scholarly journals Ensemble slice sampling

2021 ◽  
Vol 31 (5) ◽  
Author(s):  
Minas Karamanis ◽  
Florian Beutler
Keyword(s):  
Monte Carlo Algorithm ◽  
Mcmc Methods ◽  
Length Scale ◽  
Strongly Correlated ◽  
Affine Invariant ◽  
Initial Length ◽  
High Dimensions ◽  
Slice Sampling ◽  
Order Of Magnitude ◽  
Highly Correlated

AbstractSlice sampling has emerged as a powerful Markov Chain Monte Carlo algorithm that adapts to the characteristics of the target distribution with minimal hand-tuning. However, Slice Sampling’s performance is highly sensitive to the user-specified initial length scale hyperparameter and the method generally struggles with poorly scaled or strongly correlated distributions. This paper introduces Ensemble Slice Sampling (ESS), a new class of algorithms that bypasses such difficulties by adaptively tuning the initial length scale and utilising an ensemble of parallel walkers in order to efficiently handle strong correlations between parameters. These affine-invariant algorithms are trivial to construct, require no hand-tuning, and can easily be implemented in parallel computing environments. Empirical tests show that Ensemble Slice Sampling can improve efficiency by more than an order of magnitude compared to conventional MCMC methods on a broad range of highly correlated target distributions. In cases of strongly multimodal target distributions, Ensemble Slice Sampling can sample efficiently even in high dimensions. We argue that the parallel, black-box and gradient-free nature of the method renders it ideal for use in scientific fields such as physics, astrophysics and cosmology which are dominated by a wide variety of computationally expensive and non-differentiable models.

Culturally Sensitive Assessment of Anxious-Depressive Distress in Vietnam: Avoiding Category Truncation

2018 ◽  
Vol 55 (3) ◽  
pp. 384-404 ◽  
Author(s):  
Devon E. Hinton ◽  
Amie Alley Pollack ◽  
Bahr Weiss ◽  
Lam T. Trung
Keyword(s):  
Psychiatric Symptoms ◽  
Anxiety And Depression ◽  
Strongly Correlated ◽  
General Survey ◽  
General Anxiety Disorder ◽  
General Anxiety ◽  
Study Results ◽  
Standing Up ◽  
Patient Health ◽  
Highly Correlated

The present study investigated what complaints are prominent in psychologically distressed Vietnamese in Vietnam beyond standard symptoms assessed by Western diagnostic instruments for anxiety and depression. To form the initial Vietnamese Symptom and Cultural Syndrome Addendum (VN SSA), we reviewed the literature, consulted experts, and conducted focus groups. The preliminary VN SSA was then used in a general survey (N = 1004) of five provinces in Vietnam. We found that the VN SSA items were highly and significantly correlated with a measure of anxious-depressive psychopathology (a composite measure of the General Anxiety Disorder-7; Posttraumatic Diagnostic Scale; and Patient Health Questionnaire-9). The VN SSA item most highly correlated to anxious-depressive psychopathology was “thinking a lot” ( r = .54), reported by 15.8% of the sample. Many other symptoms in the addendum also were prominent, such as orthostatic dizziness (i.e., dizziness upon standing up; r = .41), reported by 22.9% of the sample. By way of comparison, somatic complaints more typically assessed to profile Western anxious-depressive distress, such as palpitations, were less prominent, as evidenced by being less strongly correlated to Western psychiatric symptoms and being less frequent (e.g., palpitations: r = .31, 7.1% of the sample). Study results suggest that to avoid category truncation when profiling anxious-depressive distress among Vietnamese that items other than those in standard psychopathology measures should also be assessed.

scholarly journals Inferring object properties from human interaction and transferring them to new motions

