3,333 research outputs found
Spin dependent fragmentation function at Belle
The measurement of the so far unknown chiral-odd quark transverse spin
distribution in either semi-inclusive DIS (SIDIS) or inclusive measurements in
pp collisions at RHIC has an additional chiral-odd fragmentation function
appearing in the cross section. These chiral-odd fragmentation functions (FF)
can for example be the so-called Collins FF or the Interference FF. HERMES has
given a first hint that these FFs are nonzero, however in order to measure the
transversity one needs these FFs to be precisely known. We have used 29.0
fb of data collected by the Belle experiment at the KEKB
collider to measure azimuthal asymmetries for different charge combinations of
pion pairs and thus access the Collins FF.Comment: Results presented at the DIS 2006 conference in Tsukuba, Japa
Characterization and Commissioning of a Ka-Band Ground Station for Cognitive Algorithm Development
In 2018, the Cognitive Communications and Propagation projects completed installation and checkout testing of a new Ka-Band ground station at the NASA Glenn Research Center in Cleveland, Ohio. The Cognitive Algorithms Demonstration Testbed (CADeT) was developed to provide a fully characterized and controllable dynamic link environment to researchers looking to demonstrate hardware and software aligned with atmospheric sensing and cognitive algorithms. CADeT integrates a host of precision control and measurement systems in addition to repurposing a 5.5 meter beam-waveguide dish platform previously used with the Advanced Communications Technology Satellite (ACTS). This paper will discuss the laboratory testing of ground station components with a emphasis on elements vital to achieving link budget requirements including characterization of the new Gallium Nitride (GaN) Solid State Power Amplifier (SSPA) and far-field measurements of the new antenna feed. Finally, the paper discusses in-situ tests conducted with CADeT and the Tracking and Data Relay Satellite System (TDRSS) to validate laboratory results and make necessary link budget adjustments before reviewing the lessons learned
C-terminal fusion of eGFP to the bradykinin B-2 receptor strongly affects down-regulation but not receptor internalization or signaling
A functional comparison was made between the wildtype bradykinin B, receptor (B(2)wt) and the chimera B(2)eGFP (enhanced green-fluorescent protein fused to the C-terminus of B(2)Wt), both stably expressed in HEK 293 cells. There was almost no difference in terms of ligand-inducible receptor phosphorylation and internalization, signal transduction (accumulation of inositol phosphates) or expression and affinity. However, stimulation for up to 8 h with 10 mu M bradykinin (BK) resulted in a strong decrease in surface receptors (by 60% within 5 h) in B(2)Wt, but not in B(2)eGFP. When the expression levels of both constructs where comparably reduced using a weaker promoter, long-term stimulation resulted in a reduction in surface receptors for B(2)wt(low) to less than 20% within 1 h, whereas the chimera B(2)eGFP(low) still displayed 50% binding activity after 2 h. A 1-h incubation in the absence of BK resulted in a recovery of 60% of the binding in B(2)wt(low) after 1-h stimulation with BK, but of only 20% after 7-h stimulation. In contrast, B(2)eGFP(low) levels were restored to more than 70%, even after 7-h stimulation. These data indicate that although the fusion of eGFP to B(2)wt does not affect its ligand-induced internalization, it strongly reduces the down-regulation, most likely by promoting receptor recycling over degradation
Decidability of the Monadic Shallow Linear First-Order Fragment with Straight Dismatching Constraints
The monadic shallow linear Horn fragment is well-known to be decidable and
has many application, e.g., in security protocol analysis, tree automata, or
abstraction refinement. It was a long standing open problem how to extend the
fragment to the non-Horn case, preserving decidability, that would, e.g.,
enable to express non-determinism in protocols. We prove decidability of the
non-Horn monadic shallow linear fragment via ordered resolution further
extended with dismatching constraints and discuss some applications of the new
decidable fragment.Comment: 29 pages, long version of CADE-26 pape
Voltage-controlled electron-hole interaction in a single quantum dot
The ground state of neutral and negatively charged excitons confined to a
single self-assembled InGaAs quantum dot is probed in a direct absorption
experiment by high resolution laser spectroscopy. We show how the anisotropic
electron-hole exchange interaction depends on the exciton charge and
