Browsing by Subject "NOISE"

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  • Feher, O.; Juvela, M.; Lunttila, T.; Montillaud, J.; Ristorcelli, I.; Zahorecz, S.; Toth, L. V. (2017)
    Context. The physical state of cold cloud clumps has a great impact on the process and efficiency of star formation and the masses of the forming stars inside these objects. The sub-millimetre survey of the Planck space observatory and the far-infrared follow-up mapping of the Herschel space telescope provide an unbiased, large sample of these cold objects. Aims. We have observed (CO)-C-12(1-0) and (CO)-C-13(1-0) emission in 35 high-density clumps in 26 Herschel fields sampling different environments in the Galaxy. Here, we aim to derive the physical properties of the objects and estimate their gravitational stability. Methods. The densities and temperatures of the clumps were calculated from both the dust continuum and the molecular line data. Kinematic distances were derived using (CO)-C-13(1-0) line velocities to verify previous distance estimates and the sizes and masses of the objects were calculated by fitting 2D Gaussian functions to their optical depth distribution maps on 250 mu m. The masses and virial masses were estimated assuming an upper and lower limit on the kinetic temperatures and considering uncertainties due to distance limitations. Results. The derived excitation temperatures are between 8.5-19.5 K, and for most clumps between 10 15 K, while the Herschel-derived dust colour temperatures are more uniform, between 12 16 K. The sizes (0.1-3 pc), (CO)-C-13 column densities (0.5-44 x 10(15) cm(-2)) and masses (from less than 0.1 M-circle dot to more than 1500 M-circle dot) of the objects all span broad ranges. We provide new kinematic distance estimates, identify gravitationally bound or unbound structures and discuss their nature. Conclusions. The sample contains objects on a wide scale of temperatures, densities and sizes. Eleven gravitationally unbound clumps were found, many of them smaller than 0.3 pc, but large, parsec-scale clouds with a few hundred solar masses appear as well. Colder clumps have generally high column densities but warmer objects appear at both low and higher column densities. The clump column densities derived from the line and dust observations correlate well, but are heavily affected by uncertainties of the dust properties, varying molecular abundances and optical depth effects.
  • Kauppi, Jukka-Pekka; Pajula, Juha; Tohka, Jussi (2014)
    In the inter-subject correlation (ISC) based analysis of the functional magnetic resonance imaging (fMRI) data, the extent of shared processing across subjects during the experiment is determined by calculating correlation coefficients between the fMRI time series of the subjects in the corresponding brain locations. This implies that ISC can be used to analyze fMRI data without explicitly modeling the stimulus and thus ISC is a potential method to analyze fMRI data acquired under complex naturalistic stimuli. Despite of the suitability of ISC based approach to analyze complex fMRI data, no generic software tools have been made available for this purpose, limiting a widespread use of ISC based analysis techniques among neuroimaging community. In this paper, we present a graphical user interface (GUI) based software package, ISC Toolbox, implemented in Matlab for computing various ISC based analyses. Many advanced computations such as comparison of ISCs between different stimuli, time window ISC, and inter-subject phase synchronization are supported by the toolbox. The analyses are coupled with resampling based statistical inference. The ISC based analyses are data and computation intensive and the ISC toolbox is equipped with mechanisms to execute the parallel computations in a cluster environment automatically and with an automatic detection of the cluster environment in use. Currently, SGE-based (Oracle Grid Engine, Son of a Grid Engine, or Open Grid Scheduler) and Slurm environments are supported. In this paper, we present a detailed account on the methods behind the ISC Toolbox, the implementation of the toolbox and demonstrate the possible use of the toolbox by summarizing selected example applications. We also report the computation time experiments both using a single desktop computer and two grid environments demonstrating that parallelization effectively reduces the computing time.
