disorder and a hereditary axonal peripheral neuropathy such as CMT2. Our case demonstrates a rare manifestation of the c.290 C>T, pGly97Glu VCP mutation

    Think Pink! a Pink Sticker Alert System for Women with Psychological Distress or Vulnerability During Pregnancy

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    The importance of good clinical communication to women during pregnancy and birth is clear. Poor communication in labour is associated with general dissatisfaction, more complaints and a range of perinatal mental health problems including posttraumatic stress disorder (PTSD) and postnatal depression. To communicate effectively, maternity staff needs information about which women are vulnerable and require extra support. To address this, we implemented and evaluated a pink sticker communication system to alert midwifery and obstetric staff to potential psychological difficulties experienced by some women. Evaluation showed this system was viewed positively by women and midwifery staff. Audit of referrals to the perinatal psychology service during this period suggests no woman with a pink sticker developed birth trauma as a direct result of perceived poor care. In addition, the proportion of referrals to perinatal psychology for birth trauma significantly reduced during this period

    Constraining the mass of the GRB 030329 progenitor

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    The long-duration gamma-ray burst (GRB) 030329, associated with supernova (SN) 2003dh, occurred inside a star-forming dwarf galaxy at redshift z=0.1685z=0.1685. The low redshift, and a rich set of archival Hubble Space Telescope (HST) images, makes this GRB well-suited for a detailed study of the stellar population in the immediate vicinity of the explosion. Since the lifetime of a star is directly tied to its mass, the age of the stellar population can be used to put constraints on the GRB and SN progenitor mass. From the HST images we extract the colours of the precise site from which the GRB originated, and find that the colours are significantly different from those of the overall host galaxy and the surrounding starburst environment. We have used spectral evolutionary models, including nebular emission, to carefully constrain the age of the stellar population, and hence the progenitor, at the very explosion site. For instantaneous burst models we find that a population age of 5 Myr best matches the data, suggesting a very massive (M > 50 M_sun) star as the progenitor, with an upper limit of 8 Myr (M > 25 M_sun). For more extended star formation scenarios, the inferred progenitor age is in most cases still very young (age 25 M_sun), with an upper limit of 20 Myr (M > 12 M_sun). These age estimates are an order of magnitude lower than the ages inferred from the overall host galaxy colours, indicating that progenitor mass estimates based on data for spatially unresolved GRB host galaxies will in general be of limited use. Our results are consistent with the collapsar scenario.Comment: Accepted to MNRA

    HERSCHEL OBSERVATIONS OF EXTRA-ORDINARY SOURCES: H2S AS A PROBE OF DENSE GAS AND POSSIBLY HIDDEN LUMINOSITY TOWARD THE ORION KL HOT CORE

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    We present Herschel/HIFI observations of the light hydride H2S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the Herschel Observations of EXtra-Ordinary Sources GT (guaranteed time) key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H2 32S, H2 34S, and H2 33S, respectively. We only analyze emission from the so-called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H2S follow straight lines given the uncertainties and yield T rot = 141 ± 12 K. This indicates H2S is in local thermodynamic equilibrium and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (E up gsim 1000 K) are likely populated primarily by radiation pumping. We derive a column density, N tot(H2 32S) = 9.5 ± 1.9 × 1017 cm–2, gas kinetic temperature, T kin = 120±1013\pm ^{13}_{10} K, and constrain the H2 volume density, nH2n_{\rm H_2} gsim 9 × 10 7 cm–3, for the H2S emitting gas. These results point to an H2S origin in markedly dense, heavily embedded gas, possibly in close proximity to a hidden self-luminous source (or sources), which are conceivably responsible for Orion KL's high luminosity. We also derive an H2S ortho/para ratio of 1.7 ± 0.8 and set an upper limit for HDS/H2S of <4.9 × 10 –3
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