Cornelissen, Milo D.
Pilon, Simone
Steemers, Luuk
Wanner, Martin J
Frölke, Steven
Zuidinga, Ed
Jorgensen, Steen Ingemann
van der Vlugt, Jarl Ivar
van Maarseveen, Jan H.
N,N-Carbonyldiimidazole (CDI), a common synthetic reagent used in commercial scale pharmaceutical synthesis, is known to be sensitive to hydrolysis from ambient moisture. This liability demands a simple, robust analytical method to quantitatively determine reagent quality to ensure reproducible performance in chemical reactions. This work describes a protocol for a rapid GC-FID based analysis of CDI. (C) 2016 Published by Elsevier B.V.
There is increasing concern about the replicability of studies in psychology and cognitive neuroscience. Hidden data dredging (also called p-hacking) is a major contributor to this crisis because it substantially increases Type I error resulting in a much larger proportion of false positive findings than the usually expected 5%. In order to build better intuition to avoid, detect and criticize some typical problems, here I systematically illustrate the large impact of some easy to implement and so, perhaps frequent data dredging techniques on boosting false positive findings. I illustrate several forms of two special cases of data dredging. First, researchers may violate the data collection stopping rules of null hypothesis significance testing by repeatedly checking for statistical significance with various numbers of participants. Second, researchers may group participants post hoc along potential but unplanned independent grouping variables. The first approach ‘hacks’ the number of participants in studies, the second approach ‘hacks’ the number of variables in the analysis. I demonstrate the high amount of false positive findings generated by these techniques with data from true null distributions. I also illustrate that it is extremely easy to introduce strong bias into data by very mild selection and re-testing. Similar, usually undocumented data dredging steps can easily lead to having 20–50%, or more false positives.
Miao Fuyou
Fan Yuanyuan
Wang Xingfu
Xiong Yan
Badawy, Moaman
Basic (t,n)-Secret sharing (SS) schemes share a secret among n shareholders by allocating each a share. The secret can be reconstructed only if at least t shares are available. An adversary without a valid share may obtain the secret when more than t shareholders participate in the secret reconstruction. To address this problem, the paper introduces the notion and gives the formal definition of (t, m, n)-Group oriented secret sharing (GOSS); and proposes a (t,m,n)-GOSS scheme based on Chinese remainder theorem. Without any share verification or user authentication, the scheme uses Randomized components (RC) to bind all participants into a tightly coupled group, and ensures that the secret can be recovered only if all m (m >=3D t) participants in the group have valid shares and release valid RCs honestly. Analysis shows that the proposed scheme can guarantee the security of the secret even though up to m-1 RCs or t-1 shares are available for adversaries. Our scheme does not depend on any assumption of hard problems or one way functions.
Chen, Yantao; Gradén, Henrik; Aurell, Carl-Johan; Gibson, James
N,N-Dimethylformamidines were synthesized from sulfonamides using the Vilsmeier reagent as a cleavage activator. The reactions were performed under mild conditions achieving good to excellent yields. The chemistry presented can also be used as a deprotection strategy when amines or anilines are protected with sulfonyl groups, such as the tosyl group.
Boxma, Onno
Claeys, Dieter
Gulikers, Lennart
Kella, Offer
This article is devoted to the study of an M/G/1 queue with a particular vacation discipline. The server is due to take a vacation as soon as it has served exactly N customers since the end of the previous vacation. N may be either a constant or a random variable. If the system becomes empty before the server has served N customers, then it stays idle until the next customer arrival. Such a vacation discipline arises, for example, in production systems and in order picking in warehouses. We determine the joint transform of the length of a visit period and the number of customers in the system at the end of that period. We also derive the generating function of the number of customers at a random instant, and the Laplace-Stieltjes transform of the delay of a customer. (c) 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 646-658, 2015
N^6-methyladenosine(m6A)is identified as the most widespread and abundant internal chemical modification of RNA in eukaryotes.A series of proteins including methyltransferases(also known as“writers”),demethylases(also known as“erasers”),and m6A-binding proteins(also known as“readers”)were indicated to participate in the m6A methylation.m6A has emerged as a regulator of various cellular,developmental,and disease processes.Notably,there is highest abundance of m^6A methylation in brain than in other organs,which indicates that m^6A plays an essential role in brain functions.Here,we describe the general features,mechanisms,and functions of m^6A in the brain,and discuss the emerging roles of m6A in brain physiology and diseases.
Anninos, Dionysios
Hartnoll, Sean A.
Huijse, Liza
Martin, Victoria L.
