1,212 research outputs found
Thin film instability with thermal noise
We study the effects of stochastic thermal fluctuations on the instability of
the free surface of a flat liquid film upon a solid substrate. These
fluctuations are represented as a standard Brownian motion that can be added to
the deterministic equation for the film thickness within the lubrication
approximation. Here, we consider that while the noise term is white in time, it
is coloured in space. This allows for the introduction of a finite correlation
length in the description of the randomized intermolecular interaction.
Together with the expected spatial periodicity of the flow, we find a
dimensionless parameter, , that accounts for the relative importance of
the spatial correlation. We perform here the linear stability analysis (LSA) of
the film under the influence of both terms, and find the corresponding power
spectra for the amplitudes of the normal modes of the instability. We compare
this theoretical result with the numerical simulations of the complete
non-linear problem, and find a good agreement for early times. For late times,
we find that the stochastic LSA predictions on the dominant wavelength remains
basically valid. We also use the theoretical spectra to fit experimental data
from a nanometric melted copper film, and find the corresponding times of the
evolution as well as the values of the parameter,
Comparative Assessment of the Mineral Content of a Latin American Raw Sausage Made by Traditional or Non-Traditional Processes
Taxonomic composition and ecological characteristics of the endemic flora of the lower Duero Basin (Iberian Peninsula)
The taxonomical composition and an analysis of four ecological characteristics
of the 46 endemic species occurring in the lower Duero Basin (CW
Iberian Peninsula) have been made. A comparative analysis of the results
reveals that this endemic flora does not comply with the general patterns previously
observed in other floras. Predominant life forms are hemicryptophytes
(43%) and chamaephytes (22%). As far seed-dispersal is concerned, 54% of the
endemic species lack any noteworthy adaptative feature. 89% of the endemic
species are pollinated by animals (mostly by insects) and only 1 species is dioecious.
Following binary classification of the above characteristics have been
used to plot statistically significant associations.La composition taxonomique et une analyse de quatre caracteristiques
ecologiques des 46 especes endemiques rencontrees dans le bassin inferieur
du Duero (CW de Ia Peninsula lberique) ont ete realisees. Une analyse
comparative des resultats montre que cette !lore endemique ne correspond pas
aux schemas generaux observes precedemment dans d'autres flares. Les
formes biologiques predominantes son! les Mmicryptophytes (43%) et les chamephytes
(22%). En ce qui conceme le mode de dispersion des diaspores, 54%
des especes endemiques son! depourvues de tout aspect adaptatif particulier.
89% des especes endemiques son! pollinisees par des animaux (essentiellement
des insectes) et une seule espece est dioique. En se basant sur une classification
binaire, les caracteristiques precedentes ont eta utilisees pour
representer graphiquement les associations statistiquement significatives.We would like to thank Dr. Tyteca for the translation of the French texts. This research was
supported by a grant from Castilla y Leon Autonomous Government (SA 037/02)info:eu-repo/semantics/publishedVersio
Conservation status of the threatened Iberian Peninsula narrow endemic Antirrhinum lopesianum Rothm. (Scrophulariaceae)
Antirrhinum lopesianum Rothm. is a narrow endemic of the Lusitan Duriensean biogeographical sector (central western Spain
and north-eastern Portugal). The species is listed as threatened in several Spanish documents, although it does not figure as
such in any Portuguese document. This paper provides a detailed study of its distribution, estimates of the sizes of its
populations, the threats it faces, and its current conservation status. The total number of individuals thought to exist is only
768, distributed along the valley of the River Duero on the Spanish – Portuguese border (562, 71.2%), and in the Portuguese
Sabor River valley (206, 26.8%). The main threat to the species is loss of habitat: about one third of the Iberian populations
can be considered threatened; one population containing 37.6% of all these plants (289) is severely threatened. To
determine the Area of Occupancy and the Extent of Occurrence, an exhaustive bibliographical survey was carried out, and
herbarium specimens deposited in several institutions were revised. It is, therefore, classifiable as Critically Endangered in
Portugal and Endangered in Spai
La relación entre la falta de sueño, el ocio sedentario y el sobrepeso infantil
En esta investigación se estudio, a través del path analysis,
la relación entre los hábitos de ocio sedentario, sueño y el índice
de Masa Corporal (IMC). Participó una muestra de 72 alumnos,
41 chicas y 31 chicos, de cuarto de primaria con una edad
comprendida entre los 9 y los 10 años y medio. Para ello se
realizó una entrevista individual en la que se preguntaba a los
niños los programas que veían cada uno de los días de la semana
y los juegos con los que jugaban con la consola y el ordenador.
Los resultados pusieron de manifiesto que los niños que duermen
menos emplean más tiempo realizando alguna forma de ocio
sedentario y que esto se relaciona a su vez con un IMC más
elevado. Se discuten las implicaciones sobre el estudio del estilo
de vida y sobrepeso infantil.The objective of this research was to analyse the relations
between short sleeping, sedentary leisure and childhood
overweight using the path analysis. The sample consisted of 72
participants aged 9 to 10 and half years, 41 girls and 31 boys.
