380 research outputs found

    Very long optical path-length from a compact multi-pass cell

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    The multiple-pass optical cell is an important tool for laser absorption spectroscopy and its many applications. For most practical applications, such as trace-gas detection, a compact and robust design is essential. Here we report an investigation into a multi-pass cell design based on a pair of cylindrical mirrors, with a particular focus on achieving very long optical paths. We demonstrate a path-length of 50.31 m in a cell with 40 mm diameter mirrors spaced 88.9 mm apart - a 3-fold increase over the previously reported longest path-length obtained with this type of cell configuration. We characterize the mechanical stability of the cell and describe the practical conditions necessary to achieve very long path-lengths

    Exploring the Law of Detrital Zircon: LA-ICP-MS and CA-TIMS Geochronology of Jurassic Forearc Strata, Cook Inlet, Alaska, USA

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    Uranium-lead (U-Pb) geochronology studies commonly employ the law of detrital zircon: A sedimentary rock cannot be older than its youngest zircon. This premise permits maximum depositional ages (MDAs) to be applied in chronostratigraphy, but geochronologic dates are complicated by uncertainty. We conducted laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and chemical abrasion-thermal ionization mass spectrometry (CA-TIMS) of detrital zircon in forearc strata of southern Alaska (USA) to assess the accuracy of several MDA approaches. Six samples from Middle–Upper Jurassic units are generally replete with youthful zircon and underwent three rounds of analysis: (1) LA-ICP-MS of ∌115 grains, with one date per zircon; (2) LA-ICP-MS of the ∌15 youngest grains identified in round 1, acquiring two additional dates per zircon; and (3) CA-TIMS of the ∌5 youngest grains identified by LA-ICP-MS. The youngest single-grain LA-ICP-MS dates are all younger than—and rarely overlap at 2σ uncertainty with—the CA-TIMS MDAs. The youngest kernel density estimation modes are typically several million years older than the CA-TIMS MDAs. Weighted means of round 1 dates that define the youngest statistical populations yield the best coincidence with CA-TIMS MDAs. CA-TIMS dating of the youngest zircon identified by LA-ICP-MS is indispensable for critical MDA applications, eliminating laser-induced matrix effects, mitigating and evaluating Pb loss, and resolving complexities of interpreting lower-precision, normally distributed LA-ICP-MS dates. Finally, numerous CA-TIMS MDAs in this study are younger than Bathonian(?)–Callovian and Oxfordian faunal correlations suggest, highlighting the need for additional radioisotopic constraints—including CA-TIMS MDAs—for the Middle–Late Jurassic geologic time scale

    Passively mode-locked diode-pumped Nd:YVO4 oscillator operating at ultra-low repetition rate

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    We demonstrate the operation of an ultra low repetition rate, high peak power, picosecond diode pumped Nd:YVO4 passively mode locked laser oscillator. Repetition rates even below 1 MHz were achieved with the use of a new design multiple-pass cavity and a semiconductor saturable absorber. Long term stable operation at 1.2 MHz, pulse duration of 16.3 ps and average output power of 470 mW corresponding to 24 KW peak power pulses is reported. This is, to our knowledge, the lowest repetition rate high peak power pulses ever generated directly from a picosecond laser resonator without cavity dumping

    A short report examining the introduction of routine use of patient reported outcome measures in a mixed oncology population

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    Aims: People living with treatable but not curable cancer often experience a range of symptoms related to their cancer and its treatment. During the COVID-19 pandemic, face-to-face consultations were reduced and so remote monitoring of these needs was necessary. University Hospitals Sussex implemented the routine use of electronic remote patient-reported outcome measures (PROMs) in a mixed oncology population, focusing on those with treatable but not curable cancers. Materials and methods: Over a 9-month period, patients were invited to register with My Clinical Outcomes (MCO) – a secure online platform for the collection of electronic PROMs. They were prompted by e-mail to complete assessments (EORTC QLQ-C30, EQ-5D-3L and EQ-5D VAS) routinely every 2 weeks. The team monitored patient scores and changes in these prompted clinical interventions. Results: In total, 324 patients completed at least one assessment. The median number of assessments completed by each patient was eight. The most represented tumour groups were secondary breast (28%), prostate (25%) and other (32%). Median scores for the assessments did not deteriorate in a clinically or numerically significant way for patients living with non-curable conditions for the majority of patients monitored. Conclusion: Routine collection of electronic remote PROMs is an effective and useful strategy to provide real-time clinical feedback to teams. With integration into existing systems, online platforms (such as MCO) could provide efficient and patient-centred information for those providing care for people with cancer

