Recent advances and open challenges in percolation

Percolation is the paradigm for random connectivity and has been one of the most applied statistical models. With simple geometrical rules a transition is obtained which is related to magnetic models. This transition is, in all dimensions, one of the most robust continuous transitions known. We present a very brief overview of more than 60 years of work in this area and discuss several open questions for a variety of models, including classical, explosive, invasion, bootstrap, and correlated percolation

Multi-operability and dynamic bandwidth allocation in PONs with electrically reconfigurable SOA/REAM-based ONUs

An approach to integrate dynamic bandwidth allocation and multi-operability for WDM-PONs is demonstrated with a symmetrical SOA/REAM-based ONU design and C/L waveband 10Gb/s burst-mode operation, allowing electrical reconfigurability of the ONU's detection and remodulation branch

Recent advances and open challenges in percolation

Percolation is the paradigm for random connectivity and has been one of the most applied statistical models. With simple geometrical rules a transition is obtained which is related to magnetic models. This transition is, in all dimensions, one of the most robust continuous transitions known. We present a very brief overview of more than 60 years of work in this area and discuss several open questions for a variety of models, including classical, explosive, invasion, bootstrap, and correlated percolation

Hydrogenation reactions of carbon on Earth: Linking methane, margarine, and life

Hydrogenation reactions are a major route of electron and proton flow on Earth. Interfacing geology and organic chemistry, hydrogenations occupy pivotal points in the Earth’s global geochemical cycles. Some examples of hydrogenation reactions on Earth today include the production and consumption of methane in both abiotic and biotic reactions, the reduction of protons in hydrothermal settings, and the biological synthesis and degradation of fatty acids. Hydrogenation reactions were likely important for prebiotic chemistry on the early Earth, and today serve as one of the fundamental reaction classes that enable cellular life to construct biomolecules. An understanding and awareness of hydrogenation reactions is helpful for comprehending the larger web of molecular and material inter-conversions on our planet. In this brief review we detail some important hydrogenation and dehydrogenation reactions as they relate to geology, biology, industry, and atmospheric chemistry. Such reactions have implica- tions ranging from the suite of reactions on early Earth to industrial applications like the production of hydrocarbon fuel

Hydrogenation reactions of carbon on Earth: linking methane, margarine, and life

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in McGlynn, S. E., Glass, J. B., Johnson-Finn, K., Klein, F., Sanden, S. A., Schrenk, M. O., Ueno, Y., & Vitale-Brovarone, A. Hydrogenation reactions of carbon on Earth: linking methane, margarine, and life. American Mineralogist, 105(5), (2020): 599-608, doi:10.2138/am-2020-6928CCBYNCND.Hydrogenation reactions are a major route of electron and proton flow on Earth. Interfacing geology and organic chemistry, hydrogenations occupy pivotal points in the Earth’s global geochemical cycles. Some examples of hydrogenation reactions on Earth today include the production and consumption of methane in both abiotic and biotic reactions, the reduction of protons in hydrothermal settings, and the biological synthesis and degradation of fatty acids. Hydrogenation reactions were likely important for prebiotic chemistry on the early Earth, and today serve as one of the fundamental reaction classes that enable cellular life to construct biomolecules. An understanding and awareness of hydrogenation reactions is helpful for comprehending the larger web of molecular and material inter-conversions on our planet. In this brief review we detail some important hydrogenation and dehydrogenation reactions as they relate to geology, biology, industry, and atmospheric chemistry. Such reactions have implications ranging from the suite of reactions on early Earth to industrial applications like the production of hydrocarbon fuel.S.E.M. is supported by NSF Award 1724300 and JSPS KAKENHI Grant JP18H01325. A.V.B. is supported by ANR T-ERC, CNRS INSU-SYSTER, and Rita Levi Montalcini by MIUR. J.B.G. is supported by NASA Exobiology Grant NNX14AJ87G and 80NSSC19K0477. F.K. is supported by NSF-OCE award 1634032 and 1427274. M.O.S. is supported by the NASA Astrobiology Institute Rock-Powered Life Grant NNA15BB02A

Executive summary: "Mantle Frontier" workshop

The workshop on “Reaching the Mantle Frontier: Moho and Beyond� was held at the Broad Branch Road Campus of the Carnegie Institution of Washington on 9–11 September 2010. The workshop attracted seventy-four scientists and engineers from academia and industry in North America, Asia, and Europe.Reaching and sampling the mantle through penetration of the entire oceanic crust and the Mohorovi�ić discontinuity (Moho) has been a longstanding goal of the Earth science community. The Moho is a seismic transition, often sharp, from a region with compressional wave velocities (Vp) less than 7.5 km s-1 to velocities ~8 km s-1. It is interpreted in many tectonic settings, and particularly in tectonic exposures of oceanic lower crust, as the transition from igneous crust to mantle rocks that are the residues of melt extraction. Revealing the in situ geological meaning of the Moho is the heart of the Mohole project. Documenting ocean-crust exchanges and the nature and extent of the subseafloor biosphere have also become integral components of the endeavor. The purpose of the “Mantle Frontier� workshop was to identify key scientific objectives associated with innovative technology solutions along with associated timelines and costs for developments and implementation of this grandchallenge

Вплив екологічного стану Донецького регіону на його демографічний розвиток

В статті розглянуто важливу проблему впливу забрудненості навколишнього природного середовища на захворюваність та смертність в регіоні. Визначено кореляційну залежність між обсягом викидів забруднюючих речовин та окремими видами захворюваності, а також ступінь їх впливу, побудовано функції, що описують їх.В статье рассмотрена важная проблема влияния загрязненности окружающей естественной среды на заболеваемость и смертность в регионе. Определена корреляционная зависимость между объемом выбросов загрязняющих веществ и отдельными видами заболеваемости, а также степень их влияния, построены функции, которые описывают их.In the article the important problem of influence of muddiness of natural environment is considered on morbidity and death rate in a region. Certainly cross-correlation dependence between the volume of extrass of contaminents and separate types of morbidity, and also degree of their influence, functions which describe them are built. Keywords: environment

Fracturing ranked surfaces

Discretized landscapes can be mapped onto ranked surfaces, where every element (site or bond) has a unique rank associated with its corresponding relative height. By sequentially allocating these elements according to their ranks and systematically preventing the occupation of bridges, namely elements that, if occupied, would provide global connectivity, we disclose that bridges hide a new tricritical point at an occupation fraction $p=p_{c}$, where $p_{c}$ is the percolation threshold of random percolation. For any value of $p$ in the interval $p_{c}< p \leq 1$, our results show that the set of bridges has a fractal dimension $d_{BB} \approx 1.22$ in two dimensions. In the limit $p \rightarrow 1$, a self-similar fracture is revealed as a singly connected line that divides the system in two domains. We then unveil how several seemingly unrelated physical models tumble into the same universality class and also present results for higher dimensions