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The maximum velocity of dewetting encodes sufficient information on the hydrodynamics of the wetting process to enable the local dynamic contact angle at the molecular scale, θ, to be determined from the apparent contact angle measured experimentally at much larger scales, θEffective models of wetting dynamics need to account for differing channels of dissipation. One such model was recently verified by large-scale molecular dynamics (MD). It combines the 2-parameter molecular-kinetic theory of dynamic wetting (MKT), which attributes the velocity-dependence of θ to dissipation at the contact line, with the Cox-Voinov hydrodynamic (HD) model. The latter attributes the difference between θ and θData available to test the procedure are sparce, but comparisons with the MD results and those from three experimental studies are encouraging. Near perfect agreement is achieved with the simulations, where both θ and θ

Sulfidic mine wastes have the potential to generate acid mine drainage (AMD) and release acid leachates containing high levels of iron, sulfate and potentially toxic elements (PTEs). Soils receiving AMD discharges are generally devoid of vegetation. Only a few metal-tolerant plant species can survive under such adverse soil conditions. This work investigates two plant species, Nicotiana glauca and Euphorbia segetalis, that have successfully colonized an AMD-impacted wetland area in south-western Spain. The uptake of PTEs from the soil by roots and their transfer and accumulation in the above-ground biomass were quantified. Results showed that these pioneer plants grew in patches of neutral soil within the wasteland despite the high concentrations of PTEs in the rhizosphere soil (up to: 613 mg kg-1 As, 18.7 mg kg-1 Cd, 6370 mg kg-1 Cu, 2210 mg kg-1 Pb and 5250 mg kg-1 Zn). The target organs of As, Cu and Pb accumulation were: root > leaf > stem in N. glauca, and root > stem > leaf in E. segetalis. Zinc and Cd showed a significant decrease in roots relative to aerial parts of N. glauca, and Co was preferentially partitioned in stems of N. glauca and leaves of E. segetalis. The soil-plant transfer coefficient values of PTEs in all parts of both plants were well below unity with the only exception of Cd in leaves of N. glauca (1.254), suggesting that roots acted as a barrier limiting the uptake of PTEs by plants. Interestingly, under the same soil conditions, N. glauca absorbed Cd in considerable proportions from soil and accumulated it in its leaves, while E. segetalis was not effective in transferring PTEs from roots shoots except for Co. In conclusion, soil pH and plant-related factors greatly influence the stabilization of PTE in the rhizospheric soil and produce inconsistencies in PTE phytoavailability. The findings of this study provide criteria to assist in natural remediation in other legacy contaminated sites worldwide., Funding for open access publishing: Universidad de Sevilla/CBUA. This research was partially supported by the Regional Government of Andalusia (Spain) and the European Regional Development Fund Andalusia 2014–2020 through the Project P-18-TP-3503.

Introduction In the surgical field, information about operations is traditionally written down in the informed consent form, which often uses technical language that is difficult for patients to understand. Even when accompanied by verbal explanations, patients only seem to retain between 20–60% of the details. With the purpose of improving the effectiveness of communication with our patients during the surgical process, from the Day Surgery Unit of our hospital we have developed a protocol to provide an audio-visual aid to the information supplied. Methods Two explanatory videos were developed for inguinal hernia repair and pilonidal cyst surgery, which were given to the patients under the care of our service using a QR code, both in the preoperative consultation and at discharge. The videos included simple explanations regarding the disease, procedure and postoperative care, in terms easily understandable to the general population. Subsequently, during postoperative follow-ups, feedback from the first 105 patients was collected. Results Results showed that, out of the first 105 patients who received the QR code, 72 watched the video, and of those, 100% were satisfied with the quality of the information provided and recognised that it improved their understanding of the procedure. Conclusions The use of new technologies, and, more specifically, of audio-visual support, could help to improve the comprehension of information received throughout surgical procedures, since it enables its repeated viewing and its sharing with relatives, which could improve the patient's overall satisfaction.

Introduction Liposarcoma represents one of the most frequent types of soft tissue sarcomas, constituting a heterogeneous group of lesions. There are four different subtypes: well-differentiated; dedifferentiated; myxoid and pleomorphic. Its main locations are the retroperitoneum, extremities, trunk and the cervical area. Clinical case A 90-year-old male with a pleomorphic liposarcoma in the left thigh in 2012, local recurrence from a dedifferentiated liposarcoma in 2018 and 2021, presented to our emergency department with abdominal pain and vomiting. CT scan revealed an image of intestinal intussusception in the distal jejunum due to a 5 cm intraluminal polyp. Emergency laparotomy revealed a change in the distal jejunum caliber caused by the intussusception finding a 5 cm polypoid mass. We made an intestinal resection with a L-L anastomosis. Histopathological examination showed evidence of metastasis from dedifferentiated liposarcoma. Discussion A sarcoma is a malignant tumor, an infrequent type of cancer from connective tissue. The liposarcoma is the most frequent subtype and the dedifferentiated type can occur as dedifferentiation from other subtypes. The most common sites of metastasis include the lung, liver, and bone. Metastasis to the small bowel is rare with few reported cases. Intestinal intussusception is an infrequent cause of mechanical intestinal obstruction in adults. Etiology is diverse and it is often caused by benign lesions in the small bowel and malignant lesions in the colon. The diagnostic technique of choice is the CT scan with contrast and treatment usually requires surgery. Intestinal reduction is controversial because of the risk of perforation or tumor spread.

