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A dedicated soil testing method for estimating available nitrogen (N) in organic production system is currently lacking. In this backdrop, an innovative approach was initiated to develop a suitable method for assessing potentially mineralisable nitrogen (PMN) as N availability index in organically fertilised soils. To address the objective, a field experiment was conducted in an organically fertilised french bean crop after a 3-year crop cycle of aromatic rice-french bean-okra. Farmyard manure, vermicompost, mustard oil-cake, poultry manure and their different combinations equivalent to 120 kg N ha−1 were applied as sources of N. Chemically fertilised plots were also maintained as a check. PMN was derived using first-order kinetics, from the disappearance of organic-N at different growth stages of french bean using the methods involving 1/15 M phosphate buffer (PB), 0.01 M calcium chloride (CaCl2), 0.01 M sodium bi-carbonate (NaHCO3), and 0.1 M sodium hydroxide + 0.05 M ethylenediaminetetraacetic acid (Basic EDTA) extractants. The conventional alkaline permanganate method for N estimation was also used for comparison. PB derived significantly 22, 39 and 47% higher PMN than Basic EDTA, NaHCO3 and CaCl2 respectively. PMNs estimated by different methods were well correlated (r = 0.53** to 0.84**) among themselves while exhibited poor correlation with alkaline permanganate N (r = 0.30 to 0.41*). PB-derived PMN depicted the strongest linear relationship with pod yield (r = 0.89**, R2 = 0.80**) and N uptake (r = 0.81**, R2 = 0.66**). The reliability of PB as the most suitable method was further established by principal component analysis as PB explained the highest proportion (73%) of total PMN variation. Beyond its consequential quantitative evaluation, the ability of PB to extract organic-N compounds of similar chemical nature (uniform C:N ratio, 12–14) from diverse organic sources confirmed its superiority. Adopting PB to estimate PMN as an index of N availability will thus assist soil testing agencies to improve nutrient management advisory for organic farmers.

We present here medium resolution (\lambda /\Delta\lambda\sim1200) H- and K-band spectra of M type dwarf stars covering the wavelength range 1.50 - 1.80 {\mu}m and 1.95 - 2.45 {\mu}m. The sample includes 53 dwarf stars (M0V-M7V) from new observations using the TIFR Near-Infrared Spectrometer and Imager (TIRSPEC) instrument on the 2-m Himalayan Chandra Telescope (HCT). Using interferometrically-measured effective temperature (T_{eff}), radius and luminosity of nearby bright calibrator stars, we have created new empirical relationships among those fundamental parameters and spectral indices. The equivalent widths of H-band spectral features like Mg (1.57 {\mu}m), Al (1.67 {\mu}m) and Mg (1.71 {\mu}m), and the H_{2}O-H index are found to be good indicators of T_{eff}, radius and luminosity and we establish the linear functions using these features relating to those stellar parameters. The root mean squared error (RMSE) of our best fits are 102K, 0.027R_{\sun} and 0.12dex respectively. Using spectral type standards along with known parallaxes, we calibrate both H and K-band H_{2}O indices as a tracer of spectral type and absolute K_{s} magnitude. Metallicities of M-dwarf samples are estimated using the K-band calibration relationships. The mass of M-dwarfs could be determined using the luminosity (L/L_{\sun}) and we establish a new empirical relation for this. We also compare and contrast our results with other similar work from the literature., Comment: 19 pages, 12 figures, accepted on February 08, 2020 for publication in Monthly Notices of the Royal Astronomical Society (MNRAS)

