3,064 research outputs found
Networks of Recurrent Events, a Theory of Records, and an Application to Finding Causal Signatures in Seismicity
We propose a method to search for signs of causal structure in spatiotemporal
data making minimal a priori assumptions about the underlying dynamics. To this
end, we generalize the elementary concept of recurrence for a point process in
time to recurrent events in space and time. An event is defined to be a
recurrence of any previous event if it is closer to it in space than all the
intervening events. As such, each sequence of recurrences for a given event is
a record breaking process. This definition provides a strictly data driven
technique to search for structure. Defining events to be nodes, and linking
each event to its recurrences, generates a network of recurrent events.
Significant deviations in properties of that network compared to networks
arising from random processes allows one to infer attributes of the causal
dynamics that generate observable correlations in the patterns. We derive
analytically a number of properties for the network of recurrent events
composed by a random process. We extend the theory of records to treat not only
the variable where records happen, but also time as continuous. In this way, we
construct a fully symmetric theory of records leading to a number of new
results. Those analytic results are compared to the properties of a network
synthesized from earthquakes in Southern California. Significant disparities
from the ensemble of acausal networks that can be plausibly attributed to the
causal structure of seismicity are: (1) Invariance of network statistics with
the time span of the events considered, (2) Appearance of a fundamental length
scale for recurrences, independent of the time span of the catalog, which is
consistent with observations of the ``rupture length'', (3) Hierarchy in the
distances and times of subsequent recurrences.Comment: 19 pages, 13 figure
In-situ characterization of the thermal state of resonant optical interferometers via tracking of their higher-order mode resonances
Thermal lensing in resonant optical interferometers such as those used for
gravitational wave detection is a concern due to the negative impact on control
signals and instrument sensitivity. In this paper we describe a method for
monitoring the thermal state of such interferometers by probing the
higher-order spatial mode resonances of the cavities within them. We
demonstrate the use of this technique to measure changes in the Advanced LIGO
input mode cleaner cavity geometry as a function of input power, and
subsequently infer the optical absorption at the mirror surfaces at the level
of 1 ppm per mirror. We also demonstrate the generation of a useful error
signal for thermal state of the Advanced LIGO power recycling cavity by
continuously tracking the first order spatial mode resonance frequency. Such an
error signal could be used as an input to thermal compensation systems to
maintain the interferometer cavity geometries in the presence of transients in
circulating light power levels, thereby maintaining optimal sensitivity and
maximizing the duty-cycle of the detectors
Dosing pole recommendations for lymphatic filariasis elimination: A height-weight quantile regression modeling approach
BACKGROUND: The World Health Organization (WHO) currently recommends height or age-based dosing as alternatives to weight-based dosing for mass drug administration lymphatic filariasis (LF) elimination programs. The goals of our study were to compare these alternative dosing strategies to weight-based dosing and to develop and evaluate new height-based dosing pole scenarios.
METHODOLOGY/PRINCIPAL FINDINGS: Age, height and weight data were collected from \u3e26,000 individuals in five countries during a cluster randomized LF clinical trial. Weight-based dosing for diethylcarbamazine (DEC; 6 mg/kg) and ivermectin (IVM; 200 ug/kg) with tablet numbers derived from a table of weight intervals was treated as the gold standard for this study. Following WHO recommended age-based dosing of DEC and height-based dosing of IVM would have resulted in 32% and 27% of individuals receiving treatment doses below those recommended by weight-based dosing for DEC and IVM, respectively. Underdosing would have been especially common in adult males, who tend to have the highest LF prevalence in many endemic areas. We used a 3-step modeling approach to develop and evaluate new dosing pole cutoffs. First, we analyzed the clinical trial data using quantile regression to predict weight from height. We then used weight predictions to develop new dosing pole cutoff values. Finally, we compared different dosing pole cutoffs and age and height-based WHO dosing recommendations to weight-based dosing. We considered hundreds of scenarios including country- and sex-specific dosing poles. A simple dosing pole with a 6-tablet maximum for both DEC and IVM reduced the underdosing rate by 30% and 21%, respectively, and was nearly as effective as more complex pole combinations for reducing underdosing.
CONCLUSIONS/SIGNIFICANCE: Using a novel modeling approach, we developed a simple dosing pole that would markedly reduce underdosing for DEC and IVM in MDA programs compared to current WHO recommended height or age-based dosing
Clergy work-related satisfactions in parochial ministry: the influence of personality and churchmanship
The aim of this study was to test several hypotheses that clergy work-related satisfaction could be better explained by a multidimensional rather than a unidimensional model. A sample of 1071 male stipendiary parochial clergy in the Church of England completed the Clergy Role Inventory, together with the short-form Revised Eysenck Personality Questionnaire. Factor analysis of the Clergy Role Inventory identified five separate clergy roles: Religious Instruction, Administration, Statutory Duties (conducting marriages and funerals), Pastoral Care, and Role Extension (including extra-parochial activities). Respondents also provided an indication of their predispositions on the catholic-evangelical and liberal-conservative dimensions. The significant associations of the satisfactions derived from each of the roles with the demographic, personality, and churchmanship variables were numerous, varied, and, with few exceptions, small in magnitude. Separate hierarchical regressions for each of the five roles indicated that the proportion of total variance explained by churchmanship was, in general, at least as great as that explained by personality, and was greater for three roles: Religious Instruction, Statutory Duties, and Role Extension. It was concluded that clergy satisfactions derived from different roles are not uniform and that churchmanship is at least as important as personality in accounting for clergy work satisfaction
Finding Needles in Haystacks: The Use of Quantitative Proteomics for the Early Detection of Colorectal Cancer
Colorectal cancer (CRC) is a common and treatable disease if diagnosed early. Current population screening programs are suboptimal, and consequently, there is a need for the development of new methodologies for early diagnosis of CRC. In the past 10 years, unprecedented technological advancements in the field of mass spectrometry (MS)-based proteomics have progressively increased the sophistication and utility of these investigations, leading to the draft mapping of the human proteome. These exciting studies have shaped our mechanistic understanding of the human genome and begun to provide us with a suite of novel biomarkers to predict the onset, progression and severity of many debilitating diseases. Thus, sophisticated MS workflows coupled with revolutionary protein quantification techniques hold promise for the field of MS-based plasma proteomics, particularly valuable in the context of early stage identification of curable CRC. However, within the last 40 years, no new plasma protein biomarkers of CRC have been translated into clinical practice. Here. we discuss the application of proteomic technologies within the field of CRC, highlighting contemporary MS-based plasma proteomic strategies that could be exploited to deliver on the promise of a panel of sensitive and specific plasma-based biomarkers with which to non-invasively detect early stage CRC
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