Ionization effects due to solar flare on terrestrial ionosphere

Sudden frequency deviation ionospheric disturbances related to the flares of May 18 and 19, 1973 were observed from the NASA/MSFC high frequency Doppler sounder array system in Huntsville, Alabama. The results are compared with those observed at Table Mountain near Boulder, Colorado and at the University of Hawaii

Valley filter in strain engineered graphene

We propose a simple, yet highly efficient and robust device for producing valley polarized current in graphene. The device comprises of two distinct components; a region of uniform uniaxial strain, adjacent to an out-of-plane magnetic barrier configuration formed by patterned ferromagnetic gates. We show that when the amount of strain, magnetic field strength, and Fermi level are properly tuned, the output current can be made to consist of only a single valley contribution. Perfect valley filtering is achievable within experimentally accessible parameters.Comment: 4 pages, 3 figures; minor corrections, updated Figs. 2 and 3, added reference

Differential pulse polarography and voltammetry with an automated microprocessor-based polarograph and a static mercury drop electrode

Differential pulse polarography using an automated, microprocessor- based polarographic analyzer equipped with a static mercury drop electrode has been evaluated with respect to pulse amplitude, scan rate, drop time (t), and drop area. Variation of peak current, z"p' with drop area and t - Y2, with some pulse amplitudes agree reasonably well with theory. However, dependence of and E or i scan rate and on pulse amplitude at very large and very small amplitudes was found to devide fron i theory. Similar trends were also found for anodic stripping voltammetry when differential pulse stripping was used. The precision attainable by both techniques was good. Copper peaks demonstrated good precision only when copper was plated out individually during anodic stripping voltammetry

Risk Quotient of Airborne Paraquat Exposure Among Workers in Palm Oil Plantation

Paraquat is the herbicide widely used at palm oil plantations, although usage it in some countries has been banned and restricted. Paraquat spraying was not appropriate procedure could be polluted the environment and lead to health disorders workers. Paraquat could enter the body through inhalation, dermal and ingestion, one of frequent routes through inhalation during spraying weeds in plantation areas. This study aimed was to analyze potential inhalation dose and Risk Quotient to workers at palm oil plantation. This research was a descriptive study with cross sectional design and analysis of environmental health risk methods. Airborne Paraquat residue was collected from 8 workers with occupational activity as a supervisor and sprayer. Airborne Paraquat residue was measured for 25 minutes during spraying by using personal air sampler at worker's breathing zone. Airborne Paraquat residue was detected by High Performance Liquid Chromatography (HPLC) with NIOSH 5003 methods. The average of airborne Paraquat residue was 0.0125 mg/m3, it values was less than the Threshold Limit Value (0.05 mg/m3) of American Conference of Government Industrial Hygienists, but the average of potential inhalation dose was 0.001 mg/kg/day for worker's weight 55 kg, it was value higher than Acceptable Operator Exposure Limit (0.0005 mg/kg/day) and the calculation of Risk Quotient (RQ) was more than 1, it conditions was unacceptable for workers. Although, airborne Paraquat residue were safe, but potential inhalation dose and Risk Quotient (RQ) were unsafe for workers, cause it can be lead to lung function disorders. Therefore, for further studies it was necessary to assess the lung function of workers and the use of personal protective equipment must be completely and standard

Proteomics of Cytochrome c Oxidase-Negative versus -Positive Muscle Fiber Sections in Mitochondrial Myopathy

The mosaic distribution of cytochrome c oxidase(+) (COX+) and COX - muscle fibers in mitochondrial disorders allows the sampling of fibers with compensated and decompensated mitochondrial function from the same individual. We apply laser capture microdissection to excise individual COX+ and COX- fibers from the biopsies of mitochondrial myopathy patients. Using mass spectrometry-based proteomics, we quantify >4,000 proteins per patient. While COX+ fibers show a higher expression of respiratory chain components, COX- fibers display protean adaptive responses, including upregulation of mitochondrial ribosomes, translation proteins, and chaperones. Upregulated proteins include C1QBP, required for mitoribosome formation and protein synthesis, and STOML2, which organizes cardiolipin-enriched microdomains and the assembly of respiratory supercomplexes. Factoring in fast/slow fiber type, COX (-) slow fibers show a compensatory upregulation of beta-oxidation, the AAA(+) protease AFG3L1, and the OPA1-dependent cristae remodeling program. These findings reveal compensatory mechanisms in muscle fibers struggling with energy shortage and metabolic stress

Aplikasi Dan Tinjauan Teknis Direct Sequence Code Division Multiple Access (D S-cdma)

Direct Sequence Code Division Multiple Access (DS-CDMA) sering disebut CDMA saja,merupakan teknik multiple akses yang banyak digunakan dalam komunikasi bergerak,memanfaatkan teknik spread spectrum, dimana sejumlah pengguna dapat menggunakan lebarpita frekuensi dalam waktu yang bersamaan. Kanal tiap pengguna dibedakan oleh kode unikyang digunakan untuk menebarkan daya sinyal informasi pada pita frekuensi yang jauh lebihlebar dibandingkan pita frekuensi sinyal informasi. Kualitas sistem ditentukan oleh Sinyal to Noiserasio (S/N), Sinyal to Noise rasio total perbit (Eb/No), power control, dan processing gain (Pg)atau spreading factor yang akan menentukan jumlah pengguna yang dapat ditangani olehsistem. Keunggulan teknologi ini yaitu tidak membutuhkan equalizer, satu radio per site, tidakmembutuhkan guard time dan guard band, tidak membutuhkan alokasi dan pengelolaanfrekuensi, daya pancar rendah, soft handoff, dan lebih kebal terhadap penyadapan danjamming