Compensated Current Injection circuit, theory and applications

This paper presents a detailed description, analysis and example of practical application of a wide frequency band voltage-to-current converter. The converter is characterized by a combination of positive and negative feedback loops. This feature allows compensation for parasitic impedance connected in parallel with the useful load, which in turn keeps an excitation current flowing through the useful load independent of its impedance. The simplicity of the circuit and its good electrical properties are additional advantages of the scheme.Comment: 9 pages and 7 figures in one PDF fil

A system for rapid measurement and direct customization of head related impulse responses

Head-Related Impulse Responses (HRIRs) measurement systems are quite complex and present long acquisition times for an accurate sampling of the full 3D space. Therefore HRIRs customization has become an important research topic. In HRIRs customization some parameters (generally anthropometric measurements) are obtained from new listeners and ad-hoc HRIRs can be retrieved from them. Another way to get new listeners parameters is to measure a subset of the full 3D space HRIRs and extrapolate them in order to obtain a full 3D database. This partial acquisition system, of course, should be rapid and accurate. In this paper we present a system which allows for rapid acquisition and equalization of HRIRs for a subset of the 3D grid. Then a technique to carry out HRIR customization based on the measured HRIRs will be described

Returning to Center: Two Views of the Centro Internacional of Bogota (1959–1982)

In the present–day city, both the architecture and the quality of its urban spaces are key issues for defining urban strategies that are aimed at improving the livability in the city, in its new metropolitan state. Given the inevitability of the changes that the city itself demonstrates, implicitly and explicitly, a return to the center, to the places with relationships between men and things and with humanized space, offers a possible solution. In this light, the Tequendama–Bavaria complex (1950–1982) within the International Center of Bogota is a center that reveals a series of urban values that may be used as reference points in the challenge of building a polycentric city and in the configuration of livable urban spaces. By analyzing different views since the origins of the city, we can appreciate the consolidation of a project based on the values of territorial and urban “mediation”, which are able to assemble rather than disperse, to integrate rather than segregate, invite rather than repel, and open up rather than close in

A Conceptual Model on the Relationships Between Business Strategy, Business Model Innovation, Resource Configuration and Performance

The main objective of this study is to develop a research framework for strategic management researchers to develop sound strategic business model innovation that has practical implication on how to innovate firms\u27 business models. The research identifies factors attributing to effective business model: business strategies, type of business model innovations and types of resource configurations. This study framework can guide leaders and managers to acquire the appropriate capability of coping with business model dynamics as well as major transformation that arises from business model innovations. In addition, the study provides insightful contributions in explaining the influence of business strategies (defender, prospector, analyzer) on business model innovations and firm resource configuration, and their influence on business model effectiveness. This study model is valuable considering the limited amount of empirical work previously done on the topic in question. Based on a case-study research survey in seven companies in Indonesia that took place in 2011-2012, we have drawn first conclusions expressed in four research propositions that deem further tests. One case (Food Co.) is highlighted for the description of the study to show some presence and absence of alignment between business strategy, business model innovation, and resource configuration

Cardiac Amyloidosis: A Review of Current Imaging Techniques

Systemic amyloidosis is a rare, heterogenous group of diseases characterized by extracellular infiltration and deposition of amyloid fibrils. Cardiac amyloidosis (CA) occurs when these fibrils deposit within the myocardium. Untreated, this inevitably leads to progressive heart failure and fatality. Historically, treatment has remained supportive, however, there are now targeted disease-modifying therapeutics available to patients with CA. Advances in echocardiography, cardiac magnetic resonance (CMR) and repurposed bone scintigraphy have led to a surge in diagnoses of CA and diagnosis at an earlier stage of the disease natural history. CMR has inherent advantages in tissue characterization which has allowed us to better understand the pathological disease process behind CA. Combined with specialist assessment and repurposed bone scintigraphy, diagnosis of CA can be made without the need for invasive histology in a significant proportion of patients. With existing targeted therapeutics, and novel agents being developed, understanding these imaging modalities is crucial to achieving early diagnosis for patients with CA. This will allow for early treatment intervention, accurate monitoring of disease course over time, and thereby improve the length and quality of life of patients with a disease that historically had an extremely poor prognosis. In this review, we discuss key radiological features of CA, focusing on the two most common types; immunoglobulin light chain (AL) and transthyretin (ATTR) CA. We highlight recent advances in imaging techniques particularly in respect of their clinical application and utility in diagnosis of CA as well as for tracking disease change over time

Quantum dot opto-mechanics in a fully self-assembled nanowire

We show that fully self-assembled optically-active quantum dots (QDs) embedded in MBE-grown GaAs/AlGaAs core-shell nanowires (NWs) are coupled to the NW mechanical motion. Oscillations of the NW modulate the QD emission energy in a broad range exceeding 14 meV. Furthermore, this opto-mechanical interaction enables the dynamical tuning of two neighboring QDs into resonance, possibly allowing for emitter-emitter coupling. Both the QDs and the coupling mechanism -- material strain -- are intrinsic to the NW structure and do not depend on any functionalization or external field. Such systems open up the prospect of using QDs to probe and control the mechanical state of a NW, or conversely of making a quantum non-demolition readout of a QD state through a position measurement.Comment: 20 pages, 6 figure