This paper makes use of a combination of FLEXPART-WRF simulations forced with ERA5 and the CESM2 model—incorporated in the CMIP6 project—to infer a series of changes over the present century in the behavior of the landfalling atmospheric rivers (ARs) arriving to the Iberian Peninsula. In addition, future changes in the intensity and position of their main moisture sources are studied. In overall terms, there is a noticeable increase in the amount of moisture transported by ARs in the study region, particularly accentuated by the end of the century. However, no significant changes in the number of events are observed. A northward shift of both the mean position of the ARs as well as their main sources of moisture is also detected, particularly for the end of the century, and in the summer and fall months. In relation to the latter, an increase in the contribution of moisture contribution is also observed, quantitatively compatible with Clausius-Clapeyron amplification. Agencia Estatal de Investigación | Ref. PID2021-122314OB-I00 Xunta de Galicia | Ref. ED481A‐2020/193 Xunta de Galicia | Ref. ED431C 2021/44 Universidade de Vigo/CISUG

Se presentan características sedimentológicas y geoquímicas de sedimentos marinos superficiales recientes de la bahía de Paracas, como parte de los Proyectos “Estudio Integrado de la Dinámica de los Procesos Físicos y Biogeoquímicos en Ecosistemas del Borde Costero” y “Fondo Para el Medio Ambiente Mundial”, desarrollados durante 2013, 2014 y 2015. Los sedimentos recientes de la bahía de Paracas corresponden a texturas limo arcilloso, arcilla limosa y limo arenoso, que están asociados a bajas intensidades de corrientes. Los sedimentos arenosos se registraron cerca de la línea de costa y de la desembocadura del río Pisco, la presencia de grava es muy escasa (

Hypothesis Molecular dynamics (MD) may be used to investigate the velocity dependence of both the microscopic and apparent dynamic contact angles ( θ m and θ app ). Methods We use large-scale MD to explore the steady displacement of a water-like liquid bridge between two molecularly-smooth solid plates under the influence of an external force F 0 . A coarse-grained model of water reduces the computational demand and the solid-liquid affinity is varied to adjust the equilibrium contact angle θ 0 . Protocols are devised to measure θ m and θ app as a function of contact-line velocity U cl . Findings For all θ 0 , θ m is velocity-dependent and consistent with the molecular-kinetic theory of dynamic wetting (MKT). However, θ app diverges from θ m as F 0 is increased, especially at the receding meniscus. The behavior of θ app follows that predicted by Voinov: (θapp)3 = (θm)3 + 9Ca·ln(L/Lm), where C a is the capillary number and L and L m are suitably-chosen macroscopic and microscopic length scales. For each θ 0 , there is a critical velocity U crit and contact angle θ crit at which θ app → 0 and the receding meniscus deposits a liquid film. Setting θ app = 0 , θ m = θ crit and U cl = U crit in the Voinov equation yields the value of L / L m . The predicted values of θ app then agree well with those measured from the simulations. Since θ m obeys the MKT, we have, therefore, demonstrated the utility of the combined model of dynamic wetting proposed by Petrov and Petrov.