Large N matrices underpin the best understood models of emergent spacetime. We suggest that large N matrices can themselves be emergent from simple quantum mechanical spin models with finite dimensional Hilbert spaces. We exhibit the emergence of large N matrices in a nonlocal statistical physics model of order N-2 Ising spins. The spin partition function is shown to admit a large N saddle described by a matrix integral, which we solve. The matrix saddle is dominant at high temperatures, metastable at intermediate temperatures and ceases to exist below a critical order one temperature. The matrix saddle is disordered in a sense we make precise and competes with ordered low energy states. We verify our analytic results by Monte Carlo simulation of the spin system.
Thermogravimetric analysis coupled with IR spectroscopy was used to investigate the thermal stability and decomposition products of N,N-dialkylcarbamates of zirconium(IV), hafnium(IV), and niobium(IV), M(O2CNR2)(4). The niobium derivatives were less stable than the corresponding Zr(IV) and Hf(IV) derivatives, and the thermal stability was in the order of R =3D Et > Pr-i > Me. XRD analysis of the residue showed the formation of the oxides ZrO2 (tetragonal, P4 (2) /nmc), HfO2, (monoclinic, P2 (1)/c), and Nb2O5 (orthorhombic, Pbam). TEM analysis showed that all the oxides were obtained as nanopowders with a crystal size below 30 nm.
In cumulative and disjunctive constraint-based scheduling, the resource constraint is enforced by several filtering rules. Among these rules, we have (extended) edge-finding and not-first/not-last rules. The not-first/not-last rule detects tasks that cannot run first/last relatively to a set of tasks and prunes their time bounds. In this paper, it is presented a sound O (n (2) log n) algorithm for the cumulative not-first/not-last rule where n is the number of tasks. This algorithm reaches the same fix point as previous not-first/not-last algorithms, although it may take additional iterations to do so. The worst case complexity of this new algorithm for the maximal adjustment is the same as our previous complete O (n (2)|H| log n) not-first/not-last algorithm [7] where |H| is the maximum between the number of distinct earliest completion and latest start times of tasks. But, experimental results on benchmarks from the Project Scheduling Problem Library (PSPLib) and the Baptiste and Le Pape data set (BL) suggest that the new not-first/not-last algorithm has a substantially reduced runtime. Furthermore, the results demonstrate that in practice the new algorithm rarely requires more propagations than previous not-first/not-last algorithms.
We study the finite temperature properties of a recently introduced string bit model designed to capture some features of the emergent string in the tensionless limit. The model consists of a pair of bosonic and fermionic bit operators transforming in the adjoint representation of the color group SU(N). Color confinement is not achieved as a dynamical effect, but instead is enforced by an explicit singlet projection. At large N and finite temperature, the model has a non trivial thermodynamics. In particular, there is a Hagedorn type transition at a finite temperature T =3D T-H where the string degrees of freedom are liberated and the free energy gets a large contribution similar to N-2 that plays the role of an order parameter. For T > T-H, the low temperature phase becomes unstable. In the new phase, the thermodynamically favoured configurations are characterized by a non-trivial gapped density of the SU(N) angles associated with the singlet projection. We present an accurate algorithm for the determination of the density pro file at N =3D infinity. In particular, we determine the gap endpoint at generic temperature and analytical expansions valid near the Hagedorn transition as well as at high temperature. The leading order corrections are characterized by non-trivial exponents that are determined analytically and compared with explicit numerical calculations.
High levels of nitrogen (N) contamination of ground and surface water are still detected at European and national scales, despite the implementation of Directives, highlighting the need to improve understanding of changes in N pressure. Soil surface nitrogen balance was investigated at the county level in France over a 70-year period to identify areas with high N surpluses and trends in N pressure. Soil surface nitrogen balances were calculated for 90 NUTS3 (Nomenclature of Territorial Units for Statistics in the EU) called 'departments' (ranging from 611 to 10,145 km(2), median surface area 6032 km(2)) and one NUTS2 entity. Over the whole period, the N surplus calculated for France as a whole averaged 37 kgN per ha of utilized agricultural area (UAA) and departmental N surpluses mean ranged from 10 to 86 kgN ha UAA(-1). Imprecision, i.e. an 80% confidence interval in N surpluses, was calculated using Monte Carlo simulation. Average imprecision for the whole period ranged from 6 to 45 kgN ha UAA(-1) across different departments. Analysis revealed that yearly and departmental imprecision values were mainly correlated with N export (R-2 =3D 0.46). Despite this imprecision, the soil surface nitrogen balance was found to be a consistent and suitable tool to determine trends in N pressure at the department level. The model revealed an upward trend in N surplus until the 1990s for 82% of the area studied, and a downward or stable trend for more than 90% of the area since the European Nitrates Directive has been implemented.