Siga este enlace para ver otros tipos de publicaciones sobre el tema: Exposure Merger.
Artículos de revistas sobre el tema "Exposure Merger"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores artículos de revistas para su investigación sobre el tema "Exposure Merger".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Jain,, Hardik. "Post Merger Financial Analysis: An AI & ML tool for Banks". INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 08, n.º 04 (13 de abril de 2024): 1–5. http://dx.doi.org/10.55041/ijsrem30659.
Texto completoResumen
This paper models the significance of mergers and acquisitions (M&A) in reviving the growth of obsolete or low performing organizations. In line with adapting to the changing circumstances and limiting exposure to the volatility, higher level of capital backing is necessary which only consolidation can achieve (Mantravadi, 2007). Banks being economic institutions are expected to be more directly involved in inclusive growth by including the whole economy in the growth and development, therefore, to support this belief, merger and acquisition as a strategic tool is studied. M&A is considered as one of the significant tools for organizational restructuring and value addition considering the volatility prevailing in the present business environment. It enables organizations to expand their horizon of operation, mitigating risks, explore new markets and geographical locations by creating synergies thereby increasing profitability gaining through competitive advantage. It includes the study of the factors and series of events that led the Government of India (GOI) to the merger of 10 public sector banks (PSB) into 4 merged entities, adoption of M&A as technique to achieve objectives moreover it studies acquisition of the Allahabad Bank by the Indian Bank to identify and interpret the purpose and potential of consolidation backed by a comparative analysis of pre-acquisition and post-acquisition performance of the above-mentioned banks. Key Words: Mergers and Acquisitions, Public Sector Banking (PSB), Indian Bank, Allahabad Bank, NPA and Synergy.
2
Balliro, Rosa. "Food for /θɔt/ or /θɑt/?" Lifespans and Styles 7, n.º 2 (18 de diciembre de 2021): 48–56. http://dx.doi.org/10.2218/ls.v7i2.2021.6643.
Texto completoResumen
The English low back vowel merger, where words like caught and cot are pronounced identically, is a well-studied phenomenon. Generally, these studies focus on mergers within given regions, comparing vowels of non-mobile individuals. My research differs in exploring the effects of relocation. I examine pronunciation differences of vowels in differently gendered twins from England who moved to Canada as children. Despite growing up in similar environments, their vowel patterns differ: there is some evidence of merger in the female’s but not the male’s vowels. This suggests that mobility and exposure to a new dialect may affect pronunciation changes but are not the sole factors.
3
Hall, Jason, Matthew Pinnuck y Matthew Thorne. "Market risk exposure of merger arbitrage in Australia". Accounting & Finance 53, n.º 1 (31 de octubre de 2011): 185–215. http://dx.doi.org/10.1111/j.1467-629x.2011.00453.x.
Texto completo
4
Davidow, Joel. "United States Antitrust Developments in the New Millennium". World Competition 24, Issue 3 (1 de septiembre de 2001): 425–42. http://dx.doi.org/10.54648/359608.
Texto completoResumen
US antitrust in the new millennium has been characterised both by successes and challenges. The successes include additional exposure of major international cartels, exposure of foreign corporate officials to US prison sentences for cartel activity, further adoption or strengthening of foreign antitrust systems, and deeper co-operation in regard to anti-cartel and merger control enforcement. Merger relief has become quite strict, with firm insistence on fix it first solutions that are quite certain to happen. Challenges include trying to win the Microsoft case on appeal, learning how to deal with private actions involving damages stemming from worldwide cartels and curbing the runaway proliferation of merger control systems that lay too many burdens on largely unobjectionable but highly international transactions. The new administration will undoubtedly continue many of the international initiatives of its predecessor, but is likely to be more sceptical of populist antitrust approaches such as vertical cases or predatory practice monopolisation cases.
5
Munson, Bradley, Emmanouil Chatzopoulos y Pavel A. Denissenkov. "Improved Models of R Coronae Borealis Stars". Astrophysical Journal 939, n.º 1 (1 de noviembre de 2022): 45. http://dx.doi.org/10.3847/1538-4357/ac9476.
Texto completoResumen
Abstract We present an improved numerical method to model subsolar He+CO-WD merger progenitors of R Corona Borealis stars that builds on our previous work. These improvements include a smooth entropy transition from the core to the envelope of the post-merger, inclusion of single-zone nucleosynthesis to mimic the effects of burning during the merger event, and post-processing the models with a larger nuclear network for analysis of s-process nucleosynthesis. We perform a parameter study to understand the effects of the entropy transition, peak temperature, and overshooting on our models. The models that best agree with observations of R Corona Borealis stars are processed with a much larger nuclear network to investigate s-process nucleosynthesis and the dredge-up of s-process products into the outer envelope in detail. We present a model with a significant enhancement in s-process elements, which also agrees with observed surface abundances and isotopic ratios of 16O/16O and C/O between 1 and 10. Finally, we find that the neutron exposure and initial neutron densities this model requires to obtain such an enhancement are much more consistent with i-process nucleosynthesis.
6
Jensen, Johan Høy, Esben Meulengracht Flachs, Janne Skakon, Naja Hulvej Rod y Jens Peter Bonde. "Dual impact of organisational change on subsequent exit from work unit and sickness absence: a longitudinal study among public healthcare employees". Occupational and Environmental Medicine 75, n.º 7 (14 de mayo de 2018): 479–85. http://dx.doi.org/10.1136/oemed-2017-104865.
Texto completoResumen
ObjectivesWe investigated work-unit exit, total and long-term sickness absence following organisational change among public healthcare employees.MethodsThe study population comprised employees from the Capital Region of Denmark (n=14 388). Data on reorganisation at the work-unit level (merger, demerger, relocation, change of management, employee layoff or budget cut) between July and December 2013 were obtained via surveys distributed to the managers of each work unit. Individual-level data on work-unit exit, total and long-term sickness absence (≥29 days) in 2014 were obtained from company registries. For exposure to any, each type or number of reorganisations (1, 2 or ≥3), the HRs and 95% CIs for subsequent work-unit exit were estimated by Cox regression, and the risk for total and long-term sickness absence were estimated by zero-inflated Poisson regression.ResultsReorganisation was associated with subsequent work-unit exit (HR 1.10, 95% CI 1.01 to 1.19) in the year after reorganisation. This association was specifically important for exposure to ≥3 types of changes (HR 1.52, 95% CI 1.30 to 1.79), merger (HR 1.29, 95% CI 1.12 to 1.49), demerger (HR 1.41, 95% CI 1.16 to 1.71) or change of management (HR 1.24, 95% CI 1.11 to 1.38). Among the employees remaining in the work unit, reorganisation was also associated with more events of long-term sickness absence (OR 1.15, 95% CI 1.00 to 1.33), which was particularly important for merger (OR 1.31, 95% CI 1.00 to 1.72) and employee layoff (OR 1.31, 95% CI 1.08 to 1.59).ConclusionsSpecific types of reorganisation seem to have a dual impact on subsequent work-unit exit and sickness absence in the year after change.
7
Chernomordik, Leonid V., Eugenia Leikina, Vadim Frolov, Peter Bronk y Joshua Zimmerberg. "An Early Stage of Membrane Fusion Mediated by the Low pH Conformation of Influenza Hemagglutinin Depends upon Membrane Lipids". Journal of Cell Biology 136, n.º 1 (13 de enero de 1997): 81–93. http://dx.doi.org/10.1083/jcb.136.1.81.
Texto completoResumen
While the specificity and timing of membrane fusion in diverse physiological reactions, including virus–cell fusion, is determined by proteins, fusion always involves the merger of membrane lipid bilayers. We have isolated a lipid-dependent stage of cell–cell fusion mediated by influenza hemagglutinin and triggered by cell exposure to mildly acidic pH. This stage preceded actual membrane merger and fusion pore formation but was subsequent to a low pH–induced change in hemagglutinin conformation that is required for fusion. A low pH conformation of hemagglutinin was required to achieve this lipid-dependent stage and also, downstream of it, to drive fusion to completion. The lower the pH of the medium applied to trigger fusion and, thus, the more hemagglutinin molecules activated, the less profound was the dependence of fusion on lipids. Membrane-incorporated lipids affected fusion in a manner that correlated with their dynamic molecular shape, a characteristic that determines a lipid monolayer's propensity to bend in different directions. The lipid sensitivity of this stage, i.e., inhibition of fusion by inverted cone–shaped lysophosphatidylcholine and promotion by cone-shaped oleic acid, was consistent with the stalk hypothesis of fusion, suggesting that fusion proteins begin membrane merger by promoting the formation of a bent, lipid-involving, stalk intermediate.
8
Troja, E., H. van Eerten, B. Zhang, G. Ryan, L. Piro, R. Ricci, B. O’Connor, M. H. Wieringa, S. B. Cenko y T. Sakamoto. "A thousand days after the merger: Continued X-ray emission from GW170817". Monthly Notices of the Royal Astronomical Society 498, n.º 4 (12 de octubre de 2020): 5643–51. http://dx.doi.org/10.1093/mnras/staa2626.
Texto completoResumen
ABSTRACT Recent observations with the Chandra X-ray telescope continue to detect X-ray emission from the transient GW170817. In a total exposure of 96.6 ks, performed between 2020 March 9 and 16 (935–942 d after the merger), a total of 8 photons are measured at the source position, corresponding to a significance of ≈5σ. Radio monitoring with the Australian Telescope Compact Array (ATCA) shows instead that the source has faded below our detection threshold (<33 $\mu$Jy, 3σ). By assuming a constant spectral index of β = 0.585, we derive an unabsorbed X-ray flux of ≈1.4 × 10−15 erg cm−2 s−1, higher than earlier predictions, yet still consistent with a simple structured jet model. We discuss possible scenarios that could account for prolonged emission in X-rays. The current data set appears consistent both with energy injection by a long-lived central engine and with the onset of a kilonova afterglow, arising from the interaction of the sub-relativistic merger ejecta with the surrounding medium. Long-term monitoring of this source will be essential to test these different models.