Hypothesis In previous work [J.-C. Fernandez-Toledano, T. D. Blake, J. De Coninck, J. Colloid Interface Sci. 540 (2019) 322–329], **we used molecular dynamics (MD) to show that the thermal oscillations of a contact line formed between a liquid and a solid at equilibrium may be interpreted in terms of an overdamped 1-D Langevin harmonic oscillator. The variance of the contact-line position and the rate of damping of its self-correlation function enabled us to determine the coefficient of contact-line friction ζ and so predict the dynamics of wetting. We now propose that the same approach may be applied to a moving contact line. Methods We use the same MD system as before, a liquid bridge formed between two solid plates, but now we move the plates at a steady velocity U plate in opposite directions to generate advancing and receding contact lines and their associated dynamic contact angles θ d . The fluctuations of the contact-line positions and the dynamic contact angles are then recorded and analyzed for a range of plate velocities and solid-liquid interaction. Findings We confirm that the fluctuations of a moving contact line may also be interpreted in terms of a 1-D harmonic oscillator and derive a Langevin expression analogous to that obtained for the equilibrium case, but with the harmonic term centered about the mean location of the dynamic contact line x d , rather than its equilibrium position x 0 , and a fluctuating capillary force arising from the fluctuations of the dynamic contact angle around θ d , rather than the equilibrium angle θ 0 . We also confirm a direct relationship between the variance of the fluctuations over the length of contact line considered L y , the time decay of the oscillations, and the friction ζ . In addition, we demonstrate a new relationship for our systems between the distance to equilibrium x d - x 0 and the out of equilibrium capillary force γ L cos θ 0 - cos θ d , where γ L is the surface tension of the liquid, and show that neither the variance of the fluctuations nor their time decay depend on U plate . Our analysis yields values of ζ nearly identical to those obtained for simulations of spreading drops confirming the common nature of the dissipation mechanism at the contact line.

Hypothesis The thermal fluctuations of the three-phase contact line formed between a liquid and a solid at equilibrium can be used to determine key parameters that control dynamic wetting. Methods We use large-scale molecular dynamics simulations and Lennard-Jones potentials to model a liquid bridge between two molecularly smooth solid surfaces and study the positional fluctuations of the contact lines so formed as a function of the solid–liquid interaction. Findings We show that the fluctuations have a Gaussian distribution and may be modelled as an overdamped one-dimensional Langevin oscillator. Our analysis allows us to extract the coefficients of friction per unit length of the contact lines ζ , which arise from the collective interaction of the contact-line’s constituent liquid atoms with each other and the solid surface. We then compare these coefficients with those obtained by measuring the dynamic contact angle as a function of contact-line speed in independent simulations and applying the molecular-kinetic theory of dynamic wetting. We find excellent agreement between the two, with the same dependence on solid–liquid interaction and, therefore, the equilibrium contact angle θ 0 . As well as providing further evidence for the underlying validity of the molecular-kinetic model, our results suggest that it should be possible to predict the dynamics of wetting and, in particular, the velocity-dependence of the local, microscopic dynamic contact angle, by experimentally measuring the fluctuations of the contact line of a capillary system at equilibrium. This would circumvent the need to measure the microscopic dynamic contact angle directly.

INTRODUCTION Internal hernias caused by broad ligament defects are an infrequent cause of bowel obstruction. These defects may be congenital or acquired mainly by gynecological antecedents. Small bowel is the most common affected and the diagnosis is difficult due to nonspecific symptoms and absences of characteristic radiological signs. MATERIAL AND METHODS We report the cases of three women aged from 43 to 56 years old, who came to the emergency with abdominal pain, vomiting and bloating of hours duration. One patient has a history of laparoscopic appendectomy, the rest of them with no surgical history. In all of the cases, x-rays showed dilatation of small bowel loops and air-fluid levels and the abdominal TC revealed a generalized distention of bowel loops with transition point in the terminal ileum with no identifiable cause compatible with small bowel obstruction. RESULTS We decided to perform an urgent surgery with an exploratory laparotomy in one case and the rest by laparoscopic approach, finding an internal hernia occasioned by incarceration of small bowel through a broad ligament defect. In all cases, the hernia content was liberated without evidence of ischemia with no need for intestinal resection, and the defect was closed. All patients had a favourable postoperative course without complications. DISCUSSION Broad ligament defects are a rare cause of internal hernias. These are difficult to diagnose clinically as well as radiologically for an absence of characteristic signs. A high level of clinical suspicion allows early diagnosis and the treatment should be performed as soon as possible to reduce the chances of intestinal necrosis.

INTRODUCTION Perforated gastroduodenal ulcer represents a common surgical emergency and is associated with a morbimortality close to 40-50%. HP infection, tobacco and alcohol and some socioeconomic aspects represent the most commonly described risk factors. MATERIAL AND METHODS A descriptive and retrospective study was performed between 2018-2020. A total of 40 patients with a history of gastroduodenal perforation were selected. Data corresponding to: sex, age, ulcer location, treatment, tobacco and alcohol consumption, HP infection (presence or not of eradicating treatment) and other potential risk factors were collected and analysed. The aim of the study is to assess how new lifestyle changes, the evolution and improvement in the management of PH infection and the general decrease in smoking have modified the classic profile of patients with gastroduodenal perforations. RESULTS Gastroduodenal perforations predominated in the fifth/sixth decade of life (mean age 59 years). Although a predominance in men is described in the literature, in our sample no significant sex differences were found (1:1 ratio). The most frequent location was duodenal and the reference surgical treatment was primary suture + epipoplasty. Only one third of the patients had a known history of peptic ulcer. CONCLUSIONS Gastroduodenal perforations are a major problem for the on-call surgeon. It is essential to know the current risk factors and their potential relationship with morbimortality and postoperative evolution in order to guarantee the optimal management of these patients.

