Strength-frequency curve for micromagnetic neurostimulation through excitatory postsynaptic potentials (EPSPs) on rat hippocampal neurons and numerical modeling of magnetic microcoil (μcoil)

Objective: The objective of this study was to measure the effect of micromagnetic stimulation (μMS) on hippocampal neurons, by using single microcoil (μcoil) prototype, Magnetic Pen (MagPen). MagPen will be used to stimulate the CA3 magnetically and excitatory post synaptic potential (EPSP) measurements will be made from the CA1. The threshold for μMS as a function of stimulation frequency of the current driving the µcoil will be demonstrated. Finally, the optimal stimulation frequency of the current driving the μcoil to minimize power will be estimated. Approach: A biocompatible prototype, MagPen was built, and customized such that it is easy to adjust the orientation of the μcoil over the hippocampal tissue in an in vitro setting. Finite element modeling (FEM) of the μcoil was performed to estimate the spatial profiles of the magnetic flux density (in T) and the induced electric fields (in V/m). The induced electric field profiles generated at different values of current applied to the µcoil whether can elicit a neuron response was validated by numerical modeling. The modeling settings were replicated in experiments on rat hippocampal neurons. Main results: The preferred orientation of MagPen over the Schaffer Collateral fibers was demonstrated such that they elicit a neuron response. The recorded EPSPs from CA1 due to μMS at CA3 were validated by applying tetrodotoxin (TTX). Finally, it was interpreted through numerical analysis that increasing frequency of the current driving the μcoil, led to a decrease in the current amplitude threshold for μMS. Significance: This work reports that μMS can be used to evoke population EPSPs in the CA1 of hippocampus. It demonstrates the strength-frequency curve for µMS and its unique features related to orientation dependence of the µcoils, spatial selectivity and distance dependence. Finally, the challenges related to µMS experiments were studied including ways to overcome them.

Analisis Hidrologi untuk Perencanaan Sistem Polder di DKI Jakarta

The application of the polder system for flood control in DKI Jakarta has become a must for coastal areas, especially with the construction of sea dikes along the coast of Jakarta as a solution to anticipate tidal flooding. One thing to consider when using a polder system in flood control is how much pump capacity and reservoir are needed. To answer this quetions, a hydrological analysis has been carried out with several method approaches, starting from determining the rainfall design in the form of a depth duration frequency curve in 1 hour to 48 hours, and then applied area reduction factor (ARF) to corrected rainfall design. Natural Resources Conservation Service (NRCS) method are uses to calculated runoff or effective rainfall and then with the unit hydrograph by time area method to produce a runoff hydrograph. Based on this approach, the Sentiong Polder plan has been carried out with the result that the required pump capacity for a 25-year return period is 32 m3/s and 50 m3/s for a 100-year return period with a storage capacity used of 1,507,500 m3. If you want to reduce the pump capacity, it is necessary to increase the storage capacity.

Sudden Commencements and Impulses in Kodaikanal magnetograms -their hourly frequency

The diurnal variation in the frequencies of sudden commencements (SCs) and sudden impulses (SIs) at Kodaikanal (10.2°N, 77.5°E) is analysed from the data for the period 1949-1957.The hourly frequency curve of SCs and SIs (combined) has little resemblance to the curve obtained by Newton from his analysis of Greenwich-Abinger record. The results of harmonic analysis show a nearly semi-diurnal trend the distribution of storm sudden commencements (SSCs); this, however, is small. The hourly frequencies of SIS show s significant diurnal variation with an afternoon maximum and a forenoon maximum and a secondary minimum around 18h local time and a secondary maximum around 08h. These results are also compared with those obtained by Ferraro Parkinson and Unthank.

The Variable Frequency Conductivity of Geopolymers during the Long Agieng Period

The variable frequency conductivity was applied to characterize the process of solidification of geopolymers based on fly ash with sand additives. XRD qualitative and quantitative analysis, porosity measurements, and sorption analysis of specific surface area were performed. The conductivity was correlated with porosity and specific surface area of geopolymer concretes. Both values of conductivity, real and imaginary parts, decreased during polymerization processing time. Characteristic maximum on graphs describing susceptance vs. frequency curve was observed. The frequency of this maximum depends on time of polymerization and ageing, and can also indicate porosity of material. Low-porous geopolymer concrete shows both low-conductivity values, and susceptance maximum frequency peak occurs more in the higher frequencies than in high-porous materials.

