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The aim of this paper is to provide the theoretical conceptualization of a bandpass (BP) negative group delay (NGD) microstrip circuit. The main objective is to provide a theorization of the particular geometry of the microstrip circuit with experimental validation of the NGD effect.

The methodology followed in this work is organized in three steps. A theoretical model is established of equivalent S-parameters model using Y-matrix analysis. The GD analysis is also presented by showing that the circuit presents a possibility to generate NGD function around certain frequencies. To validate the theoretical model, as proof-of-concept (POC), a microstrip prototype is designed, fabricated and tested.

This work clearly highlighted the modelled (analytical design model), simulated (ADS simulation tool) and measured results are in good correlation. Relying on the proposed theoretical, numerical and experimental models, the BP NGD behaviour is validated successfully with GD responses specified by the NGD centre frequency: it is observed around 2.35 GHz, with an NGD value of about −2 ns.

It is to be noticed the proposed GD analysis requires limitations of the theoretical NGD model. It is depicted and validated through a POC demonstrating that the circuit presents a possibility to generate NGD function around certain frequencies (assuming constraints around usable frequency and bandwidth).

The NGD O-shape topology developed in this work could be exploited in the future in the microwave and radiofrequency context. Thus, it is expected to develop GD equalization technique for radiofrequency and microwave filters, GD compensation of oscillators, filters and communication systems, design of broadband switch-less bi-directional amplifiers, efficient enhancement of feedforward amplifiers, design method of frequency independent phase shifters with negligible delay, synthesis method of arbitrary-angle beamforming antennas. The BP NGD behavior may also be successfully used for the reduction of resonance effect for the electronic compatibility (EMC) of electronic devices.

The non-conventional NGD O-circuit theoretical development and validation through experimental POC could be exploited by academic and industrial developers in the area of wireless communications including, but not restricted to, 5-generation communication systems. The use of the remarkable NGD effect is also useful for the mitigation of electromagnetic interferences between electronic devices and more and more complex electromagnetic environment (current development of Internet of Things[ IoT]).

The originality of this work relies on the new NGD design proposed in this work including the extraction of S-matrix parameters of the microstrip novel structure designed. The validation process based upon an experimental POC showed very interesting levels of NGD O-circuit (nanosecond-GD duration).

The purpose of this paper is to analyze the context of the emergence of a skin infection outbreak in the aftermath of Hurricane Matthew in Haiti and detail the role of community-based participatory research in mobilizing local action in a country with low state capacity.

While implementing a post-disaster study that combined a survey of 984 households and 69 community leaders with 23 focus groups, 60 ethnographic interviews and community mapping, a skin infection outbreak was detected. Using study results, the research team in partnership with different stakeholders responded to the outbreak with a health intervention.

The findings illustrate how pre-existing conditions shape local communities' vulnerability to health crises in the aftermath of disasters and the critical role research can play in informing the recovery processes. Community-based approaches to emergency health reinforced by multi-stakeholder partnerships with local government can strengthen post-disaster response and governance structures setting the groundwork for the development of local resilience.

The health intervention was implemented as a result of the study. Patients served were not derived from the study sample but were self-selected based on their need for skin-related medical treatment.

This article highlights the integral role research can play in identifying the health impacts of disaster events in vulnerable, hard-to-reach communities and strengthening government involvement in disaster governance.