Three examples where the specific surface area of snow increased over time

Snow on the ground impacts climate through its high albedo and affects atmospheric composition through its ability to adsorb chemical compounds. The quantification of these effects requires the knowledge of the specific surface area (SSA) of snow and its rate of change. All relevant studies indicate that snow SSA decreases over time. Here, we report for the first time three cases where the SSA of snow increased over time. These are (1) the transformation of a melt-freeze crust into depth hoar, producing an increase in SSA from 3.4 to 8.8m2 kg−1. (2) The mobilization of surface snow by wind, which reduced the size of snow crystals by sublimation and fragmented them. This formed a surface snow layer with a SSA of 61m2 kg−1 from layers whose SSAs were originally 42 and 50m2 kg−1. (3) The sieving of blowing snow by a snow layer, which allowed the smallest crystals to penetrate into open spaces in the snow, leading to an SSA increase from 32 to 61m2 kg−1. We discuss that other mechanisms for SSA increase are possible. Overall, SSA increases are probably not rare. They lead to enhanced uptake of chemical compounds and to increases in snow albedo, and their inclusion in relevant chemical and climate models deserves consideration

Argo salinity: bias and uncertainty evaluation

Argo salinity is a key set of in situ ocean measurements for many scientific applications. However, use of the raw, unadjusted salinity data should be done with caution as they may contain bias from various instrument problems, most significant being from sensor calibration drift in the conductivity cells. For example, inclusion of biased but unadjusted Argo salinity has been shown to lead to spurious results in the global sea level estimates. Argo delayed-mode salinity data are data that have been evaluated and, if needed, adjusted for sensor drift. These delayed-mode data represent an improvement over the raw data because of the reduced bias, the detailed quality control flags, and the provision of uncertainty estimates. Such improvement may help researchers in scientific applications that are sensitive to salinity errors. Both the raw data and the delayed-mode data can be accessed via https://doi.org/10.17882/42182 (Argo, 2022). In this paper, we first describe the Argo delayed-mode process. The bias in the raw salinity data is then analyzed by using the adjustments that have been applied in delayed mode. There was an increase in salty bias in the raw Argo data beginning around 2015 and peaking during 2017–2018. This salty bias is expected to decrease in the coming years as the underlying manufacturer problem has likely been resolved. The best ways to use Argo data to ensure that the instrument bias is filtered out are then described. Finally, a validation of the Argo delayed-mode salinity dataset is carried out to quantify residual errors and regional variations in uncertainty. These results reinforce the need for continual re-evaluation of this global dataset.</p

Machine Learning Based Fall Detector with a Sensorized Tip

Fall detection has become an area of interest in recent years, as quick response to these events is critical to reduce the morbidity and mortality rate. In order to ensure proper fall detection, several technologies have been developed, including vision system, environmental detection systems, and wearable sensor based systems. However, in elderly or impaired people, it has been shown that the implementation of sensors in Assistive Devices for Walking, such as crutches or canes, can also be a promising alternative. In this work, a Support Vector Machine (SVM) based Fall Detection system is proposed, which uses the data provided by a Sensorized Tip which can be attached to different Assistive Devices for Walking (ADW). Unlike other approaches, the developed one is able to differentiate the fall of the ADW from the fall of the user. For that purpose, the developed Fall Detector uses two modules connected in series. The first one detects all falls, while the second differentiates between user and ADW falls. The proposed approach is validated in a set of experimental tests carried out by healthy volunteers that have simulated different falls. In addition, a comparative analysis is carried out by comparing the performance of the Sensorized Tip based Fall Detector and a state-of-the-art commercial accelerometer system. Results demonstrate that the proposed approach provides high Fall Detection Ratios (over 90%), similar or higher to wearable-sensor based approaches

The structure of blocks with a Klein four defect group

We prove Erdmann’s conjecture [16] stating that every block with a Klein four defect group has a simple module with trivial source, and deduce from this that Puig’s finiteness conjecture holds for source algebras of blocks with a Klein four defect group. The proof uses the classification of finite simple groups

Epithelial Keratins Modulate cMet Expression and Signaling and Promote InlB-Mediated Listeria monocytogenes Infection of HeLa Cells

The host cytoskeleton is a major target for bacterial pathogens during infection. In particular, pathogens usurp the actin cytoskeleton function to strongly adhere to the host cell surface, to induce plasma membrane remodeling allowing invasion and to spread from cell to cell and disseminate to the whole organism. Keratins are cytoskeletal proteins that are the major components of intermediate filaments in epithelial cells however, their role in bacterial infection has been disregarded. Here we investigate the role of the major epithelial keratins, keratins 8 and 18 (K8 and K18), in the cellular infection by Listeria monocytogenes. We found that K8 and K18 are required for successful InlB/cMet-dependent L. monocytogenes infection, but are dispensable for InlA/E-cadherin-mediated invasion. Both K8 and K18 accumulate at InlB-mediated internalization sites following actin recruitment and modulate actin dynamics at those sites. We also reveal the key role of K8 and K18 in HGF-induced signaling which occurs downstream the activation of cMet. Strikingly, we show here that K18, and at a less extent K8, controls the expression of cMet and other surface receptors such TfR and integrin β1, by promoting the stability of their corresponding transcripts. Together, our results reveal novel functions for major epithelial keratins in the modulation of actin dynamics at the bacterial entry sites and in the control of surface receptors mRNA stability and expression.This work received funding from Norte-01-0145-FEDER-000012 - Structured program on bioengineered therapies for infectious diseases and tissue regeneration, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). Publication Fees were supported by ICBAS, University of Porto. RC received an FCT Doctoral Fellowship (SFRH/BD/90607/2012) and IP-C a FCT Post-Doctoral Fellowship (SFRH/BPD/107901/2015) through FCT/MEC co-funded by QREN and POPH (Programa Operacional Potencial Humano). SS was supported by FCT Investigator program (COMPETE, POPH, and FCT). We thank IBMC facilities for technical assistance

