Evaluating the usefulness of continuous leaf turgor pressure measurements for the assessment of Persimmon tree water status

Continuous plant water status monitoring is crucial in order to improve irrigation management. The noninvasive Yara ZIM-probe was assessed for detecting plant water stress in Persimmon trees (Diospyros kaki L.f.). The probe measures the pressure transfer function (Pp) through a patch of an intact leaf, which is inversely correlated with the turgor pressure. This technology was evaluated in two parallel experiments involving either distinct watering regimes or rootstocks with different drought tolerance [Diospyros lotus (L) and Diospyros virginiana (V)]. Concomitant measurements of midday stem water potential (Ψstem) and trunk diameter variations were taken throughout the experiments. Pp was highly correlated with Ψstem. Persimmon leaves exhibited the inversed Pp curve phenomena under water stress, which enabled the association of a particular range of Ψstem to each of the three leaf turgor states defined. Persimmon trees with no sign of initial or total inversion ensured Ψstem above −0.8 MPa, values considered of a well-watered Persimmon tree. Yara ZIM-probe readings as well as Ψstem and trunk diameter variation measurements pointed L as a more sensitive rootstock to drought than V. In conclusion, results showed that the Yara ZIM-probe can be used to continuously monitor water status in Persimmon trees although further research would be needed to ensure their feasibility for scheduling irrigation

Novel reaction force for ultra-relativistic dynamics of a classical point charge

The problem of the electromagnetic radiation of an accelerated charged particle is one of the most controversial issues in Physics since the beginning of the last century, representing one of the most popular unsolved problems of the Modern Physics. Different equations of motion have been proposed throughout history for a point charge including the electromagnetic radiation emitted, but all these expressions show some limitations. An equation based on the principle of conservation of energy is proposed in this work for the ultra-relativistic motion. Different examples are analyzed showing that the energy lost by the charge agrees with the Li\'enard formula. This proposed equation has been compared with the Landau-Lifshitz equation obtaining a good agreement in the range of application of the Landau-Lifshitz formula.Comment: 9 pages, 10 figure

Relativistic particle motion of a charge including the radiation reaction

The problem of the electromagnetic radiation of an accelerated charged particle is one of the most controversial issues in Physics since the beginning of the last century representing one of the most popular unsolved problems of the Modern Physics. Different equations of motion for a point charge including the electromagnetic radiation emitted have been proposed throughout history, but all these expressions show some limitations. An equation based on the principle of conservation of energy is proposed for the ultra-relativistic motion. Different examples are analyzed showing that the energy lost by the charge agrees with the relativistic generalization of the Larmor formula. This proposed equation has been compared with the Landau-Lifshitz equation obtaining a good agreement in the range of application of the Landau-Lifshitz formula. Finally, it is discussed a possible variation of the typical relativistic particle integrators (e.g. Boris, Vay or Higuera-Cary methods) in order to include the radiation reaction

Numerical study of dark current dynamics in a high-gradient backward travelling wave accelerating cavity using the electromagnetic simulation software CST studio.

High-Gradient accelerating cavities are one of the main research lines in the development of compact linear colliders. However, the operation of such cavities is currently limited by nonlinear effects that are intensified at high electric fields, such as dark currents and radiation emission or RF breakdowns. A new normal-conducting High-Gradient S-band Backward Travelling Wave accelerating cavity for medical application (v=0.38c) designed and constructed at Conseil Européen pour la Recherche Nucléaire (CERN) is being tested at Instituto de Física Corpuscular (IFIC) High Power RF Laboratory. The objective consists of studying its viability in the development of compact linear accelerators for hadrontherapy treatments in hospitals. Due to the high surface electric field in the cavity, electrons are emitted following Fowler- Nordheim equation, also known as dark currents. The emission and dynamic of these electrons are of fundamental importance on different phenomena such as RF Breakdowns or radiation dose emission. In this work, 3D electromagnetic numerical simulations have been performed using the computer simulation technology software CST Studio Suite. Then, the resulting EM field maps are used to study the emission and electron dynamics inside the cavity. The simulation results are compared with experimental data and first conclusions discussed

