1,063 research outputs found
Construction of Parflux Mark II sediment trap : engineering report
A large, open ocean applicable sediment trap has been
developed at the Woods Hole Oceanographic Institution in order
to assess the fluxes of particles sinking through the deep
water column, under the sponsorship of the National Science
Foundation. PARFLUX Mark II trap, 1978-79 version for PARFLUX
phase 1 program, has been successfully developed and has
gathered much meaningful data. A trap opening is 1.5 m2 and
consists of 94 hexagonal buffer cells with the nominal form
ratio of 2. Sediment particles are concentrated to the
receiving cup located at the bottom of the funnel-shaped trap.
Two types of receiving cups have been developed; a trap with
Type S cup is open at both ends as it sinks to the designated
depth. Twenty-four hours after the deployment the receiving
cup moves into alignment with the funnel to store the
sediment. At the end of deployment a spring mechanism
activated by a quartz oscillator based electrical timer-release
retracts the receiving cup, seals the collected sample and
leave the funnel open at both ends while the trap ascends for
recovery. Type C mechanism is installed with a shutter which
seals the cup during recovery; this type involves a simple
mechanism with less moving parts. Sodium azide/sodium chloride
solution is diffused through a series of membrane filters to
keep the cup contents in an aseptic condition. Since October
1976 to December 1979, we have deployed and recovered 24 traps
successfully along with several moorings as deep as 5,600 m for
as long as 112 days. This reports the engineering detail and
lists the required parts to assist the construction, operation
and maintenance of the PARFLUX Mark II sediment trap.Prepared for the National Science Foundation under Grants
OCE 76-82063 and OCE 77-27004
Asymptotic function for multi-growth surfaces using power-law noise
Numerical simulations are used to investigate the multiaffine exponent
and multi-growth exponent of ballistic deposition growth
for noise obeying a power-law distribution. The simulated values of
are compared with the asymptotic function that is
approximated from the power-law behavior of the distribution of height
differences over time. They are in good agreement for large . The simulated
is found in the range . This implies that large rare events tend to break the KPZ
universality scaling-law at higher order .Comment: 5 pages, 4 figures, to be published in Phys. Rev.
Scaling of impact fragmentation near the critical point
We investigated two-dimensional brittle fragmentation with a flat impact
experimentally, focusing on the low impact energy region near the
fragmentation-critical point. We found that the universality class of
fragmentation transition disagreed with that of percolation. However, the
weighted mean mass of the fragments could be scaled using the pseudo-control
parameter multiplicity. The data for highly fragmented samples included a
cumulative fragment mass distribution that clearly obeyed a power-law. The
exponent of this power-law was 0.5 and it was independent of sample size. The
fragment mass distributions in this regime seemed to collapse into a unified
scaling function using weighted mean fragment mass scaling. We also examined
the behavior of higher order moments of the fragment mass distributions, and
obtained multi-scaling exponents that agreed with those of the simple biased
cascade model.Comment: 6 pages, 6 figure
Multiple Interactions in Two-Photon Collisions
We compute cross sections for events where two pairs of partons scatter off
each other in the same reaction, giving rise to at least 3
high--{\mbox{}} jets. Unlike in {\mbox{}}\ collisions we find
the signal to lie well above the background from higher order QCD processes. If
the usual ``eikonaliztion" assumption is correct, the signal should be readily
observable at LEP2, and might already be detectable in data taken at TRISTAN.Comment: 8 pages, plain LaTeX, 2 figures (not included). A compressed PS file
of the entire paper, including figures, can be obtained via anonymous ftp
from ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-921.ps.
Classification of KPZQ and BDP models by multiaffine analysis
We argue differences between the Kardar-Parisi-Zhang with Quenched disorder
(KPZQ) and the Ballistic Deposition with Power-law noise (BDP) models, using
the multiaffine analysis method. The KPZQ and the BDP models show mono-affinity
and multiaffinity, respectively. This difference results from the different
distribution types of neighbor-height differences in growth paths. Exponential
and power-law distributions are observed in the KPZQ and the BDP, respectively.
In addition, we point out the difference of profiles directly, i.e., although
the surface profiles of both models and the growth path of the BDP model are
rough, the growth path of the KPZQ model is smooth.Comment: 11 pages, 6 figure
Complex interplay between ÎČ-catenin signalling and Notch effectors in intestinal tumorigenesis
International audienceAims The activation of ÎČ-catenin signalling is a key step in intestinal tumorigenesis. Interplay between the ÎČ-catenin and Notch pathways during tumorigenesis has been reported, but the mechanisms involved and the role of Notch remain unclear. Methods Notch status was analysed by studying expression of the Notch effector Hes1 and Notch ligands/receptors in human colorectal cancer (CRC) and mouse models of Apc mutation. A genetic approach was used, deleting the Apc and RBP-J or Atoh1 genes in murine intestine. CRC cell lines were used to analyse the control of Hes1 and Atoh1 by ÎČ-catenin signalling. Results Notch signalling was found to be activated downstream from ÎČ-catenin. It was rapidly induced and maintained throughout tumorigenesis. Hes1 induction was mediated by ÎČ-catenin and resulted from both the induction of the Notch ligand/receptor and Notch-independent control of the Hes1 promoter by ÎČ-catenin. Surprisingly, the strong phenotype of unrestricted proliferation and impaired differentiation induced by acute Apc deletion in the intestine was not rescued by conditional Notch inactivation. Hyperactivation of ÎČ-catenin signalling overrode the forced differention induced by Notch inhibition, through the downregulation of Atoh1, a key secretory determinant factor downstream of Notch. This process involves glycogen synthase kinase 3 ÎČ (GSK3ÎČ) and proteasome-mediated degradation. The restoration of Atoh1 expression in CRC cell lines displaying ÎČ-catenin activation was sufficient to increase goblet cell differentiation, whereas genetic ablation of Atoh1 greatly increased tumour formation in Apc mutant mice. Conclusion Notch signalling is a downstream target of ÎČ-catenin hyperactivation in intestinal tumorigenesis. However, its inhibition had no tumour suppressor effect in the context of acute ÎČ-catenin activation probably due to the downregulation of Atoh1. This finding calls into question the use of Îł-secretase inhibitors for the treatment of CRC and suggests that the restoration of Atoh1 expression in CRC should be considered as a therapeutic approach
Field test of quantum key distribution in the Tokyo QKD Network
A novel secure communication network with quantum key distribution in a
metropolitan area is reported. Different QKD schemes are integrated to
demonstrate secure TV conferencing over a distance of 45km, stable long-term
operation, and application to secure mobile phones.Comment: 21 pages, 19 figure
The Impact of Menthol Cigarettes on Smoking Initiation among Non-Smoking Young Females in Japan
Japan presents an excellent case-study of a nation with low female smoking rates and a negligible menthol market which changed after the cigarette market was opened to foreign competition. Internal tobacco industry documents demonstrate the intent of tobacco manufacturers to increase initiation among young females through development and marketing of menthol brands. Japanese menthol market share rose rapidly from less than 1% in 1980 to 20% in 2008. Menthol brand use was dominated by younger and female smokers, in contrast with non-menthol brands which were used primarily by male smokers. Nationally representative surveys confirm industry surveys of brand use and provide further evidence of the end results of the tobacco industryâs actionsâincreased female smoking in Japan. These findings suggest that female populations may be encouraged to initiate into smoking, particularly in developing nations or where female smoking rates remain low, if the tobacco industry can successfully tailor brands to them. The Japanese experience provides a warning to public health officials who wish to prevent smoking initiation among young females
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