414 research outputs found
Patterns in rational base number systems
Number systems with a rational number as base have gained interest
in recent years. In particular, relations to Mahler's 3/2-problem as well as
the Josephus problem have been established. In the present paper we show that
the patterns of digits in the representations of positive integers in such a
number system are uniformly distributed. We study the sum-of-digits function of
number systems with rational base and use representations w.r.t. this
base to construct normal numbers in base in the spirit of Champernowne. The
main challenge in our proofs comes from the fact that the language of the
representations of integers in these number systems is not context-free. The
intricacy of this language makes it impossible to prove our results along
classical lines. In particular, we use self-affine tiles that are defined in
certain subrings of the ad\'ele ring and Fourier
analysis in . With help of these tools we are able to
reformulate our results as estimation problems for character sums
Future non-linear stability for reflection symmetric solutions of the Einstein-Vlasov system of Bianchi types II and VI
Using the methods developed for the Bianchi I case we have shown that a
boostrap argument is also suitable to treat the future non-linear stability for
reflection symmetric solutions of the Einstein-Vlasov system of Bianchi types
II and VI. These solutions are asymptotic to the Collins-Stewart solution
with dust and the Ellis-MacCallum solution respectively. We have thus
generalized the results obtained by Rendall and Uggla in the case of locally
rotationally symmetric Bianchi II spacetimes to the reflection symmetric case.
However we needed to assume small data. For Bianchi VI there is no
analogous previous result.Comment: 30 page
Using the past to constrain the future: how the palaeorecord can improve estimates of global warming
Climate sensitivity is defined as the change in global mean equilibrium
temperature after a doubling of atmospheric CO2 concentration and provides a
simple measure of global warming. An early estimate of climate sensitivity,
1.5-4.5{\deg}C, has changed little subsequently, including the latest
assessment by the Intergovernmental Panel on Climate Change.
The persistence of such large uncertainties in this simple measure casts
doubt on our understanding of the mechanisms of climate change and our ability
to predict the response of the climate system to future perturbations. This has
motivated continued attempts to constrain the range with climate data, alone or
in conjunction with models. The majority of studies use data from the
instrumental period (post-1850) but recent work has made use of information
about the large climate changes experienced in the geological past.
In this review, we first outline approaches that estimate climate sensitivity
using instrumental climate observations and then summarise attempts to use the
record of climate change on geological timescales. We examine the limitations
of these studies and suggest ways in which the power of the palaeoclimate
record could be better used to reduce uncertainties in our predictions of
climate sensitivity.Comment: The final, definitive version of this paper has been published in
Progress in Physical Geography, 31(5), 2007 by SAGE Publications Ltd, All
rights reserved. \c{opyright} 2007 Edwards, Crucifix and Harriso
Exact Hypersurface-Homogeneous Solutions in Cosmology and Astrophysics
A framework is introduced which explains the existence and similarities of
most exact solutions of the Einstein equations with a wide range of sources for
the class of hypersurface-homogeneous spacetimes which admit a Hamiltonian
formulation. This class includes the spatially homogeneous cosmological models
and the astrophysically interesting static spherically symmetric models as well
as the stationary cylindrically symmetric models. The framework involves
methods for finding and exploiting hidden symmetries and invariant submanifolds
of the Hamiltonian formulation of the field equations. It unifies, simplifies
and extends most known work on hypersurface-homogeneous exact solutions. It is
shown that the same framework is also relevant to gravitational theories with a
similar structure, like Brans-Dicke or higher-dimensional theories.Comment: 41 pages, REVTEX/LaTeX 2.09 file (don't use LaTeX2e !!!) Accepted for
publication in Phys. Rev.
Interventions for female drug-using offenders
Background
This review represents one in a family of three reviews focusing on the effectiveness of interventions in reducing drug use and criminal activity for offenders.
Objectives
To assess the effectiveness of interventions for female drugâusing offenders in reducing criminal activity, or drug use, or both.
Search methods
We searched 12 electronic bibliographic databases up to February 2019.
Selection criteria
We included randomised controlled trials (RCTs).
Data collection and analysis
We used standard methodological procedures expected by Cochrane.
