Kinetic analysis of gan-movpe via thickness profiles in the gas flow direction with systematically varied growth conditions

We carried out a kinetic analysis of metallorganic vapor phase epitaxy (MOVPE) of GaN to investigate the dependence of the growth rate on the process conditions as a function of residence time of the precursors in the reactor. The wafer was not rotated during growth, allowing us to analyze the thickness profile of the film in the direction of gas flow, and hence the dependence of the growth rate on the residence time. The growth rate is determined mainly by the concentration of the growth species and mass transfer of the growth species to the wafer surface. The growth rate peaked in the flow direction, and the position of this peak could, in most cases, be explained by considering a combination of the linear gas velocity and the time constant for vertical diffusion of trimethylgallium (TMGa) and/or growth species across the NH3 feed stream to the wafer surface. In some cases this was not possible, indicating that more complex effects were significant. This work is expected to contribute to understanDing of the reaction pathways for GaN-MOVPE, and the growth rate data reported here are expected to provide useful benchmarks for growth simulations that combine computational fluid dynamics and reaction models

A computational framework for testing hypotheses of the minimal mechanical requirements for cell aggregation using early annual killifish embryogenesis as a model

Introduction: Deciphering the biological and physical requirements for the outset of multicellularity is limited to few experimental models. The early embryonic development of annual killifish represents an almost unique opportunity to investigate de novo cellular aggregation in a vertebrate model. As an adaptation to seasonal drought, annual killifish employs a unique developmental pattern in which embryogenesis occurs only after undifferentiated embryonic cells have completed epiboly and dispersed in low density on the egg surface. Therefore, the first stage of embryogenesis requires the congregation of embryonic cells at one pole of the egg to form a single aggregate that later gives rise to the embryo proper. This unique process presents an opportunity to dissect the self-organizing principles involved in early organization of embryonic stem cells. Indeed, the physical and biological processes required to form the aggregate of embryonic cells are currently unknown. Methods: Here, we developed an in silico, agent-based biophysical model that allows testing how cell-specific and environmental properties could determine the aggregation dynamics of early Killifish embryogenesis. In a forward engineering approach, we then proceeded to test two hypotheses for cell aggregation (cell-autonomous and a simple taxis model) as a proof of concept of modeling feasibility. In a first approach (cell autonomous system), we considered how intrinsic biophysical properties of the cells such as motility, polarity, density, and the interplay between cell adhesion and contact inhibition of locomotion drive cell aggregation into self-organized clusters. Second, we included guidance of cell migration through a simple taxis mechanism to resemble the activity of an organizing center found in several developmental models. Results: Our numerical simulations showed that random migration combined with low cell-cell adhesion is sufficient to maintain cells in dispersion and that aggregation can indeed arise spontaneously under a limited set of conditions, but, without environmental guidance, the dynamics and resulting structures do not recapitulate in vivo observations. Discussion: Thus, an environmental guidance cue seems to be required for correct execution of early aggregation in early killifish development. However, the nature of this cue (e.g., chemical or mechanical) can only be determined experimentally. Our model provides a predictive tool that could be used to better characterize the process and, importantly, to design informed experimental strategies

Ad interim recommendations for the Higgs boson production cross sections at s=13.6\sqrt{s} = 13.6 TeV

This note documents predictions for the inclusive production cross sections of the Standard Model Higgs boson at the Large Hadron Collider at a centre of mass energy of 13.6 TeV. The predictions here are based on simple extrapolations of previously documented predictions published in the CERN Yellow Report "Deciphering the Nature of the Higgs Sector". The predictions documented in this note should serve as a reference while a more complete and update-to-date derivation of cross section predictions is in progress.Comment: 13 pages, 9 tables. Official report of the LHC Higgs Working Grou

A computational framework for testing hypotheses of the minimal mechanical requirements for cell aggregation using early annual killifish embryogenesis as a model

Introduction: Deciphering the biological and physical requirements for the outset of multicellularity is limited to few experimental models. The early embryonic development of annual killifish represents an almost unique opportunity to investigate de novo cellular aggregation in a vertebrate model. As an adaptation to seasonal drought, annual killifish employs a unique developmental pattern in which embryogenesis occurs only after undifferentiated embryonic cells have completed epiboly and dispersed in low density on the egg surface. Therefore, the first stage of embryogenesis requires the congregation of embryonic cells at one pole of the egg to form a single aggregate that later gives rise to the embryo proper. This unique process presents an opportunity to dissect the self-organizing principles involved in early organization of embryonic stem cells. Indeed, the physical and biological processes required to form the aggregate of embryonic cells are currently unknown.Methods: Here, we developed an in silico, agent-based biophysical model that allows testing how cell-specific and environmental properties could determine the aggregation dynamics of early Killifish embryogenesis. In a forward engineering approach, we then proceeded to test two hypotheses for cell aggregation (cell-autonomous and a simple taxis model) as a proof of concept of modeling feasibility. In a first approach (cell autonomous system), we considered how intrinsic biophysical properties of the cells such as motility, polarity, density, and the interplay between cell adhesion and contact inhibition of locomotion drive cell aggregation into self-organized clusters. Second, we included guidance of cell migration through a simple taxis mechanism to resemble the activity of an organizing center found in several developmental models.Results: Our numerical simulations showed that random migration combined with low cell-cell adhesion is sufficient to maintain cells in dispersion and that aggregation can indeed arise spontaneously under a limited set of conditions, but, without environmental guidance, the dynamics and resulting structures do not recapitulate in vivo observations.Discussion: Thus, an environmental guidance cue seems to be required for correct execution of early aggregation in early killifish development. However, the nature of this cue (e.g., chemical or mechanical) can only be determined experimentally. Our model provides a predictive tool that could be used to better characterize the process and, importantly, to design informed experimental strategies

