1,159 research outputs found
A Study of Crop Yield Prediction Using Machine Learning Approaches
Agriculture plays a pivotal role in our society by providing food, fiber, and raw materials for various industries. The world's population is steadily growing, and there is increasing pressure on agriculture to meet the rising global food demand. In this context, the use of machine learning approaches to predict crop yields has gained significant importance. This paper aim is to study the significance of crop yield prediction through machine learning, its methods, applications, and its potential to revolutionize the agricultural sector
Covariant hamiltonian spin dynamics in curved space-time
The dynamics of spinning particles in curved space-time is discussed,
emphasizing the hamiltonian formulation. Different choices of hamiltonians
allow for the description of different gravitating systems. We give full
results for the simplest case with minimal hamiltonian, constructing constants
of motion including spin. The analysis is illustrated by the example of motion
in Schwarzschild space-time. We also discuss a non-minimal extension of the
hamiltonian giving rise to a gravitational equivalent of the Stern-Gerlach
force. We show that this extension respects a large class of known constants of
motion for the minimal case.Comment: 14 pages, accepted version for Phys Lett B, added a footnote and two
reference
Manufacturing Technology Today
Manufacturing Technology Today, Manufacturing Technology Abstracts, Vol. 14, No. 4, September 2015, Bangalore, India
Optimization based automated curation of metabolic reconstructions
<p>Abstract</p> <p>Background</p> <p>Currently, there exists tens of different microbial and eukaryotic metabolic reconstructions (e.g., <it>Escherichia coli, Saccharomyces cerevisiae</it>, <it>Bacillus subtilis</it>) with many more under development. All of these reconstructions are inherently incomplete with some functionalities missing due to the lack of experimental and/or homology information. A key challenge in the automated generation of genome-scale reconstructions is the elucidation of these gaps and the subsequent generation of hypotheses to bridge them.</p> <p>Results</p> <p>In this work, an optimization based procedure is proposed to identify and eliminate network gaps in these reconstructions. First we identify the metabolites in the metabolic network reconstruction which cannot be produced under any uptake conditions and subsequently we identify the reactions from a customized multi-organism database that restores the connectivity of these metabolites to the parent network using four mechanisms. This connectivity restoration is hypothesized to take place through four mechanisms: a) reversing the directionality of one or more reactions in the existing model, b) adding reaction from another organism to provide functionality absent in the existing model, c) adding external transport mechanisms to allow for importation of metabolites in the existing model and d) restore flow by adding intracellular transport reactions in multi-compartment models. We demonstrate this procedure for the genome- scale reconstruction of <it>Escherichia coli </it>and also <it>Saccharomyces cerevisiae </it>wherein compartmentalization of intra-cellular reactions results in a more complex topology of the metabolic network. We determine that about 10% of metabolites in <it>E. coli </it>and 30% of metabolites in <it>S. cerevisiae </it>cannot carry any flux. Interestingly, the dominant flow restoration mechanism is directionality reversals of existing reactions in the respective models.</p> <p>Conclusion</p> <p>We have proposed systematic methods to identify and fill gaps in genome-scale metabolic reconstructions. The identified gaps can be filled both by making modifications in the existing model and by adding missing reactions by reconciling multi-organism databases of reactions with existing genome-scale models. Computational results provide a list of hypotheses to be queried further and tested experimentally.</p
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
Evaluation of Mechanical and Metallurgical Properties of Dissimilar Materials by Friction Welding
AbstractFriction welding has been widely used to metals with dissimilar materials due to solid state joining process and shows good mechanical properties. In this study, the effect of mechanical and metallurgical properties of austenitic stainless steel (304L) and copper were experimentally investigated by tensile and hardness test while the metallurgical properties of optical, scanning electron microscopy and atomic force microscopy was used to analyze the microstructure of the welded joint. The joints were also examined with EDX line in order to understand the phases formed during welding. The material is evaluated by tensile test and their strength is determined and the hardness test measurements are examined in base metal and heat affected zone. The bonded materials of austenitic stainless steel and copper joint were produced by varying the friction pressure, upset pressure and rotational speed through Taguchi's orthogonal array. The highest tensile strength obtained in friction welded joint was 2.52% higher than parent material of copper. The effects of metallurgical characterization are discussed based on the microstructural studies
Spinning bodies in curved space-time