Phytophthora ramorum is a destructive pathogen that causes sudden oak death disease. The genome sequence of P. ramorum isolate Pr102 was previously produced, using Sanger reads, and contained 12 Mb of gaps. However, isolate Pr102 had shown reduced aggressiveness and genome abnormalities. In order to produce an improved genome assembly for P. ramorum, we performed long-read sequencing of highly aggressive P. ramorum isolate CDFA1418886 (abbreviated as ND886). We generated a 60.5-Mb assembly of the ND886 genome using the Pacific Biosciences (PacBio) sequencing platform. The assembly includes 302 primary contigs (60.2 Mb) and nine unplaced contigs (265 kb). Additionally, we found a ‘highly repetitive’ component from the PacBio unassembled unmapped reads containing tandem repeats that are not part of the 60.5-Mb genome. The overall repeat content in the primary assembly was much higher than the Pr102 Sanger version (48 versus 29%), indicating that the long reads have captured repetitive regions effectively. The 302 primary contigs were phased into 345 haplotype blocks and 222,892 phased variants, of which the longest phased block was 1,513,201 bp with 7,265 phased variants. The improved phased assembly facilitated identification of 21 and 25 Crinkler effectors and 393 and 394 RXLR effector genes from two haplotypes. Of these, 24 and 25 RXLR effectors were newly predicted from haplotypes A and B, respectively. In addition, seven new paralogs of effector Avh207 were found in contig 54, not reported earlier. Comparison of the ND886 assembly with Pr102 V1 assembly suggests that several repeat-rich smaller scaffolds within the Pr102 V1 assembly were possibly misassembled; these regions are fully encompassed now in ND886 contigs. Our analysis further reveals that Pr102 is a heterokaryon with multiple nuclear types in the sequences corresponding to contig 10 of ND886 assembly.

Soluble all-trans polyacetylenes (PAs) are most ideal models to study the spectroscopic properties of conjugated polymers for precise control of their backbone configurations, resulting in semiconducting properties for optoelectronic applications. Herein, we report precise control of the backbone configuration and subsequent self-assembly of soluble PAs flanked with alkyl–fluoroalkyl side chains, using light and temperature stimuli respectively in solution. PAs with symmetric alkyl and unsymmetrical alkyl–fluoroalkyl side chains were successfully polymerized by living cyclopolymerization with the olefin metathesis reaction mediated by third-generation Grubbs catalysts. Coil-to-rod-like conformational transition was observed for all of the PAs under ambient light due to photoisomerization, monitored by UV–vis spectroscopy and discussed in terms of the Huang–Rhys parameter. Enrichment of the trans configuration in the conjugated backbones opened up the possibility of aggregation between the isolated conjuga...

We test the Grumiller's quantum motivated modified gravity model, which at large distances modifies the Newtonian potential and describes the galactic rotation curves of disk galaxies in terms of a Rindler acceleration term without the need of any dark matter, against the baryonic Tully-Fisher feature that relates the total baryonic mass of a galaxy with flat rotation velocity of the galaxy. We estimate the Rindler acceleration parameter from observed baryonic mass versus rotation velocity data of a sample of sixty galaxies. Grumiller's model is found to describe the observed data reasonably well., 4 pages, two figures, To appear in Gravitation and Cosmology

We present here optical I-band photometric variability study down to $\simeq$ 19 mag of a young ($\sim$2-3 Myr) star-forming region IC 348 in the Perseus molecular cloud. We aim to explore the fast rotation (in the time-scales of hours) in Very Low Mass stars (VLMs) including Brown Dwarfs (BDs). From a sample of 177 light-curves using our new I-band observations, we detect new photometric variability in 22 young M-dwarfs including 6 BDs, which are bonafide members in IC 348 and well-characterized in the spectral type of M-dwarfs. Out of 22 variables, 11 M dwarfs including one BD show hour-scale periodic variability in the period range 3.5 - 11 hours and rest are aperiodic in nature. Interestingly, an optical flare is detected in a young M2.75 dwarf in one night data on 20 December 2016. From the flare light curve, we estimate the emitted flared energy of 1.48 $\times$ 10$^{35}$ ergs. The observed flared energy with an uncertainty of tens of per cent is close to the super-flare range ($\sim$ 10$^{34}$ ergs), which is rarely observed in active M dwarfs., 12 pages, 5 figures

