Entropy Message Passing

The paper proposes a new message passing algorithm for cycle-free factor graphs. The proposed "entropy message passing" (EMP) algorithm may be viewed as sum-product message passing over the entropy semiring, which has previously appeared in automata theory. The primary use of EMP is to compute the entropy of a model. However, EMP can also be used to compute expressions that appear in expectation maximization and in gradient descent algorithms.Comment: 5 pages, 1 figure, to appear in IEEE Transactions on Information Theor

Towards recognizing "cool": can end users help computer vision recognize subjective attributes of objects in images?

Recent computer vision approaches are aimed at richer image interpretations that extend the standard recognition of objects in images (e.g., cars) to also recognize object attributes (e.g., cylindrical, has-stripes, wet). However, the more idiosyncratic and abstract the notion of an object attribute (e.g., cool car), the more challenging the task of attribute recognition. This paper considers whether end users can help vision algorithms recognize highly idiosyncratic attributes, referred to here as subjective attributes. We empirically investigated how end users recognized three subjective attributes of carscool, cute, and classic. Our results suggest the feasibility of vision algorithms recognizing subjective attributes of objects, but an interactive approach beyond standard supervised learning from labeled training examples is needed

Anesthesia and cognitive performance in children: No evidence for a causal relationship

* Both authors contributed evenly to the manuscript Recent findings of an association between anesthesia administration in the first three years of life and later learning disabilities have created concerns that anesthesia has neurotoxic effects on synaptogenesis, causing later learning problems. An alternative hypothesis is that those children who are likely to undergo surgery early in life have significant medical problems that are associated with a vulnerability to learning disabilities. These two hypotheses were evaluated in a monozygotic concordant–discordant twin design. Data on anesthesia administration and learning abilities and disabilities were available for 1,143 monozygotic twin pairs (56 % female) from the Netherlands Twin Registry. Parents of the twins reported on anesthesia use before age 3 and again between ages 3 and 12 years. Near age 12, educational achievement and cognitive problems were assessed with standardized tests and teacher ratings. Results showed that twins who were exposed to anesthesia before age 3 had significantly lower educational achievement scores and significantly more cognitive problems than twins not exposed to anesthesia. However, there was one important exception: the unexposed co-twin from discordant pairs did not differ from their exposed cotwin. Thus, there is no evidence for a causal relationship between anesthesia administration and later learning-related outcomes in this sample. Rather, there is evidence for early anesthesia being a marker of an individual’s vulnerability for later learning problems, regardless of their exposure to anesthesia

Understanding Scanning Tunneling Microscopy Contrast Mechanisms on Metal Oxides: A Case Study

Cataloged from PDF version of article.A comprehensive analysis of contrast formation mechanisms in scanning tunneling microscopy (STM) experiments on a metal oxide surface is presented with the oxygen-induced (2√2 √2)R45 missing row reconstruction of the Cu(100) surface as a model system. Density functional theory and electronic transport calculations were combined to simulate the STM imaging behavior of pure and oxygen-contaminated metal tips with structurally and chemically different apexes while systematically varying bias voltage and tip sample distance. The resulting multiparameter database of computed images was used to conduct an extensive comparison with experimental data. Excellent agreement was attained for a large number of cases, suggesting that the assumed model tips reproduce most of the commonly encountered contrast-determining effects. Specifically, we find that depending on the bias voltage polarity, copper-terminated tips allow selective imaging of two structurally distinct surface Cu sites, while oxygenterminated tips show complex contrasts with pronounced asymmetry and tip sample distance dependence. Considering the structural and chemical stability of the tips reveals that the copper-terminated apexes tend to react with surface oxygen at small tip sample distances. In contrast, oxygenterminated tips are considerably more stable, allowing exclusive surface oxygen imaging at small tip sample distances. Our results provide a conclusive understanding of fundamental STM imaging mechanisms, thereby providing guidelines for experimentalists to achieve chemically selective imaging by properly selecting imaging parameters

Lipidomics Provides New Insight into Pathogenesis and Therapeutic Targets of the Ischemia-Reperfusion Injury