We study the motion of neutral and charged spinning bodies in curved
space-time in the test-particle limit. We construct equations of motion using a
closed covariant Poisson-Dirac bracket formulation which allows for different
choices of the hamiltonian. We derive conditions for the existence of constants
of motion and apply the formalism to the case of spherically symmetric
space-times. We show that the periastron of a spinning body in a stable orbit
in a Schwarzschild or Reissner-Nordstr{\o}m background not only precesses, but
also varies radially. By analysing the stability conditions for circular motion
we find the innermost stable circular orbit (ISCO) as a function of spin. It
turns out that there is an absolute lower limit on the ISCOs for increasing
prograde spin. Finally we establish that the equations of motion can also be
derived from the Einstein equations using an appropriate energy-momentum tensor
for spinning particles.Comment: 26 pages, 5 figures; v2: version accepted for publication; small
changes in text and references adde
Influence of Storage Containers and Seed Pelleting on Seed Quality in Brinjal (Solanum melongena L.) during Storage
The experiment was conducted using brinjal hybrid seeds cv. Arka Navneet. Seeds were pelleted with Bavistin, ZnSO4, MnSO4, DAP and Arappu leaf powder and stored in paper and polyethylene bags under ambient conditions for 12 months. Among the seed pelleting treatments, seeds pelleted with Bavistin (0.1%) followed by Albezia amara leaf powder (250 g/kg) resulted in minimum quantitative losses with better seed quality parameters. The seeds stored in polyethylene (700 gauges) bags maintained better seed quality parameters with less quantitative losses in comparison with seeds stored in paper bags throughout the storage period. In the interaction, effect of seeds pelleted with Bavistin and stored in polyethylene bag followed by Albezia amara leaf powder and stored in polyethylene bag revealed higher values for all the positive quality parameters when compared to other interaction effects throughout the storage period
Anatomical study of Human Tricuspid Value
INTRODUCTION:
Tricuspid Valve sometimes called the “Forgotten Valve” and a “Second-Class Structure” in Cardiac Surgery. It can be a potential source of considerable morbidity and mortality , both when it is a primary site of disease and when it is secondarily involved in left heart or pulmonary vascular disease.
The Tricuspid valve complex consists of functional units which include Tricuspid annulus, valve leaflets, chordae tendineae and papillary muscles.
The tricuspid valve annulus is a collagenous ring succeeding the orifice, where the bases of the cusps are attached. The annulus is composed of anterior and posterior rims of collagenous tissue. The leaflets or cusps of tricuspid valve are three in number, named anterior, posterior and septal according to their attachment to the annulus. Anterior leaflet is the largest and septal is the smallest. The junctions between the leaflets are represented by deep indentation or commissures, which are named as the anteroseptal,
posteroseptal and anteroposterior commissures. The anterior leaflet is attached to the upper margin of the annulus and extends medially across the membranous part of the
ventricular septum to meet the septal leaflet at the anteroseptal commissure. The septal leaflet is attached horizontally to the lower margin of the annulus and extends from antero posterior to postero septal commissures.The septal leaflet extends from the muscular part to the ventricular septum.Each leaflet presents from the free margin
to the annulus 3 zones -rough, clear and basal zones.
AIM OF THE STUDY:
Normal tricuspid valve function depends upon the anatomical and mechanical integrity of the AV ring, the valve leaflets, chordate tendineae and papillary muscles. Advances in echocardiography, invasive cardiology and surgical reconstruction of Tricuspid valves necessitate an appreciation of the many variations in the anatomy of the Tricuspid valve for Interventional Cardiologists and Cardiac Surgeons.
The classical description of the tricuspid valve found in the text books of anatomy is inadequate for the need of cardiac surgeon. Similarly the importance of the valvular structures and the myocardium in the mechanism of valve closure requires a new
appraisal in view of recent observations.
Numerous variations in the configuration of the cusp tissue and chordal/papillary support of the tricuspid valve, making the interior of the right ventricle as unique to each individual as one’s finger print.
The aim of the present study is to analyse the morphological and morphometric details of the human tricuspid valve complex.
MATERIALS AND METHODS:
STUDY MATERIALS:
1. Heart from 45 adult cadavers.
2. Fetal heart from 5 dead fetus.
3. Adult 2 dimensional Echocardiogram.
METHODS OF STUDY:
A. Dissection method:
• Conventional dissection method.
B. Radiological study:
• Adult 2D Echocardiogram Study.
SPECIMEN COLLECTION:
1. Forty five adult embalmed human cadavers were selected from the cadavers allotted to the first MBBS students and first BDS students at the Institute of Anatomy, Madras Medical College, Chennai-3.
2. Five dead unclaimed fetuses were obtained from the Institute of Obstetrics and Gynaecology, Egmore. Fetal embalming was done by injecting 200 ml of embalming fluid consisting of formalin, glycerol, alcohol and thymol, through the aorta.
