2,638 research outputs found
A 2D hydrodynamic-sedimentological model for gravel-bed rivers. Part I: theory and validation
This paper presents a novel 2D-depth average model especially developed for gravel-bed rivers, named Lican-Leufú (Lican=pebble and Leufu=river, in Mapuche’s language, the native inhabitants of Central Patagonia, Argentina). The model consists of three components: a hydrodynamic, a sedimentological, and a morphological model. The flow of water is described by the depth-averaged Reynolds equations for unsteady, free-surface, shallow water flows. It includes the standard k-e model for turbulence closure. Sediment transport can be divided in different size classes (sand-gravel mixture) and the equilibrium approach is used for Exner’s equation. The amour layer is also included in the structure of the model and the surface grain size distribution is also allowed to evolve. The model simulates bank slides that enable channel widening. Models predictions were tested against a flume experiment where a static armour layer was developed under conditions of sediment starvations and general good agreements were found: the model predicted adequately the sediment transport, grain size of transported material, final armour grain size distribution and bed elevation
An Exploratory Study on the Influence of Psychopathological Risk and Impulsivity on BMI and Perceived Quality of Life in Obese Patients
The present study aimed to assess the psychological profiles of adult male and female obese patients, as well as to verify the possible influence of their psychopathological risk and impulsivity on their body mass index (BMI) and perceived quality of life. A total of 64 obese subjects accessing a center for care of their obesity were assessed through anthropometric and psychometric measurements. All anthropometric measures in men were higher than in women, while in turn, women showed higher psychopathological symptoms. Furthermore, the symptoms of somatization and psychoticism were predictors for a higher BMI in men, but there was no effect of psychopathological symptoms on the perceived quality of life (QoL) of male subjects. Moreover, in women, somatization and attentional impulsivity were predictors for a higher BMI, whereas no correlation was found between their psychopathological risk and perceived QoL. The results of regression analysis underlined that somatization is a “core” psychopathological symptom in obese subjects regardless of their sex, which is a potential predictor for a higher BMI. The psychological difficulties of the subjects had no effect on their perceived QoL, suggesting that they find it difficult to reflect on the impact that obesity has on their life
Reduced sleep duration affects body composition, dietary intake and quality of life in obese subjects.
Purpose Sleep duration has emerged as a crucial factor
affecting body weight and feeding behaviour. The aim of
our study was to explore the relationship among sleep
duration, body composition, dietary intake, and quality of
life (QoL) in obese subjects.
Methods Body composition was assessed by DXA.
‘‘Sensewear Armband’’ was used to evaluate sleep duration.
SF-36 questionnaire was used to evaluate quality of
life (QoL). A 3-day dietary record was administered.
Subjects were divided into 2 groups: sleep
duration[and B300 min/day.
Results 137 subjects (105 women and 32 men), age:
49.8 ± 12.4 years, BMI: 38.6 ± 6.7 kg/m2, were enrolled.
Sleep duration was B300 min in 30.6 % of subjects.
Absolute and relative fat mass (FM) (40.5 ± 9 vs.
36.5 ± 9.1 kg; 40.2 ± 4.7 vs. 36.9 ± 5.6 %), and truncal
fat mass (19.2 ± 6.1 vs. 16.6 ± 5 kg; 38.6 ± 5.3 vs.
35.2 ± 5.5 %) were higher in subjects sleeping B300 min
when compared to their counterparts (all p.05),
whereas just a tendency towards a higher BMI was
observed (p = 0.077). Even though energy intake was not
different between groups, subjects sleeping B300 min
reported a higher carbohydrate consumption per day
(51.8 ± 5.1 vs. 48.4 ± 9.2 %, p = 0.038). SF-36 total
score was lower in subjects sleeping B300 min
(34.2 ± 17.8 vs. 41.4 ± 12.9, p = 0.025). Sleep duration
was negatively associated with FM (r = -0.25, p = 0.01)
and SF-36 total score (r = -0.31, p.001). The inverse
association between sleep duration and SF-36 total score
was confirmed by the regression analysis after adjustment
for BMI and fat mass (R = 0.43, R2 = 0.19, p = 0.012).
