491 research outputs found
Hepatocyte growth factor modulates in vitro survival and proliferation of germ cells during postnatal testis development
The hepatocyte growth factor (HGF) is a pleiotropic cytokine that influences mitogenesis, motility and differentiation of many different cell types by its tyrosine kinase receptor c-Met. We previously demonstrated that the c-Met/HGF systern is present and functionally active during postnatal testis development. We found also that spermatozoa express c-Met and that HGF has a positive effect on the maintenance of sperm motility. In the present paper, we extend our study on the germ cells at different stages of differentiation during the postnatal development of the testis. We demonstrate that c-met is present in rat spermatogonia, pachytene spermatocytes and round spermatids and that HGF significantly increases spermatogonial proliferation in 8- to 10-day-old prepubertal rats. At this age HGF does not affect Sertoli cells and peritubular myoid cells proliferation. In addition, we studied the effect of the factor on germ cell apoptosis and we show that HGF prevents the genii cell apoptotic process. We also studied the effect of HGF on 18- to 20-day-old and 28- to 30-day-old rat testes. At these ages also the factor significantly increases genii cell duplication and decreases the number of apoptotic cells. However, the effect on programmed cell death is higher in the 8- to 10-day-old rats and declines in the older animals. In conclusion, we report that rat genii cells (spermatogonia, pachytene spermatocytes and round spermatids) express c-met and that HGF modulates genii cell proliferating activity and apoptosis in vitro. These data indicate that the c-Met/HGF system is involved in male germ cell homeostasis and, consequently, has a role in mate fertility
Comprensión lectora en el pensamiento crítico en estudiantes de sexto grado de primaria de una institución educativa, Los Olivos, 2023
El estudio tuvo como objetivo general concluir la influencia entre la comprensión
lectora en el pensamiento crítico en estudiantes de sexto grado de primaria de
una Institución Educativa, Los Olivos, 2023. La investigación fue de enfoque
cuantitativo, tipo de investigación básica, diseño no experimental, transversal
descriptivo de nivel correlacional – causal con regresión lineal. Se trabajó con 80
estudiantes, entre niños y niñas de sexto grado de primaria, mediante muestreo
no probabilístico. Se aplicó instrumentos validados por expertos y evaluados en
confiabilidad mediante el KR20 y el Alfa de Cronbach, los coeficientes fueron de
0,753 y 0,937, para la comprensión de lectora y el pensamiento crítico
respectivamente. Los resultados muestran una correlación nula (R=0,039) en el
rango y fortalezas de correlaciones de Pearson, A su vez, el valor de la
correlación asintótica bilateral es de 0,729 superando de manera significativa a
0,05 lo que implica la aceptación de la hipótesis nula y se rechaza la hipótesis
de investigación. En conclusión, no existe influencia entre la compresión lectora
en el pensamiento crítico de los estudiantes
Actitudes hacia la conciencia ambiental estudiantil en Los Olivos, 2022
La investigación tuvo como objetivo determinar el nivel de actitudes hacia la
conciencia ambiental estudiantil. La metodología que se empleó fue la investigación
básica, con enfoque cuantitativo y diseño no experimental, la muestra fue de 100
estudiantes originarios de los Olivos. La técnica utilizada para recolectar datos fue la
encuesta y el instrumento que se utilizó fue un cuestionario con el que se reportó el
nivel de actitudes hacia la conciencia ambiental. Los resultados mostraron que la
variable se encuentra en proceso (85%), la dimensión afectiva (60%) y cognitiva
(58%) están en el logro estimado, conativa (45%) y activa (48%) presentado utilidades
en proceso. Las actitudes hacia la conciencia ambiental se construyen con las
vivencias del día a día, dándole la oportunidad al estudiante de crear su propio
significado y valor. Se concluye en que las actitudes ambientales se encuentran en
nivel de proceso
Galaxy quenching timescales from a forensic reconstruction of their colour evolution
The timescales on which galaxies move out of the blue cloud to the red
sequence () provide insight into the mechanisms driving
quenching. Here, we build upon previous work, where we showcased a method to
reconstruct the colour evolution of observed low-redshift galaxies from the
