1,371 research outputs found
Effects of Disorder on the Pressure-Induced Mott Transition in -BEDT-TTF)Cu[N(CN)]Cl
We present a study of the influence of disorder on the Mott metal-insulator
transition for the organic charge-transfer salt
-(BEDT-TTF)Cu[N(CN)]Cl. To this end, disorder was introduced
into the system in a controlled way by exposing the single crystals to x-ray
irradiation. The crystals were then fine-tuned across the Mott transition by
the application of continuously controllable He-gas pressure at low
temperatures. Measurements of the thermal expansion and resistance show that
the first-order character of the Mott transition prevails for low irradiation
doses achieved by irradiation times up to 100 h. For these crystals with a
moderate degree of disorder, we find a first-order transition line which ends
in a second-order critical endpoint, akin to the pristine crystals. Compared to
the latter, however, we observe a significant reduction of both, the critical
pressure and the critical temperature . This result is consistent
with the theoretically-predicted formation of a soft Coulomb gap in the
presence of strong correlations and small disorder. Furthermore, we
demonstrate, similar to the observation for the pristine sample, that the Mott
transition after 50 h of irradiation is accompanied by sizable lattice effects,
the critical behavior of which can be well described by mean-field theory. Our
results demonstrate that the character of the Mott transition remains
essentially unchanged at a low disorder level. However, after an irradiation
time of 150 h, no clear signatures of a discontinuous metal-insulator
transition could be revealed anymore. These results suggest that, above a
certain disorder level, the metal-insulator transition becomes a smeared
first-order transition with some residual hysteresis.Comment: 20 pages, 7 figures, appeared in the Special Issue "Advances in
Organic Conductors and Superconductors" of Crystal
Break-Up of Aerosol Agglomerates in Highly Turbulent Gas Flow
Agglomerate aerosols in a turbulent flow may be subjected to very high turbulent shear rates which through the generation of lift and drag can overcome the adhesive forces binding the constituents of an agglomerate together and cause it to break-up. This paper presents an analysis of the experimental measurements of the breakup of agglomerates between 0.1-10μm in size, in a turbulent pipe flow followed by an expansion zone with a Reynolds numbers in the range 105 to 107. The analysis shows that even in wall bounded turbulence, the high turbulent shear stresses associated with the small scales of turbulence in the core can be the main source of breakup preceding any break-up that may occur by impaction at the wall. More importantly from these results, a computationally fast and efficient solution is obtained for the General Dynamic Equation (GDE) for agglomerate transport and breakup in highly turbulent flow. Furthermore the solution for the evolution of the aerosol size distribution is consistent with the experimental results. In the turbulent pipe flow section, the agglomerates are exposed continuously to turbulent shear stresses and experience more longer term breakup than in the expansion zone (following the pipe flow) where the exposure time is much less and break-up occurs instantaneously under the action of very high local turbulent shear stresses. The validity of certain approximations made in the model is considered. In particular, the inertia of the agglomerates characterised by a Stokes Number from 0.001 for the smallest particles up to 10 for 10μm particles and the fluctuations of the turbulent shear stresses are important physical phenomena which are not accounted for in the mode
Lymphatic expression of CLEVER-1 in breast cancer and its relationship with lymph node metastasis
BACKGROUND
Mechanisms regulating breast cancer lymph node metastasis are unclear. Staining of CLEVER-1 (common lymphatic endothelial and vascular endothelial receptor-1) in human breast tumors was used, along with in vitro techniques, to assess involvement in the metastatic process.
METHODS
148 sections of primary invasive breast cancers, with 10 yr follow-up, were stained with anti-CLEVER-1. Leukocyte infiltration was assessed, along with involvement of specific subpopulations by staining with CD83 (mature dendritic cells, mDC), CD209 (immature DC, iDC) and CD68 (macrophage, Mϕ). In vitro expression of CLEVER-1 on lymphatic (LEC) and blood endothelial cells (BEC) was examined by flow cytometry.
RESULTS
In vitro results showed that although both endothelial cell types express CLEVER-1, surface expression was only evident on LEC. In tumour sections CLEVER-1 was expressed in blood vessels (BV, 61.4% of samples), lymphatic vessels (LV, 18.2% of samples) and in Mϕ/DCs (82.4% of samples). However, only CLEVER-1 expression in LV was associated with LN metastasis (p = 0.027) and with Mϕ indices (p = 0.021). Although LV CLEVER-1 was associated with LN positivity there was no significant correlation with recurrence or overall survival, BV CLEVER-1 expression was, however, associated with increased risk of recurrence (p = 0.049). The density of inflammatory infiltrate correlated with CLEVER-1 expression in BV (p < 0.001) and LV (p = 0.004).