2021 ◽  
Author(s):  
Qian Zheng ◽  
Weikai Wu ◽  
Hanting Pan ◽  
Niloy Mitra ◽  
Daniel Cohen-Or ◽  
...  
Keyword(s):  
Human Interaction ◽  
Strongly Correlated ◽  
Recognition Method ◽  
Fine Grained ◽  
Object Property ◽  
Correlated Motions ◽  
Object Properties ◽  
New Synthesis ◽  
Related Object ◽  
Highly Correlated

AbstractHumans regularly interact with their surrounding objects. Such interactions often result in strongly correlated motions between humans and the interacting objects. We thus ask: “Is it possible to infer object properties from skeletal motion alone, even without seeing the interacting object itself?” In this paper, we present a fine-grained action recognition method that learns to infer such latent object properties from human interaction motion alone. This inference allows us to disentangle the motion from the object property and transfer object properties to a given motion. We collected a large number of videos and 3D skeletal motions of performing actors using an inertial motion capture device. We analyzed similar actions and learned subtle differences between them to reveal latent properties of the interacting objects. In particular, we learned to identify the interacting object, by estimating its weight, or its spillability. Our results clearly demonstrate that motions and interacting objects are highly correlated and that related object latent properties can be inferred from 3D skeleton sequences alone, leading to new synthesis possibilities for motions involving human interaction. Our dataset is available at http://vcc.szu.edu.cn/research/2020/IT.html.

Meat qualities in the sheep with special reference to Scottish breeds and crosses. I

1939 ◽  
Vol 29 (4) ◽  
pp. 544-626 ◽  
Author(s):  
H. Pálsson
Keyword(s):  
Scientific Basis ◽  
Accurate Estimate ◽  
Quantitative Composition ◽  
Carcass Quality ◽  
Strongly Correlated ◽  
Precise Measure ◽  
Total Fat ◽  
Highly Correlated ◽  
High Degree ◽  
The Relationship

1. By establishing the relationship between linear carcass measurements and the quantitative composition of the carcass in terms of bone, muscle and fat, we have provided a scientific basis for the use of many measurements hitherto only presumed to provide an index to carcass quality.2. External carcass measurements are correlated with weight of the skeleton. The most useful for this purpose are length of tibia + tarsus and length of the fore-cannon.3. As indices of muscle, external measures are only of indirect value. Thus, both F – T and G/F × 100 are strongly correlated with weight of muscle as a percentage of skeletal weight.4. Similarly, F provides an index of fat, being negatively correlated with fat as a percentage of bone.5. For muscle and fat internal measures permit a more precise estimate to be made. A + B is the best index of the former while C + J + Y provide the most accurate estimate of the weight of fat.6. Still better indices for muscle and fat are provided by suitable combinations of external and internal measurements. Thus L/10 + A + B is very highly correlated with the weight of muscle, and L/10 × (C + J + Y) is the best index of fat in the hoggets. For bone, a most efficient single index is shown to be the weight of the fore-cannon bone.7. The weight of the skeleton can be estimated with a high degree of accuracy from the weight of the bones in either one leg or loin. Both these joints combined, however, provide a still better estimate.8. The muscle in one leg or loin + leg provides an excellent index of the weight of muscle in the whole carcass.9. The fat in one leg, loin, or both these joints combined provides a good index of the weight of the total fat in the carcass. Both joints combined give the most precise measure.10. The value of certain measurements which are not necessarily associated with the quantity of the major tissues of the carcass, but which nevertheless have important qualitative significance, is emphasized.

scholarly journals Biases in Thorpe-Scale Estimates of Turbulence Dissipation. Part I: Assessments from Large-Scale Overturns in Oceanographic Data

2015 ◽  
Vol 45 (10) ◽  
pp. 2497-2521 ◽  
Author(s):  
Benjamin D. Mater ◽  
Subhas K. Venayagamoorthy ◽  
Louis St. Laurent ◽  
James N. Moum
Keyword(s):  
Large Scale ◽  
Companion Paper ◽  
Open Ocean ◽  
Luzon Strait ◽  
Length Scale ◽  
Ensemble Averaging ◽  
Tidal Period ◽  
Thorpe Scale ◽  
Order Of Magnitude ◽  
A Site

