A precise determination of the Bc mass from dynamical lattice QCD

We perform a precise calculation of the mass of the B_c meson using unquenched configurations from the MILC collaboration including 2+1 flavours of improved staggered quarks. Lattice NRQCD and the Fermilab formalism are used to describe the b and c quarks respectively. We find the mass of the B_c meson to be 6.304(16) GeVComment: Talk presented at Lattice2004(heavy), Fermilab, June 21-26. 3 pages, 2 figure

How the composition of sandstone matrices affects rates of soil formation

Soils deliver multiple ecosystem services and their long-term sustainability is fundamentally controlled by the rates at which they form and erode. Our knowledge and understanding of soil formation is not commensurate with that of soil erosion, in part due to the difficulty of measuring the former. However, developments in cosmogenic radionuclide accumulation models have enabled soil scientists to more accurately constrain the rates at which soils form from bedrock. To date, all three major rock types – igneous, sedimentary and metamorphic lithologies – have been examined in such work. Soil formation rates have been measured and compared between these rock types, but the impact of rock characteristics on soil formation rates, such as rock matrices and mineralogy, have seldom been explored. In this UK-based study, we used cosmogenic radionuclide analysis to investigate whether the lithological variability of sandstone governs pedogenesis. Soil formation rates were measured on two arable hillslopes at Woburn and Hilton, which are underlain by different types of arenite sandstone. Rates were faster at Woburn, and we suggest that this is due to the fact that the Woburn sandstone formation is less cemented that that at Hilton. Similarly, rates at Woburn and Hilton were found to be faster than those measured at two other sandstone-based sites in the UK, and faster than those compiled in a global inventory of cosmogenic studies on sandstone-based soils. We suggest that the cementing agents present in matrix-abundant wackes studied previously may afford these sandstones greater structural integrity and resistance to weathering. This work points to the importance of factoring bedrock matrices into our understanding of soil formation rates, and the biogeochemical cycles these underpi

Intrusion prevention within a SDN environment

Recent investigations have highlighted the complexity and interrelationship between components of the infrastructure of the internet. In an attempt to simplify the management of the infrastructure a great deal of research has taken place in the area of Software Defined Networks (SDN). This paper investigates the perceived developments in the network infrastructure and how they can be accommodated with a SDN environment. In particular the deployment of Intrusion prevention, a well-known function found in most computer networks, is investigated. A hardware design is offered as a solution and it is shown how this can be integrated into a SDN.У статті звертається особлива увага на комплексність та взаємозв'язки між компонентами інфраструктури Інтернету. Для оптимізації управління даною інфраструктурою були проведені дослідження в області Software Defined мереж (SDN). У даній статті досліджуються значущі розробки для мережевої інфраструктури і способи їх розміщення в середовищі SDN. Зокрема, досліджується розгортання системи запобігання вторгнень, що є властивою більшості комп'ютерних мереж. Також запропоновано вирішення поставленого завдання за допомогою використання конструктивних особливостей апаратних засобів і методів їх інтеграції в SDN.В статье обращается особое внимание на комплексность и взаимосвязи между компонентами инфраструктуры Интернета. Для оптимизации управления данной инфраструктурой были проведены исследования в области Software Defined сетей (SDN). В данной статье исследуются значимые разработки для сетевой инфраструктуры и способы их размещения в среде SDN. В частности, исследуется развертывание системы предотвращения вторжений, присущей большинству компьютерных сетей. Также предложено решение поставленной задачи с помощью использования конструктивных особенностей аппаратных средств и методов их интеграции в SDN

Cryo-EM structures of human fucosidase FucA1 reveal insight into substrate recognition and catalysis

Enzymatic hydrolysis of α-L-fucose from fucosylated glycoconjugates is consequential in bacterial infections and the neurodegenerative lysosomal storage disorder fucosidosis. Understanding human α-L-fucosidase catalysis, in an effort toward drug design, has been hindered by the absence of three-dimensional structural data for any animal fucosidase. Here, we have used cryoelectron microscopy (cryo-EM) to determine the structure of human lysosomal α-L-fucosidase (FucA1) in both an unliganded state and in complex with the inhibitor deoxyfuconojirimycin. These structures, determined at 2.49 Å resolution, reveal the homotetrameric structure of FucA1, the architecture of the catalytic center, and the location of both natural population variations and disease-causing mutations. Furthermore, this work has conclusively identified the hitherto contentious identity of the catalytic acid/base as aspartate-276, representing a shift from both the canonical glutamate acid/base residue and a previously proposed glutamate residue. These findings have furthered our understanding of how FucA1 functions in both health and disease.Bio-organic Synthesi