Luminous X-ray AGN in Clusters of Galaxies

We present a study of X-ray AGN overdensities in 16 Abell clusters, within the redshift range 0.073<z<0.279, in order to investigate the effect of the hot inter-cluster environment on the triggering of the AGN phenomenon. The X-ray AGN overdensities, with respect to the field expectations, were estimated for sources with L_x>= 10^{42} erg s^{-1} (at the redshift of the clusters) and within an area of 1 h^{-1}_{72} Mpc radius (excluding the core). To investigate the presence or not of a true enhancement of luminous X-ray AGN in the cluster area, we also derived the corresponding optical galaxy overdensities, using a suitable range of $r$-band magnitudes. We always find the latter to be significantly higher (and only in two cases roughly equal) with respect to the corresponding X-ray overdensities. Over the whole cluster sample, the mean X-ray point-source overdensity is a factor of ~4 less than that corresponding to bright optical galaxies, a difference which is significant at a >0.995 level, as indicated by an appropriate t-student test. We conclude that the triggering of luminous X-ray AGN in rich clusters is strongly suppressed. Furthermore, searching for optical SDSS counterparts of all the X-ray sources, associated with our clusters, we found that about half appear to be background QSOs, while others are background and foreground AGN or stars. The true overdensity of X-ray point sources, associated to the clusters, is therefore even smaller than what our statistical approach revealed.Comment: accepted for publication in ApJ Letter

Kinematics of the ring-like nebula SuWt 2

We present the first detailed spatio-kinematical analysis and modelling of the Southern planetary nebula SuWt 2. This object presents a problem for current theories of planetary nebula formation and evolution, as it is not known to contain a central post-main sequence star. Deep narrowband [NII]6584 images reveal the presence of faint bipolar lobes emanating fromthe edges of the nebular ring. Longslit observations of the H-alpha and [NII]6584 emission lines were obtained using EMMI on the 3.6-m ESO-NTT. The spectra reveal the nebular morphology as a bright torus encircling the waist of an extended bipolar structure. By deprojection, the inclination of the ring is found to be 68\degr $\pm$ 2\degr (c.f. ~90\degr for the double A-type binary believed to lie at the centre of the nebula), and the ring expansion velocity is found to be 28 km/s. Our findings are discussed with relation to possible formation scenarios for SuWt 2. Through comparison of the nebular heliocentric systemic velocity, found here to be -25 $\pm$ 5 km/s, and the heliocentric systemic velocity of the double A-type binary, we conclude that neither component of the binary could have been the nebular progenitor. However, we are unable to rule out the presence of a third component to the system, which would have been the nebula progenitor.Comment: 7 pages, 4 figures. Accepted for publication in MNRA

Low-ionization pairs of knots in planetary nebulae: physical properties and excitation

We obtained optical long-slit spectra of four planetary nebulae (PNe) with low-ionization pair of knots, namely He 1-1, IC 2149, KjPn 8 and NGC 7662. These data allow us to derive the physical parameters and excitation of the pairs of knots, and those of higher ionization inner components of the nebulae, separately. Our results are as follows. 1) The electron temperatures of the knots are within the range 9500 to 14500 K, similar to the temperatures of the higher ionization rims/shells. 2) Typical knots' densities are 500 to 2000 cm^{-3}. 3) Empirical densities of the inner rims/shells are higher than those of the pairs of knots, by up to a factor of 10. Theoretical predictions, at variance with the empirical results, suggest that knots should be denser than the inner regions, by at least a factor of 10. 4) Empirical and theoretical density contrasts can be reconciled if we assume that at least 90% of the knots' gas is neutral (likely composed of dust and molecules). 5) By using Raga et al. (2008) shock modeling and diagnostic diagrams appropriated for spatially resolved PNe, we suggest that high-velocity shocked knots traveling in the photoionized outer regions of PNe can explain the emission of the pairs of knots analysed in this paper.Comment: The paper contains 11 pages (6 figures and 5 tables). Accepted for publication in MNRAS; added last paragraph for subsection 7.

