924 research outputs found
Solution of the symmetric eigenproblem AX=lambda BX by delayed division
Delayed division is an iterative method for solving the linear eigenvalue problem AX = lambda BX for a limited number of small eigenvalues and their corresponding eigenvectors. The distinctive feature of the method is the reduction of the problem to an approximate triangular form by systematically dropping quadratic terms in the eigenvalue lambda. The report describes the pivoting strategy in the reduction and the method for preserving symmetry in submatrices at each reduction step. Along with the approximate triangular reduction, the report extends some techniques used in the method of inverse subspace iteration. Examples are included for problems of varying complexity
Detection of SiO emission from a massive dense cold core
We report the detection of the SiO (J = 2 - 1) transition from the massive
cold dense core G333.125-0.562. The core remains undetected at wavelengths
shorter than 70 micron and has compact 1.2 mm dust continuum. The SiO emission
is localised to the core. The observations are part of a continuing
multi-molecular line survey of the giant molecular cloud G333. Other detected
molecules in the core include 13CO, C18O, CS, HCO+, HCN, HNC, CH3OH, N2H+, SO,
HC3N, NH3, and some of their isotopes. In addition, from NH3 (1,1) and (2,2)
inversion lines, we obtain a temperature of 13 K. From fitting to the spectral
energy distribution we obtain a colour temperature of 18 K and a gas mass of 2
x 10^3 solar mass. We have also detected a 22 GHz water maser in the core,
together with methanol maser emission, suggesting the core will host massive
star formation. We hypothesise that the SiO emission arises from shocks
associated with an outflow in the cold core.Comment: 6 pages, 4 figures, 1 table, to be published in MNRA
Agronomic performance of Indian wheat varieties and genetic stocks known for outstanding chapati quality characteristics
The aim of the present study was to evaluate set of wheat genotypes in one location for their agronomic performance and chapati quality. The cultivars included the tall traditional wheat of the pre-dwarfing era, which were known to excel for chapati quality. This set also included varieties known to have good chapati quality, commercially grown wheats, advanced lines and genetic stocks excelling in one or other quality attribute. All these genotypes developed for different component traits were evaluated along with the recently released high yielding varieties to assess their quality. The mean chapati score of these genotypes revealed that the tall varieties had a distinct edge over others and are the best resource available for this trait. C306 had a high mean chapati score of 8.17 followed by C518, C591 and C273. The released varieties WG357, HD2733 and PBW343 were intermediate in chapati quality whereas the genetic stocks WH1103 and WH712 had lowest score in the group. Among other agronomic traits recorded the traditional varieties were tall and had lower yields than the recently released varieties. The tall varieties had a slightly higher test weight. The environmental conditions and the quantitative nature of the chapati quality did not auger well with the set of genotypes tested however, better and stable performance of the tall traditional varieties. C306 the wheat variety released in 1965 for cultivation has remained the best quality genotype over the years and was also established from this study
Development of near isogenic lines (NILS) using backcross method of breeding and simultaneous screening against Karnal bunt disease of wheat
Karnal bunt of wheat caused by Tilletia indica can be a hindrance to wheat trade as the fungal disease is known to affect the quality of the grain. As a breeding strategy, a set of eight near isogenics lines (NILs) and backcross derived recombinant inbred lines (micro-RILs) were developed in the background of PBW 343 and WH542 for Karnal bunt resistance over a period of time. The donor stocks resistant to Karnal bunt used in the study were ALDAN ‘ S’ / IAS 58, CMH 77.308, H567.7I, HD29, HP1531, W485 and their derived lines KBRL 22 and KBRL 57. Effective method for screening to Karnal bunt was standardized and used for identification of resistant lines across many seasons. Some of the identified lines evaluated for yield were found to be equivalent to the high yielding parents and the commercially grown check varieties. These developed lines will serve as a basic material for production of Karnal bunt free wheat
Observations and radiative transfer modelling of a massive dense cold core in G333
Cold massive cores are one of the earliest manifestations of high mass star
formation. Following the detection of SiO emission from G333.125-0.562, a cold
massive core, further investigations of the physics, chemistry and dynamics of
this object has been carried out. Mopra and NANTEN2 molecular line profile
observations, Australia Telescope Compact Array (ATCA) line and continuum
emission maps, and Spitzer 24 and 70 \mum images were obtained. These new data
further constrain the properties of this prime example of the very early stages
of high mass star formation. A model for the source was constructed and
compared directly with the molecular line data using a 3D molecular line
transfer code - MOLLIE. The ATCA data reveal that G333.125-0.562 is composed of
two sources. One of the sources is responsible for the previously detected
molecular outflow and is detected in the Spitzer 24 and 70 \mum band data.