We present results of our study of two planetary nebulae (PNe), PB1 and PC 19. We use the optical spectra of these two PNe observed at 2 m Himalayan Chandra Telescope and also archival and literature data for the study. We use the morphokinematic code SHAPE to construct 3D morphologies of the PNe and the photoionization code CLOUDY to model the observed spectra. The 3D model of PB 1 consists of an elongated shell surrounded by a bipolar halo and that of PC 19 consists of an open lobed bipolar structure and a spiral filamentary pair. We analyze the ionization structure of the PNe by deriving several plasma parameters and by photoionization modelling. We estimate the elemental abundances of the the elements, He, C, N, O, Ne, S, Ar, and Cl, from our analysis. We find He, C and N abundances to be significantly higher in case of PB 1. We estimate different physical parameters of the central stars, namely effective temperature, luminosity and gravity, and of the nebula, namely hydrogen density profiles, radii, etc., from photoionization modelling. We estimate distances to the PNe as $\sim$4.3 kpc for PB 1 and as $\sim$5.6 kpc for PC 19 by fitting the photoionization models to absolute observed fluxes. Progenitor masses are estimated from theoretical evolutionary trajectories and are found to be $\sim$1.67 and $\sim$2.38 $M_{\odot}$ for PB 1 and PC 19, respectively., 20 pages, 14 figures, 9 tables

Endophytic yeasts of genus Rhodotorula are gaining importance for their ability to improve plant growth. The nature of their interaction with plants, however, remains unknown. Rhodotorula mucilaginosa JGTA-S1 was isolated as an endophyte of Typha angustifolia and promoted growth in the host. To investigate the life-strategy of the yeast from a genomics perspective, we used Illumina and Oxford Nanopore reads to generate a high-quality annotated draft assembly of JGTA-S1 and compared its genome to three other Rhodotorula yeasts and the close relative Rhodosporidium toruloides. JGTA-S1 is a haploid yeast possessing several genes potentially facilitating its endophytic lifestyle such as those responsible for solubilizing phosphate and producing phytohormones. An intact mating-locus in JGTA-S1 raised the possibility of a yet unknown sexual reproductive cycle in Rhodotorula yeasts. Additionally, JGTA-S1 had functional anti-freezing genes and was also unique in lacking a functional nitrate-assimilation pathway—a feature that is associated with obligate biotrophs. Nitrogen-fixing endobacteria were found within JGTA-S1 that may circumvent this defective N-metabolism. JGTA-S1 genome data coupled with experimental evidence give us an insight into the nature of its beneficial interaction with plants.

Reversible covalent bond formation/scission systems, referred to as Dynamic Covalent Chemistry (DCC), have received significant interest in view of the molecular systems, which offer feasible “error-correction” of the targeted chemical structures and the rearrangement of chemical bonds into the proper manner during the synthetic processes. DCC has been widely designed and developed with molecules in chemical equilibria where a set of reactants and a product are both in closed shell molecules. Within a few years, the concept of DCC systems has been extended to the formation of a covalent bond between a set of stable radicals, utilizing a common feature of radical species: the ease of the bond cleavage and formation. Generally, the coupling reactions among radical species are thermodynamically favorable in a down-hill manner with no or extremely small energetic barriers, and the barrier of the dissociation reactions can be minimized by properly designing the radical species. This review highlights the examples of the radicals showing reversible oligomerization–dissociation behavior, which have been or will potentially be utilized as building blocks in DCC, and the recent development of molecular self-assembly based on reversible radical coupling and homolytic cleavage reactions.

Self-assembled π-conjugated molecules exhibit switching between crystalline–amorphous nanostructures, attracting significant interest in the field of organic electronics, particularly memory devices. Herein, we report ferrocene-appended tetratolylporphyrin, H2TTP-Fc, which undergoes protonation in 1,2-dichloroethane via sonication and reverses to the original state by deprotonation with time, as confirmed by optical and electrochemical properties. Absorption spectra reveal the selectivity of reversible and irreversible protonation of H2TTP-Fc in halogenated solvents and mineral acids. Microscopic analysis suggested that H2TTP-Fc aggregates exhibit a crystalline flower-like morphology from the joining of 2D microsheets, whereas H4TTP-Fc forms nanospheres with an average diameter of 150–200 nm upon methanol vapor diffusion (MVD). Electrochemical properties of H4TTP-Fc films reveal the ease of oxidation when compared to that in the solution state as a result of high current generation at less work function. ...

