136 research outputs found
Dielectronic Recombination of Fe XV forming Fe XIV: Laboratory Measurements and Theoretical Calculations
We have measured resonance strengths and energies for dielectronic
recombination (DR) of Mg-like Fe XV forming Al-like Fe XIV via N=3 -> N' = 3
core excitations in the electron-ion collision energy range 0-45 eV. All
measurements were carried out using the heavy-ion Test Storage Ring at the Max
Planck Institute for Nuclear Physics in Heidelberg, Germany. We have also
carried out new multiconfiguration Breit-Pauli (MCBP) calculations using the
AUTOSTRUCTURE code. For electron-ion collision energies < 25 eV we find poor
agreement between our experimental and theoretical resonance energies and
strengths. From 25 to 42 eV we find good agreement between the two for
resonance energies. But in this energy range the theoretical resonance
strengths are ~ 31% larger than the experimental results. This is larger than
our estimated total experimental uncertainty in this energy range of +/- 26%
(at a 90% confidence level). Above 42 eV the difference in the shape between
the calculated and measured 3s3p(^1P_1)nl DR series limit we attribute partly
to the nl dependence of the detection probabilities of high Rydberg states in
the experiment. We have used our measurements, supplemented by our
AUTOSTRUCTURE calculations, to produce a Maxwellian-averaged 3 -> 3 DR rate
coefficient for Fe XV forming Fe XIV. The resulting rate coefficient is
estimated to be accurate to better than +/- 29% (at a 90% confidence level) for
k_BT_e > 1 eV. At temperatures of k_BT_e ~ 2.5-15 eV, where Fe XV is predicted
to form in photoionized plasmas, significant discrepancies are found between
our experimentally-derived rate coefficient and previously published
theoretical results. Our new MCBP plasma rate coefficient is 19-28% smaller
than our experimental results over this temperature range
Experimental study of fragmentation products in the reactions 112Sn + 112Sn and 124Sn + 124Sn at 1 AGeV
Production cross-sections and longitudinal velocity distributions of the
projectile-like residues produced in the reactions 112Sn + 112Sn and 124Sn +
124Sn both at an incident beam energy of 1 AGeV were measured with the
high-resolution magnetic spectrometer, the Fragment Separator (FRS) of GSI. For
both reactions the characteristics of the velocity distributions and nuclide
production cross sections were determined for residues with atomic number Z
10. A comparison of the results of the two reactions is presented.Comment: 14 pages, 12 figure
Electron-ion Recombination of Fe X forming Fe IX and of Fe XI forming Fe X: Laboratory Measurements and Theoretical Calculations
We have measured electron-ion recombination for Fe forming Fe
and for Fe forming Fe using merged beams at the TSR heavy-ion
storage-ring in Heidelberg. The measured merged beams recombination rate
coefficients (MBRRC) for relative energies from 0 to 75 eV are presented,
covering all dielectronic recombination (DR) resonances associated with 3s->3p
and 3p->3d core transitions in the spectroscopic species Fe X and Fe XI,
respectively. We compare our experimental results to multi-configuration
Breit-Pauli (MCBP) calculations and find significant differences. From the
measured MBRRC we have extracted the DR contributions and transform them into
plasma recombination rate coefficients (PRRC) for astrophysical plasmas with
temperatures from 10^2 to 10^7 K. This spans across the regimes where each ion
forms in photoionized or in collisionally ionized plasmas. For both temperature
regimes the experimental uncertainties are 25% at a 90% confidence level. The
formerly recommended DR data severely underestimated the rate coefficient at
temperatures relevant for photoionized gas. At the temperatures relevant for
photoionized gas, we find agreement between our experimental results and MCBP
theory. At the higher temperatures relevant for collisionally ionized gas, the
MCBP calculations yield a Fe XI DR rate coefficent which is significantly
larger than the experimentally derived one. We present parameterized fits to
our experimentally derived DR PRRC.Comment: 44 Pages, 5 Figures. Accepted for publication in Astrophys.
