1,935 research outputs found

    Simultaneous measurement of quality factor and wavelength shift by phase shift microcavity ring down spectroscopy

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    Optical resonant microcavities with ultra high quality factors are widely used for biosensing. Until now, the primary method of detection has been based upon tracking the resonant wavelength shift as a function of biodetection events. One of the sources of noise in all resonant-wavelength shift measurements is the noise due to intensity fluctuations of the laser source. An alternative approach is to track the change in the quality factor of the optical cavity by using phase shift cavity ring down spectroscopy, a technique which is insensitive to the intensity fluctuations of the laser source. Here, using biotinylated microtoroid resonant cavities, we show simultaneous measurement of the quality factor and the wavelength shift by using phase shift cavity ring down spectroscopy. These measurements were performed for disassociation phase of biotin-streptavidin reaction. We found that the disassociation curves are in good agreement with the previously published results. Hence, we demonstrate not only the application of phase shift cavity ring down spectroscopy to microcavities in the liquid phase but also simultaneous measurement of the quality factor and the wavelength shift for the microcavity biosensors in the application of kinetics measurements

    Taxonomic significance of leaf epidermal anatomy of selected Persicaria Mill. species of family Polygonaceae from Pakistan

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    Leaf epidermal anatomy of selected Persicaria Mill. species of the family Polygonaceae revealed variation in size and shape of epidermal cells, stomata, glandular and non glandular trichomes. This study proves to be taxonomically important tool in the delimitation of taxa. Epidermal cell shapes are variable but mostly polygonal. Five different stomatal patterns are reported for Persicaria Mill. Two types of non glandular trichomes are observed only in P. barbata, P. stagnina and P. orientalis which serve as their distinguishing characters. Glandular trichomes are 1, 2 and 4-celled peltate, capitate and spheroidal. Cluster analyses elucidate relationship among different taxa by utilization of leaf epidermal characters

    Proposing a Popular Method for Meteorological Drought Monitoring in the Kabul River Basin, Afghanistan

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    This paper investigates meteorological drought in one of Afghanistan's most important socio-economic river basins called Kabul River Basin (KRB) using a 38 years monthly precipitation data. Several drought indices such as Standardized Precipitation Index (SPI), Percent of Normal Precipitation Index (PNPI), Deciles Index (DI), and China-Z Index (CZI) were applied for the first time on the basin in order to observe the correlation among the indices in the basin for drought, and to see which method is suitable for drought monitoring in KRB. Due to the concerns that climate is changing and especially the rapid snowmelt that accounts for 80% of the precipitation in Afghanistan, it was essential to carry such a study in order to warn the responsible bodies in the country for a better drought management. Moreover, the rapid population increase and USAge of more water for both drinking and agricultural purposes in the basin with a possible decrease in the annual precipitation make it necessary to undertake such a study. The results of the investigation show that KRB area experienced drought conditions continuously from 2000 to 2004 with a peak extreme drought in 2001 which confirm to the reported worst drought in the region. It is noted that log-SPI, gamma-SPI, and Deciles captured the historical extreme and severe drought periods successfully, therefore, these methods are recommended to be applied to this region as drought assessment tools

    Kondisi Sosial Eonomi Petani Karet Desa Kembang Tanjung Lampung Utara Tahun 2016

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    The research aims to display the socio-economic condition of rubber farmers at Kembang Tanjung Village, South Abung Subdisctrict, North Lampung in 2016. Data were collecting through observation, questionnaire, and documentation. The results of the research showed that 1) Rubber farmers are mostly low-educated. Generally, the rubber farmers levels of formal education were Elementary (equally) 50 people (62.05%), (2) The average field width is 1.09 ha/each family, (3) Their average yearly income is Rp. 3,355,000/family to purchase fertilizer, medicines, and workers wage, (4) Average yearly production of each farmer is 4,007 kg/family, (5) Average yearly income of rubber farmers is Rp. 12,000,000/family, (6) The average number of rubber farmers children are 3 children, and (7) The minimum level of basic needs fulfillment of rubber farmers is 3.072.800/year.Penelitian ini bertujuan untuk menggambarkan Kondisi Sosial Ekonomi Petani Karet di Desa Kembang Tanjung Kecamatan Abung Selatan Kabupaten Lampung Utara Tahun 2016. Pengumpulan data dengan teknik observasi, kuesioner, dokumentasi. Hasil penelitian ini menunjukkan: (1) Petani karet berpendidikan rendah sebanyak 50 orang 62,05%, (2) Luas lahan petani karet rata-rata 1,09 ha/kk, (3) Rata-rata biaya sebesar Rp 3.355.000/tahun/KK. Biaya tersebut digunakan untuk pembelian pupuk, asam semut, obat-obatan dan upah tenaga kerja, (4) Rata-rata produksi yang diperoleh setiap petani 4.007 kg/KK, (5) Rata-rata pendapatan Rp 12.000.000/tahun/KK yang diperoleh setiap petani karet, (6) Jumlah anak yang dimiliki kepala keluarga petani karet dengan rata-rata 3 anak, dan (7) Tingkat pemenuhan kebutuhan pokok minimum petani karet yaitu Rp 3.072.800/tahun

