Statistics of optimal information flow in ensembles of regulatory motifs

Genetic regulatory circuits universally cope with different sources of noise that limit their ability to coordinate input and output signals. In many cases, optimal regulatory performance can be thought to correspond to configurations of variables and parameters that maximize the mutual information between inputs and outputs. Such optima have been well characterized in several biologically relevant cases over the past decade. Here we use methods of statistical field theory to calculate the statistics of the maximal mutual information (the `capacity') achievable by tuning the input variable only in an ensemble of regulatory motifs, such that a single controller regulates N targets. Assuming (i) sufficiently large N, (ii) quenched random kinetic parameters, and (iii) small noise affecting the input-output channels, we can accurately reproduce numerical simulations both for the mean capacity and for the whole distribution. Our results provide insight into the inherent variability in effectiveness occurring in regulatory systems with heterogeneous kinetic parameters.Comment: 14 pages, 6 figure

A rare cause of left upper quadrant abdominal pain

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Il Congresso statunitense di fronte all’emergenza pandemica. Il dibattito sul remote voting e la questione della costituzionalità del proxy voting introdotto alla Camera tra polarizzazione partitica e deferenza delle Corti (McCarthy v. Pelosi)

L’autore esamina l’impatto dell’emergenza sanitaria causata dalla pandemia da SARS-Cov-2 sul funzionamento del Congresso degli Stati Uniti. Dopo aver ricostruito il dibattito dottrinale innescato da alcune iniziali proposte di modifica dei regolamenti delle due Camere volte a introdurre sistemi di voto da remoto, il saggio focalizza la propria attenzione sul sistema voto per delega adottato dalla Camera dei Rappresentanti al fine di assicurare la continuità dei suoi lavori minimizzando al contempo i rischi per la salute dei suoi membri e del suo personale. In particolare, esso intende evidenziare come il tentativo dei repubblicani di politicizzare tale sistema intentando una causa per contestarne la costituzionalità si sia finora scontrato con la tendenza delle Corti federali a mostrarsi deferenti nei confronti dell’autonomia regolamentare delle Camere.The author examines the impact of the public health emergency due to SARS-Cov-2 pandemic on the functioning of the United States Congress. After analysing the debate on early proposals to amend both Houses’ rules to establish remote voting systems, the essay focuses on the proxy voting system adopted by the House of Representatives in order to ensure its continued operation while protecting the health of members and staff. Notably, it highlights how the Republican attempt to heavily politicise this system by filing a lawsuit that questions its constitutionality has so far collided with federal Courts’ tendency to defer to the authority of each Chamber to determine the rules of its own proceedings

Il treaty-making power nell’era post-Brexit. Quale ruolo per il Parlamento di Westminster?

The treaty-making power in the post-Brexit era. Which is Westminster Parliament’s role? – The essay examines the origins, the evolution, the actual functioning and the future perspectives of the United Kingdom’s system for Parliament’s scrutiny of treaties and other international agreements. Firstly, it focuses on both the foundations of Government’s treaty-making under the royal prerogative and the development of Parliament’s scrutiny from the absolutism to the establishment of the so-called “Ponsonby Rule”. Secondly, it analyses the features and the shortcomings of the two distinct roles Parliament has under the current system for its engagement with treaty-making process: on the one hand, the scrutiny of treaties laid pursuant to Part 2 of Constitutional Reform and Governance Act 2010; on the other hand, the scrutiny of any legislation necessary for the implementation of international obligations in the domestic law. Finally, the inquiry underlines and evaluates the attempts to improve these procedures in the post-Brexit era, as the patriation of the power to make free trade agreements with significant impacts on people’s lives is rising serious concerns over the little accountability and scrutiny of governmental treaty-making power

Il "vortice" dei rapporti centro-periferia tra conflitto e cooperazione. Lo scontro sulla notwithstanding clause e l'intesa sull'assistenza sanitaria

Nel periodo compreso tra gennaio e aprile 2023, a imprimere un forte segno sulle vicende politico-istituzionali canadesi è stata soprattutto la peculiare dinamica dei rapporti tra il livello federale e le entità decentrate – di regola raffigurabile come un “vortice” continuamente alimentato dal moto simultaneo di correnti centrifughe

Adult-type rhabdomyoma of the larynx: clinicopathologic study of an uncommon tumor in a rare location

