1,548 research outputs found
An operative gamma camera for sentinel lymph node procedure in case of breast cancer
Large field of view gamma cameras are widely used to perform lymphoscintigraphy in the sentinel lymph nodes (SLN) procedure in case of breast cancer. However, they are not specified for this application and their sizes do not enable their use in the operative room to control the excision of the all SLN. We present the results obtained with a prototype of a new mini gamma camera developed especially for the operative lymphoscintigraphy of the axillary area in case of breast cancer. This prototype is composed of 10 mm thick parallel lead collimator, a 2 mm thick GSO:Ce inorganic scintillating crystal from Hitachi and a Hamamatsu H8500 flat panel multianode (64 channels) photomultiplier tube (MAPMT) equipped with a dedicated electronics. Its actual field of view is 50 Ă 50mm2. The gamma interaction position in the GSO scintillating plate is obtained by calculating the center of gravity of the fired MAPMT channels. The measurements performed with this prototype demonstrate the usefulness of this mini gamma camera for the pre, per and post-operative identification of SLN's and how its complementary role with an intraoperative handheld gamma probe enables to improve the efficiency of this practice. A 100 Ă 100mm2 field of view camera designated to cover the entire axillary area is under investigation
Do SiC grains in Orgueil differ from those in Murchison?
Studies of individual presolar SiC grains have shown that most are enriched in Si-29, Si-30, and C-13, and depleted in N-15, compared to solar-system abundances and that many have large excesses of Mg-26, most plausibly from in situ decay of Al-26. Stone et al., observed that Si from a family of platy SiC grains define a linear array on a 3-isotope plot that does not pass through normal solar-system Si. In contrast, Si-isotope data from over 100 3-4 micron SiC grains from Murchison from an elongate ellipse enclosing the Stone et al. linear array but also including 'normal' solar-system Si. To investigate whether this difference in Si isotopes indicates different populations of SiC in the two meteorites and to improve the characterization of Orgueil SiC, we used the PANURGE ion microprobe to measure Si, C, N, and Mg isotopes and Al and Na concentrations in a suite of 2-5 micron SiC grains from a new sample of Orgueil
Determining the Elemental and Isotopic Composition of the preSolar Nebula from Genesis Data Analysis: The Case of Oxygen
We compare element and isotopic fractionations measured in solar wind samples
collected by NASA's Genesis mission with those predicted from models
incorporating both the ponderomotive force in the chromosphere and conservation
of the first adiabatic invariant in the low corona. Generally good agreement is
found, suggesting that these factors are consistent with the process of solar
wind fractionation. Based on bulk wind measurements, we also consider in more
detail the isotopic and elemental abundances of O. We find mild support for an
O abundance in the range 8.75 - 8.83, with a value as low as 8.69 disfavored. A
stronger conclusion must await solar wind regime specific measurements from the
Genesis samples.Comment: 6 pages, accepted by Astrophysical Journal Letter
Reaction of Q to thermal metamorphism in parent bodies: Experimental simulation
Planetary noble gases in chondrites are concentrated in an unidentified carrier phase, called âQ.â Phase Q oxidized at relatively low temperature in pure oxygen is a very minor part of insoluble organic matter (IOM), but has not been separated in a pure form. Highâpressure (HP) experiments have been used to test the effects of thermal metamorphism on IOM from the Orgueil (CI1) meteorite, at conditions up to 10 GPa and 700 °C. The effect of the treatment on carbon structural order was characterized by Raman spectroscopy of the carbon D and G bands. The Raman results show that the IOM becomes progressively more graphiteâlike with increasing intensity and duration of the HP treatment. The carbon structural transformations are accompanied by an increase in the release temperatures for IOM carbon and Ar during stepped combustion (the former to a greater extent than the latter for the most HP treated sample) when compared with the original untreated Orgueil (CI1) sample. The Ar/C ratio also appears to vary in response to HP treatment. Since Ar is a part of Q, its release temperature corresponds to that for Q oxidation. Thus, the structural transformations of Q and IOM upon HP treatment are not equal. These results correspond to observations of thermal metamorphism in the meteorite parent bodies, in particular those of type 4 enstatite chondrites, e.g., Indarch (EH4), where graphitized IOM oxidized at significantly higher temperatures than Q (Verchovsky et al. 2002). Our findings imply that Q is less graphitized than most of the macromolecular carbonaceous material present during parent body metamorphism and is thus a carbonaceous phase distinct from other meteoritic IOM
