239 research outputs found
Using DEA to estimate the importance of objectives for decision makers
In this paper we establish further connections between DEA and Multi-criteria Decision Analysis by suggesting a particular way to estimate preference weights for different objectives using DEA. We claim that the virtual multipliers obtained from a standard DEA model are not suitable to measure the preferences of a decision maker. Our suggestion takes advantage of the parallelism between DEA and the methodology proposed by Sumpsi et al. (1997) by projecting each unit on a linear combination of the elements of the pay-off matrix. Finally, we make an application of the proposed methodology to agricultural economics in a case study with Spanish data.Data Envelopment Analysis, Multicriteria Decision Analysis, preferences, weights, virtual multipliers.
Using a modified DEA model to estimate the importance of objectives. An application to agricultural economics.
This paper shows a connection between Data Envelopment Analysis (DEA) and the methodology proposed by Sumpsi et al. (1997) to estimate the weights of objectives for decision makers in a multiple attribute approach. This connection gives rise to a modified DEA model that allows to estimate not only efficiency measures but also preference weights by radially projecting each unit onto a linear combination of the elements of the payoff matrix (which is obtained by standard multicriteria methods). For users of Multiple Attribute Decision Analysis the basic contribution of this paper is a new interpretation of the methodology by Sumpsi et al. (1997) in terms of efficiency. We also propose a modified procedure to calculate an efficient payoff matrix and a procedure to estimate weights through a radial projection rather than a distance minimization. For DEA users, we provide a modified DEA procedure to calculate preference weights and efficiency measures which does not depend on any observations in the dataset. This methodology has been applied to an agricultural case study in Spain.Multicriteria Decision Making, Goal Programming, Weights, Preferences, Data Envelopment Analysis.
Accounting for rupture directivity in ShakeMap
The rapid and accurate information about the ground shaking following an earthquake is necessary for
emergency response planning. A prompt strategy is contouring the real data recorded at the stations.
However only few regions, i.e. Japan and Taiwan, have an instrumental coverage as good as needed to
produce shaking maps relying almost entirely on real data. ShakeMap has been conceived in order to
“fill” the data gap and producing stable contouring using the ground motion predictive equations
(GMPEs) and site effect. Thus for regions where the data coverage is sparse, the interpolation plays a
crucial role and the choice of the GMPE can affect strongly the goodness of the ground shaking
estimation. However the GMPEs derive from an empirical regression describing the averaged behavior
of the ground shaking and tend to mask, when present, specific trends due to multidimensional effects
like the asymmetry of the rupture process (directivity effect). Thus, ShakeMaps for large events may
not reproduce faithfully the ground motion in the near source if determined without the introduction of
rupture related parameters.
One way to improve the ShakeMap prediction is to modify the ground motion modeling in order to
better explain the ground motion variability. To this purpose, the empirical model can be refined with
information about the rupture process (Spagnuolo PhD2010), in this case using the directivity term
defined by Spudich and Chiou (Earthquake Spectra 2008).
The aim of this work is to quantify the effectiveness of refined GMPEs in improving the performance
of ShakeMap. We quantify the agreement of this new GMPE with the real recorded data, and make
inference about the reliability of this new ShakeMap. The test is focused on the study of the ShakeMap
degradation when the number of the observations is reduced, and on the quantification of the
improvements due to the directivity term. In order to conduct properly the test, we investigate two well-
recorded events from Japan: the 2008 Iwate-Miyagi (M7) and the 2000 Tottori (M6.6) events.
This work is part of the DPC-INGV S3 project (2007-09), as described in the companion abstract
Ameri et al. (ESC2010)
Outbreak of Endophthalmitis After Cataract Surgery: The Importance of the Quality of the Surgical Wound
Postoperative endophthalmitis is a rare but potentially devastating condition. We investigated an outbreak of 8 cases of endophthalmitis in patients who underwent phakectomy performed by a single surgeon from January through September 2004. The outbreak was traced to damaged surgical blades, and it highlights the importance of the quality of the surgical woun
A modified DEA model to estimate the importance of objectives with an application to agricultural economics
This paper demonstrates a connection between Data Envelopment Analysis (DEA) and a non-interactive elicitation method to estimate the weights of objectives for decision-makers in a multiple-attribute approach. This connection gives rise to a modified DEA model that allows us to estimate not only efficiency measures but also preference weights by radially projecting each unit onto a linear combination of the elements of the payoff matrix (which is obtained by standard multicriteria methods). For users of Multiple Attribute Decision Analysis the basic contribution of this paper is a new interpretation in terms of efficiency of the non-interactive methodology employed to estimate weights in a multicriteria approach. We also propose a modified procedure to calculate an efficient payoff matrix and a procedure to estimate weights through a radial projection rather than a distance minimisation. For DEA users, we provide a modified DEA procedure to calculate preference weights and efficiency measures that does not depend on any observations in the dataset. This methodology has been applied to an agricultural case study in Spain.DEPARTMENT OF BUSINESS ADMINISTRATION AND MARKETINGPostprin
Type 2 diabetes mellitus and osteoarthritis
Objectives: Type 2 diabetes mellitus (T2DM) and osteoarthritis (OA) are common diseases that frequently co-exist, along with overweight/obesity. While the mechanical impact of excess body weight on joints may explain lower limb OA, we sought to explore whether T2DM is linked to OA outside of excess weight and whether T2DM may play a role in OA pathophysiology. The consequence of T2DM on OA outcomes is a question of research interest. Methods: We conducted a critical review of the literature to explore the association between T2DM and OA, whether any association is site-specific for OA, and whether the presence of T2DM impacts on OA outcomes. We also reviewed the literature to assess the safety of anti-OA treatments in patients with T2DM. Results: T2DM has a pathogenic effect on OA through 2 major pathways involving oxidative stress and low-grade chronic inflammation resulting from chronic hyperglycemia and insulin resistance. T2DM is a risk factor for OA progression and has a negative impact on arthroplasty outcomes. Evidence is mounting for safety concerns with some of the most frequently prescribed anti-OA medications, including paracetamol, non-steroidal anti-inflammatory drugs, and corticosteroid injections, while other anti-OA medications may be safely prescribed in OA patients with T2DM, such as glucosamine and intra-articular hyaluronic acid. Conclusions: Future research is needed to better understand whether diabetes control and prevention can modulate OA occurrence and progression. The selection of therapy to treat OA symptoms in patients with T2DM may require careful consideration of the evidence based to avoid untoward safety issues.The meeting was funded by the ESCEO, a Belgian not-for-profit organization.