  • Pentikäinen, Emmi; Kimppa, Lilli; Makkonen, Tommi; Putkonen, Mikko Tapani; Pitkäniemi, Anni; Salakka, Ilja Juhana; Paavilainen, Petri; Tervaniemi, Mari; Särkämö, Teppo (2022)
    Aging is accompanied by difficulties in auditory information processing, especially in more complex sound environments. Choir singing requires efficient processing of multiple sound features and could, therefore, mitigate the detrimental effects of aging on complex auditory encoding. We recorded auditory event-related potentials during passive listening of sounds in healthy older adult (>= 60 years) choir singers and nonsinger controls. We conducted a complex oddball condition involving encoding of abstract regularities in combinations of pitch and location features, as well as in two simple oddball conditions, in which only either the pitch or spatial location of the sounds was varied. We analyzed change-related mismatch negativity (MMN) and obligatory P1 and N1 responses in each condition. In the complex condition, the choir singers showed a larger MMN than the controls, which also correlated with better performance in a verbal fluency test. In the simple pitch and location conditions, the choir singers had smaller N1 responses compared to the control subjects, whereas the MMN responses did not differ between groups. These results suggest that regular choir singing is associated both with more enhanced encoding of complex auditory regularities and more effective adaptation to simple sound features.
  • Virtanen, Lari S.; Olkkonen, Maria; Saarela, Toni P. (2020)
    Color serves both to segment a scene into objects and background and to identify objects. Although objects and surfaces usually contain multiple colors, humans can readily extract a representative color description, for instance, that tomatoes are red and bananas yellow. The study of color discrimination and identification has a long history, yet we know little about the formation of summary representations of multicolored stimuli. Here, we characterize the human ability to integrate hue information over space for simple color stimuli varying in the amount of information, stimulus size, and spatial configuration of stimulus elements. We show that humans are efficient at integrating hue information over space beyond what has been shown before for color stimuli. Integration depends only on the amount of information in the display and not on spatial factors such as element size or spatial configuration in the range measured. Finally, we find that observers spontaneously prefer a simple averaging strategy even with skewed color distributions. These results shed light on how human observers form summary representations of color and make a link between the perception of polychromatic surfaces and the broader literature of ensemble perception.
  • Quist, Liina-Maija; Nygren, Anja (2019)
    Marine extraction accounts for one third of the world's hydrocarbon production. Several analyses suggest that seismic surveys employed in oil exploration harm marine life; however, their long-term impacts have not been extensively studied. We examine debates between fishers, the oil industry, and governmental authorities over the effects of oil explorations in Tabasco, Mexico. The study employs ideas from historical ontology in tracing the contested production of truth-claims about exploration in the context of scientific uncertainty. It shows how actors, through their different engagements with the sea, and with different degrees of power, frame claims about the relations between exploration and fish. We argue that fishers, through their efforts to "think like fish" produce situated knowledges about the effects of oil exploration. They explain a disappearance of fish by their understanding that seismic surveys disturb fish migration, impair the hearing of fish and cause fish death. Oil company and governmental representatives frame the impacts of oil exploration as insignificant by separating environmental and social dimensions, by isolating individual exploration events, and by arguing that possible effects are transitional. Due to scientific indeterminacy, oil exploration is malleable in the hands of powerful political representations that understate its possible impacts on marine socio-environments.
  • Heikkila, Mikko; Lagerspetz, Eemil; Kaski, Samuel; Shimizu, Kana; Tarkoma, Sasu; Honkela, Antti (NEURAL INFORMATION PROCESSING SYSTEMS (NIPS), 2017)
    Advances in Neural Information Processing Systems
    Many applications of machine learning, for example in health care, would benefit from methods that can guarantee privacy of data subjects. Differential privacy (DP) has become established as a standard for protecting learning results. The standard DP algorithms require a single trusted party to have access to the entire data, which is a clear weakness, or add prohibitive amounts of noise. We consider DP Bayesian learning in a distributed setting, where each party only holds a single sample or a few samples of the data. We propose a learning strategy based on a secure multi-party sum function for aggregating summaries from data holders and the Gaussian mechanism for DP. Our method builds on an asymptotically optimal and practically efficient DP Bayesian inference with rapidly diminishing extra cost.
