Optical Communication

Optical communication is very much useful in telecommunication systems, data processing and networking. It consists of a transmitter that encodes a message into an optical signal, a channel that carries the signal to its desired destination, and a receiver that reproduces the message from the received optical signal. It presents up to date results on communication systems, along with the explanations of their relevance, from leading researchers in this field. The chapters cover general concepts of optical communication, components, systems, networks, signal processing and MIMO systems. In recent years, optical components and other enhanced signal processing functions are also considered in depth for optical communications systems. The researcher has also concentrated on optical devices, networking, signal processing, and MIMO systems and other enhanced functions for optical communication. This book is targeted at research, development and design engineers from the teams in manufacturing industry, academia and telecommunication industries

Constraints on Language Learning : behavioral and neurocognitive studies with adults and children

This thesis will contribute to a body of experimental work addressing the question of whether language learning plays a role in certain fundamental design properties of natural languages. Methodologically, this thesis seeks to extend the artificial language learning paradigm, investigating whether learners are sensitive to the constraints embodied by key properties of languages. For example, we will explore whether communicative pressure influences the final outcome of language learning, namely how the structures that are acquired by individuals are transmitted to downstream generations. We will also explore how basic language learning constraints operate in different age groups and, importantly, cross-linguistically. Next to the behavioral experiments focusing on learning and its outcomes, we will look at preliminary electrophysiological correlates of basic compositional processing in the early stages of learning a miniature artificial language using electroencephalography (EEG). In this general introduction I will briefly discuss some of the relevant concepts and methods which will be used in three studies that constitute this thesis

Definition and design of a new communication protocol and interfaces for data transmission in High Energy Physics experiments

High Energy Physics experiments have very similar architectures with respect to systems for acquisition of data from sensors and for control and management of the detector, and therefore similar requirements about data rate, trigger latency, robustness of critical data against transmission errors, radiation hardness and power dissipation and of hardware components and material budget. The use of common solutions that can be reused in different applicative contexts can reduce costs, risks and time needed for the development of new experiments. In particular, a research and development activity appeared as useful in the field of electrical links that are employed for data transmission to and from Front End circuits inside the detectors to move power-consuming optical converters away from the interaction point. Moving from these considerations, the FF-LYNX (Fast and Flexible links) project was started in January 2009 by a collaboration between INFN-PI (Italian National Institute for Nuclear Physics, division of Pisa) and the Department of Information Engineering (DII_IET) of the University of Pisa, with the aim of defining a new serial communication protocol for integrated distribution of TTC signals and Data Acquisition, satisfying the typical requirements of HEP applications and providing flexibility for its adaptation to different scenarios, and of its implementation in radiation-tolerant, low power interfaces. The work presented in this thesis constituted a phase of the FF-LYNX project working plan and was carried out at the Pisa division of INFN: in particular, it dealt with the definition of a first version of the FF-LYNX protocol and the design of hardware transmitter and receiver interfaces implementing it. In this thesis first of all the purposes of the project are presented and the methodology defined for the project work is outlined; then the FF-LYNX protocol (version 1) is described: the basic issues about trigger and data transmission that were considered in the definition of this version of the protocol are outlined, as well as the solutions that were adopted to address these issues, and the results of simulations in a high-level model of the link, intended to estimate various aspects of the protocol performance, are presented. Subsequently, the architecture that was defined for the interfaces implementing the FF-LYNX protocol version 1 is illustrated, and the VHDL models of the transmitter and receiver blocks that was created in the design phase of the FF-LYNX interfaces is described in detail also reporting results of simulations on a VHDL test bench for the complete transmitter-receiver system. Finally, an FPGA based emulator for the FF-LYNX transmitter-receiver system, foreseen as the final result for the FF-LYNX project first year of activity, is outlined in its functional architecture, the development board chosen for its implementation is briefly described, and the results of preliminary synthesis trials of the designed TX and RX blocks onto the target FPGA are reported