INTRODUCTION The results obtained from the establishment of a multimodal rehabilitation program in elective colorectal surgery by a multidisciplinary team at our center are presented. Protocols are carried out to achieve optimization of perioperative care and the analysis of the rates of complications and morbidity and mortality. MATERIAL AND METHODS Through a retrospective study, a control group of patients who underwent elective colorectal surgery prior to the implantation of the rehabilitation program, included during a period from May and October 2018, with a total of 68 patients, were compared with the group of optimized patients, who were operated between December 2018 and June 2019, with a total of 80 patients. RESULTS The readmission rate 30 days after discharge between the two groups is analyzed, showing a decrease in the multimodal rehabilitation group, with a readmission rate of 5.9%, compared to the control group, which was 8.8%. A decrease was observed in both surgical complications (35.3%) and medical complications (22.1%) in the multimodal rehabilitation group compared to the control group. A decrease in the mortality rate is observed in the multimodal rehabilitation group, being 1.5% with respect to the control group, which was 2.9%. CONCLUSIONS The multimodal rehabilitation system is a feasible and safe method that requires the implementation of protocols that must be carried out by a multidisciplinary team, and that presents satisfactory results with improved morbidity and mortality.

INTRODUCTION Anastomosis dehiscence is one of the most serious complications in colorectal surgery, influenced by many factors, especially the anastomotic ischemia. Intraoperative Indocyanine Green (ICG) Fluorescence Angiography allows to assess the vascular perfusion of the ends anastomotic and anastomosis thus seeking to decrease the number of sutures failure. MATERIAL AND METHODS A retrospective and descriptive study of patients undergoing colorectal surgery in our centre using intraoperative indocyanine green fluorescence angiography. We analysed a total of 45 patients, including 40 cases of colorectal cancer and 5 cases with a benign pathology (4 diverticular disease and 1 Crohńs disease). RESULTS After administration of ICG, the site of resection was changed in 6 cases due to bad perfusion findings. 5 patients presented anastomotic leakage during the postoperative period. The medium hospital stay length was 10 days, increasing to 29,2 days medium stay in patients with postoperative dehiscence respect to 7’72 days in patients without postoperative complications. No deaths or adverse reactions associated with the ICG were detected. CONCLUSIONS The technique with ICG seems to be a promising tool for the colorectal surgery as a predictor of suture failure. It allows a reduction of hospital stay length and postoperative morbidity and mortality from this cause and it can serve as a good help for making decisions in the course of a surgery.

For the safety and continuity of service in industrial electrical systems, the availability of transformers is essential. For this reason, it is necessary to develop intelligent fault diagnosis techniques to reduce repair and maintenance costs. Recently, several methods have been developed that use artificial intelligence techniques such as neural networks, support vector machines, hybrid techniques, etc., for the diagnosis of faults in power transformers using gas analysis. These methods, although they present very good results, encounter restrictions to determine the precise moment before the occurrence of multiple fault of small magnitude and are difficult to implement in practice. This document proposes a method to diagnose multiple incipient faults in a power transformer using fuzzy logic. The proposal, based on historical data from the composition of the gases dissolved in the oil, achieves a performance in the classification of multiple incipient fault of 98.3%. With reliable samples of dissolved gas, it guarantees an overall rate of accuracy in detecting incipient faults that is superior to that obtained by the most successful conventional methods in the industry. The proposal does not encounter generalization difficulties and constitutes a simple solution that allows determining the state of the transformer in service without affecting the continuity of the electricity supply.