Wikipedia as an encyclopaedia of life
In his 2003 essay E O Wilson outlined his vision for an “encyclopaedia of life” comprising “an electronic page for each species of organism on Earth”, each page containing “the scientific name of the species, a pictorial or genomic presentation of the primary type specimen on which its name is based, and a summary of its diagnostic traits.” Although the “quiet revolution” in biodiversity informatics has generated numerous online resources, including some directly inspired by Wilson's essay (e.g., "http://ispecies.org":http://ispecies.org, "http://www.eol.org":http://www.eol.org), we are still some way from the goal of having available online all relevant information about a species, such as its taxonomy, evolutionary history, genomics, morphology, ecology, and behaviour. While the biodiversity community has been developing a plethora of databases, some with overlapping goals and duplicated content, Wikipedia has been slowly growing to the point where it now has over 100,000 pages on biological taxa. My goal in this essay is to explore the idea that, largely independent of the efforts of biodiversity informatics and well-funded international efforts, Wikipedia ("http://en.wikipedia.org/wiki/Main_Page":http://en.wikipedia.org/wiki/Main_Page) has emerged as potentially the best platform for fulfilling E O Wilson’s vision
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Global glacier volume projections under high-end climate change scenarios
The Paris agreement aims to hold global warming to well below 2°C and to pursue efforts to limit it to 1.5°C relative to the pre-industrial period. Recent estimates based on population growth and intended carbon emissions from participant countries, suggest global warming may exceed this ambitious target. Here we present glacier volume projections for the end of this century, under a range of high-end climate change scenarios, defined as exceeding +2°C global average warming relative to the preindustrial period. Glacier volume is modelled by developing an elevation-dependent mass balance model for the Joint UK Land Environmental Simulator (JULES). To do this, we modify JULES to include glaciated and un-glaciated surfaces that can exist at multiple heights within a single grid-box. Present day mass balance is calibrated by tuning albedo, wind speed, precipitation and temperature lapse rates to obtain the best agreement with observed mass balance profiles. JULES is forced with an ensemble of six Coupled Model Intercomparison Project Phase 5 (CMIP5) models which were downscaled using the high resolution HadGEM3-A atmosphere only global climate model. The ensemble mean volume loss at the end of the century plus/minus one standard deviation is, minus;64±5% for all glaciers excluding those on the peripheral of the Antarctic ice sheet. The uncertainty in the multi-model mean is rather small and caused by the sensitivity of HadGEM3-A to the boundary conditions supplied by the CMIP5 models. The regions which lose more than 75% of their initial volume by the end of the century are; Alaska, Western Canada and US, Iceland, Scandinavia, Russian Arctic, Central Europe, Caucasus, High Mountain Asia, Low Latitudes, Southern Andes and New Zealand. The ensemble mean ice loss expressed in sea-level equivalent contribution is 215.2±21.3mm. The largest contributors to sea level rise are Alaska (44.6±1.1mm), Arctic Canada North and South (34.9±3.0mm), Russian Arctic (33.3±4.8mm), Greenland (20.1±4.4), High Mountain Asia (combined Central Asia, South Asia East and West), (18.0±0.8mm), Southern Andes (14.4±0.1mm) and Svalbard (17.0±4.6mm). Including parametric uncertainty in the calibrated mass balance parameters, gives an upper bound global volume loss of 247.3mm, sea-level equivalent by the end of the century. Such large ice losses will have inevitable consequences for sea-level rise and for water supply in glacier-fed river systems
Modeling axial spinal segments of the salamander central pattern generator for locomotion
Poster presentationInternational audiencen.