Conclusion Reduced sleep duration negatively influences
body composition, macronutrient intake, and QoL in obese
subjects
Small-scale spatial distribution of COVID-19-related excess mortality
Mortality due to massive events like the COVID-19 pandemic is underestimated because of several reasons, among which the impossibility to track all positive cases and the inadequacy of coding systems are presumably the most relevant. Therefore, the most affordable method to estimate COVID-19-related mortality is excess mortality (EM). Very often, though, EM is calculated on large spatial units that may entail different EM patterns and without stratifying deaths by age or sex, while, especially in the case of epidemics, it is important to identify the areas that suffered a higher death toll or that were spared. We developed the Stata COVID19_EM.ado procedure that estimates EM within municipalities in six subgroups defined by sex and age class using official data provided by ISTAT (Italian National Statistics Bureau) on deaths occurred from 2015 to 2020. Using simple linear regression models, we estimated the mortality trend in each age-and-sex subgroup and obtained the expected deaths of 2020 by extrapolating the linear trend. The results are then displayed using choropleth maps. Subsequently, local autocorrelation maps, which allow to appreciate the presence of local clusters of high or low EM, may be obtained using an R procedure that we developed.We focused on estimating excess mortality in small-scale spatial units (municipalities) and in population strata defined by age and sex.This method gives a deeper insight on excess mortality than summary figures at regional or national level, enabling to identify the local areas that suffered the most and the high-risk population subgroups within them.This type of analysis could be replicated on different time frames, which might correspond to successive epidemic waves, as well as to periods in which containment measures were enforced and for different age classes; moreover, it could be applied in every instance of mortality crisis within a region or a country. (C) 2021 Published by Elsevier B.V
Tracking log displacement during floods in the Tagliamento River using RFID and GPS tracker devices
Large pieces of in-channel wood can exert an important role on the ecological and morphological properties of gravel-bed rivers. On the other side, when transported during flood events, large wood can become a source of risk for sensitive structures such as bridges. However, wood displacement and velocity in river systems are still poorly understood, especially in large gravel-bed rivers. This study focuses on log transport in a valley reach of Tagliamento River (Italy). Log displacement during flood events of different magnitudes recorded from June 2010 to October 2011 has been analysed thanks to the installation of 113 radio frequency identification (RFID) tags and 42 GPS tracker devices in logs of different dimensions. Recovery rates of logs equipped with RFID and GPS trackers were about 43% and 42%, respectively. The GPS devices allowed us to analyse in details the log displacement and transport overtime, indicating a higher log entrainment during rising limb of hydrographs. The threshold for the entrainment of logs from low bars is around 40% of bankfull water stage. No clear relationship was found between the peak of flood and log displacement length and velocity. However, log displacement length and velocity appear significantly correlated to the ratio between the peak of flow and the water stage exceeding the flow duration curve for 25% of time (i.e. the ratio hmax/h25 ratio). Log deposition was observed to occur at the peak flow, and logs transported during ordinary events are preferably deposited on low bars. This study reveals the potentials of GPS tracker devices to monitor the entrainment and movements of logs in large gravel-bed rivers during floods. These observations could be useful for better planning of river management practices and strategies involving the use of large wood pieces and could help for calibrating wood budgets at the reach scale
Acute conversion of patient-derived Duchenne muscular dystrophy iPSC into myotubes reveals constitutive and inducible over-activation of TGFβ-dependent pro-fibrotic signaling
Background
In Duchenne muscular dystrophy (DMD), DYSTROPHIN deficiency exposes myofibers to repeated cycles of contraction/degeneration, ultimately leading to muscle loss and replacement by fibrotic tissue. DMD pathology is typically exacerbated by excessive secretion of TGFβ and consequent accumulation of pro-fibrotic components of the extra-cellular matrix (ECM), which in turn impairs compensatory regeneration and complicates the efficacy of therapeutic strategies. It is currently unclear whether DMD skeletal muscle fibers directly contribute to excessive activation of TGFβ. Development of skeletal myofibers from DMD patient-derived induced pluripotent stem cells (iPSC), as an “in dish” model of disease, can be exploited to determine the myofiber contribution to pathogenic TGFβ signaling in DMD and might provide a screening platform for the identification of anti-fibrotic interventions in DMD.