Main results
We included 13 trials with 2560 participants. Interventions were delivered in prison (7/13 studies, 53%) and community (6/13 studies, 47%) settings. The rating of bias was affected by the lack of clear reporting by authors, and we rated many items as 'unclear'.
In two studies (190 participants) collaborative case management in comparison to treatment as usual did not reduce drug use (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.20 to 2.12; 1 study, 77 participants; lowâcertainty evidence), reincarceration at nine months (RR 0.71, 95% CI 0.32 to 1.57; 1 study, 77 participants; lowâcertainty evidence), and number of subsequent arrests at 12 months (RR 1.11, 95% CI 0.83 to 1.49; 1 study, 113 participants; lowâcertainty evidence).
One study (36 participants) comparing buprenorphine to placebo showed no significant reduction in selfâreported drug use at end of treatment (RR 0.57, 95% CI 0.27 to 1.20) and three months (RR 0.58, 95% CI 0.25 to 1.35); very lowâcertainty evidence. No adverse events were reported.
One study (38 participants) comparing interpersonal psychotherapy to a psychoeducational intervention did not find reduction in drug use at three months (RR 0.67, 95% CI 0.30 to 1.50; lowâcertainty evidence).
One study (31 participants) comparing acceptance and commitment therapy (ACT) to a waiting list showed no significant reduction in selfâreported drug use using the Addiction Severity Index (mean difference (MD) â0.04, 95% CI â0.37 to 0.29) and abstinence from drug use at six months (RR 2.89, 95% CI 0.73 to 11.43); lowâcertainty evidence.
One study (314 participants) comparing cognitive behavioural skills to a therapeutic community programme and aftercare showed no significant reduction in selfâreported drug use (RR 0.86, 95% CI 0.58 to 1.27), reâarrest for any type of crime (RR 0.73, 95% CI 0.52 to 1.03); criminal activity (RR 0.80, 95% CI 0.63 to 1.03), or drugârelated crime (RR 0.95, 95% CI 0.68 to 1.32). A significant reduction for arrested (not for parole) violations at six months followâup was significantly in favour of cognitive behavioural skills (RR 0.43, 95% CI 0.25 to 0.77; very lowâcertainty evidence). A second study with 115 participants comparing cognitive behavioural skills to an alternative substance abuse treatment showed no significant reduction in reincarceration at 12 months (RR 0.70, 95% CI 0.43 to 1.12; low certaintyâevidence.
One study (44 participants) comparing cognitive behavioural skills and standard therapy versus treatment as usual showed no significant reduction in Addiction Severity Index (ASI) drug score at three months (MD 0.02, 95% CI â0.05 to 0.09) and six months (MD â0.02, 95% CI â0.09 to 0.05), and incarceration at three months (RR 0.46, 95% CI 0.04 to 4.68) and six months (RR 0.51, 95% CI 0.20 to 1.27); very lowâcertainty evidence.
One study (171 participants) comparing a single computerised intervention versus case management showed no significant reduction in the number of days not using drugs at three months (MD â0.89, 95% CI â4.83 to 3.05; low certaintyâevidence).
One study (116 participants) comparing dialectic behavioural therapy and case management (DBTâCM) versus a health promotion intervention showed no significant reduction at six months followâup in positive drug testing (RR 0.67, 95% CI 0.43 to 1.03), number of people not using marijuana (RR 1.23, 95% CI 0.95 to 1.59), crack (RR 1.00, 95% CI 0.87 to 1.14), cocaine (RR 1.02, 95% CI 0.93 to 1.12), heroin (RR 1.05, 95% CI 0.98 to 1.13), methamphetamine (RR 1.02, 95% CI 0.87 to 1.20), and selfâreported drug use for any drug (RR 1.20, 95% CI 0.92 to 1.56); very lowâcertainty evidence.
