5,584 research outputs found
Spacetime Fermions in Light-cone Gauge Superstring Field Theory and Dimensional Regularization
We consider the dimensional regularization of the light-cone gauge type II
superstring field theories in the NSR formalism. In the previous work, we have
calculated the tree-level amplitudes with external lines in the (NS,NS) sector
using the regularization and shown that the desired results are obtained
without introducing contact term interactions. In this work, we study the
tree-level amplitudes with external lines in the Ramond sector. In order to
deal with them, we propose a worldsheet theory to be used instead of that for
the naive dimensional regularization. With the worldsheet theory, we regularize
and define the tree-level amplitudes by analytic continuation. We show that the
results coincide with those of the first quantized formulation.Comment: 28 pages, 5 figures; v2: more details of our manipulations in
subsection 3.2 added, figures and references added; v3: clarifications adde
Ethyl 2-methyl-5-oxo-4-(3,4,5-trimethoxyphenyl)-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate
In the molecular structure of the title compound, C22H27NO6, the dihydropyridine ring adopts a flattened boat conformation while the cyclohexenone ring is in an envelope conformation. In the crystal, molecules stack parallel to the crystallographic a axis linked by intermolecular N—H⋯O and C—H⋯O hydrogen bonds
Shielding Effectiveness of Laminated Shields
Shielding prevents coupling of undesired radiated electromagnetic energy into equipment otherwise susceptible to it. In view of this, some studies on shielding effectiveness of laminated shields with conductors and conductive polymers using plane-wave theory are carried out in this paper. The plane wave shielding effectiveness of new combination of these materials is evaluated as a function of frequency and thickness of material. Conductivity of the polymers, measured in previous investigations by the cavity perturbation technique, is used to compute the overall reflection and transmission coefficients of single and multiple layers of the polymers. With recent advances in synthesizing stable highly conductive polymers these lightweight mechanically strong materials appear to be viable alternatives to metals for EM1 shielding
Deterministic meeting of sniffing agents in the plane
Two mobile agents, starting at arbitrary, possibly different times from
arbitrary locations in the plane, have to meet. Agents are modeled as discs of
diameter 1, and meeting occurs when these discs touch. Agents have different
labels which are integers from the set of 0 to L-1. Each agent knows L and
knows its own label, but not the label of the other agent. Agents are equipped
with compasses and have synchronized clocks. They make a series of moves. Each
move specifies the direction and the duration of moving. This includes a null
move which consists in staying inert for some time, or forever. In a non-null
move agents travel at the same constant speed, normalized to 1. We assume that
agents have sensors enabling them to estimate the distance from the other agent
(defined as the distance between centers of discs), but not the direction
towards it. We consider two models of estimation. In both models an agent reads
its sensor at the moment of its appearance in the plane and then at the end of
each move. This reading (together with the previous ones) determines the
decision concerning the next move. In both models the reading of the sensor
tells the agent if the other agent is already present. Moreover, in the
monotone model, each agent can find out, for any two readings in moments t1 and
t2, whether the distance from the other agent at time t1 was smaller, equal or
larger than at time t2. In the weaker binary model, each agent can find out, at
any reading, whether it is at distance less than \r{ho} or at distance at least
\r{ho} from the other agent, for some real \r{ho} > 1 unknown to them. Such
distance estimation mechanism can be implemented, e.g., using chemical sensors.
Each agent emits some chemical substance (scent), and the sensor of the other
agent detects it, i.e., sniffs. The intensity of the scent decreases with the
distance.Comment: A preliminary version of this paper appeared in the Proc. 23rd
International Colloquium on Structural Information and Communication
Complexity (SIROCCO 2016), LNCS 998
The Galactic black hole transient H1743-322 during outburst decay: connections between timing noise, state transitions and radio emission
Multi-wavelength observations of Galactic black hole transients during
outburst decay are instrumental for our understanding of the accretion geometry
and the formation of outflows around black hole systems. H1743-322, a black
hole transient observed intensely in X-rays and also covered in the radio band
during its 2003 decay, provides clues about the changes in accretion geometry
during state transitions and also the general properties of X-ray emission
during the intermediate and the low-hard states. In this work, we report on the
evolution of spectral and temporal properties in X-rays and the flux in the
radio band with the goal of understanding the nature of state transitions
observed in this source. We concentrate on the transition from the thermal
dominant state to the intermediate state that occurs on a timescale of one day.
