908 research outputs found
Analysing The Efficiency Of Portuguese Pension Funds:A Stochastic Frontier Model
This paper examines technical efficiency of Portuguese pension funds management companies, using a stochastic frontier model in order to obtain estimates of economies of scale and scope. The empirical findings reveal a significant effect of efficiency measures on pension funds efficiency. Their implications for managers and policy makers are discussed
The Chances to Produce and Detect the b-b-ubar-dbar Tetraquark at LHC
In the LHC collider a significant rate of events with double parton
scattering is expected. This will be the leading mechanism for production of
two b-bbar pairs. We estimate the probability of binding two b quarks into a
diquark and the probability of dressing this diquark into a b-b-ubar-dbar
ISP=01+ tetraquark. Calculations shows that that this bound state of two B
mesons is stable against the strong interaction and has a life time of the
order of ps. We estimate that the production rate at luminosity L=0.1 events
per second will be about 6 tetraquarks per hour or more.Comment: Contributed talk at the XVIII European Conference on Few-Body
Problems in Physics, September 8-14, Bled, Slovenia, 4 pages LaTe
Amiloidosis cardiaca secundaria a macroglobulinemia de waldenström
Introduction: Waldenström's macroglobulinemia is a hematological neoplasm belonging to the group of monoclonal gammopathies, which includes systemic symptoms and those related to an increase in M paraprotein. Objective: To describe a case of cardiac amyloidosis associated with macroglobulinemia. Clinical case: Male patient who was admitted for asthenia, dysphonia, and who, during his evolution, developed progressive dyspnea, heart failure and pleural effusion. Additionally, echocardiography showed myocardial granular pattern, while pleural biopsy was positive for Congo red staining. Subsequently, he received treatment with bortezomib, dexamethasone and rituximab, with favorable evolution. Conclusions: In this disease, early diagnosis is an important advantage for survival. Therefore, its management is palliative of cardiac manifestations. The present case shows a diagnostic challenge, in which the less frequent etiologies of heart failure must be taken into account.Revisión por pare
Μulti-institutional dosimetric delivery assessment of intracranial stereotactic radiosurgery on different treatment platforms
BACKGROUND AND PURPOSE: Assessment of dosimetric accuracy of radiosurgery on different treatment platforms. MATERIAL AND METHODS: Thirty-three single fraction treatment plans were assessed at thirty centres using an anthropomorphic head phantom with target and brainstem structures. The target being a single irregular shaped target, ∼8cc, 10 mm from the brainstem. The phantom was "immobilised", scanned, planned and treated following the local protocols. EBT-XD films and alanine pellets were used to measure absolute dose, inside both the target and the brainstem, and compared with TPS predicted dose distributions. RESULTS: PTV alanine measurements from gantry-based linacs showed a median percentage difference to the TPS of 0.65%. Cyberknife (CK) had the highest median difference of 2.3% in comparison to the other platforms. GammaKnife (GK) showed the smallest median of 0.3%. Similar trends were observed in the OAR with alanine measurements showing median percentage differences of1.1%, 2.0% and 0.4%, for gantry-based linacs, CK and GK respectively. All platforms showed comparable gamma passing rates between axial and sagittal films. CONCLUSIONS: This comparison has highlighted the dosimetric variation between measured and TPS calculated dose for each delivery platforms.. The results suggest that clinically acceptable agreement with the predicted dose distributions is achievable by all treatment delivery systems. Radiosurgery, Dosimetry, End-to-end, Audit, Anthropomorphic Phantom, Alanine, Radiochromic film
Establishing ZIF-8 as a reference material for hydrogen cryoadsorption: An interlaboratory study
Hydrogen storage by cryoadsorption on porous materials has the advantages of low material cost, safety, fast kinetics, and high cyclic stability. The further development of this technology requires reliable data on the H2 uptake of the adsorbents, however, even for activated carbons the values between different laboratories show sometimes large discrepancies. So far no reference material for hydrogen cryoadsorption is available. The metal-organic framework ZIF-8 is an ideal material possessing high thermal, chemical, and mechanical stability that reduces degradation during handling and activation. Here, we distributed ZIF-8 pellets synthesized by extrusion to 9 laboratories equipped with 15 different experimental setups including gravimetric and volumetric analyzers. The gravimetric H2 uptake of the pellets was measured at 77 K and up to 100 bar showing a high reproducibility between the different laboratories, with a small relative standard deviation of 3–4 % between pressures of 10–100 bar. The effect of operating variables like the amount of sample or analysis temperature was evaluated, remarking the calibration of devices and other correction procedures as the most significant deviation sources. Overall, the reproducible hydrogen cryoadsorption measurements indicate the robustness of the ZIF-8 pellets, which we want to propose as a reference material.M. Maiwald, J. A. Villajos, R. Balderas and M. Hirscher acknowledge the EMPIR programme from the European Union's Horizon 2020 research and innovation programme for funding. F. Cuevas and F. Couturas acknowledge support from France 2030 program under project ANR-22-PEHY-0007. D. Cazorla and A. Berenguer-Murcia thank the support by PID2021-123079OB-I00 project funded by MCIN/AEI/10.13039/501100011033, and “ERDF A way of making Europe”. K. N. Heinselman, S. Shulda and P. A. Parilla acknowledge the support from the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Hydrogen and Fuel Cell Technology Office through the HyMARC Energy Materials Network
Effects of an enzymatically stable C-terminal hexapseudopeptide fragment peptide of xenin-25, psi-xenin-6, on pancreatic islet function and metabolism
Generating fuzzy rules by learning from olive tree transpiration measurement - An algorithm to automatize Granier sap flow data analysis
