Search results: Found 10

Listing 1 - 10 of 10
Sort by
Poisson Noise Removal in Spherical Multichannel Images: Application to Fermi Data (Book chapter)

Authors: --- --- ---
ISBN: 9789535102120 Year: DOI: 10.5772/36580 Language: English
Publisher: IntechOpen Grant: FP7 Ideas: European Research Council - 228261
Subject: Science (General)
Added to DOAB on : 2019-01-17 11:47:58
License:

Loading...
Export citation

Choose an application

Abstract

The Fermi Gamma-ray Space Telescope, which was launched by NASA in June 2008, is a powerful space observatory which studies the high-energy gamma-ray sky Atwood (2009). Fermi’s main instrument, the Large Area Telescope (LAT), detects photons in an energy range between 20 MeV to greater than 300 GeV. The LAT is much more sensitive than its predecessor, the EGRET telescope on the Compton Gamma Ray Observatory, and is expected to find several thousand gamma-ray point sources, which is an order of magnitude more than its predecessor EGRET Hartman et al. (1999).

Using Noise to Characterize Vision

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197538 Year: Pages: 127 DOI: 10.3389/978-2-88919-753-8 Language: English
Publisher: Frontiers Media SA
Subject: Psychology --- Science (General)
Added to DOAB on : 2016-04-07 11:22:02
License:

Loading...
Export citation

Choose an application

Abstract

Noise has been widely used to investigate the processing properties of various visual functions (e.g. detection, discrimination, attention, perceptual learning, averaging, crowding, face recognition), in various populations (e.g. older adults, amblyopes, migrainers, dyslexic children), using noise along various dimensions (e.g. pixel noise, orientation jitter, contrast jitter). The reason to use external noise is generally not to characterize visual processing in external noise per se, but rather to reveal how vision works in ordinary conditions when performance is limited by our intrinsic noise rather than externally added noise. For instance, reverse correlation aims at identifying the relevant information to perform a given task in noiseless conditions and measuring contrast thresholds in various noise levels can be used to understand the impact of intrinsic noise that limits sensitivity to noiseless stimuli. Why use noise? Since Fechner named it, psychophysics has always emphasized the systematic investigation of conditions that break vision. External noise raises threshold hugely and selectively. In hearing, Fletcher used noise in his famous critical-band experiments to reveal frequency-selective channels in hearing. Critical bands have been found in vision too. More generally, the big reliable effects of noise give important clues to how the system works. And simple models have been proposed to account for the effects of visual noise. As noise has been more widely used, questions have been raised about the simplifying assumptions that link the processing properties in noiseless conditions to measurements in external noise. For instance, it is usually assumed that the processing strategy (or mechanism) used to perform a task and its processing properties (e.g. filter tuning) are unaffected by the addition of external noise. Some have suggested that the processing properties could change with the addition of external noise (e.g. change in filter tuning or more lateral masking in noise), which would need to be considered before drawing conclusions about the processing properties in noiseless condition. Others have suggested that different processing properties (or mechanisms) could be solicited in low and high noise conditions, complicating the characterization of processing properties in noiseless condition based on processing properties identified in noise conditions. The current Research Topic probes further into what the effects of visual noise tell us about vision in ordinary conditions. Our Editorial gives an overview of the articles in this special issue.

Soundings

Authors: ---
ISBN: 9781862181540 Year: Pages: 303 DOI: 10.26530/OAPEN_1003986 Language: English
Publisher: University of Huddersfield Press
Subject: Arts in general
Added to DOAB on : 2019-01-17 11:41:37
License:

Loading...
Export citation

Choose an application

Abstract

This book draws on the lived experience of sound’s capacity to move and shake us in direct, subtle and profound ways through speech, location sound, and music in documentary film. The associative, connotative and sheer emotive power of sound has the capacity to move and shake us in a myriad of direct, subtle and often profound ways. The implications of this for its role as speech, location sound, and music in documentary film are far-reaching. The writers in this book draw on the lived experience of sound’s resounding capacity as primary motivation for exploring these implications, united by the overarching theme of how listening is connected with acts of making sense both on its own terms and in conjunction with viewing. The resulting thirteen essays of Soundings: Documentary Film and the Listening Experience cover films made from WWII to the present day in locations across Europe and the Americas, and in styles ranging from political propaganda, industrial promotion and educative exposition, to more aesthetically-driven films taking their bearings from avant-garde art. The authors draw on their experience in scholarly research, practice-as-research, and in the aesthetic and technical practice of documentary filmmaking. This mix of perspectives aims to widen and deepen the outlook of the recent and growing academic interest in the topic of documentary film sound.

