1,449 research outputs found
Asthenopia Pada Pekerja Wanita Di Call Centre-x
. Nowdays, computers have been used widely in every kind of occupation. One of the health problems of the computer using is eyestrain or asthenopia. Some experts have tried to correlate the exposure of Video Display Terminal (VDT) with the occurrence of asthenopia but until present there is no database about the prevelance of computer operators found they more easily become asthenopic. The complain of asthenopia itself is subjective and varies in every individual and therefore one measureable objective value is needed to determine the occurrence of the asthenopia case itself.The design of the study was using "pre and post test", it involved 72 subjects in "X"-call centre and using photostress test to measure objectively the occurrence ofasthenopia by measuring the increasing of Macular Recovery Time (MKT) before and after working.The average shift of MKT was about 2.98 ± 3.57 second within 68.1 % of thesubjects, which were evaluated after 4-hour working time with their VDT. The distance between the eyes to VDT and the satisfaction with the working shift arrangement had significant correlation with the occurrence of asthenopia. There was significant correlation between subjective complaints such as pain within the area around the eyes,headache and dry eyes due to increasing of the MR
First isolation and identification of Vibrio vulnificus (biotype 2) from cultured beluga, huso huso in Iran
By decreasing sturgeon stocks in the Caspian Sea, rearing different sturgeon species especially Huso huso was increased in Iran. Under stress conditions the sturgeon can easily be infected by several opportunistic pathogens. In June 2011, mortality happened in 25 - 28°C water temperature, in one of the most important cultured sturgeon farms in Mazandaran province, north of Iran. The mortality rate was 15%. The first clinical signs in moribund fish were lethargy and anorexia. A total of 20 moribund fish was transferred to a central laboratory for more bacteriological examination. Clinical signs including several deep ulcers on body surface, around the head, under operculum, ulcers at the base of the pectoral fins, hemorrhage around the anus, operculum, and pale gills were observed in moribund fish. The main internal signs were hepatomegaly and splenomegaly, liquid accumulation in the intestine and diffuse visceral hemorrhage. The results of morphology and microscopic characterizations and also biochemical tests indicated that Vibrio vulnificus (biotype 2) was the etiological agent of mortality in infected fish. This study was the first report of V. vulnificus in cultured H. huso in Iran
Konversi Lahan Pertanian Produktif Akibat Pertumbuhan Lahan Terbangun Di Kecamatan Kota Sumenep
Penelitian tentang konversi lahan pertanian produktif akibat pertumbuhan lahan terbangun di Kota Sumenep bertujuan untuk mengetahui karakteristik Perubahan tutupan lahan, faktor-faktor yang menyebabkan konversi lahan pertanian produktif, faktor-faktor yang menyebabkan petani menjual lahannya, serta dampak konversi lahan pertanian produktif terhadap nilai ekonomi produksi tanaman pangan. Metode penelitian yang digunakan dalam penelitian ini adalah metode kuantitatif dan kualitatif dengan alat analisis berupa analisis tutupan lahan, analisis Perubahan tutupan lahan, analisis faktor dan analisis produktifitas yang hilang. Berdasarkan hasil penelitian diketahui bahwa terdapat hubungan antara pertumbuhan luas lahan terbangun dan penurunan luas lahan tidak terbangun. Semakin tinggi pertumbuhan luas lahan terbangun, maka semakin menyusut luas lahan tidak terbangun yang tersedia. Dari data klasifikasi tutupan lahan terlihat bahwa lahan terbangun mengalami peningkatan luas sekitar 9,15 Ha setiap tahunnya dan sebaliknya lahan tidak terbangun mengalami penurunan luas sekitar 9,15 Ha setiap tahunnya. Dari hasil analisis faktor-faktor yang menyebabkan konversi lahan diperoleh enam variabel yang berpengaruh, yaitu lokasi lahan, saluran irigasi, himpitan ekonomi, pertambahan penduduk, kebutuhan tempat tinggal. Sedangkan hasil dari analisis faktor-faktor yang menyebabkan petani menjual lahannya diperoleh enam variabel yang berpengaruh, yaitu luas lahan, pengaruh pihak swasta, generasi muda, tuntutan kebutuhan hidup, tanggungan keluarga, serta kebijakan dan peraturan pemerintah. Untuk dampak konversi lahan terhadap nilai ekonomi produksi tanaman pangan diketahui bahwa selama kurun waktu 5 tahun (2010-2014) diperkirakan telah terjadi Perubahan guna lahan pertanian produktif menjadi lahan non pertanian dan berdampak terhadap hilangnya penerimaan dari USAha tani padi sebesar Rp 799.839.797
A Fabry-Perot interferometer with quantum mirrors: nonlinear light transport and rectification
Optical transport represents a natural route towards fast communications, and
it is currently used in large scale data transfer. The progressive
miniaturization of devices for information processing calls for the microscopic
tailoring of light transport and confinement at length scales appropriate for
the upcoming technologies. With this goal in mind, we present a theoretical
analysis of a one-dimensional Fabry-Perot interferometer built with two highly
saturable nonlinear mirrors: a pair of two-level systems. Our approach captures
non-linear and non-reciprocal effects of light transport that were not reported
previously. Remarkably, we show that such an elementary device can operate as a
microscopic integrated optical rectifier
Antimicrobial and antioxidant effects of nisin Z and sodium benzoate in vacuum packed Caspian kutum (Rutilus frisii) fillet stored at 4°C