We show that the state transition is associated with a sudden increase in
power-law flux. We determine that the ratio of the power-law flux to the
overall flux in the 3--25 keV band must exceed 0.6 to observe strong timing
noise. Even after the state transition, once this ratio was below 0.6, the
system transited back to the thermal dominant state for a day. We show that the
emission from the compact radio core does not turn on during the transition
from the thermal dominant state to the intermediate state but does turn on when
the source reaches the low-hard state, as seen in 4U 1543-47 and GX 339-4. We
find that the photon index correlates strongly with the QPO frequency and
anti-correlates with the rms amplitude of variability. We also show that the
variability is more likely to be associated with the power-law emission than
the disk emission.Comment: 23 pages, 5 Figures, 1 Table, accepted for publication in Ap
Instability Heating of Sympathetically-Cooled Ions in a Linear Paul Trap
Sympathetic laser cooling of ions stored within a linear-geometry, radio
frequency, electric-quadrupole trap has been investigated using computational
and theoretical techniques. The simulation, which allows 5 sample ions to
interact with 35 laser-cooled atomic ions, revealed an instability heating
mechanism, which can prevent ions below a certain critical mass from being
sympathetically cooled. This critical mass can however be varied by changing
the trapping field parameters thus allowing ions with a very large range of
masses to be sympathetically cooled using a single ion species. A theoretical
explanation of this instability heating mechanism is presented which predicts
that the cooling-heating boundary in trapping parameter space is a line of
constant (ion trap stability coefficient), a result supported by the
computational results. The threshold value of depends on the masses of
the interacting ions. A functional form of this dependence is given
Simulation of Deep Water Wave Climate for the Indian Seas
The ocean wave climate has a variety of applications in Naval defence. However, a long-term and reliable wave climate for the Indian Seas (The Arabian Sea and The Bay of Bengal) over a desired grid resolution could not be established so far due to several constraints. In this study, an attempt was made for the simulation of wave climate for the Indian Seas using the third-generation wave model (3g-WAM) developed by WAMDI group. The 3g-WAM as such was implemented at NPOL for research applications. The specific importance of this investigation was that, the model utilized a “mean climatic year of winds” estimated using historical wind measurements following statistical and probabilistic approaches as the winds which were considered for this purpose were widely scattered in space and time. Model computations were carried out only for the deep waters with current refraction. The gridded outputs of various wave parameters were stored at each grid point and the spectral outputs were stored at selected locations. Monthly, seasonal and annual distributions of significant wave parameters were obtained by post-processing some of the model outputs. A qualitative validation of simulated wave height and period parameters were also carried out by comparing with the observed data. The study revealed that the results of the wave climate simulation were quite promising and they can be utilized for various operational and ocean engineering applications.Therefore, this study will be a useful reference/demonstration for conducting such experiments in the areas where wind as well as wave measurements are insufficient
Bullying victimisation in adolescence: prevalence and inequalities by gender, socioeconomic status and academic performance across 71 countries
