656 research outputs found
Visual BFI: an Exploratory Study for Image-based Personality Test
This paper positions and explores the topic of image-based personality test.
Instead of responding to text-based questions, the subjects will be provided a
set of "choose-your-favorite-image" visual questions. With the image options of
each question belonging to the same concept, the subjects' personality traits
are estimated by observing their preferences of images under several unique
concepts. The solution to design such an image-based personality test consists
of concept-question identification and image-option selection. We have
presented a preliminary framework to regularize these two steps in this
exploratory study. A demo version of the designed image-based personality test
is available at http://www.visualbfi.org/. Subjective as well as objective
evaluations have demonstrated the feasibility of image-based personality test
in limited questions
Noise, regularizers, and unrealizable scenarios in online learning from restricted training sets
We study the dynamics of on-line learning in multilayer neural networks where training examples are sampled with repetition and where the number of examples scales with the number of network weights. The analysis is carried out using the dynamical replica method aimed at obtaining a closed set of coupled equations for a set of macroscopic variables from which both training and generalization errors can be calculated. We focus on scenarios whereby training examples are corrupted by additive Gaussian output noise and regularizers are introduced to improve the network performance. The dependence of the dynamics on the noise level, with and without regularizers, is examined, as well as that of the asymptotic values obtained for both training and generalization errors. We also demonstrate the ability of the method to approximate the learning dynamics in structurally unrealizable scenarios. The theoretical results show good agreement with those obtained by computer simulations
Sex differences in colon cancer metabolism reveal a novel subphenotype
Women have a lower incidence of colorectal cancer (CRC) than men, however, they have a higher incidence of right-sided colon cancer (RCC). This is of concern as patients with RCC have the poorest clinical outcomes among all CRC patients. Aberrant metabolism is a known hallmark and therapeutic target for cancer. We propose that metabolic subphenotypes exist between CRCs due to intertumoral molecular and genomic variation, and differences in environmental milieu of the colon which vary between the sexes. Metabolomics analysis of patient colon tumors (n = 197) and normal tissues (n = 39) revealed sex-specific metabolic subphenotypes dependent on anatomic location. Tumors from women with RCC were nutrient-deplete, showing enhanced energy production to fuel asparagine synthesis and amino acid uptake. The clinical importance of our findings were further investigated in an independent data set from The Cancer Genomic Atlas, and demonstrated that high asparagine synthetase (ASNS) expression correlated with poorer survival for women. This is the first study to show a unique, nutrient-deplete metabolic subphenotype in women with RCC, with implications for tumor progression and outcomes in CRC patients
Annealing schedule from population dynamics
We introduce a dynamical annealing schedule for population-based optimization
algorithms with mutation. On the basis of a statistical mechanics formulation
of the population dynamics, the mutation rate adapts to a value maximizing
expected rewards at each time step. Thereby, the mutation rate is eliminated as
a free parameter from the algorithm.Comment: 6 pages RevTeX, 4 figures PostScript; to be published in Phys. Rev.
Genetic algorithm dynamics on a rugged landscape
The genetic algorithm is an optimization procedure motivated by biological
evolution and is successfully applied to optimization problems in different
areas. A statistical mechanics model for its dynamics is proposed based on the
parent-child fitness correlation of the genetic operators, making it applicable
to general fitness landscapes. It is compared to a recent model based on a
maximum entropy ansatz. Finally it is applied to modeling the dynamics of a
genetic algorithm on the rugged fitness landscape of the NK model.Comment: 10 pages RevTeX, 4 figures PostScrip
Tumor tissue-specific biomarkers of colorectal cancer by anatomic location and stage
The progress in the discovery and validation of metabolite biomarkers for the detection of colorectal cancer (CRC) has been hampered by the lack of reproducibility between study cohorts. The majority of discovery-phase biomarker studies have used patient blood samples to identify disease-related metabolites, but this pre-validation phase is confounded by non-specific disease influences on the metabolome. We therefore propose that metabolite biomarker discovery would have greater success and higher reproducibility for CRC if the discovery phase was conducted in tumor tissues, to find metabolites that have higher specificity to the metabolic consequences of the disease, that are then validated in blood samples. This would thereby eliminate any non-tumor and/or body response effects to the disease. In this study, we performed comprehensive untargeted metabolomics analyses on normal (adjacent) colon and tumor tissues from CRC patients, revealing tumor tissue-specific biomarkers (n = 39/group). We identified 28 highly discriminatory tumor tissue metabolite biomarkers of CRC by orthogonal partial least-squares discriminant analysis (OPLS-DA) and univariate analyses (VIP > 1.5, p 0.96, using various models. We further identified five biomarkers that were specific to the anatomic location of tumors in the colon (n = 236). The combination of these five metabolites (S-adenosyl-L-homocysteine, formylmethionine, fucose 1-phosphate, lactate, and phenylalanine) demonstrated high differentiative capability for left- and right-sided colon cancers at stage I by internal cross-validation (AUC = 0.804, 95% confidence interval, CI 0.670–0.940). This study thus revealed nine discriminatory biomarkers of CRC that are now poised for external validation in a future independent cohort of samples. We also discovered a discrete metabolic signature to determine the anatomic location of the tumor at the earliest stage, thus potentially providing clinicians a means to identify individuals that could be triaged for additional screening regimens
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Diaries For Intensive Care Unit Survivors (discuss): Perspectives Of Patients And Family Members Regarding Psychological Support
Rationale
Diaries summarising care in the intensive care unit (ICU) have been incorporated into routine practice in some countries, although diary format, content, timing and method of delivery vary. The evidence and underpinning theory to support diary use is limited and uptake by patients and family members is infrequent raising questions of acceptance and generalisability. The purpose of this study was to elicit preferences of ICU survivors and their family members regarding diaries and other psychological support mechanisms, specifically if they wish to receive a diary or alternative psychological support material, what content they would like and preferred process and timing for receiving this information.
