3,228 research outputs found
Electrical technology students in vocational colleges: are they healthy mentally?
Distraction such as depression, anxiety, and stress in mental health problem can influence academic achievement to students, including vocational colleges’ students. Hence, the main purpose of this study was to determine the mental health profiles of Electrical Course students in Vocational Colleges. The difference in mental health level in terms of gender, hometown, and years of study were also be investigated. Besides, the level of mental health elements implementation by teachers in teaching and learning was also determined. This study was employed a survey method as research design that involved of 132 respondents from three vocational colleges in the southern zone. The respondents were selected using strata sampling technique. The instrument of this study was Malay version DASS-21 item inventory. This inventory measures three elements of mental health problem, namely depression, anxiety, and stress through 21 items. Questionnaires for level of mental health elements implementation by teachers in teaching and learning from student perception consists of 21 items. The collected data were analyzed using frequency, percentage, Spearman Rho test, Mann Whitney U test, and Kruskal Wallis test. The findings of this study showed that students' mental health level and the level of mental health elements implementation by teachers in teaching and learning were at the moderate level. The findings also found that there was a significant relationship between each element of mental health with students’ academic achievement level, as well as the level of mental health elements implementation by teachers in teaching and learning. In addition, the results also shows that there were no significant difference in the mental health level among the students from the aspects of gender, hometown, and years of study. In short, an intervention program needs to be implemented to overwhelm students’ mental health problems, because prevention was better than cure
Variable number of tandem repeat markers in the genome sequence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana (Musa spp)
ABSTRACT. We searched the genome of Mycosphaerella fijiensis for molecular markers that would allow population genetics analysis of this plant pathogen. M. fijiensis, the causal agent of banana leaf streak disease, also known as black Sigatoka, is the most devastating pathogen attacking bananas (Musa spp). Recently, the entire genome sequence of M. fijiensis became available. We screened this database for VNTR markers. Forty-two primer pairs were selected for validation, based on repeat type and length and the number of repeat units. Five VNTR markers showing multiple alleles were validated with a reference set of isolates from different parts of the world and a population from a banana plantation in Costa Rica. Polymorphism information content values varied from 0.6414 to 0.7544 for the reference set and from 0.0400 and 0.7373 for the population set. Eighty percent of the polymorphism information content values were above 0.60, indicating that the markers are highly informative. These markers allowed robust scoring of agarose gels and proved to be useful for variability and population genetics studies. In conclusion, the strategy we developed to identify and validate VNTR markers is an efficient means to incorporate markers that can be used for fungicide resistance management and to develop breeding strategies to control banana black leaf streak disease. This is the first report of VNTR-minisatellites from the M. fijiensis genome sequence. Key words: Molecular markers; VNTRs; Genetic diversity; Population genetics; Black Sigatok
Calorons, Nahm's equations on S^1 and bundles over P^1xP^1
The moduli space of solutions to Nahm's equations of rank (k,k+j) on the
circle, and hence, of SU(2) calorons of charge (k,j), is shown to be equivalent
to the moduli of holomorphic rank 2 bundles on P^1xP^1 trivialized at infinity
with c_2=k and equipped with a flag of degree j along P^1x{0}. An explicit
matrix description of these spaces is given by a monad constructio
The Woodpecker\u27s Beak: An Optimally Designed Structure/Material for Energy Absorption and Shock Mitigation
Woodpecker beaks have the ability to absorb shock energy without any damage to their body. In his book Origin of the Species Charles Darwin mentioned that the “woodpecker, with its feet, tail, beak, and tongue, so admirably adapted to catch insects under the bark of trees” in trying to explain how adaptation led to evolutionary changes in the woodpecker. Did the woodpecker with its beak, tongue, tail, and feet really adapt over long periods of evolutionary time or was it designed by its Creator to live in its particular environment and conditions. The analysis in this study shows the intense complexity of the woodpecker’s beak arguing for an engineering design by its Creator. In particular, this study focuses on the structure-property relationships of the woodpecker beak at multiple length scales. In particular, the woodpeckers’ beaks were examined through microscopy and nano/micro indentation to quantify the structure-property relationships with the perspective of mitigating shock waves. The beak of a woodpecker comprises three layers; exterior keratin layer (rhamphotheca) composed of overlapping scales, middle foam layer, and inner bony layer composed of mineral and collagen fiber. Indentation testing revealed that the hardness value of the inner layer is two to three times higher than that of the exterior layer. The overall design of the beak, tongue, and hyoid bone with their specific structure-property relationships in addition to the subsystem designed for shock mitigation appears to have been specifically designed for absorbing energy as they effectively dissipate energy as a whole. The perfection of the beak’s architectural complexity and fine systemization are highly indicative of it being designed by its Creator
SU(2) Calorons and Magnetic Monopoles
We investigate the self-dual Yang-Mills gauge configurations on when the gauge symmetry SU(2) is broken to U(1) by the Wilson loop. We
construct the explicit field configuration for a single instanton by the Nahm
method and show that an instanton is composed of two self-dual monopoles of
opposite magnetic charge. We normalize the moduli space metric of an instanton
and study various limits of the field configuration and its moduli space
metric.Comment: 17 pages, RevTex, 1 Figur
Modular Invariance and Characteristic Numbers
We show that a general miraculous cancellation formula, the divisibility of
certain characteristic numbers and some other topologiclal results are con-
sequences of the modular invariance of elliptic operators on loop spaces.
