On the testability of coarsening assumptions: a hypothesis test for subgroup independence

Since coarse(ned) data naturally induce set-valued estimators, analysts often assume coarsening at random (CAR) to force them to be single-valued. Focusing on a coarse categorical response variable and a precisely observed categorical covariate, we re-illustrate the impossibility to test CAR and contrast it to another type of coarsening called subgroup independence (SI), using the data of the German Panel Study ``Labour Market and Social Security'' as an example. It turns out that -- depending on the number of subgroups and categories of the response variable -- SI can be point-identifying as CAR, but testable unlike CAR. A main goal of this paper is the construction of the likelihood-ratio test for SI. All issues are similarly investigated for the here proposed generalized versions, gCAR and gSI, thus allowing a more flexible application of this hypothesis test

Ethyl 1,3-dimethyl-1H-indole-2-carboxyl­ate

In the title compound, C13H15NO2, the plane of the indole ring forms a dihedral angle of 5.26 (6)° with the ester group and the ethyl side-chain C atoms. The crystal packing is stabilized by weak inter­molecular C—H⋯O and C—H⋯π inter­actions

Extractability and Intracellular Localisation of Urea Cycle Enzym es from Rat Liver

Peer Reviewe

pi-Extended Pyrene-Fused Double [7]Carbohelicene as a Chiral Polycyclic Aromatic Hydrocarbon

A π-extended double [7]carbohelicene 2 with fused pyrene units was synthesized, revealing considerable intra- and intermolecular π-πinteractions as confirmed with X-ray crystallography. As compared to the previous double [7]carbohelicene 1, the π-extended homologue 2 demonstrated considerably red-shifted absorption with an onset at 645 nm (1: 550 nm) corresponding to a smaller optical gap of 1.90 eV (1: 2.25 eV). A broad near-infrared emission from 600 to 900 nm with a large Stokes shift of ∼100 nm (2.3 × 103 cm-1) was recorded for 2, implying formation of an intramolecular excimer upon excitation, which was corroborated with femtosecond transient absorption spectroscopy. Moreover, 2 revealed remarkable chiral stability with a fairly high isomerization barrier of 46 kcal mol-1, according to density functional theory calculations, which allowed optical resolution by chiral HPLC and suggests potential applications in chiroptical devices

Nonlinear vertical oscillations of a particle in a sheath of a rf discharge

A new simple method to measure the spatial distribution of the electric field in the plasma sheath is proposed. The method is based on the experimental investigation of vertical oscillations of a single particle in the sheath of a low-pressure radio-frequency discharge. It is shown that the oscillations become strongly nonlinear and secondary harmonics are generated as the amplitude increases. The theory of anharmonic oscillations provides a good qualitative description of the data and gives estimates for the first two anharmonic terms in an expansion of the sheath potential around the particle equilibrium.Comment: 11 pages, 4 figure

2′-Hy­droxy­methyl-1′-(4-methyl­phen­yl)-2′-nitro-1′,2′,5′,6′,7′,7a′-hexa­hydro­spiro­[indoline-3,3′-pyrrolizin]-2-one

In the title compound, C22H23N3O4, the tolyl ring is almost perpendicular [83.86 (7)°] to the best plane through the eight atoms of the pyrrolizidine ring system. The mol­ecular conformation is stabilized by an intra­molecular O—H⋯O hydrogen bond. The crystal packing features inversion dimers with R 2 2(8) motifs linked by pairs of N—H⋯O hydrogen bonds

Towards a reliable categorical regression analysis for non-randomly coarsened observations: An analysis with German labour market data

In most surveys, one is confronted with missing or, more generally, coarse data. Many methods dealing with these data make strong, untestable assumptions, e.g. coarsening at random. But due to the potentially resulting severe bias, interest increases in approaches that only include tenable knowledge about the coarsening process, leading to imprecise, but credible results. We elaborate such cautious methods for regression analysis with a coarse categorical dependent variable and precisely observed categorical covariates. Our cautious results from the German panel study "Labour market and social security'' illustrate that traditional methods may even pretend specific signs of the regression estimates

Радиографический метод контроля сварных швов трубопроводов

Обнаружение дефектов сварных соединений является одной из основных задач неразрушающего контроля, применяемого для диагностики технического состояния трубопроводов различного назначения. Среди методов неразрушающего контроля широкое распространение получил радиографический метод. Для обработки изображений, полученных радиографическим методом, и обнаружения дефектов сварки, используются различные алгоритмы. Одним из перспективных алгоритмов обработки изображений является алгоритм, основанный на методе нейронной сети.Detection of defects in welded joints is one of the main tasks of non-destructive testing used for diagnostics of the technical condition of pipelines for various purposes. Among the methods of nondestructive testing, the radiographic method is widely used. For processing images obtained by radiographic method, and the detection of welding defects, various algorithms are used. One of the promising algorithms for image processing is an algorithm based on the neural network method

Distinct Regulatory Functions of Calpain 1 and 2 during Neural Stem Cell Self-Renewal and Differentiation

Calpains are calcium regulated cysteine proteases that have been described in a wide range of cellular processes, including apoptosis, migration and cell cycle regulation. In addition, calpains have been implicated in differentiation, but their impact on neural differentiation requires further investigation. Here, we addressed the role of calpain 1 and calpain 2 in neural stem cell (NSC) self-renewal and differentiation. We found that calpain inhibition using either the chemical inhibitor calpeptin or the endogenous calpain inhibitor calpastatin favored differentiation of NSCs. This effect was associated with significant changes in cell cycle-related proteins and may be regulated by calcium. Interestingly, calpain 1 and calpain 2 were found to play distinct roles in NSC fate decision. Calpain 1 expression levels were higher in self-renewing NSC and decreased with differentiation, while calpain 2 increased throughout differentiation. In addition, calpain 1 silencing resulted in increased levels of both neuronal and glial markers, β-III Tubulin and glial fibrillary acidic protein (GFAP). Calpain 2 silencing elicited decreased levels of GFAP. These results support a role for calpain 1 in repressing differentiation, thus maintaining a proliferative NSC pool, and suggest that calpain 2 is involved in glial differentiation