Environmental constraint of intraguild predation: Inorganic turbidity modulates omnivory in fairy shrimps
Omnivory is widespread in food webs, with an important stabilising effect. The strength of omnivorous trophic interactions may change considerably with changes in the local environment. Shallow temporary waters are often characterised by high levels of inorganic turbidity that may directly limit the food uptake of filter-feeding organisms, but there is little evidence on how it might affect omnivorous species. Anostracans are key species of temporary waters and recent evidence suggests that these organisms are omnivorous consumers of both phyto- and zooplankton. Using Branchinecta orientalis as a model species, our aim was to test how turbidity affects the feeding of an omnivorous anostracan. To do this, we used short-term feeding experiments and stable isotope analyses, with animals collected from soda pans in eastern Austria. In the feeding experiments, algae and zooplankton were offered as food either separately or in combination. The prey type treatments were crossed with turbidity levels in a factorial design. There was a pronounced decrease in the ingested algal biomass with increasing turbidity. Conversely, ingestion rates on zooplankton were less affected by turbidity. Stable isotope analyses from field material supported our experimental results by showing a positive relationship of the trophic position of anostracans and the trophic niche of the communities with turbidity. Our results show that turbidity modulates the intraguild trophic relationship between anostracans and their prey by shifting the diet of anostracans from more herbivorous in transparent to more carnivorous in turbid waters. Thus, inorganic turbidity might also have a community-shaping role in plankton communities of temporary waters through altering trophic relationships
Astrophysical Relevance of Storage-Ring Electron-Ion Recombination Experiments
The relevance of storage-ring electron-ion recombination experiments for
astrophysics is outlined. In particular, the role of low-energy
dielectronic-recombination resonances is discussed. A bibliographic compilation
of electron-ion recombination measurements with cosmically abundant ions is
provided.Comment: 8 pages, 3 figures, 1 table, 77 references, Proceedings of the 14th
International Conference on the Physics of Highly Charged Ions, Cofu, Tokyo,
Septmber 1-5, 2008, to be published in J. Phys. Conf. Se
Forest fire analysis and classification based on a Serbian case study
A recent forest fire in the Republic of Serbia is discussed concerning classification, legislative framework and fire management, giving a detailed analysis of the forest fire occurrence. Analysing past and predicting future fires are crucial for policy development and forest management practices to prevent and mitigate fires. Fire hazard is discussed through several fire protection and prevention legislative documents. The nonparametric Mann-Kendall test was used to analyse resent forest fire data in an attempt to find causality in occurrences and frequency. The meteorological data and fire statistics provided by the Serbian Hydro-meteorological Service and the Ministry of Interior/Sector for Emergency Management of the Republic of Serbia were used to calculate the Forest Fire Weather Indices, along with deficit or surplus of precipitation for the case study of Tara Mountain. The paper highlights the need for better hierarchical classification of fire hazards and its harmonisation along with standardisations presented by leading international research institutions. A significant correlation between meteorological parameters and forest fire occurrence was found. This opens a possibility for further investigation and analysis of geophysical and anthropogenic driven factors that can influence disaster occurrence
The Formation of the First Massive Black Holes
Supermassive black holes (SMBHs) are common in local galactic nuclei, and
SMBHs as massive as several billion solar masses already exist at redshift z=6.
These earliest SMBHs may grow by the combination of radiation-pressure-limited
accretion and mergers of stellar-mass seed BHs, left behind by the first
generation of metal-free stars, or may be formed by more rapid direct collapse
of gas in rare special environments where dense gas can accumulate without
first fragmenting into stars. This chapter offers a review of these two
competing scenarios, as well as some more exotic alternative ideas. It also
briefly discusses how the different models may be distinguished in the future
by observations with JWST, (e)LISA and other instruments.Comment: 47 pages with 306 references; this review is a chapter in "The First
Galaxies - Theoretical Predictions and Observational Clues", Springer
Astrophysics and Space Science Library, Eds. T. Wiklind, V. Bromm & B.
Mobasher, in pres
Development of SARS-CoV-2 N-protein specific capture ELISA