The present study aims at developing an intelligent system of automating data analysis and prediction
embedded in a fuzzy logic algorithm (FAUSY) to capture the relationship between environmental variables
and sap flow measurements (Granier method). Environmental thermal gradients often interfere
with Granier sap flow measurements since this method uses heat as a tracer, thus introducing a bias in
transpiration flux calculation. The FAUSY algorithm is applied to solve measurement problems and provides
an approximate and yet effective way of finding the relationship between the environmental variables
and the natural temperature gradient (NTG), which is too complex or too ill-defined for precise
mathematical analysis. In the process, FAUSY extracts the relationships from a set of input–output environmental
observations, thus general directions for algorithm-based machine learning in fuzzy systems
are outlined. Through an iterative procedure, the algorithm plays with the learning or forecasting via a
simulated model. After a series of error control iterations, the outcome of the algorithm may become
highly refined and be able to evolve into a more formal structure of rules, facilitating the automation
of Granier sap flow data analysis. The system presented herein simulates the occurrence of NTG with reasonable
accuracy, with an average residual error of 2.53% for sap flux rate, when compared to data processing
performed in the usual way. For practical applications, this is an acceptable margin of error given
that FAUSY could correct NTG errors up to an average of 76% of the normal manual correction process. In
this sense, FAUSY provides a powerful and flexible way of establishing the relationships between the
environment and NTG occurrencesinfo:eu-repo/semantics/publishedVersio
Maternal and perinatal health research priorities beyond 2015 : an international survey and prioritization exercise
Background: Maternal mortality has declined by nearly half since 1990, but over a quarter million women still die every year of causes related to pregnancy and childbirth. Maternal-health related targets are falling short of the 2015 Millennium Development Goals and a post-2015 Development Agenda is emerging. In connection with this, setting global research priorities for the next decade is now required.
Methods. We adapted the methods of the Child Health and Nutrition Research Initiative (CHNRI) to identify and set global research priorities for maternal and perinatal health for the period 2015 to 2025. Priority research questions were received from various international stakeholders constituting a large reference group, and consolidated into a final list of research questions by a technical working group. Questions on this list were then scored by the reference working group according to five independent and equally weighted criteria. Normalized research priority scores (NRPS) were calculated, and research priority questions were ranked accordingly. Results: A list of 190 priority research questions for improving maternal and perinatal health was scored by 140 stakeholders. Most priority research questions (89%) were concerned with the evaluation of implementation and delivery of existing interventions, with research subthemes frequently concerned with training and/or awareness interventions (11%), and access to interventions and/or services (14%). Twenty-one questions (11%) involved the discovery of new interventions or technologies. Conclusions: Key research priorities in maternal and perinatal health were identified. The resulting ranked list of research questions provides a valuable resource for health research investors, researchers and other stakeholders. We are hopeful that this exercise will inform the post-2015 Development Agenda and assist donors, research-policy decision makers and researchers to invest in research that will ultimately make the most significant difference in the lives of mothers and babies.</p
System Size and Energy Dependence of Jet-Induced Hadron Pair Correlation Shapes in Cu+Cu and Au+Au Collisions at sqrt(s_NN) = 200 and 62.4 GeV
We present azimuthal angle correlations of intermediate transverse momentum
(1-4 GeV/c) hadrons from {dijets} in Cu+Cu and Au+Au collisions at sqrt(s_NN) =
62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is
broadened, non-Gaussian, and peaked away from \Delta\phi=\pi in central and
semi-central collisions in all the systems. The broadening and peak location
are found to depend upon the number of participants in the collision, but not
on the collision energy or beam nuclei. These results are consistent with sound
or shock wave models, but pose challenges to Cherenkov gluon radiation models.Comment: 464 authors from 60 institutions, 6 pages, 3 figures, 2 tables.
Submitted to Physical Review Letters. Plain text data tables for the points
plotted in figures for this and previous PHENIX publications are (or will be)
publicly available at http://www.phenix.bnl.gov/papers.htm
Transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at sqrt(s_NN)=200 GeV: Jet-quenching and the response of partonic matter
Azimuthal angle \Delta\phi correlations are presented for charged hadrons
from dijets for 0.4 < p_T < 10 GeV/c in Au+Au collisions at sqrt(s_NN) = 200
GeV. With increasing p_T, the away-side distribution evolves from a broad to a
concave shape, then to a convex shape. Comparisons to p+p data suggest that the
away-side can be divided into a partially suppressed "head" region centered at
Delta\phi ~ \pi, and an enhanced "shoulder" region centered at Delta\phi ~ \pi
+/- 1.1. The p_T spectrum for the "head" region softens toward central
collisions, consistent with the onset of jet quenching. The spectral slope for
the "shoulder" region is independent of centrality and trigger p_T, which
offers constraints on energy transport mechanisms and suggests that the
"shoulder" region contains the medium response to energetic jets.Comment: 420 authors from 58 institutions, 6 pages, 4 figures. Submitted to
Physical Review Letters. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (or will be) publicly
available at http://www.phenix.bnl.gov/papers.htm
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