50 research outputs found
New exact treatment of the perturbed Coulomb interactions
A novel method for the exact solvability of quantum systems is discussed and
used to obtain closed analytical expressions in arbitrary dimensions for the
exact solutions of the hydrogenic atom in the external potential , which is based on the recently introduced supersymmetric
perturbation theory.Comment: 6 pages article in LaTEX (uses standard article.sty). No Figures.
Please check "http://www1.gantep.edu.tr/~ozer/" for other studies of Nuclear
Physics Group at University of Gaziante
Exact solutions of effective-mass Schrodinger equations
We outline a general method for obtaining exact solutions of Schr\"{o}dinger
equations with a position dependent effective mass and compare the results with
those obtained within the frame of supersymmetric quantum theory. We observe
that the distinct effective mass Hamiltonians proposed in the literature in
fact describe exactly equivalent systems having identical spectra and wave
functions as far as exact solvability is concerned. This observation clarifies
the Hamiltonian dependence of the band-offset ratio for quantum wells.Comment: 16 pages article in LaTEX (uses standard article.sty). Please check
http://www1.gantep.edu.tr/~ozer/ for other studies of Nuclear Physics Group
at University of Gaziantep. To appear in Modern Physics Letters
Supersymmetric approach to exactly solvable systems with position-dependent effective masses
We discuss the relationship between exact solvability of the Schr\"{o}dinger
equation with a position-dependent mass and the ordering ambiguity in the
Hamiltonian operator within the frame of supersymmetric quantum mechanics. The
one-dimensional Schr\"{o}dinger equation, derived from the general form of the
effective mass Hamiltonian, is solved exactly for a system with exponentially
changing mass in the presence of a potential with similar behaviour, and the
corresponding supersymmetric partner Hamiltonians are related to the
effective-mass Hamiltonians proposed in the literature.Comment: 12 pages article in LaTEX (uses standard article.sty). Please check
http://www1.gantep.edu.tr/~ozer for other studies of Nuclear Physics Group at
University of Gaziantep. [arXiv admin note: excessive overlap with
quant-ph/0306065 and "Supersymmetric approach to quantum systems with
position-dependent effective mass" by A. R. Plastino, A. Rigo, M. Casas, F.
Garcias, and A. Plastino - Phys. Rev. A 60, 4318 - 4325 (1999)
Coğrafi veri seçim işlemi sonuçlarının değerlendirilmesinde hata matrisinin kullanımı
Nowadays, as being in the information age, the needs for Geographic Information Systems (GIS) and for its main component geographic data are incrementally increasing. Geographic data is the most expensive and time consuming component of GIS (Longley et al., 2001). Therefore construction of automation processes in geographic data production has high importance for data providers. In case of the availability of data having higher spatial resolution, derived geographic data with certain contents and specifications can be produced through generalization. Generalization is important to GIS, not only because of to drive towards automating the process to obtain derived databases, but also because generalization can seriously affect data within a GIS, even more so than within paper maps (Joao, 1998). A fully automated generalization cannot be anticipated at this moment (Spiess et al., 2005). Still lots of efforts are needed to automate the generalization processes (Stoter, 2005). And new automated methods need new quality control methods (Jaakola, 1994; Ruas, 2001). In this study, the usage of error (confusion) matrix is investigated in the accuracy assessment of selection process aiming to obtain derived geographic data. Geographic data selection process constitutes an important step in the production of derived datasets through generalization. The results of the selection process build the main skeleton of the derived data. Selection process and criteria used are highly depended on the intended usage purpose of the generalized data. In the selection process, unwanted features are eliminated and important features are retained. It is the one of the most immediate differences between maps of the same region at different scales (Joao, 1998). Contextual relations among geographic features should be considered in the selection process. Although selection process of geographic features constitutes an important step in the production of derived datasets, it is not only enough by itself. It should be considered together with other generalization operators (Shea and McMaster, 1989) in map or geographic data production line. Error matrix is generally used in the accuracy assessments of