    Strategy on Hepatitis B prevention among African undergraduate students of health sciences in Davangere, Karnataka India

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    Background: Hepatitis B is an inflammatory disease of the liver which is caused by Hepatitis B Virus. It is a global problem, with 66% of all the population living in areas where there are high levels of infections. Hepatitis B infection are due to lapses in the sterilization of instruments as well as improper waste management. Knowledge regarding Hepatitis B and safety precautions is needed to minimize the health care setting’s acquired infections among health personnel and students of health Sciences. Aim: The study was aimed at assessing the knowledge regarding the prevention of Hepatitis B among African Undergraduate students of Health Sciences in Davangere. Methodology: A cross sectional design was used for the study were 50 students were selected using purposive sampling. A validated structured questionnaire was used for data collection. The data were analyzed using median score and correlations. Results: The results indicated that majority (52%) of the respondents were between 22- 24years of age. The students of B.Pharm were 25 (50%), 38% MBBS and 12% B.Sc. Nursing. The overall median score on knowledge regarding hepatitis B Prevention was 13.0 out of maximum score of 29. The association between the knowledge on hepatitis B prevention strategy with level of study and course specialty was 0.74 P>0.05. Conclusion: The study concluded that the knowledge regarding Hepatitis B prevention among students was inadequate hence, recommends a similar study on a larger scale. Keywords: Knowledge; Prevention; Hepatitis B; Infection; African

    Phylogenetic analysis of Artemisia L. (Asteraceae) based on micromorphological traits of pollen grains

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    The phylogenetic relationships within the genus Artemisia have been very controversial. In order to recognize the systematic inference of pollen grains in this genus, the micromorphological characteristics of pollens from 22 taxa were examined by means of light microscopy (LM) and scanningelectron microscopy (SEM). A phylogenetic analysis of Artemisia based on 9 micromorphological characters of pollens was conducted using Wagner parsimony method. In the resulting phylogenetic tree, relationships among different Artemisia species are shown. This study also presents thephylogenetic associations among 4 sections within the genus Artemisia. The reunion of genus Seriphidum with Artemisia was also confirmed

    Andreev Reflection without Fermi surface alignment in High Tc_{c}-Topological heterostructures

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    We address the controversy over the proximity effect between topological materials and high Tc_{c} superconductors. Junctions are produced between Bi2_{2}Sr2_{2}CaCu2_{2}O8+δ_{8+\delta} and materials with different Fermi surfaces (Bi2_{2}Te3_{3} \& graphite). Both cases reveal tunneling spectra consistent with Andreev reflection. This is confirmed by magnetic field that shifts features via the Doppler effect. This is modeled with a single parameter that accounts for tunneling into a screening supercurrent. Thus the tunneling involves Cooper pairs crossing the heterostructure, showing the Fermi surface mis-match does not hinder the ability to form transparent interfaces, which is accounted for by the extended Brillouin zone and different lattice symmetries

    Noninvasive electron microscopy with interaction-free quantum measurements

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    We propose the use of interaction-free quantum measurements with electrons to eliminate sample damage in electron microscopy. This might allow noninvasive molecular-resolution imaging. We show the possibility of such measurements in the presence of experimentally measured quantum decoherence rates and using a scheme based on existing charged particle trapping techniques.David and Lucile Packard Foundatio

    Evidence for a New Excitation at the Interface Between a High-Tc Superconductor and a Topological Insulator

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    High-temperature superconductors exhibit a wide variety of novel excitations. If contacted with a topological insulator, the lifting of spin rotation symmetry in the surface states can lead to the emergence of unconventional superconductivity and novel particles. In pursuit of this possibility, we fabricated high critical-temperature (Tc ~ 85 K) superconductor/topological insulator (Bi2Sr2CaCu2O8+delta/Bi2Te2Se) junctions. Below 75 K, a zero-bias conductance peak (ZBCP) emerges in the differential conductance spectra of this junction. The magnitude of the ZBCP is suppressed at the same rate for magnetic fields applied parallel or perpendicular to the junction. Furthermore, it can still be observed and does not split up to at least 8.5 T. The temperature and magnetic field dependence of the excitation we observe appears to fall outside the known paradigms for a ZBCP
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