AbstractOceanic density overturns are commonly used to parameterize the dissipation rate of turbulent kinetic energy. This method assumes a linear scaling between the Thorpe length scale LT and the Ozmidov length scale LO. Historic evidence supporting LT ~ LO has been shown for relatively weak shear-driven turbulence of the thermocline; however, little support for the method exists in regions of turbulence driven by the convective collapse of topographically influenced overturns that are large by open-ocean standards. This study presents a direct comparison of LT and LO, using vertical profiles of temperature and microstructure shear collected in the Luzon Strait—a site characterized by topographically influenced overturns up to O(100) m in scale. The comparison is also done for open-ocean sites in the Brazil basin and North Atlantic where overturns are generally smaller and due to different processes. A key result is that LT/LO increases with overturn size in a fashion similar to that observed in numerical studies of Kelvin–Helmholtz (K–H) instabilities for all sites but is most clear in data from the Luzon Strait. Resultant bias in parameterized dissipation is mitigated by ensemble averaging; however, a positive bias appears when instantaneous observations are depth and time integrated. For a series of profiles taken during a spring tidal period in the Luzon Strait, the integrated value is nearly an order of magnitude larger than that based on the microstructure observations. Physical arguments supporting LT ~ LO are revisited, and conceptual regimes explaining the relationship between LT/LO and a nondimensional overturn size are proposed. In a companion paper, Scotti obtains similar conclusions from energetics arguments and simulations.

scholarly journals A novel method of ESR oscillating magnetization value determination in strongly correlated metals

2018 ◽  
Vol 185 ◽  
pp. 02003 ◽  
Author(s):  
Marat Gilmanov ◽  
Alexey Semeno ◽  
Alexander Samarin ◽  
Sergey Demishev
Keyword(s):  
Resonance Field ◽  
Simple Expression ◽  
60 Ghz ◽  
Strongly Correlated ◽  
Static Magnetization ◽  
Spin Resonance ◽  
Order Of Magnitude ◽  
Novel Method ◽  
Value Determination ◽  
The One

We propose a powerful method of direct measurement of oscillating magnetization by the electron spin resonance, based on dependence of resonant conditions on geometry of the experiment. Theoretical consideration of the matter leads to a simple expression for oscillating magnetization. Approbation of this method is implemented by means of cavity ESR spectrometer (60 GHz) on two diverse metallic systems, where static magnetization at the resonance field varies by an order of magnitude. Quantitative values of oscillating magnetization (905 G for EuB6 at T = 4.2 K and 94 G for CeB6 at T = 1.8 K) are in appropriate agreement with the one obtained by the other methods.

The mobility and transformation of soil nitrogen and the relationships between soil and plant nitrogen and yield at different times following application of various nitrogen fertilizers to sweet corn

1992 ◽  
Vol 43 (7) ◽  
pp. 1643 ◽  
Author(s):  
AA Salardini ◽  
LA Sparrow ◽  
RJ Holloway
Keyword(s):  
Soil Nitrogen ◽  
Sweet Corn ◽  
Nitrogen Fertilizers ◽  
Yield Response ◽  
Strongly Correlated ◽  
Mineral N ◽  
N Application ◽  
Plant Nitrogen ◽  
Highly Correlated ◽  
Sampling Times

