Raloxifene Improves Cognition in Schizophrenia: Spurious Result or Valid Effect?

AbstractWe present wide-field, spatially and highly resolved spectroscopic observations of Balmer filaments in the northeastern rim of Tycho’s supernova remnant in order to investigate the signal of cosmic-ray (CR) acceleration. The spectra of Balmer-dominated shocks (BDSs) have characteristic narrow (FWHM ~ 10 km s−1) and broad (FWHM ~ 1000 km s−1) Hα components. CRs affect the Hα-line parameters: heating the cold neutrals in the interstellar medium results in broadening of the narrow Hα-line width beyond 20 km s−1, but also in reduction of the broad Hα-line width due to energy being removed from the protons in the post-shock region. For the first time we show that the width of the narrow Hα line, much larger than 20 km s−1, is not a resolution or geometric effect nor a spurious result of a neglected intermediate (FWHM ~ 100 km s−1) component resulting from hydrogen atoms undergoing charge exchange with warm protons in the broad-neutral precursor. Moreover, we show that a narrow line width ≫ 20 km s−1extends across the entire NE rim, implying CR acceleration is ubiquitous, and making it possible to relate its strength to locally varying shock conditions. Finally, we find several locations along the rim, where spectra are significantly better explained (based on Bayesian evidence) by inclusion of the intermediate component, with a width of 180 km s−1on average.

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Model Atmospheres and Radiative Transfer in Chemically Peculiar Stars: Interpretational Significance of Non-LTE

International Astronomical Union Colloquium ◽

10.1017/s0252921100091235 ◽

1986 ◽

Vol 90 ◽

pp. 57-75

Author(s):

I. Hubený

Keyword(s):

Local Thermodynamic Equilibrium ◽

Rapid Development ◽

Abundance Distribution ◽

Hot Stars ◽

Chemically Peculiar ◽

Peculiar Stars ◽

Traditional Assumption ◽

Abundance Anomalies ◽

Chemically Peculiar Stars ◽

Spurious Result

One of the main problems in studying chemically peculiar (CP) stars is the question of the extent to which the conceptual framework of the contemporary spectroscopic diagnostics is reliable. As the first step, it should be clarified whether the traditional assumption of local thermodynamic equilibrium (LTE) provides an adequate approximation to reality, or whether a more general non-LTE approach should be employed.The period of rapid development of computational methods and extensive calculations of NLTE model atmospheres is now past its culmination point. The importance of a relevant NLTE description is viewed as unquestionable for hot stars (B and earlier). Consequently, the hot stars attract the attention of most “NLTE theoreticians,” while considerably less attention is being devoted to later types (late B and A). Moreover, the abundance anomalies found in the CP stars are no longer expected to be a spurious result of an inadequate (LTE) analysis (Cowley 1981). It is not commonly accepted that other phenomena such as diffusion, magnetic field, inhomogeneous abundance distribution, etc., are quite essential ingredients of the general atmospheric pattern of CP stars. Therefore, a large part of the astronomers investigating the CP stars now consider the NLTE effects to be rather minor perturbations of the LTE predictions.

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Use of the F test for determining the degree of enzyme-kinetic and ligand-binding data. A Monte Carlo simulation study

Biochemical Journal ◽

10.1042/bj2110023 ◽

1983 ◽

Vol 211 (1) ◽

pp. 23-34 ◽

Cited By ~ 35

Author(s):

F J Burguillo ◽

A J Wright ◽

W G Bardsley

Keyword(s):

