Solid effect DNP polarization dynamics in a system of many spins

We discuss the polarization dynamics during solid effect dynamic nuclear polarization (DNP) in a central spin model that consists of an electron surrounded by many nuclei. To this end we use a recently developed formalism and validate first its performance by comparing its predictions to results obtained by solving the Liouville von Neumann master equation. The use of a Monte Carlo method in our formalism makes it possible to significantly increase the number of spins considered in the model system. We then analyse the dependence of the nuclear bulk polarization on the presence of nuclei in the vicinity of the electron and demonstrate that increasing the minimal distance between nuclei and electrons leads to a rise of the nuclear bulk polarization. These observations have implications for the design of radicals that can lead to improved values of nuclear spin polarization. Furthermore, we discuss the potential to extend our formalism to more complex spin systems such as cross effect DNP

Many-body kinetics of dynamic nuclear polarization by the cross effect

Dynamic nuclear polarization (DNP) is an out-of-equilibrium method for generating nonthermal spin polarization which provides large signal enhancements in modern diagnostic methods based on nuclear magnetic resonance. A particular instance is cross-effect DNP, which involves the interaction of two coupled electrons with the nuclear spin ensemble. Here we develop a theory for this important DNP mechanism and show that the nonequilibrium nuclear polarization buildup is effectively driven by three-body incoherent Markovian dissipative processes involving simultaneous state changes of two electrons and one nucleus. We identify different parameter regimes for effective polarization transfer and discuss under which conditions the polarization dynamics can be simulated by classical kinetic Monte Carlo methods. Our theoretical approach allows simulations of the polarization dynamics on an individual spin level for ensembles consisting of hundreds of nuclear spins. The insight obtained by these simulations can be used to find optimal experimental conditions for cross-effect DNP and to design tailored radical systems that provide optimal DNP efficiency

On Providing Cloud-awareness to Client's DASH Application by Using DASH over HTTP/2, Journal of Telecommunications and Information Technology, 2015, nr 4

Mobile Cloud Networks group together mobile users and clouds containing content servers. Hence, they are an ideal framework for media content delivery. Streams witching adaptive video players cope well with some limitations of Mobile Cloud Networks as low bandwidth and bandwidth variability in access network. Nonetheless, other limitations, as cloud congestion, are difficult to be managed by the video players. This paper presents a system for discovering fault situations at the cloud (e.g., cloud congestion) and notifying to the video player, which will take appropriate actions for saving the quality of media transmission. In proposed implementation the video application is DASH-capable and adaptation action may be both stream rate adaptation and content server adaptation. The communication between client and server uses \bidirectional" communication feature of HTTP/2 thanks to the new deployed modules running DASH over HTTP/2 in both client's and server's applications

Dynamic nuclear polarisation by thermal mixing: quantum theory and macroscopic simulations

A theory of dynamic nuclear polarisation (DNP) by thermal mixing is suggested based on purely quantum considerations. A minimal 6-level microscopic model is developed to test the theory and link it to the well known thermodynamic model. Optimal conditions for the nuclear polarization enhancement and effects of inhomogeneous broadening of the electron resonance are discussed. Macroscopic simulations of nuclear polarization spectra displaying good agreement with experiments, involving BDPA and trityl free radicals, are presented

The global spread of misinformation on spiders

Non peer reviewe

Budżetowanie działalności jednostek gospodarczych Teoria i praktyka. Część V

Z wprowadzenia: "Przekazujemy do rąk Czytelników część monografii dotyczącej budżetowania jednostek gospodarczych. Jej przygotowanie zbiegło się z ukazaniem się manifestu Precz z budżetami Jeremiego Норе’а i Robina Frasera. Autorzy poddają tam ostrej krytyce dotychczasowe praktyki stosowania budżetowania kosztowego. Stąd niniejsza publikacja - między innymi - dlatego różni się istotnie od poprzednich. Od pewnego czasu - także w Polsce - pojawiały się głosy wskazujące na istotne niedoskonałości budżetowania kosztowego, na przykład J. Gierusz [Materiały konferencyjne 2001], G. H. Świderska [Rachunkowośćzarządcza i rachunek kosztów, 2002]. Nie odnosiły one jednak skutku. Nie zauważono też dotąd narastającej listy zarzutów wytaczanych przeciw finansowym jednostkom miary stosowanym w budżetowaniu kosztowym, na przykład G. K. Świderska [jak wyżej], M. Sierpińska, B. Niedbała [Controllingoperacyjny wpnedsiębiorstwie, 2003]. Bez echa pozostało postawione przez autora pytanie: „zmierzch czy rozwój budżetowania?” [„Controlling i rachunkowość zarządcza” 9/2002], gdzie jednoznacznie wskazano, że budżetowanie kosztowe obejmuje jedynie jedną sferę działalności przedsiębiorstwa i tym samym nie może stanowić wystarczającej podstawy do sterowania przedsiębiorstwem. Zwolennicy budżetowania kosztowego nawet zgadzali się ze stawianymi zarzutami, jednak nie reagowali na propozycje zmian w filozofii i metodologii budżetowania."(...

An expert-curated global database of online newspaper articles on spiders and spider bites

Mass media plays an important role in the construction and circulation of risk perception associated with animals. Widely feared groups such as spiders frequently end up in the spotlight of traditional and social media. We compiled an expert-curated global database on the online newspaper coverage of human-spider encounters over the past ten years (2010–2020). This database includes information about the location of each human-spider encounter reported in the news article and a quantitative characterisation of the content—location, presence of photographs of spiders and bites, number and type of errors, consultation of experts, and a subjective assessment of sensationalism. In total, we collected 5348 unique news articles from 81 countries in 40 languages. The database refers to 211 identified and unidentified spider species and 2644 unique human-spider encounters (1121 bites and 147 as deadly bites). To facilitate data reuse, we explain the main caveats that need to be made when analysing this database and discuss research ideas and questions that can be explored with it. </p

The global spread of misinformation on spiders

In the internet era, the digital architecture that keeps us connected and informed may also amplify the spread of misinformation. This problem is gaining global attention, as evidence accumulates that misinformation may interfere with democratic processes and undermine collective responses to environmental and health crises. In an increasingly polluted information ecosystem, understanding the factors underlying the generation and spread of misinformation is becoming a pressing scientific and societal challenge. Here, we studied the global spread of (mis-)information on spiders using a high-resolution global database of online newspaper articles on spider–human interactions, covering stories of spider–human encounters and biting events published from 2010–2020. We found that 47% of articles contained errors and 43% were sensationalist. Moreover, we show that the flow of spider-related news occurs within a highly interconnected global network and provide evidence that sensationalism is a key factor underlying the spread of misinformation. </p