espanolEsta investigacion esta encaminada a estudiar las capacidades de carga o limites aceptables de cambio en la cantidad de visitantes que puede soportar una actividad ecoturistica en una zona determinada para contribuir a la conservacion del medioambiente mediante un desarrollo sostenible. En este caso, el estudio se realizo en la zona sur de la Isla de la Juventud (Cuba), concretamente en el poblado de Cocodrilo. Para ello se utilizo una metodologia mixta basada en metodos descriptivos, analitico-sintetico y logico abstracto, asi como mediante el analisis experimental basado en el metodo desarrollado por Cifuentes en 1992 y mejorado en 1999. La aportacion de esta investigacion ha sido la obtencion de datos sobre el mayor impacto de visitantes o capacidad de carga que puede soportar la zona en las caminatas ecoturisticas realizadas por el turismo nacional e internacional, a fin de poder analizar las posibilidades economicas que este tipo de actividades pueden aportar, conservando su caracter de economia sostenible y sin que se comprometa el medioambiente para que las futuras generaciones puedan disfrutar y admirar la belleza de los recursos naturales existentes. Palabras clave: Ecoturismo; medioambiente; deporte; senderismo; Cuba. EnglishRegulation of Ecotourism in the Jacksonville, Island Youth (Cuba). The aim of this research is to study the carrying capacity or limits of acceptable change in the number of visitors that an ecotourism activity in a specific area can bear, to contribute to the environmental conservation through sustainable development. In this case, the area chosen for this study corresponds to the southern region of the Isle of Youth (Cuba), particularly in the so-called Jacksonville. A mixed methodology was used, combining different descriptive methods: Analytic-Synthetic and logical abstract methods, as well as the experimental analysis based on the method developed by Cifuentes in 1992 and improved in 1999. The greatest contribution of this work is the data provision on the biggest visitor impact, or the carrying capacity that this area can bear in the ecotourism walking tours by domestic and international tourists. This research aims to analyze the financial gains that this type of activities can provide, keeping its character for a sustainable economic growth without causing any impacts on the environment so that future generations can enjoy and admire the beauty of the existing natural resources. Key words: Ecotourism; environment; sport; hiking; Cuba.

Large-scale molecular dynamic simulations are used to investigate the velocity dependence of the dynamic contact angle of a waterlike liquid on a flat carbonlike solid surface and to extract the coefficients of contact-line friction. It is shown that the same coefficients are obtained from a Langevin model of contact-line fluctuations at equilibrium, without any additional theoretical interpretation or model. A mechanistic link between the coefficients of slip and contact-line friction is also confirmed.

For a pendant drop whose contact line is a circle of radius $r_0$, we derive the relation $mg\sin\alpha={\pi\over2}\gamma r_0\,(\cos\theta^{\rm min}-\cos\theta^{\rm max})$ at first order in the Bond number, where $\theta^{\rm min}$ and $\theta^{\rm max}$ are the contact angles at the back (uphill) and at the front (downhill), $m$ is the mass of the drop and $\gamma$ the surface tension of the liquid. The Bond (or E\"otv\"os) number is taken as $Bo=mg/(2r_0\gamma)$. The tilt angle $\alpha$ may increase from $\alpha=0$ (sessile drop) to $\alpha=\pi/2$ (drop pinned on vertical wall) to $\alpha=\pi$ (drop pendant from ceiling). The focus will be on pendant drops with $\alpha=\pi/2$ and $\alpha=3\pi/4$. The drop profile is computed exactly, in the same approximation. Results are compared with surface evolver simulations, showing good agreement up to about $Bo=1.2$, corresponding for example to hemispherical water droplets of volume up to about $50\,\mu$L. An explicit formula for each contact angle $\theta^{\rm min}$ and $\theta^{\rm max}$ is also given and compared with the almost exact surface evolver values., Comment: 8 pages, 5 figures

Assess whether the Asthma, Sport and Health (ASAH) programme taught by teachers improves asthmatics' quality of life, asthma knowledge, and reduces school absenteeism.Randomised cluster trial parallel group.2293 students (203 asthmatic) in the Intervention School group (IS) and 2214 in the Comparison School (CS) (224 asthmatic) belonging to primary school.Implementation of the educational programme "Asthma, Sport and Health" at grade schools, taught by physical education teachers.Quality of life according to the Pediatric Asthma Quality of Life Questionnaire (PAQLQ).Asthma knowledge, asthma control, school absenteeism.After implementing the programme in the IS group, global quality of life improved significantly (p0.001) as did their domains, symptoms (p0.001), emotional function (p0.001) and activity limitations (p0.01), while in the CS group improvement was seen in global life quality (p0.01) without any significant changes in the domains for emotional function and activity limitations. Asthma knowledge only increased in IS, among asthmatic students from 16.51 (CI 95% 16.04-16.98) to 18.16 (CI 95% 17.69-18.62) (p0.001) and students without asthma from 15.49 (CI95% 15.36-15.63) to 17.50 (CI95% 17.36-17.64) (p0.001). The multiple regression analysis showed that quality of life and its domains depend on asthma knowledge and above all, having well-controlled asthma. We found no decrease in school absenteeism.The ASAH programme improved certain quality of life aspects regarding asthma (emotional function and limitation of activities) and asthma knowledge, but it failed to reduce school absenteeism NCT01607749.