Rate Equation ◽

Confidence Level ◽

Substrate Concentration ◽

Rational Functions ◽

F Test ◽

Monte Carlo Simulation Study ◽

Confidence Levels ◽

Binding Data ◽

Binding Polynomial ◽

Spurious Result

1. Initial-rate data were simulated for 13 representative enzyme mechanisms with the use of several distributions of rate constants in order to locate conditions leading to v([S]) curves in physiological ranges of substrate concentration. 2. In all, 420 sets of such v([S]) curves were generated with the use of several choices of substrate concentration range (two, three or four orders of magnitude), number of experimental points (10, 15 or 20), error on v (5-10%) and standard deviation on v (5-9%) in order to simulate experimental results in a number of possible ways. 3. Curve-fitting was carried out to rational functions of degree 1:1, 2:2, …, 5:5 until there was no statistically significant decrease in the sum of weighted squared residuals as judged by the F test at 95% and 99% confidence levels. 4. It was checked whether the non-linear regression program had located a good minimum in the sum of squares by also fitting the data with the correct values of parameters as starting estimates. 5. A similar procedure was adopted with 110 sets of binding data simulated for 11 models, and the F test was used to see if fractional-saturation data generated by a binding polynomial of order n could be adequately fitted by one of order m, m less than n. 6. From the 530 simulations the F test was successful in fixing the correct degree with a probability of 0.62 at the 95% confidence level, but this fell with increase in degree as follows: 1:1 (0.98), 2:2 (0.71), 3:3 (0.43) and 4:4 (0.34), the first numbers being the degree of the rate equation and those in parentheses referring to the 95% confidence level. 7. It made little difference whether the 95% or the 99% confidence level was consulted, as there were very few borderline cases. 8. The chance of detecting deviations from Michaelis-Menten kinetics, i.e. terms of at least second-order in a rate equation of degree n:n, n greater than 1, was estimated to be about 0.8. 9. The probability of the F test leading to a spurious result due to error in the data was found to be about 0.04. 10. The probability with which 4:4 mechanisms can lead to v([S]) plots with no, one, two or three turning points was computed, and it was established that there is a small but finite chance that the increase in degree that occurs in some mechanisms when ES in equilibrium EP interconversions are explicitly allowed for can be detected by the F test.

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Winners or Losers? Democracies in International Crisis, 1918–94

American Political Science Review ◽

10.1017/s0003055401003148 ◽

2001 ◽

Vol 95 (3) ◽

pp. 633-647 ◽

Cited By ~ 112

Author(s):

Christopher F. Gelpi ◽

Michael Griesdorf

Keyword(s):

Strong Evidence ◽

Democratic Peace ◽

International Conflicts ◽

International Crises ◽

International Crisis ◽

Audience Costs ◽

Common Interests ◽

Political Structures ◽

The Many ◽

Spurious Result

We attempt to explain when and why democratic states will prevail in international crises. We review several of the prominent theories about democratic political structures and derive hypotheses from each framework about crisis outcomes. These hypotheses are tested against the population of 422 international crises between 1918 and 1994. Our findings provide further evidence that the democratic peace is not a spurious result of common interests. Moreover, we also begin the difficult task of differentiating among the many theories of the democratic peace. In particular, we find strong evidence that democratic political structures are important because of their ability to generate domestic audience costs. Our findings also support the argument that democratic political structures encourage leaders to select international conflicts that they will win.

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I TRIED A BUNCH OF THINGS: THE DANGERS OF UNEXPECTED OVERFITTING IN CLASSIFICATION

10.1101/078816 ◽

2016 ◽

Cited By ~ 13

Author(s):

Michael Powell ◽

Mahan Hosseini ◽

John Collins ◽

Chloe Callahan-Flintoft ◽

William Jones ◽

...

Keyword(s):

Machine Learning ◽

Cross Validation ◽

Machine Learning Techniques ◽

Random Data ◽

Effective Protection ◽

Data Set ◽

Learning Techniques ◽

Original Analysis ◽

Spurious Result ◽

Spurious Results

ABSTRACTMachine learning is a powerful set of techniques that has enhanced the abilities of neuroscientists to interpret information collected through EEG, fMRI, and MEG data. With these powerful techniques comes the danger of overfitting of hyper-parameters which can render results invalid, and cause a failure to generalize beyond the data set. We refer to this problem as ‘over-hyping’ and show that it is pernicious despite commonly used precautions. In particular, over-hyping occurs when an analysis is run repeatedly with slightly different analysis parameters and one set of results is selected based on the analysis. When this is done, the resulting method is unlikely to generalize to a new dataset, rendering it a partially, or perhaps even completely spurious result that will not be valid outside of the data used in the original analysis. While it is commonly assumed that cross-validation is an effective protection against such spurious results generated through overfitting or overhyping, this is not actually true. In this article, we show that both one-shot and iterative optimization of an analysis are prone to over-hyping, despite the use of cross-validation. We demonstrate that non-generalizable results can be obtained even on non-informative (i.e. random) data by modifying hyper-parameters in seemingly innocuous ways. We recommend a number of techniques for limiting over-hyping, such as lock-boxes, blind analyses, pre-registrations, and nested cross-validation. These techniques, are common in other fields that use machine learning, including computer science and physics. Adopting similar safeguards is critical for ensuring the robustness of machine-learning techniques in the neurosciences.