The Lay Preacher

The volume aims to investigate Tony Blair’s political figure, seeking to identify the elements of continuity and disruption between the blairian politics, the Labour Party’s culture and history and Margaret Thatcher’s political legacy. Several aspects of the British Prime Minister are examined: his biography, his rise in the party, his political ideas, his communicative style, and the choices he made once in power, both in domestic and foreign policy, especially in his relationship with the United States and the European Union. In particular, the volume focuses on the first six years of New Labour governments: from the landslide victory in 1997 to the declaration of war on Iraq in 2003, a decisive turning point in Blair’s career and legacy

The Lay Preacher

Il volume si propone di indagare la figura politica di Tony Blair, cercando di individuare gli elementi di continuit\ue0 e di rottura tra la politica blairiana, la cultura e la storia del Labour Party e l’eredit\ue0 politica di Margaret Thatcher. Sono presi in esame diversi aspetti del premier britannico: la biografia, l’ascesa nel partito, le idee politiche, lo stile comunicativo e le scelte compiute una volta al potere, sia in politica interna sia in politica estera, soprattutto nel rapporto con gli Stati Uniti e l’Unione Europea. In particolare, il volume si concentra sui primi sei anni dei Governi New Labour: dalla landslide victory del 1997 alla dichiarazione di guerra all’Iraq nel 2003, spartiacque decisivo nella carriera e nella legacy di Blair

Sustainable scaling in social enterprises serving the Bottom of the Pyramid. St. Mary's Lacor Hospital case study

LAUREA MAGISTRALELa ricerca studia la scalabilità delle imprese sociali che operano in contesti vulnerabili. L'obiettivo primario di questa ricerca è illustrare come le organizzazioni ibride, nello specifico le imprese sociali, possano espandersi attraverso partnership strategiche in contesti Bottom of the Pyramid (BoP), garantendo al contempo la sostenibilità del loro modello di business. La ricerca analizza un caso di studio, il St. Mary Lacor Hospital, situato nella regione rurale dell'Uganda, che fornisce una buona rappresentazione delle imprese sociali che servono le comunità della BoP. In questo contesto specifico, lo studio si concentrerà sull'analisi di due partnership chiave: Able+ e Women for Women. Utilizzando un approccio qualitativo, la ricerca si avvale di diverse fonti, tra cui interviste semi-strutturate, visite in loco e analisi di documenti. I risultati rivelano in primo luogo un impatto sociale estremamente positivo, a beneficio sia della comunità che delle organizzazioni coinvolte. In secondo luogo, evidenziano i vantaggi della scalabilità a livello di ecosistema, sottolineando l’importante presenza di organizzazioni specializzate in attività complementari. Rivolgendosi in particolare alle comunità BoP con risorse limitate e popolazioni vulnerabili, la ricerca sottolinea la necessità dello scambio di risorse e competenze tra gli stakeholder. La tesi si conclude delineando i benefici della scalabilità ottenuta attraverso le partnership strategiche del caso di studio e generalizzando le strategie implementate a beneficio di altre organizzazioni che affrontano sfide simili e aspirano a migliorare il loro impatto sociale. Questa ricerca contribuisce in modo significativo ad ampliare la comprensione delle complessità delle organizzazioni ibride e di come possano sfruttare le loro risorse interne in una collaborazione con un ecosistema di partner con il fine di raggiungere obiettivi comuni.The dissertation investigates the scalability of social enterprises operating in vulnerable contexts. The primary aim of this research is to illustrate how hybrid organizations, specifically social enterprises, can achieve expansion through strategic partnerships in Bottom of the Pyramid (BoP) contexts while ensuring the sustainability of their Hybrid Organization Business Model. The research analyzes the case study, St. Mary’s Lacor Hospital, situated in the rural region of Uganda, which provide a good representation of social enterprises serving the BoP segment of the population. In this specific framework, the study will focus on the analysis of two key partnerships: Able+ and Women for Women. Employing a qualitative approach, the research mobilizes a variety of sources, including semi-structured interviews, site visits, and document analysis. The findings reveal firstly a highly positive social impact outcomes, benefiting both the community and the organizations involved. Secondly, they highlight the advantages of scaling at the ecosystem level, emphasizing the involvement of entities undertaking complementary activities. Specifically targeting BoP communities with limited resources and vulnerable populations, the research underscores the importance of resource and competence exchange among stakeholders. The dissertation concludes by outlining the benefits of scaling achieved through strategic partnerships, drawing insights from the detailed case study and aiming to generalize them for the benefit of other organizations facing similar challenges and aspiring to enhance their social impact. This research significantly contributes to expanding our understanding of the intricacies of hybrid organizations and how leveraging their resources through collaboration within an ecosystem of partners can lead to the attainment of shared goals