IKs Computational Modeling to Enforce the Investigation of D242N, a KV7.1 LQTS Mutation

A KCNQ1 mutation, D242N, was found in a pair of twins and characterized at the cellular level. To investigate whether and how the mutation causes the clinically observed lost adaptation to fast heart rate, we performed a computational study. Firstly, we identified a new I Ks model based on voltage clamp experimental data. Then we included this formulation in the human action potential model of O'Hara Rudy (ORd) and simulate d the effects of the mutation. We also included adrenergic stimulation to the action potential, since the basal adrenergic tone is likely to affect the influence of I Ks on QTc in vivo. Finally, we simulated the pseudo-ECG, taking into account the heterogeneity of the cardiac wall. At the basal rate (60bpm), the mutation had negligible effects for all cell types, whereas at the high rate (180bpm), with concomitant β-adrenergic stimulation (mimicking exercise conditions), the mutant AP failed to adapt its duration to the same extent as the wild-type AP (e.g. 281ms vs. 267ms in M cells), due to a smaller amount of I Ks current. Pseudo-ECG results show only a slight rate adaptation, and the simulated QTc was significantly prolonged from 387ms to 493ms, similar to experimental recordings

Study of the RF pulse heating phenomenon in high gradient accelerating devices by means of analytical approximations

The main objective of this work is to present a simple method, based on analytical expressions, for obtaining a quick approximation of the temperature rise due to the Joule effect inside the metallic walls of an RF accelerating device. This proposal relies on solving the 1D heat-transfer equation for a thick wall, where the heat sources inside the wall are the ohmic losses produced by the RF electromagnetic fields penetrating the metal with finite electrical conductivity. Furthermore, it is discussed how the theoretical expressions of this method can be applied to obtain an approximation to the temperature increase in realistic 3D RF accelerating structures, taking as an example the cavity of an RF electron gun. These theoretical results have been benchmarked with numerical simulations carried out with commercial finite-element method codes, finding good agreement among them

Photovoltaic Water Pumping: Comparison Between Direct and Lithium Battery Solutions

[EN] This work presents the conversion of a photovoltaic water pumping system (PVWPS) to its corresponding battery-based solution, while maintaining the components of the PVWPS facility and adding the power converter needed to manage the operation of a lithium-ion battery. A complete analysis of the direct PVWPS is performed based on the values obtained by the monitoring system developed for the installation. The efficiencies and performance ratios of the various elements of the facility are calculated, as well as other relevant factors (such as irradiance thresholds). The dependence of some variables on the solar resource is analyzed to model the system. A similar study is carried out in the battery-based solution and a comparative analysis of the two modes of operation is then performed to find which aspects could be improved in the battery-based solution to increase the pumping time and total daily pumped volume. The results presented demonstrate the benefits of including a battery (reduction in start/stop cycles and improved performance on cloudy days). Aspects that can be improved to make the battery-based solution more efficient and achieve better results are suggested.This work was supported in part by the Universitat Politecnica de Valencia (UPV-Program ADSIDEO-cooperation 2017-Project Characterization of sustainable systems for the pumping of water for human consumption in developing regions or refugee camps in Kenya through the implementation of isolated photovoltaic systems with new generation lithium-ion batteries), and in part by the International Organization for Migration under Contract entitled "Design, Assembly, Testing and Documenting Parameters of Solar and Ion-Lithium Energy Storage Equipment for Powering of Water Pumps under Laboratory Conditions'' from the Bureau for Humanitarian Assistance-USAID.Orts-Grau, S.; González Altozano, P.; Gimeno Sales, FJ.; Balbastre Peralta, I.; Martínez Márquez, CI.; Gasque Albalate, M.; Segui-Chilet, S. (2021). Photovoltaic Water Pumping: Comparison Between Direct and Lithium Battery Solutions. IEEE Access. 9:101147-101163. https://doi.org/10.1109/ACCESS.2021.3097246101147101163