One study (211 participants) comparing a therapeutic community programme versus work release showed no significant reduction in marijuana use at six months (RR 1.03, 95% CI 0.19 to 5.65), nor 18 months (RR 1.00, 95% CI 0.07 to 14.45), heroin use at six months (RR 1.59, 95% CI 0.49 to 5.14), nor 18 months (RR 1.92, 95% CI 0.24 to 15.37), crack use at six months (RR 2.07, 95% CI 0.41 to 10.41), nor 18 months (RR 1.64, 95% CI 0.19 to 14.06), cocaine use at six months (RR 1.09, 95% CI 0.79 to 1.50), nor 18 months (RR 0.93, 95% CI 0.64 to 1.35). It also showed no significant reduction in incarceration for drug offences at 18 months (RR 1.45, 95% CI 0.87 to 2.42); with overall very lowâ to lowâcertainty evidence.
One study (511 participants) comparing intensive discharge planning and case management versus prison only showed no significant reduction in use of marijuana (RR 0.79, 95% CI 0.53 to 1.16), hard drugs (RR 1.12, 95% CI 0.88 to 1.43), crack cocaine (RR 1.08, 95% CI 0.75 to 1.54), nor positive hair testing for marijuana (RR 0.75, 95% CI 0.55 to 1.03); it found a significant reduction in arrests (RR 0.19, 95% CI 0.04 to 0.87), but no significant reduction in drug charges (RR 1.07, 95% CI 0.75 to 1.53) nor incarceration (RR 1.09, 95% CI 0.86 to 1.39); moderateâcertainty evidence.
One narrative study summary (211 participants) comparing buprenorphine preâ and postârelease from prison showed no significant reduction in drug use at 12 months postârelease; low certaintyâevidence. No adverse effects were reported.
Authors' conclusions
The studies showed a high degree of heterogeneity for types of comparisons, outcome measures and small samples. Descriptions of treatment modalities are required. On one outcome of arrest (no parole violations), we identified a significant reduction when cognitive behavioural therapy (CBT) was compared to a therapeutic community programme. But for all other outcomes, none of the interventions were effective. Larger trials are required to increase the precision of confidence about the certainty of evidence
Triangulation network of 1929-1944 of the first 1:500 urban map of ValĂšncia
[EN] Triangulation is a surveying method on which earlier maps made were based. Although the origins
of the method can be traced back to the 16th century, it is still used today, with minor changes, to
adjust networks observed with modern geodetic techniques. In this paper we present the geodetic
survey work that was carried out for the primary triangulation network of the first 1:500 urban map of
the city of ValĂšncia (Spain). It spanned from 1929 to 1944 and resulted in 421 maps covering about
174 square kilometres. We focus on four key elements to define the geometric framework of a map:
(1) the geodetic network, (2) the cartographic projection, (3) the baseline measurements, and (4)
the primary triangulation. The paper is based on the interpretation of original documents and
field books recovered from the archives of the ValĂšncia City Council. In order to check the
accuracy and consistency of the survey work, we recomputed all calculations directly from the
field data, following the mathematical procedures of the time. We obtained a set of
transformation parameters to convert the coordinates of 1929 to current coordinates based on
the European Terrestrial Reference System of 1989 (ETRS89). Results showed that the 1929
primary triangulation angles and coordinates are accurate to 8 s of arc and 35 cm respectively,
and that the coordinates transform well into the current reference system with average residuals
of 26 cm across nine control points, demonstrating the high quality of the 1929 work.Villar-Cano, M.; MarquĂ©s-Mateu, Ă.; JimĂ©nez-MartĂnez, MJ. (2020). Triangulation network of 1929-1944 of the first 1:500 urban map of ValĂšncia. Survey Review (Online). 52(373):317-329. https://doi.org/10.1080/00396265.2018.1564599S31732952373Bitelli, G., Cremonini, S., & Gatta, G. (2014). Cartographic heritage: Toward unconventional methods for quantitative analysis of pre-geodetic maps. Journal of Cultural Heritage, 15(2), 183-195. doi:10.1016/j.culher.2013.04.003Blachut, T. J., Chrzanowski, A., & Saastamoinen, J. H. (1979). Urban Surveying and Mapping. doi:10.1007/978-1-4612-6145-2Brinker, R. C., & Minnick, R. (Eds.). (1987). The Surveying Handbook. doi:10.1007/978-1-4757-1188-2Gatta, G. 2010. Valorizzazione di cartografia storica attraverso moderne tecniche geomatiche: recupero metrico, elaborazione e consultazione in ambiente digitale [Valuation of historic cartography using modern geomatics techniques: metric recovering, making and use in digital environment]. Doctoral thesis. Bologna: UniversitĂĄ di Bologna. 