9
Nguyen, Hoai-Luu Q. "Are Credit Markets Still Local? Evidence from Bank Branch Closings". American Economic Journal: Applied Economics 11, n.º 1 (1 de enero de 2019): 1–32. http://dx.doi.org/10.1257/app.20170543.
Texto completoResumen
This paper studies whether distance shapes credit allocation by estimating the impact of bank branch closings during the 2000s on local access to credit. To generate plausibly exogenous variation in the incidence of closings, I use an instrument based on within-county, tract-level variation in exposure to post-merger branch consolidation. Closings lead to a persistent decline in local small business lending. Annual originations fall by $453,000 after a closing, off a baseline of $4.7 million, and remain depressed for up to six years. The effects are very localized, dissipating within six miles, and are especially severe during the financial crisis. (JEL G21, G34, L22, R12, R32)
10
Starr, Rebecca Lurie. "Cross-dialectal Awareness and Use of the Bath-Trap Distinction in Singapore: Investigating the Effects of Overseas Travel and Media Consumption". Journal of English Linguistics 47, n.º 1 (23 de enero de 2019): 55–88. http://dx.doi.org/10.1177/0075424218819740.
Texto completoResumen
Lay observers and linguists have claimed that ongoing phonological and lexical changes in Singapore English may be attributed to increased exposure to American English via media consumption (Poedjosoedarmo 2000; Deterding 2007; Leow 2011). Little is known, however, regarding Singaporeans’ explicit knowledge of the dialect features of other regions, and how this knowledge is shaped by social and parasocial contact. The present study investigates a well-known difference among regional English dialects: the realization of vowels in the bath and trap lexical sets. 1167 Singaporeans are surveyed regarding their own pronunciation of bath and trap words, as well as their perceptions of how these words are pronounced in California and London. While Singaporeans are found to generally retain a conservative bath-trap distinction, media consumption and travel experience, as well as gender and education level, have significant impacts on reported use. Explicit knowledge of the US bath-trap merger is found to be poor relative to the high US media consumption rate, illustrating the limits of media as a source of sociolinguistic knowledge. Contrasting sharply with the rise of postvocalic rhoticity, reluctance to adopt the bath-trap merger is argued to stem from both functional and ideological factors; conservatism in this feature complicates proposals of a wholesale Americanization of Singapore English.
11
Yu, Jitong. "With initial exposure to equities, which strategy delivers a better return?" Advances in Economics, Management and Political Sciences 14, n.º 1 (13 de septiembre de 2023): 250–57. http://dx.doi.org/10.54254/2754-1169/14/20230832.
Texto completoResumen
More and more people are getting into the investment industry, which is not an easy job for some beginners. Complicated strategies and varied portfolios can often feel overwhelming and also lead investors into one misunderstanding after another. In order to reduce the hassle of investing, this article will pick the four most common and easy-to-understand strategies: momentum investing, comparing PEG ratios, merger arbitrage strategy, and market-neutral trade. From a version of beginner on how to start an investment portfolio. The background of the eight films selected in this paper will be introduced first, mainly about what the film does. Moreover, the uses of the strategy will be present, as the theory behind them. Then, this paper will present detailed progress, including stock price tendency, results, and future improvements. The calculation of PEG ratios and market-neutral strategy will also be included. Finally, a comparison is also made in this paper, which can deliver the feasibility of each strategy base on the four pairs of trades made. It also introduces how a manager new to stocks makes a decision and the results obtained and sums up a strategy that is most suitable for beginners to invest. However, it is just a brief explanation; different investment portfolios need to use different investment strategies and try more to get more returns.
12
Churazov, E., I. Khabibullin, N. Lyskova, R. Sunyaev y A. M. Bykov. "Tempestuous life beyond R500: X-ray view on the Coma cluster with SRG/eROSITA". Astronomy & Astrophysics 651 (julio de 2021): A41. http://dx.doi.org/10.1051/0004-6361/202040197.
Texto completoResumen
This is the first paper in a series of studies of the Coma cluster using the SRG/eROSITA X-ray data obtained in the course of the calibration and performance verification observations. The data cover a ~3° × 3° area around the cluster with a typical exposure time of more than 20 ks. The stability of the instrumental background and operation of the SRG observatory in the scanning mode provided us with an excellent data set for studies of the diffuse emission up to a distance of ~1.5R200 from the Coma center. In this study, we discuss the rich morphology revealed by the X-ray observations (also in combination with the SZ data) and argue that the most salient features can be naturally explained by a recent (ongoing) merger with the NGC 4839 group. In particular, we identify a faint X-ray bridge connecting the group with the cluster, which is convincing proof that NGC 4839 has already crossed the main cluster. The gas in the Coma core went through two shocks, first through the shock driven by NGC 4839 during its first passage through the cluster some gigayear ago and, more recently, through the “mini-accretion shock” associated with the gas settling back to quasi-hydrostatic equilibrium in the core. After passing through the primary shock, the gas should spend much of the time in a rarefaction region, where radiative losses of electrons are small, until the gas is compressed again by the mini-accretion shock. Unlike “runway” merger shocks, the mini-accretion shock does not feature a rarefaction region downstream and, therefore, the radio emission can survive longer. Such a two-stage process might explain the formation of the radio halo in the Coma cluster.
13
Aghaei Abchouyeh, Maryam, Maurice H. P. M. van Putten y Lorenzo Amati. "Observational Prospects of Double Neutron Star Mergers and Their Multimessenger Afterglows: LIGO Discovery Power, Event Rates, and Diversity". Astrophysical Journal 952, n.º 2 (26 de julio de 2023): 157. http://dx.doi.org/10.3847/1538-4357/acd114.
Texto completoResumen
Abstract The double neutron star (DNS) merger event GW170817 signifies the first multimessenger (MM) event with electromagnetic-gravitational (EM-GW) observations. LIGO-Virgo-KAGRA observational runs O4-5 promise to detect similar events and as yet unknown GW signals, which require confirmation in two or more detectors with comparable performance. To this end, we quantify duty cycles of comparable science quality of data in coincident H1L1-observations, further to seek consistent event rates of astrophysical transients in upcoming EM-GW surveys. Quite generally, discovery power scales with exposure time, sensitivity, and critically depends on the percentage of time when detectors operate at high quality. We quantify coincident duty cycles over a time-frequency domain W × B, defined by segments of duration W = 8 s, motivated by a long-duration descending GW-chirp during GRB170817A, and the minimum detector noise over about B = 100–250 Hz. This detector yield factor satisfies 1%–25% in S5-6 and O1-O3ab, significantly different from duty cycles of H1 and L1 individually with commensurable impact on consistency in event rates in EM-GW surveys. Significant gain in discovery power for signals whose frequency varies slowly in time may be derived from improving detector yield factors by deploying time-symmetric data analysis methods. For O4-5, these can yield improvements by factors up to ( 10 5 ) relative to existing data and methods. Furthermore, the diversity of MM afterglows to DNS mergers may be greatest for systems similar to GW170817 but possibly less so for systems of substantially different mass such as GW190425. We summarize our findings with an outlook on EM-GW surveys during O4-5 and perspectives for next-generation GRB missions like THESEUS.
14
Rauch, B. F., W. V. Zober, Q. Abarr, Y. Akaike, W. R. Binns, R. F. Borda, R. G. Bose et al. "From SuperTIGER to TIGERISS". Instruments 8, n.º 1 (11 de enero de 2024): 4. http://dx.doi.org/10.3390/instruments8010004.
Texto completoResumen
The Trans-Iron Galactic Element Recorder (TIGER) family of instruments is optimized to measure the relative abundances of the rare, ultra-heavy galactic cosmic rays (UHGCRs) with atomic number (Z) Z ≥ 30. Observing the UHGCRs places a premium on exposure that the balloon-borne SuperTIGER achieved with a large area detector (5.6 m2) and two Antarctic flights totaling 87 days, while the smaller (∼1 m2) TIGER for the International Space Station (TIGERISS) aims to achieve this with a longer observation time from one to several years. SuperTIGER uses a combination of scintillator and Cherenkov detectors to determine charge and energy. TIGERISS will use silicon strip detectors (SSDs) instead of scintillators, with improved charge resolution, signal linearity, and dynamic range. Extended single-element resolution UHGCR measurements through 82Pb will cover elements produced in s-process and r-process neutron capture nucleosynthesis, adding to the multi-messenger effort to determine the relative contributions of supernovae (SNe) and Neutron Star Merger (NSM) events to the r-process nucleosynthesis product content of the galaxy.
15
Ayers, Benjamin C., Craig E. Lefanowicz y John R. Robinson. "The Financial Statement Effects of Eliminating the Pooling-of-Interests Method of Acquisition Accounting". Accounting Horizons 14, n.º 1 (1 de marzo de 2000): 1–19. http://dx.doi.org/10.2308/acch.2000.14.1.1.
Texto completoResumen
Accounting standard setters have become increasingly concerned with the perceived manipulation of financial statements afforded by the pooling-of-interests (pooling) method of accounting for corporate acquisitions. While different restrictions have been discussed, in September 1999 the Financial Accounting Standards Board (FASB) issued an Exposure Draft to eliminate the pooling method. This study provides a basis for evaluating restrictions on the pooling method by analyzing the financial statement effects on pooling acquisitions made by public corporations over the period 1992 through 1997. Using these acquisitions we (1) quantify the scope of the “pooling problem,” (2) estimate the financial statement repercussions of eliminating the pooling method, and (3) examine the effects of restricting pooling accounting to business combinations meeting various “merger of equals” restrictions. While our analysis does not address whether restrictions on the pooling method will influence the nature or level of acquisition activity, the results indicate that the pooling method generates enormous amounts of unrecognized assets, across individual acquisitions, and in aggregate. In addition, our results suggest that recording and amortizing these assets generate significant balance sheet and income statement effects that vary with industry. Regarding restrictions on the pooling method, our analysis indicates that size restrictions would significantly reduce the number and value of pooling acquisitions and unrecognized assets generated by these acquisitions.