supervised and unsupervised classification of raster data (Congalton ve Green, 1999). An error matrix is a square array of numbers set out in rows and columns which expresses the number of sample units assigned to a particular class relative to actual class as verified by some reference data (Figure 3). The selection processes in the production of derived geographic data can be assessed as a kind of classification. Geographic data is classified in two different categories as “selected” or “eliminated”. The usage of error matrix in the accuracy assessment of selection results has been realized with an application. In the application, the automatic selection result of running waters and canals for the production of derived topographic maps has been used. Geographic data covered by Balıkesir J19 topographic map sheet was chosen as a test data. 1:25.000 scale content data was used for the automatic selection of running waters and canals for the production of 1:100.000 scale Balıkesir J19 topographic map sheet. Last edition of 1:100.000 scale Balıkesir J19 map sheet has been used as a reference data that is needed for verifying the selection result and constructing the error matrix. Due to the subjectivity of generalization, extra comments have been made in defining the accuracy of the selection results of individual features, in case of conflicts occurred between the selection results and the reference data. The lengths of geographic features can also be used in constructing error matrix. In this study, two types of error matrixes were constructed, using feature numbers and feature lengths, respectively. Then the accuracies of classification as a whole and as individual categories have been computed by using the error matrixes constructed. As a result, it has been found that error matrix provides objective and thorough information for the accuracy assessment of the selection process results for obtaining derived geographic data. It can be used for this purpose. Selection criteria would directly affect the selection results. Determining optimum criteria that will be used in the production lines constitute a critical issue. The Kappa coefficient of agreement (Cohen, 1960), which takes into account all the elements of the error matrix, yields a robust assessment for the accuracy of whole classification process and can be used in determining the optimum selection criteria. Keywords: Geographic features, selection process, accuracy assessment, error matrix.Bilgi sistemlerinin yoğun olarak kullanıldığı günümüzde, Coğrafi Bilgi Sistemlerine (CBS) ve CBS’nin temel bileşenlerinden coğrafi verilere olan ihtiyaç, artarak devam etmektedir. Coğrafi verilerin üretimi, CBS bileşenleri arasında en çok zaman ve maliyet gerektiren işlemi oluşturmaktadır. Dolayısıyla coğrafi veri üreticileri için, üretim süreçlerinin otomasyonu son derece önem taşımaktadır. İstenilen nitelik ve içerikteki coğrafi veriler, daha yüksek mekânsal çözünürlüğe sahip coğrafi verilerin bulunması durumunda bu verilerden türetme yolu ile üretilebilir. Türetilen coğrafi verilerin doğruluğu, CBS içindeki veriyi ve dolayısıyla analiz sonuçlarını doğrudan etkilediğinden, basılı haritalardaki durumlarından daha da önemli hale gelmektedir. Bilgisayar destekli harita üretim tekniklerin kullanımı ile birlikte, genelleştirme işlemleri sonuçlarının değerlendirilmesinde kullanılacak yeni yöntemlere olan gereksinim, kendini belirgin olarak göstermektedir. Hata matrisi, raster verilerle yapılan sınıflandırma işlemlerinin doğruluk analizlerinde yoğun olarak kullanılmaktadır. Bu çalışmada; hata matrisinin, türetme coğrafi veri üretim amaçlı gerçekleştirilen coğrafi veri seçim işlemi sonuçlarının değerlendirmesinde kullanımı irdelenmiştir. Türetme coğrafi verilerin üretiminde gerçekleştirilen coğrafi veri seçimi, aslında bir tür sınıflandırma işlemidir. Coğrafi detaylar, “seçilen” ve “seçilmeyen” şeklinde iki ayrı sınıfa ayrıştırılmaktadır. Hata matrisinin, coğrafi veri otomatik seçim sonuçlarının değerlendirilmesinde kullanımı bir uygulama ile gerçekleştirilmiştir. Hata matrisinin, yapılan seçim işlemi sonucu ve doğruluğu hakkında yansız ve kapsamlı bir değerlendirme sunduğu ve bu amaçla kullanılabileceği görülmüştür. Hata matrisinin, seçim işlemini doğrudan etkileyen en iyi seçim ölçütlerinin belirlenmesinde de kullanılabileceği değerlendirilmektedir. Anahtar Kelimeler: Coğrafi veri, seçme ve eleme, doğruluk, hata matrisi
Pituitary macroadenomas (>3cm) in young adulthood: Pathologic and proliferative characteristics
Background
There are scarce data regarding the significance of the tumor size, hormonal activity and size of the pituitary tumor of the young; therefore, the study was designed to define the relation of the hormonal status of the large pituitary adenomas.
