12,862 research outputs found
From mass to structure: An aromaticity index for high-resolution mass data of natural organic matter
Recent progress in Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) provided extensive molecular mass data for complex natural organic matter (NOM). Structural information can be deduced solely from the molecular masses for ions with extreme molecular element ratios, in particular low H/C ratios, which are abundant in thermally altered NOM (e.g. black carbon). In this communication we propose a general aromaticity index (AI) and two threshold values as unequivocal criteria for the existence of either aromatic (AI > 0.5) or condensed aromatic structures (AI >= 0.67) in NOM. AI can be calculated from molecular formulae which are derived from exact molecular masses of naturally occurring compounds containing C, H, O, N, S and P and is especially applicable for substances with aromatic cores and few alkylations. In order to test the validity of our model index, AI is applied to FTICRMS data of a NOM deep-water sample from the Weddell Sea (Antarctica), a fulvic acid standard and an artificial dataset of all theoretically possible molecular formulae. For graphical evaluation a ternary plot is suggested for four-dimensional data representation. The proposed aromaticity index is a step towards structural identification of NOM and the molecular identification of black carbon in the environment
Transition to High-Speed Networks — SuperJANET Experience
For the time being, trials to establish the Information Superhighway are booming. In Britain, JANET has provided wide-area computer communication, and has recently been upgraded to SuperJANET, increasing the throughput by a factor of five to 10 Mb/s, with some sites having PDH access at n Ă— 34 Mb/s. In this paper, the technological changes seen from a user perspective are addressed. A multimedia communication-based distance learning project on SuperJANET is introduced and the network performance measurements for this project are presented. These measurements suggest the employment of reservation protocol and packet scheduling. We also provide a mechanism for on-the-fly playback of continuous media
First Science Observations with SOFIA/FORCAST: 6 TO 37 micron Imaging of Orion BN/KL
The BN/KL region of the Orion Nebula is the nearest region of high mass star
formation in our galaxy. As such, it has been the subject of intense
investigation at a variety of wavelengths, which have revealed it to be
brightest in the infrared to sub-mm wavelength regime. Using the newly
commissioned SOFIA airborne telescope and its 5-40 micron camera FORCAST,
images of the entire BN/KL complex have been acquired. The 31.5 and 37.1 micron
images represent the highest resolution observations (<=4") ever obtained of
this region at these wavelengths. These observations reveal that the BN object
is not the dominant brightness source in the complex at wavelengths >31.5
microns, and that this distinction goes instead to the source IRc4. It was
determined from these images and derived dust color temperature maps that IRc4
is also likely to be self-luminous. A new source of emission has also been
identified at wavelengths >31.5 microns that coincides with the northeastern
outflow lobe from the protostellar disk associated with radio source I.Comment: 6 pages, 3 figures, accepted for publication in ApJ
Human microglial cells synthesize albumin in brain
Albumin has been implicated in Alzheimer's disease since it can bind to and transport amyloid beta, the causative agent; albumin is also a potent inhibitor of amyloid beta polymerization. In a pilot phase study of Human Brain Proteome Project, we found evidence that albumin may be synthesized in immortalized human microglial cells, human primary microglial cells, and human fetal and adult brain tissues. We also found the synthesis and secretion is enhanced upon microglial activation by Amyloid [beta]~1-42~, lipopolysaccharide treatment or human Alzheimer's brain
Prevalence of Borrelia burgdorferi, the Lyme Disease Spirochete, in Ticks and Rodents in Northeast Arkansas
Lyme disease, caused by the spirochete, Borrelia burgdorferi, has been reported from 36 of Arkansas\u27 75 counties. Ticks and wild rodents from nine northeast Arkansas counties were surveyed to determine the prevalence of Borrelia infection in potential tick vectors and reservoir host populations. In direct immunofluorescent assays with murine monoclonal antibody H5332, specific for B. burgdorferi, detected a 2.1% rate of infection for the 638 ticks surveyed and an 11.8% infectivity rate for the 102 rodents surveyed
Vitamin D levels in peanut allergic children
Background
The prevalence of peanut allergy is increasing. The reasons for this are not entirely known. A factor may be vitamin D (Vit D).
Methods
This study was performed in a referral allergist’s office in Ontario. Prospectively, all patients (\u3c18 years old) with peanut allergy who were tested for peanut specific IgE (PN IgE) also had Vit D measured. All measurements were done between December 2010 and May 2011. The Vit D measure was 25-hydroxy vitamin D. Patients were divided into three groups: deficient (less than 25 nmol/L), insufficient (25-75 nmol/L) and sufficient (75-250 nmol/L). Vit D levels were compared to PN IgE, sex, age, body mass index (BMI) and other allergies.
Results
Fifty peanut allergic patients were included. The mean Vit D level of the patients was 73.8 nmol/L and the 95% confidence interval was 69.6 - 75.7 nmol/L. One patient (2%) had deficient and thirty-one (62%) of the patients had insufficient Vit D levels. Nineteen (38%) had Vit D levels in the sufficient range. There was no correlation between Vit D levels and PN IgE or BMI. Generalized linear modeling showed that vit D levels were predicted by age and sex (p=0.04 & p=0.002, respectively).
Conclusions
Two percent of our patients had deficient Vit D levels while 62% of our patients had insufficient Vit D levels. These levels were statistically associated with age and sex. Insufficiency of Vit D may play a role in peanut allergy
An analysis of infrared emission spectra from the regions near the Galactic Center
We present consistent modelling of line and continuum IR spectra in the
region close to the Galactic center. The models account for the coupled effect
of shocks and photoionization from an external source. The results show that
the shock velocities range between 65 and 80 km/s, the pre-shock densities
between 1 cm-3 in the ISM to 200 cm-3 in the filamentary structures. The
pre-shock magnetic field increases from 5. 10^{-6} gauss in the surrounding ISM
to ~8. 10^{-5} gauss in the Arched Filaments. The stellar temperatures are
~38000 K in the Quintuplet cluster and ~27000 K in the Arches Cluster. The
ionization parameter is relatively low (<0.01) with the highest values near the
clusters, reaching a maximum >0.01 near the Arches Cluster. Depletion from the
gaseous phase of Si is found throughout the whole observed region, indicating
the presence of silicate dust. Grains including iron, are concentrated
throughout the Arched Filaments. The modelling of the continuum SED in the IR
range, indicates that a component of dust at temperatures of ~100-200 K is
present in the central region of the Galaxy. Radio emission appears to be
thermal bremsstrahlung in the E2-W1 filaments crossing strip, however a
synchrotron component is not excluded. More data are necessary to resolve this
questions.Comment: accepted for publication in the MNRA
Inside out: the interrelationships of sustainable performance metrics and its effect on business decision making: theory and practice
There has been an increasing interest in the use of decision-making models to achieve sustainability goal in recent decades. However, a systematic review of performance metrics, which are an important element of decision-making models to evaluate the outcomes regarding firm’s economic, environmental and social performance, is lacking. This study provides critical reflections on the current state of literature and industry development regarding sustainable performance metrics and offers concrete suggestions to guide future research. This study contributes to existing studies by (1) exploring the interrelationship between sustainable triple-bottom performance in the decision making process; (2) integrating corporate governance mechanism into decision making process for sustainable consideration; and (3) conducting a comparison between academic theory and industry practice regarding the performance metrics proposed and employe
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