16
Srivastava, Nidhi, Usha Kumari, Amita Kumari Rai, Swati Mittal y Ajay Kumar Mittal. "Alterations in the Gill Filaments and Secondary Lamellae of Cirrhinus mrigala Exposed to “Nuvan,” an Organophosphorus Insecticide". Journal of Histology 2014 (27 de octubre de 2014): 1–11. http://dx.doi.org/10.1155/2014/190139.
Texto completoResumen
The alterations in the epithelium of the gill filaments and the secondary lamellae of the gills of Cirrhinus mrigala, on exposure to “Nuvan,” have been explored in the present investigation using light and scanning electron microscopy. The fishes were exposed to two sublethal concentrations, 5 mg/L and 15 mg/L, of “Nuvan.” The changes are more rapid and intensive at higher concentration than at lower concentration, suggesting that the changes are dose dependent. Increase in thickness of epithelium covering secondary lamellae, merger of epithelium of gill filaments and adjacent secondary lamellae, and aneurysm is considered to reduce efficiency of gills for gaseous exchange. A significant decline in the density and area of the mucous goblet cells in the epithelium of the gill filaments and the secondary lamellae of C. mrigala exposed to “Nuvan” could be correlated with excessive loss of the secretory contents of these cells, uncompensated by their production in sufficient quantities. The histopathological changes, in general, take longer time to recover in the fishes exposed to 15 mg/L than those exposed to 5 mg/L indicating that the changes in fishes exposed to higher concentration are more severe than those at lower concentration of the insecticide.
17
Wang, Chen, Junfeng Wang, Mauro Dadina, Giuseppina Fabbiano, Martin Elvis, Stefano Bianchi y Matteo Guainazzi. "Deep Chandra Observation of the Remarkable Ionization Cones of NGC 5252". Astrophysical Journal 962, n.º 2 (1 de febrero de 2024): 188. http://dx.doi.org/10.3847/1538-4357/ad18c9.
Texto completoResumen
Abstract Seyfert galaxy NGC 5252 harbors enormously extended ionization cones that have been previously detected in the optical and X-ray band, offering a unique opportunity to investigate the interaction between the central active galactic nucleus (AGN) and the surrounding gas in the AGN host galaxy. We present deep Chandra imaging spectroscopy of NGC 5252 with a total exposure time of 230 ks. The morphology in the soft X-rays shows resolved extended structure from the nucleus to a large radial distance, and for the first time we detect the outermost X-ray arc at ∼20 kpc. The X-ray cone mostly follows the direction of the optical ionization cones in the southeast and northwest directions, about 20° misaligned with the major axis of the galactic disk of NGC 5252. Fitting the spectra extracted from radial sectors with photoionization models supports that extended emission is mainly photoionized by the central AGN. We also examine the variation of the photoionization parameter along the radial extension and infer a decreasing ionizing continuum of the central engine by a factor of ∼50 over the past 64,000 yr. These findings are consistent with previous suggestions that NGC 5252 resembles a quasar relic with an M ∼ 109 M ⊙ supermassive black hole that went through a minor merger event and switched to a low accretion rate state.
18
Rose, Peter S. "The Distribution of Outcomes from Corporate Mergers: Evidence from Commercial Bank Acquisition Strategies". Journal of Accounting, Auditing & Finance 10, n.º 2 (abril de 1995): 343–64. http://dx.doi.org/10.1177/0148558x9501000210.
Texto completoResumen
Bank mergers in the United States have reshaped the structure of American banking into an increasingly consolidated industry. Yet the merger literature in banking, like the literature for most other industries, reaches sharply conflicting conclusions regarding the outcomes for merging banking firms, their shareholders, and the public, due perhaps to variable agency cost exposures and competitive market structures. Drawing on a random sample of more than 1,200 acquiring and acquired U.S. banking firms from 1970 through 1988, the study finds a nearly symmetric distribution of increasing and decreasing ex post returns to equity capital in the post-merger period. The acquiring banking firms experiencing increasing equity-capital returns displayed evidence of superior labor productivity in asset and revenue generation as well as enjoying postmerger increases in market concentration. Acquiring institutions also benefitted from faster ex post capital growth when they acquired banking firms operating in more concentrated banking markets. The positive market-concentration, post-merger-return relationship found in the study highlights the importance of a continuing active role for antitrust policy in protecting the public interest from an excessive concentration of market power in the hands of a few banks. Some takeovers enhance economic efficiency, some degrade it, and the balance of effects, though not fully known, is most likely a close one. Scherer (1988)
19
Paggi, A., G. Fabbiano, E. Nardini, M. Karovska, M. Elvis y J. Wang. "Dissecting the Extended X-Ray Emission in the Merging Pair NGC 6240: Photoionization and Winds". Astrophysical Journal 927, n.º 2 (1 de marzo de 2022): 166. http://dx.doi.org/10.3847/1538-4357/ac5025.
Texto completoResumen
Abstract We present a detailed spectral and imaging analysis of the central 15″ radius (∼7.5 kpc) region of the merger galaxy NGC 6240 that makes use of all the available Chandra-ACIS data (0.3–3 keV effective exposure of ∼190 ks). This region shows extended X-ray structures with lower-energy counterparts imaged in CO, [O iii], and Hα line emission. We find both photoionized phases of possible nuclear excitation and thermal shock-excited emission in the different large-scale components: the northwest “loop” detected in Hα, the region surrounding the two nuclei, the large outflow region to the northeast detected in [O iii], and the southern X-ray extensions. The latter could be the ionization cone of the northern nucleus, with the N counterpart being obscured by the galaxy disk. The radial distribution of the X-ray surface brightness suggests a confined hot interstellar medium at r < 2.5 kpc, with a free-flowing wind at larger radii; if the confinement is magnetic, we estimate B-field values of ∼100 μG, similar to those measured in the halo of M82. The thermal gas of the extended halo at kT ∼ 1 keV absorbs soft X-rays from the active galactic nucleus, but not the extreme ultraviolet radiation leading to a rapid increase in F [O III]/F X beyond ∼3 kpc. The α-element to Fe abundance ratios of the thermal components in the different regions of the extended X-ray emission are generally compatible with Type II supernova yields, confirming the importance of active star formation in NGC 6240.
20
Dorodnykh, Ekaterina. "Determinants of stock exchange integration: evidence in worldwide perspective". Journal of Economic Studies 41, n.º 2 (4 de marzo de 2014): 292–316. http://dx.doi.org/10.1108/jes-08-2012-0111.
Texto completoResumen
Purpose – This paper contains an empirical analysis of determinants of international integration projects over the time period 1995-2010. After a broad discussion of the existent literature, the investigation combines a large number of potentially relevant determinants for the explanation of whether stock exchanges are participating in formal integration projects. The paper aims to discuss these issues. Design/methodology/approach – The methodology is based on multistage statistical data analysis, using correlation and cluster analyses to investigate the presence of integration trend between existing stock exchange projects, while multivariable logit regression examines the determinants of stock exchange integration. Findings – The paper confirms empirically the set of drivers of financial integration. Moreover, the paper provides quantitative estimations of probability of stock exchange integration estimated for different explanatory variables. The paper demonstrates that financial harmonization, cross-membership-agreements, for-profit corporate structure, trading engine and regional integration are important drivers of stock exchange integration. By contrast, high size of stock exchange market has negative impact on the likelihood of successful merger. This result is, especially, important in terms of financial regulation. Practical implications – Results highlight the importance of stock exchange market in terms of exposure to systemic shocks and the linkages with the overall size of the economy. Originality/value – The paper contributes to the existing literature and extends the analysis of determinants of stock exchange integration. In particular, the existence of de jure stock market integration projects suggests to design a special regulatory framework in order to benefit the important consequences of the integration phenomenon and to decrease the risk of financial contagion.
21
Benjamin-Ohwodede, Jacinta, Adekunle Mamudu y Simeon Nyemike Awunor. "The Effectiveness of Hybrid Learning in English Pronunciation Pedagogy in the Nigerian ESL Context". JELITA 5, n.º 1 (26 de febrero de 2024): 81–103. http://dx.doi.org/10.56185/jelita.v5i1.550.
Texto completoResumen
This paper is a study on the effectiveness of hybrid learning; a blend of traditional and technology-based training, vis-à-vis the second language (L2) learner of English pronunciation. Specifically, our motivation is centred on the functionality of combining the habitual classroom teaching style with the Telegram app (a mobile-based technological tool) for studies relating to speech production and perception. The methodical procedure and design for this study is both quantitative and descriptive; employing the use of a multiple-choice questionnaire in data collection from 401 Nigerian undergraduate and postgraduate students in the University of Benin, Nigeria, to ascertain the effectiveness of digital designs and stratagems. Pie charts are employed to display multiple divisions of the study's data comparison. This study emphasizes the Online-Driver Blended Learning Model; such a pedagogical approach exposes the L2 learner to a more involved and effective way of understanding how to avoid imposing an unfamiliar accent upon the target language. Consequently, we see a merger of online practical exercises and exposure to uploaded multimodal texts and native speakers' spoken data (audio-visual recordings/voice notes) with scheduled direct classroom interludes. Findings confirm that exploiting such a hybrid model enhances students' cognitive abilities and retentive capacity regarding English pronunciation. Such digital audio-visual tools are paramount phonetic strategies for learning how to avoid unacceptable phonetic alterations. Thus, we see the effectiveness of integrating the Telegram app into the traditional brick-and-mortar educational method in handling problems associated with speech sound production and second-language phonological interference.
22
Windhorst, Rogier A., Sam M. Pascarelle y William C. Keel. "Deep HST Imaging of a Galaxy Cluster at z = 2.40". Symposium - International Astronomical Union 171 (1996): 474–75. http://dx.doi.org/10.1017/s0074180900233925.
