Portability of social benefits across professions and countries is an increasing concern for individuals and policy makers. Lacking or incomplete transfers of acquired social rights are feared to ...negatively impact individual labor market decisions as well as capacity to address social risks with consequences for economic and social outcomes. The paper gives a fresh and provocative look on the international perspective of the topic that has so far been dominated by social policy lawyers working within the framework of bilateral agreements; the input by economists has been very limited. It offers an analytical framework for portability analysis that suggests separating the risk pooling, (implicit or actual) pre-funding, and redistributive elements in the benefit design, and explores the proposed alternative approach for pensions and health care benefits. This promising approach may serve both as a substitute and complement to bi- and multilateral agreements.
We present data on charged kaons (K±) and ϕ mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K− and ϕ mesons in central heavy-ion collisions below a kinetic beam ...energy of 10A GeV. The ϕ/K− multiplicity ratio is found to be surprisingly high with a value of 0.52±0.16 and shows no dependence on the centrality of the collision. Consequently, the different slopes of the K+ and K− transverse-mass spectra can be explained solely by feed-down, which substantially softens the spectra of K− mesons. Hence, in contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freeze-out temperatures of K+ and K− mesons caused by different couplings to baryons.
.
The centrality determination for Au + Au collisions at 1.23
A
GeV, as measured with HADES at the GSI-SIS18, is described. In order to extract collision geometry related quantities, such as the ...average impact parameter or number of participating nucleons, a Glauber Monte Carlo approach is employed. For the application of this model to collisions at this relatively low centre-of-mass energy of
s
NN
=
2
.
42
GeV special investigations were performed. As a result a well defined procedure to determine centrality classes for ongoing analyses of heavy-ion data is established.
Employing the Bonn–Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction p(3.5 GeV)+p→pK+Λ. This reaction might contain information about the kaonic cluster ...“ppK−” (with quantum numbers JP=0− and total isospin I=1/2) via its decay into pΛ. Due to interference effects in our coherent description of the data, a hypothetical K‾NN (or, specifically “ppK−”) cluster signal need not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectrum like pΛ. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a K‾NN cluster. At a confidence level of CLs=95% such a cluster cannot contribute more than 2–12% to the total cross section with a pK+Λ final state, which translates into a production cross-section between 0.7 μb and 4.2 μb, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process.
We present the first observation of K^{-} and ϕ absorption within nuclear matter by means of π^{-}-induced reactions on C and W targets at an incident beam momentum of 1.7 GeV/c studied with HADES ...at SIS18/GSI. The double ratio (K^{-}/K^{+})_{W}/(K^{-}/K^{+})_{C} is found to be 0.319±0.009(stat)_{-0.012}^{+0.014}(syst) indicating a larger absorption of K^{-} in heavier targets as compared to lighter ones. The measured ϕ/K^{-} ratios in π^{-}+C and π^{-}+W reactions within the HADES acceptance are found to be equal to 0.55±0.04(stat)_{-0.07}^{+0.06}(syst) and to 0.63±0.06(stat)_{-0.11}^{+0.11}(syst), respectively. The similar ratios measured in the two different reactions demonstrate for the first time experimentally that the dynamics of the ϕ meson in nuclear medium is strongly coupled to the K^{-} dynamics. The large difference in the ϕ production off C and W nuclei is discussed in terms of a strong ϕN in-medium coupling. These results are relevant for the description of heavy-ion collisions and the structure of neutron stars.
The high-acceptance dielectron spectrometer HADES Agakichiev, G.; Alvarez-Pol, H.; Balanda, A. ...
European physical journal. A, Hadrons and nuclei,
08/2009, Letnik:
41, Številka:
2
Journal Article
Recenzirano
Odprti dostop
HADES is a versatile magnetic spectrometer aimed at studying dielectron production in pion, proton and heavy-ion-induced collisions. Its main features include a ring imaging gas Cherenkov detector ...for electron-hadron discrimination, a tracking system consisting of a set of 6 superconducting coils producing a toroidal field and drift chambers and a multiplicity and electron trigger array for additional electron-hadron discrimination and event characterization. A two-stage trigger system enhances events containing electrons. The physics program is focused on the investigation of hadron properties in nuclei and in the hot and dense hadronic matter. The detector system is characterized by an 85% azimuthal coverage over a polar angle interval from 18
°
to 85
°
, a single electron efficiency of 50% and a vector meson mass resolution of 2.5%. Identification of pions, kaons and protons is achieved combining time-of-flight and energy loss measurements over a large momentum range ( 0.1 <
p
< 1.0 GeV/
c
. This paper describes the main features and the performance of the detector system.