New Platforms for Optical Biosensing

Physicochemical experimental techniques combined with the specificity of a biological recognition system have resulted in a variety of new analytical devices known as biosensors. Biosensors are under intensive development worldwide because they have many potential applications, e.g. in the fields of clinical diagnostics, food analysis, and environmental monitoring. Much effort is spent on the development of highly sensitive sensor platforms to study interactions on the molecular scale. In the first part, this thesis focuses on exploiting the biosensing application of nanoporous gold (NPG) membranes. NPG with randomly distributed nanopores (pore sizes less than 50 nm) will be discussed here. The NPG membrane shows unique plasmonic features, i.e. it supports both propagating and localized surface plasmon resonance modes (p SPR and l-SPR, respectively), both offering sensitive probing of the local refractive index variation on/in NPG. Surface refractive index sensors have an inherent advantage over fluorescence optical biosensors that require a chromophoric group or other luminescence label to transduce the binding event. In the second part, gold/silica composite inverse opals with macroporous structures were investigated with bio- or chemical sensing applications in mind. These samples combined the advantages of a larger available gold surface area with a regular and highly ordered grating structure. The signal of the plasmon was less noisy in these ordered substrate structures compared to the random pore structures of the NPG samples. In the third part of the thesis, surface plasmon resonance (SPR) spectroscopy was applied to probe the protein-protein interaction of the calcium binding protein centrin with the heterotrimeric G-protein transducin on a newly designed sensor platform. SPR spectroscopy was intended to elucidate how the binding of centrin to transducin is regulated towards understanding centrin functions in photoreceptor cells.Physikochemische instrumentelle Techniken, die mit der Spezifität eines biologischen Erkennungssystems kombiniert sind, resultierten in unzähligen neuen analytischen Geräten bekannt als Biosensoren. In die Entwicklung von Biosensoren wird weltweit viel investiert angesichts der zahlreichen potentiellen Anwendungen, wie z.B. in der klinischen Diagnostik, der Nahrungsmittelanalyse und zur Umweltüberwachung. Hochempfindliche Sensor-Plattfor-men werden benötigt, um Wechselwirkungen auf molekularer Ebene zu studieren. Im ersten Teil der Doktorarbeit werden nanoporöse Gold (NPG)-Membranen im bezug auf ihre biosensorische Anwendung untersucht. NPG Proben mit einer willkürlichen Porengrößenverteilung (Poren von weniger als 50 nm) werden hierzu erforscht. Die NPG Membranen zeigen einzigartige plasmonische Eigenschaften, d.h. propagierende und lokalisierte Oberflächenplasmonresonanzmodi (p-SPR bzw. l-SPR) können gleichzeitig angeregt werden. Beide Moden ermöglichen eine sensitive Detektion der lokalen Brechungsindexveränderung an/im nanoporösen Gold Substrat. Der große Vorteil der Brechungsindexsensoren im Vergleich zu fluoreszenz-optischen Biosensoren besteht darin, daß keine chromophore Gruppe oder Lumineszenzmarkierung zur Detektion benötigt wird. Im zweiten Teil der Arbeit wurden macroporöse, aus Gold und Silica zusammengesetzte inverse Opale auf ihre bio- bzw. chemischen Sensorfähigkeiten hin analysiert. Diese Substrate kombinieren den Vorzug einer großen verfügbaren Oberfläche mit einer hoch geordneten Gitterstruktur. Das Plasmonensignal ist bei einer geordneten Substratstruktur weniger verrauscht als es bei der willkürlichen Anordnung der Poren im NPG der Fall ist. Im dritten Teil der Doktorarbeit wird die Oberfächenplasmonenresonanz (SPR) Spektroskopie angewendet, um die Protein-Protein Wechselwirkung zwischen dem Calcium bindenden Protein Centrin und dem heterotrimeren G-Protein Transducin zu erforschen. Dazu wurde eine neue Sensorplattform entwickelt. Die SPR Spektroskopie sollte aufklären, wie die Bindung des Centrins zum Transducin reguliert wird und zum besseren Verständnis der Centrinfunktionen in den Photorezeptorzellen beitragen

Nanofluidics for Static and Dynamic DNA-Protein Interaction Studies - Repair of Double-Strand Breaks from a Single-Molecule Perspective

Double-strand breaks (DSBs) is one of the most lethal forms of DNA damage. A single DSB may result in stalling of vital cellular machineries, and thus, requires immediate measures by the cell. Although the main hallmarks of DSB repair mechanisms are known for most prokaryotes and eukaryotes, details on crucial intermediate steps are still to be explained, such as how the free DNA ends are kept in close proximity during the repair process.\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 In the original work, upon which this Thesis is based, the two main DSB repair mechanisms, homologous recombination (HR) and non-homologous end-joining (NHEJ), have been studied from a molecular perspective. A fluorescence-based single-molecule nanofluidics assay has been developed and employed to characterize and visualize static biomolecular interactions between DNA and key DSB repairing proteins. Furthermore, a novel dynamic nanofluidic device has been developed to enable dynamic interaction studies in real time, allowing analytes to be introduced on-demand to stretched DNA molecules.\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Single-molecule characterization of the NHEJ mechanism in Bacillus subtilis, comprising the Ku and Ligase D proteins, revealed that the end-joining activity is mediated by C-terminal protrusions on the homodimeric Ku complex. Using the novel dynamic nanofluidic device, the Ku homodimer was further demonstrated to stay bound to the DNA ends and junctions after completed repair, similar to the human Ku70/80 heterodimer. In addition, the traditional static nanofluidic device was used to identify a previously unknown potential DNA-bridging role of CtIP, a key protein in the human HR process. This could possibly explain how broken DNA ends are kept in close proximity during the initial steps of DSB repair through HR in humans. A similar method was employed to show that the Xrs2 component is indispensable for the end-joining activity of the Mre11-Rad50-Xrs2 complex of Saccharomyces cerevisiae

