158 research outputs found
Evolución y distribución sectorial de las fusiones de empresas españolas
Es evidente que los procedimientos de fusión han sido empleados por las empresas españolas como estrategias para afrontar los retos competitivos en sus diferentes entornos económicos y, aunque han sido estudiados sus causas y resultados; el impacto global en el contexto de la economía española y su utilización real no han sido suficientemente investigados, sobre todo, debido a la falta de bases estadísticas apropiadas. En este trabajo, partiendo de la información de las últimas dos décadas, se analiza cuál ha sido su empleo efectivo, características y evolución, así como aquellos sectores más intensamente afectados. Para obtener una base que permita vislumbrar las posibles tendencias futuras de estas [email protected]
Band-pass filtering of the time sequences of spectral parameters for robust wireless speech recognition
In this paper we address the problem of automatic speech recognition when wireless speech communication systems are involved. In this context, three main sources of distortion should be considered: acoustic environment, speech coding and transmission errors. Whilst the first one has already received a lot of attention, the last two deserve further investigation in our opinion. We have found out that band-pass filtering of the recognition features improves ASR performance when distortions due to these particular communication systems are present. Furthermore, we have evaluated two alternative configurations at different bit error rates (BER) typical of these channels: band-pass filtering the LP-MFCC parameters or a modification of the RASTA-PLP using a sharper low-pass section perform consistently better than LP-MFCC and RASTA-PLP, respectively.Publicad
Short-term effect of zoledronic acid upon fracture resistance of the mandibular condyle and femoral head in an animal model
Objective: The aim of this study was to compare the effects in terms of resistance to fracture of the mandibular
condyle and femoral head following different doses of zoledronic acid in an animal model.
Study design: A total of 80 adult male Sprague-Dawley rats were included in a prospective randomized study.
The animals were randomly divided into four groups of 20 rats each. Group 1 (control) received sterile saline
solution, while groups 2, 3 and 4 received a accumulated dose of 0.2 mg, 0.4 mg and 0.6 mg of zoledronic acid,
respectively. The animals were sacrificed 28 days after the last dose, and the right hemimandible and the right
femur were removed. The fracture strength was measured (in Newtons) with a universal test machine using a 1
kN load connected to a metal rod with one end angled at 30 degrees. The cross-head speed was 1 mm/min. Later,
the specimens were observed under a scanning electron microscope with backscattered electron imaging (SEM-
BSE). At last, chemical analysis and elemental mapping of the mineral bone composition were generated using a
microanalytical system based on energy-dispersive and X-ray spectrometry (EDX).
Results: A total of 160 fracture tests were performed. The fracture resistance increased in mandible and femur
with a higher accumulated dose of zoledronic acid. Statistically significant differences were recorded versus
the controls with all the studies groups. The chemical analysis in mandible showed a significantly increased of
calcium and phosphorous to compare the control with all of the study groups; however, in femur no statistically
significant differences between the four study groups were observed.
Conclusions: The administration of bisphosphonates increases the fracture resistance in mandible and femur
Effect of posterior gingival smile on the perception of smile esthetics
Objectives: To evaluate and compare the influence of posterior gummy smile on the perception of smile esthetics
by orthodontists, general-dentists and laypersons.
Study Design: A frontal photograph of a smile with normal gum exposure was chosen and manipulated digitally
using Adobe Photoshop C3 to generate three further images with posterior gum exposure of 4, 6 and 8mm. These
four images were assessed by the three evaluator groups: orthodontists (n=40), general-dentists (n=40) and laypersons
(n=40). Both orthodontists and dentists had at least ten years professional experience and laypersons were
aged between 40-50 years. The proportion of men to women was 20:20 in each group.
Evaluators awarded a score to the smile esthetics of each image: 1=acceptable, 2=moderately acceptable,
3=unacceptable. Afterwards, each evaluator placed the four images in order of esthetic preference.
Results: No significant differences (p>0.05) were detected between the three evaluator groups for the photo without
posterior gummy smile. The perception of smile esthetics for a the 4mm posterior gummy smile (median for
orthodontists=2, general-dentists= 1, laypersons=1), the 6mm (median for orthodontists=2, general-dentists=1,
laypersons=1) and the 8mm (median for orthodontists=3, general-dentists=2, laypersons=2) was significantly different
between orthodontists and the other two evaluator groups (p<0.0017).
