1,768 research outputs found

    Constraints on modified gravity from Planck 2015: when the health of your theory makes the difference

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    We use the effective field theory of dark energy (EFT of DE) formalism to constrain dark energy models belonging to the Horndeski class with the recent Planck 2015 CMB data. The space of theories is spanned by a certain number of parameters determining the linear cosmological perturbations, while the expansion history is set to that of a standard Λ\LambdaCDM model. We always demand that the theories be free of fatal instabilities. Additionally, we consider two optional conditions, namely that scalar and tensor perturbations propagate with subliminal speed. Such criteria severely restrict the allowed parameter space and are thus very effective in shaping the posteriors. As a result, we confirm that no theory performs better than Λ\LambdaCDM when CMB data alone are analysed. Indeed, the healthy dark energy models considered here are not able to reproduce those phenomenological behaviours of the effective Newton constant and gravitational slip parameters that, according to previous studies, best fit the data.Comment: 21 pages, 8 figures. Added Mu-Sigma plane in Fig.7 plus some changes in the text with respect to the previous version. This is an author-created un-copyedited version of the article published in JCAP. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscrip

    Data mining and fusion

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    Signal processing for molecular and cellular biological physics:an emerging field

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    Recent advances in our ability to watch the molecular and cellular processes of life in action-such as atomic force microscopy, optical tweezers and Forster fluorescence resonance energy transfer-raise challenges for digital signal processing (DSP) of the resulting experimental data. This article explores the unique properties of such biophysical time series that set them apart from other signals, such as the prevalence of abrupt jumps and steps, multi-modal distributions and autocorrelated noise. It exposes the problems with classical linear DSP algorithms applied to this kind of data, and describes new nonlinear and non-Gaussian algorithms that are able to extract information that is of direct relevance to biological physicists. It is argued that these new methods applied in this context typify the nascent field of biophysical DSP. Practical experimental examples are supplied

    Factorial Ecology: Methodological Refinements Using 1960 Omaha Data

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    American sociologists have had an abiding interest in the causes and consequences of urban phenomena. Afterall, the emergent American metropolis has a certain lure to it, which is no doubt engendered by its marked cultural and social heterogeneity, and fluid spatial and social mobility. Then too, urban problems are highly visible problems; declining and dilapidated areas, poverty pockets , crime, etc., all command attention from diverse agencies and segments of the public

    Mitmekesiste bioloogiliste andmete ĂŒhendamine ja analĂŒĂŒs

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    VĂ€itekirja elektrooniline versioon ei sisalda publikatsiooneTĂ€nu tehnoloogiate arengule on bioloogiliste andmete maht viimastel aastatel mitmekordistunud. Need andmed katavad erinevaid bioloogia valdkondi. Piirdudes vaid ĂŒhe andmestikuga saab bioloogilisi protsesse vĂ”i haigusi uurida vaid ĂŒhest aspektist korraga. SeetĂ”ttu on tekkinud ĂŒha suurem vajadus masinĂ”ppe meetodite jĂ€rele, mis aitavad kombineerida eri valdkondade andmeid, et uurida bioloogilisi protsesse tervikuna. Lisaks on nĂ”udlus usaldusvÀÀrsete haigusspetsiifiliste andmestike kogude jĂ€rele, mis vĂ”imaldaks vastavaid analĂŒĂŒse efektiivsemalt lĂ€bi viia. KĂ€esolev vĂ€itekiri kirjeldab, kuidas rakendada masinĂ”ppel pĂ”hinevaid integratsiooni meetodeid erinevate bioloogiliste kĂŒsimuste uurimiseks. Me nĂ€itame kuidas integreeritud andmetel pĂ”hinev analĂŒĂŒs vĂ”imaldab paremini aru saada bioloogilistes protsessidest kolmes valdkonnas: Alzheimeri tĂ”bi, toksikoloogia ja immunoloogia. Alzheimeri tĂ”bi on vanusega seotud neurodegeneratiivne haigus millel puudub efektiivne ravi. VĂ€itekirjas nĂ€itame, kuidas integreerida erinevaid Alzheimeri tĂ”ve spetsiifilisi andmestikke, et moodustada heterogeenne graafil pĂ”hinev Alzheimeri spetsiifiline andmestik HENA. SeejĂ€rel demonstreerime sĂŒvaĂ”ppe meetodi, graafi konvolutsioonilise tehisnĂ€rvivĂ”rgu, rakendamist HENA-le, et leida potentsiaalseid haigusega seotuid geene. Teiseks uurisime kroonilist immuunpĂ”letikulist haigust psoriaasi. Selleks kombineerisime patsientide verest ja nahast pĂ€rinevad laboratoorsed mÔÔtmised kliinilise infoga ning integreerisime vastavad analĂŒĂŒside tulemused tuginedes valdkonnaspetsiifilistel teadmistel. Töö viimane osa keskendub toksilisuse testimise strateegiate edasiarendusele. Toksilisuse testimine on protsess, mille kĂ€igus hinnatakse, kas uuritavatel kemikaalidel esineb organismile kahjulikke toimeid. See on vajalik nĂ€iteks ravimite ohutuse hindamisel. Töös me tuvastasime sarnase toimemehhanismiga toksiliste ĂŒhendite rĂŒhmad. Lisaks arendasime klassifikatsiooni mudeli, mis vĂ”imaldab hinnata uute ĂŒhendite toksilisust.A fast advance in biotechnological innovation and decreasing production costs led to explosion of experimental data being produced in laboratories around the world. Individual experiments allow to understand biological processes, e.g. diseases, from different angles. However, in order to get a systematic view on disease it is necessary to combine these heterogeneous data. The large amounts of diverse data requires building machine learning models that can help, e.g. to identify which genes are related to disease. Additionally, there is a need to compose reliable integrated data sets that researchers could effectively work with. In this thesis we demonstrate how to combine and analyze different types of biological data in the example of three biological domains: Alzheimer’s disease, immunology, and toxicology. More specifically, we combine data sets related to Alzheimer’s disease into a novel heterogeneous network-based data set for Alzheimer’s disease (HENA). We then apply graph convolutional networks, state-of-the-art deep learning methods, to node classification task in HENA to find genes that are potentially associated with the disease. Combining patient’s data related to immune disease helps to uncover its pathological mechanisms and to find better treatments in the future. We analyse laboratory data from patients’ skin and blood samples by combining them with clinical information. Subsequently, we bring together the results of individual analyses using available domain knowledge to form a more systematic view on the disease pathogenesis. Toxicity testing is the process of defining harmful effects of the substances for the living organisms. One of its applications is safety assessment of drugs or other chemicals for a human organism. In this work we identify groups of toxicants that have similar mechanism of actions. Additionally, we develop a classification model that allows to assess toxic actions of unknown compounds.https://www.ester.ee/record=b523255
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