  • Chacon-Tanarro, A.; Pineda, J. E.; Caselli, P.; Bizzocchi, L.; Gutermuth, R. A.; Mason, B. S.; Gomez-Ruiz, A.; Harju, J.; Devlin, M.; Dicker, S. R.; Mroczkowski, T.; Romero, C. E.; Sievers, J.; Stanchfield, S.; Offner, S.; Sanchez-Argueelles, D. (2019)
    Context. The study of dust emission at millimeter wavelengths is important to shed light on the dust properties and physical structure of pre-stellar cores, the initial conditions in the process of star and planet formation. Aims. Using two new continuum facilities, AzTEC at the Large Millimeter Telescope Alfonso Serrano and MUSTANG-2 at the Green Bank Observatory, we aim to detect changes in the optical properties of dust grains as a function of radius for the well-known pre-stellar core L1544. Methods. We determined the emission profiles at 1.1 and 3.3 mm and examine whether they can be reproduced in terms of the current best physical models for L1544. We also made use of various tools to determine the radial distributions of the density, temperature, and dust opacity in a self-consistent manner. Results. We find that our observations cannot be reproduced without invoking opacity variations. New temperature and density profiles, as well as opacity variations across the core, have been derived with the new data. The opacity changes are consistent with the expected variations between uncoagulated bare grains, toward the outer regions of the core, and grains with thick ice mantles, toward the core center. A simple analytical grain growth model predicts the presence of grains of similar to 3-4 mu m within the central 2000 au for the new density profile.
  • CORE Collaboration; Natoli, P.; Kiiveri, K.; Lindholm, V.; Keihänen, E.; Kurki-Suonio, H.; Väliviita, J. (2018)
    We present an analysis of the main systematic effects that could impact the measurement of CMB polarization with the proposed CORE space mission. We employ timeline to-map simulations to verify that the CORE instrumental set-up and scanning strategy allow us to measure sky polarization to a level of accuracy adequate to the mission science goals. We also show how the CORE observations can be processed to mitigate the level of contamination by potentially worrying systematics, including intensity-to-polarization leakage due to bandpass mismatch, asymmetric main beams, pointing errors and correlated noise. We use analysis techniques that are well validated on data from current missions such as Planck to demonstrate how the residual contamination of the measurements by these effects can be brought to a level low enough not to hamper the scientific capability of the mission, nor significantly increase the overall error budget. We also present a prototype of the CORE photometric calibration pipeline, based on that used for Planck, and discuss its robustness to systematics, showing how CORE can achieve its calibration requirements. While a fine-grained assessment of the impact of systematics requires a level of knowledge of the system that can only be achieved in a future study phase, the analysis presented here strongly suggests that the main areas of concern for the CORE mission can be addressed using existing knowledge, techniques and algorithms.
  • Estonian Biobank Res Team; Trpchevska, Natalia; Freidin, Maxim B.; Broer, Linda; Kaprio, Jaakko; Kettunen, Johannes; Mäkitie, Antti (2022)
    Hearing loss is one of the top contributors to years lived with disability and is a risk factor for dementia. Molecular evidence on the cellular origins of hearing loss in humans is growing. Here, we performed a genome-wide association meta-analysis of clinically diagnosed and self reported hearing impairment on 723,266 individuals and identified 48 significant loci, 10 of which are novel. A large proportion of associations comprised missense variants, half of which lie within known familial hearing loss loci. We used single-cell RNA-sequencing data from mouse cochlea and brain and mapped common-variant genomic results to spindle, root, and basal cells from the stria vascularis, a structure in the cochlea necessary for normal hearing. Our findings indicate the importance of the stria vascularis in the mechanism of hearing impairment, providing future paths for developing targets for therapeutic intervention in hearing loss.
  • Szibor, Annett; Hyvärinen, Petteri; Lehtimäki, Jarmo; Pirvola, Ulla; Ylikoski, Matti; Mäkitie, Antti; Aarnisalo, Antti; Ylikoski, Jukka (2018)
    Conclusion: Music-induced acute acoustic trauma is not inevitably linked to hearing dysfunction as validated by conventional pure tone audiometry. Tinnitus is often in combination with hyperacusis. Our results point at 'silent hearing loss' as the underlying pathology, having afferent nerve terminal damage rather than hair cell loss as the structural correlate. Objectives: Exposure to loud music is one of the most common causes of acute acoustic trauma, which adolescents and teenagers experience by voluntary exposure to loud music of sound levels up to 110 dB(A). Methods: The clinical and psychophysical data of 104 consecutive patients with music-induced hearing disorder (MIHD) were analyzed to construct individual hearing and tinnitus profiles. In all cases, tinnitus was the presenting symptom. Results: Hearing abilities were normal in about two-thirds of the tinnitus patients. Tinnitus was experienced most often as a high-frequency tone (83%). The Tinnitus Handicap Inventory (THI) scores ranged from 0 to 94 with an average score of 43.1. Visual analog scales (VAS) were used to assess tinnitus loudness (average 42.4) and annoyance (average 54.2), and tinnitus awareness was estimated (average 60.3). All VAS values correlated strongly with the THI. Hyperacusis was present in 65% and 71% of the patients reported sleeping disorders.