Stochastic Hybrid Event Based and Continuous Approach to Derive Flood Frequency Curve

This study proposes a methodology that combines the advantages of the event-based and continuous models, for the derivation of the maximum flow and maximum hydrograph volume frequency curves, by combining a stochastic continuous weather generator (the advanced weather generator, abbreviated as AWE-GEN) with a fully distributed physically based hydrological model (the TIN-based real-time integrated basin simulator, abbreviated as tRIBS) that runs both event-based and continuous simulation. The methodology is applied to Peacheater Creek, a 64 km2 basin located in Oklahoma, United States. First, a continuous set of 5000 years’ hourly weather forcing series is generated using the stochastic weather generator AWE-GEN. Second, a hydrological continuous simulation of 50 years of the climate series is generated with the hydrological model tRIBS. Simultaneously, the separation of storm events is performed by applying the exponential method to the 5000- and 50-years climate series. From the continuous simulation of 50 years, the mean soil moisture in the top 10 cm (MSM10) of the soil layer of the basin at an hourly time step is extracted. Afterwards, from the times series of hourly MSM10, the values associated to all the storm events within the 50 years of hourly weather series are extracted. Therefore, each storm event has an initial soil moisture value associated (MSM10Event). Thus, the probability distribution of MSM10Event for each month of the year is obtained. Third, the five major events of each of the 5000 years in terms of total depth are simulated in an event-based framework in tRIBS, assigning an initial moisture state value for the basin using a Monte Carlo framework. Finally, the maximum annual hydrographs are obtained in terms of maximum peak-flow and volume, and the associated frequency curves are derived. To validate the method, the results obtained by the hybrid method are compared to those obtained by deriving the flood frequency curves from the continuous simulation of 5000 years, analyzing the maximum annual peak-flow and maximum annual volume, and the dependence between the peak-flow and volume. Independence between rainfall events and prior hydrological soil moisture conditions has been proved. The proposed hybrid method can reproduce the univariate flood frequency curves with a good agreement to those obtained by the continuous simulation. The maximum annual peak-flow frequency curve is obtained with a Nash–Sutcliffe coefficient of 0.98, whereas the maximum annual volume frequency curve is obtained with a Nash–Sutcliffe value of 0.97. The proposed hybrid method permits to generate hydrological forcing by using a fully distributed physically based model but reducing the computation times on the order from months to hours.

Design of edges in contour and half moons from edaphoclimatic parameters, for the endorrheic basin of lagunas de tajzara - ramsar site 1030

The collection of water is proposed from the design of contour borders and half moons, green infrastructure measures, to reduce surface runoff and increase the availability of water for vegetation. The contour and crescent ridges have land ridges with a trapezoidal section, which follow the contour lines, to compartmentalize the slope into smaller hydrological units, the ends of which are located on contour lines. With the data of maximum rainfall every 24 hours and parameters of Gumbel's Law modified, the equations of maximum daily rainfall height (hdT), rainfall height for a duration ´´t´´ (htT), and the Intensity Duration Frequency curve (ItT), for a duration of t <2h. Then considering the values of basic infiltration, vegetation cover, soil type and hydrological condition, the curve numbers were determined for different soil moisture conditions, later the separation length (L) between the Half Moons, and the borders was calculated. in contour, which were designed by means of 10 configurations between diameter and height, for the two infrastructures, being in Copacabana Valle, the greatest separation distance.

Insular Pharmacopoeias: Ethnobotanical Characteristics of Medicinal Plants Used on the Adriatic Islands

The Adriatic islands in Croatia, usually divided into two archipelagos – the Kvarner and Dalmatian islands – is one of the largest groups of islands in Europe. Over 40 islands are still inhabited. Unfortunately the traditional use of medicinal plants was never properly documented there. Our data comes from 343 interviews carried out in 36 islands, including the 15 largest islands of the archipelago. The medicinal plants are mainly used to make herbal infusions or decoctions, occasionally medicinal liqueurs, syrups, compresses, or juices squeezed out of raw plants. We recorded the use of 146 taxa, among them 131 with at least one medicinal purpose and 15 only for tea. The frequency curve of use is relatively steep – several plants are used very frequently and most are reported only by one or two informants, which can be explained both by the large geographical spread of the area, and even more so by the devolution of local knowledge and disappearance of gathering practices due to specialization in tourism, modernization and depopulation. Most of the gathered plants already occur in ancient and medieval herbals and are a part of the pan-Mediterranean pharmacopoeia.