Rhabdomyoma is an uncommon benign mesenchymal tumor with skeletal muscle differentiation that may occur either in the heart or in extra-cardiac sites. Even though the head and neck region is the most common area of extra-cardiac rhabdomyoma, the larynx is rarely involved. We present the case of an 85-year-old woman who reported a 10-day history of breathing difficulties, dysphagia and dysphonia. A computed tomography scan of the head and neck showed a contrast-enhanced, solid hypopharyngeal-laryngeal neoplasm with well-defined margins causing subtotal obliteration of the right pyriform sinus and a reduction in air lumen of the laryngeal vestibule. The patient underwent complete endoscopic removal of the lesion; histologic examination revealed an adult- type rhabdomyoma based on the histologic features and the immunoreactivity of the neoplastic cells for desmin, myoglobin and muscle-specific actin but not for cytokeratin, S-100, CD68R, chromogranin-A and synaptophysin. Since clinical and imaging features are not specific for rhabdomyoma, histologic examination and immunohistochemical analyses play a central role in the differential diagnosis of the adult-type rhabdomyoma from other laryngeal neoplasms. A correct diagnosis is mandatory to avoid inappropriate treatment

La morte della Regina riapre il dibattito sulla monarchia, mentre si riaccendono tensioni nei rapporti centro-periferia e il Québec è travolto dallo “Tsunami Caquiste"

In Canada, il quadrimestre settembre-dicembre 2022 è stato segnato dal riaccendersi di tensioni nei rapporti tra la Federazione e alcune Province (Québec, Alberta e Saskatchewan), alimentate dall'instaurazione di precedenti di adozione di emendamenti alla Costituzione unilaterali e di altri atti manifestamente illegittimi, perseguita in modo attivo, consapevole e persino entusiastico dagli organi di indirizzo provinciali, e potenzialmente in grado di aprire una grave crisi costituzionale. Anche il dibattito sul futuro della monarchia, innescato dalla morte della Regina Elisabetta II, è stato condizionato dal cleavage politico-istituzionale che storicamente, in Canada, attraversa il versante dei rapporti tra centro e periferia

Declinazioni innovative della democrazia partecipativa e integrazione dei gruppi deboli. Riflessioni comparate e conclusive

Re-thinking about Innovative Perspectives in Participatory Democracy, and in the Integration of Vulnerable Groups: Comparative and Conclusive Remains ‒ Even if providing a unique meaning to qualify ‘participatory democracy’ is quite difficult, the term is doubtlessly connected to a series of instruments in order to reduce the distance between citizenship and institutions. Particularly, participatory instruments are intended to enlarge the democratic parameter by following two guidelines: the one of the digital participations as integrating vulnerable groups, and the one of the citizens’ assemblies as protecting environment

Lessons Learnt from Operating the First Cubesat Mission Equipped with a Hall Thruster

Only a few electric propulsion solutions on-board small satellites have been operated in space, even if propulsion is nowadays seen as one of the most important subsystems for the future of small satellites. Exotrail demonstrated its Hall Effect Thruster propulsion solution in space at the end of 2020. It was the first Hall thruster ever flown onboard a satellite weighing below 100kg of mass, while also being the only known permanent magnet Hall Thruster demonstrated in space. Operations of small satellites with propulsion is a novel field and the behavior of such thrusters in space still brings new challenges. Exotrail developed its ExoMG™ propulsion system demonstrator between November 2018 and September 2019, when the flight model was delivered to the small satellite manufacturer NanoAvionics. The satellite was eventually launched in November 2020 and following the commissioning of the platform, the thruster was conditioned and subsequently fired. These two last steps will be detailed. The propulsion system consists of the propellant storage and regulation system, the control and power electronics, the actual thruster consisting of an anode and a cathode and a mechanical and thermal interface. It is operated through Exotrail’s ExoOPS™ - Operations software. The different subsystems will be described as well as their interaction. Each of them has many observables that will be detailed and discussed –typically temperatures, voltages. The operations software enables the monitoring of the orbital parameters, the maneuver generation, the housekeeping of the propulsion unit and the preparation of the maneuvers. It will be briefly described as it is the main software tool to understand the behavior of the thruster. The commissioning operations of the propulsion unit are firstly focused on health check and controllability of the environmental parameters. Then a health check of the active parts of the propulsion is performed. Finally, the firing sequence is initiated. The different steps, the expected and actual results will be presented and discussed. Finally, we will present the performance estimation of our propulsion unit. Thanks to our on-board GPS data, we perform maneuver restitution and we compare the in-flight performance with ground tests