3,382 research outputs found

    Halo Structure Of C-19 Via The (p,d) Reaction

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    We have investigated the heaviest one-neutron halo candidate C-19 nucleus. Few-body model calculations of cross section angular distributions for the C-19(p,d)C-18 reaction, together with the test calculations carried out for the C-17(p,d)C-16 reaction, at a low incident energy are presented for different possible halo-neutron configurations. We show that there is a clear distinction between in particular â„“n=0\ell_{n}=0 and â„“n=2\ell_{n}=2 halo transfers. The sensitivity of the cross sections to the assumed C-19 single neutron separation energy is discussed.Comment: LaTEX (uses article.sty), 11 pages and 4 figures (in PS format). Please check http://physics.gantep.edu.tr/~nuclear/publications.html for other other studies of Nuclear Physics Group at University of Gaziantep. To be published in Few Body Systems Journal in May 200

    Significance Of Deuteron Breakup In A Halo Transfer Reaction

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    We discuss the quasi-adiabatic approximations to the three-body wavefunction in breakup processes, clarifying the assumptions underlying the model. This suggests alternative approximation schemes. Using different theoretical three-body models, calculated differential cross section angular distributions for the Be-11(p,d) reaction,for which new preliminary data have been reported at 35 MeV, are presented. We show that calculations are sensitive to the inclusion of deuteron breakup and to the breakup model used, particularly if used to deduce absolute spectroscopic information on the 0{+} and 2{+} Be-10 core state parentages. There is also considerable sensitivity to the model used in calculations of the relative cross sections to the two states.Comment: LaTEX (uses article.sty), 16 pages and 3 figures (EPS format). Please check http://physics.gantep.edu.tr/~nuclear/publications.html for other other studies of Nuclear Physics Group at University of Gaziante

    Probabilistic facial feature extraction using joint distribution of location and texture information

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    In this work, we propose a method which can extract critical points on a face using both location and texture information. This new approach can automatically learn feature information from training data. It finds the best facial feature locations by maximizing the joint distribution of location and texture parameters. We first introduce an independence assumption. Then, we improve upon this model by assuming dependence of location parameters but independence of texture parameters.We model combined location parameters with a multivariate Gaussian for computational reasons. The texture parameters are modeled with a Gaussian mixture model. It is shown that the new method outperforms active appearance models for the same experimental setup

    Investigation of phase-equivalent potentials by a halo transfer reaction

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    Using the supersymmetric quantum mechanics we investigate the wave function-sensitive properties of the supersymmetric potentials which have received a lot of attention in the literature recently. We show that a superdeep potential and its phase-equivalent shallow-partner potential give very similar "rms" values for the weakly bound systems such as the deuteron and 11Be nuclei. Although the corresponding eigenstates differ in the node-number, our investigation on the 11Be(p,d)10Be single nucleon halo transfer reaction at 35 MeV show that also other physical quantities such as the cross section angular distributions calculated using these wave functions reflect the nodal structure rather weakly. This lends support to two nearly equivalent treatments of the Pauli principle.Comment: 20 pages article in LaTEX (uses standard article.sty). Figures can be obtained from author(s). Please check "http://www1.gantep.edu.tr/~ozer" for other studies of Nuclear Physics Group at University of Gaziante

    The Market Performance of Initial Public Offerings in the Istanbul Stock Exchange

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    This study examines the long-standing IPO performance in the Istanbul Stock Exchange (ISE) by using new factors such as source of shares (new issue or sale of large shareholders), allocation of shares and dispersion of investors as well as existing factors such as market conditions (hot/cold), underwriters’ reputation, and firm characteristics (firm size, E/P, and B/M ratios) in the period of 1990-2000. Our results differ from the previous studies at least three ways. First, the magnitude of underpricing is significantly lower, while underperformance is higher than those of in other studies. Our strong evidence supports the existence of the underpricing by positive initial excess returns (5.94%) and the long-term underperformance up to three-year holding period (-84.5%) in the ISE. Second, underperformance starts much earlier than in other markets i.e. at the end of first month following the IPO because of myopic behavior of investors seeking short-term returns. Third, the underperformance disappears for IPOs made in a cold market, and those made through the sale of large shareholders. Allocation of shares in an IPO and firm size also impact after-market performance of sharesInitial Public Offerings, Underperformance, Underpricing, Market Efficiency, Emerging Markets

    Is there a Future for the Isolated Oriental Beech (Fagus orientalis Lipsky) Forests in Southern Turkey?

