2,595 research outputs found
The Transition State in a Noisy Environment
Transition State Theory overestimates reaction rates in solution because
conventional dividing surfaces between reagents and products are crossed many
times by the same reactive trajectory. We describe a recipe for constructing a
time-dependent dividing surface free of such recrossings in the presence of
noise. The no-recrossing limit of Transition State Theory thus becomes
generally available for the description of reactions in a fluctuating
environment
The broad band X-ray spectrum of the black hole candidate GRS1758-258
We present the results of a BeppoSAX observation of the black hole candidate
GRS1758-258 carried out in 1997, while the source was in its low/hard state.
The X-ray spectrum, simultaneously observed over the broad energy range from
0.1 to 200 keV, can be well described by a Comptonized emission model with
electron temperature kT_e = 31.4 keV and optical depth of 4.0 (spherical
geometry), although a cut-off power-law and a reflection model cannot be
excluded. Additionally, a broad iron line at 6.4 keV with equivalent width EW =
67 eV has been marginally detected. The 0.1-200 keV luminosity is 1.4x10^37
erg/s for an assumed distance of 8 kpc. The soft and hard luminosities are such
that the source falls inside the so-called "burster box". No evidence for a
soft excess is present.Comment: accepted for publication in Astronomy and Astrophysic
Accountability, Strategy, and International Non-Governmental Organizations
Increased prominence and greater influence expose international non-governmental development and environmental organizations (INGOs) to increased demands for accountability from a wide variety of stakeholdersdonors, beneficiaries, staffs, and partners among others. This paper focuses on developing the concept of INGO accountability, first as an abstract concept and then as a strategic idea with very different implications for different INGO strategies. We examine those implications for INGOs that emphasize service delivery, capacity-building, and policy influence. We propose that INGOs committed to service delivery may owe more accountability to donors and service regulators; capacity-building INGOs may be particularly obligated to clients whose capacities are being enhanced; and policy influence INGOs may be especially accountable to political constituencies and to influence targets. INGOs that are expanding their activities to include new initiatives may need to reorganize their accountability systems to implement their strategies effectively. This publication is Hauser Center Working Paper No. 7. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers
Deep breathing couples CSF and venous flow dynamics
Venous system pathologies have increasingly been linked to clinically relevant disorders of CSF circulation whereas the exact coupling mechanisms still remain unknown. In this work, flow dynamics of both systems were studied using real-time phase-contrast flow MRI in 16 healthy subjects during normal and forced breathing. Flow evaluations in the aqueduct, at cervical level C3 and lumbar level L3 for both the CSF and venous fluid systems reveal temporal modulations by forced respiration. During normal breathing cardiac-related flow modulations prevailed, while forced breathing shifted the dominant frequency of both CSF and venous flow spectra towards the respiratory component and prompted a correlation between CSF and venous flow in the large vessels. The average of flow magnitude of CSF was increased during forced breathing at all spinal and intracranial positions. Venous flow in the large vessels of the upper body decreased and in the lower body increased during forced breathing. Deep respiration couples interdependent venous and brain fluid flow—most likely mediated by intrathoracic and intraabdominal pressure changes. Further insights into the driving forces of CSF and venous circulation and their correlation will facilitate our understanding how the venous system links to intracranial pressure regulation and of related forms of hydrocephalus
NuSTAR and Suzaku X-ray Spectroscopy of NGC 4151: Evidence for Reflection from the Inner Accretion Disk
We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear
Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the
Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption,
and reflection properties of the active galactic nucleus (AGN) by applying
inner accretion disk reflection and absorption-dominated models. With a
time-averaged spectral analysis, we find strong evidence for relativistic
reflection from the inner accretion disk. We find that relativistic emission
arises from a highly ionized inner accretion disk with a steep emissivity
profile, which suggests an intense, compact illuminating source. We find a
preliminary, near-maximal black hole spin a>0.9 accounting for statistical and
