1,189 research outputs found
Flexploitation: the case of the 2012 Spanish labour market reform
Ronald Janssen of the European Trade Union Confederation argues against the idea that the solution to unemployment lies in more flexible working practices, pointing out that precarious jobs make for a precarious recovery
Prospects for high-resolution microwave spectroscopy of methanol in a Stark-deflected molecular beam
Recently, the extremely sensitive torsion-rotation transitions in methanol
have been used to set a tight constraint on a possible variation of the
proton-to-electron mass ratio over cosmological time scales. In order to
improve this constraint, laboratory data of increased accuracy will be
required. Here, we explore the possibility for performing high-resolution
spectroscopy on methanol in a Stark-deflected molecular beam. We have
calculated the Stark shift of the lower rotational levels in the ground
torsion-vibrational state of CH3OH and CD3OH molecules, and have used this to
simulate trajectories through a typical molecular beam resonance setup.
Furthermore, we have determined the efficiency of non-resonant multi-photon
ionization of methanol molecules using a femtosecond laser pulse. The described
setup is in principle suited to measure microwave transitions in CH3OH at an
accuracy below 10^{-8}
A novel time series approach to bridge coding changes with a consistent solution across causes of death
Revisions of the International Classification of Diseases (ICD) can lead to biases in cause-specific mortality levels and trends. We propose a novel time series approach to bridge ICD coding changes which provides a consistent solution across causes of death. Using a state space model with interventions, we performed time series analysis to cause-proportional mortality for ICD9 and ICD10 in the Netherlands (1979–2010), Canada (1979–2007) and Italy (1990–2007) on chapter level. A constraint was used to keep the sum of cause-specific interventions zero. Comparability ratios (CRs) were estimated and compared to existing bridge coding CRs for Italy and Canada. A significant ICD9 to ICD10 transition occurred among 13 cause of death groups in Italy, 7 in Canada and 3 in the Netherlands. Without the constraint, all-cause mortality after the classification change would be overestimated by 0.4 % (NL), 0.03 % (Canada) and 0.2 %(Italy).ThetimeseriesCRswereinthesamedirectionasthebridgecodingCRsbut deviated more from 1. A smooth corrected trend over the ICD-transition resulted from applying the time series approach. Comparing the time series CRs for Italy (2003), Canada (1999) and the Netherlands (1995) revealed interesting commonalities and dif- ferences. We demonstrated the importance of adding the constraint, the validity of our methodology and its advantages above earlier methods. Applying the method to more specific causes of death and integrating medical content to a larger extent is advocated
A Novel Time Series Approach to Bridge Coding Changes with a Consistent Solution Across Causes of Death
Revisions of the International Classification of Diseases (ICD) can lead to biases in cause-specific mortality levels and trends. We propose a novel time series approach to bridge ICD coding changes which provides a consistent solution across causes of death. Using a state space model with interventions, we performed time series analysis to cause-proportional mortality for ICD9 and ICD10 in the Netherlands (1979–2010), Canada (1979–2007) and Italy (1990–2007) on chapter level. A constraint was used to keep the sum of cause-specific interventions zero. Comparability ratios (CRs) were estimated and compared to existing bridge coding CRs for Italy and Canada. A significant ICD9 to ICD10 transition occurred among 13 cause of death groups in Italy, 7 in Canada and 3 in the Netherlands. Without the constraint, all-cause mortality after the classification change would be overestimated by 0.4 % (NL), 0.03 % (Canada) and 0.2 % (Italy). The time series CRs were in the same direction as the bridge coding CRs but deviated more from 1. A smooth corrected trend over the ICD-transition resulted from applying the time series approach. Comparing the time series CRs for Italy (2003), Canada (1999) and the Netherlands (1995) revealed interesting commonalities and differences. We demonstrated the importance of adding the constraint, the validity of our methodology and its advantages above earlier methods. Applying the method to more specific causes of death and integrating medical content to a larger extent is advocated
On the absorbing-state phase transition in the one-dimensional triplet creation model
We study the lattice reaction diffusion model 3A -> 4A, A -> 0 (``triplet
creation") using numerical simulations and n-site approximations. The
simulation results provide evidence of a discontinuous phase transition at high
diffusion rates. In this regime the order parameter appears to be a
discontinuous function of the creation rate; no evidence of a stable interface
between active and absorbing phases is found. Based on an effective mapping to
a modified compact directed percolation process, shall nevertheless argue that
the transition is continuous, despite the seemingly discontinuous phase
transition suggested by studies of finite systems.Comment: 23 pages, 11 figure
Phase diagram of a probabilistic cellular automaton with three-site interactions
We study a (1+1) dimensional probabilistic cellular automaton that is closely
related to the Domany-Kinzel (DKCA), but in which the update of a given site
depends on the state of {\it three} sites at the previous time step. Thus,
compared with the DKCA, there is an additional parameter, , representing
the probability for a site to be active at time , given that its nearest
neighbors and itself were active at time . We study phase transitions and
critical behavior for the activity {\it and} for damage spreading, using one-
and two-site mean-field approximations, and simulations, for and
. We find evidence for a line of tricritical points in the () parameter space, obtained using a mean-field approximation at pair level.
To construct the phase diagram in simulations we employ the growth-exponent
method in an interface representation. For , the phase diagram is
similar to the DKCA, but the damage spreading transition exhibits a reentrant
phase. For , the growth-exponent method reproduces the two absorbing
states, first and second-order phase transitions, bicritical point, and damage
spreading transition recently identified by Bagnoli {\it et al.} [Phys. Rev.
