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Search Results: 1 - 10 of 130510 matches for " Rattan V "
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Aneurysmal bone cyst of the coronoid process of the mandible
Rattan V,Goyal S
Journal of the Indian Society of Pedodontics and Preventive Dentistry , 2006,
Abstract: A rare case of aneurysmal bone cyst (ABC) located in the coronoid process of the mandible in a 12-year-old girl is presented. Treatment consisted of excision of the lesion through preauricular, submandibular and intraoral approach. An access osteotomy distal to second molar region was required to gain access to medial side of the coronoid process. To our knowledge, this is the third case of an aneurysmal bone cyst of the coronoid process of mandible. While examining a patient with a large expansile intrabony jaw cavity with thin peripheral bone, which is filled with blood without presence of bruit, thrills and pulse pressure, the diagnosis of aneurysmal bone cyst should be on top of the differential diagnosis list. Seventy-four to eighty-five percent of aneurysmal bone cysts of jaws occur in 10-20 years age group. Therefore, a pediatric dentist may be the first person to see such a lesion.
Thermo Physical Properties for Binary Mixture of Dimethylsulfoxide and Isopropylbenzene at Various Temperatures
Maninder Kumar,V. K. Rattan
Journal of Thermodynamics , 2013, DOI: 10.1155/2013/353841
Abstract: Density, refractive index, speed of sound, and viscosity have been measured of binary mixture dimethylsulfoxide (DMSO) + isopropylbenzene (CUMENE) over the whole composition range at 298.15, 303.15, 308.15, and 313.15?K and atmospheric pressure. From these experimental measurements the excess molar volume, deviations in viscosity, molar refractivity, speed of sound, and isentropic compressibility have been calculated. These deviations have been correlated by a polynomial Redlich-Kister equation to derive the coefficients and standard error. The viscosities have furthermore been correlated with two or three parameter models, that is, herric correlation and McAllister model, respectively. 1. Introduction This paper contributes in part to our ongoing research on the solution properties. In the present study, data on density, viscosity, refractive index and speed of sound of binary mixture dimethylsulfoxide (DMSO) + isopropylbenzene at 298.15, 303.15, 308.15, and 313.15?K have been measured experimentally. From these results the excess molar volumes, viscosity deviations, and deviations in molar refraction and isentropic compressibility have been derived. Dimethylsulfoxide is a versatile nonaqueous dipolar aprotic solvent having wide range of applications. It is used as a solvent in many nucleophilic substitutions reactions. It has the ability to pass through membranes, an ability that has been verified by numerous subsequent researchers. It can penetrate through living tissues without damaging them. Therefore local anesthetic or penicillin can be carried through the skin without using a needle which makes it a paramount in medicinal field. Isopropylbenzene is a naturally occurring substance present in coal tar and petroleum, insoluble in water, but is soluble in many organic solvents. It is used as a feedback for the production of Phenol and its coproduct acetone. It is also used as a solvent for fats and raisins. The study of the thermodynamic properties of DMSO + isopropylbenzene mixtures is of interest in industrial fields where solvent mixtures could be used as selective solvents for numerous reactions. 2. Experimental Section 2.1. Materials The chemicals used are of AR grade, dimethylsulfoxide (DMSO) and isopropylbenzene (CUMENE) are from Riedel, Germany. The chemicals are purified using standard procedure [1] and are stored over molecular sieves. The purity of the chemicals was verified by comparing viscosity, density, and refractive index with the known values reported in the literature as shown in Table 1. All the compositions are prepared by using
On the Complexity of Noncommutative Polynomial Factorization
V. Arvind,Pushkar S Joglekar,Gaurav Rattan
Computer Science , 2015,
Abstract: In this paper we study the complexity of factorization of polynomials in the free noncommutative ring $\mathbb{F}\langle x_1,x_2,\dots,x_n\rangle$ of polynomials over the field $\mathbb{F}$ and noncommuting variables $x_1,x_2,\ldots,x_n$. Our main results are the following. Although $\mathbb{F}\langle x_1,x_2,\dots,x_n \rangle$ is not a unique factorization ring, we note that variable-disjoint factorization in $\mathbb{F}\langle x_1,x_2,\dots,x_n \rangle$ has the uniqueness property. Furthermore, we prove that computing the variable-disjoint factorization is polynomial-time equivalent to Polynomial Identity Testing (both when the input polynomial is given by an arithmetic circuit or an algebraic branching program). We also show that variable-disjoint factorization in the black-box setting can be efficiently computed (where the factors computed will be also given by black-boxes, analogous to the work [KT91] in the commutative setting). As a consequence of the previous result we show that homogeneous noncommutative polynomials and multilinear noncommutative polynomials have unique factorizations in the usual sense, which can be efficiently computed. Finally, we discuss a polynomial decomposition problem in $\mathbb{F}\langle x_1,x_2,\dots,x_n\rangle$ which is a natural generalization of homogeneous polynomial factorization and prove some complexity bounds for it.