XTE J1739-302 as a Supergiant Fast X-ray Transient
XTE J1739-302 is a transient X-ray source with unusually short outbursts,
lasting on the order of hours. Here we give a summary of X-ray observations we
have made of this object in outburst with the Rossi X-ray Timing Explorer
(RXTE) and at a low level of activity with the Chandra X-ray Observatory, as
well as observations made by other groups. Visible and infrared spectroscopy of
the mass donor of XTE J1739-302 are presented in a companion paper. The X-ray
spectrum is hard both at low levels and in outburst, but somewhat variable, and
there is strong variability in the absorption column from one outburst to
another. Although no pulsation has been observed, the outburst data from
multiple observatories show a characteristic timescale for variability on the
order of 1500-2000 s. The Chandra localization (right ascension 17h 39m 11.58s,
declination -30o 20' 37.6'', J2000) shows that despite being located less than
2 degrees from the Galactic Center and highly absorbed, XTE J1739-302 is
actually a foreground object with a bright optical counterpart. The combination
of a very short outburst timescale and a supergiant companion is shared with
several other recently-discovered systems, forming a class we designate as
Supergiant Fast X-ray Transients (SFXTs). Three persistently bright X-ray
binaries with similar supergiant companions have also produced extremely short,
bright outbursts: Cyg X-1, Vela X-1, and 1E 1145.1-6141.Comment: 16 pages, 7 figures, 2 tables, in press in The Astrophysical Journal;
see also the companion paper by Negueruela et a
The NY-Ă lesund TurbulencE Fiber Optic eXperiment (NYTEFOX): investigating the Arctic boundary layer, Svalbard
The NY-Ă
lesund TurbulencE Fiber Optic eXperiment (NYTEFOX) was a field experiment at the
Ny-Ă
lesund Arctic site (78.9⊠N, 11.9⊠E) and yielded a unique meteorological data set. These data describe the
distribution of heat, airflows, and exchange in the Arctic boundary layer for a period of 14 d from 26 February
to 10 March 2020. NYTEFOX is the first field experiment to investigate the heterogeneity of airflow and its
transport of temperature, wind, and kinetic energy in the Arctic environment using the fiber-optic distributed
sensing (FODS) technique for horizontal and vertical observations. FODS air temperature and wind speed were
observed at a spatial resolution of 0.127 m and a temporal resolution of 9 s along a 700 m horizontal array at
1 m above ground level (a.g.l.) and along three 7 m vertical profiles. Ancillary data were collected from three
sonic anemometers and an acoustic profiler (minisodar; sodar is an acronym for âsound detection and rangingâ)
yielding turbulent flow statistics and vertical profiles in the lowest 300 m a.g.l., respectively. The observations
from this field campaign are publicly available on Zenodo (https://doi.org/10.5281/zenodo.4756836, Huss et al.,
2021) and supplement the meteorological data set operationally collected by the Baseline Surface Radiation
Network (BSRN) at Ny-Ă
lesund, Svalbard
Correlations Between Clinical Trial Outcomes Based on Symptoms, Functional Impairments, and Quality of Life in Children and Adolescents With ADHD
OBJECTIVE: To assess relationships between treatment-associated changes in measures of ADHD symptoms, functional impairments, and health-related quality of life in children and adolescents with ADHD. METHOD: Pearson correlation coefficients were calculated post hoc for changes from baseline to endpoint in outcomes of one randomized, placebo- and active-controlled trial of lisdexamfetamine (osmotic-release methylphenidate reference) and one of guanfacine extended-release (atomoxetine reference). RESULTS: Changes in ADHD Rating Scale IV (ADHD-RS-IV) total score generally correlated moderately with changes in Child Health and Illness Profile-Child Edition: Parent Report Form (CHIP-CE:PRF) Achievement and Risk Avoidance ( r â .4), but weakly with Resilience, Satisfaction, and Comfort ( r â .2); and moderately with Weiss Functional Impairment Rating Scale-Parent (WFIRS-P) total score ( r â .5). CHIP-CE: PRF Achievement and Risk Avoidance correlated moderately to strongly with WFIRS-P total score ( r â .6). CONCLUSION: The ADHD-RS-IV, CHIP-CE:PRF, and WFIRS-P capture distinct but interconnected aspects of treatment response in individuals with ADHD
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