Using large-scale molecular dynamics simulations, we model a 9.2 nm liquid bridge between two solid plates having a regular hexagonal lattice and analyse the forces acting at the various interfaces for a range of liquid-solid interactions. Our objective is to study the mechanical equilibrium of the system, especially that at the three-phase contact line. We confirm previous MD studies that have shown that the internal pressure inside the liquid is given precisely by the Laplace contribution and that the solid exerts a global force at the contact line in agreement with Young's equation, validating it down to the nanometre scale, which we quantify. In addition, we confirm that the force exerted by the liquid on the solid has the expected normal component equal to γlv sin θ0, where γlv is the surface tension of the liquid and θ0 is the equilibrium contact angle measured on the scale of the meniscus. Recent thermodynamic arguments predict that the tangential force exerted by the liquid on the solid should be equal to the work of adhesion expressed as Wa0 = γlv(1 + cos θ0). However, we find that this is true only when any layering of the liquid molecules close to liquid-solid interface is negligible. The force significantly exceeds this value when strong layering is present.

Hypothesis The contact line pinning that appears in a flow coating process over substrates patterned with chemical or physical heterogeneities has been recently applied to deposit micro- and nanoparticles with great precision. However, the mechanism underlying pinning of a receding contact line at the nanoscale is not yet well understood. In the case of a contact line pinned at a chemical heterogeneity, we hypothesise that it is possible to establish a relation between the pinning time, the contact line velocity and the liquid/plate/heterogeneity affinity that can help to optimize particle deposition. Methods We use large-scale molecular dynamic (MD) simulations of a finite liquid bridge formed between two parallel, non–identical, smooth solid plates. The top plate slides relative to the bottom plate inducing a displacement of the four different contact lines of the liquid bridge. The introduction of a chemical heterogeneity on the bottom plate by modifying locally the liquid–solid affinity provokes the transient pinning of the contact line in contact with the bottom substrate. By means of this simple MD simulation, we can study the mechanism of contact line pinning and its relation with the liquid/heterogeneity affinity and the contact line velocity. Additionally, we compare this mechanism with the case of the receding contact line pinned on a physical heterogeneity (a simple step discontinuity). Findings We propose an analytical model that predicts the values of the dynamic contact angles in the general case of a capillary liquid bridge confined between two parallel plates with different wettabilities versus the relative velocity of the top plate. These predictions are successfully validated by the results of the large–scale MD simulations. The model allows thus to predict the value of the dynamic contact angles for the different contact lines of the system versus the relative speed of the moving plate. Once the chemical heterogeneity is introduced in the bottom plate, we show that when the receding contact line reaches the patch it remains temporarily pinned while the receding contact angle evolves with time. Once the receding angle reaches the value of the equilibrium contact angle of the patch, the receding contact line overcomes pinning. A geometrical model able to predict the pinning time is proposed and validated by our MD simulations. The pinning time depends not only on the relative plate velocity and plate wettability properties but also on the separation distance between the plates confining the capillary bridge. The model can consequently be used to select the substrate wettability or meniscus geometry suitable to impose the pinning time required for specific applications.

Using large scale molecular dynamics simulations, we study in detail the impact of nanometer droplets of low viscosity on flat substrates versus the wettability of the solid plate. The comparison between the molecular dynamics simulations and different macroscopic models reveals that most of these models do not correspond to the simulation results at the nanoscale, in particular for the maximal contact diameter during the nanodroplet impact (${D}_{\mathrm{max}}$). We have developed a new model for ${D}_{\mathrm{max}}$ that is in agreement with the simulation data and also takes into account the effects of the liquid-solid wettability. We also propose a new scaling for the time required to reach the maximal contact diameter ${t}_{\mathrm{max}}$ with respect to the impact velocity, which is also in agreement with the observations. With the new model for ${D}_{\mathrm{max}}$ plus the scaling found for ${t}_{\mathrm{max}}$, we present a master curve collapsing the evolution of the nanometer drop contact diameter during impact for different wettabilities and different impact velocities. We believe our results may help in designing better nanoprinters since they provide an estimation of the maximum impact velocities required to obtain a smooth and homogenous coverage of the surfaces without dry spots.

Hypothesis That the behavior of sliding drops at the nanoscale mirrors that seen in macroscopic experiments, that the local microscopic contact angle is velocity dependent in a way that is consistent with the molecular-kinetic theory (MKT), and that observations at this scale shed light on the pearling transition seen with larger drops. Methods We use large-scale molecular dynamics (MD) to model a nanodrop of liquid sliding across a solid surface under the influence of an external force. The simulations enable us to extract the shape of the drop, details of flow within the drop and the local dynamic contact angle at all points around its periphery. Findings Our results confirm the macroscopic observation that the dynamic contact angle at all points around the drop is a function of the velocity of the contact line normal to itself, U cm s in ϕ , where U cm is the velocity of the drop’s center of mass and ϕ is the slope of the contact line with respect to the direction of travel. Flow within the drop agrees with that observed on the surface of macroscopic drops. If slip between the first layer of liquid molecules and the solid surface is accounted for, the velocity-dependence of the dynamic contact angle is identical with that found previous MD simulations of spreading drops, and consistent with the MKT. If the external force is increased beyond a certain point, the drop elongates and a neck appears between the front and rear of the drop, which separate into two distinct zones. This appears to be the onset of the pearling transition at the tip of a macroscopic drop. The receding contact angle at the tip of the drop is far removed from its equilibrium value but non-zero and approaches a more-or-less constant critical value as the transition progresses.