Primary retroperitoneal teratomas in children: A single institution experience
Rattan K,Kadian Y,Nair V,Kaushal V
African Journal of Paediatric Surgery , 2010,
Abstract: Objective: This study aims to highlight the clinical features, investigations and treatment outcome of retroperitoneal teratomas (RPT) in children. Materials and Methods: A total of eight patients (six males and two females, age range between 6 months 10 years) of RPT admitted in the department of Paediatric Surgery, PGIMS, Rohtak, between 1996 2008, were studied. The patients were investigated with hematology, x-ray, ultrasound, and computerised tomography (CT) of abdomen and serum alpha-fetoprotein levels in pre and postoperative period. All patients underwent complete surgical resection. In one patient, the tumour had malignant component (yolk sac) and was given postoperative chemotherapy. Postoperative follow-up included serum alpha-fetoprotein in addition to clinical examination and radiological assessment to detect recurrences. Results: The tumours were located on both sides in almost equal proportion (four on right, three on left, and one bilateral]. All tumours could be excised completely preserving the kidneys in all patients. But in one patient injury to inferior vena cava (IVC) occurred which was repaired successfully. Majority (7 out of 8) were histological benign, and in one yolk sac tumour was malignant component which needed chemotherapy. All children were on follow-up and one patient with malignancy lost to follow-up after three cycles of chemotherapy. In rest there was no tumour recurrence. Conclusion: RPT are rare paediatric neoplasms. As majority are benign, a complete excision preserving the kidneys, is usually curative. Serum alpha-fetoprotein is a reliable method of assessing recurrence. Malignancy in the tumour may warrant further chemotherapy.
Graph Isomorphism, Color Refinement, and Compactness
V. Arvind,Johannes K?bler,Gaurav Rattan,Oleg Verbitsky
Computer Science , 2015,
Abstract: Color refinement is a classical technique used to show that two given graphs G and H are non-isomorphic; it is very efficient, although it does not succeed on all graphs. We call a graph G amenable to color refinement if it succeeds in distinguishing G from any non-isomorphic graph H. Tinhofer (1991) explored a linear programming approach to Graph Isomorphism and defined compact graphs: A graph is compact if its fractional automorphisms polytope is integral. Tinhofer noted that isomorphism testing for compact graphs can be done quite efficiently by linear programming. However, the problem of characterizing and recognizing compact graphs in polynomial time remains an open question. Our results are summarized below: - We show that amenable graphs are recognizable in time O((n + m)logn), where n and m denote the number of vertices and the number of edges in the input graph. - We show that all amenable graphs are compact. - We study related combinatorial and algebraic graph properties introduced by Tinhofer and Godsil. The corresponding classes of graphs form a hierarchy and we prove that recognizing each of these graph classes is P-hard. In particular, this gives a first complexity lower bound for recognizing compact graphs.
Intellect and Concept
Gurpreet Rattan
The Baltic International Yearbook of Cognition, Logic and Communication , 2010, DOI: 10.4148/biyclc.v5i0.288
Abstract: The connections between theories of concepts and issues of knowledge and epistemic normativity are complex and controversial. According to the general, broadly Fregean, view that stands in the background of this paper, these connections are taken not only to exist, but also to be fundamental to issues about the individuation of concepts. This kind of view fleshed out should clarify the nature and role of epistemic norms, and of different kinds of epistemic norms, in concept individuation. This paper takes up an aspect of this general task and tries to make explicit the nature and role of intellectual norms, and to argue that extant paradigms for theorizing concepts fail because they fail to recognize the nature and individuative relevance of intellectual norms.
Stanley's character polynomials and coloured factorizations in the symmetric group
Amarpreet Rattan
Mathematics , 2006,
Abstract: Stanley introduces polynomials which help evaluate symmetric group characters and conjectures that the coefficients of the polynomials are positive. Stanley later gives a conjectured combinatorial interpretation for the coefficients of the polynomials. Here, we prove the conjecture for the terms of highest degree.
Positivity results for Stanley's character polynomials
Amarpreet Rattan
Mathematics , 2006,
Abstract: Stanley introduced expressions for the normalized characters of the symmetric group and stated some positivity conjectures for these expressions. Here, we give an affirmative partial answer to Stanley's positivity conjectures about the expressions using results on Kerov polynomials. In particular, we use new positivity results by Goulden and the present author. We shall see that the generating series $C(t)$ introduced by them is critical to our discussion.
