54 research outputs found
Are statistical reporting agencies getting it right? Data rationality and business cycle asymmetry
This paper provides new evidence on the rationality of industrial production (IP) and the producer price index (PPI). However, rather than examining preliminary and fully revised data, as is usually the practice, we examine the entire revision history for each data series. Thus, we are able to assess whether earlier releases of data are in any sense "less" rational than laterreleases, for example, and when early releases of data become rational. Our findings suggest that seasonally unadjusted IP and PPI become rational after approximately 3-4 months, while seasonally adjusted versions of these series remain irrational for at least 12 months after initial release. Additionally, we find that there is a clear increase in the volatility of early datareleases during recessions, suggesting that early data are less reliable in tougher economic times. One feature of the approach that we take is that we are able to include revision histories in the information sets used to examine the rationality of a particular release of data. This in turn allows us to assess whether the revision process itself is predictable from its own past, hence possibly leading to rules for the construction of "better" preliminary releases of data. For most of the variables examined, we find evidence of this form of predictability. Another feature of the approach taken in the paper is that we are able to provide evidence suggesting that nonlinearities in economic behavior manifest themselves in the form of nonlinearities in the rationality of early releases of economic data. This is done by separately analyzing expansionary and recessionary economic phases and by allowing for structural breaks. These types of nonlinearities are shown to be prevalent, and in some cases incorrect inferences concerning unbiasedness and efficiency arise when they are not taken account of. For example, seasonally unadjusted IP data become unbiased much more quickly after 1980 than before 1980. Additionally,seasonally adjusted IP data take less time to become efficient during expansions than during recessions.efficiency;real-time data set;unbiasedness
Are statistical reporting agencies getting it right? Data rationality and business cycle asymmetry
This paper provides new evidence on the rationality of industrial production (IP) and the producer price index (PPI). However, rather than examining preliminary and fully revised data, as is usually the practice, we examine the entire revision history for each data series. Thus, we are able to assess whether earlier releases of data are in any sense "less" rational than later
releases, for example, and when early releases of data become rational. Our findings suggest that seasonally unadjusted IP and PPI become rational after approximately 3-4 months, while seasonally adjusted versions of these series remain irrational for at least 12 months after initial release. Additionally, we find that there is a clear increase in the volatility of early data
releases during recessions, suggesting that early data are less reliable in tougher economic times. One feature of the approach that we take is that we are able to include revision histories in the information sets used to examine the rationality of a particular release of data. This in turn allows us to assess whether the revision process itself is predictable from its own past, hence possibly leading to rules for the construction of "better" preliminary releases of data. For most of the variables examined, we find evidence of this form of predictability. Another feature of the approach taken in the paper is that we are able to provide evidence suggesting that nonlinearities in economic behavior manifest themselves in the form of nonlinearities in the rationality of early releases of economic data. This is done by separately analyzing expansionary and recessionary economic phases and by allowing for structural breaks. These types of nonlinearities are shown to be prevalent, and in some cases incorrect inferences concerning unbiasedness and efficiency arise when they are not taken account of. For example, seasonally unadjusted IP data become unbiased much more quickly after 1980 than before 1980. Additionally,
seasonally adjusted IP data take less time to become efficient during expansions than during recessions
A Novel Long Range Spin Chain and Planar N=4 Super Yang-Mills
We probe the long-range spin chain approach to planar N=4 gauge theory at
high loop order. A recently employed hyperbolic spin chain invented by
Inozemtsev is suitable for the SU(2) subsector of the state space up to three
loops, but ceases to exhibit the conjectured thermodynamic scaling properties
at higher orders. We indicate how this may be bypassed while nevertheless
preserving integrability, and suggest the corresponding all-loop asymptotic
Bethe ansatz. We also propose the local part of the all-loop gauge transfer
matrix, leading to conjectures for the asymptotically exact formulae for all
local commuting charges. The ansatz is finally shown to be related to a
standard inhomogeneous spin chain. A comparison of our ansatz to semi-classical
string theory uncovers a detailed, non-perturbative agreement between the
corresponding expressions for the infinite tower of local charge densities.
However, the respective Bethe equations differ slightly, and we end by refining
and elaborating a previously proposed possible explanation for this
disagreement.Comment: 48 pages, 1 figure. v2, further results added: discussion of the
relationship to an inhomogeneous spin chain, normalization in sec 3 unified,
v3: minor mistakes corrected, published versio
Yang-Mills Correlation Functions from Integrable Spin Chains
The relation between the dilatation operator of N=4 Yang-Mills theory and
integrable spin chains makes it possible to compute the one-loop anomalous
dimensions of all operators in the theory. In this paper we show how to apply
the technology of integrable spin chains to the calculation of Yang-Mills
correlation functions by expressing them in terms of matrix elements of spin
operators on the corresponding spin chain. We illustrate this method with
several examples in the SU(2) sector described by the XXX_1/2 chain.Comment: 27 pages, 3 figures, harvma
Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7 fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale
ALK-positive histiocytosis: a new clinicopathologic spectrum highlighting neurologic involvement and responses to ALK inhibition
ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in three infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed clinicopathologic data of 39 cases, including 37 cases with confirmed ALKrearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (seven and twelve from Groups 1B and 2, respectively). Histology included classic xanthogranuloma features in almost one third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated-ERK, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, while CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, ten with neurologic involvement. This study presents the existing clinicopathologic and molecular landscape of ALK-positive histiocytosis, and provides guidance for the clinical management of this emerging histiocytic entity.Molecular tumour pathology - and tumour genetic
Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV
Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values
Search for persistent infection with poliovirus or other enteroviruses in amyotrophic lateral sclerosis-motor neurone disease
A longstanding hypothesis proposes that amyotrophic lateral sclerosis-motor neurone disease (ALS-MND) is a late consequence of subclinical poliovirus (PV) infection. In this study, RNA extracts of CNS tissue from 28 patients with ALS-MND and 7 controls were assayed by nested polymerase chain reaction (PCR) using primers to the 5′-untranslated region (UTR) of the enterovirus (EV) genome which is highly conserved between EVs including PV, echovirus and coxsackie viruses. The integrity of RNA extracted from either archival paraffin-embedded or frozen CNS tissue was assessed by detection of constitutive Ableson tyrosine kinase (ABL) mRNA by PCR. Of 63 tissue samples assayed, 81% () were ABL-positive corresponding to 78% () of the ALS-MND cases and all controls. None of the 27 ALS-MND cases (i.e. 21 ABL+ and 6 ABL−) in which paraffin-embedded tissue was used nor any of the age and sex matched controls were positive for specific PV/EV RNA. Moreover, CNS tissue from 14 different locations obtained from one patient < 2 hrs after death and immediately frozen, showed no evidence of PV/EV at any site by PCR. Disease duration, degree of tissue autolysis and duration of tissue storage were all excluded as factors which may predispose to negative results. The sensitivity of the PV PCR was determined to be 40–400 copies (12.5–125 ag) of synthetic EV RNA transcripts in i gg of cellular RNA and the assay was shown to detect all types of PV and other EVs tested. Thus it seems unlikely that a persistent PV or related EV infection is implicated in ALS-MND unless there has been alteration in the 5′-UTR of the virus genome
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