295 pages. (In Italian).Gorse, C., Johnston, D., & Pritchard, M. (2012). A Dictionary of Construction, Surveying and Civil Engineering. doi:10.1093/acref/9780199534463.001.0001Hotine, M. (1939). THE RE-TRIANGULATION OF GREAT BRITAIN IVâBASE MEASUREMENT. Empire Survey Review, 5(34), 211-225. doi:10.1179/sre.1939.5.34.211Kahmen, H., & Faig, W. (1988). Surveying. doi:10.1515/9783110845716Leick, A., Rapoport, L., & Tatarnikov, D. (2015). GPS Satellite Surveying. doi:10.1002/9781119018612Murdin, P. (2009). Full Meridian of Glory. doi:10.1007/978-0-387-75534-2Schofield, W., & Breach, M. (2007). Engineering Surveying. doi:10.1201/b12847Seeber, G. (2003). Satellite Geodesy. doi:10.1515/9783110200089Snyder, J. P. (1987). Map projections: A working manual. Professional Paper. doi:10.3133/pp139
Gravitational Lensing at Millimeter Wavelengths
With today's millimeter and submillimeter instruments observers use
gravitational lensing mostly as a tool to boost the sensitivity when observing
distant objects. This is evident through the dominance of gravitationally
lensed objects among those detected in CO rotational lines at z>1. It is also
evident in the use of lensing magnification by galaxy clusters in order to
reach faint submm/mm continuum sources. There are, however, a few cases where
millimeter lines have been directly involved in understanding lensing
configurations. Future mm/submm instruments, such as the ALMA interferometer,
will have both the sensitivity and the angular resolution to allow detailed
observations of gravitational lenses. The almost constant sensitivity to dust
emission over the redshift range z=1-10 means that the likelihood for strong
lensing of dust continuum sources is much higher than for optically selected
sources. A large number of new strong lenses are therefore likely to be
discovered with ALMA, allowing a direct assessment of cosmological parameters
through lens statistics. Combined with an angular resolution <0.1", ALMA will
also be efficient for probing the gravitational potential of galaxy clusters,
where we will be able to study both the sources and the lenses themselves, free
of obscuration and extinction corrections, derive rotation curves for the
lenses, their orientation and, thus, greatly constrain lens models.Comment: 69 pages, Review on quasar lensing. Part of a LNP Topical Volume on
"Dark matter and gravitational lensing", eds. F. Courbin, D. Minniti. To be
published by Springer-Verlag 2002. Paper with full resolution figures can be
found at ftp://oden.oso.chalmers.se/pub/tommy/mmviews.ps.g
Observers and Locality in Everett Quantum Field Theory
A model for measurement in collapse-free nonrelativistic fermionic quantum
field theory is presented. In addition to local propagation and
effectively-local interactions, the model incorporates explicit representations
of localized observers, thus extending an earlier model of entanglement
generation in Everett quantum field theory [M. A. Rubin, Found. Phys. 32,
1495-1523 (2002)]. Transformations of the field operators from the Heisenberg
picture to the Deutsch-Hayden picture, involving fictitious auxiliary fields,
establish the locality of the model. The model is applied to manifestly-local
calculations of the results of measurements, using a type of sudden
approximation and in the limit of massive systems in narrow-wavepacket states.
Detection of the presence of a spin-1/2 system in a given spin state by a
freely-moving two-state observer illustrates the features of the model and the
nonperturbative computational methodology. With the help of perturbation theory
the model is applied to a calculation of the quintessential "nonlocal" quantum
phenomenon, spin correlations in the Einstein-Podolsky-Rosen-Bohm experiment.Comment: Some changes to introduction and discussion sections, typos
corrected, conclusions unchanged. To appear in Foundations of Physic
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