Texto completoResumen
We present a 67-orbit HST/WFPC2 exposure on the weak radio galaxy 53W002 at z=2.390 and its surrounding cluster. Color Plate 1 shows 12 orbits in IF814W & VF606W, and 24 in BF450W. Potential cluster members were identified through 15 orbits in F410M, optimized for narrow-band searches for compact Lyα objects at z≃2.4 (P96), and confirmed through spectroscopy (W91, P96); 16 candidates were found with significant narrow-band emission in F410M: 4 out of 5 had a confirming MMT spectroscopic redshift at z≃2.40 (P96). All are located within 60″ from 53W002, or ∼ 0.24h–1100 Mpc (qo=0.5) at z ≃2.4, the physical scale of a group or small galaxy cluster. One object contains a weak (variable) AGN, another is a merger with two companions. Their underlying young stellar population is very compact, with rh.l. ≃0.2″ (≃ 0.8h–1100 kpc), and considerably fainter than the L∗-value at z∼2.4, implying sub-galactic sized objects. These results may explain why ground-based Lya searches for PG's have been largely unsuccessful. The narrow-line galaxy 53W002 was imaged in the PC at ∼0.07″ FWHM (WK95, see also W94). Its AGN component is ≤ 20±4% of the total continuum, surrounded by an extended r1/4-envelope with rh.l. ≃1.1″ (4.3 kpc), and has an SED of ∼0.3 Gyr in the center to ∼0.5-1.0 Gyr at ∼4 kpc. A one-sided cloud is seen ∼1.8 kpc West, ∼0.3 mag bluer than the SED, aligned with the radio source and its Ly-α cloud, presumably weak scattered AGN light, and/or jet-induced star-formation.
23
Dey, Arjun, Joan R. Najita, Sergey E. Koposov, J. Josephy-Zack, Gabriel Maxemin, Eric F. Bell, C. Poppett et al. "DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of Our Nearest Neighbor". Astrophysical Journal 944, n.º 1 (1 de febrero de 2023): 1. http://dx.doi.org/10.3847/1538-4357/aca5f8.
Texto completoResumen
Abstract We present Dark Energy Spectroscopic Instrument (DESI) observations of the inner halo of M31, which reveal the kinematics of a recent merger—a galactic immigration event—in exquisite detail. Of the 11,416 sources studied in 3.75 hr of on-sky exposure time, 7438 are M31 sources with well-measured radial velocities. The observations reveal intricate coherent kinematic structure in the positions and velocities of individual stars: streams, wedges, and chevrons. While hints of coherent structures have been previously detected in M31, this is the first time they have been seen with such detail and clarity in a galaxy beyond the Milky Way. We find clear kinematic evidence for shell structures in the Giant Stellar Stream, the Northeast Shelf, and Western Shelf regions. The kinematics are remarkably similar to the predictions of dynamical models constructed to explain the spatial morphology of the inner halo. The results are consistent with the interpretation that much of the substructure in the inner halo of M31 is produced by a single galactic immigration event 1–2 Gyr ago. Significant numbers of metal-rich stars ([Fe/H] > − 0.5) are present in all of the detected substructures, suggesting that the immigrating galaxy had an extended star formation history. We also investigate the ability of the shells and Giant Stellar Stream to constrain the gravitational potential of M31, and estimate the mass within a projected radius of 125 kpc to be log 10 M NFW ( < 125 kpc ) / M ⊙ = 11.80 − 0.10 + 0.12 . The results herald a new era in our ability to study stars on a galactic scale and the immigration histories of galaxies.
24
Deshmukh, Pooja y Sushil Paliwal. "Pharmacy education 2.0 with special reference to digital India". Multidisciplinary Reviews 7, n.º 4 (22 de enero de 2024): 2024065. http://dx.doi.org/10.31893/multirev.2024065.
Texto completoResumen
Indian pharmacy education has grown and changed, producing trained individuals needed in the pharmaceutical and healthcare industries. Pharmacy education in India is reviewed here, noting its merits, weaknesses, and future possibilities. India has many pharmacy schools, with a concentration in Maharashtra, Karnataka, and Andhra Pradesh. The Pharmacy Council of India (PCI) regulates curriculum and infrastructure. Diploma, undergraduate (B. Pharm), postgraduate (M. Pharm), and doctoral (Ph.D.) pharmacy programs serve students with varied professional goals. Students learn basic pharmaceutical sciences, technology, medication interactions, clinical pharmacy, and regulation to prepare for healthcare careers. Through experiential learning, creative methods, and digital resources, the teaching methods integrate academic knowledge with practical applications. Students' critical thinking and involvement improve with collaborative learning. Quality pharmacy education is ensured by qualified instructors, research culture, and industry exposure. Faculty development programs improve teaching and research skills. Along with academic guidance, student research projects create a research mindset. Industry-academia partnership enhances students' experiences and employability through internships, cooperative research, guest lectures, and technology transfer. Specialization and transdisciplinary programs can help Indian pharmaceutical education meet industrial needs. Focusing on research-oriented learning and sponsoring research projects will boost innovation and science. The merger of AI and precision medicine will prepare graduates for the future of healthcare. Faculty development programs will keep academics current, and industry-government-academia collaboration will solve healthcare problems. Growth requires filling skill gaps, responding to the changing healthcare market, and assuring quality and consistency. Transparency, accountability, and global recognition depend on accreditation. Pharmacy education in India can produce skilled pharmacists that promote healthcare and science by addressing obstacles and embracing the future. Pharmacy education will become a cornerstone of healthcare excellence and innovation in India with ongoing stakeholder initiatives.
25
Esty, Benjamin, Bhanu Narasimhan y Peter Tufano. "Interest-rate exposure and bank mergers". Journal of Banking & Finance 23, n.º 2-4 (febrero de 1999): 255–85. http://dx.doi.org/10.1016/s0378-4266(98)00081-8.
Texto completo
26
Stephan-Recaido, Shelley C., Trevor K. Peckham, Jérôme Lavoué y Marissa G. Baker. "Characterizing the Burden of Occupational Chemical Exposures by Sociodemographic Groups in the United States, 2021". American Journal of Public Health 114, n.º 1 (enero de 2024): 57–67. http://dx.doi.org/10.2105/ajph.2023.307461.
Texto completoResumen
Objectives. To estimate the number and prevalence of workers in the United States exposed to chemical hazards available in the Canadian job-exposure matrix (CANJEM) database and examine exposure disparities across sociodemographic groups. Methods. We merged US worker demographic data from the Current Population Survey with CANJEM to characterize the burden and sociodemographic distribution of 244 chemical exposures in the United States in 2021. An interactive version of the full data set is available online ( https://deohs.washington.edu/us-exposure-burden ). Results. Of the chemical exposures examined, the most prevalent were cleaning and antimicrobial agents (14.7% of workforce estimated exposed), engine emissions (12.8%), organic solvents (12.1%), polycyclic aromatic hydrocarbons (10.1%), and diesel engine emissions (8.3%). Racial and ethnic minoritized groups, persons with lower educational attainment, foreign-born noncitizens, and males were generally overrepresented in exposure to work-related chemical hazards. Conclusions. In the United States, marginalized sociodemographic groups are estimated to experience an inequitable burden to many chemical exposures because of occupational segregation. Data from this analysis can inform occupational and public health research, policy, and interventions aimed at reducing the burden of disease and health inequities in the United States. (Am J Public Health. 2024;114(1):57–67. https://doi.org/10.2105/AJPH.2023.307461 )
27
Bhabra, Harjeet y Ashrafee Tanvir Hossain. "SOX vs C-SOX: which one works better?" Managerial Finance 44, n.º 8 (13 de agosto de 2018): 1031–46. http://dx.doi.org/10.1108/mf-03-2018-0097.
Texto completoResumen
Purpose The purpose of this paper is to analyze and compare the influence of the Sarbanes–Oxley (SOX) Act of the USA and the Canadian SOX (C-SOX) through the comparison of corporate acquisitions in these two countries. Design/methodology/approach The final sample includes 1,187 merger and tender offers undertaken by publicly traded (TSX listed) Canadian firms between 1990 and 2016. The authors use standard event study methodology (Patell, 1976) and Berkovitch and Narayanan’s (1993) seminal method to examine announcement period performance and deal motive, respectively. Findings The findings support the pro-regulation hypothesis which states that stricter regulations are more useful. Cross-listed acquirers exposed to SOX regime performed much better (both short- and long-term) than non-cross-listed counterparts with only C-SOX exposure. These findings are both statistically and economically significant. Research limitations/implications This study has direct implications as it provides evidence to the legislatures of the provinces, as well as to the federal government, that stricter regulations are effective and Canada should enact additional corporate legislation. Canada may have fared well in the past, but dynamics are changing and may further change in the future, and therefore, timely and stricter corporate legislation are more appropriate. Practical implications This study has direct implications as it provides evidence to the legislatures of the provinces, as well as to the federal government, that stricter regulations are effective and Canada should enact additional corporate legislation. Canada may have fared well in the past, but dynamics are changing and may further change in the future, and therefore, timely and stricter corporate legislation are more appropriate. Originality/value This study contributes to the growing literature of SOX-related studies. This is the first study to investigate comprehensively the differences between the two laws enacted by these neighboring countries. As USA and Canada share largely integrated capital markets and are each other’s biggest trading partner, this genre of research has great value. It is a timely study as the Canadian Federal Government is looking into standardizing corporate legislation across provinces and territories.
28
Bartram, Söhnke M., Natasha Burns y Jean Helwege. "Foreign Currency Exposure and Hedging: Evidence from Foreign Acquisitions". Quarterly Journal of Finance 03, n.º 02 (junio de 2013): 1350010. http://dx.doi.org/10.1142/s2010139213500109.
