94 research outputs found

    Flattened Galactic Haloes and Baryonic Dark Matter

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    We discuss the tight interconnection between microlensing optical depths, flattening of dark haloes and low-to-intermediate redshift baryonic census. By analysing plots of the microlensing optical depth as a function of galactic coordinates for different values of axis ratio qq of the galactic MACHO halo, we have shown that observations are best described by a flattened halo with q0.6q \simeq 0.6. There is no dynamical obstacle for such a choice of global halo shape. Both extremely flattened q0.2q \simeq 0.2 and spherical q1q \simeq 1 haloes have several difficulties, although not of equal severity. Consequences of such flattening for the cosmological density fraction contained in MACHOs are considered and comparison with mass in low and intermediate-redshift Lyα\alpha forest and other plausible reservoirs of gas is discussed in context of a unified description of the evolution of baryonic content of the universe.Comment: 14 pages, 15 figures, TeX, uses mn.tex and psfig.tex, MNRAS accepte

    Poređenje kvaliteta mesa linjaka i šarana

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    U poslednje dve godine postoje veliki problemi u plasmanu slatkovodnih riba proizvedenih na našim ribnjacima. Zahvaljujući nekontrolisanom uvozu, došlo je do toga da se na našem tržištu nađe velika količina jeftinih vrsta riba, pre svega Pangasius pangasius iz Vijetnama , čiji je uvoz zabranjen u mnogim razvijenim zemljama, pre svega SAD, Kanadi i većem broju zemalja Evropske Unije. Velprodajna cena šarana je veoma niska, pa je doveden u pitanje opstanak naše ribarske privrede, u čijoj strukturi šaran učestvuje najvećim delom. Stoga je potrebno razmišljati o uvođenju drugih slatkovodnih vrsta koje bi se mogle plasirati na tržište Evropske Unije, što se pre svega odnosi na linjaka. Takođe, treba razmišljati i o organskoj proizvodnji riba i o kreatnju ka ekstenzivnijim metodama gajenja. Neophodno je voditi računa i o nutritivnom kvalitetu mesa jer se od ribarske privrede očekuje proizvod sa niskim sadržajem masti i povoljnim odnosom nezasićenih masnih kiselina, pre svega ω-3 i ω-6 masnih kiselina. Poznat je povoljan uticaj ω-3 polinezasićenih masnih kiselina (PNMK) iz mesa ribe na zdravlje čoveka, kao i da povećana potrošnja ribe utiče na sprečavanje nastanka oboljenja kardiovaskularnog sistema, kao i u prevenciji inflamatornih, autoimunih i malignih oboljenja, dijabetesa i drugih bolesti. Literalni podaci o randmanu dvogodišnjih riba linjaka i šarana su veoma oskudni, dok su dostupne informacije o konzumnim ribama koje su starosti tri i više godina. Kako kvalitet mesa zavisi od starosti jedinke, neophodna su istraživanja i o kvalitetu mesa mlađih kategorija riba. Osim randmana analizirani su i hemijski sastav mesa dvogodišnjeg linjaka i šarana sa akcentom na zastupljenost masnih kiselina i poređenje odnosa ovih vrednosti kod linjaka i šarana. Uzorci dvogodišnjeg linjaka i šarana uzeti su na oglednom ribnjaku "Mošorin". Proizvodnja ovih riba odvijala se u ekstenzivnom sistemu, gde je povećanje organske produkcije vršeno pregorelim goveđim i ovčijim stajnjakom. Ishrana dodatnim hranivima nije vršena. U pripremi objekta i tokom vegetacionog perioda korišćen je hidratni kreč. Analize hemijskog sastava i masnokiselinskog sastava lipida ribe su izvršene u Institutu za higijenu i tehnologiju mesa, Beograd. Analizom morfometrijskih karakteristika ribe utvrđena je dobra kondicija. Randman mesa linjaka povoljniji je od istoga kod šarana što se može objasniti manjom masom digestivnog trakta ove vrste. Razlog za niži procenat proteina kod linjaka i kod šarana nego što je to prikazivano u klasičnoj literaturi je što se radi o mesu dvogodišnjih riba dok se pomenuti literaturni podaci odnose na starije kategorije koje imaju manji sadržaj vode. Veći sadržaj vode kod dvogodišnjih riba doprinosi boljem gastronomskom kvalitetu mesa. Po sadržaju masti meso linjaka je približno vrednostima tolstolobika i amura, iz čega se može zaključiti da je veoma pogodno kao dijetalna hrana za potrebe posebnih zdravstvenih kategorija ljudi. I dvogodišnji šaran ima nizak procenat masti iz čega se može zaključiti da šaran ne spada u masne ribe jer ima niži procenat sadržaja masti od pastrmke. Tehnologija gajenja odnosno vrsta dodatne ishrane je najodgovornija za procenat masti. Odnos nezasićenih masnih kiselina kod linjaka povoljniji je nego kod šarana i pastrmke i u sličnom nivou je sa istim kod morskih vrsta riba. Meso dvogodišnjih riba po svom hemijskom sastavu ima prednost u odnosu na meso riba gajenih u trogodišnjem i višegodišnjem sistemu gajenja. Ekstenzivni sistem ima prednost u kvalitetu mesa ali treba analizirati njegovu ekonomsku opravdanost. Kvalitet mesa linjaka je izuzetnih nutritivnih vrednosti što je razlog za njegovu reintrodukciju i repopulaciju. Meso riba visoke nutritivne vrednosti ima perspektivu kao izvozni artikal u zemlje Evropske Unije i druge razvijene zemlje

