Search

Wildfires typically transform vegetation and litter into a heterogeneous layer of ash and charred material covering the soil surface that can substantially modify the postfire hydrological and erosive response. To further elucidate the influence of postfire covering layers on sheet and concentrated flow erosion, we carried out laboratory rainfall and inflow simulations on 5 distinct soil surface conditions: bare soil, with a protective cover of char, ash, stones, and a combination thereof simulating field conditions. Each of 3 replicate simulations per treatment involved 4 runs, the first 2 simulating just rain (at 56mmhr-1) under dry andwet soil conditions and the next 2 simulating rain togetherwith inflow at high and extreme rates (0.76 and 1.4 L min-1). Overall runoff over the 4 runs together was lower for all 4 types of protective cover than for bare soil, but ash and char were clearly less effective than stones and, in particular, field conditions with runoff reductions of 25%, 23%, 40%, and 70%, respectively. Stones and field conditions were similarly effective in reducing overall erosion rates (with 47% and 77%, respectively), whereas ash and char even slightly increased overall erosion rates compared to bare soil. Ash and char were effective in reduction erosion but only during the first 2 runs under simulated rainfall. The greater effectiveness of the field conditions suggested synergistic effects between its 3 components, probably due to the stones enhancing infiltration and increasing flow resistance, thereby hampering detachment of ash and char and/or enhancing their deposition. [ABSTRACT FROM AUTHOR]

Accurate measurement of shallow flows is important for hydraulics, hydrology and water resources management. The objective of this paper is to discuss a technique for shallow flow and overland flow velocity estimation that uses infrared thermography. Laboratory flumes and different bare, vegetated and paved field surfaces were used to test the technique. Results show that shallow flow surface velocities estimated using thermal tracers and infrared technology are similar to estimates obtained using the Acoustic Doppler Velocimeter; similar results were also obtained for overland flow velocity estimates using thermography, here comparing with the dye tracer technique. The thermographic approach revealed some potential as a flow visualization technique, and leaves space for future studies and research. [ABSTRACT FROM AUTHOR]

The infrared thermography has been successfully applied as a tool for high resolution imaging in different hydrological studies. This exploratory experimental study aimed at evaluating the possibility of using infrared thermography to determine the diameter of raindrops. Rain samples are collected on a pre-heated acrylic board, which is exposed to rain during an instant, and thermograms are recorded. The area of the thermal stains ("signatures" of the raindrops) emerging on the board is measured and converted to drop diameters, applying a calibration equation. Diameters of natural raindrops estimated using this technique were compared with laser disdrometer measurements; the Nash-Sutcliffe efficiency coefficient was used for evaluating the match between the resulting histograms of drop size distribution. Results confirm the usefulness of this simple technique for sizing and counting raindrops, although it is unsatisfactory in light rain or drizzle. [ABSTRACT FROM AUTHOR]

Stabilographic analysis allows the quantification of balance by tracking center of pressure (COP) displacements in the horizontal plane during quiet standing. The aim of this study was to use pressure plates to measure descriptive stabilographic variables in Puro Sangue Lusitano horses. Center of pressure data were measured in seven horses during quiet standing using two synchronized pressures plates. For each horse, three sets of five 8-second trials were recorded with 15-minute intervals between data sets. The exported COP coordinates were converted into global coordinates defined in a global reference frame from which stabilographic variables, namely craniocaudal (CC) and mediolateral (ML) COP amplitudes and velocities, resultant COP velocity, and total path length, were calculated. The results showed no significant differences between variables for the left and right limbs. Compared with the forelimbs, the hind limbs have significantly greater values for COP ML amplitude (forelimbs: 3.2 ± 1.1 mm; hind limbs: 2.5 ± 0.5 mm), COP CC velocity (forelimbs: 1.2 ± 0.2 mm/s; hind limbs: 2.1 ± 1.0 mm/s), COP ML velocity (4.3 ± 0.9 mm/s; hind limbs: 6.5 ± 2.3 mm/s), and path length (forelimbs: 49.8 ± 8.5 mm; hind limbs: 80.3 ± 31.4 mm). The greater stability in the forelimbs may be related to their strut-like function in controlling body movements, whereas the hind limbs show a more dynamic postural response. The pressure plates used in this study, which are relatively inexpensive and more portable than force plates, are a promising tool for performing stabilographic analysis in the field. [ABSTRACT FROM AUTHOR]