Objective
We compared those features with tumors of the elderly (>40) with the young patients, and analyzed the clinicopathologic and proliferative features of pituitary macroadenomas in young adulthood (≤40).
Methods
20-year archives of pituitary tumors in our clinics were reviewed and macroadenomas with diameter ≥3cm were included in the study. We identified 46 pituitary adenomas and immunohistochemically stained them with pituitary hormones, p53 and Ki-67. Twenty-four cases were ≤40-year with an age range of 11–40 years (mean 28.0). Twenty-two cases were >40 with an age range of 44–78 years (mean 58.8).
Results
In the young patient group, 15 (62.5%) were functional adenomas (6 prolactinomas, six growth hormone [GH], one adrenocorticotrophic hormone [ACTH] adenoma, two multihormonal [GH+ACTH]) and nine (37.5%) were either gonadotrophic or null cell adenomas. In the elderly group, five (22.7%) were functional adenomas (two adrenocorticotrophic hormone [ACTH] adenoma, one prolactinoma, one growth hormone [GH], one multihormonal [GH+ACTH]) and 17 (77.3%) were either gonadotrophic or null cell adenomas. Ki-67 proliferation index in adenomas of the young was approximately two-folds higher than the elderly (2.7% vs. 1.2%).
Conclusion
In both groups, rare p53 positivity was identified. In conclusion, pituitary macroadenomas of the young show hormonal expression frequently with relatively high Ki-67 proliferation indices
Two Electrons in a Quantum Dot: A Unified Approach
Low-lying energy levels of two interacting electrons confined in a
two-dimensional parabolic quantum dot in the presence of an external magnetic
field have been revised within the frame of a novel model. The present
formalism, which gives closed algebraic solutions for the specific values of
magnetic field and spatial confinement length, enables us to see explicitly
individual effects of the electron correlation.Comment: 14 page
A note on the Woods-Saxon potential
The wave Schrodinger and, to clarify one interesting point encountered in the
calculations, Klein-Gordon equations are solved exactly for a single neutron
moving in a central Woods-Saxon plus an additional potential that provides a
flexibility to construct the surface structure of the related nucleus. The
physics behind the solutions and the reliability of the results obtained are
discussed carefully with the consideration of other related works in the
literature. In addition, the exhaustive analysis of the results reveals the
fact that the usual Woods-Saxon potential cannot be solved analytically within
the framework of non-relativistic physics, unlike its exactly solvable
relativistic consideration
Efficiency of Fluid Treatments with Different Sodium Concentration in Children with Type 1 Diabetic Ketoacidosis
Objective: The management of children with diabetic ketoacidosis (DKA) continues to be a controversial issue with regard to amount of intravenous fluid to be given, rate of delivery of fluid, and type of fluid to be used. We aimed to analyze the results obtained by administration of rehydration fluids of two different sodium (Na) concentrations (75 mEq/L vs. 100 mEq/L ) in the treatment of children with DKA
Case Report: Two Patients with Partial DiGeorge Syndrome Presenting with Attention Disorder and Learning Difficulties
DiGeorge syndrome (DGS) has classically been characterized by the triad of clinical features including congenital cardiac defects, immune deficiencies secondary to aplasia or hypoplasia of the thymus, and hypocalcaemia due to small or absent parathyroid glands. The phenotypic features of these patients are much more variable and extensive than previously ecognized. The acknowledgement of similarities and phenotypic overlap of DGS with other disorders associated with genetic defects in 22q11 has led to an expanded description of the phenotypic features of DGS including palatal/speech abnormalities, as well as cognitive, neurological and psychiatric disorders. Here, we report the cases of two DGS patients with dysmorphic facial features who were initially admitted to the Psychiatry Department for attention disorder and learning difficulties