Effect of some biocontrol agents against root-knot nematode (Meloidogyne incognita race2)

Culture filtrate of four rhizospheric fungi and four biocontrol agents were studied in vitro for their efficacy against Meloidogyne incognita race 2. The per cent mortality and egg hatching inhibition was proportional to the concentration of culture filtrate and the duration of exposure period. Culture filtrates of Trichoderma viride, Trichoderma harzianum, Trichoderma sp., Fusarium sp., Penicillium sp. and Aspergillus sp. significantly induced inhibition of egg hatching and mortality of Meloidogyne incognita race 2.The highest percentage of inhibition of egg hatching and juvenile mortality was recorded in Trichoderma harzianum followed by Trichoderma viride and Trichoderma sp

Psychosocial learning environments: EFL learners’ voices during a pandemic

The aim of this study was to investigate university students’ psychosocial apperceptions between face-to-face and emergency remote learning environments they experienced in the same academic term during the 2019-nCoV (coronavirus) pandemic of 2020. Utilizing a mixed methods study design, our investigation involved quantitative data collection with the DELES-TR instrument, followed by online focus group interviews with questions derived from the survey results to gain a deeper understanding of students’ perspectives of both educational environments. English as a Foreign Language students (N=687) from Çanakkale Onsekiz Mart University, Turkey participated in the study. The results indicated that students preferred the face-to-face environment over emergency remote learning due to difficulty in communication with instructors and peers and requiring students to take an active, responsible, and accountable role in their own learning in the remote learning environment

Pulsed x-rays dose measurements from a hundred joules plasma focus device

Indexación: Scopus.Present work is aimed to perform dosimetric measurements to characterize dosis obtained from pulsed x-rays emitted from a hundred joules plasma focus device PF-400J using thermoluminescent dosimeters (TLD-100). Two dosimeter arrays (containing 21 dosimeters in each) were used. One of the arrays was kept inside the PF-400J vacuum chamber and other outside the vacuum chamber, simultaneously. It was found that dosis obtained from the inside array (∼200.7 mGy) were hundred times larger than the outside array (∼1.1 mGy) for hundred pulses of x-rays. Later, the vacuum window of PF-400J, which was made of 1 mm aluminum, was replaced by a plastic window and a similar dosimeter array was kept outside the chamber over the plastic window. With this arrangement, the obtained doses (100 pulses of x-rays) were of the same order of magnitude (∼106 mGy) as it was inside the vacuum chamber. Later, a lead piece was inserted inside the hollow anode of PF-400J, which increased dose (∼250 mGy) per hundred pulses of x-ray outside the vacuum chamber using plastic vacuum window. Our results suggest that PF-400J could be a useful device to study low dose pulsed radiation effects on cancer cell lines in in vitro experiments. © Published under licence by IOP Publishing Ltd.The work is supported by grant ACT-1115, CONICYT, Chile.https://iopscience.iop.org/article/10.1088/1742-6596/1043/1/01204

Analysis of Deterioration in a Plasma Focus Device

Indexación: Scopus.The Plasma Focus (PF) is a kind of dense transient plasmas in with high-pulsed voltage. To produce devices for eld application it is necessary to obtain PF equipment able to operate for a long period of time. Thus, a reliability analysis is indispensable. In this work a reliability analysis program for plasma focus devices is presented. The program considers a criticality analysis using Failure Modes and Effects Criticality Analysis (FMECA) to identify the most important failure modes of the system. Said failure modes are studied operating the Plasma Focus for many cycles, obtaining from them the characteristic curves of V(t) and İ(t). Feature Extraction (FE) techniques are applied to obtain a list of parameters that correlate to the degrading process. Furthermore, Machine Learning tools are used to learn from the obtained data, linking the changes in these parameters during its life cycle to the decay of the system in hope for future implementation of a predictive maintenance system and a reference for data analysis and prediction in PFs. The study was applied to a portable plasma focus device operated at 2 joules of stored energy. © Published under licence by IOP Publishing Ltd.The work is supported by IAEA CRP contract 20370 and by grant ACT-1115, CONICYT, Chile.https://iopscience.iop.org/article/10.1088/1742-6596/1043/1/01204

