140 research outputs found
A first step to accelerating fingerprint matching based on deformable minutiae clustering
Fingerprint recognition is one of the most used biometric
methods for authentication. The identification of a query fingerprint requires
matching its minutiae against every minutiae of all the fingerprints
of the database. The state-of-the-art matching algorithms are costly, from
a computational point of view, and inefficient on large datasets. In this
work, we include faster methods to accelerating DMC (the most accurate
fingerprint matching algorithm based only on minutiae). In particular,
we translate into C++ the functions of the algorithm which represent the
most costly tasks of the code; we create a library with the new code and
we link the library to the original C# code using a CLR Class Library
project by means of a C++/CLI Wrapper. Our solution re-implements
critical functions, e.g., the bit population count including a fast C++
PopCount library and the use of the squared Euclidean distance for calculating
the minutiae neighborhood. The experimental results show a
significant reduction of the execution time in the optimized functions of
the matching algorithm. Finally, a novel approach to improve the matching
algorithm, considering cache memory blocking and parallel data processing,
is presented as future work.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Spin polarization induced by decoherence in a tunneling one-dimensional Rashba model
Basic questions on the nature of spin polarization in two terminal systems
and the way in which decoherence breaks Time-Reversal Symmetry (TRS) are
analyzed. We exactly solve several one-dimensional models of tunneling
electrons and show the interplay of spin precession and decay of the
wavefunction in either a U(1) magnetic field or an effective Spin-Orbit (SO)
magnetic field. Spin polarization is clearly identified as the emergence of a
spin component parallel to either magnetic field. We show that Onsager's
reciprocity is fulfilled when time reversal symmetry is present and no spin
polarization arises, no matter the barrier parameters or the SO strength.
Introducing a Buttiker's decoherence probe, that preserves unitarity of time
evolution, we show that breaking of TRS results in a strong spin polarization
for realistic SO, and barrier strengths. We discuss the significance of these
results as a very general scenario for the onset of the Chiral-Induced Spin
Selectivity effect (CISS), now possibly matching experiments in a quantitative
manner.Comment: 24 pages, 14 figure
Nonadiabatic charged spherical evolution in the postquasistatic approximation
We apply the postquasistatic approximation, an iterative method for the
evolution of self-gravitating spheres of matter, to study the evolution of
dissipative and electrically charged distributions in General Relativity. We
evolve nonadiabatic distributions assuming an equation of state that accounts
for the anisotropy induced by the electric charge. Dissipation is described by
streaming out or diffusion approximations. We match the interior solution, in
noncomoving coordinates, with the Vaidya-Reissner-Nordstr\"om exterior
solution. Two models are considered: i) a Schwarzschild-like shell in the
diffusion limit; ii) a Schwarzschild-like interior in the free streaming limit.
These toy models tell us something about the nature of the dissipative and
electrically charged collapse. Diffusion stabilizes the gravitational collapse
producing a spherical shell whose contraction is halted in a short
characteristic hydrodynamic time. The streaming out radiation provides a more
efficient mechanism for emission of energy, redistributing the electric charge
on the whole sphere, while the distribution collapses indefinitely with a
longer hydrodynamic time scale.Comment: 11 pages, 16 Figures. Accepted for publication in Phys Rev
FIRST REPORT OF USE OF LAND SNAILS FOR HETEROMYS GAUMERI (RODENTIA: HETEROMYIDAE) IN A SUBDECIDUOUS FOREST IN YUCATÁN, MÉXICO
Se presenta el primer registro de uso de caracoles terrestres por Heteromys gaumeri en la selva mediana subcaducifolia localizada en el Rancho Hobonil, Tzucacab, Yucatán, México. Siete por ciento de la población total (n= 789) de H. gaumeri usó caracoles que habitan en el área. Las especies fueron: Choanopoma largillierti y C. gaigei (Annulariidae), Neocyclotus dysoni (Cyclophoridae) y Drymaeus shattucki (Bulimulidae). Cincuenta y uno por ciento de las muestras de los roedores fueron hembras y el 49% machos. Los adultos representaron el 86% y los juveniles 14%. El uso de caracoles tuvo relación significativa entre sexos de los roedores y la estacionalidad (p< 0.01). Los caracoles fueron usados con mayor frecuencia en la estación de sequía por las hembras y por los machos adultos y juveniles en la de lluvias. Treinta y cinco por ciento de las hembras de la muestra que usaron caracoles estaban preñadas o lactantes. El género Choanopoma fue el más abundante y removido por H. gaumeri en ambas estaciones, mientras que Neocyclotus lo fue en la de lluvias y D. shattucki se encontró rara vez. Por lo observado consideramos que este ratón además de semillas come caracoles terrestres en esta región
Validation of models with constant bias: an applied approach
Objective. This paper presents extensions to the statistical validation method based on the procedure of Freese when a model shows constant bias (CB) in its predictions and illustrate the method with data from a new mechanistic model that predict weight gain in cattle. Materials and methods. The extensions were the hypothesis tests and maximum anticipated error for the alternative approach, and the confidence interval for a quantile of the distribution of errors. Results. The model evaluated showed CB, once the CB is removed and with a confidence level of 95%, the magnitude of the error does not exceed 0.575 kg. Therefore, the validated model can be used to predict the daily weight gain of cattle, although it will require an adjustment in its structure based on the presence of CB to increase the accuracy of its forecasts. Conclusions. The confidence interval for the 1-α quantile of the distribution of errors after correcting the constant bias, allows determining the top limit for the magnitude of the error of prediction and use it to evaluate the evolution of the model in the forecasting of the system. The confidence interval approach to validate a model is more informative than the hypothesis tests for the same purpose
Anemia y su asociación con el peso del recién nacido en gestantes adolescentes: ¿mito o realidad?