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    Oriental beech (Fagus orientalis Lipsky) is mainly found in the northern region of Turkey.There is also an approximate 40,000 ha of isolated relict oriental beech forest in southern Turkey. Thisrelict population differs somewhat from the northern distribution in terms of average altitudinaldistribution, health conditions, and reactions to climate change. Beech forest distribution in southernTurkey starts at about 1000 m, contrary to the northern distribution, which begins at about 150-200 m. Insouthern Turkey, the average temperature is higher, and summer drought occurs due to irregular rainfall.Beech trees in the south decay at earlier ages due to their sprout origins and higher temperatures than in thenorth. In recent decades, some part of the beech forests have shed leaves during the summer in response tosevere drought. Therefore, these relict populations are on the verge of extinction under unfavorableconditions

    ARTIFICIAL NEURAL NETWORKS PRUNING APPROACH FOR GEODETIC VELOCITY FIELD DETERMINATION

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    There has been a need for geodetic network densification since the early days oftraditional surveying. In order to densify geodetic networks in a way that willproduce the most effective reference frame improvements, the crustal velocity fieldmust be modelled. Artificial Neural Networks (ANNs) are widely used as functionapproximators in diverse fields of geoinformatics including velocity fielddetermination. Deciding the number of hidden neurons required for theimplementation of an arbitrary function is one of the major problems of ANN thatstill deserves further exploration. Generally, the number of hidden neurons isdecided on the basis of experience. This paper attempts to quantify the significanceof pruning away hidden neurons in ANN architecture for velocity fielddetermination. An initial back propagation artificial neural network (BPANN) with30 hidden neurons is educated by training data and resultant BPANN is applied ontest and validation data. The number of hidden neurons is subsequently decreased,in pairs from 30 to 2, to achieve the best predicting model. These pruned BPANNsare retrained and applied on the test and validation data. Some existing methods forselecting the number of hidden neurons are also used. The results are evaluated interms of the root mean square error (RMSE) over a study area for optimizing thenumber of hidden neurons in estimating densification point velocity by BPANN

    EQUALITY - NOW OR NEVER: THE POLITICAL THOUGHT OF ENVER HOXHA

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    Students of politics know very well that Plato's perfect city in Republic is a political model of philosophico-pedagogical tyranny. For Ranciere, the political thought ofthe thinker of autocratic hierarchy, namely Plato, has much to do with what Ranciere calls the founding gesture of philosophy. In other words, since Plato, asilent majority has always been excluded from the privilege of thought and art and this has helped the construction of the implicit alliance between philosophy and there pressive order of social hierarchy. According to Ranciere, Marx, Sartre,Althusser and Bourdieu, despite their intellectual standing in the Left, are thinkers of inequality and pedagogical privilege. Each assumes, as Plato does, that the pedagogue must think for and educate those who are unable to think for themselves;only then will society change for the better. Yet, the fundamental gesture of philosophy (and even science) not only provides privileges to intellectuals but also continuously postpones the actual realization of achieving equality. If we take equality as an end rather than a presupposition or an axiomatic point of departureit would only prolong the hierarchy between "those who know" and "those who does not know". In this paper, I plan to examine Enver Hoxha's political thought from a Rancierean perspective. I mainly focus on a major concept which unifies Ranciereian thought, that being "equality"

    Lip segmentation using adaptive color space training

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    In audio-visual speech recognition (AVSR), it is beneficial to use lip boundary information in addition to texture-dependent features. In this paper, we propose an automatic lip segmentation method that can be used in AVSR systems. The algorithm consists of the following steps: face detection, lip corners extraction, adaptive color space training for lip and non-lip regions using Gaussian mixture models (GMMs), and curve evolution using level-set formulation based on region and image gradients fields. Region-based fields are obtained using adapted GMM likelihoods. We have tested the proposed algorithm on a database (SU-TAV) of 100 facial images and obtained objective performance results by comparing automatic lip segmentations with hand-marked ground truth segmentations. Experimental results are promising and much work has to be done to improve the robustness of the proposed method