Impact of pruning on growth, yield and quality of mango cv. Dashehari

An experiment was carried out to study the impact of pruning on growth, yield and quality of mango cv. Dashehari. Ten treatments consisted of heading back of terminal shoots at two different levels viz., M1: 10 cm & M2: 20 cm, with two level of frequency i.e., F1: annually & F2: biennially and at two different timings i.e., T1: immediately after fruit harvest (June-July) & T2: during rest period before the emergence of new growth (floral and vegetative) including control as M0F0T0 with and without Paclobutazol (PBZ), were imposed on the trees. The trial was laid out in Randomized block design replicated thrice and single tree served as treatment unit. On the basis of 6 years (2009-2014) pooled data, it was observed that the vigorous growth in terms of tree height (4.56 m), trunk circumference (43.56 cm) and tree spread (3.03 m) were observed in the trees under control (M0F0T0 without PBZ), whereas the trees which were pruned annually by heading back of 20 cm of terminal shoots during rest period before emergence of new growth along with paclabutrazol application (M2F1T2) showed less growth in terms of tree height (3.30 m) and spread (2.21 m). The annual pruning of tree by heading back of 10 cm of terminal shoots immediately after fruit harvest along with paclobutrazol application (M1F1T1) proved effective for increasing the number of fruits per tree (51.31), yield (9.09 kg/tree and 15.14 t/ha), B: C ratio (4.04), maintaining fruit quality and for having the appropriate dwarfing effect on the tree

Hundred joules plasma focus device as a potential pulsed source for in vitro cancer cell irradiation

Indexación: Web of Science; Scopus.Plasma focus devices may arise as useful source to perform experiments aimed to study the effects of pulsed radiation on human cells in vitro. In the present work, a table top hundred joules plasma focus device, namely "PF-400J", was adapted to irradiate colorectal cancer cell line, DLD-1. For pulsed x-rays, the doses (energy absorbed per unit mass, measured in Gy) were measured using thermoluminescence detectors (TLD-100 dosimeters). The neutron fluence and the average energy were used to estimate the pulsed neutron doses. Fifty pulses of x-rays (0.12 Gy) and fifty pulses of neutrons (3.5 μGy) were used to irradiate the cancer cells. Irradiation-induced DNA damage and cell death were assessed at different time points after irradiation. Cell death was observed using pulsed neutron irradiation, at ultralow doses. Our results indicate that the PF-400J can be used for in vitro assessment of the effect of pulsed radiation in cancer cell research.http://recursosbiblioteca.unab.cl:2296/doi/pdf/10.1063/1.499465

Thermal instability of an expanding dusty plasma with equilibrium cooling

We present an analysis of radiation induced instabilities in an expanding plasma with considerable presence of dust particles and equilibrium cooling. We have shown that the equilibrium expansion and cooling destabilize the radiation condensation modes and the presence of dust particles enhances this effect. We have examined our results in the context of ionized, dusty-plasma environments such as those found in planetary nebulae (PNe). We show that due to the non-static equilibrium and finite equilibrium cooling, small-scale localized structures formed out of thermal instability, become transient, which agrees with the observational results. The dust-charge fluctuation is found to heavily suppress these instabilities, though in view of non-availability of convincing experimental data, a definitive conclusion could not be made.Comment: 23 pages, 14 figure

A test of the standard dark matter density evolution law using galaxy clusters and cosmic chronometers

In this letter, we implement a test of the standard law for the dark matter density evolution. For this purpose, only a flat universe and the validity of the FRW metric are assumed. A deformed dark matter density evolution law is considered, given by $\rho_c(z) \propto (1+z)^{3+\epsilon}$, and constraints on $\epsilon$ are obtained by using galaxy cluster gas mass fractions, and cosmic chronometers measurements. We find that $\epsilon =0$ within 2$\sigma$ c.l., in full agreement with other recent analyses.Comment: 6 Pages and 3 figure

Temperature dependence of the resistance of metallic nanowires (diameter ≥\geq 15 nm): Applicability of Bloch-Gr\"{u}neisen theorem

We have measured the resistances (and resistivities) of Ag and Cu nanowires of diameters ranging from 15nm to 200nm in the temperature range 4.2K-300K with the specific aim to assess the applicability of the Bloch-Gr\"{u}neisen formula for electron phonon resistivity in these nanowires. The wires were grown within polymeric templates by electrodeposition. We find that in all the samples the resistance reaches a residual value at T=4.2K and the temperature dependence of resistance can be fitted to the Bloch-Gr\"{u}neisen formula in the entire temperature range with a well defined transport Debye temperature ($\Theta_{R}$). The value of Debye temperature obtained from the fits lie within 8% of the bulk value for Ag wires of diameter 15nm while for Cu nanowires of the same diameter the Debye temperature is significantly lesser than the bulk value. The electron-phonon coupling constants (measured by $\alpha_{el-ph}$ or $\alpha_{R}$) in the nanowires were found to have the same value as that of the bulk. The resistivities of the wires were seen to increase as the wire diameter was decreased. This increase in the resistivity of the wires may be attributed to surface scattering of conduction electrons. The specularity p was estimated to be about 0.5. The observed results allow us to obtain the resistivities exactly from the resistance and gives us a method of obtaining the exact numbers of wires within the measured array (grown within the template).Comment: 9 pages, 10 figure