    Determination of Capacity and Rules of the Variability of Maximum Force Using Nonlinear Mathematical Models: a Case Study.

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    The aim of this study is to determine the capacity and the variability of maximum force rules measured 1 RM for eight muscle groups (back-hip extensors, legs extensors, arm extensors, back extensors, shoulder and arms extensors, shoulder joint flexors, hip and knee extensors, trunk flexors). The determination was performed on the experimental results of the top basketball center player using repeated measurements and nonlinear mathematical models methods. Changes in maximum force were induced with 8 months of weight lifting training and analised with nonlinear regression analysis within 95% confidence interval. The results indicate that from all the models applied only the Asymptotic Regression, Michaelis-Menten and Gompertz Growth models had satisfactory performance and provided solid solutions to the given problem. This means that the models developed in this study properly and reliably determine the capacity and predicted changes in the maximum force (1 RM) for all eight monitored muscle groups

    Structural, morphological and luminescence properties of nanocrystalline up-converting Y1.89Yb0.1Er0.01O3 phosphor particles synthesized through aerosol route

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    Nanocrystalline up-converting Y₂ O₃Yb³⁺ Er³⁺ phosphor particles were processed in a dispersed system-aerosol, generated ultrasonically at 1.3 MHz from common nitrate precursor solution having fixed ytterbium-to-erbium concentration ratio. The appropriate process parameters: residence time 21 s, carrier gas (air) flow rate 1.6 dm3/min, synthesis temperature 900 °C, led to the formation of un-agglomerated spherical nanostructured secondary particles, having mean particle size of approx 450 nm, composed of primary nanoscaled (20 nm) subunits. In order to reach targeting phase crystallinity, the as-prepared particles were additionally annealed at 1100 °C in air for 12, 24 and 48 h, respectively. Particle structure, morphology and purity were analyzed by X-ray powder diffraction (XRPD), scanning electron microscopy (FESEM/SEM), analytical and high resolution transmission electron microscopy (TEM/HRTEM) in combination with energy dispersive X-ray analysis and Fourier Transform Infrared Spectroscopy (FTIR). All samples crystallized in a cubic bixbyte-structure, space group Ia-3. The crystallite size changed with annealing time from 30 nm in as-prepared sample to 135 nm in sample annealed for 48 h, respectively. Emission spectra were assigned to the following trivalent erbium f–f electronic transitions: ²H₉/₂ → ⁴I₁₅/₂ (blue: 407–420 nm), (²H₁₁/₂̦ ⁴S₃/₂) → ⁴I₁₅/₂ (green: 510–590 nm), and ⁴F₉/₂ → ⁴I₁₅/₂ (red: 640–720 nm). The significant improvement of the emission decay times were observed after thermal treatment and this effect is correlated further with the structural and morphological particles characteristics. For the anneal-ing time of 12 h a quite high emission decay times were achieved (blue: 0.14 ms, green: 0.32 ms and red: 0.39 ms).This research is financially supported through the Project #172035 of the Ministry of Science and Education of the Republic of Serbia. OM especially acknowledge the University Carlos III, Madrid, Spain-Santander Bank Chairs of Excellence program and JSPS 2011/2012 fellowship, Japan.Publicad

    Development of Expert System for the Selection of 3D Digitization Method in Tangible Cultural Heritage

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    Selection of an appropriate 3D digitization method in the field of cultural heritage represents a big challenge, especially for non-expert users, such as conservators, art historians, archaeologists etc. Considering the above, the aim of this paper is to develop an expert system for the selection of 3D digitization method, which is the tool for suggesting for the most acceptable 3D digitization method for any individual cultural heritage object. The development of the expert system was presented through the analysis of its components, i.e. main modules – user interface, database and knowledge base. This expert system was based on different parameters defined through theoretical-methodological analysis of representative tangible cultural heritage objects. The database contains technical specifications of various 3D digitization methods, devices, and additional equipment available on market, while the knowledge base defines their limitations. The expert selection system requires as input information details about the cultural heritage object and the end user requirements. During the evaluation phase through the case studies, the system proposed satisfactory solutions depending on the entered input data