E{\bf 63}, 046116 (2001)].Comment: 15 pages, 7 figures, submited to PR
Effects of Somatostatin Analogs and Dopamine Agonists on Insulin-Like Growth Factor 2-Induced Insulin Receptor Isoform A Activation by Gastroenteropancreatic Neuroendocrine Tumor Cells
Background: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) express insulin-like growth factor (IGF)-related factors [IGF1, IGF2; insulin receptor (IR)-A, IR-B; IGF-binding protein (IGFBP) 1-3] as well as somatostatin (SSTRs) and dopamine D2 receptors (D2Rs). Objectives: To (1) compare mRNA expression of IGF-related factors in human pancreatic NET (panNET) cell lines with that in human GEP-NETs to evaluate the usefulness of these cells as a model for studying the IGF system in GEP-NETs, (2) determine whether panNET cells produce growth factors that activate IR-A, and (3) investigate whether somatostatin analogs (SSAs) and/or dopamine agonists (DAs) influence the production of these growth factors. Methods: In panNET cells (BON-1 and QGP-1) and GEP-NETs, mRNA expression of IGF-related factors was measured by quantitative real-time PCR. Effects of the SSAs octreotide and pasireotide (PAS), the DA cabergoline (CAB), and the dopastatin BIM-23A760 (all 100 nM) were evaluated at the IGF2 mRNA and protein level (by ELISA) and regarding IR-A bioactivity (by kinase receptor activation assay) in panNET cells. Results: panNET cells and GEP-NETs had comparable expression profiles of IGF-related factors. Especially in BON-1 cells, IGF2 and IR-A were most highly expressed. PAS + CAB inhibited IGF2 (-29.5 ± 4.9%, p < 0.01) and IGFBP3 (-20.0 ± 4.0%, p < 0.01) mRNA expression in BON-1 cells. In BON-1 cells, IGF2 protein secretion was significantly inhibited with BIM-23A760 (-23.7 ± 3.8%). BON-1- but not QGP-1- conditioned medium stimulated IR-A bioactivity. In BON-1 cells, IR-A bioactivity was inhibited by BIM-23A760 and PAS + CAB (-37.8 ± 2.1% and -30.9 ± 4.1%, respectively, p < 0.0001). Conclusions: (1) The BON-1 cell line is a representative model for studying the IGF system in GEP-NETs, (2) BON-1 cells produce growth factors (IGF2) activating IR-A, and (3) combined SSTR and D2R targeting with PAS + CAB and BIM-23A760 suppresses IGF2-induced IR-A activation.</p
Nonequilibrium Phase Transitions in Epidemics and Sandpiles
Nonequilibrium phase transitions between an active and an absorbing state are
found in models of populations, epidemics, autocatalysis, and chemical
reactions on a surface. While absorbing-state phase transitions fall
generically in the DP universality class, this does not preclude other
universality classes, associated with a symmetry or conservation law. An
interesting issue concerns the dynamic critical behavior of models with an
infinite number of absorbing configurations or a long memory. Sandpile models,
the principal example of self-organized criticality (SOC), also exhibit
absorbing- state phase transitions, with SOC corresponding to a particular mode
of forcing the system toward its critical point.Comment: 10 pages; based on invited talk at StatPhys 2
Effects of Somatostatin Analogs and Dopamine Agonists on Insulin-Like Growth Factor 2-Induced Insulin Receptor Isoform A Activation by Gastroenteropancreatic Neuroendocrine Tumor Cells
Background: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) express insulin-like growth factor (IGF)-related factors [IGF1, IGF2; insulin receptor (IR)-A, IR-B; IGF-binding protein (IGFBP) 1-3] as well as somatostatin (SSTRs) and dopamine D2 receptors (D2Rs). Objectives: To (1) compare mRNA expression of IGF-related factors in human pancreatic NET (panNET) cell lines with that in human GEP-NETs to evaluate the usefulness of these cells as a model for studying the IGF system in GEP-NETs, (2) determine whether panNET cells produce growth factors that activate IR-A, and (3) investigate whether somatostatin analogs (SSAs) and/or dopamine agonists (DAs) influence the production of these growth factors. Methods: In panNET cells (BON-1 and QGP-1) and GEP-NETs, mRNA expression of IGF-related factors was measured by quantitative real-time PCR. Effects of the SSAs octreotide and pasireotide (PAS), the DA cabergoline (CAB), and the dopastatin BIM-23A760 (all 100 nM) were evaluated at the IGF2 mRNA and protein level (by ELISA) and regarding IR-A bioactivity (by kinase receptor activation assay) in panNET cells. Results: panNET cells and GEP-NETs had comparable expression profiles of IGF-related factors. Especially in BON-1 cells, IGF2 and IR-A were most highly expressed. PAS + CAB inhibited IGF2 (-29.5 ± 4.9%, p < 0.01) and IGFBP3 (-20.0 ± 4.0%, p < 0.01) mRNA expression in BON-1 cells. In BON-1 cells, IGF2 protein secretion was significantly inhibited with BIM-23A760 (-23.7 ± 3.8%). BON-1- but not QGP-1- conditioned medium stimulated IR-A bioactivity. In BON-1 cells, IR-A bioactivity was inhibited by BIM-23A760 and PAS + CAB (-37.8 ± 2.1% and -30.9 ± 4.1%, respectively, p < 0.0001). Conclusions: (1) The BON-1 cell line is a representative model for studying the IGF system in GEP-NETs, (2) BON-1 cells produce growth factors (IGF2) activating IR-A, and (3) combined SSTR and D2R targeting with PAS + CAB and BIM-23A760 suppresses IGF2-induced IR-A activation.</p
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