2,362 research outputs found
Global unions: chasing the dream or building the reality?
This article takes as its theme the global restructuring of capital and its impact on worker organization. It argues for a reassertion of class in any analysis of global solidarity, and assesses the opportunities and barriers to effective global unionization. Rooted in the UK experience, the article analyzes the impact of the European social dimension on trade unions, before taking the discussion into a global dimension. It concludes by suggesting that there are reasons for cautious optimism in terms of solidarity building, despite difficult historical legacies and the common replacement of action with rhetoric
Percolation Transition in the random antiferromagnetic spin-1 chain
We give a physical description in terms of percolation theory of the phase
transition that occurs when the disorder increases in the random
antiferromagnetic spin-1 chain between a gapless phase with topological order
and a random singlet phase. We study the statistical properties of the
percolation clusters by numerical simulations, and we compute exact exponents
characterizing the transition by a real-space renormalization group
calculation.Comment: 9 pages, 4 encapsulated Postscript figures, REVTeX 3.
Chain-Boundary Excitations in the Haldane Phase of 1D Systems
The chain-boundary excitations occurring in the Haldane phaseof
antiferromagnetic spin chains are investigated. The bilinear-biquadratic
hamiltonian is used to study these excitations as a function of the strength of
the biquadratic term, , between . At the AKLT point,
, we show explicitly that these excitations are localized at the
boundaries of the chain on a length scale equal to the correlation length
, and that the on-site magnetization for the first site is
. Applying the density matrixrenormalization group we show that
the chain-boundaryexcitations remain localized at the boundaries for
. As the two critical points are approached the
size of the objects diverges and their amplitude vanishes.Comment: 4 Pages, 4 eps figures. Uses RevTeX 3.0. Submitted to PR
Randomness-driven quantum phase transition in bond-alternating Haldane chain
The effect of bond randomness on the spin-gapped ground state of the spin-1
bond-alternating antiferromagnetic Heisenberg chain is discussed. By using the
loop cluster quantum Monte Carlo method, we investigate the stability of
topological order in terms of the recently proposed twist order parameter [M.
Nakamura and S. Todo: Phys. Rev. Lett. 89 (2002) 077204]. It is observed that
the dimer phases as well as the Haldane phase of the spin-1 Heisenberg chain
are robust against a weak randomness, though the valence-bond-solid-like
topological order in the latter phase is destroyed by introducing a disorder
stronger than the critical value.Comment: 4 pages, 5 figures; minor changes; accepted for publication in J.
Phys. Soc. Jp
A Search for the Near-Infrared Counterpart to GCRT J1745-3009
We present an optical/near-infrared search for a counterpart to the
perplexing radio transient GCRT J1745-3009, a source located ~1 degree from the
Galactic Center. Motivated by some similarities to radio bursts from nearby
ultracool dwarfs, and by a distance upper limit of 70 pc for the emission to
not violate the 1e12 K brightness temperature limit for incoherent radiation,
we searched for a nearby star at the position of GCRT J1745-3009. We found only
a single marginal candidate, limiting the presence of any late-type star to >1
kpc (spectral types earlier than M9), >200 pc (spectral types L and T0-T4), and
>100 pc (spectral types T4-T7), thus severely restricting the possible local
counterparts to GCRT J1745-3009. We also exclude any white dwarf within 1 kpc
or a supergiant star out to the distance of the Galactic Center as possible
counterparts. This implies that GCRT J1745-3009 likely requires a coherent
emission process, although whether or not it reflects a new class of sources is
unclear.Comment: 10 pages, 5 figures. Accepted for publication in the Astrophysical
Journa
A mega-analysis of memory reports from eight peer-reviewed false memory implantation studies