Merchant shipping is moving more than 10 billion tons of ballast water around the world annually, placing human health at risk and causing ecological and environmental damage through the transportation of pathogens and marine aquatic species. The International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWM Convention) adopted by the International Maritime Organization (IMO) to address this issue, is set to enter into force on the 8 September 2017. Once the Convention enters into force, seafarers conducting ballast water management (BWM) operations will need in-depth knowledge of the Convention and be proficient with standards and best practices. Lack of competence will have serious implications for seafarers (e.g. health hazards and financial penalties); and damage to the marine environment. Based on a perception survey of 25 seafarer students enrolled in their final year of training at the Australian Maritime College (AMC), this research investigates the effectiveness of maritime training providers in delivering training for seafarers certified for operational and management levels of competence, to effectively comply with the BWM Convention. The student perceptions indicated that majority of the students are satisfied with elements of BWM training which are being delivered by the AMC.

The rod-like configuration of conjugated polymer chains with its low energetic disorder is the key to utilizing the backbone as a highly electrically-conductive wire. An energetic disorder that is higher than 0.1 eV, coupled with vibronic modes of the chains, leads to the localization of charges. Herein, we have tracked precisely the rod-like transition of poly(p-phenyleneethynylene) (PPE) chains as a function of temperature in diluted solutions, and shown a steep increase in persistence length at 230 K. The resulting rod-like configuration of the PPE chains with its extended electronic conjugation exhibited an extremely small energetic disorder of ∼70 meV, and was stabilized by subsequent polymer aggregate formation.

We report an unprecedented strategy to generate and amplify near-infrared (NIR) emission in an organic chromophore by mechanical stress or gelation pathways. A greenish-yellow emitting film of π-extended Bodipy-1, obtained from n-decane, became orange-red upon mechanical shearing, with a 15-fold enhancement in NIR emission at 738 nm. Alternatively, a DMSO gel of Bodipy-1 exhibited a 7-fold enhancement in NIR emission at 748 nm with a change in emission color from yellow to orange-red upon drying. The reason for the amplified NIR emission in both cases is established from the difference in chromophore packing, by single crystal analysis of a model compound (Bodipy-2), which also exhibited a near identical emission spectrum with red to NIR emission (742 nm). Comparison of the emission features and WAXS and FT-IR data of the sheared n-decane film and the DMSO xerogel with the single crystal data supports a head-to-tail slipped arrangement driven by the N–H⋯F–B bonding in the sheared or xerogel states, which facilitates strong exciton coupling and the resultant NIR emission.

π-Gels are a promising class of functional soft materials formed out of short π-conjugated molecules. By utilizing the chemistry of noncovalent interactions, researchers have created a wide range of π-gels that are composed of supramolecular polymers. During the last two decades, supramolecular gel chemistry has been pursued with the hope of developing new materials for applications in, for example, organic electronics, energy harvesting, sensing, and imaging. The high expectations for π-gels were centered mainly around their electronic properties, such as tunable emission, energy transfer, electron transfer, charge transport, and electrical conductivity; such properties are amenable to modulation through size and shape control of molecular assemblies. Although a large number of exciting publications have appeared, a major technological breakthrough is yet to be realized. In this review, we analyze the recent advancements in the area of functional π-gels and their scope in future applications.

The very concept of dye and pigment chemistry that was long known to the industrial world underwent a radical revision after the discovery and commercialization of dyes such as mauveine, indigo, and so on. Apart from their conventional role as coloring agents, organic dyes, and pigments have been identified as indispensable sources for high-end technological applications including optical and electronic devices. Simultaneous with the advancement in the supramolecular chemistry of π-conjugated systems and the divergent evolution of organic semiconductor materials, several dyes, and pigments have emerged as potential candidates for contemporary optoelectronic devices. Of all the major pigments, diketopyrrolopyrrole (DPP) better known as the ‘Ferrari Pigment’ and its derivatives have emerged as a major class of organic functional dyes that find varied applications in fields such as industrial pigments, organic solar cells, organic field–effect transistors, and in bioimaging. Since its discovery in 1974 by Farnum and Mehta, DPP-derived dyes gained rapid attention because of its attractive color, synthetic feasibility, ease of functionalization, and tunable optical and electronic properties. The advancement in supramolecular polymerization of DPP-based small molecules and oligomers with directed morphological and electronic features have led to the development of high performing optoelectronic devices. In this review, we highlight the recent developments in the optoelectronic applications of DPP derivatives specifically engineered to form supramolecular polymers.