    Multiple sources of Escherichia coli O157

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    Abstract Samples from cattle, other domestic and wild animals, flies, feeds, and water-troughs were collected from 12 cattle farms and tested for Escherichia coli O157. E. coli O157 was isolated from bovine fecal samples on all 12 farms with a within herd prevalence ranging from 1.1% to Ćœ . Ćœ . 6.1%. E. coli O157 was also found in 1 of 90 1.1% equine fecal samples, 2 of 65 3.1% canine Ćœ . Ćœ . fecal samples, 1 of 200 pooled bird samples 0.5% , 2 of 60 pooled fly samples 3.3% , and 10 of Ćœ . Ćœ . 320 3.1% water-trough sample sets biofilm and water . No E. coli O157 were isolated from 300 rodents, 33 cats, 34 assorted wildlife, or 335 cattle feed samples. Indistinguishable pulsed-field gel electrophoresis patterns of XbaI digested chromosomal DNA and Shiga toxin types were observed for bovine and water-trough isolates from two farms and for one equine and two bovine isolates from one farm. q 1998 Elsevier Science B.V

    Exploring the quality of social information disclosed in non-financial reports of Croatian companies

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    By enacting the provisions of Directive 2014/95/EU and the Croatian Accounting Act on disclosing non-financial and diversity information, companies of public interest registering 500 and more employees are required to disclose non-financial information. The purpose of this research is to assess the quality of disclosed social information in non- financial/sustainability reports of Croatian companies. The assessment of the social information was grounded on the framework defined by globally accepted sustainability reporting standards by assessing the quality of social subcategories of human rights, labour practice, community/society and product, measured by attributes of relevance, clarity, verifiability, comparability and clarity. With the overall quality score of 13.16 (out of possible 36), the results prove that Croatian companies do disclose certain social information, but the reliability of this information for benchmarking and competitiveness assessment is questionable, as a consensus on the minimum of information to be disclosed as a fundamental requirement for benchmarking has not yet been reached

    Molecular Basis of Increased Serum Resistance among Pulmonary Isolates of Non-typeable Haemophilus influenzae

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    Non-typeable Haemophilus influenzae (NTHi), a common commensal of the human pharynx, is also an opportunistic pathogen if it becomes established in the lower respiratory tract (LRT). In comparison to colonizing isolates from the upper airway, LRT isolates, especially those associated with exacerbations of chronic obstructive pulmonary disease, have increased resistance to the complement- and antibody-dependent, bactericidal effect of serum. To define the molecular basis of this resistance, mutants constructed in a serum resistant strain using the mariner transposon were screened for loss of survival in normal human serum. The loci required for serum resistance contribute to the structure of the exposed surface of the bacterial outer membrane. These included loci involved in biosynthesis of the oligosaccharide component of lipooligosaccharide (LOS), and vacJ, which functions with an ABC transporter encoded by yrb genes in retrograde trafficking of phospholipids from the outer to inner leaflet of the cell envelope. Mutations in vacJ and yrb genes reduced the stability of the outer membrane and were associated with increased cell surface hyrophobicity and phospholipid content. Loss of serum resistance in vacJ and yrb mutants correlated with increased binding of natural immunoglobulin M in serum as well as anti-oligosaccharide mAbs. Expression of vacJ and the yrb genes was positively correlated with serum resistance among clinical isolates. Our findings suggest that NTHi adapts to inflammation encountered during infection of the LRT by modulation of its outer leaflet through increased expression of vacJ and yrb genes to minimize recognition by bactericidal anti-oligosaccharide antibodies

    Drivers and technology-related obstacles in moving to multichannel retailing

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    Today, multichannel retailing is a key strategic issue for most retailers. Yet, while there are many drivers associated with retailers going multichannel so too are there technology-related obstacles, however, few prior empirical studies explore these themes. In light of this, by using a multi-case approach to understand the key drivers and technology-related obstacles associated with retailers moving to multichannel retailing our study makes two key contributions. First, we extend prior theory by providing novel empirical insights into the main drivers underpinning retailers using a multichannel strategy. We find that meeting customer needs and increasing sales were the primary drivers behind retailers using the strategy, although there is diversity in the way retailers respond to these motives. Second, we provide empirical support for a proposed theoretical framework which summarises the key technology-related obstacles retailers encounter when going multichannel, by stage of implementation. The framework reveals that retailers face technology-related obstacles when implementing a multichannel strategy due to the need to switch/acquire resources and achieve channel integration. Furthermore, the framework highlights that these resource and channel integration issues are often interrelated with each other and with other staff engagement and cultural issues, vary by retailer and stage of implementation, and pose greater obstacles to retailers using new and multiple channels than the extant literature suggests
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