  • Juvela, Mika; He, Jinhua; Pattle, Katherine; Liu, Tie; Bendo, George; Eden, David J.; Feher, Orsolya; Fich, Michel; Fuller, Gary; Hirano, Naomi; Kim, Kee-Tae; Li, Di; Liu, Sheng-Yuan; Malinen, Johanna; Marshall, Douglas J.; Paradis, Deborah; Parsons, Harriet; Pelkonen, Veli-Matti; Rawlings, Mark G.; Ristorcelli, Isabelle; Samal, Manash R.; Tatematsu, Ken'ichi; Thompson, Mark; Traficante, Alessio; Wang, Ke; Ward-Thompson, Derek; Wu, Yuefang; Yi, Hee-Weon; Yoo, Hyunju (2018)
    Context. Analysis of all-sky Planck submillimetre observations and the IRAS 100 mu m data has led to the detection of a population of Galactic cold clumps. The clumps can be used to study star formation and dust properties in a wide range of Galactic environments. Aims. Our aim is to measure dust spectral energy distribution ( SED) variations as a function of the spatial scale and the wavelength. Methods. We examined the SEDs at large scales using IRAS, Planck, and Herschel data. At smaller scales, we compared JCMT/SCUBA-2 850 mu m maps with Herschel data that were filtered using the SCUBA-2 pipeline. Clumps were extracted using the Fellwalker method, and their spectra were modelled as modified blackbody functions. Results. According to IRAS and Planck data, most fields have dust colour temperatures T-C similar to 14-18K and opacity spectral index values of beta = 1.5-1.9. The clumps and cores identified in SCUBA-2 maps have T similar to 13K and similar beta values. There are some indications of the dust emission spectrum becoming flatter at wavelengths longer than 500 mu m. In fits involving Planck data, the significance is limited by the uncertainty of the corrections for CO line contamination. The fits to the SPIRE data give a median beta value that is slightly above 1.8. In the joint SPIRE and SCUBA-2 850 mu m fits, the value decreases to beta similar to 1.6. Most of the observed T-beta anticorrelation can be explained by noise. Conclusions. The typical submillimetre opacity spectral index fi of cold clumps is found to be similar to 1.7. This is above the values of diffuse clouds, but lower than in some previous studies of dense clumps. There is only tentative evidence of a T-beta anticorrelation and beta decreasing at millimetre wavelengths.
  • Söderqvist, Samuel; Lamminmaki, Satu; Aarnisalo, Antti; Hirvonen, Timo; Sinkkonen, Saku T.; Sivonen, Ville (2021)
    A limiting factor of cochlear implant technology is the spread of electrode-generated intracochlear electrical field (EF) leading to spread of neural excitation (SOE). In this study, we investigated the relation of the spread of the intracochlear EF, assessed via transimpedance matrix (TIM), and SOE. A total of 43 consecutive patients (ages 0.7-82 years; 31.0 +/- 25.7 years, mean +/- SD) implanted with a Cochlear Nucleus CI522 or CI622 cochlear implant with Slim Straight electrode array (altogether 51 ears) were included in the study. Cochlear nerve was visualized for all patients in preoperative imaging and there were no cochlear anomalies in the study sample. The stimulated electrodes were in the basal, middle, and apical parts of the electrode array (electrode numbers 6, 11, and 19, respectively). The stimulation level was 210 CL on average for the TIM measurement and always 230 CL for the SOE measurement. Approximately 90% of the individual TIM and SOE profiles correlated with each other ( p < .05; r = 0.61- 0.99). Also, the widths of the TIM and SOE peaks, computed at 50% of the maximum height, exhibited a weak correlation ( r = 0.39, p = .007). The 50% widths of TIM and SOE were the same only in the apical part of the electrode array; in the basal part SOE was wider than TIM, and in the middle part TIM was wider than SOE ( p < .01 and p = .048, respectively). Within each measurement, TIM 50% widths were different between all three parts of the electrode array, while for SOE, only the basal electrode differed from the middle electrode. Finally, the size of the cochlea and the 50% widths of TIM and SOE had the strongest correlation in the middle part of the electrode array ( r = -0.63, and -0.37, respectively). Our results suggest that there is a correlation between the spread of intracochlear EF and neural SOE at least in the apical part of the electrode array used in this study, and that larger cochleae are associated with more focused TIM and SOE. (c) 2021 Elsevier B.V. All rights reserved.