    Dormantnost sjemena i morfologija bobuljastih češera i sjemena koštuničave borovice (Juniperus drupacea Labill.) u istočno mediteranskom području Turske

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    Syrian juniper, Juniperus drupacea Labill., is an Eastern Mediterranean tree species which belongs to the Cupressaceae family and Juniperoidae sub-family. The current geographical range of J. drupacea covers the southern parts of the Peloponnese in Greece, the southern parts of Asia Minor and the mountains of Syria and Lebanon. The main part of the species range in Turkey is divided into several centres the most important being located in the Taurus, Anti-Taurus and Amanos mountains. It is a dioecious tree, with conical crown, that reaches 10-20 (40) m in height. The fleshy cones are ovoid to globose, 20-25 mm in diameter, brownish-purple or bluish-black, glaucosus and pruniose when ripe in the second year. They mostly have 3 seeds forming a characteristic drupe-like stone. The natural regeneration of Syrian juniper is very difficult because of animal consumption, grazing and the united seeds into the woody structure. This study was carried out to determine the seed and cone morphology and seed physiology of Syrian juniper, Juniperus drupacea Labill., from three provenances (Kahramanmaraş, Mersin, Adana) in the Eastern Mediterranean region of Turkey. In total 11 morphological traits were measured. The average cone length, cone diameter, and cone weight were 22.49 mm, 20.86 mm and 4.659 g, respectively. The average seed length, width, thickness, weight and pulp weight were 10.07 mm, 3.30 mm, 2.77 mm 0.045 g and 2.220 g in order. After morphological analysis, a series of experiments was conducted to identify the best stratification treatment for breaking dormancy in Syrian juniper seeds. The highest germination percentage was obtained after warm and cold stratification (80.7%). The seeds prechilled 8 weeks and soaked 500 ppm GA3 also demonstrated high germination percentage. The current study demonstrated that J. drupacea seeds has morphophysiological dormancy.Sirijska smreka, Juniperus drupacea Labill. je istočno mediteranska vrsta stabla koja pripada porodici Cupressaceae, roduJuniperoidae. J. drupacea trenutno pokriva geografsko područje južnog dijela Peloponeza u Grčkoj, južne dijelove Male Azije te sirijske i libanonske planine. Glavni dio područja te vrste u Turskoj podijeljen je na nekoliko središta, od kojih je najvažniji smješten u Taurskom gorju, Anti-Taurus gorju te planinama Amanos. Stablo je diecično, s konusnom krošnjom koja može doseći 10-20 (40) m visine. Mesnati češeri su ovalnog do okruglog oblika, 20-25 mm u promjeru, smećkasto-ljubičaste ili plavkasto-crne boje, te žućkasti i bjelkasti kada su zreli tijekom druge godine. Uglavnom imaju 3 sjemenke koje tvore karakterističnu košticu nalik na košticu koštičavog voća. Prirodna regeneracija sirijske smreke vrlo je teška zbog konzumacije od strane životinja, ispaše i sjemenki koje su objedinjene u drvenastu strukturu. Ovo je istraživanje provedeno kako bi se odredila morfologija sjemenke i češera te fiziologija sjemenke sirijske smreke, Juniperus drupacea Labill., koja potječe iz tri provincije (Kahramanmaraş, Mersin, Adana) u istočnomediteranskoj regiji Turske. Ukupno je izmjereno 11 morfoloških obilježja. Prosječna duljina češera bila je 22,49 mm, promjer češera 20,86 mm, a težina češera 4,659 g. Prosječna duljina, širina, debljina, težina sjemenke i težina pulpe sjemenke iznosile su redom 10,07 mm, 3,30 mm, 2,77 mm, 0,045 g i 2,220 g. Nakon morfološke analize, proveden je niz eksperimenata kako bi se odredila najbolja mjera stratifikacije radi prekidanja dormantnosti sjemenki sirijske smreke. Najveći postotak klijavosti dobiven je nakon tople i hladne stratifikacije (80,7%). Sjemenke koje su se prethodno hladile 8 tjedana te su namakane u 500 ppm GA3također su pokazale velik postotak klijavosti. Ovo je istraživanje također pokazalo da sjemeJ. drupaceaposjeduje morfološku dormantnost
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