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Sensitivity analysis is a useful tool for detecting influential observations

10.31234/osf.io/z3wvm ◽

2019 ◽

Author(s):

Samuel A Mehr

Keyword(s):

Sensitivity Analysis ◽

Positive Psychology ◽

Data Collection ◽

False Positive ◽

Original Data ◽

Influential Observations ◽

Data Collection And Analysis ◽

Spurious Result

I ran a sensitivity analysis on the original data from "False-positive psychology: Undisclosed flexibility in data collection and analysis allows presenting anything as significant." (Simmons et al., 2011, Psych Science) and found that the intentionally spurious result reported therein was attributable to a single outlier. This is presented as an example of why sensitivity analysis is a useful piece of the analytic toolkit in psychology.

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Spread of effect is the spurious result of non-random response tendencies.

Journal of Experimental Psychology ◽

10.1037/h0057257 ◽

1949 ◽

Vol 39 (3) ◽

pp. 355-368 ◽

Cited By ~ 5

Author(s):

Moncrieff H. Smith

Keyword(s):

Random Response ◽

Spurious Result

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Are Some Stellar Coronae Optically Thick?

International Astronomical Union Colloquium ◽

10.1017/s0252921100035843 ◽

1996 ◽

Vol 152 ◽

pp. 121-128

Author(s):

C.J. Schrijver ◽

G.H.J. van den Oord ◽

R. Mewe ◽

J.S. Kaastra

Keyword(s):

Extreme Ultraviolet ◽

Formal Solution ◽

Emission Measure ◽

Resonant Scattering ◽

Heavy Elements ◽

Volume Filling ◽

Dominant Component ◽

Weak Component ◽

Cool Stars ◽

Spurious Result

We discuss the coronal spectra of a sample of cool stars observed with the spectrometers of the Extreme Ultraviolet Explorer (EUVE). The emission measure distributions show (a) a relatively weak component between 0.1 MK and 1 MK, (b) a dominant component somewhere between 2 MK and 10 MK, and (c) in all cases but one a component in the formal solution at temperatures exceeding ≈ 20 MK. Where this hot tail is not associated with a real hot component, it is a spurious result reflecting a lowered line-to-continuum ratio, which, for instance, may be the result of a low abundance of heavy elements or of resonant scattering in some of the strongest coronal lines. We suggest that in Procyon’s corona photons in the strongest lines formed around a few million Kelvin undergo resonant scattering in a circumstellar medium, possibly a stellar wind. The flare spectrum of AU Mic suggests that resonant scattering may also occur in dense, hot flare plasmas. The electron densities of the 5–15 MK component are some three orders of magnitude higher than typical of the solar-like component around 2 MK; the volume filling factors of the hot components are therefore expected to be relatively small.

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The Influence of Corporate Governance on Environmental Disclosure of Listed Non-Financial Firms in Nigeria

Indonesian Journal of Sustainability Accounting and Management ◽

10.28992/ijsam.v2i1.47 ◽

2018 ◽

Vol 2 (1) ◽

pp. 25 ◽

Cited By ~ 7

Author(s):

Ndubuisi Odoemelam ◽

Regina Okafor

Keyword(s):

Corporate Governance ◽

Audit Committee ◽

Stock Exchange ◽

Environmental Law ◽

Environmental Reporting ◽

Environmental Disclosure ◽

Cross Sectional ◽

Financial Firms ◽

Industry Membership ◽

Spurious Result

The study investigates the influence of corporate governance on environmental disclosure of non-financial firms listed in Nigeria Stock Exchange (NSE), anchoring on “trinity theory” (agency, stakeholder and legitimacy theories). 86 firm-year observations across 86 companies listed in Nigeria Stock Exchange (NSE) using content analysis, cross-sectional data, OLS regression techniques were used to analyze the influence of board characteristics on the extent of overall environmental disclosure (OED). The results show that board independence, board meeting and the environmental committee were statistically significant while audit committee independence and board size were insignificant. Among the three company attributes used to mitigate spurious result only Firm size significantly influence the quantity of overall environmental disclosure of the sample companies. Auditor type “big 4” (Ernest Young, Deloitte, KPMG and PWC) and industry membership show insignificant relation to environmental disclosure. The findings indicate that the level of environmental disclosure of nonfinancial companies in Nigeria is quite insufficient at an average of 10.5 %. It is not surprising that environmentally sensitive industry and auditor type had no significant influence on the extent of environmental disclosure. This buttress the point that the environment the companies operate is institutionally and legally weak. Hence it calls for improvement on environmental law and implementation as well as harmonized environmental reporting infrastructure and standard to aid comparison.

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