5,087 research outputs found
PHYLOGENY of TWO AFRICAN GENERA of SAPOTACEAE - ENGLEROPHYTUM and SYNSEPALUM
Englerophytum and Synsepalum are two closely related genera of trees and shrubs from the African tropics. Previous molecular studies have shown that these genera collectively form a clade within the subfamily Chrysophylloideae (Sapotaceae). However, little is known about the inter-relationships of the taxa within the Englerophytum-Synsepalum clade. In this study, nuclear ribosomal DNA and plastid trnH-psbA sequences were used to estimate the phylogeny within the clade. Results indicate that the clade consists of six major lineages, two composed solely of taxa from the genus Englerophytum and four composed of taxa from the genus Synsepalum. Each lineage can be distinguished by suites of vegetative and floral characters. Leaf venation patterns, calyx fusion, style length and staminodal structure were among the most useful characters for distinguishing clades. Some of the subclades within the Englerophytum-Synsepalum clade were also found to closely fit descriptions of former genera, most of which were described by Aubréville, that have since been placed in synonymy with Englerophytum and Synsepalum. The clade with the type species of Englerophytum also contains the type species of the genera Wildemaniodoxa and Zeyherella, which are confirmed as synonyms. © Trustees of the Royal Botanic Garden Edinburgh (2019)
Plasma of Argon Affects the Earliest Biological Response of Different Implant Surfaces: An In Vitro Comparative Study
Status of Superconducting RF Linac Development for APT
This paper describes the development progress of high current superconducting
RF linacs in Los Alamos, performed to support a design of the linac for the APT
(Accelerator Production of Tritium) Project. The APT linac design includes a CW
superconducting RF high energy section, spanning an energy range of 211 to 1030
MeV, and operating at a frequency of 700 MHz with two constant beta sections
(beta of 0.64 and 0.82). In the last two years, we have progressed towards
build a cryomodule with beta of 0.64. We completed the designs of the 5 cell
superconducting cavities and the 210 kW power couplers. We are scheduled to
begin assembly of the cryomodule in September 2000. In this paper, we present
an overview of the status of our development efforts and a report on the
results of the cavity and coupler test program.Comment: LINAC2000 THD1
Caltech Faint Field Galaxy Redshift Survey IX: Source detection and photometry in the Hubble Deep Field Region
Detection and photometry of sources in the U_n, G, R, and K_s bands in a 9x9
arcmin^2 region of the sky, centered on the Hubble Deep Field, are described.
The data permit construction of complete photometric catalogs to roughly
U_n=25, G=26, R=25.5 and K_s=20 mag, and significant photometric measurements
somewhat fainter. The galaxy number density is 1.3x10^5 deg^{-2} to R=25.0 mag.
Galaxy number counts have slopes dlog N/dm=0.42, 0.33, 0.27 and 0.31 in the
U_n, G, R and K_s bands, consistent with previous studies and the trend that
fainter galaxies are, on average, bluer. Galaxy catalogs selected in the R and
K_s bands are presented, containing 3607 and 488 sources, in field areas of
74.8 and 59.4 arcmin^2, to R=25.5 and and K_s=20 mag.Comment: Accepted for publication in ApJS; some tables and slightly nicer
figures available at http://www.sns.ias.edu/~hogg/deep
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Scientific rationale of a Saturn probe mission
We describe the main scientific goals to be addressed by future in situ exploration of Saturn
Big data in economics: evolution or revolution?
The Big Data Era creates a lot of exciting opportunities for new developments in economics and econometrics. At the same time, however, the analysis of large datasets poses difficult methodological problems that should be addressed
appropriately and are the subject of the present chapter
Low temperature transition to a superconducting phase in boron-doped silicon films grown on (001)-oriented silicon wafers
We report on a detailed analysis of the superconducting properties of
boron-doped silicon films grown along the 001 direction by Gas Immersion Laser
Doping. The doping concentration cB has been varied up to approx. 10 at.% by
increasing the number of laser shots to 500. No superconductivity could be
observed down to 40mK for doping level below 2.5 at.%. The critical temperature
Tc then increased steeply to reach 0.6K for cB = 8 at%. No hysteresis was found
for the transitions in magnetic field, which is characteristic of a type II
superconductor. The corresponding upper critical field Hc2(0) was on the order
of 1000 G, much smaller than the value previously reported by Bustarret et al.
in Nature (London) 444, 465 (2006).Comment: 4 pages including 4 figures, submitted to PRB-Rapid Communicatio
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