Objective. To determine the relationship between maternal hemoglobin of pregnant adolescents and the weight of newborns in the National Maternal Perinatal Institute (INMP). Material and methods. 914 pregnant women were analyzed cross-sectionally by inclusion and exclusion criteria of 2729 deliveries of adolescents attended in the INMP corresponding to the year 2017. The data were collected from the birth registry and clinical histories, the variables of interest were hemoglobin maternal and the weight of the newborn. Results. Of the 914 births, 299 mothers (32%) presented anemia and 615 (68%) did not present anemia, the predominant age group were adolescents in the late stage 73% (with anemia) and 71% (without anemia). In the prenatal control, there was a predominance of insufficient or uncontrolled 74% (with anemia) and 73% (without anemia). Single women were the majority group, 91% (with anemia) and 93% (without anemia). The origin of the districts with quintiles IV and V was 90% (with anemia) and 87% (without anemia). No association was found between the weight of the newborn and the hemoglobin of the third trimester of the mother (Pearson's r = -0.0141, p-value = 0.6702). Conclusions. We did not find a relationship between low maternal hemoglobin and birth weight at term pregnancies of adolescents, this could be due to the fact that in the control of fetal weight there would be multiple factors that could be more influential in this group of pregnant adolescents.Objetivo. Determinar la relación existente entre la hemoglobina materna de gestantes adolescentes y el peso de los recién nacidos en el Instituto Nacional Materno Perinatal (INMP). Material y métodos. Transversalmente se analizaron 914 gestantes seleccionadas mediante criterios de inclusión y exclusión de 2729 partos de adolescentes atendidas en el INMP correspondiente al año 2017. Los datos se recogieron del registro de partos y las historias clínicas, las variables de interés fueron la hemoglobina materna y el peso del recién nacido. Resultados. De los 914 partos 299 madres (32%) presentaron anemia y 615 (68%) no la presentaron, el grupo etario predominante fueron las adolescentes en la etapa tardía 73% (con anemia) y 71% (sin anemia). En el control prenatal predominó los insuficiente o sin control 74% (con anemia) y 73%(sin anemia). Las solteras fueron el grupo mayoritario, 91% (con anemia) y 93% (sin anemia). La procedencia de los distritos con quintiles IV y V fue el 90% (con anemia) y el 87% (sin anemia). No se encontró asociación entre el peso del recién nacido y la hemoglobina del tercer trimestre de la madre (r de Pearson = -0,0141; valor p = 0,6702). Conclusiones. No encontramos relación entre la hemoglobina materna baja y el peso al nacimiento de gestaciones a término de adolescentes, esto podría deberse a que en el control del peso fetal existirían múltiples factores que podrían ser más influyentes en este grupo de gestantes adolescentes
Proposal of a water-quality index for high andean basins: application to the Chumbao river, Andahuaylas, Peru
Thewater fromthe high Andean rivers is peculiar due to its composition and the geomorphology
of its sources, and naturally or anthropogenically contamination is not discarded along its course.
This water is used for agriculture and human consumption, therefore knowing its quality is important.