Texto completoResumen
We study the exchange rate exposures of a sample of firms that undertake large acquisitions of foreign companies. Using data from Securities and Exchange Commission (SEC) filings on their foreign operations and derivatives usage, we examine how the exposures change from before to after the acquisition. We find that these deals generally lead to reduced currency exposure, which reflects the fact that most of the firms already have business in the target's country and the mergers serve as operational hedges. In contrast, we do not find a statistically significant effect for hedging with currency derivatives despite the fact that many of the firms in the sample use such instruments.
29
Hanley, Kathleen Weiss y Gerard Hoberg. "Dynamic Interpretation of Emerging Risks in the Financial Sector". Review of Financial Studies 32, n.º 12 (19 de febrero de 2019): 4543–603. http://dx.doi.org/10.1093/rfs/hhz023.
Texto completoResumen
Abstract We use computational linguistics to develop a dynamic, interpretable methodology that can detect emerging risks in the financial sector. Our model can predict heightened risk exposures as early as mid-2005, well in advance of the 2008 financial crisis. Risks related to real estate, prepayment, and commercial paper are elevated. Individual bank exposure strongly predicts returns, bank failures, and return volatility. We also document a rise in market instability since 2014 related to sources of funding and mergers and acquisitions. Overall, our model predicts the buildup of emerging risk in the financial system and bank-specific exposures in a timely fashion. Received March 1, 2018; editorial decision November 18, 2018 by Editor Itay Goldstein.
30
Boxall, Alistair, Anthony Hardy, Sabine Beulke, Tatiana Boucard, Laura Burgin, Peter Falloon, Philip Haygarth et al. "Impacts of climate change on indirect human exposure to pathogens and chemicals from agriculture". Ciência & Saúde Coletiva 15, n.º 3 (mayo de 2010): 743–56. http://dx.doi.org/10.1590/s1413-81232010000300017.
Texto completoResumen
Climate change is likely to affect the nature of pathogens/ chemicals in the environment and their fate and transport. We assess the implications of climate change for changes in human exposures to pathogens/chemicals in agricultural systems in the UK and discuss the effects on health impacts, using expert input and literature on climate change; health effects from exposure to pathogens/chemicals arising from agriculture; inputs of chemicals/pathogens to agricultural systems; and human exposure pathways for pathogens/chemicals in agricultural systems. We established the evidence base for health effects of chemicals/pathogens in the agricultural environment; determined the potential implications of climate change on chemical/pathogen inputs in agricultural systems; and explored the effects of climate change on environmental transport and fate of various contaminants. We merged data to assess the implications of climate change in terms of indirect human exposure to pathogens/chemicals in agricultural systems, and defined recommendations on future research and policy changes to manage adverse increases in risks.
31
Khadka, Aayush y David Canning. "Understanding the Pathways from Prenatal and Post-Birth PM2.5 Exposure to Infant Death: An Observational Analysis Using US Vital Records (2011–2013)". International Journal of Environmental Research and Public Health 19, n.º 1 (27 de diciembre de 2021): 258. http://dx.doi.org/10.3390/ijerph19010258.
Texto completoResumen
We studied the relationship of prenatal and post-birth exposure to particulate matter < 2.5 μm in diameter (PM2.5) with infant mortality for all births between 2011 and 2013 in the conterminous United States. Prenatal exposure was defined separately for each trimester, post-birth exposure was defined in the 12 months following the prenatal period, and infant mortality was defined as death in the first year of life. For the analysis, we merged over 10 million cohort-linked live birth–infant death records with daily, county-level PM2.5 concentration data and then fit a Structural Equation Model controlling for several individual- and county-level confounders. We estimated direct paths from the two exposures to infant death as well as indirect paths from the prenatal exposure to the outcome through preterm birth and low birth weight. Prenatal PM2.5 exposure was positively associated with infant death across all trimesters, although the relationship was strongest in the third trimester. The direct pathway from the prenatal exposure to the outcome accounted for most of this association. Estimates for the post-birth PM2.5–infant death relationship were less precise. The results from our study add to a growing literature that provides evidence in favor of the potential harmful effects on human health of low levels of air pollution.
32
Zhou, Yilin, Ewelina Rupnik, Paul-Henri Faure y Marc Pierrot-Deseilligny. "GNSS-Assisted Integrated Sensor Orientation with Sensor Pre-Calibration for Accurate Corridor Mapping". Sensors 18, n.º 9 (24 de agosto de 2018): 2783. http://dx.doi.org/10.3390/s18092783.
Texto completoResumen
With the development of unmanned aerial vehicles (UAVs) and global navigation satellite system (GNSS), the accurate camera positions at exposure can be known and the GNSS-assisted bundle block adjustment (BBA) approach is possible for integrated sensor orientation (ISO). This study employed ISO approach for camera pose determination with the objective of investigating the impact of a good sensor pre-calibration on a poor acquisition geometry. Within the presented works, several flights were conducted on a dike by a small UAV embedded with a metric camera and a GNSS receiver. The multi-lever-arm estimation within the BBA procedure makes it possible to merge image blocks of different configurations such as nadir and oblique images without physical constraints on camera and GNSS antenna positions. The merged image block achieves a better accuracy and the sensor self-calibrated well. The issued sensor calibration is then applied to a less preferable acquisition configuration and the accuracy is significantly improved. For a corridor acquisition scene of about 600 m , a centimetric accuracy is reached with one GCP. With the provided sensor pre-calibration, an accuracy of 3.9 c m is achieved without any GCP.
33
Krengel, Maxine H. y Kimberly Sullivan. "2 1991 Gulf War Women Veterans: Neurotoxicant Exposures and Cognitive Outcomes". Journal of the International Neuropsychological Society 29, s1 (noviembre de 2023): 98–99. http://dx.doi.org/10.1017/s1355617723001893.
Texto completoResumen
Objective:The women who served in the 19901991 Persian Gulf War (GW) are unique in that they were the first group to have fewer restrictions in terms of military occupations and exposure to combat. Of the nearly 41,000 US troops who were women deployed to the GW, many were serving in frontline positions and were exposed to the same toxicants as their male counterparts. Toxicant exposures such as pesticide sprays and creams, oil well fires, diesel fuels, chemical and biological warfare (CBW) agents and anti-nerve gas (PB) pills have been found to result in cognitive impairments across a range of neuropsychological tests. Our research team has been following cohorts of women who were deployed to the GW and correlated exposures with neuropsychological outcomes. Overall, in small cohorts of women veterans we found that higher levels of exposures to pesticide sprays and creams and CBW are correlated with short-term memory, mood, and motor deficits. These findings were different from those of their male counterparts. In a recently developed data-repository we have compiled larger groups of women veterans to validate our prior findings.Participants and Methods:The current study is an analysis of data from a national bio/data-repository (Boston Biorepository Recruitment and Integrative Network for Gulf War Illness; BBRAIN) which includes key data samples from prior GW studies that have been merged and combined into retrospective datasets. Data include general health and chronic symptom questionnaires, demographics, deployment and self-reported exposure histories (separated into no exposure, fewer than 7 days exposure and greater than or equal to 7 days exposure), as well as key neuropsychological test variables. Three separate datasets were combined to include 62 women. Exposures to chemical alarms, oil well fires, pesticide cream or spray, pesticide fogging, and PB pills were self-reported. Linear regression models were produced for each continuous cognitive outcome, modeled on a given exposure, and controlling for age, education level, PTSD, and other exposures.Results:Of the 62 women, the majority were White (77%). 74% of women surveyed were employed and 55% were married. 63% of women had at least a high school education. Deployed women who had > 7 days of exposure to pesticide sprays, CBW, smoke from oil well fires, and PB pills were more likely to show deficits in the areas of verbal learning and short-term memory (p < .03) and those with exposure to CBW, smoke from oil well fires, pesticides creams and PB pills had more errors on a test of executive functioning (p < .01). These data differ from the findings from cohorts of men.Conclusions:These data validate the findings of our prior studies and add credence to the need for separate analyses for men and women. The unique outcomes may lead to individualized treatments for women veterans that may also help women with similar exposures from other deployments in addition to women with occupational exposures.
34
T, Adagashi, Idu HK, Kenneth NN y Idenyi NE. "The Inhibition Characteristics of Moringa oleifera Leaf Extract on Mild Steel in Tetraoxosulphate (VI) Acid and Sodium Hydroxide Environments". Middle East Research Journal of Engineering and Technology 3, n.º 05 (17 de octubre de 2023): 59–65. http://dx.doi.org/10.36348/merjet.2023.v03i05.002.
Texto completoResumen
The inhibiting effects of Moringa oleifera leaves extract on the corrosion of mild steel in 0.5 M and 1.0 M both of H2SO4, and NaOH solution have been investigated using weight loss techniques. A total of 72 mild steel coupons of dimensions 10 mm x 5 mm x 5 mm were suspended using nylon strings in beakers containing the media with the leaf extract, obtained by Reflux method in concentrations of 5 ml, 10 ml, 15 ml and 20 ml respectively. The setup was allowed to stand for 28 days with a coupon withdrawn from each beaker at 7 days interval for corrosion analysis. The corrosion rate profiles showed behaviors similar to those of passivating metals that begins with a steep rise in corrosion rate and progressively decreases with increasing exposure time. However, it was noticed that at an exposure time of 14 days, the coupon in the 5 ml concentration experienced a sporadic rise in corrosion rate, which we attribute to the collapse of the passive film as a result of system agitation. The inhibition efficiency of the leaf in both media was significant, suggesting that it can be used as a green and eco-friendly alternative to the synthetic and rather hazardous inhibitors in use today. In conclusion, when compared, it was established that the inhibition potentials of the leaves were better in H2SO4 than in NaOH.
35
Spill, Yannick G., Seung Joong Kim, Dina Schneidman-Duhovny, Daniel Russel, Ben Webb, Andrej Sali y Michael Nilges. "SAXS Merge: an automated statistical method to merge SAXS profiles using Gaussian processes". Journal of Synchrotron Radiation 21, n.º 1 (14 de diciembre de 2013): 203–8. http://dx.doi.org/10.1107/s1600577513030117.
