Long-range correlations and fractal dynamics in C. elegans: changes with aging and stress

Reduced motor control is one of the most frequent features associated with aging and disease. Nonlinear and fractal analyses have proved to be useful in investigating human physiological alterations with age and disease. Similar findings have not been established for any of the model organisms typically studied by biologists, though. If the physiology of a simpler model organism displays the same characteristics, this fact would open a new research window on the control mechanisms that organisms use to regulate physiological processes during aging and stress. Here, we use a recently introduced animal tracking technology to simultaneously follow tens of Caenorhabdits elegans for several hours and use tools from fractal physiology to quantitatively evaluate the effects of aging and temperature stress on nematode motility. Similarly to human physiological signals, scaling analysis reveals long-range correlations in numerous motility variables, fractal properties in behavioral shifts, and fluctuation dynamics over a wide range of timescales. These properties change as a result of a superposition of age and stress-related adaptive mechanisms that regulate motility.Comment: Accepted for publication in Physical Review

Beam Scraping to detect and remove Halo in LHC Injection

Fast scrapers are installed in the SPS to detect and remove beam halo before extraction of beams to the LHC, to minimize the probability for quenching of superconducting magnets in the LHC. We shortly describe the current system and then focus on our recent work, which aims at providing a system which can be used as operational tool for standard LHC injection. A new control application was written and tested with the beam. We describe the current status and results and compare these with detailed simulations

A computational model of aesthetic value

People constantly evaluate what they see, and these evaluations determine their choices from small (Where do I look next?) to large (Where do I want to live?). The pleasure associated with a sensory experience, namely its aesthetic value, is perhaps the most frequent and important evaluation. Yet, we have a poor understanding of how sensory experiences gain aesthetic value. We propose a model of aesthetic value that is based on the premise that observers maintain and adapt the states of their cognitive-sensory system in a way that allows them to process stimuli effectively in both the present and the future. Two interlinked components generate value: stimulus processing fluency and the change in fluency with regard to likely future stimuli. In our model, processing fluency is quantified precisely as the likelihood of the stimulus given an observer's state and constitutes immediate sensory reward. The change in fluency with which likely future stimuli will be processed, quantified by the change in the average likelihood of expected future stimuli, constitutes the reward of learning. Simulations show that a simple version of our model can account for empirical data on the effects of exposure, complexity, and symmetry on aesthetic value judgments. Its application offers insight as to how mechanisms that improve long-term processing efficiency give rise to aesthetic value judgments

Discounting the effect of memory on repeated measures of beauty judgment

The intrinsic variance of beauty judgment is key to modeling beauty ratings. However, in repeated measures of beauty, observers surely make use of what they remember. To test how memory contributes to repeated beauty ratings, we asked participants to rate 75 arbitrarily named images (e.g., Fred). Initially, participants rated (1 to 7) how much beauty they felt from looking at a named image. Then participants completed two conditions. In the memory condition, participants saw only the name of an image and were asked to remember the image corresponding to that name and rate how much beauty they felt. In the repeat condition, they once again rated how much beauty they felt from looking at a named image. Lastly, in a memory check, participants tried to select which image was associated with a name. Only considering the correctly remembered trials (60%), we calculated the distribution of the differences between the initial beauty rating and that from either the memory condition or the repeat condition. The variance for the memory condition was more than double that of the repeat condition. Likewise, the initial beauty ratings predicted 84% of the variance in the repeat ratings but only 30% of the variance in the memory ratings. Cue combination studies report that observers typically combine cues by the optimal Bayesian rule: The combined reliability is the sum of the separate reliabilities for each cue, where reliability is one over variance. Assuming optimal combination of memory and immediate-perception judgment, we can discount the contribution of memory to estimate the variance of the immediate-perception judgment. Thus, in our paradigm the 0.83 variance of the repeated beauty rating corresponds to a 0.97 immediate-perception judgment variance (without memory). Overall, since there also was no significant difference in means, our results indicate that memory contributes little to repeated beauty ratings

Serotonergic signalling suppresses ataxin 3 aggregation and neurotoxicity in animal models of Machado-Joseph disease

