Silicon-based resonant-cavity-enchanced photodiode with a buried SiO2 reflector

We report on a silicon-based resonant cavity photodiode with a buried silicon dioxide layer as the bottom reflector. The buried oxide is created by using a separation by implantation of oxygen technique. The device shows large Fabry-Perot oscillations. Resonant peaks and antiresonant troughs are observed as a function of the wavelength, with a peak responsivity of about 50 mA/W at 650 and 709 nm. The leakage current density is 85 pA/mm(2) at -5 V, and the average zero-bias capacitance is 12 pF/mm(2). We also demonstrate that the buried oxide prevents carriers generated deep within the substrate from reaching the top contacts, thus removing any slow carrier diffusion tail from the impulse response. (C) 1999 American Institute of Physics. (DOI: 10.1063/1.123499)

Can crop residues provide fuel for future transport? Limited global residue bioethanol potentials and large associated land, water and carbon footprints

Bioethanol production from non-crop based lignocellulosic material has reached the commercial scale and is advocated as a possible solution to decarbonize the transport sector. This study evaluates how much presently used transport related fossil fuels can be replaced with lignocellulosic bioethanol using crop residues, calculates greenhouse gas emission savings, and determines lignocellulosic bioethanol's land, water, and carbon footprints. We estimate global bioethanol production potential from 123 crop residues in 192 countries and 20 territories under different environmental constraints (optimistic and realistic sustainable potentials) versus no constraints (theoretical potential) on residue availability. Previous studies on global bioethanol production potential from lignocellulosic material focused on one or few biomass feedstocks, and excluded (un)constrained residue availability scenarios. Our results suggest the global net lignocellulosic bioethanol output ranges from 7.1 to 34.0 EJ per annum replacing between 7% and 31% of oil products for transport yielding relative emission savings of 338 megatonne (Mt; 70%) to 1836 Mt (79%). Emission savings range from 4% to 23% of total transport emissions in the realistic sustainable versus theoretical potential. Land, water and carbon footprints of net bioethanol vary between potentials, countries/territories, and feedstocks, but overall exceed footprints of conventional bioethanol. Averaged footprints range between 0.14 and 0.24 m2 land per megajoule (MJ−1), 74–120 L water MJ−1, and 28–44 g CO2 equivalent MJ−1, with smaller footprints in the theoretical potential caused by the exclusion of secondary residues and low price of alternative biomass chains in the sustainable potential

Double Lobed Radio Quasars from the Sloan Digital Sky Survey

We have combined a sample of 44984 quasars, selected from the Sloan Digital Sky Survey (SDSS) Data Release 3, with the FIRST radio survey. Using a novel technique where the optical quasar position is matched to the complete radio environment within 450", we are able to characterize the radio morphological make-up of what is essentially an optically selected quasar sample, regardless of whether the quasar (nucleus) itself has been detected in the radio. About 10% of the quasar population have radio cores brighter than 0.75 mJy at 1.4 GHz, and 1.7% have double lobed FR2-like radio morphologies. About 75% of the FR2 sources have a radio core (> 0.75 mJy). A significant fraction (~40%) of the FR2 quasars are bent by more than 10 degrees, indicating either interactions of the radio plasma with the ICM or IGM. We found no evidence for correlations with redshift among our FR2 quasars: radio lobe flux densities and radio source diameters of the quasars have similar distributions at low (mean 0.77) and high (mean 2.09) redshifts. Using a smaller high reliability FR2 sample of 422 quasars and two comparison samples of radio-quiet and non-FR2 radio-loud quasars, matched in their redshift distributions, we constructed composite optical spectra from the SDSS spectroscopic data. Based on these spectra we can conclude that the FR2 quasars have stronger high-ionization emission lines compared to both the radio quiet and non-FR2 radio loud sources. This is consistent with the notion that the emission lines are brightened by ongoing shock ionization of ambient gas in the quasar host as the radio source expands.Comment: 20 pages, 10 figures - some of which have been reduced in quality / size. Accepted for publication in the Astronomical Journa

Multiscale Bone Remodelling with Spatial P Systems

Many biological phenomena are inherently multiscale, i.e. they are characterized by interactions involving different spatial and temporal scales simultaneously. Though several approaches have been proposed to provide "multilayer" models, only Complex Automata, derived from Cellular Automata, naturally embed spatial information and realize multiscaling with well-established inter-scale integration schemas. Spatial P systems, a variant of P systems in which a more geometric concept of space has been added, have several characteristics in common with Cellular Automata. We propose such a formalism as a basis to rephrase the Complex Automata multiscaling approach and, in this perspective, provide a 2-scale Spatial P system describing bone remodelling. The proposed model not only results to be highly faithful and expressive in a multiscale scenario, but also highlights the need of a deep and formal expressiveness study involving Complex Automata, Spatial P systems and other promising multiscale approaches, such as our shape-based one already resulted to be highly faithful.Comment: In Proceedings MeCBIC 2010, arXiv:1011.005

Tackle your Tics:pilot findings of a brief, intensive group-based exposure therapy program for children with tic disorders

