10,293 research outputs found
Time and Spacetime: The Crystallizing Block Universe
The nature of the future is completely different from the nature of the past.
When quantum effects are significant, the future shows all the signs of quantum
weirdness, including duality, uncertainty, and entanglement. With the passage
of time, after the time-irreversible process of state-vector reduction has
taken place, the past emerges, with the previous quantum uncertainty replaced
by the classical certainty of definite particle identities and states. The
present time is where this transition largely takes place, but the process does
not take place uniformly: Evidence from delayed choice and related experiments
shows that isolated patches of quantum indeterminacy remain, and that their
transition from probability to certainty only takes place later. Thus, when
quantum effects are significant, the picture of a classical Evolving Block
Universe (`EBU') cedes place to one of a Crystallizing Block Universe (`CBU'),
which reflects this quantum transition from indeterminacy to certainty, while
nevertheless resembling the EBU on large enough scales.Comment: 25 Pages. 3 figure
Estimating sufficient reductions of the predictors in abundant high-dimensional regressions
We study the asymptotic behavior of a class of methods for sufficient
dimension reduction in high-dimension regressions, as the sample size and
number of predictors grow in various alignments. It is demonstrated that these
methods are consistent in a variety of settings, particularly in abundant
regressions where most predictors contribute some information on the response,
and oracle rates are possible. Simulation results are presented to support the
theoretical conclusion.Comment: Published in at http://dx.doi.org/10.1214/11-AOS962 the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org
“I\u27ll do whatever as long as you keep telling me that I’m important”: A case study illustrating the link between adolescent dating violence and sex trafficking victimization
Background: Approximately 10% of U.S. high school-attending youth are physically abused by a dating partner each year. Many sequelae of dating violence have been documented, but the dating violence literature is lacking information about commercial sexual exploitation as a possible outcome of an abusive dating relationship. Conversely, scholarship on sex trafficking victimization has documented that some girls are enticed into sex work by exploitative partners who initially pretend to be dating partners, but the research lacks specificity about why and how the girls become vulnerable to these destructive relationships. This case series chronicles the experiences of four women who were commercially sexually exploited in the U.S. as minors, identifies common themes cross their narratives, and organizes these themes into a proposed framework for understanding a possible pathway from safety to unsafe dating to sex trafficking victimization.
Methods: We conducted in-depth qualitative interviews with four adult women who had firsthand experience as victims of domestic minor sex trafficking. Participants were recruited through an organization that serves sex trafficking survivors. A constructivist grounded approach was used for data analysis. Participants’ narratives are presented, as well as illustrative quotes that typify each of the primary themes identified.
Results: There were six primary themes that emerged from the cases’ narratives. Factors that made girls vulnerable to entering into abusive dating relationships and subsequently to experiences as sex trafficked minors included: (1) feeling physically unattractive and unimportant; (2) lacking examples of healthy relationships; (3) experiencing sexual abuse that caused subsequent dissociation and emotional debilitation; (4) being flattered by romantic gestures early in an abusive dating relationship and becoming emotionally attached; (5) gaining confidence from dating someone with higher social status; and (6) experiencing short-term satisfaction from out-earning other sex workers. Secondary themes that merit further investigation included having conflicts with guardians, engaging in criminal behavior at the request of their dating partner, and developing substance dependence that made it difficult to exit sex work.