Polyglutamine diseases are a class of dominantly inherited neurodegenerative disorders for which there is no effective treatment. Here we provide evidence that activation of serotonergic signalling is beneficial in animal models of Machado-Joseph disease. We identified citalopram, a selective serotonin reuptake inhibitor, in a small molecule screen of FDA-approved drugs that rescued neuronal dysfunction and reduced aggregation using a Caenorhabditis elegans model of mutant ataxin 3-induced neurotoxicity. MOD-5, the C. elegans orthologue of the serotonin transporter and cellular target of citalopram, and the serotonin receptors SER-1 and SER-4 were strong genetic modifiers of ataxin 3 neurotoxicity and necessary for therapeutic efficacy. Moreover, chronic treatment of CMVMJD135 mice with citalopram significantly reduced ataxin 3 neuronal inclusions and astrogliosis, rescued diminished body weight and strikingly ameliorated motor symptoms. These results suggest that small molecule modulation of serotonergic signalling represents a promising therapeutic target for Machado-Joseph disease.This work was supported by Fundação para a Ciência e Tecnologia (FCT) and COMPETE through the projects ‘[PTDC/SAU-GMG/112617/2009] (to P.M.) and [EXPL/ BIM-MEC/0239/2012] (to A.T.C.)’, by National Ataxia foundation (to P.M.), by Ataxia UK (to P.M.), by National Institutes of Health (NIH) ‘[GM038109, GM081192, AG026647, and NS047331] (to R.I.M.)’, by The Chicago Biomedical Consortium (to R.I.M.) and by the Ellison Medical Foundation (to R.I.M.). A.T.C., A.J., S.E., L.S.S., C.B., S.D.S., A.S.F. and A.N.C. were supported by the FCT individual fellowships SFRH/BPD/79469/2011, SFRH/BD/76613/2011, SFRH/BD/78554/2011, SFRH/BD/ 84650/2012, SFRH/BPD/74452/2010, SFRH/BD/78388/ 2011, SFRH/BPD/91562/2012 and SFRH/BD/51059/2010, respectively. FCT fellowships are co-financed by POPH, QREN, Governo da República Portuguesa and EU/FSE.info:eu-repo/semantics/publishedVersio

Simplicity in Complexity : Explaining Visual Complexity using Deep Segmentation Models

The complexity of visual stimuli plays an important role in many cognitive phenomena, including attention, engagement, memorability, time perception and aesthetic evaluation. Despite its importance, complexity is poorly understood and ironically, previous models of image complexity have been quite complex. There have been many attempts to find handcrafted features that explain complexity, but these features are usually dataset specific, and hence fail to generalise. On the other hand, more recent work has employed deep neural networks to predict complexity, but these models remain difficult to interpret, and do not guide a theoretical understanding of the problem. Here we propose to model complexity using segment-based representations of images. We use state-of-the-art segmentation models, SAM and FC-CLIP, to quantify the number of segments at multiple granularities, and the number of classes in an image respectively. We find that complexity is well-explained by a simple linear model with these two features across six diverse image-sets of naturalistic scene and art images. This suggests that the complexity of images can be surprisingly simple

A Comparative Survey of Leguminous Plants as Sources of the Isoflavones, Genistein and Daidzein: Implications for Human Nutrition and Health

Over 80 taxa of mostly agriculturally important legumes were surveyed as sources of the metabolites, genistein and daidzein. Remarkably high concentrations (over 2 g · kg–1 dry weight) of the anticancer metabolite, genistein, were found in the leaves of Psoralea corylifolia (Indian bread root). All other legumes, with the exception of fermented soybean miso, had genistein levels <400 mg · kg–1 dry weight. Concentrations of over 1 g · kg–1 dry weight and 0.95 g · kg–1 dry weight of the anticancer metabolite, daidzein, were found in the stems of the fava bean (Vicia faba) and roots of kudzu vine (Pueraria lobata)' respectively. From this survey, our results indicate that the legumes, lupine (Lupinus spp.), fava bean, (Vicia faha), soybeans (Glycine max), kudzu (Pueraria lobata), and psoralea (Psoralea corylifolia), are excellent food sources for both genistein and daidzein. Miso, a fermented soybean product, is also a rich source of both isoflavones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63131/1/acm.1997.3.7.pd