demonstrate how the interaction can be switched on and off with a small dc
voltage. Furthermore, we report polarization sensitive analysis of the
excitonic interband transition in a single quantum dot as a function of charge
with and without magnetic field.Comment: Conference Proceedings, Physics and Applications of Spin-Related
Phenomena in Semiconductors, Santa Barbara (CA), 2004. 4 pages, 4 figures;
content as publishe
The Fermionic Density-functional at Feshbach Resonance
We consider a dilute gas of neutral unpolarized fermionic atoms at zero
temperature.The atoms interact via a short range (tunable) attractive
interaction. We demonstrate analytically a curious property of the gas at
unitarity. Namely, the correlation energy of the gas, evaluated by second order
perturbation theory, has the same density dependence as the first order
exchange energy, and the two almost exactly cancel each other at Feshbach
resonance irrespective of the shape of the potential, provided . Here is the range of the two-body potential, and is
defined through the number density . The implications of this
result for universality is discussed.Comment: Five pages, one table. accepted for publication in PR
What do Babies hear? Analyses of Child- and Adult-Directed Speech
Child-directed speech is argued to facilitate language development, and is found cross-linguistically and cross-culturally to varying degrees. However, previous research has generally focused on short samples of child-caregiver interaction, often in the lab or with experimenters present. We test the generalizability of this phenomenon with an initial descriptive analysis of the speech heard by young children in a large, unique collection of naturalistic, daylong home recordings. Trained annotators coded automatically-detected adult speech 'utterances' from 61 homes across 4 North American cities, gathered from children (age 2-24 months) wearing audio recorders during a typical day. Coders marked the speaker gender (male/female) and intended addressee (child/adult), yielding 10,886 addressee and gender tags from 2,523 minutes of audio (cf. HB-CHAAC Interspeech ComParE challenge; Schuller et al., in press). Automated speaker-diarization (LENA) incorrectly gender-tagged 30% of male adult utterances, compared to manually-coded consensus. Furthermore, we find effects of SES and gender on child-directed and overall speech, increasing child-directed speech with child age, and interactions of speaker gender, child gender, and child age: female caretakers increased their child-directed speech more with age than male caretakers did, but only for male infants. Implications for language acquisition and existing classification algorithms are discussed
Trypanosoma evansi e trypanosoma vivax: biologia, diagnóstico e controle.
Tripanosomoses; Taxonomia; Morfologia; Ciclo vital; Teminologia utiilzada para os tripanosomas baseada no Trypanosoma brucei; Manutenção dos Tripanosomas; Variação molecular em Tripanosomas; Ecologia e sociologia da variação antigênica; Genética de populações de Tripanosomas; Diagnóstico; Caracterização molecular; Métodos de controle; Resistência à drogas; Avaliação do uso do tratamento profilático estratégico ou curativo; Quimioterapia da Tripanosomose por Trypanosoma evansi (tratamento curativo); Quimioterapia da Tripanosomose por Trypanosoma vivax (tratamento curativo); Controle estratégico do Trypanosoma evansi através do uso de drogas tripanocidas; Controle estratégico do Trypanosoma vivax através do uso de drogas tripanocidas; Comparação do Isometamidium e Brometo de Homidium como droga profilática; Mecanismos experimentais de liberação lenta contendo Brometo de Homidium e Isometamidium; Análise econômica; Controle dos vetores; Controle através do uso de inseticidas; Piretroides; Utilização de armadilhas impregnadas com inseticidas
Absorption and photoluminescence spectroscopy on a single self-assembled charge-tunable quantum dot
We have performed detailed photoluminescence (PL) and absorption spectroscopy
on the same single self-assembled quantum dot in a charge-tunable device. The
transition from neutral to charged exciton in the PL occurs at a more negative
voltage than the corresponding transition in absorption. We have developed a
model of the Coulomb blockade to account for this observation. At large
negative bias, the absorption broadens as a result of electron and hole
tunneling. We observe resonant features in this regime whenever the quantum dot
hole level is resonant with two-dimensional hole states located at the capping
layer-blocking barrier interface in our structure.Comment: 6 pages, 6 figure
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