369 research outputs found
Advancing the understanding of adaptive capacity of social‐ecological systems to absorb climate extremes
A regression framework to head-circumference delineation from US fetal images
Background and Objectives: Measuring head-circumference (HC) length from ultrasound (US) images is a crucial clinical task to assess fetus growth. To lower intra- and inter-operator variability in HC length measuring, several computer-assisted solutions have been proposed in the years. Recently, a large number of deep-learning approaches is addressing the problem of HC delineation through the segmentation of the whole fetal head via convolutional neural networks (CNNs). Since the task is a edge-delineation problem, we propose a different strategy based on regression CNNs. Methods: The proposed framework consists of a region-proposal CNN for head localization and centering, and a regression CNN for accurately delineate the HC. The first CNN is trained exploiting transfer learning, while we propose a training strategy for the regression CNN based on distance fields. Results: The framework was tested on the HC18 Challenge dataset, which consists of 999 training and 335 testing images. A mean absolute difference of 1.90 ( ± 1.76) mm and a Dice similarity coefficient of 97.75 ( ± 1.32) % were achieved, overcoming approaches in the literature. Conclusions: The experimental results showed the effectiveness of the proposed framework, proving its potential in supporting clinicians during the clinical practice
Efficacy of different antifouling treatments for seawater cooling systems
In an industrial seawater cooling system, the effects of three different antifouling treatments, viz. sodium
hypochlorite (NaClO), aliphatic amines (Mexel1432) and UV radiation, on the characteristics of the fouling formed
were evaluated. For this study a portable pilot plant, as a side-stream monitoring system and seawater cooling
system, was employed. The pilot plant simulated a power plant steam condenser, having four titanium tubes under
different treatment patterns, where fouling progression could be monitored. The nature of the fouling obtained was
chiefly inorganic, showing a clear dependence on the antifouling treatment employed. After 72 days the tubes under
treatment showed a reduction in the heat transfer resistance (R) of around 70% for NaClO, 48% for aliphatic
amines and 55% for UV, with respect to the untreated tube. The use of a logistic model was very useful for
predicting the fouling progression and the maximum asymptotic value of the increment in the heat transfer
resistance (DRmax). The apparent thermal conductivity (l) of the fouling layer showed a direct relationship with the
percentage of organic matter in the collected fouling. The characteristics and mode of action of the different
treatments used led to fouling with diverse physicochemical properties
Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers
[EN] The macromolecular dynamics of dendronized copolymer membranes (PECHs), obtained by chemical modification of poly(epichlorohydrin) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, was investigated. In response to a thermal treatment during membrane preparation, these copolymers show an ability to change their shape, achieve orientation, and slightly crystallize, which was also observed by CP-MAS NMR, XRD, and DSC. The phenomenon was deeply analyzed by dielectric thermal analysis. The dielectric spectra show the influence of several factors such as the number of dendritic side groups, the orientation, their self-assembling dendrons, and the molecular mobility. The dielectric spectra present a sub-Tg dielectric relaxation, labelled as gamma, associated with the mobility of the benzyloxy substituent of the dendritic group. This mobility is not related to the percentage of these lateral chains but is somewhat hindered by the orientation of the dendritic groups. Unlike other less complex polymers, the crystallization was dismantled before the appearance of the glass transition (alpha(Tg)). Only after that, clearing transition (alpha(Clear)) can be observed. The PECHs were flexible and offered a high free volume, despite presenting a high degree of modifications. However, the molecular mobility is not independent in each phase and the self-assembling dendrons can be eventually fine-tuned according to the percentage of grafted groups.This research was funded by the Spanish Ministry of Science, Innovation and Universities, grant POLYDECARBOCELL (ENE2017-86711-C3-1-R, ENE2017-86711-C3-3-R).Teruel Juanes, R.; Pascual-Jose, B.; Graf, R.; Reina, JA.; Giamberini, M.; Ribes-Greus, A. (2021). Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers. Polymers. 13(12):1-19. https://doi.org/10.3390/polym13121961119131
Progress in grassland cover conservation in southern European mountains by 2020: a transboundary assessment in the Iberian Peninsula with satellite observations (2002–2019)