Turbulent velocity widths are lower than other more active regions of G333
which reflects the younger evolutionary stage and/or lower mass of this core.
The molecular line modelling requires abundances of the CO isotopes that
strongly imply heavy depletion due to freeze-out of this species onto dust
grains. The principal cloud is cold, moderately turbulent and possesses an
outflow which indicates the presence of a central driving source. The secondary
source could be an even less evolved object as no apparent associations with
continuum emissions at (far-)infrared wavelengths.Comment: 10 pages, accepted to MNRA
Effect of stem reserve mobilization on grain filling under drought stress conditions in recombinant inbred population of wheat
Pre-anthesis carbon assimilation of stem reserves is considered as an important source for grain filling during post anthesis drought stresses that inhibit photosynthesis. 175 RILs from cross (C518/2*PBW343) along with check cultivars were evaluated for stem reserve mobilization under irrigated and rainfed conditions. These two cultivars belonging to distinct adaptation mechanism, offer several morpho -physiological and biochemical con-trasts. C 518 is tall and adapted to low input rainfed conditions whereas PBW 343 is semi -dwarf and input re-sponsive. Further C 518 is known for better stem reserves on account of larger peduncle and strong commitment to grain filling due to effective stem reserve mobilization. The parents and the RIL population was tested for stem reserve mobilization by defoliation of flag leaf and second leaf at anthesis under irrigated and rainfed environments. Evaluated entries differed significantly (p<0.001) for reduction in 1000 grain weight under defoliation (TGWL). Percent reduction in 1000 grain weight ranged from 4.4 % to 39.6 % under irrigated environment and 3.2 % to 35.0 under rainfed condition. A significant positive correlation (r = +0.357) between stem reserve mobilization and peduncle length was observed under rainfed condition. Tested RILs vary individually for stem reserve mobilization when subjected to removal of flag leaf and second leaf inhibiting the photosynthesis. The genotypes with better stem reserve mobilization based on 1000 grain weight in the absence of photosynthesis may also provide relative tolerance to drought
Effects of cutouts on the behavior of symmetric composite laminates subjected to bending and twisting loads
Composite structures are used for a wide variety of aerospace applications. Practical structures contain cutouts and these structures are subjected to in-plane and out-of-plane loading conditions. Structurally efficient designs for composite structures require a thorough understanding of the effects of cutouts on the response of composite plates subjected to inplane or out-of-plane loadings. Most investigations of the behavior of composite plates with cutouts have considered in-plane loadings only. Out-of-plane loadings suchas bending or twisting have received very limited attention. The response of homogeneous plates (e.g., isotropic or orthotropic plates) subjected to bending or twisting moments has been studied analytically. These analyses are for infinite plates and neglect finite-plate effects. Recently, analytical and experimental studies were conducted to determine the effects of cutouts on the response of laminated composite plates subjected to bending moments. No analytical or experimental results are currently available for the effects of cutouts on the response of composite laminates subjected to twisting moments
Possibilities for an Aerial Biosphere in Temperate Sub Neptune-Sized Exoplanet Atmospheres
The search for signs of life through the detection of exoplanet atmosphere
biosignature gases is gaining momentum. Yet, only a handful of rocky exoplanet
atmospheres are suitable for observation with planned next-generation
telescopes. To broaden prospects, we describe the possibilities for an aerial,
liquid water cloud-based biosphere in the atmospheres of sub Neptune-sized
temperate exoplanets, those receiving Earth-like irradiation from their host
stars. One such planet is known (K2-18b) and other candidates are being
followed up. Sub Neptunes are common and easier to study observationally than
rocky exoplanets because of their larger sizes, lower densities, and extended
atmospheres or envelopes. Yet, sub Neptunes lack any solid surface as we know
it, so it is worthwhile considering whether their atmospheres can support an
aerial biosphere. We review, synthesize, and build upon existing research.