Galaxy And Mass Assembly (GAMA) survey based on spectral energy distribution
(SED) fitting with ProSpect, together with a statistically-driven definition
for the blue and red populations. We also use the predicted colour evolution
from the SHARK semi-analytic model, combined with SED fits of our simulated
galaxy sample, to study the accuracy of the measured and
gain physical insight into the colour evolution of galaxies. In this work, we
measure in a consistent approach for both observations and
simulations. After accounting for selection bias, we find evidence for an
increase in in GAMA as a function of cosmic time (from
Gyr to Gyr in the lapse of
Gyr), but not in SHARK ( Gyr). Our
observations and simulations disagree on the effect of stellar mass, with GAMA
showing massive galaxies transitioning faster, but is the opposite in SHARK. We
find that environment only impacts galaxies below M in
GAMA, with satellites having shorter than centrals by
Gyr, with SHARK only in qualitative agreement. Finally, we compare to
previous literature, finding consistency with timescales in the order of couple
Gyr, but with several differences that we discuss.Comment: 17 pages, 14 figures. Submitted to MNRAS. Updated to reflect changes
addressing the referee's comment
Deep Extragalactic VIsible Legacy Survey (DEVILS): SED fitting in the D10-COSMOS field and the evolution of the stellar mass function and SFR–M⋆ relation
We present catalogues of stellar masses, star formation rates (SFRs), and ancillary stellar population parameters for galaxies spanning 0 \u3c z \u3c 9 from the Deep Extragalactic VIsible Legacy Survey (DEVILS). DEVILS is a deep spectroscopic redshift survey with very high completeness, covering several premier deep fields including COSMOS (D10). Our stellar mass and SFR estimates are self-consistently derived using the spectral energy distribution (SED) modelling code PROSPECT, using well-motivated parametrizations for dust attenuation, star formation histories, and metallicity evolution. We show how these improvements, and especially our physically motivated assumptions about metallicity evolution, have an appreciable systematic effect on the inferred stellar masses, at the level of ∼0.2 dex. To illustrate the scientific value of these data, we map the evolving galaxy stellar mass function (SMF) and the SFR–M⋆ relation for 0 \u3c z \u3c 4.25. In agreement with past studies, we find that most of the evolution in the SMF is driven by the characteristic density parameter, with little evolution in the characteristic mass and low-mass slopes. Where the SFR–M⋆ relation is indistinguishable from a power law at z \u3e 2.6, we see evidence of a bend in the relation at low redshifts (z \u3c 0.45). This suggests evolution in both the normalization and shape of the SFR–M⋆ relation since cosmic noon. It is significant that we only clearly see this bend when combining our new DEVILS measurements with consistently derived values for lower redshift galaxies from the Galaxy And Mass Assembly (GAMA) survey: this shows the power of having consistent treatment for galaxies at all redshifts
Deep Extragalactic VIsible Legacy Survey (DEVILS): SED Fitting in the D10-COSMOS Field and the Evolution of the Stellar Mass Function and SFR- relation
We present catalogues of stellar masses, star formation rates, and ancillary
stellar population parameters for galaxies spanning from the Deep
Extragalactic VIsible Legacy Survey (DEVILS). DEVILS is a deep spectroscopic
redshift survey with very high completeness, covering several premier deep
fields including COSMOS (D10). Our stellar mass and star formation rate
estimates are self-consistently derived using the spectral energy distribution
(SED) modeling code ProSpect, using well-motivated parameterisations for dust
attenuation, star formation histories, and metallicity evolution. We show how
these improvements, and especially our physically motivated assumptions about
metallicity evolution, have an appreciable systematic effect on the inferred
stellar masses, at the level of 0.2 dex. To illustrate the scientific
value of these data, we map the evolving galaxy stellar mass function (SMF) for
and the SFR- relation for . In agreement with past
studies, we find that most of the evolution in the SMF is driven by the
characteristic density parameter, with little evolution in the characteristic
