4,698 research outputs found
Resolving Boosted Jets with XCone
We show how the recently proposed XCone jet algorithm smoothly interpolates
between resolved and boosted kinematics. When using standard jet algorithms to
reconstruct the decays of hadronic resonances like top quarks and Higgs bosons,
one typically needs separate analysis strategies to handle the resolved regime
of well-separated jets and the boosted regime of fat jets with substructure.
XCone, by contrast, is an exclusive cone jet algorithm that always returns a
fixed number of jets, so jet regions remain resolved even when (sub)jets are
overlapping in the boosted regime. In this paper, we perform three LHC case
studies---dijet resonances, Higgs decays to bottom quarks, and all-hadronic top
pairs---that demonstrate the physics applications of XCone over a wide
kinematic range.Comment: 36 pages, 25 figures, 1 table; v2: references added; v3: discussion
added and new appendix B to match JHEP versio
In Honor of Matthew Rabin: Winner of the John Bates Clark Medal
Although there is some evidence that Matthew Rabin existed before 1990, we had the pleasure of discovering him for ourselves when, in the early 1990s, he sent each of us a copy of his manuscript "Incorporating Fairness into Game Theory and Economics" [2]. Matthew was, at this time, an assistant professor in Berkeley's economics department, having recently finished his graduate training at MIT. The paper was remarkable in many ways, and it induced us both to call around and ask: "Who is this guy Rabin?" Now, just a decade later, we find ourselves writing an article in honor of his winning the John Bates Clark award. So, who is this guy
Anomalies: Ultimatums, Dictators and Manners
Economics can be distinguished from other social sciences by the belief that
most (all?) behavior can be explained by assuming that agents have stable,
well-defined preferences and make rational choices consistent with those preferences
in markets that (eventually) clear. An empirical result qualifies as an
anomaly if it is difficult to "rationalize" or if implausible assumptions are
necessary to explain it within the paradigm. This column will resume, after a
long rest, the investigation of such anomalies
Generalized Arcsine Law and Stable Law in an Infinite Measure Dynamical System
Limit theorems for the time average of some observation functions in an
infinite measure dynamical system are studied. It is known that intermittent
phenomena, such as the Rayleigh-Benard convection and Belousov-Zhabotinsky
reaction, are described by infinite measure dynamical systems.We show that the
time average of the observation function which is not the function,
whose average with respect to the invariant measure is finite, converges to
the generalized arcsine distribution. This result leads to the novel view that
the correlation function is intrinsically random and does not decay. Moreover,
it is also numerically shown that the time average of the observation function
converges to the stable distribution when the observation function has the
infinite mean.Comment: 8 pages, 8 figure
A Borel-Cantelli lemma for intermittent interval maps
We consider intermittent maps T of the interval, with an absolutely
continuous invariant probability measure \mu. Kim showed that there exists a
sequence of intervals A_n such that \sum \mu(A_n)=\infty, but \{A_n\} does not
satisfy the dynamical Borel-Cantelli lemma, i.e., for almost every x, the set
\{n : T^n(x)\in A_n\} is finite. If \sum \Leb(A_n)=\infty, we prove that
\{A_n\} satisfies the Borel-Cantelli lemma. Our results apply in particular to
some maps T whose correlations are not summable.Comment: 7 page
Dynamic Phase Transitions in Cell Spreading
We monitored isotropic spreading of mouse embryonic fibroblasts on
fibronectin-coated substrates. Cell adhesion area versus time was measured via
total internal reflection fluorescence microscopy. Spreading proceeds in
well-defined phases. We found a power-law area growth with distinct exponents
a_i in three sequential phases, which we denote basal (a_1=0.4+-0.2), continous
(a_2=1.6+-0.9) and contractile (a_3=0.3+-0.2) spreading. High resolution
differential interference contrast microscopy was used to characterize local
membrane dynamics at the spreading front. Fourier power spectra of membrane
velocity reveal the sudden development of periodic membrane retractions at the
transition from continous to contractile spreading. We propose that the
classification of cell spreading into phases with distinct functional
characteristics and protein activity patterns serves as a paradigm for a
general program of a phase classification of cellular phenotype. Biological
variability is drastically reduced when only the corresponding phases are used
for comparison across species/different cell lines.Comment: 4 pages, 5 figure
Mise en évidence de deux espèces jumelles sympatriques du genre Hylomyscus dans le nord-est du Gabon
Prostaglandins in breast cancer: relationship to disease stage and hormone status.
Tissue prostaglandin (PG) content and production by human breast cancers were measured in 24 human mammary carcinoma specimens. The 5 compounds studied were PGE1, PGE2, PGF2 alpha, 6-keto-PGF1 alpha, and TXB2. The tissue content of all 5 compounds was higher in neoplastic tissue in comparison with the paired noncancerous breast tissue. However, microsomal PG synthetase activity in vitro in noncancerous and neoplastic breast tissue was comparable. Increased thromboxane formation was associated with three clinical variables--tumour size, axillary lymph node metastases and distant metastasis. A lesion negative for either oestrogen or progesterone receptor content tended to produce more TXB2 but lower PGE2 and 6-keto-PGF1 alpha. Results obtained in this pilot study may provide clues as to what direction future larger studies could take in the search for reliable prognostic indicators for breast cancer
An in vivo evaluation of Brilliant Blue G in animals and humans
Background/Aims: To evaluate the retinal toxicity of Brilliant Blue G (BBG) following intravitreal injection in rat eyes and examine the biocompatibility and the staining properties in humans.Methods: BBG was injected into the 11 rat eyes to evaluate toxic effects with balanced salt solution (BSS) serving as control. Retinal toxicity was assessed by retinal ganglion cell (RGC) counts and by light microscopy 7 days later. In addition, BBG was applied during vitrectomy for macular hole (MH) (n = 15) or epiretinal membranes (ERM) (n = 3) in a prospective, non-comparative consecutive series of patients. Before and after surgery, all patients underwent a complete clinical examination including measurement of best corrected visual acuity (VA) and intraocular pressure, perimetry, fundus photography and optical coherence tomography. Patients were seen 1 day before surgery and then in approximately four weeks intervals.Results: No significant reduction in RGC numbers and no morphological alterations were noted. A sufficient staining of the internal limiting membrane (ILM) was seen in patients with MH, while the staining pattern in ERM cases was patchy, indicating that parts of the ILM were peeled off along with the ERM in a variable extent. All MHs could be closed successfully. VA improved in 10 eyes (56%; 8/15 MH patients, 2/3 ERM patients), was unchanged in four eyes (22%; all MH patients) and was reduced in four eyes (22%; 3/15 MH, 1/3 ERM). No toxic effects attributable to the dye were noted during patient follow-up. The ultrastructure of tissue harvested during surgery was unremarkable.Conclusion: Brilliant Blue provides a sufficient and selective staining of the ILM. No retinal toxicity or adverse effects related to the dye were observed in animal and human studies. The long-term safety of this novel dye will have to be evaluated in larger patient series and a longer follow-up
Cash by any other name? Evidence on labeling from the UK Winter Fuel Payment
Government transfers to individuals are often given labels indicating that they are designed to support the consumption of particular goods. Standard economic theory implies that the labeling of cash transfers or cash-equivalents should have no effect on spending patterns. We study the UK Winter Fuel Payment, a cash transfer to older households. Our empirical strategy nests a regression discontinuity design within an Engel curve framework. We find robust evidence of a behavioral effect of labeling. On average households spend 47% of the WFP on fuel. If the payment were treated as cash, we would expect households to spend 3% of the payment on fuel. © 2014 Elsevier B.V
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