5,043 research outputs found
Micro-class mobility: social reproduction in four countries
In the sociological literature on social mobility, the long-standing convention has been to assume that intergenerational reproduction takes one of two forms, either a categorical form that has parents passing on a big-class position to their children, or a gradational form that has parents passing on their socioeconomic standing to their children. These conventional approaches ignore in their own ways the important role that occupations play in transferring advantage and disadvantage from one generation to the next. In log-linear analyses of nationally representative data from the United States, Sweden, Germany, and Japan, we show that (a) occupations are an important conduit for reproduction, (b) the most extreme rigidities in the mobility regime are only revealed when analyses are carried out at the detailed occupational level, and (c) much of what shows up as big-class reproduction in conventional mobility analyses is in fact occupational reproduction in disguise. Although the four countries studied here differ in the extent to which the occupational form has been institutionalized, we show that it is too prominent to ignore in any of these countries. Even in Japan, which has long been regarded as distinctively 'deoccupationalized,' we find evidence of extreme occupational rigidities. These results suggest that an occupational mechanism for reproduction may be a fundamental feature of all contemporary mobility regimes. [author's abstract
Appearance of vertices of infinite order in a model of random trees
We study an equilibrium statistical mechanical model of tree graphs which are
made up of a linear subgraph (the spine) to which leaves are attached. We prove
that the model has two phases, a generic phase where the spine becomes
infinitely long in the thermodynamic limit and all vertices have finite order
and a condensed phase where the spine is finite with probability one and a
single vertex of infinite order appears in the thermodynamic limit. We
calculate the spectral dimension of the graphs in both phases and prove the
existence of a Gibbs measure. We discuss generalizations of this model and the
relationship with models of nongeneric random trees.Comment: 22 pages, 5 figure
Nonlinear resonance in a three-terminal carbon nanotube resonator
The RF-response of a three-terminal carbon nanotube resonator coupled to
RF-transmission lines is studied by means of perturbation theory and direct
numerical integration. We find three distinct oscillatory regimes, including
one regime capable of exhibiting very large hysteresis loops in the frequency
response. Considering a purely capacitive transduction, we derive a set of
algebraic equations which can be used to find the output power (S-parameters)
for a device connected to transmission lines with characteristic impedance
.Comment: 16 pages, 8 figure
Quantum signaling in cavity QED
We consider quantum signaling between two-level quantum systems in a cavity in the perturbative regime of the earliest possible arrival times of the signal. We present two main results: First, we find that, perhaps surprisingly, the analog of amplitude modulated signaling (Alice using her energy eigenstates g,e, as in the Fermi problem) is generally suboptimal for communication, namely, e.g., phase-modulated signaling (Alice using, e.g., {+,-} states) overcomes the quantum noise already at a lower order in perturbation theory. Second, we study the effect of mode truncations that are commonly used in cavity QED on the modeling of the communication between two-level atoms. We show that, on general grounds, namely for causality to be preserved, the UV cutoff must scale at least polynomially with the desired accuracy of the predictions
Dic(9;20)(p13;q11) in childhood acute lymphoblastic leukaemia is related to low cellular resistance to asparaginase, cytarabine and corticosteroids.
To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldDic(9;20)(p13;q11) was first described as a nonrandom chromosome abnormality in B-cell precursor acute lymphoblastic leukaemia (BCP ALL) in the mid 1990s,1, 2 and 71 dic(9;20)-positive cases have since then been reported.3, 4, 5 Approximately 90% of these cases were children or adolescents, with dic(9;20) occurring in about 2% of childhood BCP ALL.6 The recent review by Forestier et al.5 describes that dic(9;20)-leukaemias are of B-cell precursor immunophenotype, never have a high hyperdiploid modal number, show a female predominance, and have a significant age incidence peak at 3 years. Most patients are allocated to non-standard risk treatment arms due to high WBC (median 24 109/l) and a relatively high frequency of CNS disease or other extra-medullary leukaemia (EML) at diagnosis. The prognostic implications of dic(9;20) are to a large extent unknown. A relatively large proportion of the relapses reported in the literature have been extra-medullary, and post-relapse treatment including block therapy has been successful in several patients, as illustrated by a p-EFS of 0.62 and a predicted overall survival of 0.82 at 5 years for the 24 Nordic cases.
The risk and burden of vertebral fractures in Sweden
The aim of this study was to determine the risk and burden of vertebral fractures judged as those coming to clinical attention and as morphometric fractures. Incidence and utility loss were computed from data from Malmo, Sweden. Clinical fractures accounted for 23% of all vertebral deformities in women and for 42% in men. The average 10-year fracture probability for morphometric fractures increased with age in men from 2.9% at the age of 50 years (7.2% in women) to 8.4 at the age of 85 years (26.7% in women). As expected, probabilities increased with decreasing T-score for hip BMD. Cumulative utility loss from a clinical vertebral fracture was substantial and was 50-62% of that due to a hip fracture depending on age. When incidence of fractures in the population was weighted by disutility, all spine fractures accounted for more morbidity than hip fracture up to the age of 75 years. We conclude that vertebral fractures have a major personal and societal impact that needs to be recognised in algorithms for assessment of risk and in health economic strategies for osteoporosis
Normalization factors for magnetic relaxation of small particle systems in non-zero magnetic field
We critically discuss relaxation experiments in magnetic systems that can be
characterized in terms of an energy barrier distribution, showing that proper
normalization of the relaxation data is needed whenever curves corresponding to
different temperatures are to be compared. We show how these normalization
factors can be obtained from experimental data by using the
scaling method without making any assumptions about the nature of the energy
barrier distribution. The validity of the procedure is tested using a
ferrofluid of Fe_3O_4 particles.Comment: 5 pages, 6 eps figures added in April 22, to be published in Phys.
Rev. B 55 (1 April 1997
Numerical Study of Aging in the Generalized Random Energy Model
Magnetizations are introduced to the Generalized Random Energy Model (GREM)
and numerical simulations on ac susceptibility is made for direct comparison
with experiments in glassy materials. Prominent dynamical natures of spin
glasses, {\it i.e.}, {\em memory} effect and {\em reinitialization}, are
reproduced well in the GREM. The existence of many layers causing continuous
transitions is very important for the two natures. Results of experiments in
other glassy materials such as polymers, supercooled glycerol and orientational
glasses, which are contrast to those in spin glasses, are interpreted well by
the Single-layer Random Energy Model.Comment: 8 pages, 9 figures, to be submitted to J. Phys. Soc. Jp
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