1,928 research outputs found

    Plane waves with negative phase velocity in Faraday chiral mediums

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    The propagation of plane waves in a Faraday chiral medium is investigated. Conditions for the phase velocity to be directed opposite to the direction of power flow are derived for propagation in an arbitrary direction; simplified conditions which apply to propagation parallel to the distinguished axis are also established. These negative phase-velocity conditions are explored numerically using a representative Faraday chiral medium, arising from the homogenization of an isotropic chiral medium and a magnetically biased ferrite. It is demonstrated that the phase velocity may be directed opposite to power flow, provided that the gyrotropic parameter of the ferrite component medium is sufficiently large compared with the corresponding nongyrotropic permeability parameters.Comment: accepted for publication in Phys. Rev.

    Nuclear Structure Studies of Light-Mass Radon Isotopes Using the 209-Bi(6-Li,xnγ) Reactions

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    This work was supported by National Science Foundation Grant PHY 75-00289 and Indiana Universit

    Een onderzoek naar het voorkomen en de oorzaken van de verschijnselen, welke worden aangeduid met den naam "ontginningsziekte"

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    11 apparently diseased soils gave the same general symptoms of 'reclamation disease' with oats and peas in pot experiments. The number of microbes was smaller and the proportion fungi/microbes was always larger in diseased soils than in similar normal soils. As soil sterilisation brought no cure, the disease could not be ascribed to microbes. The widespread opinion that the disease occurred on a certain black peat (Du. Gliede) was confirmed by pot experiments, also if Gliede was mixed with sand.Two groups of organic substances could be separated by hot ethanolic extraction, one coming out of solution after cooling, the other remaining in solution. From the solution a crystalline substance could be obtained, afterwards called 'Gliedine', causing disease symptoms after application to peas and oats. At minute concentrations it stimulated growth of oats. The residue caused grey speck disease in oats.Fertilizer trials with differently diseased soils showed that only compost or CuSO4 could restore the soil (also in the 2nd year).As 'Gliedine' slowly evaporated at 100 'C diseased soils were heated 3 h per day for 3 days, resulting in restoration of slightly diseased soils, almost cure of moderately diseased soils, and delay of disease symptoms on very diseased soils.The curing effect Of CUS04 must very probably be ascribed to the formation of an insoluble compound with 'Gliedine'</p

    Stream Fish Fauna From The Tributaries Of The Upper Itapetininga River, Upper Paranapanema River Basin, State Of São Paulo, Brazil

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The study area, which is located in urban and rural areas within the upper Paranapanema River basin, is undergoing several types of anthropogenic and non-anthropogenic impacts, such as chemical alterations, habitat disruption, and biological invasions. The aim of this study is to describe the fish faunal composition from tributaries of the Itapetininga River, upper Paranapanema River basin, state of São Paulo, Brazil. Herein, we include a list of 49 fish species, belonging to seven orders, 19 families and 35 genera, captured from September 2009 to November 2013. Thus, the present study fills part of the knowledge gap about the fish fauna from tributaries of the Paranapanema basin by adding data from small tributaries not studied so far. Moreover, our findings can help inform future conservational and/or management strategies within the upper Paranapanema basin. © 2016 Check List and Authors.12207/50981-7, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo07/50982-3, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2012/09346-4, FAPESP, Fundação de Amparo à Pesquisa do Estado de São PauloFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    The normal ranges of cardiovascular parameters measured using the ultrasonic cardiac output monitor

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    The ultrasonic cardiac output monitor (USCOM) is a noninvasive transcutaneous continuous wave Doppler method for assessing hemodynamics. There are no published reference ranges for normal values in adults (aged 18– 60 years) for this device. This study aimed to (1) measure cardiovascular indices using USCOM in healthy adults aged 18–60 years; (2) combine these data with those for healthy children (aged 0–12), adolescents (aged 12–18), and the elderly (aged over 60) from our previously published studies in order to present normal ranges for all ages, and (3) establish normal ranges of USCOM-derived variables according to both weight and age. This was a population- based cross-sectional observational study of healthy Chinese subjects aged 0.5–89 years in Hong Kong. USCOM scans were performed on all subjects, to produce measurements including stroke volume, cardiac output, and systemic vascular resistance. Data from previously published studies (children, adolescents, and the elderly) were included. Normal ranges were defined as lying between the 2.5th and 97.5th percentiles. A total of 2218 subjects were studied (mean age = 16.4, range = 0.5–89; 52% male). From previous studies, 1197 children (aged 0–12, 55% male), 590 adolescents (aged 12–18, 49% male), and 77 elderly (aged 60–89, 55% male) were included. New data were collected from 354 adults aged 18–60 (47% male). Normal ranges are presented according to age and weight. We present comprehensive normal ranges for hemodynamic parameters obtained with USCOM in healthy subjects of all ages from infancy to the elderly

    Long-term pair bonds in Harlequin Ducks.

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    We documented the frequency of pair reunion in Harlequin Ducks (Histrionicus histrionicus) on breeding streams in Alberta, and at a molting/wintering area in southwestern British Columbia. As long as their mate is alive, Harlequin Duck pairs reunite on the wintering area and return to the breeding stream together. Pairs reunite even if the female is unsuccessful at breeding the previous season, which suggests that reuniting with the same mate year after year is important. Some males that have lost their mate and fail to re-pair on the wintering area show fidelity to their former breeding site

    A measurement of parity-violating gamma-ray asymmetries in polarized cold neutron capture on 35Cl, 113Cd, and 139La

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    An apparatus for measuring parity-violating asymmetries in gamma-ray emission following polarized cold neutron capture was constructed as a 1/10th scale test of the design for the forthcoming n+p->d+gamma experiment at LANSCE. The elements of the polarized neutron beam, including a polarized 3He neutron spin filter and a radio frequency neutron spin rotator, are described. Using CsI(Tl) detectors and photodiode current mode readout, measurements were made of asymmetries in gamma-ray emission following neutron capture on 35Cl, 113Cd, and 139La targets. Upper limits on the parity-allowed asymmetry sn⋅(kγ×kn)s_n \cdot (k_{\gamma} \times k_n) were set at the level of 7 x 10^-6 for all three targets. Parity-violating asymmetries sn⋅kγs_n \cdot k_{\gamma} were observed in 35Cl, A_gamma = (-29.1 +- 6.7) x 10^-6, and 139La, A_gamma = (-15.5 +- 7.1) x 10^-6, values consistent with previous measurements.Comment: 19 pages, 4 figures, submitted to Nucl. Instr. and Meth.
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