5,847 research outputs found
Characteristics of events with metric-to-decahectometric type II radio bursts associated with CMEs and flares in relation to SEP events
A gradual solar energetic particle (SEP) event is thought to happen when
particles are accelerated at a shock due to a fast coronal mass ejection (CME).
To quantify what kind of solar eruptions can result in such SEP events, we have
conducted detailed investigations on the characteristics of CMEs, solar flares
and m-to-DH wavelength type II radio bursts (herein after m-to-DH type II
bursts) for SEP-associated and non-SEP-associated events, observed during the
period of 1997-2012. Interestingly, 65% of m-to-DH type II bursts associated
with CMEs and flares produced SEP events. The SEP-associated CMEs have higher
sky-plane mean speed, projection corrected speed, and sky-plane peak speed than
those of non-SEP-associated CMEs respectively by 30%, 39%, and 25%, even though
the two sets of CMEs achieved their sky-plane peak speeds at nearly similar
heights within LASCO field of view. We found Pearson's correlation coefficients
between the speeds of CMEs speeds and logarithmic peak intensity of SEP events
are cc = 0.62 and cc = 0.58, respectively. We also found that the
SEP-associated CMEs are on average of three times more decelerated (-21.52
m/s2) than the non-SEP-associated CMEs (-5.63 m/s2). The SEP-associated m type
II bursts have higher frequency drift rate and associated shock speed than
those of the non-SEP-associated events by 70% and 25% respectively. The average
formation heights of m and DH type II radio bursts for SEP-associated events
are lower than for non-SEP-associated events. 93% of SEP-associated events
originate from the western hemisphere and 65% of SEP-associated events are
associated with interacting CMEs. The obtained results indicate that, at least
for the set of CMEs associated with m-to-DH type II bursts, SEP-associated CMEs
are more energetic than those not associated with SEPs, thus suggesting that
they are effective particle accelerators.Comment: 19 pages, 10 figures, 3 tables, accepted for publication by ApS
Alveolar macrophages and Toll-like receptor 4 mediate ventilated lung ischemia reperfusion injury in mice.
BackgroundIschemia-reperfusion (I-R) injury is a sterile inflammatory process that is commonly associated with diverse clinical situations such as hemorrhage followed by resuscitation, transient embolic events, and organ transplantation. I-R injury can induce lung dysfunction whether the I-R occurs in the lung or in a remote organ. Recently, evidence has emerged that receptors and pathways of the innate immune system are involved in recognizing sterile inflammation and overlap considerably with those involved in the recognition of and response to pathogens.MethodsThe authors used a mouse surgical model of transient unilateral left pulmonary artery occlusion without bronchial involvement to create ventilated lung I-R injury. In addition, they mimicked nutritional I-R injury in vitro by transiently depriving cells of all nutrients.ResultsCompared with sham-operated mice, mice subjected to ventilated lung I-R injury had up-regulated lung expression of inflammatory mediator messenger RNA for interleukin-1β, interleukin-6, and chemokine (C-X-C motif) ligand-1 and -2, paralleled by histologic evidence of lung neutrophil recruitment and increased plasma concentrations of interleukin-1β, interleukin-6, and high-mobility group protein B1 proteins. This inflammatory response to I-R required toll-like receptor-4 (TLR4). In addition, the authors demonstrated in vitro cooperativity and cross-talk between human macrophages and endothelial cells, resulting in augmented inflammatory responses to I-R. Remarkably, the authors found that selective depletion of alveolar macrophages rendered mice resistant to ventilated lung I-R injury.ConclusionsThe data reveal that alveolar macrophages and the pattern recognition receptor toll-like receptor-4 are involved in the generation of the early inflammatory response to lung I-R injury
Pulsar Kicks With Modified URCA and Electrons in Landau Levels
We derive the energy asymmetry given the proto-neutron star during the time
when the neutrino sphere is near the surface of the proto-neutron star, using
the modified URCA process. The electrons produced with the anti-neutrinos are
in Landau levels due to the strong magnetic field, and this leads to asymmetry
in the neutrino momentum, and a pulsar kick. The magnetic field must be strong
enough for a large fraction of the eletrons to be in the lowest Landau level,
however, there is no direct dependence of our pulsar velocity on the strength
of the magnetic field. Our main prediction is that the large pulsar kicks start
at about 10 s and last for about 10 s, with the corresponding neutrinos
correlated in the direction of the magnetic field. We predict a pulsar velocity
of 1.03 km/s, which reaches 1000 km/s if T
K.Comment: 11 pages, 6 figure
Effect of Muons on the Phase Transition in Magnetised Proto-Neutron Star Matter
We study the effect of inclusion of muons and the muon neutrinos on the phase
transition from nuclear to quark matter in a magnetised proto-neutron star and
compare our results with those obtained by us without the muons. We find that
the inclusion of muons changes slightly the nuclear density at which transition
occurs.However the dependence of this transition density on various chemical
potentials, temperature and the magnetic field remains quantitatively the same.Comment: LaTex2e file with four postscript figure
Explicit MBR All-Symbol Locality Codes
Node failures are inevitable in distributed storage systems (DSS). To enable