Keywords

Sound --- noise --- music --- speech --- soundings

Acoustical Impact of Ships and Harbours: Airborne and Underwater N&V Pollution

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889457106 Year: Pages: 57 DOI: 10.3389/978-2-88945-710-6 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Oceanography
Added to DOAB on : 2019-01-23 14:53:43
License:

Loading...
Export citation

Choose an application

Abstract

Noise and vibrations generated by ships affect a wide range of receivers: crew and passengers inside the vessel, inhabitants of the coastal areas and marine fauna outside it. Recent studies suggest that a large percentage of people living in urban areas close to harbors and a number of marine species, at different evolutionary levels (in particular mammals and cephalopods), suffer from ship N&V emissions in air and in water. The present degree of knowledge of the phenomena involved in the noise emissions inside and outside ships is quite different, as a result also of the time elapsed since the negative effects were realized and therefore studied. The development of the normative framework in the various areas reflects these differences, but there are expectations for improvements on all fronts that need to be supported by the scientific community presenting the latest research results in this particular field of acoustics.

Investigating the human brainstem with structural and functional MRI

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192472 Year: Pages: 92 DOI: 10.3389/978-2-88919-247-2 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2015-11-16 15:44:59
License:

Loading...
Export citation

Choose an application

Abstract

The brainstem is one of the least understood parts of the human brain despite its prime importance for the maintenance of basic vital functions. Owing to its role as a relay station between spinal cord, cerebellum and neocortex, the brainstem contains vital nodes of all functional systems in the central nervous system, including the visual, auditory, gustatory, vestibular, somatic and visceral senses, and the somatomotor as well as autonomic nervous systems. While the brainstem has been extensively studied in animals using invasive methods, human studies remain scarce. Magnetic resonance imaging (MRI) as a non-invasive and widely available method is one possibility to access the brainstem in humans and measure its structure as well as function. The close vicinity of the brainstem to large arteries and ventricles and the small size of the anatomical structures, however, place high demands on imaging as well as data analysis methods. Nevertheless, the field of brainstem-(f)MRI has significantly advanced in the past few years, largely due to the development of several new tools that facilitate studying this critical part of the human brain. Within this scope, the goal of this Research Topic is to compile work representing the state of the art in functional and structural MRI of the human brainstem.

Neuronal Stochastic Variability: Influences on Spiking Dynamics and Network Activity

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198849 Year: Pages: 156 DOI: 10.3389/978-2-88919-884-9 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2016-01-19 14:05:46
License:

Loading...
Export citation

Choose an application

Abstract

Stochastic fluctuations are intrinsic to and unavoidable at every stage of neural dynamics. For example, ion channels undergo random conformational changes, neurotransmitter release at synapses is discrete and probabilistic, and neural networks are embedded in spontaneous background activity. The mathematical and computational tool sets contributing to our understanding of stochastic neural dynamics have expanded rapidly in recent years. New theories have emerged detailing the dynamics and computational power of the balanced state in recurrent networks. At the cellular level, novel stochastic extensions to the classical Hodgkin-Huxley model have enlarged our understanding of neuronal dynamics and action potential initiation. Analytical methods have been developed that allow for the calculation of the firing statistics of simplified phenomenological integrate-and-fire models, taking into account adaptation currents or temporal correlations of the noise. This Research Topic is focused on identified physiological/internal noise sources and mechanisms. By "internal", we mean variability that is generated by intrinsic biophysical processes. This includes noise at a range of scales, from ion channels to synapses to neurons to networks. The contributions in this Research Topic introduce innovative mathematical analysis and/or computational methods that relate to empirical measures of neural activity and illuminate the functional role of intrinsic noise in the brain.

Correlated neuronal activity and its relationship to coding, dynamics and network architecture

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193578 Year: Pages: 236 DOI: 10.3389/978-2-88919-357-8 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2016-03-10 08:14:32
License:

Loading...
Export citation

Choose an application

Abstract

Correlated activity in populations of neurons has been observed in many brain regions and plays a central role in cortical coding, attention, and network dynamics. Accurately quantifying neuronal correlations presents several difficulties. For example, despite recent advances in multicellular recording techniques, the number of neurons from which spiking activity can be simultaneously recorded remains orders magnitude smaller than the size of local networks. In addition, there is a lack of consensus on the distribution of pairwise spike cross correlations obtained in extracellular multi-unit recordings. These challenges highlight the need for theoretical and computational approaches to understand how correlations emerge and to decipher their functional role in the brain.