Texto completoResumen
Small-angle X-ray scattering (SAXS) is an experimental technique that allows structural information on biomolecules in solution to be gathered. High-quality SAXS profiles have typically been obtained by manual merging of scattering profiles from different concentrations and exposure times. This procedure is very subjective and results vary from user to user. Up to now, no robust automatic procedure has been published to perform this step, preventing the application of SAXS to high-throughput projects. Here,SAXS Merge, a fully automated statistical method for merging SAXS profiles using Gaussian processes, is presented. This method requires only the buffer-subtracted SAXS profiles in a specific order. At the heart of its formulation is non-linear interpolation using Gaussian processes, which provides a statement of the problem that accounts for correlation in the data.
36
Baroš, Slađana y Sandra Grujičić. "Post-exposure and pre-exposure prophylaxis as HIV preventive measures". Zdravstvena zastita 51, n.º 4 (2022): 32–45. http://dx.doi.org/10.5937/zdravzast51-41701.
Texto completoResumen
HIV chemoprophylaxis started to be used since the first AIDS drug was registered, i.e. in 1987. Postexposure prophylaxis (PEP), used by persons accidentally exposed to HIV, is mostly related to professional accidental exposure to HIV (mostly among healthcare workers). It is estimated that PEP decreases HIV risk by 81%. Research and implementation of pre-exposure prophylaxis (PrEP) started about 10 years ago. PrEP is intended for use among those who are HIV negative, and in the continuous HIV risk due to their behavior. It is estimated that PrEP use decreases HIV risk by 75% or more, depending on the population and adherence to treatment. In Serbia, PEP and PrEP are still not fully regulated. However, in 2022, the work on regulations has started. In countries with unregulated PrEP, there is a risk from informal therapy use without medical supervision, which can lead to the development of resistant HIV cases among those with previously undiagnosed HIV infection. Both interventions belong to the biomedical HIV preventive interventions, and both are relevant for reaching the global AIDS target - to end AIDS as a "public health threat" by 2030. Nevertheless, for biomedical interventions to be at maximum efficacy, they have to be integrated with adequate behavioral ones, aiming to increase information, adherence to the therapy, and to periodical medical supervision, in line with defined PEP and PrEP recommendations.
37
Stellato, Francesco, Dominik Oberthür, Mengning Liang, Richard Bean, Cornelius Gati, Oleksandr Yefanov, Anton Barty et al. "Room-temperature macromolecular serial crystallography using synchrotron radiation". IUCrJ 1, n.º 4 (30 de mayo de 2014): 204–12. http://dx.doi.org/10.1107/s2052252514010070.
Texto completoResumen
A new approach for collecting data from many hundreds of thousands of microcrystals using X-ray pulses from a free-electron laser has recently been developed. Referred to as serial crystallography, diffraction patterns are recorded at a constant rate as a suspension of protein crystals flows across the path of an X-ray beam. Events that by chance contain single-crystal diffraction patterns are retained, then indexed and merged to form a three-dimensional set of reflection intensities for structure determination. This approach relies upon several innovations: an intense X-ray beam; a fast detector system; a means to rapidly flow a suspension of crystals across the X-ray beam; and the computational infrastructure to process the large volume of data. Originally conceived for radiation-damage-free measurements with ultrafast X-ray pulses, the same methods can be employed with synchrotron radiation. As in powder diffraction, the averaging of thousands of observations per Bragg peak may improve the ratio of signal to noise of low-dose exposures. Here, it is shown that this paradigm can be implemented for room-temperature data collection using synchrotron radiation and exposure times of less than 3 ms. Using lysozyme microcrystals as a model system, over 40 000 single-crystal diffraction patterns were obtained and merged to produce a structural model that could be refined to 2.1 Å resolution. The resulting electron density is in excellent agreement with that obtained using standard X-ray data collection techniques. With further improvements the method is well suited for even shorter exposures at future and upgraded synchrotron radiation facilities that may deliver beams with 1000 times higher brightness than they currently produce.
38
Xie, Shundao, Wenfang Wu, Rongjun Chen y Hong-Zhou Tan. "Reduced-Dimensional Capture of High-Dynamic Range Images with Compressive Sensing". Discrete Dynamics in Nature and Society 2020 (27 de abril de 2020): 1–13. http://dx.doi.org/10.1155/2020/6703528.
Texto completoResumen
The range of light illumination in real scenes is very large, and ordinary cameras can only record a small part of this range, which is far lower than the range of human eyes’ perception of light. High-dynamic range (HDR) imaging technology that has appeared in recent years can record a wider range of illumination than the perceptual range of the human eye. However, the current mainstream HDR imaging technology is to capture multiple low-dynamic range (LDR) images of the same scene with different exposures and then merge them into one HDR image, which greatly increases the amount of data captured. The advent of single-pixel cameras (compressive imaging system) has proved the feasibility of obtaining and restoring image data based on compressive sensing. Therefore, this paper proposes a method for reduced-dimensional capture of high dynamic range images with compressive sensing, which includes algorithms for front end (capturing) and back end (processing). At the front end, the K-SVD dictionary is used to compressive sensing the input multiple-exposure image sequence, thereby reducing the amount of data transmitted to the back end. At the back end, the Orthogonal Matching Pursuit (OMP) algorithm is used to reconstruct the input multiple-exposure image sequence. A low-rank PatchMatch algorithm is proposed to merge the reconstructed image sequence to obtain an HDR image. Simulation results show that, under the premise of reducing the complexity of the front-end equipment and the amount of communication data between the front end and the back end, the overall system achieves a good balance between the amount of calculation and the quality of the HDR image obtained.
39
Flanigan, Beverly Olson y Franklin Paul Norris. "Cross-dialectal comprehension as evidence for boundary mapping: Perceptions of the speech of southeastern Ohio". Language Variation and Change 12, n.º 2 (julio de 2000): 175–201. http://dx.doi.org/10.1017/s0954394500122033.
Texto completoResumen
Previous studies have shown that speakers have difficulty interpreting the sounds of another dialect when they are heard in isolation or reduced context, and that this difficulty is greater in areas of dialect contact where exposure to mergers or near-mergers is experienced (Labov & Ash, 1997; Labov, Karen, & Miller, 1991). A cross-dialectal comprehension test was conducted at Ohio University and three of its branch campuses. Responses were elicited to seven words digitally excerpted at three levels of reduced context from a story read by a third-generation resident of southern Ohio. Results indicated that vowel changes occurring in southern Ohio were generally interpreted by the respondents in terms of their own vowel systems, and that limited exposure to the local dialect by outsiders led to recognition only of the more salient or stereotyped sounds. Moreover, students from southern Ohio had difficulty with the same words that outsiders did, presumably reflecting semantic confusion caused by their increased exposure to other dialects. A new boundary for the South Midland dialect area is proposed on the basis of these findings.
40
Arowolo, Olatunbosun, Victoria Salemme y Alexander Suvorov. "Towards Whole Health Toxicology: In-Silico Prediction of Diseases Sensitive to Multi-Chemical Exposures". Toxics 10, n.º 12 (8 de diciembre de 2022): 764. http://dx.doi.org/10.3390/toxics10120764.
Texto completoResumen
Chemical exposures from diverse sources merge on a limited number of molecular pathways described as toxicity pathways. Changes in the same set of molecular pathways in different cell and tissue types may generate seemingly unrelated health conditions. Today, no approaches are available to predict in an unbiased way sensitivities of different disease states and their combinations to multi-chemical exposures across the exposome. We propose an inductive in-silico workflow where sensitivities of genes to chemical exposures are identified based on the overlap of existing genomic datasets, and data on sensitivities of individual genes is further used to sequentially derive predictions on sensitivities of molecular pathways, disease states, and groups of disease states (syndromes). Our analysis predicts that conditions representing the most significant public health problems are among the most sensitive to cumulative chemical exposures. These conditions include six leading types of cancer in the world (prostatic, breast, stomach, lung, colorectal neoplasms, and hepatocellular carcinoma), obesity, type 2 diabetes, non-alcoholic fatty liver disease, autistic disorder, Alzheimer’s disease, hypertension, heart failure, brain and myocardial ischemia, and myocardial infarction. Overall, our predictions suggest that environmental risk factors may be underestimated for the most significant public health problems.
41
Gopura, Sumith, Alice Ruth Payne, Laurie Buys y Deepthi Chandrika Bandara. "Fashion exposure". Journal of Fashion Marketing and Management: An International Journal 23, n.º 4 (19 de septiembre de 2019): 466–86. http://dx.doi.org/10.1108/jfmm-10-2018-0137.
Texto completoResumen
Purpose Developing countries engaged in apparel value chain are going global, seeking opportunities to upgrade the industry through providing higher value-added products and services. The purpose of this paper is to investigate how Sri Lankan apparel industry designers interact with the western fashion world in the apparel value chain process, and how they acquire, adapt and apply the knowledge needed to develop high-value fashion products in their fashion design practice. Design/methodology/approach The study adopts a qualitative approach through semi-structured interviews conducted with fashion design and product development professionals in the Sri Lankan apparel industry. An inductive thematic analysis is used in identifying participants’ experience of the western fashion world within their fashion design practice. Findings The study proposes a “fashion knowledge bridge” illustrating the ways in which Sri Lankan designers acquire and merge high-value fashion consumer culture and lifestyle knowledge with the manufacturing industry, through multisensory and virtual experience, termed “exposure”, in their interactions with the western fashion world as well as the manufacturing culture of the Sri Lankan apparel industry. Designers’ exposure improves the feasibility and reliability of their apparel products, aligning to the end-consumer needs. The study also proposes a “designers’ exposure framework” that illustrates gains made by the Sri Lankan apparel industry resulting from knowledge enhancement through the designers’ exposure. Research limitations/implications The study is based on a qualitative methodology that has potential subjective biases on the part of the researchers; in this case only the Sri Lankan designers’ perspectives were used in synthesising the findings. Originality/value The findings propose frameworks with theoretical and managerial implications for developing designers’ capabilities in apparel manufacturing countries that seek industrial upgrading through value-added fashion design practice.