A rare cause of intra-abdomınal cystic lesion: mesenterıc cystic lymphangioma

Lymphangiomas are the benign cystic masses that resulted from the proliferation of lymp-hatic vessels due to lymphatic blockage in the lymphatic system. Usually localized in the axil-la and neck and often encountered in the pe-diatric age group. Abdominal lymphangiomas in the differential diagnosis of mesenteric cysts are very rare lesions and often localized in the small bowel mesentery. It presented with dif-ferent symptoms depending on the size and location of the cyst. In the literature, less than of 200 cases of abdominal lymphangioma have been reported in all age groups. In this article, we aim to present the case of mesenteric ab-dominal cystic lymphangioma which inciden-tally detected during a routine gynecological examination.Lenfanjiomalar, lenfatik sistemdeki blokaj ile lenf damarlarının proliferasyonu sonucu ortaya çıkan benign kistik oluşumlardır. Sıklıkla boyun ve aksillada lokalize olur ve pediatrik yaş grubunda karşılaşılır. Mezenterik kist ayırıcı tanısında yer alan abdominal lenfanjiomalar ise oldukça seyrek görülen kistik lezyonlardır ve sıklıkla ince bağırsak mezenterinde yerleşir. Kistin büyüklüğü ve lokalizasyonuna göre farklı semptomlar ile presente olur. Literatürde tüm yaş gruplarında 200’den daha az sayıda abdominal lenfanjioma olgusu bildirilmiştir. Bu yazımızda, rutin jinekolojik muayene sırasında tesadüfi olarak saptanmış olan ve preoparatif değerlendirme sonrası mezenterik kistik lezyon ön tanısıyla opere edilen abdominal mezenterik kistik lenfanjioma tanılı bir olguyu sunmayı amaçladık

Lipschitzi kujutused ja M-ideaalid

Käesolevas magistritöös näidatakse üksikasjalikult, kuidas Nigel J. Kaltoni artiklis [K2, Theorem 6.6] tõestatud teoreemist järeldub positiivne lahendus Dirk Werneri and Heiko Berningeri poolt artiklis [BW] uuritud probleemile: kas väike Hölderi ruum lip([0; 1] ), kus 0 < < 1, on M-ideaal suures Hölderi ruumis Lip([0; 1] )? Magistritöös tõestatakse samuti kaks uut tulemust väikese Lipschitzi ruumi lip(M) kohta. Esiteks tõestatakse, et kui M on kompaktne meetriline ruum, siis ruumil lip(M) on omadus (M ). Teiseks näidatakse, et kui M on kompaktne meetriline ruum ja ruumil lip(M) on meetriline aproksimatsiooniomadus, siis ruumil lip(M) on omadus (M1). Kasutades neid tulemusi tõestatakse mitu olulist järeldust. Esimese teoreemi abil näidatakse muu hulgas, et kui M on kompaktne meetriline ruum ja X on selline Banachi ruum, mille korral ruum K(X) on M-ideaal ruumis L(X), siis ruum K(lip(M);X) on M-ideaal ruumis L(lip(M);X). Teise teoreemi abil saadakse, et kui M kompaktne meetriline ruum ja ruumil lip(M) on meetriline aproksimatsiooniomadus, siis ruum K(lip(M); Y ) M-ideaal ruumis L(lip(M); Y ) iga Banachi ruumi Y korral

Barjääriga optsiooni hinna määramine binoom- ja trinoommeetodi modifikatsioonidega

Optsioon annab optsiooni omanikule võimaluse alusvara osta või müüa eelnevalt kindlaksmääratud ajahetkel tulevikus fikseeritud hinnaga. Käesolevas töös vaatleme bino- trinoommeetodit ja adaptiivsete võrede meetodit (AVM) barjääriga optsiooni hinna leidmiseks. Bino- trinoommeetod on kombinatsioon binoom- ja trinoommeetodist, mille korral konstrueeritakse alusvara hinnapuu selliselt, et barjäär või barjäärid läbivad hinnapuu tippe. Adaptiivsete võrede meetodi korral konstrueeritakse lisaks tavalisele trinoompuule üks või mitu tihedamat võret nii, et barjäär läbiks hinnapuu tippe. Töös on toodud programmid barjääriga optsiooni hinna leidmiseks trinoommeetodi, bino- trinoommeetodi ja adaptiivsete võrede meetodi abil

Antifungal susceptibilities of aspergillus SPP. strains isolated from invasive aspergillosis cases