Passive microbial-like life particles must persist aloft in a region with
liquid water clouds for long enough to metabolize, reproduce, and spread before
downward transport to lower altitudes that may be too hot for life of any kind
to survive. Dynamical studies are needed to flesh out quantitative details of
life particle residence times. A sub Neptune would need to be a part of a
planetary system with an unstable asteroid belt in order for meteoritic
material to provide nutrients, though life would also need to efficiently reuse
and recycle metals. The origin of life may be the most severe limiting
challenge. Regardless of the uncertainties, we can keep an open mind to the
search for biosignature gases as a part of general observational studies of sub
Neptune exoplanets.Comment: Published in Universe: https://www.mdpi.com/2218-1997/7/6/17
The EV-olution of the power system: a spatio-temporal optimisation model to investigate the impact of electric vehicle deployment
Power system models have become an essential part of strategic planning and decision-making in the energy transition. While techniques are becoming increasingly sophisticated and manifold, the ability to incorporate high resolution in space and time with long-term planning is limited. We introduce ESONE, the Spatially granular Electricity Systems Optimisation model. ESONE is a mixed-integer linear program, determining investment in power system generation and transmission infrastructure while simultaneously optimising operational schedule and optimal power flow on an hourly basis. Unique data clustering combined with model decomposition and an iterative solution procedure enable computational tractability. We showcase the capabilities of the ESONE model by applying it to the power system of Great Britain under CO2 emissions reduction targets. We investigate the effects of a spatially distributed large-scale roll-out of electric vehicles (EVs). We find EV demand profiles correlate well with offshore and onshore wind power production, reducing curtailment and boosting generation. Time-of-use-tariffs for EV charging can further reduce power supply and transmission infrastructure requirements. In general, Great Britain’s electricity system absorbs additional demand from ambitious deployment of EVs without substantial changes to system design
Contrasting exome constancy and regulatory region variation in the gene encoding CYP3A4: an examination of the extent and potential implications.
OBJECTIVE: CYP3A4 expression varies up to 100-fold among individuals, and, to date, genetic causes remain elusive. As a major drug-metabolizing enzyme, elucidation of such genetic causes would increase the potential for introducing personalized dose adjustment of therapies involving CYP3A4 drug substrates. The foetal CYP3A isoform, CYP3A7, is reported to be expressed in ∼10% of European adults and may thus contribute towards the metabolism of endogenous substances and CYP3A drug substrates. However, little is known about the distribution of the variant expressed in the adult. METHODS: We resequenced the exons, flanking introns, regulatory elements and 3'UTR of CYP3A4 in five Ethiopian populations and incorporated data from the 1000 Genomes Project. Using bioinformatic analysis, we assessed likely consequences of observed CYP3A4 genomic variation. We also conducted the first extensive geographic survey of alleles associated with adult expression of CYP3A7 - that is, CYP3A7*1B and CYP3A7*1C. RESULTS AND CONCLUSION: Ethiopia contained 60 CYP3A4 variants (26 novel) and more variants (>1%) than all non-African populations combined. No nonsynonymous mutation was found in the homozygous form or at more than 2.8% in any population. Seventy-nine per cent of haplotypes contained 3'UTR and/or regulatory region variation with striking pairwise population differentiation, highlighting the potential for interethnic variation in CYP3A4 expression. Conversely, coding region variation showed that significant interethnic variation is unlikely at the protein level. CYP3A7*1C was found at up to 17.5% in North African populations and in significant linkage disequilibrium with CYP3A5*3, indicating that adult expression of the foetal isoform is likely to be accompanied by reduced or null expression of CYP3A5
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