85 research outputs found
Embalse subterráneo, Brasil.
Se tiene conocimiento de la técnica de almacenamiento de agua através del uso de embalses subterráneos en varias partes del mundo; en Arizona, Estados Unidos; en el desierto de Negev, en Israel; en las rcgiones áridas de Africa del Norte y en el desierto del Sahara. en Irán
Embalse para riego de salvación, Brasil.
EI aprovechamiento deI agua que escurre en Ia superficie deI suelo es una técnica de captación de agua de lluvia que data de 4 000 anos atrás, siendo utilizada por los agricultores de Ia edad de bronce en e\ desierto de Negev en Israel. En ese entonces, recogían Ias piedras encontradas en Ia superficie dei suelo para aumentar Ia cantidad de agua a escurrir; también, construían tanques de almacenamiento y diques divisorios con Ia finalidad de captar y conducir agua hacia Ias partes bajas de los campos para regar sus cultivos.bitstream/item/109825/1/Artigo-Everaldo.pd
Lack of robustness of textural measures obtained from 3D brain tumor MRIs impose a need for standardization
Purpose Textural measures have been widely explored as imaging biomarkers in cancer. However, their robustness under dynamic range and spatial resolution changes in brain 3D magnetic resonance images (MRI) has not been assessed. The aim of this work was to study potential variations of textural measures due to changes in MRI protocols. Materials and methods Twenty patients harboring glioblastoma with pretreatment 3D T1-weighted MRIs were included in the study. Four different spatial resolution combinations and three dynamic ranges were studied for each patient. Sixteen three-dimensional textural heterogeneity measures were computed for each patient and configuration including co-occurrence matrices (CM) features and run-length matrices (RLM) features. The coefficient of variation was used to assess the robustness of the measures in two series of experiments corresponding to (i) changing the dynamic range and (ii) changing the matrix size. Results No textural measures were robust under dynamic range changes. Entropy was the only textural feature robust under spatial resolution changes (coefficient of variation under 10% in all cases). Conclusion Textural measures of three-dimensional brain tumor images are not robust neither under dynamic range nor under matrix size changes. Standards should be harmonized to use textural features as imaging biomarkers in radiomic-based studies. The implications of this work go beyond the specific tumor type studied here and pose the need for standardization in textural feature calculation of oncological images
Carbapenem-resistant Citrobacter spp. isolated in Spain from 2013 to 2015 produced a variety of carbapenemases including VIM-1, OXA-48, KPC-2, NDM-1 and VIM-2
Objectives: There is little information about carbapenemase-producing (CP) Citrobacter spp.We studied the molecular epidemiology and microbiological features of CP Citrobacter spp. isolates collected in Spain (2013-15).
Methods: In total, 119 isolates suspected of being CP by the EUCAST screening cut-off values were analysed. Carbapenemases and ESBLs were characterized using PCR and sequencing. The genetic relationship among Citrobacter freundii isolates was studied by PFGE.
Results: Of the 119 isolates, 63 (52.9%) produced carbapenemases, of which 37 (58.7%) produced VIM-1, 20 (31.7%) produced OXA-48, 12 (19%) produced KPC-2, 2 (3.2%) produced NDM-1 and 1 (1.6%) produced VIM- 2; 9 C. freundii isolates co-produced VIM-1 plus OXA-48. Fourteen isolates (22.2%) also carried ESBLs: 8 CTX-M-9 plus SHV-12, 2 CTX-M-9, 2 SHV-12 and 2 CTX-M-15. Fifty-seven isolates (90.5%) were C. freundii, 4 (6.3%) were Citrobacter koseri, 1 (1.6%) was Citrobacter amalonaticus and 1 (1.6%) was Citrobacter braakii. By EUCAST breakpoints, eight (12.7%) of the CP isolates were susceptible to the four carbapenems tested. In the 53 CP C. freundii analysed by PFGE, a total of 44 different band patterns were observed. Four PFGE clusters were identified: cluster 1 included eight isolates co-producing VIM-1 and OXA-48; blaVIM-1 was carried in a class 1 integron (intI-blaVIM-1 - aacA4-dfrB1-aadA1-catB2-qacE¿1/sul1) and blaOXA-48 was carried in a Tn1999.2 transposon.