CONCLUSION:
The Tricuspid valve which guards right atrioventricular orifice was studied in detail by conventional dissection and radiological (echocardiogram) method. The shape and circumference of tricuspid valve annulus, number and length of commissures, number, shape, height and length of tricuspid leaflets, types of chordae tendineae, number of chordae tendineae at origin and insertion, papillary muscle and its numbers have been observed and correlated with the findings of already existing studies.
The following conclusions are derived from these parameters:-
• The shape of the Tricuspid annulus were circular in 39 heart specimens (86.7%) and oval in 6 heart specimens (13.3%).
• The circumference of the tricuspid annulus ranged from 10.3cm-13 cm and the mean circumference was found to be 11.8 cm.
• The number of commissures in 36 hearts were 3 in number namely AP ,PS and AS commissure. 9 heart specimens with accessory leaflets presented with accessory commissures.
• The average length of AP commissure was 1.17cm (range 0.9-1.4 cm) and average length of PS commissure was 0.74cm (range 0.6-0.9 cm).The average length of AS commissure was 0.64cm (range 0.5-0.9 cm).
• The number of leaflets in tricuspid valve of 36 hearts were found to be 3 in number (80%). 4 leaflets were found in 6 hearts (13.5%), 5 leaflets in one heart (2.2%) and 6 leaflets in 2 hearts (4.4%).
• The shape of the anterior , posterior leaflets were triangular in all the 45 hearts (100%). The septal leaflets were triangular in 42 hearts (93.3%) and semicircular in 3 hearts (6.7%).
• Accessory leaflets found in 9 hearts (20%) having 4 , 5 and 6 leaflets and all were triangular in shape. Two types of accessory leaflets, spurious and true accessory leaflet were identified.
• Two types of foramina were found in tricuspid valves. True natural foramina were present in 3 hearts and spurious foramina in 9 hearts.
• The height of the anterior leaflet ranged from 1.9 – 2.5 cm (mean 2.21 cm), septal leaflet 1.4-1.9cm (mean 1.68 cm) and posterior leaflet 1.7-2.2 cm (mean 1.92 cm).
• The length (width) of the anterior leaflet varied from 3.0 – 3.9 cm (mean 3.51cm), septal leaflet 2.8-3.9cm (mean 3.26 cm) and posterior leaflet 2.0-3.2 cm (mean 2.5 cm).
• The height of the accessory leaflet ranged from 0.6 – 1.4 cm (mean 0.95 cm) and length (width) of the accessory leaflet varied from 0.7 – 1.4 cm (mean 1.08 cm).
• All 5 types of chordae namely Rough Zone Chordae,
Commissural chordae, Free edge chordae, Deep and Basal chordae were present in the present study.
• The number of chordae tendineae originated from APM ranged from 3 to 10 (mean 5.7) and from SPM ranged from 0 to 8 (mean 3.71). The number of chordae tendineae originated from PPM ranged from 1 to 8 (mean 3.75 ). In 10 hearts there
were no SPM and in these 10 hearts the chordae tendineae directly arose from ventricular wall.
• The number of chordae tendineae inserted into anterior leaflet ranged from 9 to 21 (mean 14.2) and in septal leaflet the number ranged from 7 to 18 (mean 11.95).The number of chordae tendinae inserted into posterior leaflet ranged from 8 to 16 (mean 9).3to6 chordae tendinae were inserted into the commissures and clefts.
• The anterior and posterior papillary muscles were present in all the 45 hearts (100%).The septal papillary muscles presented only in 35 hearts ( 77.8%).
• The APM was presented with one head (belly) in 37 hearts, 2 heads in 7 hearts and 3 heads in 1 heart.
• The SPM were absent in 10 hearts ,presented with one head in 7 hearts , 2 heads in 14 hearts ,3 heads in 10 hearts and 4 heads appeared in 4 hearts.
• The posterior papillary muscle presented with one head in 17 hearts, 2 heads in 20 hearts, 3 heads in 8 hearts.
Based on this study, I hereby conclude that the "Anatomical study of Human Tricuspid Valve " is composed of variations in the shape, circumference of tricuspid annulus, number and length of commissures, number, shape, height and length of tricuspid valve
leaflets ,chordae tendineae and papillary muscle.
Hence I hope that this study would be of great use to the cardiologist and cardiac surgeons, in echocardiography, interventional cardiology and in surgical reconstruction of Tricuspid valves. The morphometric analysis of the valve is useful for the cardiac surgeons to determine the size of the prosthetic valves in valve replacement, annuloplasty, commissurotomy, and artificial chordae tendineae replacement
- …