This study was done to evaluate the antimicrobial and antioxidant effects of nisin Z (0.02 %) and sodium benzoate (1.5 and 2.5 %) in vacuum packed Caspian Kutum (Rutilus frisii) fillet stored at 4°C. Microbial changes [aerobic plate counts (APC), psychrotrophic counts (PTC) and lactic acid bacteria] and chemical indices [peroxide value and total volatile basic nitrogen (TVB-N)] were determined in days 0, 4, 8, 12 and 16. Results showed that PV and TVB-N in control samples (the sample dipped in prechilled distilled water) were deteriorated after 12 days compared to preserved samples which were acceptable after 16 days. Microbial tests indicated that control samples contained APC and PTC bacteria in day 16 more than standard limit, whereas treatment samples were in the acceptable range. In case of lactic acid bacteria, after 16 days, all samples were in the acceptable range. Results of chemical and microbial analysis showed that simultaneous use of nisin Z and sodium benzoate could increase the shelf life of vacuum packed R. frisii
A nanoflare model for active region radiance: application of artificial neural networks
Context. Nanoflares are small impulsive bursts of energy that blend with and
possibly make up much of the solar background emission. Determining their
frequency and energy input is central to understanding the heating of the solar
corona. One method is to extrapolate the energy frequency distribution of
larger individually observed flares to lower energies. Only if the power law
exponent is greater than 2, is it considered possible that nanoflares
contribute significantly to the energy input.
Aims. Time sequences of ultraviolet line radiances observed in the corona of
an active region are modelled with the aim of determining the power law
exponent of the nanoflare energy distribution.
Methods. A simple nanoflare model based on three key parameters (the flare
rate, the flare duration time, and the power law exponent of the flare energy
frequency distribution) is used to simulate emission line radiances from the
ions Fe XIX, Ca XIII, and Si iii, observed by SUMER in the corona of an active
region as it rotates around the east limb of the Sun. Light curve pattern
recognition by an Artificial Neural Network (ANN) scheme is used to determine
the values.
Results. The power law exponents, alpha 2.8, 2.8, and 2.6 for Fe XIX, Ca
XIII, and Si iii respectively.
Conclusions. The light curve simulations imply a power law exponent greater
than the critical value of 2 for all ion species. This implies that if the
energy of flare-like events is extrapolated to low energies, nanoflares could
provide a significant contribution to the heating of active region coronae.Comment: 4 pages, 5 figure
Relativistic total cross section and angular distribution for Rayleigh scattering by atomic hydrogen
We study the total cross section and angular distribution in Rayleigh
scattering by hydrogen atom in the ground state, within the framework of Dirac
relativistic equation and second-order perturbation theory. The relativistic
states used for the calculations are obtained by making use of the finite basis
set method and expressed in terms of B-splines and B-polynomials. We pay
particular attention to the effects that arise from higher (non-dipole) terms
in the expansion of the electron-photon interaction. It is shown that the
angular distribution of scattered photons, while it is symmetric with respect
to the scattering angle =90 within the electric dipole
approximation, becomes asymmetric when higher multipoles are taken into
account. The analytical expression of the angular distribution is parametrized
in terms of Legendre polynomials. Detailed calculations are performed for
photons in the energy range 0.5 to 10 keV. When possible, results are compared
with previous calculations.Comment: 8 pages, 5 figure
Relativistic polarization analysis of Rayleigh scattering by atomic hydrogen
A relativistic analysis of the polarization properties of light elastically
scattered by atomic hydrogen is performed, based on the Dirac equation and
second order perturbation theory. The relativistic atomic states used for the
calculations are obtained by making use of the finite basis set method and
expressed in terms of splines and polynomials. We introduce two
experimental scenarios in which the light is circularly and linearly polarized,
respectively. For each of these scenarios, the polarization-dependent angular
distribution and the degrees of circular and linear polarization of the
scattered light are investigated as a function of scattering angle and photon
energy. Analytical expressions are derived for the polarization-dependent
angular distribution which can be used for scattering by both hydrogenic as
well as many-electron systems. Detailed computations are performed for Rayleigh
scattering by atomic hydrogen within the incident photon energy range 0.5 to 10
keV. Particular attention is paid to the effects that arise from higher
(nondipole) terms in the expansion of the electron-photon interaction.Comment: 8 pages, 5 figure
Body-assisted van der Waals interaction between two atoms
Using fourth-order perturbation theory, a general formula for the van der
Waals potential of two neutral, unpolarized, ground-state atoms in the presence
of an arbitrary arrangement of dispersing and absorbing magnetodielectric
bodies is derived. The theory is applied to two atoms in bulk material and in
front of a planar multilayer system, with special emphasis on the cases of a
perfectly reflecting plate and a semi-infinite half space. It is demonstrated
that the enhancement and reduction of the two-atom interaction due to the
presence of a perfectly reflecting plate can be understood, at least in the
nonretarded limit, by using the method of image charges. For the semi-infinite
half space, both analytical and numerical results are presented.Comment: 17 pages, 9 figure
- …