Usefulness of the ZIM-probe technology for detecting water stress in clementine and persimmon trees

Further improvement on irrigation management requires continuous plant water status monitoring. The non-invasive ZIM-probe measures the pressure (Pp) transfer function through a patch of an intact leaf, which is inversely correlated with the turgor pressure. Data are sent wireless in real-Time by telemetry to an internet server via a mobile phone network where it is available to be analyzed. In this work, the detection of water stress by measuring relative changes in turgor pressure with the ZIM-probe was evaluated in clementine and persimmon trees. Ten trees of both species were equipped with two ZIM-probes each located at the east side of the canopy. The ZIM-probes were used over several months during which half of the trees were subjected to two drought cycles. Concomitant measurements of stem water potential (ψs) were taken at midday in both orchards during the drought periods. Additionally, determinations of ψs and stomatal conductance (gs) were also performed during 1-2 days at hourly intervals in the clementine and persimmon orchards, respectively, to study the existing relationship of these classical indicators with the leaf turgor pressure. Results showed that diurnal Pp values increased in non-irrigated clementine trees when water restrictions were imposed. Persimmon drought-stressed trees, on the other hand, showed different Pp curve shapes (half and complete inverse curve) depending on the level of stress reached by the trees. There was a tight correlation between the hourly spot measurements of ψs and gs with the probe data. Overall, results show that the ZIM-probe enables the detection of drought stress in clementine and persimmon trees. Nevertheless, different approaches for calculating the water stress level must be used in each of these species due to the higher tendency of persimmon leaves to the inversed Pp curve phenomena

Two-dimensional simulation of the electron transport in a photomultiplier tube

Photomultiplier tubes are widely used in experimental physics because they convert small light signals into a measurable electric current. Although their working principle is well known, it is very difficult to find simulations of the electron transport in these devices. For this reason, the electron transport in the Hamamatsu R13408-100 photomultiplier tube has been simulated in 2D. The software SUPERFISH is used for calculating the electrostatic fields and the Boris method for the effective electron dynamics. The secondary electron emission in the dynodes is implemented using an effective electron model and the modified Vaughan’s model. Some figures of merit for photomultiplier tubes (e.g. the gain, the electron transit time or the transit time spread) in function of the supply voltage and an external magnetic field have been studied obtaining a good qualitative accordance with the Hamamatsu datasheet. In further studies, we are going to compare our simulations with experimental measurements

Estudio de la marcha en pacientes tratados ortopédicamente de fractura unilateral del calcáneo

Veinticinco pacientes afectos de fractura unilateral desplazada articular de calcá- neo fueron tratados mediante inmovilización con yeso, siendo los resultados a los 6 años (rango: 3-10), excelentes en 5 pacientes, buenos en 4, regulares en 7 y malos en 9. De este grupo se excluyeron los afectos de patología local o general asociada, siendo útiles para el estudio de la marcha 12 pacientes a los que se les hizo deambular sobre plataformas dinamométricas para registrar la fuerza de reacción al suelo, demostrando una disminución de la fuerza vertical de apoyo y despegue (F1 y F3) y un aumento estadísticamente significativo del tiempo de apoyo total durante la marcha. Abogamos por la restitución anatómica del calcáneo como medio para mejorar la capacidad funcional del paciente.Twenty-five patients with unilateral displaced joint calcaneus fracture were treated by cast being the results after 6 years (range: 3-10), excellent in 5 patients, good in 4 patients, poor in 7 and bad in 9. We excluded for the study the patients with associated local or general pathology being useful for our study 12 patients. These patients walked on a dynamometric platform in order to analyse floor reaction forces, proving a diminuí ion of vertical support and takeoff forces (Fl and F2), and statistically significant a increase of total support phase during gait