The three evaluator groups coincided in placing the image with the 6mm gum exposure in first place in order of
esthetic preference.
Conclusions: Posterior gummy smile influences the perception of smile esthetics more negatively among orthodontists
than the rest of the groups
Programa de educación para la salud dirigido a la prevención de cardiopatía isquémica en personas en edad adulto-anciana
La cardiopatía isquémica se define como la enfermedad cardíaca producida por las alteraciones fisiopatológicas secundarias a la aparición de un desequilibrio entre la demanda y el aporte de oxígeno del músculo cardíaco.Esta enfermedad es un problema de salud que produce 7,5 millones de muertes en el mundo y que puede ser controlado a partir de la modificación de estilos de vida y la disminución de factores de riesgo. Los principales factores de riesgo cardiovascular (modificables o no modificables) son la edad, el sexo, la hipertensión arterial, el tabaquismo, la diabetes mellitus, la dislipidemia y la obesidad.El papel de enfermería para el control de los factores de riesgo y seguimiento de una rutina saludable es imprescindible.ObjetivoDiseñar un programa de salud dirigido a reducir la tasa de morbimortalidad por cardiopatía isquémica mediante la prevención primaria en personas entre 50 y 70 años.MetodologíaPara la realización del trabajo se ha llevado a cabo una búsqueda bibliográfica entre los meses de febrero y mayo del año 2021 en diferentes bases de datos.DesarrolloSe va a realizar un programa de educación para la salud con 4 sesiones educativas en personas adulto-ancianas, para que tomen conciencia de la enfermedad y de la importancia de corregir factores de riesgo modificables.ConclusionesLos programas de educación para la salud destinados a la prevención cardiovascular realizan un papel imprescindible para evitar la enfermedad o su detección en fases tempranas. La prevención se aborda desde una perspectiva global, mediante la promoción de estilos de vida saludables y el control de los principales factores de riesgo.<br /
High-throughput DNA sequencing of microbiota at interproximal sites
©2020. This manuscript version is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by/4.0/
This document is the Published, version of a Published Work that appeared in final form in Journal of Oral Microbiology. To access the final edited and published work seehttps://doi.org/10.1080/20002297.2019.1687397Objective: The oral microbiota has been deeply studied by high-throughput sequencing
techniques. However, although the interproximal regions have one of the highest caries rates
in the oral cavity, information about the bacterial composition at those sites is scarce.
Methods: In this study, we used 16S rRNA Illumina sequencing to describe the microbiota
associated to interproximal regions at two time points. In addition, dental plaque samples at
the vestibular and lingual surfaces from the same teeth were also analysed at the two time
points.
Results: Interproximal-associated microbiota was found to be similar to already described
bacterial communities in other mouth niches. Streptoccocus, Veillonella, Rothia, Actinomyces,
Neisseria, Haemophilus and Fusobacterium were the most abundant genera in this oral region.
Statistical analyses showed that the microbiota from interproximal sites was more similar to
that sampled from the vestibular surfaces than to the lingual surfaces. Interestingly, many
potentially cariogenic bacteria such as Scardovia, Atopobium or Selenomonas were overrepresented
in the interproximal regions in comparison with vestibular and lingual sites.
Conclusion: The microbiota at interproximal regions appears to be specific and stable
through time. Potentially pathogenic bacteria may increase caries development risk and
gingival inflammation at those sites
Conceptos actuales de la fisiopatología de las tendinopatías. Ingeniería tisular
La tendinopatía es una lesión frecuente que se produce durante la práctica deportiva.
El reparto desigual de la carga de trabajo a lo largo del tendón produce roturas heterogéneas en extensión y distribución. Estas roturas ponen en marcha procesos de reparación defectuosos que producen un tendón degenerado con alteración estructural y de la respuesta funcional al ejercicio.
En este trabajo se estudian y analizan los distintos factores predisponentes, mecanismos de acción de los agentes químicos y celulares implicados en la fisiopatología de la tendinopatías.
