Successive Concave Sparsity Approximation for Compressed Sensing

In this paper, based on a successively accuracy-increasing approximation of the $\ell_0$ norm, we propose a new algorithm for recovery of sparse vectors from underdetermined measurements. The approximations are realized with a certain class of concave functions that aggressively induce sparsity and their closeness to the $\ell_0$ norm can be controlled. We prove that the series of the approximations asymptotically coincides with the $\ell_1$ and $\ell_0$ norms when the approximation accuracy changes from the worst fitting to the best fitting. When measurements are noise-free, an optimization scheme is proposed which leads to a number of weighted $\ell_1$ minimization programs, whereas, in the presence of noise, we propose two iterative thresholding methods that are computationally appealing. A convergence guarantee for the iterative thresholding method is provided, and, for a particular function in the class of the approximating functions, we derive the closed-form thresholding operator. We further present some theoretical analyses via the restricted isometry, null space, and spherical section properties. Our extensive numerical simulations indicate that the proposed algorithm closely follows the performance of the oracle estimator for a range of sparsity levels wider than those of the state-of-the-art algorithms.Comment: Submitted to IEEE Trans. on Signal Processin

Small Vessel Cerebrovascular Disease: The Past, Present, and Future

Brain infarction due to small vessel cerebrovascular disease (SVCD)—also known as small vessel infarct (SVI) or “lacunar” stroke—accounts for 20% to 25% of all ischemic strokes. Historically, SVIs have been associated with a favorable short-term prognosis. However, studies over the years have demonstrated that SVCD/SVI is perhaps a more complex and less benign phenomenon than generally presumed. The currently employed diagnostic and therapeutic strategies are based upon historical and contemporary perceptions of SVCD/SVI. What is discovered in the future will unmask the true countenance of SVCD/SVI and help furnish more accurate prognostication schemes and effective treatments for this condition. This paper is an overview of SVCD/SVI with respect to the discoveries of the past, what is known now, and what will the ongoing investigations evince in the future

Use of Hypertonic Continuous Venovenous Hemodiafiltration to Control Intracranial Hypertension in an End-Stage Renal Disease Patient

Continuous venovenous hemodiafiltration (CVVHDF) using solutions designed to maintain hypernatremia is described in an end-stage renal disease (ESRD) patient with cerebral edema (CE) due to an intracerebral hemorrhage (ICH). Hypernatremia was readily achieved and maintained without complication. CVVHDF should be considered as an alternative treatment option in ESRD patients with cerebral edema who require hypertonic saline therapy

Small Vessel Cerebrovascular Disease: The Past, Present, and Future

Brain infarction due to small vessel cerebrovascular disease (SVCD)-also known as small vessel infarct (SVI) or "lacunar" strokeaccounts for 20% to 25% of all ischemic strokes. Historically, SVIs have been associated with a favorable short-term prognosis. However, studies over the years have demonstrated that SVCD/SVI is perhaps a more complex and less benign phenomenon than generally presumed. The currently employed diagnostic and therapeutic strategies are based upon historical and contemporary perceptions of SVCD/SVI. What is discovered in the future will unmask the true countenance of SVCD/SVI and help furnish more accurate prognostication schemes and effective treatments for this condition. This paper is an overview of SVCD/SVI with respect to the discoveries of the past, what is known now, and what will the ongoing investigations evince in the future

Defoliation and its effect on morphology, biochemical parameters, yield and yield attributes of soybean

Loss of foliage in soybean crop through leaf eating insects and diseases is common in tropical and sub-tropical countries where farmers do not protect their crops adequately. Experiment was performed under sub-tropical condition (24°8' N, 90°0' E) with four levels of defoliations (0, 25, 50 and 75% from base of the canopy). Defoliations were imposed at the visible bud initiation stage to investigate the growth and yield attributes in two popular soybean varieties during January to April 2011. Results revealed that degrees of defoliations simultaneously decreased leaf area and total dry matter (TDM) production irrespective of varieties. Defoliation not only reduced source sizes but also decreased total sink (pod) production resulting in lower seed yields. However, basal 25% defoliation did not decrease TDM, seed weight/plant and seed yield/ha significantly indicating the fact that the soybean plant, in general, can tolerate 25% basal leaf loss of the canopy. Exceeding this threshold limit (>25%) of the canopy defoliation reduced TDM and seed yield significantly. Implication of the results in relation to pest management was also discussed

3-(Adamantan-1-yl)-1-[(4-ethyl­piperazin-1-yl)meth­yl]-4-[(E)-(4-hy­droxy­benzyl­idene)amino]-1H-1,2,4-triazole-5(4H)-thione

