5,355 research outputs found
Properties and occurrence rates of exoplanet candidates as a function of host star metallicity from the DR25 catalog
Correlations between the occurrence rate of exoplanets and their host star
properties provide important clues about the planet formation processes. We
studied the dependence of the observed properties of exoplanets (radius, mass,
and orbital period) as a function of their host star metallicity. We analyzed
the planetary radii and orbital periods of over 2800 candidates from
the latest data release DR25 (Q1-Q17) with revised planetary radii
based on ~DR2 as a function of host star metallicity (from the Q1-Q17
(DR25) stellar and planet catalog). With a much larger sample and improved
radius measurements, we are able to reconfirm previous results in the
literature. We show that the average metallicity of the host star increases as
the radius of the planet increases. We demonstrate this by first calculating
the average host star metallicity for different radius bins and then
supplementing these results by calculating the occurrence rate as a function of
planetary radius and host star metallicity. We find a similar trend between
host star metallicity and planet mass: the average host star metallicity
increases with increasing planet mass. This trend, however, reverses for masses
: host star metallicity drops with increasing planetary
mass. We further examined the correlation between the host star metallicity and
the orbital period of the planet. We find that for planets with orbital periods
less than 10 days, the average metallicity of the host star is higher than that
for planets with periods greater than 10 days.Comment: 14 pages, 13 Figures, Accepted for publication in The Astronomical
Journa
On Cubic Graceful Labeling
A graph with n vertex and m edges is said to be cubic graceful labeling if its vertices are labeled with distinct integers {0,1,2,3,……..,m3} such that for each edge f*( uv) induces edge mappings are {13,23,33,……,m3}. A graph admits a cubic graceful labeling is called a cubic graceful graph. In this paper, we proved that , associate urp with u(r+1)1 of K1,P, fixed vertices vr and ur of two copies of Pn are cubic graceful
Square Sum Difference Product Prime Labeling of Some Tree Graphs
Square sum difference product prime labeling of a graph is the labeling of the vertices with {0,1,2---------,p-1} and the edges with absolute difference of the sum of the squares of the labels of the incident vertices and product of the labels of the incident vertices. The greatest common incidence number of a vertex (gcin) of degree greater than one is defined as the greatest common divisor of the labels of the incident edges. If the gcin of each vertex of degree greater than one is one, then the graph admits square sum difference product prime labeling. In this paper we investigate some tree graphs for square sum difference product prime labeling
Oblong Mean Prime Labeling of Some Snake Graphs
A graph labeling is an assignment of integers to the vertices or edges or both subject to certain conditions. The graph for which every edge(uv),the labels assigned to u and v are oblong numbers and for each vertex of degree at least 2, the g c d of the labels of the incident edges is 1. Here we characterize some snake graphs for oblong mean prime labeling
Distribution and abundance of pteropod and heteropod molluscs in the EEZ and adjoining waters of India
The pteropod and heteropod molluscs formed an Important constituent in the zooplankton of the EEZ of India and the
adjacent areas. Between them the pteropods dominated numerically over the heteropads in all situations. The average
density of pteropods in the area investigated was 734 (expressed as number per 1000 m3 of water) and heteropoda was33
Free Radical Scavenging, Cytotoxic and Hemolytic Activities from Leaves of Acacia nilotica (L.) Wild. ex. Delile subsp. indica (Benth.) Brenan
Dietary intake of phytochemicals having antioxidant activity is associated with a lower risk of mortality from many diseases. Therefore, the aim of this study was to determine the free radical scavenging, cytotoxic and hemolytic activities of leaves of Acacia nilotica by using various methods. The results of the present study revealed that ethanol extract was the most effective and IC50 value was found to be 53.6 μg mL−1 for Vero cell lines and 28.9 μg mL−1 for Hela cell lines in cytotoxicity assays. The zone of color retention was 14.2 mm in β-carotene bleaching assay, which was as significant as positive control, butylated hydroxy toluene. None of the tested extracts possessed any hemolytic activity against rat and human erythrocytes revealing their cytotoxic mechanism and non-toxicity. Thus, only the ethanol extract could be considered as a potential source of anticancer and antioxidant compounds. Further phytochemical studies will be performed for specification of the biologically active principles
Use of Hyperbaric Oxygen in Experimental Frost-Bite
Frost bite produced in rates by exposing them to -15 degree calcius and the extent of injury in the hind limbs and the tail was assessed at the end of 15 days. Hyperoxic treatment at normal atmospheric pressure and 1.5 atmosphere was given to experimental groups for 30 minutes daily for seven days in a hyperoxic chamber immediately after cold exposure. The controls were not given any treatment. Single oxygen treatment at normal atmosphere pressure was of no value, however, repeated hyperoxic treatment showed limited improvement but repeated treatment for seven days with hyperbaric oxygen at 1.5 atmosphere showed distinct recovery of frozen parts
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