One individual interview was used in order to evaluate these
variables. The results pointed out that participants with short
sleeping spent more time watching TV and playing videogames
o using computer and in the same way this type of leisure is
related with a higher Body Mass Index. The implications on the
study of childhood lifestyle and overweight are discussed
Increased Presentation of Diabetic Ketoacidosis and Changes in Age and Month of Type 1 Diabetes at Onset during the COVID-19 Pandemic in Spain
COVID-19; Aparició de la diabetis; Diabetis tipus 1COVID-19; Aparición de diabetes; Diabetes tipo 1COVID-19; Diabetes onset; Type 1diabetesObjective: To assess the impact of the COVID-19 pandemic and lockdown measures on the presenting characteristics (age at diagnosis, severity, monthly distribution) of newly diagnosed type 1 diabetes in Spanish children. Research Design and Methods: An ambispective observational multicenter study was conducted in nine Spanish tertiary-level hospitals between January 2015 and March 2021. Inclusion criteria: new cases of type 1 diabetes in children (0–14 years) recording age, sex, date of diagnosis, presence of diabetic ketoacidosis (DKA) at onset, and severity of DKA. Data were compared before and during the pandemic. Results: We registered 1444 new cases of type 1 diabetes in children: 1085 in the pre-pandemic period (2015–2019) and 359 during the pandemic (2020–March 2021). There was a significant increase in the group aged ≤4 years in the pandemic period (chi-squared = 10.986, df 2, p = 0.0041). In 2020–2021, cases of DKA increased significantly by 12% (95% CI: 7.2–20.4%), with a higher percentage of moderate and severe DKA, although this increase was not significant. In 2020, there was a sharp decrease in the number of cases in March, with a progressive increase from May through November, higher than in the same months of the period 2015–2019, highlighting the increase in the number of cases in June, September, and November. The first three months of 2021 showed a different trend to that observed both in the years 2015–2019 and in 2020, with a marked increase in the number of cases. Conclusions: A change in monthly distribution was described, with an increase in DKA at onset of type 1 diabetes. No differences were found in severity, although there were differences in the age distribution, with an increase in the number of cases in children under 4 years of age
Monitoring the performance of wastewater treatment plants for organic matter removal using excitation-emission matrix fluorescence
This study has assessed the usefulness of excitation-emission matrix fluorescence (EEMF) as a fast and simple
analytical technique to track changes in dissolved organic matter (DOM) during the sequence of treatment in
wastewater treatment plants (WWTPs). Three different industrial wastewaters and treatment plants have been
studied in this work: an industrial park wastewater treated in an independent line at the Burgos WWTP (Spain), a
food industry wastewater (crisps and snacks manufacturing) that was treated in a MBR (Membrane Biological
Reactor) pilot plant (University of Burgos) and a municipal landfill leachate treated in a physicochemical
treatment plant within the same landfill.
Removal percentages for the wastewater organic matter at each stage of the treatment plants were successfully
obtained by monitoring the main fluorescence peaks: protein-like peaks (tryptophan-like peaks T1, T2 and
tyrosine-like peaks B1, B2), humic-like peaks (fulvic-like peak A and humic-like peak C) and microbially-derived
peak M. Therefore, EEMF readily allows the assessment of the reactivity of the different types of organic matter
towards specific treatments, such as clarification, biodegradation, filtration, etc. Among the wastewaters studied,
the food industry wastewater exhibited the greater diversity of fluorescence peaks (B1, B2, T1, T2, A1, A2 and M)
whereas the landfill leachate only showed the presence of humic substances (mainly humic-like peak C). This
study has demonstrated that EEMF is a useful and user-friendly technique to monitor the performance of
wastewater treatment plants for organic matter removal, allowing a rapid response to potential problems in the
treatment
LAL regulators SCO0877 and SCO7173 as pleiotropic modulators of phosphate starvation response and actinorhodin biosynthesis in Streptomyces coelicolor
[EN] LAL regulators (Large ATP-binding regulators of the LuxR family) constitute a poorly studied family of transcriptional regulators. Several regulators of this class have been identified in antibiotic and other secondary metabolite gene clusters from actinomycetes, thus they have been considered pathway-specific regulators. In this study we have obtained two disruption mutants of LAL genes from S. coelicolor (Δ0877 and Δ7173). Both mutants were deficient in the production of the polyketide antibiotic actinorhodin, and antibiotic production was restored upon gene complementation of the mutants. The use of whole-genome DNA microarrays and quantitative PCRs enabled the analysis of the transcriptome of both mutants in comparison with the wild type. Our results indicate that the LAL regulators under study act globally affecting various cellular processes, and amongst them the phosphate starvation response and the biosynthesis of the blue-pigmented antibiotic actinorhodin. Both regulators act as negative modulators of the expression of the two-component phoRP system and as positive regulators of actinorhodin biosynthesis. To our knowledge this is the first characterization of LAL regulators with wide implications in Streptomyces metabolismSIThis work was supported by the Spanish Ministerio de Ciencia e Innovación (BIO2007-67585 and BIO2010-19911 to JFA); and the Junta de Castilla y León (Grupo de Excelencia GR117). FPU fellowships of the Ministerio de Ciencia e Innovación (AP2005-3644 to JSA, AP2007-02055 to T.D.P.); a fellowship from the University of León (to SMG); and a contract from the Junta de Castilla y León (E-24-2009-0053914 to CMV). The funders had no role in study design, data collection and analysis, decision to publish, or presentation of the manuscript
Elucidation of the chemical role of the pyroclastic materials on the state of conservation of mural paintings from Pompeii
Pyroclastic strata have always been thought to protect the archaeological remains of the Vesuvian area (Italy), hence allowing their conservation throughout the centuries. In this work, we demonstrate that they constitute a potential threat for the conservation state of the mural paintings of Pompeii. The ions that could be leached from them and the ion‐rich groundwater coming from the volcanic soil/rocks may contribute to salt crystallisation. Thermodynamic modelling not only allowed to predict which salts can precipitate from such leaching events but also assisted the identification of additional sources of sulfates and alkali metals to explain the formation of the sulfates identified in efflorescences from the mural paintings of Pompeii. For the future, fluorine, mainly related to a volcanic origin, can be proposed as a marker to monitor the extent of the impact in the mural paintings of Pompeii in situ
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