42
Ramachandra, Ranjan, James C. Bouwer, Mason R. Mackey, Eric Bushong, Steven T. Peltier, Nguyen-Huu Xuong y Mark H. Ellisman. "Improving Signal to Noise in Labeled Biological Specimens Using Energy-Filtered TEM of Sections with a Drift Correction Strategy and a Direct Detection Device". Microscopy and Microanalysis 20, n.º 3 (19 de marzo de 2014): 706–14. http://dx.doi.org/10.1017/s1431927614000452.
Texto completoResumen
AbstractEnergy filtered transmission electron microscopy techniques are regularly used to build elemental maps of spatially distributed nanoparticles in materials and biological specimens. When working with thick biological sections, electron energy loss spectroscopy techniques involving core-loss electrons often require exposures exceeding several minutes to provide sufficient signal to noise. Image quality with these long exposures is often compromised by specimen drift, which results in blurring and reduced resolution. To mitigate drift artifacts, a series of short exposure images can be acquired, aligned, and merged to form a single image. For samples where the target elements have extremely low signal yields, the use of charge coupled device (CCD)-based detectors for this purpose can be problematic. At short acquisition times, the images produced by CCDs can be noisy and may contain fixed pattern artifacts that impact subsequent correlative alignment. Here we report on the use of direct electron detection devices (DDD’s) to increase the signal to noise as compared with CCD’s. A 3× improvement in signal is reported with a DDD versus a comparably formatted CCD, with equivalent dose on each detector. With the fast rolling-readout design of the DDD, the duty cycle provides a major benefit, as there is no dead time between successive frames.
43
Hwang, Myung-Jae, Jisun Sung, Miryoung Yoon, Jong-Hun Kim, Hui-Young Yun, Dae-Ryun Choi, Youn-Seo Koo, Kyungwon Oh, Sungha Yun y Hae-Kwan Cheong. "Establishment of the Korea National Health and Nutrition Examination Survey air pollution study dataset for the researchers on the health impact of ambient air pollution". Epidemiology and Health 43 (8 de febrero de 2021): e2021015. http://dx.doi.org/10.4178/epih.e2021015.
Texto completoResumen
To provide a nationwide representative dataset for the study on health impact of air pollution, we combined the data from the Korea National Health and Nutrition Examination Survey with the daily air quality and weather data by matching the date of examination and the residential address of the participants. The database of meteorological factors and air quality as sources of exposure data were estimated using the Community Multiscale Air Quality model. The linkage dataset was merged by three ways; administrative district, si-gun-gu (city, county, and district), and geocode (in latitude and longitude coordinate units) based on the participants’ residential address, respectively. During the study period, the exposure dataset of 85,018 individuals (38,306 men and 46,712 women) whose examination dates were recorded were obtained. According to the definition of exposure period, the dataset was combined with the data on short-term, mid-term, and long-term exposure to air pollutants and the meteorological indices. Calculation of the daily merged dataset’s average air pollution linked by si-gun-gu and geocode units showed similar results. This study generated a daily average of meteorological indices and air pollution exposure dataset for all regions including rural and remote areas in Korea for 11 years. It is expected to provide a platform for the researchers studying the health impact of air pollution and climate change on the representative population and area, which may facilitate the establishment of local health care plans by understanding the residents’ health status at the local as well as national level.
44
Seif, Alix E., Yimei Li, Viviane C. Cahen, Yuan-Shung V. Huang, Matt Hall, E. Anders Kolb, Brian T. Fisher, Richard Aplenc y Kelly D. Getz. "Reduced Relapse Risk in Children with Acute Myeloid Leukemia (AML) Who Experience Septic Shock (SS)". Blood 134, Supplement_1 (13 de noviembre de 2019): 3496. http://dx.doi.org/10.1182/blood-2019-122887.
Texto completoResumen
Background: Relapse remains the major clinical risk in children with AML, and persistent minimal residual disease (MRD) poses a particular therapeutic challenge as a presumably chemoresistant cell population. We previously showed innate immune stimulation can generate durable memory immune responses against leukemia cells in preclinical MRD models (Blood 2009 114:2459; Leukemia 2018 32: 539). These treatments mimic the "danger" signal provided by SS and may offer novel immunotherapeutic approaches for patients who fail or are not eligible for targeted immunotherapies. Demonstrating a protective effect of SS against AML relapse would support clinical development of innate immune stimulants. We hypothesized 1) SS is associated with a decreased risk of AML relapse among children who were able to achieve remission after induction, and 2) this effect is most pronounced in children with persistent MRD, who are more likely to have both SS exposures and relapses. Methods: We used a previously assembled cohort of children with de novo AML using Pediatric Health Information System (PHIS) data merged with patients on two clinical trials from the Children's Oncology Group (COG; PLOS One 2015 10:e0143480). We developed and validated a method to detect SS exposures in PHIS using vasopressor billing codes (PBC 2019 10.1002/pbc.27713 #2024) and used COG data for demographics, treatment, and outcomes. SS exposures were captured starting 7 days from first chemotherapy until last day of the last treatment course or 30 days prior to relapse. Follow-up for relapse and non-relapse mortality (NRM) began after the end of Induction II and continued to last contact, off-study date, or until 5 years from diagnosis. Cumulative incidences of relapse (CIR) and NRM (CIN) were estimated treating each other as competing risks. Sub-distribution hazard regression models were used to estimate crude and adjusted sub-hazard ratios (subHR) and associated 95% confidence intervals (CI) of relapse in relation to SS. SS was treated as a time-varying exposure, so each patient became SS-exposed once the first SS occurred. Demographic and clinical characteristics were evaluated as potential confounders of the associations of interest. Results: We identified 569 COG-PHIS patients with AML who achieved complete remission by the end of Induction II. In this cohort, 188 (33%) experienced SS during therapy. Older age, Black non-Hispanic race-ethnicity, Hispanic ethnicity, and receipt of stem cell transplant (SCT) were associated with SS exposure (Table 1). Median follow-up was 1122 days (IQR 413-1745) from the end of Induction II. Relapse occurred in 220 (38.7%) patients and was associated with male sex and genetic risk (Table 1). Positive end-Induction I MRD approached a significant association with relapse. CIRs were similar among SS-exposed and unexposed patients in the overall cohort and in MRD-negative patients (Figs. 1A-B). Among children with persistent MRD, SS-exposed patients had a lower 5-year CIR than unexposed patients (43% vs. 60.1%; Fig. 1C). Adjusted subHR for relapse for the overall cohort was 0.82 (CI: 0.61-1.11); for the MRD-negative subgroup, adjusted subHR was 0.86 (CI: 0.61-1.21); and for the MRD-positive subgroup, 0.57 (CI: 0.31-1.05). These effects were consistently in the protective direction but did not reach statistical significance. In a sensitivity analysis restricting duration of the exposure effect to 12 months, SS exposure in the overall cohort was associated with a risk reduction (adjusted subHR 0.65; CI: 0.45-0.92). NRM occurred in 28 (4.9%) and was associated with high-risk therapy on AAML1031 and with positive MRD, with a near-significant association with SCT (not shown). SS-exposed patients had a higher 5-year CIN (10.4% v. 2.8%; Fig. 1D). Conclusions: Using merged clinical trial and administrative data, we identified a potentially protective effect of exposure to a strong immune stimulus (SS) that was most pronounced in children with persistent MRD. This suggests immune surveillance for low-level AML can be induced and supports investigation of innate immune stimulant therapy for this very poor prognosis childhood leukemia. While NRM is higher among SS-exposed patients, clinical trials of innate immune stimulants would comprise controlled interventions expected to result in markedly less toxicity than unpredictable SS exposures. Repeated dosing may prolong the effect duration beyond 12 months. Disclosures Fisher: Merck: Research Funding; Pfizer: Research Funding; Astellas: Other: Data Safety Monitoring Board Chair for an antifungal study.
45
Carpenter, Chris. "Study Examines Incremental Method vs. Split Conditions in Reserves Booking". Journal of Petroleum Technology 73, n.º 12 (1 de diciembre de 2021): 35–36. http://dx.doi.org/10.2118/1221-0035-jpt.
Texto completoResumen
This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 206104, “Incremental Method vs. Split Conditions: Discussing the Similarities Between Reserves Evaluation and a Madoff Scheme,” by Dominique Salacz, SPE, and Farid Allam, SPE, ADNOC, and Imre Szilagyi, Eötvös Loránd University, et al., prepared for the 2021 SPE Annual Technical Conference and Exhibition, Dubai, 21–23 September. The paper has not been peer reviewed. After the oil-price crashes of 2014 and 2020, several merger and acquisition deals ended in litigation because operators canceled major projects or infills wells that were booked in “probable” reserves only. In the complete paper, the authors challenge the compatibility between the deterministic incremental reserve assessment method and the concept of split condition, which is not allowed for reserves booking under the Petroleum Resources Management System (PRMS). With some examples, the authors argue that the incremental method may mislead investors if used wrongly. The Two Approaches PRMS is a simple, fit-for-purpose system. However, it still allows for reporting volumes under slightly different methods that may lead to very different results based on the definition adopted for the “project” by the evaluator. The text of the PRMS is quoted extensively in the complete paper in defining these methods. The authors write that the deterministic incremental method seems to be favored by evaluators educated under, or heavily exposed to, pre-2010 US Securities and Exchange Commission regulations, in which proved reserves were only disclosed. Under this approach, the term “proven” generally refers to recoverable volumes expected from the partition of the reservoir with a high degree of confidence related to the high level of geological knowledge. The authors also write that the deterministic scenario method, on the other hand, evidently is favored by evaluators and engineers with less exposure to the pre-2010 guidelines. This method provides three estimates (low, best, and high) for every individual project. Comparing the Two Methods The study-case accumulation is defined by a simple structural trap controlled by a top seal and a fault on the western side of the asset (Fig. 2 of the complete paper). Oil has been discovered by Well W1, which hit the permeable top at 9,695 ft near the structure’s crest. For mechanical reasons, drilling operations were stopped and the lowest known hydrocarbon sets the oil down to (ODT) at 9,785 ft, providing a discovered oil column of 90 ft. Horizontal Well WH2 was drilled into the discovered reservoir partition. Today, Well WH2 is the only producing well of the accumulation. Well W1 will be reperforated during a workover to produce the attic oil of the reservoir. Because the well did not reach the aquifer, a major uncertainty for further development is assigned to oil/water contact (OWC) position. At the current stage of resource maturation, up to 11 additional wells are considered.
