15,923 research outputs found
Taxonomy of the extrasolar planet
When a star is described as a spectral class G2V, we know that the star is
similar to our Sun. We know its approximate mass, temperature, age, and size.
When working with an extra-solar planet database, it is very useful to have a
taxonomy scale (classification) such as, for example, the Harvard
classification for stars. The taxonomy has to be easily interpreted and present
the most relevant information about extra-solar planets. I propose the
following the extra-solar planet taxonomy scale with four parameters. The first
parameter concerns the mass of an extra-solar planet in the form of the units
of the mass of other known planets, where M represents the mass of Mercury, E
that of Earth, N Neptune, and J Jupiter. The second parameter is the planet's
distance from its parent star (semi-major axis) described in logarithm with
base 10. The third parameter is the mean Dyson temperature of the extra-solar
planet, for which I established four main temperature classes; F represents the
Freezing class, W the Water Class, G the Gaseous Class, and R the Roasters
Class. I devised one additional class, however: P, the Pulsar Class, which
concerns extra-solar planets orbiting pulsar stars. The fourth parameter is
eccentricity. If the attributes of the surface of the extra-solar planet are
known, we are able to establish this additional parameter where t represents a
terrestrial planet, g a gaseous planet, and i an ice planet. According to this
taxonomy scale, for example, Earth is 1E0W0t, Neptune is 1N1.5F0i, and
extra-solar planet 55 Cnc e is 9E-1.8R1. Key words: Catalogues - Extra-solar
planet - Habitable zone - PlanetsComment: 11 pages, 1 figure, 4 table
Structural transitions in the 309-atom magic number Lennard-Jones cluster
The thermal behaviour of the 309-atom Lennard-Jones cluster, whose structure
is a complete Mackay icosahedron, has been studied by parallel tempering Monte
Carlo simulations. Surprisingly for a magic number cluster, the heat capacity
shows a very pronounced peak before melting, which is attributed to several
coincident structural transformation processes. The main transformation is
somewhat akin to surface roughening, and involves a cooperative condensation of
vacancies and adatoms that leads to the formation of pits and islands one or
two layers thick on the Mackay icosahedron. The second transition in order of
importance involves a whole scale transformation of the cluster structure, and
leads to a diverse set of twinned structures that are assemblies of
face-centred-cubic tetrahedra with 6 atoms along their edges, i.e., one atom
more than the edges of the 20 tetrahedra that make up the 309-atom Mackay
icosahedron. A surface reconstruction of the icosahedron from a Mackay to an
anti-Mackay overlayer is also observed, but with a lower probability.Comment: 7 pages, 4 figure
A Good Idea is Not Enough: Understanding the Challenges of Entrepreneurship Communication
This paper addresses a less-investigated issue of innovations: entrepreneurship communication. Business and marketing studies demonstrate that new product development processes do not succeed on good technical invention alone. To succeed, the invention must be appropriately communicated to a market and iterated through dialogue with potential stakeholders.
We explore this issue by examining communication-related challenges, abilities and barriers from the perspectives of innovators trying to enter an unfamiliar, foreign market. Specifically, we summarize results of a set of studies conducted in the Gyeonggi Innovation Program (GIP), an entrepreneurship program formed by a partnership between the University of Texas at Austin and Gyeonggi-Do Province in South Korea. Through the GIP, Korean entrepreneurs attempt to expand domestically successful product ideas to the American market. The study results demonstrate that these innovators must deal with a broad range of challenges, particularly (1) developing deeper understanding of market needs, values, and cultural expectations, and (2) producing pitches with the structure, claims and evidence, and engagement strategies expected by American stakeholders. These studies confirm that a deeper understanding of successful new product development (NPD) projects requires not only a culturally authentic NPD process model, but also communication-oriented research.
