Model Selection in High-Dimensional Block-Sparse Linear Regression

Model selection is an indispensable part of data analysis dealing very frequently with fitting and prediction purposes. In this paper, we tackle the problem of model selection in a general linear regression where the parameter matrix possesses a block-sparse structure, i.e., the non-zero entries occur in clusters or blocks and the number of such non-zero blocks is very small compared to the parameter dimension. Furthermore, a high-dimensional setting is considered where the parameter dimension is quite large compared to the number of available measurements. To perform model selection in this setting, we present an information criterion that is a generalization of the Extended Bayesian Information Criterion-Robust (EBIC-R) and it takes into account both the block structure and the high-dimensionality scenario. The analytical steps for deriving the EBIC-R for this setting are provided. Simulation results show that the proposed method performs considerably better than the existing state-of-the-art methods and achieves empirical consistency at large sample sizes and/or at high-SNR.Comment: 5 pages, 2 figure

Dimethyl 2,6-dimethyl-4-phenyl­pyridine-3,5-dicarboxyl­ate

In the title compound, C17H17NO4, the dihedral angle between the benzene and pyridine rings is 75.51 (4)°. The benzene and pyridine rings are both approximately planar (r.m.s. deviations of 0.0040 and 0.0083 Å, respectively), indicating that the pyridine N atom is not protonated. The crystal structure is stabilized by weak inter­molecular C—H⋯O and C—H⋯N inter­actions

5-(3,4-Dimeth­oxy­benzyl­idene)-1,3-dimethyl-1,3-diazinane-2,4,6-trione

In the title compound, C15H16N2O5, the dihedral angle between 1,3-diazinane and benzene rings is only 4.27 (1)°. The essentially planar mol­ecular structure is characterized by a short intra­molecular C—H⋯O separation and by an exceptionally large bond angle of 138.25 (14)° at the bridging methine C atom. The meth­oxy groups deviate somewhat from the plane of the benzene ring, with C—C—O—C torsion angles of −15.6 (1) and 9.17 (6)°. In the crystal, mol­ecules form centrosymmetric dimers via donor–acceptor π–π inter­actions, with a centroid–centroid distance of 3.401 (1) Å

Racemic tricarbon­yl[7-meth­oxy-2-(η6-phen­yl)chromane]­chromium(0)

In the title compound, [Cr(C16H16O2)(CO)3], the Cr0 atom of the Cr(CO)3 unit is coordinated to the phenyl ring of the flavan ligand in an η6 mode, with a normal arene-to-metal distance. The Cr(CO)3 unit exhibits a three-legged piano-stool conformation, while the dihydro­pyran ring displays a distorted envelope configuration. The phenyl ring is twisted away from the fused ring system by 25.5 (2)°. The meth­oxy group is almost coplanar with the phenyl ring [CMe—O—Car—Car torsion angle = 8.46 (2)°]. The crystal packing is stabilized by inter­molecular C—H⋯O inter­actions

Cloning and heterologous expression of a gene encoding lycopene-epsilon-cyclase, a precursor of lutein in tea (Camellia sinensis var assamica)

This report describes the cloning and expression of a gene lycopene epsilon cyclase, (LCYE) from Camellia sinensis var assamica which is a precursor of the carotenoid lutein in tea. The 1982 bp cDNA sequence with 1599 bp open reading frame of LCYE was identified from an SSH library constructed for quality trait in tea. 5’ and 3’ RACE (rapid-amplification of cDNA ends) was done to clone the full length cDNA of LCYE. Homology studies showed that the deduced amino acid sequence of LCYE gene had the highest sequence identity of up to 84% with Vitis vinefera. The cloned gene was successfully expressed in a PET based Escherichia coli expression system. The size of the expressed protein was 59615 Daltons. A suppression subtractive library was constructed using a quality clone H3111 (tester) and a garden series clone T3E3 (driver).Key words: Carotenoid, RACE, heterologous expression, lutein, tea

Timescapes of Himalayan hydropower: promises, project life cycles, and precarities

In this paper, we review the existing social science scholarship focused on hydropower development in the Himalayan region, using an interpretive lens attuned to issues of time and temporality. While the spatial politics of Himalayan hydropower are well examined in the literature, an explicit examination of temporal politics is lacking. In this paper, we present a conceptual framework organized around the heuristic of timescapes, highlighting temporal themes implicit in the existing literature. In three sections, we explore the temporal politics of anticipation that shape hydropower dreams, the intersecting temporalities and rhythms that modulate the life cycles of hydropower projects, and the ways that geological and hydrological time affect both hydropower development and broader Himalayan futures. Along the way, we pose a series of questions useful for framing future research given the significant climatic, geophysical, and sociopolitical changes underway in the Himalayan bioregion, calling for greater analytical attention to time, temporality, and temporal ethics in future studies of hydropower in the Himalayas and beyond.Austin Lord, Georgina Drew, Mabel Denzin Gerga