Background: Bullying victimisation is of global importance due to its long-term negative consequences. We examined the prevalence of victimisation and its inequalities in 15-year-olds across 71 countries. Methods: Data were from the Programme for International Student Assessment (March-August 2018). Students reported frequencies of relational, physical, and verbal victimisation during the last 12 months, which were analysed separately and combined into a total score. Prevalence of frequent victimisation (> a few times a month) was estimated, followed by mean differences in total score by gender, wealth and academic performance quintiles in each country. Meta-analyses were used to examine country differences. Findings: Of 421,437 students included, 113,602 (30·4%) experienced frequent victimisation, yet this varied by country-from 9·3% (Korea) to 64·8% (Philippines). Verbal and relational victimisation were more frequent (21·4%, 20.9%, respectively) than physical victimisation (15·2%). On average, boys (vs girls +0·23SD, 95%CI: 0·22-0·24), students from the lowest wealth (vs highest +0·09SD, 0·08-0·10) and with lowest academic performance (vs highest +0·49SD, 0·48-0·50) had higher scores. However, there was substantial between-country heterogeneity in these associations (I2=85%-98%). Similar results were observed for subtypes of victimisation-except relational victimisation, where gender inequalities were smaller. Interpretation: Globally, bullying victimisation was high, although the size, predominant subtype and strength of associations with risk factors varied by country. The large cross-country differences observed require further replication and empirical explanation, and suggest the need to and the large scope for reducing bullying victimisation and its inequity in the future. Funding: Japan Foundation for Pediatric Research
Does the score on the mrc strength scale reflect instrumented measures of maximal torque and muscle activity in post‐stroke survivors?
It remains unknown whether variation of scores on the Medical Research Council (MRC) scale for muscle strength is associated with operator‐independent techniques: dynamometry and surface electromyography (sEMG). This study aimed to evaluate whether the scores of the MRC strength scale are associated with instrumented measures of torque and muscle activity in post-stroke survivors with severe hemiparesis both before and after an intervention. Patients affected by a first ischemic or hemorrhagic stroke within 6 months before enrollment and with complete paresis were included in the study. The pre‐ and post‐treatment assessments included the MRC strength scale, sEMG, and dynamometry assessment of the triceps brachii (TB) and biceps brachii (BB) as measures of maximal elbow extension and flexion torque, respectively. Proprioceptive‐based training was used as a treatment model, which consisted of multidirectional exercises with verbal feedback. Each treatment session lasted 1 h/day, 5 days a week for a total 15 sessions. Nineteen individuals with stroke participated in the study. A significant correlation between outcome measures for the BB (MRC and sEMG p = 0.0177, ϱ = 0.601; MRC and torque p = 0.0001, ϱ = 0.867) and TB (MRC and sEMG p = 0.0026, ϱ = 0.717; MRC and torque p = 0.0001, ϱ = 0.873) were observed post intervention. Regression models revealed a relationship between the MRC score and sEMG and torque measures for both the TB and BB. The results confirmed that variation on the MRC strength scale is associated with variation in sEMG and torque measures, especially post intervention. The regression model showed a causal relationship between MRC scale scores, sEMG, and torque assessments
Molecular Typing of Canine Parvovirus from Sulaimani, Iraq and Phylogenetic Analysis Using Partial Vp2 Gene
Canine parvovirus (CPV) remains the most significant viral cause of haemorrhagic enteritis and bloody diarrhoea in puppies over the age of 12 weeks. The objective of the present study was to detect and genotype CPV-2 by polymerase chain reaction (PCR) and to perform phylogenetic analysis using partial VP2 gene sequences. We analysed eight faecal samples of unvaccinated dogs with signs of vomiting and bloody diarrhoea during the period from December 2013 to May 2014 in different locations in Sulaimani, Kurdistan, Iraq. After PCR detection, we found that all viral sequences in our study were CPV-2b variants, which differed genetically by 0.8% to 3.6% from five commercially available vaccines. Alignment between eight nucleotides of field virus sequences showed 95% to 99.5% similarity. The phylogenetic analysis for the 8 field sequences formed two distinct clusters with two sequences belonging to strains from China and Thailand and the other six - with a strain from Egypt. Molecular characterisation and CPV typing are crucial in epidemiological studies for future prevention and control of the disease
- …