The mean magnetization (MM) approximation is undoubtedly the most widely used approximation in magnetorheology both from theoretical and simulation perspectives. According to this, spherical magnetizable particles under field can be replaced by effective dipole moments m placed at their center with strength m = V(p)⟨M(p)⟩. Here V(p) and ⟨M(p)⟩ are the volume and mean (average) magnetization of the particles, respectively. In spite of being extensively used, there is not a mathematical justification to do so in most cases. In this manuscript, we test this approximation using experiments, theories and simulations, for a wide range of magnetic field strengths and particle loadings, in both conventional magnetorheological fluids (CMRFs) and inverse ferrofluids (IFFs). Results demonstrate that the MM approximation is applicable in IFFs for a very wide range of field strengths (up to external fields of 265 kA m(-1)) and particle loadings (up to 20 vol%). For CMRFs, the MM approximation is only applicable in two particular circumstances; in magnetic saturation or in infinite dilution.

La coordinacion motriz es un proceso evolutivo complejo de adquisicion progresiva. La edad optima para la adquisicion de esos procesos coordinativos es de6 a11 anos (Educacion Primaria). El objetivo del presente estudio es disenar y validar un instrumento que permita evaluar el nivel de coordinacion motriz del alumnado.Metodo: Los sujetos son alumnado de Primaria en centros publicos. Muestreo por conveniencia, con una muestra total de 2512 sujetos. Instrumento: Test cualitativo de observacion y evaluacion objetiva de la ejecucion de la habilidad desarrollada en 7 tareas.Resultados: La Consistencia interna (Alfa de Cronbach 0.827), estabilidad temporal (coeficiente correlacion: 0.99) y concordancia inter-observadores (coeficiente correlacion: 0.95). La validez se comprobo mediante la opinion intuitiva de expertos, siendo la opinion mayoritariamente favorable.Conclusion: El test 3JS es un instrumento fiable, valido y eficaz para medir el desarrollo de la coordinacion motriz en el alumnado de 6 a 12 anos.PALABRAS CLAVE: Coordinacion motriz, Evaluacion, Educacion Fisica. ABSTRACTMotor coordination is a complex evolutionary process which is gradually acquired. The optimum age for the achievement of these coordination processes is between 6 and 11 years old (Primary Education).The aim of this study is to design and validate a tool which will allow assessing the motor coordination level of the students.Method: Subjects and Sample. Students from Primary Education public schools. ‘Convenience’ sampling, with a total of 2512 subjects.Tool: Qualitative observation test and objective evaluation of the implementation of the abilities developed in 7 tasks.Results: Reliability: Internal Consistency (Cronbach Alpha 0.827), test-retest reliability (correlation coefficient; 0.99) and inter-observer agreement (correlation coefficient; 0.95). Validity has been verified by the experts’ intuitive perception, issuing a largely favourable opinion.Conclusion: The 3JS test is a reliable, valid and effective tool for measuring the motor coordination development in students between 6 and 12 years old.KEY WORDS: Motor coordination, Evaluation, Physical Education.

We investigate model magnetorheological (MR) fluids (inverse ferrofluids) under both steady and dynamic oscillatory shear. Analytical theories, particle-level simulations, and magnetorheometry are used in an attempt to obtain universal master curves. Steady shear flow data can be collapsed when plotted as a function of a dimensionless Mason number. The critical Mason number associated with the transition from magnetostatic to hydrodynamic control of the suspension structure is demonstrated to linearly increase with particle concentration which is in good agreement with theories and our simulations. Experimental linear viscoelastic moduli are in good agreement with micromechanical and macroscopic models in the dilute regime. However, upon increasing particle concentration, theoretical predictions underestimate experimental data while particle-level simulations are in good agreement. The accordance with particle-level simulations suggests that the mean (average) magnetization approximation gives a good pred...