An Algorithmic Interpretation of Quantum Probability

The Everett (or relative-state, or many-worlds) interpretation of quantum mechanics has come under fire for inadequately dealing with the Born rule (the formula for calculating quantum probabilities). Numerous attempts have been made to derive this rule from the perspective of observers within the quantum wavefunction. These are not really analytic proofs, but are rather attempts to derive the Born rule as a synthetic a priori necessity, given the nature of human observers (a fact not fully appreciated even by all of those who have attempted such proofs). I show why existing attempts are unsuccessful or only partly successful, and postulate that Solomonoff's algorithmic approach to the interpretation of probability theory could clarify the problems with these approaches. The Sleeping Beauty probability puzzle is used as a springboard from which to deduce an objectivist, yet synthetic a priori framework for quantum probabilities, that properly frames the role of self-location and self-selection (anthropic) principles in probability theory. I call this framework "algorithmic synthetic unity" (or ASU). I offer no new formal proof of the Born rule, largely because I feel that existing proofs (particularly that of Gleason) are already adequate, and as close to being a formal proof as one should expect or want. Gleason's one unjustified assumption--known as noncontextuality--is, I will argue, completely benign when considered within the algorithmic framework that I propose. I will also argue that, to the extent the Born rule can be derived within ASU, there is no reason to suppose that we could not also derive all the other fundamental postulates of quantum theory, as well. There is nothing special here about the Born rule, and I suggest that a completely successful Born rule proof might only be possible once all the other postulates become part of the derivation. As a start towards this end, I show how we can already derive the essential content of the fundamental postulates of quantum mechanics, at least in outline, and especially if we allow some educated and well-motivated guesswork along the way. The result is some steps towards a coherent and consistent algorithmic interpretation of quantum mechanics

Molecular Mechanisms of Sensorineural Hearing Loss and Development of Inner Ear Therapeutics

The sense of hearing is vulnerable to environmental challenges, such as exposure to noise. More than 1.5 billion people experience some decline in hearing ability during their lifetime, of whom at least 430 million will be affected by disabling hearing loss. If not identified and addressed in a timely way, hearing loss can severely reduce the quality of life at various stages. Some causes of hearing loss can be prevented, for example from occupational or leisure noise. The World Health Organization estimates that more than 1 billion young people put themselves at risk of permanent hearing loss by listening to loud music over long periods of time. Mitigating such risks through public health action is essential to reduce the impact of hearing loss in the community. The etiology of sensorineural hearing loss is complex and multifactorial, arising from congenital and acquired causes. This book highlights the diverse range of approaches to sensorineural hearing loss, from designing new animal models of age-related hearing loss, to the use of microRNAs as biomarkers of cochlear injury and drug repurposing for the therapy of age-related and noise-induced hearing loss. Further investigation into the underlying molecular mechanisms of sensorineural hearing loss and the integration of the novel drug, cell, and gene therapy strategies into controlled clinical studies will permit significant advances in a field where there are currently many unmet needs

PRINCIPLES OF INFORMATION PROCESSING IN NEURONAL AVALANCHES

How the brain processes information is poorly understood. It has been suggested that the imbalance of excitation and inhibition (E/I) can significantly affect information processing in the brain. Neuronal avalanches, a type of spontaneous activity recently discovered, have been ubiquitously observed in vitro and in vivo when the cortical network is in the E/I balanced state. In this dissertation, I experimentally demonstrate that several properties regarding information processing in the cortex, i.e. the entropy of spontaneous activity, the information transmission between stimulus and response, the diversity of synchronized states and the discrimination of external stimuli, are optimized when the cortical network is in the E/I balanced state, exhibiting neuronal avalanche dynamics. These experimental studies not only support the hypothesis that the cortex operates in the critical state, but also suggest that criticality is a potential principle of information processing in the cortex. Further, we study the interaction structure in population neuronal dynamics, and discovered a special structure of higher order interactions that are inherent in the neuronal dynamics

Nonlinear Dynamics

This volume covers a diverse collection of topics dealing with some of the fundamental concepts and applications embodied in the study of nonlinear dynamics. Each of the 15 chapters contained in this compendium generally fit into one of five topical areas: physics applications, nonlinear oscillators, electrical and mechanical systems, biological and behavioral applications or random processes. The authors of these chapters have contributed a stimulating cross section of new results, which provide a fertile spectrum of ideas that will inspire both seasoned researches and students