Por otra parte, se analizan los componentes básicos (soporte, células y sustancias químicas) que se usan para la ingeniería tisular. Las posibilidades actuales de uso de los componentes básicos y sus interrelaciones, y el nivel actual de desarrollo
Conceptes actuals de la fisiopatologia de les tendinopaties. Enginyeria tissular
La tendinopatia és una lesió freqüent que es produeix durant la pràctica esportiva. El repartiment desigual de la càrrega de treball al llarg del tendó produeix trencaments heterogenis en extensió i distribució. Aquests trencaments posen en marxa processos de reparació defectuosos que produeixen un tendó degenerat amb alteració estructural i de la resposta funcional a l’exercici.
En aquest treball s’estudien i analitzen els diferents factors predisponents, mecanismes d’acció dels agents químics i cel·lulars implicats en la fisiopatologia de les tendinopaties.
D’altra banda, s’analitzen els components bàsics (suport, cèl·lules i substàncies químiques) que es fan servir per a la ingenieria tissular. Les probabilitats actuals d’ús dels components bàsics i les seves interrelacions i el nivell actual de desenvolupament
Effect of water contamination on the shear bond strength of five orthodontic adhesives
Objectives: To evaluate the shear bond strength and site of failure of brackets bonded to dry and wet enamel. Study design: 50 teeth were divided into ten groups of 5 teeth each (10 surfaces). In half the groups enamel was kept dry before bonding, and in the other half distilled water was applied to wet the surface after etching. The following groups were established: 1)Acid/Transbond-XT (dry/wet) XT; 2) Transbond Plus Self Etching Primer (TSEP)/Transbond-XT paste (dry/wet); 3) Concise (dry), Transbond MIP/Concise (wet), 4) FujiOrtho-LC (dry/wet); 5) SmartBond (dry/wet). Brackets were bonded to both buccal and lingual surfaces. Specimens were stored in distilled water (24 hours at 37ºC) and thermocycled. Brackets were debonded using a Universal testing machine (cross-head speed 1 mm/min). Failure sites were classified using a stereomicroscope. Results: No significant differences in bond strength were detected between the adhesives under wet and dry conditions except for Smart- Bond, whose bond strength was significantly lower under dry conditions. For all the adhesives most bond failures were of mixed site location except for Smartbond, which failed at the adhesive-bracket interface. Conclusions: Under wet conditions the bonding capacity of the adhesives tested was similar than under dry conditions, with the exception of SmartBond which improved under wet condition
Effect of antibiotics and NSAIDs on ciclooxygenase-2 in the enamel mineralization
©2018. This manuscript version is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by /4.0/
This document is the Published, version of a Published Work that appeared in final form in Scientific Reports. To access the final edited and published work see https://doi.org/10.1038/s41598-018-22607-zThe objective of this study was to determine whether the use of the most commonly prescribed antibiotics
and non-steroidal anti-inflammatory drugs in childhood could disturb enamel mineralization. Forty-two
Swiss mice were divided into seven groups: controls; amoxicillin; amoxicillin/clavulanate; erythromycin;
acetaminophen; ibuprofen and celecoxib, to inhibit cyclooxygenase 2 (COX2). SEM-EDX analysis
was conducted on all cusps of the third molars. Calcium (Ca), phosphorus (P), aluminum, potassium,
sodium, magnesium and chlorine were quantified. The stoichiometric Ca/P molar ratios were calculated.
Immunohistochemical quantification of COX2 in incisors was carried out by image analysis using COX2-
specific immunostaining. Groups treated with antibiotics showed no significant differences in the content
of the chemical elements. Only acetaminophen and celecoxib showed a significant decrease in Ca and P
compared with the control samples. Ca/P ratios showed no difference. Groups treated with amoxicillin,
amoxicillin/clavulanate, erythromycin and acetaminophen showed significantly lower amounts of
immunoreactive COX2 at the enamel organ maturation stage of the mouse incisors. Our results suggest
that COX2 is involved in the maturation stage of the enamel organ and that its inhibition would appear to
alter amelogenesis, producing hypomineralization
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