The concentration of NH4-N, NO3-N and their sum (mineral N) were monitored 12 times in 1 or 2 weekly intervals in the soil under a sweet corn crop. The samples were taken on the fertilizer band and to depths of 200, 400 and 600 mm. The NO3-N concentration of the sap expressed from the midrib of the leaf opposite and immediately above the primary cob (sap NO3-N) and that of midrib dry matter (midrib NO3-N) were determined weekly. Under the low rainfall and optimized irrigation of this trial the concentration of mineral N in soil to the depth of 400 mm or more was a good predictor of yield response to application of N at 10 of the 12 sampling times. The concentration of either NH4-N or NO3-N in the soil to any depth and the concentration of mineral N in the surface 200 mm correlated with the yield at only a few times of sampling. The concentration of mineral N in the top 200 mm of soil 1 or 2 weeks after top-dressing of N was highly correlated to yield. The concentration of sap NOS-N and midrib NO3-N decreased continuously until harvest. Both these concentrations were significantly correlated with the rates of basal and top-dressed N in most sampling times. These were also strongly correlated to yield 1 or 2 weeks after N top-dressing. Ammonium sulfate, ammonium nitrate and urea gave similar responses in sap NO3-N and midrib NO3-N and in soil nitrogen after 5 weeks when nitrification of fertilizer NH4-N was complete. These observations indicated that soil mineral N, sap NO3-N and midrib NO3-N all offer potential as techniques to predict the yield response of sweet corn to N application. The sap NO3-N test was simpler, quicker, cheaper and more consistent than other tests.

scholarly journals Antimicrobial defences increase with sociality in bees

2007 ◽  
Vol 3 (4) ◽  
pp. 422-424 ◽  
Author(s):  
Adam Stow ◽  
David Briscoe ◽  
Michael Gillings ◽  
Marita Holley ◽  
Shannon Smith ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Genetic Relatedness ◽  
Microbial Pathogens ◽  
Strongly Correlated ◽  
Social Species ◽  
Evolution Of Sociality ◽  
Selective Agents ◽  
Order Of Magnitude ◽  
Risk Of Disease ◽  
Solitary Species

Evidence for the antiquity and importance of microbial pathogens as selective agents is found in the proliferation of antimicrobial defences throughout the animal kingdom. Social insects, typified by crowding and often by low genetic variation, have high probabilities of disease transmission and eusocial Hymenoptera may be particularly vulnerable because of haplodiploidy. Mechanisms they employ to reduce the risk of disease include antimicrobial secretions which are particularly important primary barriers to infection. However, until now, whether or not there is selection for stronger antimicrobial secretions when the risk of disease increases because of sociality has not been tested. Here, we present evidence that the production of progressively stronger antimicrobial compounds was critical to the evolution of sociality in bees. We found that increases in group size and genetic relatedness were strongly correlated with increasing antimicrobial strength. The antimicrobials of even the most primitive semi-social species were an order of magnitude stronger that those of solitary species, suggesting a point of no return, beyond which disease control was essential. Our results suggest that selection by microbial pathogens was critical to the evolution of sociality and required the production of strong, front-line antimicrobial defences.

Uncertainty quantification in geological modelling by Hessian-informed MCMC

2020 ◽  
Author(s):  
Zhouji Liang ◽  
Florian Wellmann
Keyword(s):  
Uncertainty Quantification ◽  
Stochastic Modelling ◽  
High Dimensional ◽  
Mcmc Methods ◽  
Inference Problem ◽  
Model Interpretation ◽  
Geological Modelling ◽  
High Dimensional Problem ◽  
Recent Developments ◽  
Highly Correlated

<p>Uncertainty quantification is an important aspect of geological modelling and model interpretation. Recent developments in geological modelling allow us to view the inversion as a problem in Bayesian inference, incorporating the uncertainties in the observations, the forward models and the prior knowledge from geologists. The sampling method Markov chain Monte Carlo (MCMC) is then often applied to solve this inference problem. However, this stochastic modelling approach is limited as the number of parameters increases to higher dimensions. To ensure an efficient sampling in a high dimensional problem, we take advantage of recent advances using Hessian-based MCMC methods in this work. The Hessian of the negative log posterior with respect to the input parameters is evaluated at the Maximum a Posteriori (MAP) point. A Laplace approximation of the posterior at the MAP is then given by the inverse of the local Hessian. This sampling approach provides a potentially less computationally expensive and more efficient way for high dimensional geological inverse modelling, especially in cases where parameters are highly correlated, a situation that commonly arises in geological modelling.</p>