ABSTRACT Flow velocity is a basic hydraulic property of surface flows and its precise calculation is necessary for process based hydrological models, such as soil erosion and rill development models, as well as for modelling sediment and solute transport by runoff. This study presents a technique based on infrared thermography to visualize very shallow flows and allow a quantitative measurement of overland flow and rill flow velocities. Laboratory experiments were conducted to compare the traditional dye tracer technique with this new thermal tracer technique by injecting a combined tracer (heated dye) into shallow flowing surface water. The leading edge tracer velocities estimated by means of infrared video and by the usual real imaging video were compared. The results show that thermal tracers can be used to estimate both overland and rill flow velocities, since measurements are similar to those resulting from using dye tracers. The main advantage of using thermography was the higher visibility of the leading edge of the injected tracer compared with the real image videos. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this study we present an infrared thermography technique that can be useful to detect soil surface microtopography in the presence of mulch. Laboratory test were carried out where the performance of the technique was evaluated in a surface with artificial rills and in a surface with microtopography created by water erosion, for different mulch cover conditions (bare soil, 2 and 4 t ha-1). Microtopography was detected applying heated water on the soil surface and recording the temperature with an infrared video camera. The technique allowed us to obtain 3D models of soil surface elevation both in the scenario with artificial rills and in the scenario with microtopography created by water erosion. With this technique it was possible to identify preferential flow paths and the different elements of microtopography, even in the presence of 2 t ha-1 of mulch covering the soil surface. In the scenario with cover density of 4 t ha-1, the detection of the thermal radiation emitted by the soil surface was severely affected, resulting in a decrease of the performance of the technique. [ABSTRACT FROM AUTHOR]

Abstract: Aqueous suspensions of graphite were shape stabilized by the additions of collagen and characterized as phase change materials for cold storage with enhanced thermal conductivity. Collagen addition stabilized the graphite suspensions in aqueous media without requirements for additional stabilizers or previous functionalization. Gelation at room temperatures prevented sedimentation of graphite particles. SEM of dried samples confirmed nearly random distribution of graphite particles. These gelled suspensions with enhanced thermal conductivity were tested for latent heat cold storage. The thermal response was retained upon repeated phase change cycles, and impedance spectroscopy was used to monitor these cycles. The response time upon phase change was somewhat longer than predicted by taking into account the values of thermal diffusivity and the estimated value of Stefan number, probably due to significant interfacial resistance to heat transfer, combined with discontinuities caused by volume expansion upon phase change. [Copyright &y& Elsevier]

Abstract: Objectives: To characterize and compare dynamic joint stiffness (DJS) of the ankle in the sagittal plane during natural cadence walking in both genders. Design: Observation, cross-sectional and matched pairs. Participants: Twenty-one males (mean age=27±4.2 years) and 18 females (mean age=22.9±4.1 years). Setting: Laboratory at the University de Trás-os-Montes and Alto Douro. The DJS of the ankle was assessed while participants performed barefoot walking at a natural cadence, was measured using a force platform (1000Hz), and synchronized with a high-speed camera (200Hz). Main outcome measures: DJS of the ankle in males and females was calculated in two sub-phases (the second and the fourth sub-phases) of the stance phase. The Wilcoxon non-parametric matched-pairs test and the Mann–Whitney U non-parametric test were used to analyse difference of DJS of the ankle within and between the groups with p⩽0.05 regarded as significant. Results: Male and female participants demonstrated significantly (p<0.005) less DJS during the second sub-phase. DJS was not significantly (p>0.063) different between females (0.0511Nm/kg/°) and males (0.0596Nm/kg/°) during the second sub-phase. DJS was significantly (p<0.001) higher in males (0.0844Nm/kg/°) than females (0.0691Nm/kg/°) during the fourth sub-phase. Conclusions: Gender-specific DJS characteristics demonstrated by females in this study may be used in preventative training programs designed to promote a greater ability to use contractile components to produce mechanical energy through the ankle. [Copyright &y& Elsevier]

This work presents a general three-dimensional multibody procedure for studying the human body motion with emphasis on the locomotion apparatus. The methodology includes a three-dimensional biomechanical model, data acquisition techniques and an inverse dynamics approach. The biomechanical model is based on a multibody formulation using natural coordinates and consists of 16 anatomical segments modeled by 33 rigid bodies for a total of 44 degrees-of-freedom. The action of the muscles is introduced in the equations of motion of the multibody model by means of driver actuators defined as kinematic constraints. By associating a Lagrange multiplier to each muscle actuator the muscle forces became coupled with the biomechanical model through the Jacobian matrix of the underlying multibody system. A Hill type muscle model is used to calculate individual muscle forces. The model for the muscle apparatus comprises 43 muscle groups for each leg, which use the full three-dimensional lines of action for these muscles in their geometric description. The problem of the redundancy of the forces on the musculoskeletal structure is solved by using inverse dynamics and static optimization methods. In the process of describing the methodology the benefits of modeling in natural coordinates are highlighted. The methodology developed is demonstrated through its application to a case of ballistic motion, represented by the take-off to an aerial trajectory in order to estimate the joint torques and the muscle force distribution in the supporting leg. The time characteristics of the resultant net torques at the basic joints of the supporting leg and the time-varying muscle force patterns are presented and discussed. The results obtained are explained in terms of their relevance to the activity under study. [ABSTRACT FROM AUTHOR]