mass and low-mass slopes. Where the SFR- relation is indistinguishable
from a power-law at , we see evidence of a bend in the relation at low
redshifts (). This suggests evolution in both the normalisation and
shape of the SFR- relation since cosmic noon. It is significant that
we only clearly see this bend when combining our new DEVILS measurements with
consistently derived values for lower redshift galaxies from the Galaxy And
Mass Assembly (GAMA) survey: this shows the power of having consistent
treatment for galaxies at all redshifts.Comment: Submitted for publication in MNRA
Development of a mouse model for spontaneous oral squamous cell carcinoma in Fanconi anemia
Altres ajuts: European Regional Development Fund (FEDER); the European Union; the Spanish Fundacion Anemia de Fanconi and Fanconi Anemia Research Fund USA; Comunidad de Madrid (ref PEJ-2019-TL_BMD-12905).Fanconi anemia (FA) patients frequently develop oral squamous cell carcinoma (OSCC). This cancer in FA patients is diagnosed within the first 3-4 decades of life, very often preceded by lesions that suffer a malignant transformation. In addition, they respond poorly to current treatments due to toxicity or multiple recurrences. Translational research on new chemopreventive agents and therapeutic strategies has been unsuccessful partly due to scarcity of disease models or failure to fully reproduce the disease. Here we report that Fanca gene knockout mice (Fanca ) frequently display pre-malignant lesions in the oral cavity. Moreover, when these animals were crossed with animals having conditional deletion of Trp53 gene in oral mucosa (K14cre;Trp53), they spontaneously developed OSCC with high penetrance and a median latency of less than ten months. Tumors were well differentiated and expressed markers of squamous differentiation, such as keratins K5 and K10. In conclusion, Fanca and Trp53 genes cooperate to suppress oral cancer in mice, and Fanca;K14cre;Trp53 mice constitute the first animal model of spontaneous OSCC in FA
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
5to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica
El V Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2019, realizado del 6 al 8 de febrero de 2019 y organizado por la Universidad Politécnica Salesiana, ofreció a la comunidad académica nacional e internacional una plataforma de comunicación unificada, dirigida a cubrir los problemas teóricos y prácticos de mayor impacto en la sociedad moderna desde la ingeniería.
En esta edición, dedicada a los 25 años de vida de la UPS, los ejes temáticos estuvieron relacionados con la aplicación de la ciencia, el desarrollo tecnológico y la innovación en cinco pilares fundamentales de nuestra sociedad: la industria, la movilidad, la sostenibilidad ambiental, la información y las telecomunicaciones.
El comité científico estuvo conformado formado por 48 investigadores procedentes de diez países: España, Reino Unido, Italia, Bélgica, México, Venezuela, Colombia, Brasil, Estados Unidos y Ecuador.
Fueron recibidas un centenar de contribuciones, de las cuales 39 fueron aprobadas en forma de ponencias y 15 en formato poster. Estas contribuciones fueron presentadas de forma oral ante toda la comunidad académica que se dio cita en el Congreso, quienes desde el aula magna, el auditorio y la sala de usos múltiples de la Universidad Politécnica Salesiana, cumplieron respetuosamente la responsabilidad de representar a toda la sociedad en la revisión, aceptación y validación del conocimiento nuevo que fue presentado en cada exposición por los investigadores.
Paralelo a las sesiones técnicas, el Congreso contó con espacios de presentación de posters científicos y cinco workshops en temáticas de vanguardia que cautivaron la atención de nuestros docentes y estudiantes. También en el marco del evento se impartieron un total de ocho conferencias magistrales en temas tan actuales como la gestión del conocimiento en la universidad-ecosistema, los retos y oportunidades de la industria 4.0, los avances de la investigación básica y aplicada en mecatrónica para el estudio de robots de nueva generación, la optimización en ingeniería con técnicas multi-objetivo, el desarrollo de las redes avanzadas en Latinoamérica y los mundos, la contaminación del aire debido al tránsito vehicular, el radón y los riesgos que representa este gas radiactivo para la salud humana, entre otros
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