Understanding that suggestive practices can promote false beliefs and false memories forchildhood events is important in many settings (e.g., psychotherapeutic, medical, legal). The generalizability of findings from memory implantation studies has been questioned due to variability in estimates across studies. Such variability is partly due to false memories having been operationalized differently across studies and to differences in memory induction techniques. We explored ways of defining false memory based on memory science and developed a reliable coding system that we applied to reports from eight published implantation studies (N=423). Independent raters coded transcripts using seven criteria: accepting the suggestion, elaboration beyond the suggestion, imagery, coherence, emotion, memory statements, and not rejecting the suggestion. Using this scheme, 30.4% of cases were classified as false memories and another 23% were classified as having accepted the event to some degree. When the suggestion included self-relevant information, an imagination procedure, and was not
accompanied by a photo depicting the event, the memory formation rate was 46.1%. Our research demonstrates a useful procedure for systematically combining data that are not amenable to meta-analysis, and provides the most valid estimate of false memory formation and
associated moderating factors within the implantation literature to date
On the muon neutrino mass
During the runs of the PS 179 experiment at LEAR of CERN, we photographed an
event of antiproton-Ne absorption, with a complete pi+ -> mu+ ->e+ chain. From
the vertex of the reaction a very slow energy pi+ was emitted. The pi+ decays
into a mu+ and subsequently the mu+ decays into a positron. At the first decay
vertex a muon neutrino was emitted and at the second decay vertex an electron
neutrino and a muon antineutrino. Measuring the pion and muon tracks and
applying the momentum and energy conservation and using a classical statistical
interval estimator, we obtained an experimental upper limit for the muon
neutrino mass: m_nu < 2.2 MeV at a 90% confidence level. A statistical analysis
has been performed of the factors contributing to the square value of the
neutrino mass limit.Comment: 18 pages, 5 eps figure
Random Antiferromagnetic Spin-1/2 Chains with Competing Interactions
We study disordered antiferromagnetic spin-1/2 chains with nearest- and
further-neighbor interactions using the real-space renormalization-group
method. We find that the system supports two different phases, depending on the
ratio of the strength between nearest-neighbor and further-neighbor
interactions as well the bond randomness strength. For weak further neighbor
coupling the system is in the familiar random singlet phase, while stronger
further neighbor coupling drives the system to a large spin phase similar to
that found in the study of random antiferromagnetic-ferromagnetic spin chains.
The appearance of the large spin phase in the absence of ferromagnetic coupling
is due to the frustration introduced by further neighboring couplings, and is
unique to the disordered chains.Comment: 11 pages, 7 figure
Competing risks of death in women treated with adjuvant aromatase inhibitors for early breast cancer on NCIC CTG MA.27
Baseline patient and tumor characteristics differentially affected type of death in the MA.17 placebo-controlled letrozole trial where cardiovascular death was not separately identified. The MA.27 trial allowed competing risks analysis of breast cancer (BC), cardiovascular, and other type (OT) of death. MA.27 was a phase III adjuvant breast cancer trial of exemestane versus anastrozole. Effects of baseline patient and tumor characteristics were tested for whether factors were associated with (1) all cause mortality and (2) cause-specific mortality. We also fit step-wise forward cause-specific-adjusted models. 7576 women (median age 64 years; 5417 (72 %) < 70 years and 2159 (28 %) ≥ 70 years) were enrolled and followed for median 4.1 years. The 432 deaths comprised 187 (43 %) BC, 66 (15 %) cardiovascular, and 179 (41 %) OT. Five baseline factors were differentially associated with type of death. Older patients had greater BC (p = 0.03), cardiovascular (p < 0.001), and other types (p < 0.001) of mortality. Patients with pre-existing cardiovascular history had worse cardiovascular mortality (p < 0.001); those with worse ECOG performance status had worse OT mortality (p < 0.001). Patients with T1 tumors (p < 0.001) and progesterone receptor positive had less BC mortality (p < 0.001). Fewer BC deaths occurred with node-negative disease (p < 0.001), estrogen receptor-positive tumors (p = 0.001), and without adjuvant chemotherapy (p = 0.005); worse cardiovascular mortality (p = 0.01), with trastuzumab; worse OT mortality, for non-whites (p = 0.03) and without adjuvant radiotherapy (p = 0.003). Overall, 57 % of deaths in MA.27 AI-treated patients were non-breast cancer related. Baseline patient and tumor characteristics differentially affected type of death with women 70 or older experiencing more non-breast cancer death
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