The expression of gravitational time advancement (negative time delay) for particles with non-zero mass in Schwarzschild geometry has been obtained. The influences of the gravitational field that describes the observed rotation curves of spiral galaxies and that of dark energy (in the form of cosmological constant) on time advancement of particles have also been studied. The present findings suggest that in presence of dark matter gravitational field the time advancement may take place irrespective of gravitational field of the observer, unlike the case of pure Schwarzschild geometry where gravitational time advancement takes place only when the observer is situated at stronger gravitational field compare to the gravitational field encountered by the particle during its journey. When applied to the well known case of SN 1987a, it is found that the net time delay of a photon/gravitational wave is much smaller than quoted in the literature. In the presence of dark matter field, the photon and neutrinos from SN 1987a should have been suffered gravitational time advancement rather than the delay., Comment: 13 pages, 1 figure

Organic semiconductors with variable charge carrier polarity are required for optoelectronic applications. Herein, we report the synthesis of three novel diketopyrrolopyrrole (DPP)-based D–A molecules having three different terminal groups (amide, ester, and dicyano) and study their electronic properties. An increase in electron acceptor strength from amide to dicyano leads to a bathochromic shift in absorption. Photoconductivity and field effect transistor (FET) measurements confirmed that a small increase in acceptor strength can result in a large change in the charge transport properties from p-type to n-type. The molecule with an amide group, DPP–amide, exhibited a moderate p-type mobility (1.3 × 10–2 cm2 V–1 s–1), whereas good n-type mobilities were observed for molecules with an ester moiety, DPP–ester (1.5 × 10–2 cm2 V–1 s–1), and with a dicyano group, DPP–DCV (1 × 10–2 cm2 V–1 s–1). The terminal functional group modification approach presented here is a simple and efficient method to alter the cha...

The design of fluorescent molecular platforms capable of responding to multiple analytes is a topic of great interest. Herein, the use of a Zn2+ -complexed unsymmetrical squaraine dye, Sq-Zn2+ , as a chemical platform for recognizing structurally distinct analytes is reported. The squaraine ring is substituted on one side with a dipicolylamine unit, which acts as the metal ion receptor, whereas the other part of the molecule carries a dibutylaniline moiety, which is an electron donor. The molecular system is unique because it can respond specifically to different types of analytes, namely, atmospheric carbon dioxide, cyclic phosphates, and picric acid. Moreover, the interaction of these analytes can be monitored colorimetrically and fluorimetrically, which favors both qualitative and quantitative analyses. The distinct response towards cyclic and linear phosphates, as well as the selective response towards picric acid, among the various nitroaromatic compounds was achieved with sensitivity at the ppm level. The flexible coordination offered by Zn2+ plays a significant role in the discrimination of these analytes with high specificity. Dye Sq-Zn2+ introduced herein is a single-molecule construct that can be used for the selective and sensitive response towards analytes of environmental and biological relevance.

A π-conjugated amphiphilic diketopyrrolopyrrole (PDPP-Amphi) forms crystalline 2D supramolecular nanosheets in water when compared to that from methyl cyclohexane. These nanosheets exhibit high fluorescence quantum yield in the solid-state with anisotropic charge-carrier mobility of 0.33 cm2 V-1 s-1 .

Charge-transfer (CT) complexes of near-infrared absorbing systems have been unknown until now. Consequently, structural similarities between donor and acceptor are rather important to achieve this phenomenon. Herein, we report electron donors such as non-fused diporphyrin-anthracene (DP), zinc diporphyrin-anthracene (ZnDP) and fused zinc diporphyrin-anthracene (FZnDP) in which FZnDP absorbs in NIR region and permits a CT complex with the electron acceptor, perylene diimide (PDI) in CHCl3 exclusively. UV/Vis-NIR absorption, 1H NMR, NOESY and powder X-ray diffraction analysis demonstrated that the CT complex formation occurs by π–π stacking between perylene units in FZnDP and PDI upon mixing together in a 1:1 molar concentration in CHCl3, unlike non-fused ZnDP and DP. TEM and AFM images revealed that the CT complex initially forms nanospheres leading to nanorods by diffusion of CH3OH vapors into the CHCl3 solution of FZnDP/PDI (1:1 molar ratio). Therefore, these CT nanorods could lead to significant advances in optical, biological and ferroelectric applications.