605 research outputs found

    Feasibility of ASD AgriSpec analysis to indicate mineralogy of a potential shale gas reservoir from West Lancashire, UK

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    Mudrocks rich in organic matter present an attractive exploration target for unconventional gas and oil. The mid-Carboniferous Bowland Shale is considered the principal accumulation of gas-prone shales in the UK. One risk with exploitation of shales is that the rocks may exhibit ductile behaviour and not respond well to hydraulic stimulation programmes. The brittle behaviour of the rock is influenced by mineralogical composition. Approximately 15 m of core from the Bowland Shale, has been used to test the feasibility of using Near Infra-Red (NIR) Spectrometry to characterise the mineralogy of the shale, and compare to analysis using standard XRD techniques

    Ice shelf history determined from deformation styles in surface debris

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    AbstractThis paper presents InSAR-derived ice shelf velocities and observations of surface debris deformation on the McMurdo Ice Shelf (MIS). Ice shelf velocities show that the MIS has a low surface velocity, with debris-laden parts of the ice shelf in the area known as the ‘swirls’ averaging speeds of c. 3 m a-1 increasing to c. 16 m a-1 at the ice front. Analysis of the fold patterns within moraine ridges on the ice surface reveals a deformational history inconsistent with the present velocity measurements. Polyphase, isoclinal folding within moraine ridges at the surface are interpreted to have formed through intense deformation by past ice flow in a NNW orientation. The velocities and styles of deformation indicate that the majority of debris on the ice shelf was originally transported into the area by a large and dynamic ice sheet/ice shelf system entirely different to that of the present configuration. Although the age of this event is unknown, it is possible that this debris has been exposed on the surface of the ice shelf since the last glacial maximum.</jats:p

    Conformational Studies of Gram-Negative Bacterial Quorum Sensing Acyl Homoserine Lactone (AHL) Molecules: the Importance of the n→* Interaction

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    A 1H NMR study shows the presence of intermolecular hydrogen bonds for AHLs in CDCl3 solution. A detailed computational study of the structure of AHLs and the relative stability between the extended conformations (X) and those showing n→p* interactions (np) have been carried out by means of DFT calculations. Solvent effects have been shown to be very important when stabilising np conformations, particularly with polar solvents. This was shown by the shortening of C···O intramolecular distances and the increase in the relative energies favouring the np conformation with the dielectric constant of the solvent. The charge transfer between the O donor and the acceptor carbonyl group, assessed by second order perturbation energies, E(2), also shows an increase in the E(2) values with the dielectric constant of the solvent

    Conformational Studies of Gram-Negative Bacterial Quorum Sensing 3-oxo N-acyl Homoserine Lactone Molecules

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    In their 1H NMR spectra in CDCl3 3-oxo-N-acyl homoserine lactones (OHLs) show significant downfield chemical shifts of the amide N-H proton when compared to the parent N-acyl homoserine lactones (AHLs). NMR spectroscopic and DFT calculation studies have shown that this is most likely due to the presence of a stabilising intramolecular H-bond from the N-H to the 3-oxo group. The 1H NMR spectra also show evidence for the enol tautomers and that the amount of enol present for a range of OHLs is 4.1-4.5% in CDCl3 and 6.5-7.2% in CD3CN. In contrast, DFT calculations show that the lowest energy enol tautomer and the keto tautomer are of equal energy in the gas phase, but that the keto tautomer is more stable in chloroform, acetonitrile and water solution. The calculations also show that there is no evidence for any n→p* or C5 H-bonding interactions being present in either the lowest energy keto or enol tautomer of the OHLs in solution or the gas phase, which is in contrast to the reported solid-state structure

    Conformational studies of Gram-negative bacterial quorum sensing acyl homoserine lactone (AHL) molecules: The importance of the n → π* interaction

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    A 1H NMR study shows the presence of intermolecular hydrogen bonds for AHLs in CDCl3 solution. A detailed computational study of the structure of AHLs and the relative stability between the extended conformations (X) and those showing n → π* interactions (np) have been carried out by means of DFT calculations. Solvent effects have been shown to be very important when stabilising np conformations, particularly with polar solvents. This was shown by the shortening of C⋯O intramolecular distances and the increase in the relative energies favouring the np conformation with the dielectric constant of the solvent. The charge transfer between the O donor and the acceptor carbonyl group, assessed by second order perturbation energies, E(2), also shows an increase in the E(2) values with the dielectric constant of the solvent

    Relationship between the learning styles preferences and academic achievement

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    The individual learning differences that have been much explored relate to differences in personality, learning styles, strategies and conceptual of learning. This article studies the learning style profile exhibited by students towards the academic achievement in Malaysian Polytechnic. The relationship between learning styles of Polytechnic students and their academic achievement based on VARK learning styles model. The target population was international business students of Malaysian Polytechnic. By means of randomly sampling method, 103 students were selected as sample of research. By descriptive - survey research method and a questionnaire adapted from VARK Learning Style Index, required data were collected. According to the results, no significantly difference between learning style and academic achievement of students. Students academic achievement was quite similar to their individual learning styles. These facts reveal that each learning style has its own strengths and weaknesses