Discussion: Findings support the conclusions that one pathway into commercial sexual exploitation for minors is via dating partners, and that some minors are motivated to engage in sex work out of devotion to their dating partners rather than fear of violent retribution. A proposed framework for understanding how youth become vulnerable to sexual exploitation by a dating partner includes pre-dating, early phase dating, and late phase dating factors. Some pre-dating factors, for example, include feeling insecure, being bullied by peers, and having conflict with a guardian. Early phase dating factors include being impressed by the high social status of a new love interest and romantic gestures. Late phase dating factors include engaging in criminal activity to please the dating partner, and being physically, sexually, financially and emotionally abused. Additional empirical research that replicates and expands the proposed framework is encouraged, with the long-term objective of improving both dating violence and sexual exploitation prevention initiative
Equity Returns and Business Cycles in Small Open Economies
This is the first paper in the literature to match key business cycle moments and long-run equity returns in a small open economy with production. These results are achieved by introducing three modications to a standard real business cycle model: (1) borrowing and lending costs are imposed to increase the volatility of the intertemporal marginal rate of substitution; (2) investment adjustment costs are assumed to make equity returns more volatile; and (3) GHH preferences are employed to smooth consumption. We also decompose the contributions of productivity, the world interest rate, and government expenditure shocks to the equity premium. Our results are based on data from Argentina, Brazil, and Chile.Asset Pricing; Equity Returns; Dynamic Stochastic General Equilibrium Model; Real Business Cycle; Small Open Economy.
Feminism, Abortion and Disability: irreconcilable differences?
There has been considerable discussion of the political allegiance between the feminist and disability movements, but the question of abortion remains a thorny one. Disability rights advocates have been keen to demonstrate that it is possible to believe in a woman's right to sovereignty over the body and, yet, be opposed to the selective abortion of an impaired foetus – describing the latter as a form of 'weak' eugenics.
The aim of this paper is to show that whilst there may be some points of agreement between the feminist and disability movements on the question of abortion, there exist fundamental and irreconcilable differences
Lattice-Boltzmann Method for Non-Newtonian Fluid Flows
We study an ad hoc extension of the Lattice-Boltzmann method that allows the
simulation of non-Newtonian fluids described by generalized Newtonian models.
We extensively test the accuracy of the method for the case of shear-thinning
and shear-thickening truncated power-law fluids in the parallel plate geometry,
and show that the relative error compared to analytical solutions decays
approximately linear with the lattice resolution. Finally, we also tested the
method in the reentrant-flow geometry, in which the shear-rate is no-longer a
scalar and the presence of two singular points requires high accuracy in order
to obtain satisfactory resolution in the local stress near these points. In
this geometry, we also found excellent agreement with the solutions obtained by
standard finite-element methods, and the agreement improves with higher lattice
resolution
A Phase Space Approach to Gravitational Enropy
We examine the definition S = ln Omega as a candidate "gravitational entropy"
function. We calculate its behavior for gravitationl and density perturbations
in closed, open and flat cosmologies and find that in all cases it increases
monotonically. Using the formalism to calculate the gravitational entropy
produced during inflation gives the canonical answer. We compare the behavior
of S with the behavior of the square of the Weyl tensor. Applying the formalism
to black holes has proven more problematical.Comment: Talk delivered at South African Relativistic Cosmology Symposium, Feb
1999. Some new results over Rothman and Anninos 97. To appear in GRG, 17
page
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Coming of age in L3 initial stages transfer models: deriving developmental predictions and looking towards the future
Aims: Over the past decade in particular, formal linguistic work within L3 acquisition has concentrated on hypothesizing and empirically determining the source of transfer from previous languages—L1, L2 or both—in L3 grammatical representations. In view of the progressive concern with more advanced stages, we aim to show that focusing on L3 initial stages should be one continued priority of the field, even—or especially—if the field is ready to shift towards modeling L3 development and ultimate attainment.
Approach: We argue that L3 learnability is significantly impacted by initial stages transfer, as such forms the basis of the initial L3 interlanguage. To illustrate our point, the insights from studies using initial and intermediary stages L3 data are discussed in light of developmental predictions that derive from the initial stages models.
Conclusions: Despite a shared desire to understand the process of L3 acquisition in whole, inclusive of offering developmental L3 theories, we argue that the field does not yet have—although is ever closer to—the data basis needed to effectively do so.
Originality: This article seeks to convince the readership for the need of conservatism in L3 acquisition theory building, whereby offering a framework on how and why we can most effectively build on the accumulated knowledge of the L3 initial stages in order to make significant, steady progress.
Significance: The arguments exposed here are meant to provide an epistemological base for a tenable framework of formal approaches to L3 interlanguage development and, eventually, ultimate attainment
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