46
Guo, Hengyuan, Xingying Jia y Junwei Li. "Analysis on Motivation and Risk of E-commerce M&A: Alibaba's Acquisition of Sun Art Retail". BCP Business & Management 47 (10 de julio de 2023): 139–44. http://dx.doi.org/10.54691/bcpbm.v47i.5184.
Texto completoResumen
With the rapid development of e-commerce in China, the competition among enterprises in the market is becoming increasingly fierce. Many enterprises try to obtain competitive advantages in the market and reduce the risk exposure through mergers and acquisitions. However, corporate mergers and acquisitions is a complex activity and there exists various risks in the process, e.g., financial risk, which directly affects the success of M&A and the development of enterprises after M&A. Based on the case of Alibaba's acquisition of Sun Art Retail, this paper investigates the possible risks of M&A based on motivation analysis and performance analysis. According to the analysis, the acquisition of Sun Art Retail in the short term has brought great growth ability to the profitability of Alibaba, but reduced the debt solvency of Alibaba as well. Given the result of the analysis, this study provides three main measures to manage risks and improve the risk management capability. Overall, these results shed light on guiding further exploration of e-commerce mergers and acquisitions and the new retail model.
47
Ágoston, Dóra, Csilla Hánis, Henriette Ócsai, Ildikó Csányi, Erika Varga, Irma Korom, István Németh et al. "Multimodal treatment options for Merkel cell carcinoma". Bőrgyógyászati és Venerológiai Szemle 98, n.º 5 (11 de noviembre de 2022): 240–46. http://dx.doi.org/10.7188/bvsz.2022.98.5.1.
Texto completoResumen
Merkel cell carcinoma is a rare neuroendocrine skin tumor with an aggressive behavior. The clonal integration of the Merkel cell polyomavirus and the UV light can be highlighted in its pathogenesis. Risk factors for its development are advanced age, chronic UV exposure, caucasian skin type, male gender, and immunosuppression. The disease is prone to rapid progression and the prognosis is unfavorable. In its treatment, surgical removal of the primary tumor and biopsy of the sentinel lymph node, as well as adjuvant radiation therapy, are of particular importance. Among the systemic treatments, immune checkpoint inhibitors are recommended as the first line. The authors discuss the latest European guideline for the diagnosis and the treatment.
48
Liu, Jie y Yuanyuan Peng. "Research on Image Enhancement Algorithm Based on Artificial Intelligence". Journal of Physics: Conference Series 2074, n.º 1 (1 de noviembre de 2021): 012024. http://dx.doi.org/10.1088/1742-6596/2074/1/012024.
Texto completoResumen
Abstract With the continuous development of social science and technology, people have higher and higher requirements for image quality. This paper integrates artificial intelligence technology and proposes a low-illuminance panoramic image enhancement algorithm based on simulated multi-exposure fusion. First, the image information content is used as a metric to estimate the optimal exposure rate, and the brightness mapping function is used to enhance the V component, and the low-illuminance. The image and the overexposed image are input, the medium exposure image is synthesized by the exposure interpolation method, and the low illumination image, the medium exposure image and the overexposure image are merged using a multi-scale fusion strategy to obtain the fused image, which is corrected by a multi-scale detail enhancement algorithm. After the fusion, the details are enhanced to obtain the final enhanced image. Practice has proved that the algorithm can effectively improve the image quality.
49
Allen, Julie Ober, Briana Mezuk, Tomohiro Ko, Jane Rafferty, Jamie Abelson, Viktoryia Kalesnikava y James Jackson. "Mechanisms of Cardiometabolic Disparities: Stressor Characteristics Linked to HPA-Axis Dysregulation". Innovation in Aging 4, Supplement_1 (1 de diciembre de 2020): 573. http://dx.doi.org/10.1093/geroni/igaa057.1900.
Texto completoResumen
Abstract Diurnal cortisol slopes are stress-sensitive HPA-axis biomarkers implicated in cardiometabolic health outcomes and disparities. This study used two longitudinal cohort studies (CREATE and TRIAD) with harmonized variables to comprehensively examine what types of exposure to stressors are most salient for cortisol dysregulation in later life, and whether the characteristics of stressor exposure accounts for Black-White disparities in cortisol dysregulation (merged sample N=209, 65% male, mean age 61, 17% Black). Black participants reported greater stressor exposure than Whites along some dimensions (e.g., # recent major stressors, appraised severity of lifetime stressors, all p<.02) but comparable exposure in others (e.g., # of lifetime stressors and life domains). Stressor exposure measures that captured psychological components (i.e., appraised severity, psychological distress) and pervasiveness (i.e., # life domains with major stressors) were more closely related to cortisol dysregulation than more objective measures (e.g., # of recent /lifetime stressors). Everyday discrimination was associated with racial disparities.
50
Elgarten, Caitlin W., Yimei Li, Yuan-Shung V. Huang, Richard Aplenc, Michael T. Hemmer, Mukta Arora, Stephen R. Spellman et al. "Early Broad-Spectrum Antibiotics and Risk of Acute Graft-Versus-Host Disease in Children: An Analysis from the Center for International Blood and Marrow Transplantation Research (CIBMTR) and the Pediatric Health Information System (PHIS)". Blood 134, Supplement_1 (13 de noviembre de 2019): 599. http://dx.doi.org/10.1182/blood-2019-130466.
Texto completoResumen
Background Variation in the gastrointestinal microbiota after hematopoietic cell transplantation (HCT) has been associated with acute graft-versus-host disease (aGVHD). The significant immunosuppression associated with HCT leads to frequent broad-spectrum antibiotic exposures that in turn drive host microbiota composition. We sought to explore the association of different antipseudomonal antibiotic classes, commonly administered as empiric therapy for neutropenic fever, with subsequent aGVHD-risk in a large, multicenter cohort of children undergoing HCT for acute leukemia. We hypothesized that antibiotic classes that retain broad anti-anaerobic activity would increase aGVHD due to the greater potential impact of these agents on the microbiota. Methods Children 1-21 years old who underwent first HCT for acute leukemia from 2004 to 2017 were identified in 2 databases: CIBMTR, an observational database with demographic, transplant and outcomes information, and PHIS, an administrative database with resource utilization data from freestanding children's hospitals. Patients were then merged based on date of birth, date of transplant, sex and disease. The outcome was grade 2-4 aGVHD by day +100. The primary exposures were 3 distinct classes of antibiotics commonly used for empiric therapy: (1) antipseudomonal cephalosporins, (2) antipseudomonal penicillins and (3) carbapenems. They were captured as days of therapy from conditioning start to day +7, and classified as no, low (1-3 days), or high (>3 days) exposure. Logistic regression was applied to evaluate the association between aGVHD and each exposure, controlling for exposure to the other two classes. For the subset of patients with data on date of GVHD onset, a time to event analysis was performed considering death without GVHD as a competing event. For both analyses, we constructed multivariable models that were informed by a directed acyclic graph and included covariates representing demographics, transplant characteristics and GVHD risk factors associated with both exposure and outcome. The adjusted models also included exposure to other antibiotics within the same window, captured as fluoroquinolones, intravenous vancomycin and other adjunctive antibiotics, with and without anti-anaerobic activity. Generalized estimating equations with robust variance estimates were employed to account for clustering at the hospital level. Results The assembled cohort included 2,501 patients at 35 hospitals. One-third of patients (36.6%) developed aGVHD, 4.4% died without GVHD and no patients were lost to follow-up. The proportion of patients exposed to at least 1 day of an antipseudomonal cephalosporin was 52.2%, but was lower for antipseudomonal penicillins (24.1%) and carbapenems (18.2%). Table 1 shows patient characteristics by exposure to the antibiotic classes of interest. The unadjusted and adjusted associations between the three antibiotic classes and aGVHD are shown in table 2. In the unadjusted model, high exposure to cephalosporins and carbapenems was statistically associated with increased aGVHD risk. For antipseudomonal penicillins, the direction of association was the same but not statistically significant. After adjustment, most point estimates reverted towards the null. The time to event analysis included 1,146 patients that were similar to the overall cohort with a similar incidence of aGVHD (35.5%) diagnosed a median of 28 (range: 8-100) days after HCT. This group had a higher proportion of mismatched donors (40.9 vs 30.2%), cord blood transplants (40.0 vs 23.5%) and receipt of growth factors (50.5% vs 38.9%). Table 2 also shows the unadjusted and adjusted associations for this analysis. As above, the unadjusted point estimates of association between cephalosporins and carbapenems and aGVHD were suggestive of an association but reverted towards the null with adjustment. Conclusions After controlling for other antibiotic exposures and GHVD-risk factors, there was not a statistically significant association between antibiotic exposure and aGVHD for any of three antibiotic classes commonly used for empiric therapy. However, the adjusted point estimates suggest exposure to carbapenems may confer some additional aGHVD risk. Further exploration of different exposure windows is planned to understand if the identified associations change with capture of earlier or later antibiotic exposures. Disclosures Jagasia: Kadmon: Consultancy; Incyte: Consultancy; Janssen: Research Funding. MacMillan:Alpine Immune Sciences: Consultancy; Angiocrine: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy; Equillium: Membership on an entity's Board of Directors or advisory committees. Fisher:Pfizer: Research Funding; Astellas: Other: Data Safety Monitoring Board Chair for an antifungal study; Merck: Research Funding.