In the title thione, C26H36N6OS, the 1,2,4-triazole ring is planar (r.m.s. deviation = 0.020 Å) and the benzene ring is twisted out of this plane [dihedral angle = 62.35 (12)°]. Supra­molecular zigzag chains feature in the crystal packing. These are sustained by O—H⋯N(piperazine) hydrogen bonds, and are connected into the three-dimensional crystal structure by C—H⋯S and C—H⋯O inter­actions. The crystal studied was a racemic twin

3-(Adamantan-1-yl)-4-methyl-1-[(4-phenyl­piperazin-1-yl)meth­yl]-1H-1,2,4-triazole-5(4H)-thione dichloro­methane hemisolvate

The asymmetric unit of the title dichloro­methane hemisolvate, C24H33N5S·0.5CH2Cl2, comprises an adamantan­yl/triazole derivative and half a CH2Cl2 mol­ecule of crystallization; the latter is disordered about a twofold axis of symmetry. The piperazine ring has a chair conformation and the two N-bound substituents occupy equatorial positions. The piperazine residue is almost normal to the triazole ring [N—N—C—N torsion angle = −79.9 (3)°] so that to a first approximation, the mol­ecule has an L-shape. Linear supra­molecular chains parallel to [001] are formed via C—H⋯S inter­actions. Two such chains are linked into a double chain via C—H⋯Cl inter­actions involving the disordered CH2Cl2 mol­ecules of solvation

3-(Adamantan-1-yl)-1-[(4-benzyl­piperazin-1-yl)meth­yl]-4-[(E)-(2-hy­droxy­benzyl­idene)amino]-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C31H38N6OS, the conformation about the N=C [1.285 (2) Å] imine bond is E. The piperazine ring has a chair conformation and occupies a position almost perpendicular to the plane through the triazole ring; the benzene ring forms a dihedral angle of 31.95 (10)° with the triazole ring. Overall, the mol­ecule has the shape of a flattened bowl. The hy­droxy group is disordered over two positions. The major component has a site-occupancy factor of 0.762 (3) and forms an intra­molecular O—H⋯N(imine) bond to close an S(6) loop. The minor component of the disordered hy­droxy group forms an O—H⋯N(piperazine) hydrogen bond. These, along with C—H⋯S and C—H⋯N inter­actions, link mol­ecules into a three-dimensional architecture

Halotolerant microbial consortia for sustainable mitigation of salinity stress, growth promotion, and mineral uptake in tomato plants and soil nutrient enrichment

Salinity significantly impacts the growth, development, and reproductive biology of various crops such as vegetables. The cultivable area is reduced due to the accumulation of salts and chemicals currently in use and is not amenable to a large extent to avoid such abiotic stress factors. The addition of microbes enriches the soil without any adverse effects. The effects of microbial consortia comprising Bacillus sp., Delftia sp., Enterobacter sp., Achromobacter sp., was evaluated on the growth and mineral uptake in tomatoes (Solanum Lycopersicum L.) under salt stress and normal soil conditions. Salinity treatments comprising Ec 0, 2, 5, and 8 dS/m were established by mixing soil with seawater until the desired Ec was achieved. The seedlings were transplanted in the pots of the respective pH and were inoculated with microbial consortia. After sufficient growth, these seedlings were transplanted in soil seedling trays. The measurement of soil minerals such as Na, K, Ca, Mg, Cu, Mn, and pH and the Ec were evaluated and compared with the control 0 days, 15 days, and 35 days after inoculation. The results were found to be non-significant for the soil parameters. In the uninoculated seedlings’ (control) seedling trays, salt treatment significantly affected leaf, shoot, root dry weight, shoot height, number of secondary roots, chlorophyll, and mineral contents. While bacterized seedlings sown under saline soil significantly increased leaf (105.17%), shoot (105.62%), root (109.06%) dry weight, leaf number (75.68%), shoot length (92.95%), root length (146.14%), secondary roots (91.23%), and chlorophyll content (−61.49%) as compared to the control (without consortia). The Na and K intake were higher even in the presence of the microbes, but the beneficial effect of the microbe helps plants sustain in the saline environment. The inoculation of microbial consortia produced more secondary roots, which accumulate more minerals and transport substances to the different parts of the plant; thus, it produced higher biomass and growth. Results of the present study revealed that the treatment with microbial consortia could alleviate the deleterious effects of salinity stress and improve the growth of tomato plants under salinity stress. Microbial consortia appear to be the best alternative and cost-effective and sustainable approach for managing soil salinity and improving plant growth under salt stress conditions