Previously we have shown that modular invariance also implies the rigidity of
many elliptic operators on loop spaces.Comment: 14 page
Geological Effect on GPR System Due to Soil Properties in Malaysia
This paper present the measurement of dielectric properties of soil in Malaysia in three differences condition which are normal condition (ambience), heated (up to 50 OC) and wet condition (10 % water content). Eight (8) samples of soil have been collected in the local region and was measured in the frequency range from 0.5 GHz to 3.5 GHz for Ground Penetrating Radar (GPR) applications. The measurement of the dielectric properties has been conducted using Agilent high temperature probe (Model) integrated with Performance Network Analyzer (PNA E8362B). The uncertainties in measurement process, especially dealing with measurement data have been considered in order to eliminate the probability of error during the measurement. The measured result for permittivity and loss factor of the measured samples are tabulated in graphs and the analysis of the measured data are discussed in this paper
Dual-acting stapled peptides target both HIV-1 entry and assembly
Background:
Previously, we reported the conversion of the 12-mer linear and cell-impermeable peptide CAI to a cell-penetrating peptide NYAD-1 by using an i,i + 4 hydrocarbon stapling technique and confirmed its binding to the C-terminal domain (CTD) of the HIV-1 capsid (CA) protein with an improved affinity (Kd ~ 1 μM) compared to CAI (Kd ~ 15 μM). NYAD-1 disrupts the formation of both immature- and mature-like virus particles in in vitro and cell-based assembly assays. In addition, it displays potent anti-HIV-1 activity in cell culture against a range of laboratory-adapted and primary HIV-1 isolates.<p></p>
Results:
In this report, we expanded the study to i,i + 7 hydrocarbon-stapled peptides to delineate their mechanism of action and antiviral activity. We identified three potent inhibitors, NYAD-36, -66 and -67, which showed strong binding to CA in NMR and isothermal titration calorimetry (ITC) studies and disrupted the formation of mature-like particles. They showed typical α-helical structures and penetrated cells; however, the cell penetration was not as efficient as observed with the i,i + 4 peptides. Unlike NYAD-1, the i,i + 7 peptides did not have any effect on virus release; however, they impaired Gag precursor processing. HIV-1 particles produced in the presence of these peptides displayed impaired infectivity. Consistent with an effect on virus entry, selection for viral resistance led to the emergence of two mutations in the gp120 subunit of the viral envelope (Env) glycoprotein, V120Q and A327P, located in the conserved region 1 (C1) and the base of the V3 loop, respectively.<p></p>
Conclusion:
The i,i + 7 stapled peptides derived from CAI unexpectedly target both CA and the V3 loop of gp120. This dual-targeted activity is dependent on their ability to penetrate cells as well as their net charge. This mechanistic revelation will be useful in further modifying these peptides as potent anti-HIV-1 agents.<p></p>
Contact resistance in graphene-based devices
We report a systematic study of the contact resistance present at the
interface between a metal (Ti) and graphene layers of different, known
thickness. By comparing devices fabricated on 11 graphene flakes we demonstrate
that the contact resistance is quantitatively the same for single-, bi-, and
tri-layer graphene (), and is in all cases
independent of gate voltage and temperature. We argue that the observed
behavior is due to charge transfer from the metal, causing the Fermi level in
the graphene region under the contacts to shift far away from the charge
neutrality point
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