    Analysis of Linear Antibody Epitopes on Factor H and CFHR1 Using Sera of Patients with Autoimmune Atypical Hemolytic Uremic Syndrome

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    Introduction: In autoimmune atypical hemolytic uremic syndrome (aHUS), the complement regulator factor H (FH) is blocked by FH autoantibodies, while 90% of the patients carry a homozygous deletion of its homolog complement FH-related protein 1 (CFHR1). The functional consequence of FH-blockade is widely established; however, the molecular basis of autoantibody binding and the role of CFHR1 deficiency in disease pathogenesis are still unknown. We performed epitope mapping of FH to provide structural insight in the autoantibody recruitment on FH and potentially CFHR1. Methods: Eight anti-FH positive aHUS patients were enrolled in this study. With overlapping synthetic FH and CFHR1 peptides, we located the amino acids (aa) involved in binding of acute and convalescence stage autoantibodies. We confirmed the location of the mapped epitopes using recombinant FH domains 19-20 that carried single-aa substitutions at the suspected antibody binding sites in three of our patients. Location of the linear epitopes and the introduced point mutations was visualized using crystal structures of the corresponding domains of FH and CFHR1. Results: We identified three linear epitopes on FH (aa1157-1171; aa1177-1191; and aa1207-1226) and one on CFHR1 (aa276-290) that are recognized both in the acute and convalescence stages of aHUS. We observed a similar extent of autoantibody binding to the aHUS-specific epitope aa1177-1191 on FH and aa276-290 on CFHR1, despite seven of our patients being deficient for CFHR1. Epitope mapping with the domain constructs validated the location of the linear epitopes on FH with a distinct autoantibody binding motif within aa1183-1198 in line with published observations. Summary: According to the results, the linear epitopes we identified are located close to each other on the crystal structure of FH domains 19-20. This tertiary configuration contains the amino acids reported to be involved in C3b and sialic acid binding on the regulator, which may explain the functional deficiency of FH in the presence of auto antibodies. The data we provide identify the exact structures involved in autoantibody recruitment on FH and confirm the presence of an autoantibody binding epitope on CFHR1.Peer reviewe

    Hepatitis B Outbreak Among Men Who Have Sex with Men in the Autonomous Province of Vojvodina, Serbia

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    ** From Crossref via Jisc Publications Router.The European Centre for Disease Prevention and Control reported that there were 2896 acute hepatitis B cases in 24 EU/EEA countries in 2013.1 The incidence ranged from 0.1 cases per 100,000 in France and Portugal to 4.3 per 100,000 in Latvia, with a male-to-female ratio of 2.2:1 in EU/EEA countries, and transmission among men who have sex with men (MSM) reported in 9.4% of all cases of acute hepatitis B.1 Some authors consider hepatitis B virus (HBV) infection to be endemic in the MSM population with the incidence 20 times higher in MSM than in the general population worldwide.2 However, data on HBV prevalence among MSM are available for only four EU/EEA countries.3 Six to ten percent of MSM infected with HBV worldwide are co-infected with HIV.4sch_iih5pub4999pub

    Interactive histogenesis of axonal strata and proliferative zones in the human fetal cerebral wall

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    Development of the cerebral wall is characterized by partially overlapping histogenetic events. However, little is known with regards to when, where, and how growing axonal pathways interact with progenitor cell lineages in the proliferative zones of the human fetal cerebrum. We analyzed the developmental continuity and spatial distribution of the axonal sagittal strata (SS) and their relationship with proliferative zones in a series of human brains (8-40 post-conceptional weeks; PCW) by comparing histological, histochemical, and immunocytochemical data with magnetic resonance imaging (MRI). Between 8.5 and 11 PCW, thalamocortical fibers from the intermediate zone (IZ) were initially dispersed throughout the subventricular zone (SVZ), while sizeable axonal "invasion" occurred between 12.5 and 15 PCW followed by callosal fibers which "delaminated" the ventricular zone-inner SVZ from the outer SVZ (OSVZ). During midgestation, the SS extensively invaded the OSVZ, separating cell bands, and a new multilaminar axonal-cellular compartment (MACC) was formed. Preterm period reveals increased complexity of the MACC in terms of glial architecture and the thinning of proliferative bands. The addition of associative fibers and the formation of the centrum semiovale separated the SS from the subplate. In vivo MRI of the occipital SS indicates a "triplet" structure of alternating hypointense and hyperintense bands. Our results highlighted the developmental continuity of sagittally oriented "corridors" of projection, commissural and associative fibers, and histogenetic interaction with progenitors, neurons, and glia. Histogenetical changes in the MACC, and consequently, delineation of the SS on MRI, may serve as a relevant indicator of white matter microstructural integrity in the developing brain
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