Conservation and policy agendas, such as the European Biodiversity strategy, Aichi biodiversity (target 5) and Common Agriculture Policy (CAP), are overlooking the progress made in mountain grassland cover conservation by 2020, which has significant socio-ecological implications to Europe. However, because the existing data near 2020 is scarce, the shifting character of mountain grasslands remains poorly characterized, and even less is known about the conservation outcomes because of different governance regimes and map uncertainty. Our study used Landsat satellite imagery over a transboundary mountain region in the northwestern Iberian Peninsula (Peneda-Gerês) to shed light on these aspects. Supervised classifications with a multiple classifier ensemble approach (MCE) were performed, with post classification comparison of maps established and bias-corrected to identify the trajectory in grassland cover, including protected and unprotected governance regimes. By analysing class-allocation (Shannon entropy), creating 95% confidence intervals for the area estimates, and evaluating the class-allocation thematic accuracy relationship, we characterized uncertainty in the findings. The bias-corrected estimates suggest that the positive progress claimed internationally by 2020 was not achieved. Our null hypothesis to declare a positive progress (at least equality in the proportion of grassland cover of 2019 and 2002) was rejected (X2 = 1972.1, df = 1, p p = 0.0001, n = 708) suggesting a relationship between the quality of pixel assignment and thematic accuracy. We therefore encourage a post-2020 conservation and policy action to safeguard mountain grasslands by enhancing the role of protected governance regimes. To reduce uncertainty, grassland gain mapping requires additional remote sensing research to find the most adequate spatial and temporal data resolution to retrieve this process.This work was supported by the Portuguese FCT—Fundação para a Ciência e Teconologia
in the framework of the ATM Junior researcher contract DL57/2016/CP1442/CP0005 and funding attributed to CEG-IGOT Research Unit (UIDB/00295/2020 and UIDP/00295/2020). Claudia
Carvalho-Santos is supported by the “Contrato-Programa” UIDP/04050/2020 funded by FCT. We also
acknowledge ECOPOTENTIAL (Improving Future Ecosystem Benefits Through Earth Observations)—
European framework programme H2020 for research and innovation- grant agreement Nº 641762
Molecular Mobility in Oriented and Unoriented Membranes Based on Poly[2-(Aziridin-1-yl)ethanol]
Unoriented and oriented membranes based on dendronized polymers and copolymers obtained by chemical modification of poly[2-(aziridin-1-yl) ethanol] (PAZE) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy]benzoate were considered. DSC, XRD, CP-MAS NMR and DETA, contribute to characterize the tendency to crystallize, the molecular mobility of the benzyloxy substituent, the dendritic liquid crystalline group and the clearing transition. The orientation of the mesogenic chain somewhat hindered this molecular motion, especially in the full substituted PAZE. The fragility, free volume and thermal expansion coefficients of these membranes near the glass transition are related to the orientation and the addition of the dendritic groups. PAZE-based membranes combine both order and mobility on a supramolecular and macroscopic level, controlled by the dendritic group and the thermal orientation, and open the possibility of preparing membranes with proper channel mobility that promotes selective ionic transport
\u3ci\u3eAquastella gen. nov.\u3c/i\u3e: A new genus of saprolegniaceous oomycete rotifer parasites related to \u3ci\u3eAphanomyces\u3c/i\u3e, with unique sporangial outgrowths
The oomycete genus Aquastella is described to accommodate two new species of parasites of rotifers observed in Brooktrout Lake, New York State, USA. Three rotifer species – Keratella taurocephala,Polyarthra vulgaris, and Ploesoma truncatum – were infected, and this is the first report of oomycete infection in these species. Aquastella attenuata was specific to K. taurocephala and Aquastella aciculariswas specific to P. vulgaris and P. truncatum. The occurrence of infections correlated with peak host population densities and rotifers were infected in the upper layers of the water column. Sequencing of 18S rRNA and phylogenetic analysis of both species placed them within the order Saprolegniales, in a clade closely related to Aphanomyces. The Aquastella species were morphologically distinct from other rotifer parasites as the developing sporangia penetrated out through the host body following its death to produce unique tapered outgrowths. Aquastella attenuata produced long, narrow, tapering, finger-like outgrowths, whilst A. acicularis produced shorter, spike-like outgrowths. We hypothesize that the outgrowths serve to deter predation and slow descent in the water column. Spore cleavage was intrasporangial with spore release through exit tubes. Aquastella attenuata produced primary zoospores, whereas A. acicularisreleased spherical primary aplanospores, more typical of other genera in the Aphanomyces clade
Estudio del espectro de relajaciones dieléctricas y la conductividad en cristales líquidos poliméricos columnares
Las actuales membranas en el mercado para pilas de combustible alimentadas por bioalcoholes
presentan el fenómeno del crossover o flujo cruzado, responsable de la pérdida de eficiencia de la
pila. Los polímeros obtenidos como una modificación química de la poliepiclorhidrina (PECH) y
de la poli(1-(2-hidroxietil)aziridina) (PAZE) suponen un importante avance, puesto que se utiliza
la capacidad coordinativa del oxígeno y del nitrógeno frente a los cationes para transportar los
protones. En este trabajo se ha sintetizado y caracterizado el comportamiento dieléctrico de
diferentes cristales líquidos columnares poliméricos obtenidos por modificación de estos
polímeros [1-2]. Estos polímeros modificados contienen grupos con una estructura cónico-plana
que se ensamblan formando una columna de canal iónico, cuyo centro está formado por una
cadena continua hidrofílica de poliéter o poliamina, que actúa como transportador de protones.