Conclusions: We observed the clonal and polyclonal spread of CP Citrobacter spp. across several Spanish geographical areas. Four species of Citrobacter spp. produced up to five carbapenemase types, including coproduction of VIM-1 plus OXA-48. Some CP Citrobacter spp. isolates were susceptible to the four carbapenems tested, a finding with potential clinical implications
Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in Listeria monocytogenes
Background: In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings: By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance: Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat
Exercise Increases Serum Fibroblast Growth Factor 21 (FGF21) Levels
Fibroblast growth factor 21 (FGF21) increases glucose uptake. It is unknown if FGF21 serum levels are affected by exercise.This was a comparative longitudinal study. Anthropometric and biochemical evaluation were carried out before and after a bout of exercise and repeated after two weeks of daily supervised exercise. The study sample was composed of 60 sedentary young healthy women. The mean age was 24±3.7 years old, and the mean BMI was 21.4±7.0 kg/m². The anthropometric characteristics did not change after two weeks of exercise. FGF21 levels significantly increased after two weeks of exercise (276.8 ng/l (142.8-568.6) vs. (460.8 (298.2-742.1), p<0.0001)). The delta (final-basal) log of serum FGF21, adjusted for BMI, showed a significant positive correlation with basal glucose (r = 0.23, p = 0.04), mean maximal heart rate (MHR) (r = 0.54, p<0.0001), mean METs (r = 0.40, p = 0.002), delta plasma epinephrine (r = 0.53, p<0.0001) and delta plasma FFAs (r = 0.35, p = 0.006). A stepwise linear regression model showed that glucose, MHR, METs, FFAs, and epinephrine, were factors independently associated with the increment in FGF21 after the exercise program (F = 4.32; r² = 0.64, p<0.0001).Serum FGF21 levels significantly increased after two weeks of physical activity. This increment correlated positively with clinical parameters related to the adrenergic and lipolytic response to exercise.ClinicalTrials.gov NCT01512368
Respuestas de oyentes y expertos musicales a una encuesta para valorar la percepción musical en salas de conciertos, auditorios y teatros
Para valorar la percepción musical en salas de concierto se diseñó una encuesta de 58 preguntas
en la que cada una se valoraba de 0 a 5 puntos. A esta encuesta han respondido 1057 personas
entre público en general y expertos musicales, sin formación especializada en acústica, tras la
audición de un concierto en alguno de los 14 auditorios, salas de conciertos y teatros ubicados en
diferentes comunidades de nuestro país (8 en el sur y 6 en levante). El análisis de las respuestas
obtenidas ha mostrado que la fluctuación de la valoración media de cada una de las preguntas de
la encuesta en una sala es un patrón que se repite aproximadamente en todas las salas
estudiadas, formando una banda de aproximadamente 1 punto de variación en cada respuesta que
contiene a todas las salas. Los límites de esta banda indicarían los extremos de respuesta
subjetiva asociada a las salas de conciertos.Ponencia presentada en el Encuentro Ibérico de Acústica. EAA Symposium. Gandía(España). 2006.In order to evaluate the quality of the musical perception in concert halls, a survey with 58 items
was designed in which each question was valued from 0 to 5 points. This survey has been replied
by 1057 people between general public and musical experts without any specialized formation in
acoustics, after the audition of a concert in any of the 14 auditoriums, concert hall or theatres,
located in different regions of our country (8 in the south and 6 in the east). The analysis has shown
that the fluctuation of the mean valuation of each question of the survey in a determined room is a
pattern that is repeated approximately in all of the studied spaces, forming a band of approximately
1 variation point in each answer and that contains to all rooms. The limits of this band would
indicate the ends of the subjective response associated to concert halls
Elaboration process of a subjective response test from listeners and Musical experts, as a tool of evaluation of the musical perception in Concerts halls, auditoria and theatres
In order to tackle the study related to the requirements for musical audition in concert halls, some
measurements and analyses of objective acoustic parameters have been made. However, the
subjective evaluation of the sensation that the values of these acoustic parameters have on the
listeners, can only be shown by means of a questionnaire that listeners have to answer. Such
questionnaire has been formulated in an understandable way and the questions are directly or
indirectly related to the abovementioned parameters. The aim of the present article is to present the
elaboration process of a test of subjective response addressed to the general public and to some
musical experts who have no special skills on acoustics. This study has been made in 13 auditoria,
concert rooms and theatres distributed in different Autonomous Regions of Spain.Para abordar el estudio de las exigencias para la audición musical en salas de conciertos se realiza
la medida y análisis de parámetros acústicos objetivos. Sin embargo, la valoración subjetiva de la
sensación que unos u otros valores de esos parámetros acústicos producen en la audiencia, sólo
puede ponerse de manifiesto a través de las respuestas de los oyentes a una encuesta cuyas
preguntas, formuladas de manera comprensible, estén relacionadas, directa o indirectamente, con
dichos parámetros acústicos. El objeto de este artículo es presentar el proceso de elaboración de
un test de respuesta subjetiva dirigido al público en general y a expertos musicales pero sin
formación especializada en acústica. Este estudio se ha realizado en 13 auditorios, salas de
conciertos y teatros repartidos en diferentes Comunidades Autónomas de nuestro país.
Ponencia presentada al Encuentro Ibérico de Acústica. EAA Symposium. Gandía (España). 200
Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications
Superparamagnetic iron oxide nanoparticles
can providemultiple benefits for biomedical applications
in aqueous environments such asmagnetic separation or
magnetic resonance imaging. To increase the colloidal
stability and allow subsequent reactions, the introduction
of hydrophilic functional groups onto the particles’
surface is essential. During this process, the original
coating is exchanged by preferably covalently bonded
ligands such as trialkoxysilanes. The duration of the
silane exchange reaction, which commonly takes more
than 24 h, is an important drawback for this approach. In
this paper, we present a novel method, which introduces
ultrasonication as an energy source to dramatically
accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove
the generic character, different functional groups were
introduced on the surface including polyethylene glycol
chains, carboxylic acid, amine, and thiol groups. Their
colloidal stability in various aqueous buffer solutions as
well as human plasma and serum was investigated to
allow implementation in biomedical and sensing
applications.status: publishe
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