The Posterior Epidural Ligaments: A Cadaveric and Histological Investigation in the Lumbar Region
M. J. Connor,S. Nawaz,V. Prasad,S. Mahir,R. Rattan,J. Bernard,P. J. Adds
ISRN Anatomy , 2013, DOI: 10.5402/2013/424058
Abstract: Purpose. Incidental durotomy is a relatively common complication for patients undergoing posterior spinal surgery. Delineating anatomical variants in the posterior lumbar spinal canal is crucial in reducing future rates of incidental durotomy. Materials and Methods. The ligamentous attachments between the dura mater and ligamentum flavum in the lumbar region of 17 soft-fixed cadavers were investigated. The lumbar vertebral columns were removed, and cross-sectional dissection was performed at levels L1-S1. Anterior retraction of the dorsal dura mater identified attachments between the dorsal surface of the dura mater and the ligamentum flavum. Histological staining of the ligamentous attachments was carried out with hematoxylin and eosin (H&E) and elastic van Gieson (EVG). Results. Posterior epidural ligaments were present in 9 (52.9%) cadavers. Nine (9) separate ligaments were identified in these cadavers, with 3 (33.3%) at L3/L4, 5 (55.5%) at L4/L5, and 1 (11.1%) at L5/S1. Histology confirmed the presence of poorly differentiated collagen-based connective tissue, distinct from the normal anatomy. Conclusions. This study confirms the presence of multiple dorsomedial posterior epidural ligaments at the main sites for posterior spinal surgery (L3-S1). An intraoperative awareness of the variability of such connections may be an important step in reducing static rates of incidental durotomy. 1. Introduction Low back pain is a highly prevalent complaint, reported to affect 26.4% of US adults at some point in the last three months [1], although fewer than 1% of patients proceed to undergo surgical intervention [2]. In spite of methodical advances in surgical techniques, incidental durotomy (iatrogenic dural tears) during posterior spinal surgery still occurs. Incidental durotomy or iatrogenic dural tears remain a relatively commonplace and potentially serious complication of lumbar spine surgery [3–5]. Delineating anatomical variants in the posterior lumbar spine may be crucial in reducing future rates of incidental durotomy. The aim of this study was to investigate variations in the anatomical and histological features of the posterior epidural ligaments, passing between the dura mater and the ligamentum flavum in the lumbar spine. 2. Materials and Methods Seventeen lumbar spines were dissected from randomly selected soft-fixed cadavers with no known history of spinal disease or spinal surgery. Cross-sectional anatomical dissection at the levels L1-S1 via a dorsal approach was performed. Anterior retraction of the dura mater identified any connection between
Land Management Effects on Carbon Sequestration and Soil Properties in Reclaimed Farmland of Eastern Ohio, USA  [PDF]
David A. N. Ussiri, Rattan Lal
Open Journal of Soil Science (OJSS) , 2013, DOI: 10.4236/ojss.2013.31006
Abstract:

Reclaimed mined soils (RMSs) could restore soil quality and ecosystem productivity while sequestering C and off-setting some of C emissions associated with coal utilization. The study was conducted to evaluate the effects of tillage and pasture management on soil physical properties, soil organic carbon (SOC) and microbial biomass carbon (MBC) in RMSs managed for agricultural use in eastern Ohio. Soil bulk density (ρb) of the top 50 cm ranged from 1.11 to 1.93 Mg·m-3. The ρb of the RMSs was significantly more than that of the undisturbed soils. Water stable aggregates (WSA) and mean weight diameter (MWD) of the 0 - 10 cm soil layer were significantly lower under reclaimed conventional tillage (RCT) than reclaimed no tillage (RNT) and reclaimed pasture (RP), probably due to tillage-induced disturbance. The SOC pool of the top 50 cm layer was 64.2, 66.5, 75.4, 86.1 and 101.1 Mg·C·ha-1 for undisturbed pasture (Und P), RNT, RCT, RP and undisturbed hardwood forest (Und HWF), respectively (LSD = 7.7 Mg·ha-1). The RMSs under pasture accumulated SOC at higher rates than RMSs under cropland. Reclaimed pasture land use increased SOC pool by 14% or 0.5 Mg·ha-1·yr-1 and 30% or 0.9 Mg·ha-1·yr-1 relative to RNT and RCT land uses, respectively. Our data indicated that RMSs under forest and pastures had higher SOC sequestration rates than RMSs under arable land use, probably due to disturbances associated with farm operations. The MBC of the RMSs were generally lower than those of the undisturbed sites. The disturbances associated with mining and reclamation reduced the MBC by 39, 53 and 21% under RCT, RNT and RP compared to the undisturbed forest and pasture sites. However, the amount of mineralizable C was not significantly different among land disturbances or land uses.

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