This research aimed to proposing and formulate a water-quality index for high Andean basins through
the Delphimethod, and its application in the Chumbao River located in Andahuaylas-Peru. Forty-three
water-quality parameters were evaluated through the Delphi method, and the water-quality index
(WQIHA) was formulated with a weighted average of the weights of the selected parameters, it was
compared with the WQI Dinius. For this purpose, ten sampling points were considered along the
Chumbao River located between 4274 and 2572 m of altitude and theWQIHA was applied. In addition,
field and laboratory analyses were carried out in 2018, 2019, and 2021, in dry and rainy seasons. Twenty
parameters were grouped in the physicochemical sub-index (SIPC), heavy metals sub-index (SIHM),
and organic matter sub-index (SIOM). Each group contributed with weights of 0.30, 0.30, and 0.40,
respectively, for theWQIHA formulation. The SIPC and SIOM showed that the areas near the head of
the basin presented excellent and good quality, while the urbanized areas were qualified as marginal
to poor; SIHM reported good quality in all points and seasons. Regarding the WQIHA, the index
shows good quality in the zones above 3184 m of altitude, contrasting with poor quality downstream,
decreasing notably in both seasons, suggesting continuous degradation of the water body
Serious liver injury induced by Nimesulide: an international collaboration study reporting 57 cases
Nimesulide is a non-steroidal anti-inflammatory drug still marketed in many countries. We aim to analyze the clinical phenotype, outcome, and histological features of nimesulide-induced liver injury (nimesulide-DILI). We analyzed 57 cases recruited from the Spanish and LATIN DILI registries. Causality was assessed by the RUCAM scale. Mean age of the whole case series was 59 years (86% women) with a median time to onset of 40 days. A total of 46 patients (81%) were jaundiced. Nimesulide-DILI pattern was hepatocellular in 38 (67%), mixed in 12 (21%), and cholestatic in 7 (12%) cases. Transaminases were elevated with a mean of nearly 20-fold the upper limit of normality (ULN), while alkaline phosphatase showed a 2-fold mean elevation above ULN. Total bilirubin showed a mean elevation of 13-fold the ULN. Liver histology was obtained in 14 cases (25%), most of them with a hepatocellular pattern. Median time to recovery was 60 days. Overall, 12 patients (21%) developed acute liver failure (ALF), five (8.8%) died, three underwent liver transplantation (5.3%), and the remaining four resolved. Latency was ≤15 days in 12 patients (21%) and one patient developed ALF within seven days from treatment initiation. Increased total bilirubin and aspartate transaminase levels were independently associated with the development of ALF. In summary, nimesulide-DILI affects mainly women and presents typically with a hepatocellular pattern. It is associated with ALF and death in a high proportion of patients. Shorter (≤15 days) duration of therapy does not prevent serious nimesulide hepatotoxicity, making its risk/benefit ratio clearly unfavorable.The present study has been supported by grants of Instituto de Salud Carlos III cofounded by Fondo Europeo de Desarrollo Regional - FEDER (contract numbers: PI18-00901; PI 18/01804; PT20/00127) and Agencia Española del Medicamento. Plataforma ISCiii de Investigación Clínica and CIBERehd are funded by ISCIII. MRD holds a Joan Rodes (JR16/00015)/Acción B clinicos investigadores (B-0002-2019) research contract from ISCIII and Consejería de Salud de Andalucía, IAA holds a Sara Borrell research contract from the National Health System, ISCIII (CD 20/00083)
Mirror-Mark Tests Performed on Jackdaws Reveal Potential Methodological Problems in the Use of Stickers in Avian Mark-Test Studies
Some animals are capable of recognizing themselves in a mirror, which is considered to be demonstrated by passing the mark test. Mirror self-recognition capacity has been found in just a few mammals having very large brains and only in one bird, the magpie (Pica pica). The results obtained in magpies have enormous biological and cognitive implications because the fact that magpies were able to pass the mark test meant that this species is at the same cognitive level with great apes, that mirror self-recognition has evolved independently in the magpie and great apes (which diverged 300 million years ago), and that the neocortex (which is not present in the bird's brains) is not a prerequisite for mirror self-recognition as previously believed. Here, we have replicated the experimental design used on magpies to determine whether jackdaws (Corvus monedula) are also capable of mirror self-recognition by passing the mark test. We found that our nine jackdaws showed a very high interest towards the mirror and exhibited self-contingent behavior as soon as mirrors were introduced. However, jackdaws were not able to pass the mark test: both sticker-directed actions and sticker removal were performed with a similar frequency in both the cardboard (control) and the mirror conditions. We conclude that our jackdaws' behaviour raises non-trivial questions about the methodology used in the avian mark test. Our study suggests that the use of self-adhesive stickers on sensitive throat feathers may open the way to artefactual results because birds might perceive the stickers tactilely.JMPS was funded by Ministerio de Educación and Consejería de Innovación, C 420 iencia y Empresa under International Excellence Campus Program (CEI Granada) and TPC was funded by Ministerio de Educación y Ciencia by a postdoctoral contract from the project CGL2011-25634
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