Methods
We describe a rapid and efficient method for the generation of contractile human skeletal muscle cells from DMD patient-derived hiPSC, based on the inducible expression of MyoD and BAF60C (encoded by SMARCD3 gene), using an enhanced version of piggyBac (epB) transposone vectors. DMD iPSC-derived myotubes were tested as an “in dish” disease model and exposed to environmental and mechanical cues that recapitulate salient pathological features of DMD.
Results
We show that DMD iPSC-derived myotubes exhibit a constitutive activation of TGFβ-SMAD2/3 signaling. High-content screening (HCS)-based quantification of nuclear phosphorylated SMAD2/3 signal revealed that DMD iPSC-derived myotubes also exhibit increased activation of the TGFβ-SMAD2/3 signaling following exposure to either recombinant TGFβ or electrical pacing-induced contraction.
Conclusions
Acute conversion of DMD patient-derived iPSC into skeletal muscles, by the ectopic expression of MyoD and BAF60C, provides a rapid and reliable protocol for an “in dish” DMD model that recapitulates key pathogenic features of disease pathology, such as the constitutive activation of the TGFβ/SMAD signaling as well as the deregulated response to pathogenic stimuli, e.g., ECM-derived signals or mechanical cues. Thus, this model is suitable for the identification of new therapeutic targets in DMD patient-specific muscles
Systematic analysis of mRNA 5' coding sequence incompleteness in Danio rerio: an automated EST-based approach
<p>Abstract</p> <p>Background</p> <p>All standard methods for cDNA cloning are affected by a potential inability to effectively clone the 5' region of mRNA. The aim of this work was to estimate mRNA open reading frame (ORF) 5' region sequence completeness in the model organism <it>Danio rerio </it>(zebrafish).</p> <p>Results</p> <p>We implemented a novel automated approach (<it>5'_ORF_Extender</it>) that systematically compares available expressed sequence tags (ESTs) with all the zebrafish experimentally determined mRNA sequences, identifies additional sequence stretches at 5' region and scans for the presence of all conditions needed to define a new, extended putative ORF. Our software was able to identify 285 (3.3%) mRNAs with putatively incomplete ORFs at 5' region and, in three example cases selected (<it>selt1a</it>, <it>unc119.2</it>, <it>nppa</it>), the extended coding region at 5' end was cloned by reverse transcription-polymerase chain reaction (RT-PCR).</p> <p>Conclusion</p> <p>The implemented method, which could also be useful for the analysis of other genomes, allowed us to describe the relevance of the "5' end mRNA artifact" problem for genomic annotation and functional genomic experiment design in zebrafish.</p> <p>Open peer review</p> <p>This article was reviewed by Alexey V. Kochetov (nominated by Mikhail Gelfand), Shamil Sunyaev, and Gáspár Jékely. For the full reviews, please go to the Reviewers' Comments section.</p
Acumulaciones de detritos leñosos en un cauce de montaña de Tierra del Fuego: análisis de la movilidad y de los efectos hidromorfológicos
This work reports on the geomorphic role of large wood pieces and jams in a third order mountain stream located in Southern Tierra del Fuego (Argentina), and draining an old-growth nothofagus forested basin not influenced by beaver damming activity. Even if the in-stream number of wood pieces (2,300) is comparable to that observed in other climatic areas, the slow growth of the nothofagus forest causes a lower wood abundance in terms of volumetric load (121 m3 ha–1). Due to the relatively small dimensions of the large wood pieces located inside bankfull edges (83% of the total surveyed pieces), almost the 70% of them demonstrated to have been transported by runoff and 6% derived from bank erosion or landslides. Wood jams exert a significant influence on the channel morphology, being responsible for the creation of 30% of pools. The geomorphic influence of LW jams is also exerted by a considerable sediment storing capacity (about 1,750 m3). The LW-forced pool volume is strongly and positively correlated to the height of the LW jam. The results confirm that dead wood pieces, especially when organized in jams, play an important geomorphic role also in sub-Antarctic streams. The amount of large wood pieces quantified in the study site represents reference values for the assessment of the geomorphic effects of beaver activity in other Tierra del Fuego streams
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