High-precision measurements of flow coefficients
v
n
(
n
=
1
-
4
) for protons, deuterons and tritons relative to the first-order spectator plane have been performed in Au+Au collisions at
s
NN
=
2.4
... GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at the SIS18/GSI. Flow coefficients are studied as a function of transverse momentum
p
t
and rapidity
y
cm
over a large region of phase-space and for several classes of collision centrality. A clear mass hierarchy, as expected by relativistic hydrodynamics, is found for the slope of
v
1
,
d
v
1
/
d
y
′
|
y
′
=
0
where
y
′
is the scaled rapidity, and for
v
2
at mid-rapidity. Scaling with the number of nucleons is observed for the
p
t
dependence of
v
2
and
v
4
at mid-rapidity, which is indicative for nuclear coalescence as the main process responsible for light nuclei formation.
v
2
is found to scale with the initial eccentricity
⟨
ϵ
2
⟩
, while
v
4
scales with
⟨
ϵ
2
⟩
2
and
⟨
ϵ
4
⟩
. The multi-differential high-precision data on
v
1
,
v
2
,
v
3
, and
v
4
provides important constraints on the equation-of-state of compressed baryonic matter.
We investigate identical pion HBT intensity interferometry in central Au+Au collisions at 1.23A GeV. High-statistics π−π− and π+π+ data are measured with HADES at SIS18/GSI. The radius parameters, ...derived from the correlation function depending on relative momenta in the longitudinally comoving system and parametrized as three-dimensional Gaussian distribution, are studied as function of transverse momentum. A substantial charge-sign difference of the source radii is found, particularly pronounced at low transverse momentum. The extracted source parameters agree well with a smooth extrapolation of the center-of-mass energy dependence established at higher energies, extending the corresponding excitation functions down towards a very low energy.
The stock of migrants living outside their countries of origin may appear small, amounting to some 3% of the world population (United Nations Population Fund 2014). But this represents more than 200 ...million people, and this share has been (re-)increasing since the 1970s. The underlying flows are substantially higher and less is known about them. Therefore, a substantial number of individuals are spending at least part of their lives outside their own countries' borders, mostly working but also in retirement. The potential for international mobility may be even higher, as migration is a highly regulated phenomenon, mainly governed by immigration laws in receiving countries that effectively prohibit migration in many directions and may discourage it in many other cases.
China's pension system Dorfman, Mark C; Holzmann, Robert; O’Keefe, Philip ...
2012., 2013, 02-26-2013, 2013-02-27, 2012-12-15, 20120101
eBook, Book
Odprti dostop
China is at a critical juncture in its economic transition. A comprehensive reform of its pension and social security systems is an essential element of a strategy aimed toward achieving a harmonious ...society and sustainable development. Among policy makers, a widely held view is that the approach to pension provision and reform efforts piloted over the last 10-15 years is insufficient to enable China's economy and population to realize its development objectives in the years ahead. This volume suggests a national pension system that no longer distinguishes along urban and rural locational or hukou lines yet takes account of the diverse nature of employment relations and capacity of individuals to make contributions. This volume is organized as follows: the main text outlines this vision, focusing on summarizing the key features of a proposed long-term pension system. It first examines key trends motivating the need for reform then outlines the proposed three-pillar design and the rationale behind the design choices. It then moves on to examine financing options. The text continues by discussing institutional reform issues, and the final section concludes. The six appendixes provide additional analytical detail supporting the findings in the main text. The pension system design can play an important role in supporting or constraining such economic and demographic transitions: 1) fragmentation and lack of portability of rights hinder labor market efficiency and contribute to coverage gaps; 2) multiple schemes for salaried workers, civil servants, and, in some areas, migrants similarly impact labor markets; 3) legacy costs that are largely financed through current pension contributions weaken incentives for compliance and accurate wage reporting; 4) very limited risk pooling and interurban resource transfers limit the insurance function of the urban pension system and create spatial disparities in old-age income protection; 5) low retirement ages affect incentives and benefits and undermine fiscal sustainability; and 6) relatively low returns on individual accounts result in replacement rates significantly less than anticipated while at the macro level, are likely to inhibit wider efforts to stimulate higher domestic consumption.
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