Changes of AI Receptive Fields With Sound Density

2002 ◽  
Vol 88 (6) ◽  
pp. 3409-3420 ◽  
Author(s):  
David T. Blake ◽  
Michael M. Merzenich
Keyword(s):  
Receptive Fields ◽  
Primary Auditory Cortex ◽  
Complex Sound ◽  
Spectral Selectivity ◽  
Inhibitory Population ◽  
Optimal Linear ◽  
Order Of Magnitude ◽  
Highly Correlated ◽  
Sound Density ◽  
High Sound

Primates engage in auditory behaviors under a broad range of signal-to-noise conditions. In this study, optimal linear receptive fields were measured in alert primate primary auditory cortex (A1) in response to stimuli that vary in spectrotemporal density. As density increased, A1 excitatory receptive fields systematically changed. Receptive field sensitivity, expressed as the expected change in firing rate after a tone pip onset, decreased by an order of magnitude. Spectral selectivity more than doubled. Inhibitory subfields, which were rarely recorded at low sound densities, emerged at higher sound densities. The ratio of excitatory to inhibitory population strength changed from 14.4:1 to 1.4:1. At low sound densities, the sound associated with the evocation of an action potential from an A1 neuron was broad in spectrum and time. At high sound densities, a spike-evoking sound was more likely to be a spectral or temporal edge and was narrower in time and frequency range. Receptive fields were used to predict responses to a novel high-noise-density stimulus. The predictions were highly correlated with the actual responses to the 2-s complex sound excerpt. The structure of prediction failures revealed that neurons with prominent inhibitory fields had relatively poor linear predictions. Further, the finding that stochastic variance is limiting in prediction even after averaging 150 repetitions means that high-fidelity representations of simple sounds in A1 must be distributed over at least hundreds of neurons. Auditory context alters A1 responses across multiple parameter spaces; this presents a challenge for reconstructing neural codes.

scholarly journals The relative validity and repeatability of an FFQ for estimating intake of zinc and its absorption modifiers in young and older Saudi adults

2014 ◽  
Vol 18 (6) ◽  
pp. 968-976 ◽  
Author(s):  
Hadeil M Alsufiani ◽  
Fatmah Yamani ◽  
Taha A Kumosani ◽  
Dianne Ford ◽  
John C Mathers
Keyword(s):  
Phytic Acid ◽  
Strongly Correlated ◽  
Food Record ◽  
Age And Gender ◽  
Relative Validity ◽  
Males And Females ◽  
The Difference ◽  
Highly Correlated ◽  
And Gender ◽  
Gender Groups

AbstractObjectiveTo assess the relative validity and repeatability of a sixty-four-item FFQ for estimating dietary intake of Zn and its absorption modifiers in Saudi adults. In addition, we used the FFQ to investigate the effect of age and gender on these intakes.DesignTo assess validity, all participants completed the FFQ (FFQ1) and a 3 d food record. After 1 month, the FFQ was administered for a second time (FFQ2) to assess repeatability.SettingJeddah, Saudi Arabia.SubjectsOne hundred males and females aged 20–30 years and 60–70 years participated.ResultsMean intakes of Zn and protein from FFQ1 were significantly higher than those from the food record while there were no detectable differences between tools for measurement of phytic acid intake. Estimated intakes of Zn, protein and phytate by both approaches were strongly correlated (P<0·001). Bland–Altman analysis showed for protein that the difference in intake as measured by the two methods was similar across the range of intakes while for Zn and phytic acid, the difference increased with increasing mean intake. Zn and protein intakes from FFQ1 and FFQ2 were highly correlated (r>0·68,P<0·001) but were significantly lower at the second measurement (FFQ2). Older adults consumed less Zn and protein compared with young adults. Intakes of all dietary components were lower in females than in males.ConclusionsThe FFQ developed and tested in the current study demonstrated reasonable relative validity and high repeatability and was capable of detecting differences in intakes between age and gender groups.

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