Lipids play an essential role in both tissue protection and damage. Tissue ischemia creates anaerobic conditions in which enzyme inactivation occurs, and reperfusion can initiate oxidative stress that leads to harmful changes in membrane lipids, the formation of aldehydes, and chain damage until cell death. The critical event in such a series of harmful events in the cell is the unwanted accumulation of fatty acids that leads to lipotoxicity. Lipid analysis provides additional insight into the pathogenesis of ischemia/reperfusion (I/R) disorders and reveals new targets for drug action. The profile of changes in the composition of fatty acids in the cell, as well as the time course of these changes, indicate both the mechanism of damage and new therapeutic possibilities. A therapeutic approach to reperfusion lipotoxicity involves attenuation of fatty acids overload, i.e., their transport to adipose tissue and/or inhibition of the adverse effects of fatty acids on cell damage and death. The latter option involves using PPAR agonists and drugs that modulate the transport of fatty acids via carnitine into the interior of the mitochondria or the redirection of long-chain fatty acids to peroxisomes

Alkali activation of dif ferent type of ash as a production of combustion process

Presented study deals with the final struc ture and radiological properties of different fly-ash based geopolymers. Lig nite fly-ash (lignite Kolubara – Ser bia) and wood fly ash were obtained in combustion process together with commercial fly-ash. Synthesis of the geopolymers was con ducted by mixing fly-ash, sodium silicate solution, NaOH and water. The sam ples were strength ened 60 °C for 48 hours af ter stay ing at room temperature in covering mold for 24 hours. The X-ray dif frac tion, Fou rier trans form in fra red and SAM mea sure ments were conducted on the sam ples af ter 28 days of geopolymerization pro cess. The X-ray dif frac tion measurements of lignite fly-ash sam ples show anhydrite as the main constituent, while wood fly-ash samples consist of cal cite, albite and gypsum minerals. Besides determination of physicochemical properties, the aim of this study was radiological characterization of lignite fly-ash, wood fly-ash and the obtained geopolymer products. Ac tiv ity con cen tra tion of 40 K and radionuclides from the 238 U and 232 Th decay series, in ash sam ples and fly-ash based geopolymers, were determined by means of gamma-ray spectrometry, and the absorbed dose rate, D, and the annual effective dose rate, E, were calcu lated in accordance with the UNSCEAR 2000 report

Simultaneous measurement of multiple independent atomic-scale Interactions using scanning probe microscopy: data interpretation and the effect of cross-talk

Cataloged from PDF version of article.In high-resolution scanning probe microscopy, it is becoming increasingly common to simultaneously record multiple channels representing different tip-sample interactions to collect complementary information about the sample surface. A popular choice involves simultaneous scanning tunneling microscopy (STM) and noncontact atomic force microscopy (NC-AFM) measurements, which are thought to reflect the chemical and electronic properties of the sample surface. With surface-oxidized Cu(100) as an example, we investigate whether atomic-scale information on chemical interactions can be reliably extracted from frequency shift maps obtained while using the tunneling current as the feedback parameter. Ab initio calculations of interaction forces between specific tip apexes and the surface are utilized to compare experiments with theoretical expectations. The examination reveals that constant-current operation may induce a noticeable influence of topography-feedback-induced cross-talk on the frequency shift data, resulting in misleading interpretations of local chemical interactions on the surface. Consequently, the need to apply methods such as 3D-AFM is emphasized when accurate conclusions about both the local charge density near the Fermi level, as provided by the STM channel, and the site-specific strength of tip-sample interactions (NC-AFM channel) are desired. We conclude by generalizing to the case where multiple atomic-scale interactions are being probed while only one of them is kept constant

Selenotriapine – An isostere of the most studied thiosemicarbazone with pronounced pro-apoptotic activity, low toxicity and ability to challenge phenotype reprogramming of 3-D mammary adenocarcinoma tumors

Triapine, the most studied α-N-heterocyclic thiosemicarbazone, revealed potent activity against advanced leukemia, but was ineffective against a variety of solid tumors. Moreover, methemoglobinemia, which is a side effect of triapine administration, may limits all clinical application. To enhance anticancer activity and reduce side effects, we applied an isosteric replacement of sulfur to selenium atom was performed by synthesis and characterization of selenium triapine analog, 3-aminopyridine-2-carboxaldehyde selenosemicarbazone (selenotriapine). Compared to triapine, selenotriapine revealed superior pro-apoptotic activity with activation of intrinsic apoptotic pathway in both human monocytic leukemia (THP-1) and mammary adenocarcinoma (MCF-7) cell lines. For MCF-7 2-D cultures, selenotriapine induced notable increase in mitochondrial superoxide radical generation and dissipation of mitochondrial transmembrane potential. A significant delay in growth of MCF-7 spheroids (3-D culture) was accompanied by phenotypic stem cell reprogramming (Oct-4 expression). Additionally, selenotriapine demonstrated a very low toxicity profile as compared to triapine, confirmed over alleviated extent of methemoglobin formation and higher IC50 value in brine shrimp cytotoxicity assay