20,688 research outputs found
A multiwavelength study of massive star-forming region IRAS 22506+5944
We present a multi-line study of the massive star-forming region IRAS
22506+5944. A new 6.7 GHz methanol maser was detected. 12CO, 13CO, C18O and
HCO+ J = 1-0 transition observations reveal a star formation complex consisting
mainly of two cores. The dominant core has a mass of more than 200 solar mass,
while another one only about 35 solar mass. Both cores are obviously at
different evolutionary stages. A 12CO energetic bipolar outflow was detected
with an outflow mass of about 15 solar mass.Comment: 9 pages, 4 figure
Beyond Keywords and Relevance: A Personalized Ad Retrieval Framework in E-Commerce Sponsored Search
On most sponsored search platforms, advertisers bid on some keywords for
their advertisements (ads). Given a search request, ad retrieval module
rewrites the query into bidding keywords, and uses these keywords as keys to
select Top N ads through inverted indexes. In this way, an ad will not be
retrieved even if queries are related when the advertiser does not bid on
corresponding keywords. Moreover, most ad retrieval approaches regard rewriting
and ad-selecting as two separated tasks, and focus on boosting relevance
between search queries and ads. Recently, in e-commerce sponsored search more
and more personalized information has been introduced, such as user profiles,
long-time and real-time clicks. Personalized information makes ad retrieval
able to employ more elements (e.g. real-time clicks) as search signals and
retrieval keys, however it makes ad retrieval more difficult to measure ads
retrieved through different signals. To address these problems, we propose a
novel ad retrieval framework beyond keywords and relevance in e-commerce
sponsored search. Firstly, we employ historical ad click data to initialize a
hierarchical network representing signals, keys and ads, in which personalized
information is introduced. Then we train a model on top of the hierarchical
network by learning the weights of edges. Finally we select the best edges
according to the model, boosting RPM/CTR. Experimental results on our
e-commerce platform demonstrate that our ad retrieval framework achieves good
performance
Optical Susceptibilities of Polymers: Current-Current versus Dipole-Dipole Correlation
The static current operator leads to definitional zero frequency divergence
and unphysical results in studying nonlinear optical susceptibilities of
polymers. A well-defined dipole-dipole correlation is superior to the
complicated current-current correlation to solve this problem. As illustrative
examples, optical susceptibilities under both SSH and TLM models of
trans-(CH)_x are studied. New analytical results are obtained. The reasons of
previous improper results are analyzed
Submillimeter/millimeter observations of the high-mass star forming region IRAS 22506+5944
The mapping observations of CO , CO , CO and
CO lines in the direction of IRAS 22506+5944 have been made. The
results show that the cores in the transition lines have a similar
morphology to those in the transition lines. Bipolar molecular outflows
are verified. The prior IRAS 22506+5944 observations indicated that two IRAS
sources and three HO masers were located close to the peak position of
the core. One of the IRAS sources may be the driving source of the outflows. In
addition, the HO masers may occur in relatively warm environments. The
parameters of the dense core and outflow, obtained by the LTE method, indicate
that IRAS 22506+5944 is a high-mass star formation region.Comment: 8 pages, 4 figures, published in RA
Hardy's Paradox for High-Dimensional Systems: Beyond Hardy's Limit
Hardy's proof is considered the simplest proof of nonlocality. Here we
introduce an equally simple proof that (i) has Hardy's as a particular case,
(ii) shows that the probability of nonlocal events grows with the dimension of
the local systems, and (iii) is always equivalent to the violation of a tight
Bell inequality.Comment: REVTeX4, 5 pages, 1 figure. Typo in Eq. (17) corrected. Ref. [5]
complete
Beyond Gisin's Theorem and its Applications: Violation of Local Realism by Two-Party Einstein-Podolsky-Rosen Steering
We demonstrate here that for a given mixed multi-qubit state if there are at
least two observers for whom mutual Einstein-Podolsky-Rosen steering is
possible, i.e. each observer is able to steer the other qubits into two
different pure states by spontaneous collapses due to von Neumann type
measurements on his/her qubit, then nonexistence of local realistic models is
fully equivalent to quantum entanglement (this is not so without this
condition). This result leads to an enhanced version of Gisin's theorem
(originally: all pure entangled states violate local realism). Local realism is
violated by all mixed states with the above steering property. The new class of
states allows one e.g. to perform three party secret sharing with just pairs of
entangled qubits, instead of three qubit entanglements (which are currently
available with low fidelity). This significantly increases the feasibility of
having high performance versions of such protocols. Finally, we discuss some
possible applications.Comment: 9 pages, 1 figur
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