  • Heikkilä, Jenni; Lonka, Eila; Ahola, Sanna; Meronen, Auli; Tiippana, Kaisa (2017)
    Purpose: Lipreading and its cognitive correlates were studied in school-age children with typical language development and delayed language development due to specific language impairment (SLI). Method: Forty-two children with typical language development and 20 children with SLI were tested by using a word-level lipreading test and an extensive battery of standardized cognitive and linguistic tests. Results: Children with SLI were poorer lipreaders than their typically developing peers. Good phonological skills were associated with skilled lipreading in both typically developing children and in children with SLI. Lipreading was also found to correlate with several cognitive skills, for example, short-term memory capacity and verbal motor skills. Conclusions: Speech processing deficits in SLI extend also to the perception of visual speech. Lipreading performance was associated with phonological skills. Poor lipreading in children with SLI may be, thus, related to problems in phonological processing.
  • Muhammad, Sajjad; Lehecka, Martin; Huhtakangas, Justiina; Jahromi, Behnam Rezai; Niemelä, Mika; Hafez, Ahmad (2019)
    BackgroundNeurosurgeons are vulnerable to additional noise in their natural operating environment. Noise exposure is associated with reduced cognitive function, inability to concentrate, and nervousness. Mediation music provides an opportunity to create a calmer environment which may reduce stress during surgery.MethodsA pilot study was performed to find a suitable task, meditation music of surgeon's choice, and operation noise and to reach a certain level of training. For the main experiment, two neurosurgeons with different microsurgical experience used real operation noise and meditation music with delta waves as mediating music. Each surgeon performed 10 training bypasses (five with noise and five with music) with 16 stitches in each bypass. The total time to complete 16 stitches, a number of unachieved movements (N.U.Ms), length of thread consumed, and distribution of the stitches were quantified from the recorded videos and compared in both groups.ResultsA N.U.Ms were significantly reduced from 10938 with operation room (OR) noise to 38 +/- 13 (p
  • Järvinen, Heikki; Seitola, Teija; Silen, Johan; Räisänen, Jouni (2016)
    A performance expectation is that Earth system models simulate well the climate mean state and the climate variability. To test this expectation, we decompose two 20th century reanalysis data sets and 12 CMIP5 model simulations for the years 1901-2005 of the monthly mean near-surface air temperature using randomised multi-channel singular spectrum analysis (RMSSA). Due to the relatively short time span, we concentrate on the representation of multi-annual variability which the RMSSA method effectively captures as separate and mutually orthogonal spatio-temporal components. This decomposition is a unique way to separate statistically significant quasi-periodic oscillations from one another in high-dimensional data sets. The main results are as follows. First, the total spectra for the two reanalysis data sets are remarkably similar in all timescales, except that the spectral power in ERA-20C is systematically slightly higher than in 20CR. Apart from the slow components related to multi-decadal periodicities, ENSO oscillations with approximately 3.5- and 5-year periods are the most prominent forms of variability in both reanalyses. In 20CR, these are relatively slightly more pronounced than in ERA-20C. Since about the 1970s, the amplitudes of the 3.5- and 5-year oscillations have increased, presumably due to some combination of forced climate change, intrinsic low-frequency climate variability, or change in global observing network. Second, none of the 12 coupled climate models closely reproduce all aspects of the reanalysis spectra, although some models represent many aspects well. For instance, the GFDL-ESM2M model has two nicely separated ENSO periods although they are relatively too prominent as compared with the reanalyses. There is an extensive Supplement and YouTube videos to illustrate the multi-annual variability of the data sets.