The authors thank the Chair for Biomarkers of Chronic Diseases
and the International Scientific Partnership Program (ISPP#0111) at
King Saud University, Riyadh, Saudi Arabia for their suppor
Developments in physics of massive stars
New constraints on stellar models are provided by large surveys of massive
stars, interferometric observations and asteroseismology. After a review of the
main results so far obtained, we present new results from rotating models and
discuss comparisons with observed features. We conclude that rotation is a key
feature of massive star physics.Comment: 13 pages, 10 figures, IAU Symp. 250, Massive stars as Cosmic Engines,
F. Bresolin, P.A. Crowther, J. Puls Ed
Association between Genetic Variants in NOS2 and TNF Genes with Congenital Zika Syndrome and Severe Microcephaly
Zika virus (ZIKV) causes Congenital Zika Syndrome (CZS) in individuals exposed prenatally. Here, we investigated polymorphisms in VEGFA, PTGS2, NOS3, TNF, and NOS2 genes as risk factors to CZS. Forty children with CZS and forty-eight children who were in utero exposed to ZIKV infection, but born without congenital anomalies, were evaluated. Children with CZS were predominantly infected by ZIKV in the first trimester (p < 0.001) and had mothers with lower educational level (p < 0.001) and family income (p < 0.001). We found higher risk of CZS due the allele rs2297518[A] of NOS2 (OR = 2.28, CI 95% 1.17–4.50, p = 0.015). T allele and TT/CT genotypes of the TNF rs1799724 and haplotypes associated with higher expression of TNF were more prevalent in children with CZS and severe microcephaly (p = 0.029, p = 0.041 and p = 0.030, respectively). Our findings showed higher risk of CZS due ZIKV infection in the first trimester and suggested that polymorphisms in NOS2 and TNF genes affect the risk of CZS and severe microcephaly
Microcephaly prevalence after the 2015 to 2016 Zika outbreak in Tangará da Serra, Brazil: a population-based study
Objective: Prenatal infection with the Zika virus (ZIKV) can lead to congenital Zika syndrome (CZS), characterized by microcephaly and brain injury. However, there are questions regarding the prevalence of microcephaly/CZS after the ZIKV outbreak in defined geographic areas. This study aimed to identify adverse outcomes in live births of fetuses exposed in utero to the ZIKV, compared to unexposed births, as well as maternal sociodemographic, delivery, and birth characteristics. Methods: Here, we conducted a cross-sectional observational study to investigate the characteristics of all live births in the city of Tangará da Serra, Mato Grosso, Brazil, in 2016, after the outbreak of ZIKV infection in late 2015. All live births of children to women residing in the municipality of Tangará da Serra between January 1 and December 31, 2016, were evaluated, and head circumference was measured at birth and after 24 hours. Children born with microcephaly or a maternal history of confirmed or suspected prenatal ZIKV infection were evaluated by a multidisciplinary team. The outcomes of the exposed and non-exposed children were compared. Prevalence ratios and their respective 95% confidence intervals were calculated for sociodemographic, delivery, and live birth characteristics. Results: Of 1,441 live births, 106 (7.3%) were from mothers with confirmed or highly probable exposure to ZIKV. The prevalence of severe congenital microcephaly (41.7/10,000) in Tangará da Serra in 2016 was ten-fold higher than that in Latin America before 2015. Conclusion: This study may serve as a model to investigate possible outbreaks of infections in a defined geographical space in the future
Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope
The ANTARES telescope is well-suited for detecting astrophysical transient
neutrino sources as it can observe a full hemisphere of the sky at all times
with a high duty cycle. The background due to atmospheric particles can be
drastically reduced, and the point-source sensitivity improved, by selecting a
narrow time window around possible neutrino production periods. Blazars, being
radio-loud active galactic nuclei with their jets pointing almost directly
towards the observer, are particularly attractive potential neutrino point
sources, since they are among the most likely sources of the very high-energy
cosmic rays. Neutrinos and gamma rays may be produced in hadronic interactions
with the surrounding medium. Moreover, blazars generally show high time
variability in their light curves at different wavelengths and on various time
scales. This paper presents a time-dependent analysis applied to a selection of
flaring gamma-ray blazars observed by the FERMI/LAT experiment and by TeV
Cherenkov telescopes using five years of ANTARES data taken from 2008 to 2012.
The results are compatible with fluctuations of the background. Upper limits on
the neutrino fluence have been produced and compared to the measured gamma-ray
spectral energy distribution.Comment: 27 pages, 16 figure
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