The aim of the present study is to analyse the origin and historic evolution of the so called "Urban Sports". In order to achieve this goal, a descriptive methodology has been applied by means of documenting through direct observation, using secondary sources by different authors who have been contributing their knowledge and experiences on the matter. Following the obtained results it has been established that some of the most popular Urban Sports, stripped of their regulated, more customary way of doing them, are street basketball, skating and urban cycling. These have been known to cover the needs and interests arising in certain social circles during the 20th century, as a means to improve their quality of life within their direct surroundings. In many cases moving away from federations and institutionalized practices has permitted an increase in creativity., El objetivo del presente estudio pertenece al campo histórico y el tema de revisión es analizar el origen y evolución histórica de los llamados "Deportes Urbanos". El procedimiento empleado ha sido una metodología descriptiva por medio de la documentación a través de la observación directa, utilizando fuentes secundarias por diferentes autores que han estado contribuyendo con sus conocimientos y experiencias en la materia. Los resultados obtenidos han establecido que algunos de los más populares Deportes Urbanos practicados no de manera regulada sino libre, son: baloncesto callejero, el patinaje y el ciclismo urbano. Éstos han sabido cubrir las necesidades e intereses que han ido surgiendo en ciertos círculos sociales durante el siglo XX, como un medio para mejorar su calidad de vida dentro de su entorno inmediato, la urbe. En muchos casos el alejarse de las federaciones y las prácticas institucionalizadas ha permitido un aumento de la creatividad.

A simulation method is proposed to explore the effect of particle size polydispersity in magnetorheology including Brownian motion. The method aims to extend the classical particle-level simulation methodology developed by Klingenberg et al. [J. Chem. Phys. 91, 7888–7895 (1989)] for the case of polydisperse magnetorheological (MR) fluids. The simulation study concerns the aggregation kinetics at rest as well as the rheological behavior under start-up of steady shear and dynamic oscillatory shear tests at increasing strain amplitudes. Results demonstrate that the effect of polydispersity is only relevant at the transition regime between magnetostatic to hydrodynamic control of the suspension structure. The yielding behavior is correlated to the structural characteristics (radial distribution functions, pair correlation functions, and angular connectivities) of the MR fluids before the onset of flow. A more abrupt transition is observed for polydisperse MR fluids because interparticle links are weaker in this case if compared to monodisperse suspensions in spite of the fact that polydisperse MR fluids exhibit a larger connectivity.

Esta investigación está encaminada a estudiar las capacidades de carga o límites aceptables de cambio, en la cantidad de visitantes que puede soportar una actividad ecoturística en una zona determinada, para contribuir a la conservación del medioambiente mediante un desarrollo sostenible. En este caso, el estudio se realizó en la zona sur de la Isla de la Juventud (Cuba); concretamente en la denominada Punta del Este. Para ello se utilizó una metodología mixta basada en métodos descriptivos: analítico-sintético y lógico abstracto, así como mediante el análisis experimental basado en el método desarrollado por Cifuentes en 1992 y mejorado en 1999. La aportación de esta investigación ha sido la obtención de datos sobre el mayor impacto de visitantes, o capacidad de carga que puede soportar la zona en las caminatas ecoturísticas realizadas por el turismo nacional e internacional, a fin de poder analizar las posibilidades económicas que este tipo de actividades pueden aportar, conservando su carácter de economía sostenible y sin que se comprometa el medioambiente para que las futuras generaciones puedan disfrutar y admirar la belleza de los recursos naturales existentes. The aim of this research is to study the carrying capacity or limits of acceptable change with respect to the number of visitors that an ecotourism activity in a specific area can bear so as to contribute to environmental conservation through sustainable development. The area chosen for this study corresponds to the southern region of Isla de la Juventud (Cuba); particularly in the so-called Punta Este. A mixed methodology was used, combining different descriptive methods: Analytic-Synthetic and logical abstract methods, as well as the experimental analysis based on the method developed by Cifuentes in 1992 and improved in 1999. The principal contribution of this work is to provide data on the maximum visitor impact, or the carrying capacity that this area can bear as a result of the ecotourism walking tours undertaken by domestic and international tourists. This research aims to analyse the financial gains that these types of activities can provide, maintaining their sustainable economic nature without causing negative impacts to the environment so that future generations can enjoy and admire the beauty of the existing natural resources.

espanolL’objectiu de la recerca ha estat coneixer els recursos materials d’educacio fisica mes eficacos per millorar el desenvolupament motor gros de l’alumnat de 6 a 9 anys, en funcio del seu sexe i edat. La mostra de 982 escolars es va dividir en tres grups experimentals segons el tipus de material fungible i un grup de control. Es va emprar el test TGM-2, mitjancant un pretest i un postest despres d’una intervencio de 14 sessions. La diferencia de puntuacions directes en els dos ambits (locomotriu i control d’objectes) va ser major en els grups experimentals (p-valor EnglishThe aim of this research paper was to learn about the most effective Physical Education material resources to improve gross motor development of students aged from 6 to 9 depending on their gender and age. The sample of 982 schoolchildren was divided into three experimental groups according to the type of consumable material and a control group. The TGM-2 test procedure was used by means of a pre-test and a post-test after an intervention lasting 14 sessions. The difference in direct scores in the two areas (locomotor and object control) was higher in the experimental groups (p-value