    Notes on a scandal: the official enquiry into deviance and corruption in New Zealand police

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    Since 2004, the New Zealand Police Service has been engulfed by a series of scandals relating to allegations that officers have committed rape and sexual assault and conducted inappropriate sexual relations with vulnerable people. Moreover, it has been claimed that other officers engaged in corrupt practices to thwart the investigation and prosecution of criminal behaviour of police officers. In 2007, a Commission of Inquiry report established a program of reform intended to shape the future direction of the police service. This article provides an overview of these scandals, the context in which they have emerged, and the political and policing response to them. The analysis contained in the Commission report is compared with that offered by comparable investigations of police deviance and corruption in other countries. The methodological and conceptual limitations of the Commission are outlined and the prospects of the recommendations are considered

    The Allen Telescope Array: The First Widefield, Panchromatic, Snapshot Radio Camera for Radio Astronomy and SETI

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    The first 42 elements of the Allen Telescope Array (ATA-42) are beginning to deliver data at the Hat Creek Radio Observatory in Northern California. Scientists and engineers are actively exploiting all of the flexibility designed into this innovative instrument for simultaneously conducting surveys of the astrophysical sky and conducting searches for distant technological civilizations. This paper summarizes the design elements of the ATA, the cost savings made possible by the use of COTS components, and the cost/performance trades that eventually enabled this first snapshot radio camera. The fundamental scientific program of this new telescope is varied and exciting; some of the first astronomical results will be discussed.Comment: Special Issue of Proceedings of the IEEE: "Advances in Radio Telescopes", Baars,J. Thompson,R., D'Addario, L., eds, 2009, in pres

    The Allen Telescope Array Pi GHz Sky Survey I. Survey Description and Static Catalog Results for the Bootes Field

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    The Pi GHz Sky Survey (PiGSS) is a key project of the Allen Telescope Array. PiGSS is a 3.1 GHz survey of radio continuum emission in the extragalactic sky with an emphasis on synoptic observations that measure the static and time-variable properties of the sky. During the 2.5-year campaign, PiGSS will twice observe ~250,000 radio sources in the 10,000 deg^2 region of the sky with b > 30 deg to an rms sensitivity of ~1 mJy. Additionally, sub-regions of the sky will be observed multiple times to characterize variability on time scales of days to years. We present here observations of a 10 deg^2 region in the Bootes constellation overlapping the NOAO Deep Wide Field Survey field. The PiGSS image was constructed from 75 daily observations distributed over a 4-month period and has an rms flux density between 200 and 250 microJy. This represents a deeper image by a factor of 4 to 8 than we will achieve over the entire 10,000 deg^2. We provide flux densities, source sizes, and spectral indices for the 425 sources detected in the image. We identify ~100$ new flat spectrum radio sources; we project that when completed PiGSS will identify 10^4 flat spectrum sources. We identify one source that is a possible transient radio source. This survey provides new limits on faint radio transients and variables with characteristic durations of months.Comment: Accepted for publication in ApJ; revision submitted with extraneous figure remove

    Global Initiative for Asthma (GINA) strategy 2021 - executive summary and rationale for key changes.

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    The Global Initiative for Asthma (GINA) Strategy Report provides clinicians with an annually updated evidence-based strategy for asthma management and prevention, which can be adapted for local circumstances (e.g., medication availability). This article summarizes key recommendations from GINA 2021, and the evidence underpinning recent changes. GINA recommends that asthma in adults and adolescents should not be treated solely with short-acting beta2-agonist (SABA), because of the risks of SABA-only treatment and SABA overuse, and evidence for benefit of inhaled corticosteroids (ICS). Large trials show that as-needed combination ICS-formoterol reduces severe exacerbations by ≥60% in mild asthma compared with SABA alone, with similar exacerbation, symptom, lung function and inflammatory outcomes as daily ICS plus as-needed SABA. Key changes in GINA 2021 include division of the treatment figure for adults/adolescents into two tracks. Track 1 (preferred) has low-dose ICS-formoterol as the reliever at all steps: as-needed only in Steps 1-2 (mild asthma), and with daily maintenance ICS formoterol (maintenance-and-reliever therapy, MART) in Steps 3-5. Track 2 (alternative) has as-needed SABA across all steps, plus regular ICS (Step 2) or ICS-long-acting beta2-agonist (LABA) (Steps 3-5). For adults with moderate-to-severe asthma, GINA makes additional recommendations in Step 5 for add-on long-acting muscarinic antagonists and azithromycin, with add-on biologic therapies for severe asthma. For children 6-11 years, new treatment options are added at Steps 3-4. Across all age-groups and levels of severity, regular personalized assessment, treatment of modifiable risk factors, self-management education, skills training, appropriate medication adjustment and review remain essential to optimize asthma outcomes
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