Methods
Patients in a general ICU for ≥3 days and their family members were invited to participate in this prospective exploratory study. Semi-structured interviews were conducted 3-5 months after ICU discharge via phone or in person. Interviews were transcribed verbatim and thematic analysis was conducted, with codes developed inductively using an iterative process and agreement on themes negotiated by team members.
Results
Forty-one survivors of critical illness and 26 family members consented to participation. Patients were usually male (63%), aged 50±18 years and stayed in ICU for median 8.5 (IQR 5.3-12.6) days. Patients and family members raised similar themes, although with a diverse range of opinion related to each aspect of ICU diary use. Considerations included: 1) memory and recall with some respondents wanting to know detail while others were either not curious or had no desire to be reminded of their ICU stay; 2) level of detail ranging from a comprehensive summary of clinical activities to a predominantly personal record of the experience; 3) the desire to develop shared memory of ICU and for the patient to understand what the family had been through; 4) timing of provision of diary from soon after the patient woke to months later; 5) concerns regarding the workload of staff to contribute to the diary; 6) potential to exacerbate or alternatively relieve stress; 7) uncertainty in regard to writing in diary as the patient may not survive; 8) ownership of the diary resting with the patient.
Conclusions
Common themes have been expressed by participants, although views regarding these themes were extremely diverse. Development of future interventions to aid psychological recovery must take into account these variable views to minimise the potential for causing distress to some survivors of critical illness and/or their family members whilst helping others
Globally optimal on-line learning rules for multi-layer neural networks
We present a method for determining the globally optimal on-line learning rule for a soft committee machine under a statistical mechanics framework. This rule maximizes the total reduction in generalization error over the whole learning process. A simple example demonstrates that the locally optimal rule, which maximizes the rate of decrease in generalization error, may perform poorly in comparison
Analytical and numerical investigation of escape rate for a noise driven bath
We consider a system-reservoir model where the reservoir is modulated by an
external noise. Both the internal noise of the reservoir and the external noise
are stationary, Gaussian and are characterized by arbitrary decaying
correlation functions. Based on a relation between the dissipation of the
system and the response function of the reservoir driven by external noise we
numerically examine the model using a full bistable potential to show that one
can recover the turn-over features of the usual Kramers' dynamics when the
external noise modulates the reservoir rather than the system directly. We
derive the generalized Kramers' rate for this nonequilibrium open system. The
theoretical results are verified by numerical simulation.Comment: Revtex, 25 pages, 5 figures. To appear in Phys. Rev.
The Herschel Planetary Nebula Survey (HerPlaNS) I. Data Overview and Analysis Demonstration with NGC 6781
This is the first of a series of investigations into far-IR characteristics
of 11 planetary nebulae (PNs) under the Herschel Space Observatory Open Time 1
program, Herschel Planetary Nebula Survey (HerPlaNS). Using the HerPlaNS data
set, we look into the PN energetics and variations of the physical conditions
within the target nebulae. In the present work, we provide an overview of the
survey, data acquisition and processing, and resulting data products. We
perform (1) PACS/SPIRE broadband imaging to determine the spatial distribution
of the cold dust component in the target PNs and (2) PACS/SPIRE
spectral-energy-distribution (SED) and line spectroscopy to determine the
spatial distribution of the gas component in the target PNs. For the case of
NGC 6781, the broadband maps confirm the nearly pole-on barrel structure of the
amorphous carbon-richdust shell and the surrounding halo having temperatures of
26-40 K. The PACS/SPIRE multi-position spectra show spatial variations of
far-IR lines that reflect the physical stratification of the nebula. We
demonstrate that spatially-resolved far-IR line diagnostics yield the (T_e,
n_e) profiles, from which distributions of ionized, atomic, and molecular gases
can be determined. Direct comparison of the dust and gas column mass maps
constrained by the HerPlaNS data allows to construct an empirical gas-to-dust
mass ratio map, which shows a range of ratios with the median of 195+-110. The
present analysis yields estimates of the total mass of the shell to be 0.86
M_sun, consisting of 0.54 M_sun of ionized gas, 0.12 M_sun of atomic gas, 0.2
M_sun of molecular gas, and 4 x 10^-3 M_sun of dust grains. These estimates
also suggest that the central star of about 1.5 M_sun initial mass is
terminating its PN evolution onto the white dwarf cooling track.Comment: 27 pages, 16 figures, accepted for publication in A&
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