Population pharmacokinetic (PK) models are widely used to inform drug development by pharmaceutical companies and facilitate drug evaluation by regulatory agencies. Developing a population PK model is a multi‐step, challenging, and time‐consuming process involving iterative manual model fitting and evaluation. A tool for fully automatic model development (AMD) of common population PK models is presented here. The AMD tool is implemented in Pharmpy, a versatile open‐source library for pharmacometrics. It consists of different modules responsible for developing the different components of population PK models, including the structural model, the inter‐individual variability (IIV) model, the inter‐occasional variability (IOV) model, the residual unexplained variability (RUV) model, the covariate model, and the allometry model. The AMD tool was evaluated using 10 real PK datasets involving the structural, IIV, and RUV modules in three sequences. The different sequences yielded generally consistent structural models; however, there were variations in the results of the IIV and RUV models. The final models of the AMD tool showed lower Bayesian Information Criterion (BIC) values and similar visual predictive check plots compared with the available published models, indicating reasonable quality, in addition to reasonable run time. A similar conclusion was also drawn in a simulation study. The developed AMD tool serves as a promising tool for fast and fully automatic population PK model building with the potential to facilitate the use of modeling and simulation in drug development. [ABSTRACT FROM AUTHOR]

The Pharmpy Automatic Model Development (AMD) tool automates the building of population pharmacokinetic (popPK) models by utilizing a systematic stepwise process. In this study, the performance of the AMD tool was assessed using simulated datasets. Ten true models mimicking classical popPK models were created. From each true model, dataset replicates were simulated assuming a typical phase I study design—single and multiple ascending doses with/without dichotomous food effect, with rich PK sampling. For every dataset replicate, the AMD tool automatically built an AMD model utilizing NONMEM for parameter estimation. The AMD models were compared to the true and reference models (true model fitted to simulated datasets) based on their model components, predicted population and individual secondary PK parameters (SP) (AUC0‐24, cmax, ctrough), and model quality metrics (e.g., model convergence, parameter relative standard errors (RSEs), Bayesian Information Criterion (BIC)). The models selected by the AMD tool closely resembled the true models, particularly in terms of distribution and elimination, although differences were observed in absorption and inter‐individual variability components. Bias associated with the derived SP was low. In general, discrepancies between AMD and true SP were also observed for reference models and therefore were attributed to the inherent stochasticity in simulations. In summary, the AMD tool was found to be a valuable asset in automating repetitive modeling tasks, yielding reliable PK models in the scenarios assessed. This tool has the potential to save time during early clinical drug development that can be invested in more complex modeling activities within model‐informed drug development. [ABSTRACT FROM AUTHOR]

Simple Summary: When a horse is diagnosed with a locomotor disorder, the veterinarian treats the specific injury to restore the horse to soundness. Even after the injury has healed, however, the horse may not be fully functional due to persistent limitations in movement or strength in specific areas of the body. As in people, rehabilitation seeks to optimize function and reduce any existing disability using a variety of methods including manual therapy, the use of physical and mechanical agents, and specialized exercise regimes. This study has reviewed the scientific literature with the goal of identifying which types of physical therapy have been described in horses over the past 20 years. The most frequently reported techniques were exercise, electrotherapy, and hydrotherapy but there are relatively few publications describing details of their use and outcomes in clinical cases. This study reviews the methodology and outcomes of rehabilitation in clinical cases. The results highlight the paucity of clinically-based reports on the practical applications of equine rehabilitation and physical therapy. Injuries to the locomotor system are a common problem in athletic horses. Veterinarians address these injuries using appropriate medical, surgical, and pharmacological treatments. During or after recovery from the initial injury, horses may be treated for functional locomotor deficits using specific rehabilitation techniques aimed at restoring full athletic performance. This study reviews the literature to identify which rehabilitative techniques have been used most frequently in horses over the past 20 years, the protocols that were used, and the outcomes of the treatments in naturally occurring injuries and diseases. Publications were identified using keyword selection (Equine Athlete OR Equine OR Horse) AND (Rehabilitation OR Physiotherapy OR Physical Therapy). After removing duplicates and screening papers for suitability, 49 manuscripts were included in the study. The majority of publications that met the inclusion criteria were narrative reviews (49%) in which the authors cited the relatively small number of published evidence-based studies supplemented by personal experience. Observational/descriptive studies were also popular (35%). Randomized control trials accounted for only 10%. The most frequently reported rehabilitation techniques were exercise, electrotherapy, and hydrotherapy. The findings highlight the need for further information regarding type of intervention, parameterization, and outcomes of equine rehabilitation in clinical practice. [ABSTRACT FROM AUTHOR]