systematic modeling errors. We find a relatively moderate reflection fraction
with respect to predictions for the lamp post geometry, in which the
illuminating corona is modeled as a point source. Through a time-resolved
spectral analysis, we find that modest coronal and inner disk reflection flux
variation drives the spectral variability during the observations. We discuss
various physical scenarios for the inner disk reflection model, and we find
that a compact corona is consistent with the observed features.Comment: 20 pages, 12 figures, accepted for publication in Ap
Relationship tensions and mood: Adult children’s daily experience of aging parents’ stubbornness
This study examined middle‐aged individuals’ reports of parents’ behaviors commonly attributed to stubbornness. Middle‐aged adults (N = 192) completed a 7‐day diary reporting their mood and how often they felt their parents (N = 254) engaged in behaviors often described as “stubbornness” (insistent or risky). Thirty‐one percent of middle‐aged children reported insistent behaviors, and 17% reported risky behaviors by their parent(s). Daily reports of parent behaviors attributed to stubbornness were positively associated with parent–child relationship quality, parent functional limitations, and child neuroticism. Reports of perceived parent insistent behaviors were also associated with greater daily negative mood among adult children. Findings highlight the impact of adult children’s daily perceptions of parent behaviors commonly attributed to stubbornness on the individual and relationship.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142899/1/pere12229_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142899/2/pere12229.pd
Are personality disorders in bipolar patients more frequent in the US than Europe?
Objective: Bipolar patients in the United States (US) compared to those from the Netherlands and Germany (here abbrev. as “Europe”) have more Axis I comorbidities and more poor prognosis factors such as early onset and psychosocial adversity in childhood. We wished to examine whether these differences also extended to Axis II personality disorders (PDs). Methods: 793 outpatients with bipolar disorder diagnosed by SCID gave informed consent for participating in a prospective longitudinal follow up study with clinician ratings at each visit. They completed detailed patient questionnaires and a 99 item personality disorder inventory (PDQ-4). US versus European differences in PDs were examined in univariate analyses and then logistic regressions, controlling for severity of depression, age, gender, and other poor prognosis factors. Results: In the univariate analysis, 7 PDs were more prevalent in the US than in Europe, including antisocial, avoidant, borderline, depressive, histrionic, obsessive compulsive, and schizoid PDs. In the multivariate analysis, the last 4 of these PDs remained independently greater in the US than Europe. Conclusions: Although limited by use of self report and other potentially confounding factors, multiple PDs were more prevalent in the US than in Europe, but these preliminary findings need to be confirmed using other methodologies. Other poor prognosis factors are prevalent in the US, including early age of onset, more childhood adversity, anxiety and substance abuse comorbidity, and more episodes and rapid cycling. The interactions among these variables in relationship to the more adverse course of illness in the US than in Europe require further study
On two-dimensional Bessel functions
The general properties of two-dimensional generalized Bessel functions are
discussed. Various asymptotic approximations are derived and applied to analyze
the basic structure of the two-dimensional Bessel functions as well as their
nodal lines.Comment: 25 pages, 17 figure
Rigid Supersymmetric Theories in Curved Superspace
We present a uniform treatment of rigid supersymmetric field theories in a
curved spacetime , focusing on four-dimensional theories with four
supercharges. Our discussion is significantly simpler than earlier treatments,
because we use classical background values of the auxiliary fields in the
supergravity multiplet. We demonstrate our procedure using several examples.
For we reproduce the known results in the literature. A
supersymmetric Lagrangian for exists, but unless the
field theory is conformal, it is not reflection positive. We derive the
Lagrangian for and note that the
time direction can be rotated to Euclidean signature and be
compactified to only when the theory has a continuous R-symmetry. The
partition function on is independent of
the parameters of the flat space theory and depends holomorphically on some
complex background gauge fields. We also consider R-invariant
theories on and clarify a few points about them.Comment: 26 pages, uses harvmac; v2 with added reference
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