The GIP approach offers insights into good programmatic concept and effective methods for training engineers to become entrepreneurs. Yet we also identify potential improvements for such programs. Finally, we draw implications for studying entrepreneurship communication.IC2 Institut
Primary Coenzyme Q10 Deficiency
open4siCLINICAL CHARACTERISTICS:
Primary coenzyme Q10 (CoQ10) deficiency is usually associated with multisystem involvement, including neurologic manifestations such as fatal neonatal encephalopathy with hypotonia; a late-onset slowly progressive multiple-system atrophy-like phenotype (neurodegeneration with autonomic failure and various combinations of parkinsonism and cerebellar ataxia, and pyramidal dysfunction); and dystonia, spasticity, seizures, and intellectual disability. Steroid-resistant nephrotic syndrome (SRNS), the hallmark renal manifestation, is often the initial manifestation either as isolated renal involvement that progresses to end-stage renal disease (ESRD), or associated with encephalopathy (seizures, stroke-like episodes, severe neurologic impairment) resulting in early death. Hypertrophic cardiomyopathy (HCM), retinopathy or optic atrophy, and sensorineural hearing loss can also be seen.
DIAGNOSIS/TESTING:
The diagnosis of primary CoQ10 deficiency in a proband is established by identification of biallelic pathogenic variants in one of the nine genes encoding proteins directly involved in the synthesis of coenzyme Q10 or by detection of reduced levels of CoQ10 (ubiquinone) in skeletal muscle or reduced activities of complex I+III and II+III of the mitochondrial respiratory chain on frozen muscle homogenates.
MANAGEMENT:
Treatment of manifestations: In individuals with primary CoQ10 deficiency early treatment with high-dose oral CoQ10 supplementation (ranging from 5 to 50 mg/kg/day) can limit disease progression and reverse some manifestations; however, established severe neurologic and/or renal damage cannot be reversed. ACE inhibitors may be used in combination with CoQ10 supplementation in persons with proteinuria; renal transplantation is an option for those with ESRD. Treatment of hypertrophic cardiomyopathy, retinopathy, and sensorineural hearing loss is per usual practice. Prevention of primary manifestations: Supplementation with high-dose oral CoQ10 can prevent progression of the renal disease and onset of neurologic manifestations. Surveillance: Periodic neurologic evaluation, urine analysis (for proteinuria) and renal function tests, ophthalmologic evaluation, and audiometry. Evaluation of relatives at risk: Presymptomatic diagnosis for the purpose of early treatment with CoQ10 supplementation is warranted for relatives at risk.
GENETIC COUNSELING:
Primary coenzyme Q10 deficiency is inherited in an autosomal recessive manner. At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Carrier testing for at-risk relatives, prenatal testing for pregnancies at increased risk, and preimplantation genetic diagnosis are possible if the pathogenic variants in a family are known.openSalviati, L; Trevisson, E; Doimo, M; Navas, PSalviati, Leonardo; Trevisson, Eva; Doimo, Mara; Navas, P
Identifying Blue Horizontal Branch Stars Using the z Filter
In this paper we present a new method for selecting blue horizontal branch
(BHB) candidates based on color-color photometry. We make use of the Sloan
Digital Sky Survey z band as a surface gravity indicator and show its value for
selecting BHB stars from quasars, white dwarfs and main sequence A type stars.
Using the g, r, i, and z bands, we demonstrate that extraction accuracies on
par with more traditional u, g, and r photometric selection methods may be
achieved. We also show that the completeness necessary to probe major Galactic
structure may be maintained. Our new method allows us to efficiently select BHB
stars from photometric sky surveys that do not include a u band filter such as
the Panoramic Survey Telescope and Rapid Response System.Comment: Accepted for publication in The Astronomical Journa
Quantized Landau level spectrum and its density dependence
Scanning tunneling microscopy and spectroscopy in magnetic field was used to
study Landau quantization in graphene and its dependence on charge carrier
density. Measurements were carried out on exfoliated graphene samples deposited
on a chlorinated SiO2 thermal oxide which allowed observing the Landau level
sequences characteristic of single layer graphene while tuning the density
through the Si backgate. Upon changing the carrier density we find abrupt jumps
in the Fermi level after each Landau level is filled. Moreover, the Landau
level spacing shows a marked increase at low doping levels, consistent with an
interaction-induced renormalization of the Dirac cone.Comment: 11 pages, 4 figure
Riordan Paths and Derangements
Riordan paths are Motzkin paths without horizontal steps on the x-axis. We
establish a correspondence between Riordan paths and
-avoiding derangements. We also present a combinatorial proof
of a recurrence relation for the Riordan numbers in the spirit of the
Foata-Zeilberger proof of a recurrence relation on the Schr\"oder numbers.Comment: 9 pages, 2 figure
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