Para obtener el espectro de relajaciones dieléctricas y la conductividad iónica se realizaron
medidas en el rango de frecuencias f = 10-2/107 Hz y desde -150ºC hasta la temperatura de
isotropización, que depende de la estructura química del polímero. El espectro de relajaciones de
los polímeros se representan en términos de la permitividad dieléctrica compleja, ε’ y ε’’, la
tangente de pérdidas, tan(δ), y el módulo eléctrico, M* y se observan las relajaciones
correspondientes a fenómenos de movilidad local en este tipo de cristales líquidos [3]. Estos
polímeros exhiben una conductividad protónica que alcanza valores similares a los que muestran
las membranas comerciales de Nafión. Los resultados obtenidos indican que se puede conseguir
un alto grado de selectividad de los protones frente a otras moléculas como el agua y el metanol,
eliminando en gran medida el fenómeno del crossover. Por tanto es posible diseñar nuevas
estrategias para preparar electrolitos anisótropos aplicables a pilas de combustible alimentadas
por bioalcoholes, donde los mecanismos de conductividad se controlan a través de la formación
de mesofases columnares.Los autores quieren agradecer al Ministerio de Economía y Competitividad por su apoyo a través
de los proyectos de investigación ENE2011-28735-C02-01 (DOMEPOL) y CTQC2013-46825-R
y la Generalitat Valenciana a través de los programas GRISOLIAP/2012/056 y
APOSTD/2014/041
Carbon dioxide fluxes in Alpine grasslands at the Nivolet Plain, Gran Paradiso National Park, Italy 2017–2023
The version of record of this article, first published in [Scientific Data], is available online at Publisher’s website: http://dx.doi.org/10.1038/s41597-024-03374-1We introduce a georeferenced dataset of Net Ecosystem Exchange (NEE), Ecosystem Respiration (ER) and meteo-climatic variables (air and soil temperature, air relative humidity, soil volumetric water content, pressure, and solar irradiance) collected at the Nivolet Plain in Gran Paradiso National Park (GPNP), western Italian Alps, from 2017 to 2023. NEE and ER are derived by measuring the temporal variation of CO2 concentration obtained by the enclosed chamber method. We used a customised portable non-steady-state dynamic flux chamber, paired with an InfraRed Gas Analyser (IRGA) and a portable weather station, measuring CO2 fluxes at a number of points (around 20 per site and per day) within five different sites during the snow-free season (June to October). Sites are located within the same hydrological basin and have different geological substrates: carbonate rocks (site CARB), gneiss (GNE), glacial deposits (GLA, EC), alluvial sediments (AL). This dataset provides relevant and often missing information on high-altitude mountain ecosystems and enables new comparisons with other similar sites, modelling developments and validation of remote sensing data.This work was funded by the H2020 projects ECOPOTENTIAL (grant number: 641762), e-shape (grant number: 820852), eLTER PLUS (grant number: 871128), by the Italian National Biodiversity Future Center (NBFC), National Recovery and Resilience Plan (NRRP; mission 4, component 2, investment 1.4 of the Ministry of University and Research, funded by the European Union–NextGenerationEU; project code CN00000033), and by the ITINERIS NRRP Italian infrastructure project (project code No. IR0000032 - ESFRI Environment)
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