Tourette syndrome (TS) and other chronic tic disorders (CTD) are prevalent neurodevelopmental disorders, which can have a huge burden on families and society. Behavioral treatment is a first-line intervention for tic disorders. Despite demonstrated efficacy, tic reduction and utilization rates of behavioral treatment remain relatively low. Patient associations point to an urgent need for easy-to-undergo treatments that focus both on tic reduction and improvement of quality of life. To enhance treatment outcome and overcome treatment barriers, this pilot study's aim was to investigate the feasibility and preliminary results of a brief, intensive group-based treatment. Tackle your Tics is a 4-day intensive and comprehensive group-based program for children and adolescents (9-17 years) with a tic disorder, consisting of exposure and response prevention (ERP) treatment and additional supporting components, such as coping strategies, relaxing activities and parent support. Assessments were performed pre- and post-treatment and at 2 months follow-up, to test outcomes on tic severity and quality of life, and explore premonitory urges, emotional and behavioral functioning and treatment satisfaction (N = 14, of whom 13 completed the treatment). Parents and children rated this treatment positive on a treatment satisfaction questionnaire. On tic severity (Yale Global Tic Severity Scale) and quality of life (Gilles de la Tourette Syndrome Quality of Life Scale for children and adolescents), improvements between pre-treatment and follow-up were found. Intensive ERP in group format is promising as a feasible treatment to improve both tic severity as well as quality of life. Larger controlled trials are needed to establish its effectiveness

Bivariate stochastic modeling of functional response with natural mortality

A correction due to Abbott (1925) is the standard method of dealing with control mortality in insect bioassay to estimate the mortality of an insect conditional on control mortality not having occurred. In this article a bivariate stochastic process for overall mortality is developed in which natural mortality and predation are jointly modeled to take account of the competing-risks associated with prey loss. The total mortality estimate from this model is essentially identical with that from more classical modeling. However, when predation loss is estimated in the absence of control mortality the results are somewhat different, with the estimate from the bivariate model being lower than that from using Abbott’s formula in conjunction with the classical model. It is argued that overdispersion in observed mortality data corresponds to correlated outcomes (death or survival) for the prey initially present, while Abbott’s correction relies implicitly on independence

Economies of collaboration in build-to-model operations

This is the final version. Available from the publisher via the DOI in this record.The direct-from-model and tool-less manufacturing process of 3D printing (3DP) embodies a general-purpose technology, facilitating capacity sharing and outsourcing. Starting from a case study of a 3DP company (Shapeways) and a new market entrant (Panalpina), we develop dynamic practices for partial outsourcing in build-to-model manufacturing. We propose a new outsourcing scheme, bidirectional partial outsourcing (BPO), where 3D printers share capacity by alternating between the role of outsourcer and subcontractor based on need. Coupled with order book smoothing (OBS), where orders are released gradually to production, this provides 3D printers with two distinct ways to manage demand variability. By combining demand and cost field data with an analytical model, we find that BPO improves 3DP cost efficiency and delivery performance as the number of 3DP firms in the network increases. OBS is sufficient for an established 3D printer when alternatives to in-house manufacturing are few, or of limited capacity. Nevertheless, OBS comes at the cost of reduced responsiveness, whereas BPO shifts the cost and delivery performance frontier. Our analysis shows how BPO combined with OBS makes 3DP companies more resilient to downward movements in both demand and price levels.Innovate UKEngineering and Physical Sciences Research Council (EPSRC

Події революції 1905-1907 рр. та діяльність партії соціалістів-революціонерів на Чернігівщині

В запропонованій статті автор намагається розглянути взаємовплив народного та есерівського рухів на Лівобережній Україні в зазначений період. Метою дослідження є спроба аналізу тактики, методів, напрямків та динаміки діяльності партії соціалістів – революціонерів у Чернігівській губернії

Substructure lensing in galaxy clusters as a constraint on low-mass sterile neutrinos in tensor-vector-scalar theory: The straight arc of Abell 2390

Certain covariant theories of the modified Newtonian dynamics paradigm seem to require an additional hot dark matter (HDM) component - in the form of either heavy ordinary neutrinos or more recently light sterile neutrinos (SNs) with a mass around 11eV - to be relieved of problems ranging from cosmological scales down to intermediate ones relevant for galaxy clusters. Here we suggest using gravitational lensing by galaxy clusters to test such a marriage of neutrino HDM and modified gravity, adopting the framework of tensor-vector-scalar theory (TeVeS). Unlike conventional cold dark matter (CDM), such HDM is subject to strong phase-space constraints, which allows one to check cluster lens models inferred within the modified framework for consistency. Since the considered HDM particles cannot collapse into arbitrarily dense clumps and only form structures well above the galactic scale, systems which indicate the need for dark substructure are of particular interest. As a first example, we study the cluster lens Abell 2390 and its impressive straight arc with the help of numerical simulations. Based on our results, we outline a general and systematic approach to model cluster lenses in TeVeS which significantly reduces the calculation complexity. We further consider a simple bimodal lens configuration, capable of producing the straight arc, to demonstrate our approach. We find that such a model is marginally consistent with the hypothesis of 11eV SNs. Future work including more detailed and realistic lens models may further constrain the necessary SN distribution and help to conclusively assess this point. Cluster lenses could therefore provide an interesting discriminator between CDM and such modified gravity scenarios supplemented by SNs or other choices of HDM.Comment: 22 pages, 14 figures, 2 tables; minor changes to match accepted versio

First Test of Lorentz Invariance in the Weak Decay of Polarized Nuclei

A new test of Lorentz invariance in the weak interactions has been made by searching for variations in the decay rate of spin-polarized 20Na nuclei. This test is unique to Gamow-Teller transitions, as was shown in the framework of a recently developed theory that assumes a Lorentz symmetry breaking background field of tensor nature. The nuclear spins were polarized in the up and down direction, putting a limit on the amplitude of sidereal variations of the form |(\Gamma_{up} - \Gamma_{down})| / (\Gamma_{up} + \Gamma_{down}) < 3 * 10^{-3}. This measurement shows a possible route toward a more detailed testing of Lorentz symmetry in weak interactions.Comment: 11 pages, 6 figure