Çevrede ve hastane ortamında yaygın olarak bulunan Aspergillus türleri, özellikle bağışıklık sistemi yetersiz ya da baskılanmış hastalarda ciddi morbidite ve mortalite etkenidir. Bu retrospektif çalışmada, hastanede yatan hastaların klinik örneklerinden etken olarak izole edilen Aspergillus spp. suşlarının antifungal duyarlılıklarının araştırılması amaçlanmıştır. Çalışmaya, Ocak 2002-Ekim 2007 tarihleri arasında mantar enfeksiyonu şüphesi ile laboratuvarımıza gönderilen 569 hastaya ait toplam 678 örnek (420 solunum yolu örneği, 202 steril vücut sıvısı örneği, 56 biyopsi/doku örneği) dahil edilmiştir. Örnekler, beyin kalp infüzyonlu kanlı agar ve Sabouraud dekstroz agara ekilerek 25°C ve 35°C’de inkübe edilmiş; ayrıca tüm örneklerden hazırlanan Gram ve Giemsa boyalı preparatlar direkt mikroskobik olarak incelenmiştir. Küf mantarı üreyen örneklerde tanımlama konvansiyonel yöntemlerle yapılmış; olgularda “invazif aspergilloz” tanımı ise, Avrupa Kanser Araştırma ve Tedavi Kuruluşu, İnvazif Fungal Enfeksiyon Çalışma Grubunun aspergilloz tanı kriterlerine göre yapılmıştır. Çalışmada, tümünde malignite gibi altta yatan bir faktör olan 12 (%2.1) olgunun klinik örneklerinden (9 alt solunum yolu, birer asit, beyin biyopsisi ve plevral sıvı örneği) Aspergillus spp. izole edilmiş ve bu suşlar A.fumigatus (n= 8), A.flavus (n= 2) ve A.niger (n= 2) olarak tanımlanmıştır. İzolatların, kaspofungin, vorikonazol, itrakonazol ve amfoterisin B’ye karşı duyarlılıkları buyyon mikrodilüsyon yöntemiyle, posakonazole karşı duyarlılıkları ise E-test (AB Biodisk, İsveç) yöntemi ile araştırılmıştır. Aspergillus spp. suşlarında en düşük minimum inhibitör konsantrasyonu (MİK) değerleri kaspofungin ve posakonazol için (≤ 0.125 µg/ml); en yüksek MİK değerleri ise amfoterisin B için (≥ 1 µg/ml) tespit edilmiştir. Vorikonazol ve itrakonazol için, biri hariç tüm suşlarda MİK değerleri ≤ 0.5 µg/ml saptanırken, sadece bir A.niger suşunda itrakonazol için 2 µg/ml değeri elde edilmiştir. Diğer türlerin sayısının az olması nedeniyle, MİK50 değerleri sadece A.fumigatus için hesaplanmış ve A.fumigatus için en yüksek MİK50 değeri amfoterisin B (2 µg/ml) için saptanırken, en düşük MİK50 değerleri sırasıyla; posakonazol (0.064 µg/ml), kaspofungin (0.064 µg/ml), itrakonazol (0.25 µg/ml) ve vorikonazol (0.25 µg/ml) için belirlenmiştir. Sonuç olarak, suş sayımızın az olmasına rağmen, kaspofungin ve posakonazol için en düşük MİK değerlerinin tespit edilmiş olması, bu yeni antifungallerin hastanemizde aspergillozlu olguların tedavisinde akılda tutulması gereken seçenekler olduğunu vurgulamaktadır.Aspergillus species found abundantly in the outer environment and hospital setting may lead to serious morbidity and mortality particularly in patients with suppressed immunity This retrospective study was aimed to investigate the antifungal susceptibilities of Aspergillus spp isolated from aspergillosis cases being hospitalized Aspergillus spp. isolated from samples of the patients with suspected fungal infections between January of 2002 and October of 2007, were investigated A total of 678 samples (420 lower respiratory tract, 202 sterile body fluids, and 56 biopsy/tissue specimens) from 569 patients were included in the study. The samples were incubated in 25 degrees C and 35 degrees C on brain-heart-infusion agar supplemented with blood and on Sabouraud dextrose agar Gram and Giemsa stained samples were also examined by microscopy Mold type of fungi were identified by conventional techniques "Invasive aspergillosis" was described according to criteria of Invasive Fungal Infections Cooperative Group of the European Organization for Research and Treatment of Cancer. A.fumigatus (n= 8), A.flavus (n= 2) and A niger (n= 2) were isolated from 12 patients' samples (2.1%), 9 of them were lower respiratory tract and one of each was ascid, brain biopsy and pleural fluid specimens. All of those patients have had an underlying diseases such as malignancy The susceptibility of the isolates to caspofungin, voriconazole, itraconazole and amphotericin B was tested by broth microdilution susceptibility testing and to posaconazole by E-test (AB Biodisk, Sweden). The lowest minimum inhibitory concentration (MIC) ( 1 mu g/ml) MIC values of the all strains except one, were detected as <= 0 5 mu g/ml for voriconazole and itraconazole In one A niger strain itraconazole MIC value was 2 mu g/ml Since the number of other species was low, MIC(50) value was determined only for A fumigatus strains and it was found that the highest MIC(50) value was for amphotericin B (2 mu g/ml) and the lowest MIC(50) values were for posaconazole (0.064 mu g/ml), caspofungin (0 064 mu g/ml), itraconazol (0 25 mu g/ml) and voriconazol (0.25 mu g/ml). Since caspofungin and posaconazole revealed the lowest MIC values, they should be taken into consideration in choice of therapy of aspergillosis cases in our hospital

Bishop-Phelps-Bollobáse teoreem

Bakalaureusetöös esitatakse Bishop–Phelpsi tugifunktsionaalide teoreemi üksikasjalik tõestus. Tõestus järgib Bishopi ja Phelpsi originaaltõestust aastast 1963, kuid üks lemma on asendatud tema tugevdusega Phelpsi hilisemast artiklist ajakirjas Advances in Math., 1974 (järeldus 2.3), millele antakse töös lihtsam tõestus. Selline asendus võimaldab kõrvalsaadusena tõestada parimate võimalike (teada olevate) hinnangutega Bishop–Phelps–Bollobáse teoreemi