Assembled PTO based on an array of double-acting hydraulic cylinders for WECs: From Conceptual Design to an Adjusted Detailed Model

All Wave Energy Converters (WECs) based on wave activated bodies comprises a Power Take- Off (PTO) system among other subsystems like the reaction mechanism, the supervisor of the system and the electrical generator. One of the most applied PTO systems consists of oil high pressure hydraulic devices. These devices are able to apply high forces, to store large quantities of energy through accumulators and to provide smoother power output to the motor coupled to a generator. In these systems the poor efficiency and the oil leakages contaminating the environment are considered main drawbacks. Despite of this, they are widely used in several promising WECs with the aim of optimizing the harvested wave energy along the time. The initial challenge to absorb an oscillating movement of ±30º at 5rad/s as a maximum angular speed absorbing up to 16000Nm from a specific WEC, led to the development of a simplified hydraulic model before manufacturing a PTO prototype to be verified in a Test Bench (Figure 1). The experimental results of PTO under different conditions have been used to adjust a full detailed PTO Model using Mathworks® software platform. This work presents a patented oil high pressure hydraulic PTO prototype based on an array of four double-acting hydraulic cylinders. This prototype has been designed and completely modelled as a proof concept at 1:4 scale being able to apply a variable Coulomb type damping torque through the activation of each hydraulic cylinder independently and through the modification of geometrical parameters easily. The complete model of the PTO has been accurately tuned up through adjustment of model parameters using the results of the experimental tests. This will allow the study of control strategies to optimize the extracted wave energy from a specific WEC, like point-absorbers

Composite resins : A review of the materials and clinical indications

The aim of this work is to present the different components of the composites currently used in dentistry and furnish dentists with a basis that can provide criteria for choosing one or another to suit their therapeutic requirements. Most composites used in dentistry are hybrid materials, so-called because they are composed of polymer groups reinforced by an inorganic phase of glass fillers with different compositions, particle sizes and fill percentages. Flowable or condensable composites have attempted to provide an answer to certain functional requirements, although they have not been too successful at improving properties. Turning to polymerisation initiators, both halogen lamps, whether conventional or high intensity, and LED curing lights which provide a gradual increase in light intensity are very useful for reducing shrinkage of the composite material. The clinical choice of a composite must consider whether priority should be given to mechanical or aesthetic requirements: if mechanical considerations are paramount the material with the greatest volume of filler will be chosen; if aesthetic considerations predominate, particle size will be the most important factor. Additional components such as opaques and tints make it possible to improve the aesthetic results. Equally, the spread of other therapeutic procedures, such as tooth bleaching, has made it necessary to design composite materials in shades that are suitable for the special colour situations found in teeth treated by these methods

CINÉTICA DE HIDROXILACIÓN Y OXIDACIÓN DE COMPUESTOS FENÓLICOS POR POLIFENOL OXIDASA DE UVA MONASTRELL (VITIS VINIFERA)

Monastrell grape polyphenol oxidase was purified, showing both activity towards monophenols and o-diphenols. The kinetic parameters, Km and optimal temperature, were evaluated in both activities. Cresolase activity presents a particular lag period, which may be modified by the temperature, enzyme concentration, the presence of o-diphenols and substrate concentration.La enzima polifenol oxidasa ha sido purificada a partir de uva Monastrell mostrando actividad tanto en la oxidación de monofenoles (cresolasa) como en la de o-difenoles (catecolasa). Los parámetros cinéticos, Km y temperatura óptima, han sido evaluados en ambas actividades. La actividad cresolasa presenta un período de retardo característico, que puede ser modificado por la temperatura, la concentración de enzima, la presencia de o-difenoles y la concentración de sustrato

Eliminación de Cu2+ de efluentes acuosos

Se presenta un estudio de eliminaci&oacute;n de Cu2+ por adsorci&oacute;n sobre pasta de celulosa al sulfato. Se han obtenido las isotermas de equilibrio a la temperatura de 30'0&deg; C y pH 4,5 y 6, respectivamente. En los tres casos las curvas se ajustan a funciones del tipo Koble-Corrigan, con n = 2. Para los mismos pH y concentraciones de 1, 3, 5, 7 y 10 ppm de Cu2+ se han trazado los frentes de adsorci&oacute;n. Finalmente, siguiendo el tratamiento de Michaels se han calculado, a partir de dichos frentes, las distintas caracter&iacute;sticas del proceso: LUB, V, f, G, Ntoc, y Htoo, respectivamente