  • Smeds, Lina; Takeshita, Daisuke; Turunen, Tuomas; Tiihonen, Jussi Samuli; Westö, Johan; Martyniuk, Nataliia; Seppänen, Aarni Juhani; Ala-Laurila, Petri (2019)
    All sensory information is encoded in neural spike trains. It is unknown how the brain utilizes this neural code to drive behavior. Here, we unravel the decoding rules of the brain at the most elementary level by linking behavioral decisions to retinal output signals in a single-photon detection task. A transgenic mouse line allowed us to separate the two primary retinal outputs, ON and OFF pathways, carrying information about photon absorptions as increases and decreases in spiking, respectively. Wemeasured the sensitivity limit of rods and the most sensitive ON and OFF ganglion cells and correlated these results with visually guided behavior using markerless head and eye tracking. We show that behavior relies only on the ON pathway even when the OFF pathway would allow higher sensitivity. Paradoxically, behavior does not rely on the spike code with maximal information but instead relies on a decoding strategy based on increases in spiking.
  • Aghanim, N.; Chen, X.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kiiveri, K.; Kurki-Suonio, H.; Lähteenmäki, Anne; Lindholm, Valtteri; Poutanen, T.; Suur-Uski, A. -S.; Tuovinen, Jari; Väliviita, Jussi; Planck Collaboration (2014)
  • Hakonen, Maria; May, Patrick J. C.; Jaaskelainen, Iiro P.; Jokinen, Emma; Sams, Mikko; Tiitinen, Hannu (2017)
    Introduction: We examined which brain areas are involved in the comprehension of acoustically distorted speech using an experimental paradigm where the same distorted sentence can be perceived at different levels of intelligibility. This change in intelligibility occurs via a single intervening presentation of the intact version of the sentence, and the effect lasts at least on the order of minutes. Since the acoustic structure of the distorted stimulus is kept fixed and only intelligibility is varied, this allows one to study brain activity related to speech comprehension specifically. Methods: In a functional magnetic resonance imaging (fMRI) experiment, a stimulus set contained a block of six distorted sentences. This was followed by the intact counterparts of the sentences, after which the sentences were presented in distorted form again. A total of 18 such sets were presented to 20 human subjects. Results: The blood oxygenation level dependent (BOLD)-responses elicited by the distorted sentences which came after the disambiguating, intact sentences were contrasted with the responses to the sentences presented before disambiguation. This revealed increased activity in the bilateral frontal pole, the dorsal anterior cingulate/paracingulate cortex, and the right frontal operculum. Decreased BOLD responses were observed in the posterior insula, Heschl's gyrus, and the posterior superior temporal sulcus. Conclusions: The brain areas that showed BOLD-enhancement for increased sentence comprehension have been associated with executive functions and with the mapping of incoming sensory information to representations stored in episodic memory. Thus, the comprehension of acoustically distorted speech may be associated with the engagement of memory-related subsystems. Further, activity in the primary auditory cortex was modulated by prior experience, possibly in a predictive coding framework. Our results suggest that memory biases the perception of ambiguous sensory information toward interpretations that have the highest probability to be correct based on previous experience.
  • Jalko, Joonas; Lagerspetz, Eemil; Haukka, Jari; Tarkoma, Sasu; Honkela, Antti; Kaski, Samuel (2021)
    Differential privacy allows quantifying privacy loss resulting from accession of sensitive personal data. Repeated accesses to underlying data incur increasing loss. Releasing data as privacy-preserving synthetic data would avoid this limitation but would leave open the problem of designing what kind of synthetic data. We propose formulating the problem of private data release through probabilistic modeling. This approach transforms the problem of designing the synthetic data into choosing a model for the data, allowing also the inclusion of prior knowledge, which improves the quality of the synthetic data. We demonstrate empirically, in an epidemiological study, that statistical discoveries can be reliably reproduced from the synthetic data. We expect the method to have broad use in creating high-quality anonymized data twins of key datasets for research.