Metastable Dynamics of Neural Ensembles

Authors: --- --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454372 Year: Pages: 152 DOI: 10.3389/978-2-88945-437-2 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2018-11-16 17:17:57
License:

Loading...
Export citation

Choose an application

Abstract

A classical view of neural computation is that it can be characterized in terms of convergence to attractor states or sequential transitions among states in a noisy background. After over three decades, is this still a valid model of how brain dynamics implements cognition? This book provides a comprehensive collection of recent theoretical and experimental contributions addressing the question of stable versus transient neural population dynamics from complementary angles. These studies showcase recent efforts for designing a framework that encompasses the multiple facets of metastability in neural responses, one of the most exciting topics currently in systems and computational neuroscience.

Aging, neurogenesis and neuroinflammation in hearing loss and protection

Authors: --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196449 Year: Pages: 151 DOI: 10.3389/978-2-88919-644-9 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Neurology
Added to DOAB on : 2016-08-16 10:34:25
License:

Loading...
Export citation

Choose an application

Abstract

Worldwide, 278 million people are estimated to have moderate to profound hearing loss. Age-related hearing loss, also known as presbyacusis, affects approximately half of the population over 60 years old, making it the second most common cause of disability in older people. Hearing loss occurs when the sensory cells and neurons of the cochlea degenerate and die. The vestibular system, which holds the sense of balance, shares a common embryonic origin with the cochlea and together conform the inner ear. Balance problems are a trait of ageing to the point that balance ability is considered a sensor of physical decline and vestibular degeneration is the most common cause of falls in the elderly. Still the molecular bases of ageing in the vestibular system have not been studied in detail. Genetic and environmental factors contribute to the progression of age-related hearing loss (ARHL). Being noise the main environmental noxious agent for human hearing in the industrialized societies. There is no restorative treatment for deafness but functional replacement by means of prosthesis. Therefore, prevention and treatment of hearing loss is an unmet medical need. To develop innovative medical strategies against hearing loss, it is critical to understand the causes of ARHL and the essential pathways responsible for the manifestation of this complex disease. In this research topic, experts will discuss the stages and molecular elements of the damage and repair processes involved in ARHL, from cellular processes to molecules involved in aging. Oxidative stress takes a central stage as an essential element in the progression of injury and cell loss, and a target for cell protection strategies. Finally, the mechanisms of action and the potential of novel therapies for hair cell repair and protection will be discussed along with drug delivery strategies.

Manipulative approaches to human brain dynamics

Authors: --- --- ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194797 Year: Pages: 246 DOI: 10.3389/978-2-88919-479-7 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2016-03-10 08:14:33
License:

Loading...
Export citation

Choose an application

Abstract

In this EBook, we highlight how newly emerging techniques for non-invasive manipulation of the human brain, combined with simultaneous recordings of neural activity, contribute to the understanding of brain functions and neural dynamics in humans. A growing body of evidence indicates that the neural dynamics (e.g., oscillations, synchrony) are important in mediating information processing and networking for various functions in the human brain. Most of previous studies on human brain dynamics, however, show correlative relationships between brain functions and patterns of neural dynamics measured by imaging methods such as electroencephalography (EEG), magnetoencephalography (MEG), near-infrared spectroscopy (NIRS), positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). In contrast, manipulative approaches by non-invasive brain stimulation (NIBS) have been developed and extensively used. These approaches include transcranial magnetic stimulation (TMS) and transcranial electric stimulation (tES) such as transcranial direct current stimulation (tDCS), alternating current stimulation (tACS), and random noise stimulation (tRNS), which can directly manipulate neural dynamics in the intact human brain. Although the neural-correlate approach is a strong tool, we think that manipulative approaches have far greater potential to show causal roles of neural dynamics in human brain functions. There have been technical challenges with using manipulative methods together with imaging methods. However, thanks to recent technical developments, it has become possible to use combined methods such as TMS–EEG coregistration. We can now directly measure and manipulate neural dynamics and analyze functional consequences to show causal roles of neural dynamics in various brain functions. Moreover, these combined methods can probe brain excitability, plasticity and cortical networking associated with information processing in the intact human brain. The contributors to this EBook have succeeded in showcasing cutting-edge studies and demonstrate the huge impact of their approaches on many areas in human neuroscience and clinical applications.

Listing 1 - 10 of 10
Sort by
Narrow your search

Publisher

Frontiers Media SA (8)

IntechOpen (1)

University of Huddersfield Press (1)


License

CC by (10)


Language

english (10)


Year
From To Submit

2019 (1)

2018 (2)

2016 (2)

2015 (2)

2014 (2)

2012 (1)