CONCLUSIONS
The associations between CLEVER-1 expression on endothelial vessels and macrophage/leukocyte infiltration is suggestive of its regulation by inflammatory conditions in breast cancer, most likely by macrophage-associated cytokines. Its upregulation on LV, related surface expression, and association with LN metastasis suggest that it may be an important mediator of tumor cell metastasis to LN
Photon polarization in radiative B decays
We study decay distributions in B -> K pi pi gamma, combining contributions
from several overlapping resonances in a K pi pi mass range near 1400 MeV,
(1^+) K_1(1400), (2^+) K^*_2(1430) and (1^-) K^*(1410). A method is proposed
for using these distributions to determine a photon polarization parameter in
the effective radiative weak Hamiltonian. This parameter is measured through an
up-down asymmetry of the photon direction relative to the K pi pi decay plane.
We calculate a dominant up-down asymmetry of 0.33 +- 0.05 from the K1(1400)
resonance, which can be measured with about 10^8 B B-bar pairs, thus providing
a new test for the Standard Model and a probe for some of its extensions.Comment: 22 pages, 3 figures, version to appear in Phys. Rev.
Facial onset sensory and motor neuronopathy: new cases, cognitive changes and pathophysiology
Purpose of review To improve our clinical understanding of facial onset sensory and motor neuronopathy (FOSMN).
Recent findings We identified 29 new cases and 71 literature cases, resulting in a cohort of 100 patients with FOSMN. During follow-up, cognitive and behavioral changes became apparent in 8 patients, suggesting that changes within the spectrum of frontotemporal dementia (FTD) are a part of the natural history of FOSMN. Another new finding was chorea, seen in 6 cases. Despite reports of autoantibodies, there is no consistent evidence to suggest an autoimmune pathogenesis. Four of 6 autopsies had TAR DNA-binding protein (TDP) 43 pathology. Seven cases had genetic mutations associated with neurodegenerative diseases.
Summary FOSMN is a rare disease with a highly characteristic onset and pattern of disease progression involving initial sensory disturbances, followed by bulbar weakness with a cranial to caudal spread of pathology. Although not conclusive, the balance of evidence suggests that FOSMN is most likely to be a TDP-43 proteinopathy within the amyotrophic lateral sclerosis–FTD spectrum
Anti-Search for the Glueball Candidate f_J(2220) in Two-Photon Interactions
Using 13.3 fb^{-1} of e^+e^- data recorded with the CLEO II and CLEO II.V
detector configurations at CESR, we have searched for f_J(2220) decays to
K^0_{S} K^0_{S} in untagged two-photon interactions. We report an upper limit
on the product of the two-photon partial width and the branching fraction,
Gamma_gamma gamma cdot B (f_J(2220) to K^0_{S} K^0_{S}) of less than 1.1 eV at
the 95% C.L: systematic uncertainties are included. This dataset is four times
larger than that used in the previous CLEO publication.Comment: 10 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, Submitted to PRD (R
Survey Zoroastrians: Online Religious Identification in the Islamic Republic of Iran
This article contributes to the internationalization of survey methodology by discussing a case from a totalitarian state, the Islamic Republic of Iran. In 2020, GAMAAN (The Group for Measuring and Analyzing Attitudes in Iran) conducted an online survey on religion. The survey had 50,000 participants, around 90 percent of whom lived in Iran. This article discusses the result that, after weighting, 8 percent identified as Zoroastrian—many times the number of Zoroastrians as recorded by scholarship on Iranian Zoroastrianism. We dub this phenomenon “Survey Zoroastrianism” and offer an explanation for this finding. After describing the position of Zoroastrianism in modern Iran and adding two further online surveys conducted by GAMAAN in 2022, we discuss the Survey Zoroastrians’ demographics and their religious and political views. The analysis shows that participating in surveys beyond the government's control provided affordances for performing alternative identity aspirations tied to notions of nationalism and civilizational heritage.publishedVersio
Malware detection and prevention system based on multi-stage rules
The continuously rising Internet attacks pose severe challenges to develop an effective Intrusion Detection System (IDS) to detect known and unknown malicious attack. In order to address the problem of detecting known, unknown attacks and identify an attack grouped, the authors provide a new multi stage rules for detecting anomalies in multi-stage rules. The authors used the RIPPER for rule generation, which is capable to create rule sets more quickly and can determine the attack types with smaller numbers of rules. These rules would be efficient to apply for Signature Intrusion Detection System (SIDS) and Anomaly Intrusion Detection System (AIDS)
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