21,219 research outputs found
Substance abuse treatment: what do we know? an economist's perspective
The substance abuse treatment literature has basically dealt with four important questions: 1) Is treatment effective? 2) Are all programs equally effective? 3) why do programs differ in their effectiveness? and 4) which treatments are most cost-effective?. This paper reviews the substance abuse literature around these four questions
A consistent estimator for the binomial distribution in the presence of "incidental parameters": an application to patent data
In this paper a consistent estimator for the Binomial distribution in the presence of incidental parameters, or fixed effects, when the underlying probability is a logistic function is derived. The consistent estimator is obtained from the maximization of a conditional likelihood function in light of Andersen's work. Monte Carlo simulations show its superiority relative to the traditional maximum likelihood estimator with fixed effects also in small samples, particularly when the number of observations in each cross-section, T, is small. Finally, this new estimator is applied to an original dataset that allows the estimation of the probability of obtaining a patent
Dollars and Performance: Treating Alcohol Misuse in Maine
If public funds are allocated efficiently, then an increase in funding should improve the performance of substance abuse treatment programs. In the data used in this paper, performance (measured as abstinence rates) and expenditures per patient are not positively correlated. One explanation is
that funding is endogeneous, i.e. programs treating more difficult patients receive more funding. The data comes from all Maine´s outp/atient drug-free programs that received public funding between 1991 and 1994. After controlling for endogeneity, this paper concludes that the marginal impact of expenditures per patient on abstinence rates is small and statistically insignificantly different from
zero.Publicad
SUBSTANCE ABUSE TREATMENT: WHAT DO WE KNOW? AN ECONOMIST’S PERSPECTIVE
The substance abuse treatment literature has basically dealt with four important questions: 1) Is treatment effective? 2) Are all programs equally effective? 3) why do programs differ in their effectiveness? and 4) which treatments are most cost-effective?. This paper reviews the substance abuse literature around these four questions.
Inelastic quarkonium photoproduction in coherent hadron - hadron interactions at LHC energies
In this paper we study the inelastic quarkonium photoproduction in coherent
interactions. Considering the ultra relativistic hadrons as a
source of photons, we estimate the total ( and ) cross sections and rapidity distributions at
LHC energies. Our results demonstrate that the experimental analysis of this
process can be used to understand the underlying mechanism governing heavy
quarkonium production.Comment: 9 pages, 7 figures, 3 table
Obtaining a class of Type N pure radiation metrics using invariant operators
We develop further the integration procedure in the generalised invariant
formalism, and demonstrate its efficiency by obtaining a class of Petrov type N
pure radiation metrics without any explicit integration, and with comparatively
little detailed calculations. The method is similar to the one exploited by
Edgar and Vickers when deriving the general conformally flat pure radiation
metric. A major addition to the technique is the introduction of non-intrinsic
elements in generalised invariant formalism, which can be exploited to keep
calculations manageable.Comment: This work was presented in July 2004, in the Gr17 meeting held in
Dublin-Irelan
Coherent photon-hadron interactions in pA collisions: Small-x physics after HERA
In this letter we study the photoproduction of heavy quarks and vector mesons
in the coherent proton-nucleus (pA) interactions for RHIC and LHC energies and
analyze if these processes can be used to determine the QCD dynamics at high
energies. The integrated cross section and rapidity distribution are estimated
using the Color Glass Condensate (CGC) formalism. A comparison with the linear
dynamics predictions is also presented. Our results indicate that the nonlinear
dynamics can be proven in those reactions, which are well suited for studing
saturation effects.Comment: 5 pages, 3 figures. Version to be published in Physical Review
Diffractive photoproduction of Z^0 bosons in coherent interactions at CERN-LHC
The exclusive photoproduction at high energies in ,
and collisions is investigate within the color dipole formalism. We
generalize the description of the deeply virtual compton scattering (DVCS)
process, which describe quite well the HERA data, for the production of
bosons and estimate the total cross section for the exclusive process () for different energies, photon virtualities and atomic
numbers. As hadrons at collider energies are a source of Weizs\"{a}cker -
Williams photons, we consider electromagnetic interactions in hadron-hadron
collisions at Tevatron and LHC energies and estimate the rapidity distribution
and total cross section for production in the process.
This is the first estimation for such a process in literature. It can allow us
to study, for instance, the physics of hadronic decays in a clean
environment characterized by two rapidity gaps. Our results indicate that the
experimental analyzes of this process could be feasible in but the physics
scenario for collisions is not promising.Comment: 6 pages, 2 figures, 1 table; The erroneus additional factor of
in the normalization of the cross sections is removed. Figures and table are
update
The QCD Pomeron in Ultraperipheral Heavy Ion Collisions: II. Heavy Quark Production
The heavy quark production in ultraperipheral heavy ion collisions is
investigated, in particular we focus on the results from the coherent
interactions given by the two-photon process. One addresses the heavy quark
total cross sections at photon level considering the saturation model and the
BFKL dynamics in the color dipole picture. The corresponding cross sections at
nuclear level are presented. It is verified that the QCD dynamics implies an
enhancement of the cross section in comparison with previous calculations.Comment: 16 pages, 7 figures. Version to be published in Eur. Phys. J.
- …