efficient repair when faced with such failures, two main techniques are known:
Regenerating codes, i.e., codes that minimize the total repair bandwidth; and
codes with locality, which minimize the number of nodes participating in the
repair process. This paper focuses on regenerating codes with locality, using
pre-coding based on Gabidulin codes, and presents constructions that utilize
minimum bandwidth regenerating (MBR) local codes. The constructions achieve
maximum resilience (i.e., optimal minimum distance) and have maximum capacity
(i.e., maximum rate). Finally, the same pre-coding mechanism can be combined
with a subclass of fractional-repetition codes to enable maximum resilience and
repair-by-transfer simultaneously
Superpositions of the dual family of nonlinear coherent states and their non-classical properties
Nonlinear coherent states (CSs) and their {\it dual families} were introduced
recently. In this paper we want to obtain their superposition and investigate
their non-classical properties such as antibunching effect, quadrature
squeezing and amplitude squared squeezing. For this purpose two types of
superposition are considered. In the first type we neglect the normalization
factors of the two components of the dual pair, superpose them and then we
normalize the obtained states, while in the second type we superpose the two
normalized components and then again normalize the resultant states. As a
physical realization, the formalism will then be applied to a special physical
system with known nonlinearity function, i.e., Hydrogen-like spectrum. We
continue with the (first type of) superposition of the dual pair of
Gazeau-Klauder coherent states (GKCSs) as temporally stable CSs. An application
of the proposal will be given by employing the P\"oschl-Teller potential
system. The numerical results are presented and discussed in detail, showing
the effects of this special quantum interference.Comment: 19 pages, 18 figures, Accpeted for Publication in Optics
Communications, 201
Pharmacognostic Investigation of Clerodendrum Phlomidis Linn. F. Root
The present study was aimed to perform the pharmacognostic evaluation of Clerodendrum phlomidis Linn. f. root in terms of organoleptic, macro-microscopy, fluorescence analysis and physicochemical parameters. The characteristic macroscopic features showed that the root consists of 7-15 cm long, 0.2 -3.0 cm thick pieces which are cylindrical, tough and yellowish-brown externally, with hard fracture and slightly astringent taste. The main microscopic characters of the root shows exfoliating cork, having 10-15 rows of tangentially elongated, thick-walled cells. Cortex consists of round to oval parenchymatous cells, a few containing rhomboidal shaped calcium oxalate crystals. Endodermis consists of 3-4 layers of non-lignified, thick-walled rounded parenchymatous cells followed by a single pericyclic layer. Phloem consists of isodiametric, thin-walled, parenchymatous cells whereas xylem contains lignified pitted vessels. Medullary rays consisting of biseriate layer of lignified and radially elongated parenchymatous cells, is narrower in the xylem region while wider in the phloem region. Further, physicochemical analysis of the root power reports total ash, water soluble ash, sulphated ash as 7.8, 0.9 and 10.3 % w/w respectively. Successive extraction of the root powder with petroleum ether, chloroform, alcohol, water yielded 2.2, 2.4, 12.4 and 9.6 % w/w extracts respectively. Fluorescence study imparted characteristic colours to the root powder when observed under visible, short and long wavelength light. Various pharmacognostic parameters evaluated in this study helps in botanical identification and standardization of Clerodendrum phlomidis L. root part in crude form and provide the authentic data for the researchers and scientists involved in carrying out further research on this plant part
Thermal states of coldest and hottest neutron stars in soft X-ray transients
We calculate the thermal structure and quiescent thermal luminosity of
accreting neutron stars (warmed by deep crustal heating in accreted matter) in
soft X-ray transients (SXTs). We consider neutron stars with nucleon and
hyperon cores and with accreted envelopes. It is assumed that an envelope has
an outer helium layer (of variable depth) and deeper layers of heavier
elements, either with iron or with much heavier nuclei (of atomic weight A >
100) on the top (Haensel & Zdunik 1990, 2003, astro-ph/0305220). The relation
between the internal and surface stellar temperatures is obtained and fitted.
The quiescent luminosity of the hottest (low-mass) and coldest (high-mass)
neutron stars is calculated, together with the ranges of its possible
variations due to variable thickness of the helium layer. The results are
compared with observations of SXTs, particularly, containing the coldest (SAX
J1808.4-3658) and the hottest (Aql X-1) neutron stars. The observations of SAX
J1808.4-3658 in a quiescent state on March 24, 2001 (Campana et al. 2002,
astro-ph/0206376) can be explained only if this SXT contains a massive neutron
star with a nucleon/hyperon core; a hyperon core with a not too low fraction of
electrons is preferable. Future observations may discriminate between the
various models of hyperon/nucleon dense matter. The thermal emission of SAX
J1808.4-3658 is also sensitive to the models of plasma ionization in the
outermost surface layers and can serve for testing such models.Comment: 12 pages, 5 figures, 4 tables, LaTeX2e with aa.cls v.5.3 (included).
Accepted by A&
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