Ta na dijagnoza ljudi sa sumnjom na infekciju SARS-CoV-2 je od suštinskog zna aja zasuzbijanje globalnog širenja COVID-19. Prisustvo SARS-CoV-2 može se otkriti RT-PCRom (otkriva RNK virusa) ili detekcijom prisustva virusnih antigena u biološkim te nostimaELISA-om ili sli nom tehnikom koje koriste antitela razvijena u životinjama. Cilj studijeje bio uspostavljanje kvantitativnog testa koji se zasniva na koriš enju poliklonskih serumaza rutinsko odre ivanje koncentracije SARS-CoV-2 nukleokapsidnog proteina merenjamapsorbancije u standardnoj mikrotitarskoj plo ici sa 96 bunara. Za potrebe razvoja testaproizveden je rekombinantni N-protein i koriš en za proizvodnju antiseruma u miševima ize evima. Proizvedeni antiserumi su pre iš eni i odre en im je titar. Poliklonskiantiserumivisokog afiniteta specifi ni za N-protein koriš eni su za razvoj ELISA testa specifi nog zaovaj protein. Test se zasniva na koriš enju poliklonskih seruma miševa koji su adheriranina dno bunara mikrotitarske plo ice za hvatanje N-proteina iz uzorka. Razli itekoncentracije rekombinantnog N-proteina su koriš ene za standardnu krivu zakvantifikaciju proteina. N-protein vezan za antitela miševa je detektovan ze jimpoliklonskim serumom i anti-ze jim antitelom povezanim sa enzimom koji obezbe ujespektrofotometrijsko merenje. Uspešno smo razvili prototip ELISA testa za kvantifikacijuN-proteina sa granicom detekcije u opsegu od ng/mL. Prose na vrednost LOD za prototipELISA testa za detekciju N-proteina je 9,2 ng/mL, dok je prose na vrednost LOQ10,2 ng/mL. Pokazali smo da su proizvedeni poliklonski antiserumi pogodni za detekcijuN-proteina sa sli nim ili boljim afinitetom i specifi noš u od komercijalnih antitela.Štaviše, prototip ELISA testa se može koristiti sa zadovoljavaju om pouzdanoš u zakvantifikaciju N-proteina u uzorcima bogatim proteinima, poput ljudskih seruma.The accurate diagnosis of people with suspected infection with the SARS-CoV-2 isessential to curb the global spread of COVID-19. The presence of SARS-CoV-2 can bedetected by RT-PCR (it detects RNA of the virus) or by the presence of viral antigens inbiological fluids in ELISA or similar techniques using antibodies developed in animals.The aim of the study was the establishment of a quantitative polyclonal sera-based test forroutine measurement of the concentration of SARS CoV-2 nucleocapsid protein usingabsorbance measurement in a standard 96-well microtiter plate. For the purposes of the testdevelopment, recombinant N protein was produced and used for the production of miceand rabbit antisera. Produced antisera were purified and titer was determined. High-affinitypolyclonal N-protein specific antisera were used for N-protein specific ELISA testdevelopment. The test is based on mice polyclonal sera adhered to microtiter plate bottomfor the capture of the N protein from the specimen. Various concentrations of therecombinant N-protein were used to generate a standard curve for protein quantification.The N-protein bound to the mice antibodies was detected with rabbit polyclonal sera andanti-rabbit antibody coupled to an enzyme that provides spectrophotometric measurement.We have successfully developed the prototype ELISA for the quantification of N-proteinwith the detection limit being in the range of ng/mL. The average LOD value for theprototype ELISA was determined to be 9.2 ng/mL, while the average LOQ value was10.2 ng/mL. We have demonstrated that produced polyclonal antisera are suitable for thedetection of N-protein with affinity and specificity similar to, or better than commercialantibodies. Furthermore, the prototype ELISA can be used with satisfactory confidence forquantification of the N-protein in protein-rich samples, similar to human sera.Abstract: [https://cherry.chem.bg.ac.rs/handle/123456789/5361
Development of SARS-CoV-2 N-protein specific capture ELISA
Ta na dijagnoza ljudi sa sumnjom na infekciju SARS-CoV-2 je od suštinskog zna aja za
suzbijanje globalnog širenja COVID-19. Prisustvo SARS-CoV-2 može se otkriti RT-PCRom (otkriva RNK virusa) ili detekcijom prisustva virusnih antigena u biološkim te nostima
ELISA-om ili sli nom tehnikom koje koriste antitela razvijena u životinjama. Cilj studije
je bio uspostavljanje kvantitativnog testa koji se zasniva na koriš enju poliklonskih seruma
za rutinsko odre ivanje koncentracije SARS-CoV-2 nukleokapsidnog proteina merenjam
apsorbancije u standardnoj mikrotitarskoj plo ici sa 96 bunara. Za potrebe razvoja testa
proizveden je rekombinantni N-protein i koriš en za proizvodnju antiseruma u miševima i
ze evima. Proizvedeni antiserumi su pre iš eni i odre en im je titar. Poliklonskiantiserumi
visokog afiniteta specifi ni za N-protein koriš eni su za razvoj ELISA testa specifi nog za
ovaj protein. Test se zasniva na koriš enju poliklonskih seruma miševa koji su adherirani
na dno bunara mikrotitarske plo ice za hvatanje N-proteina iz uzorka. Razli ite
koncentracije rekombinantnog N-proteina su koriš ene za standardnu krivu za
kvantifikaciju proteina. N-protein vezan za antitela miševa je detektovan ze jim
poliklonskim serumom i anti-ze jim antitelom povezanim sa enzimom koji obezbe uje
spektrofotometrijsko merenje. Uspešno smo razvili prototip ELISA testa za kvantifikaciju
N-proteina sa granicom detekcije u opsegu od ng/mL. Prose na vrednost LOD za prototip
ELISA testa za detekciju N-proteina je 9,2 ng/mL, dok je prose na vrednost LOQ
10,2 ng/mL. Pokazali smo da su proizvedeni poliklonski antiserumi pogodni za detekciju
N-proteina sa sli nim ili boljim afinitetom i specifi noš u od komercijalnih antitela.
Štaviše, prototip ELISA testa se može koristiti sa zadovoljavaju om pouzdanoš u za
kvantifikaciju N-proteina u uzorcima bogatim proteinima, poput ljudskih seruma.The accurate diagnosis of people with suspected infection with the SARS-CoV-2 is
essential to curb the global spread of COVID-19. The presence of SARS-CoV-2 can be
detected by RT-PCR (it detects RNA of the virus) or by the presence of viral antigens in
biological fluids in ELISA or similar techniques using antibodies developed in animals.
The aim of the study was the establishment of a quantitative polyclonal sera-based test for
routine measurement of the concentration of SARS CoV-2 nucleocapsid protein using
absorbance measurement in a standard 96-well microtiter plate. For the purposes of the test
development, recombinant N protein was produced and used for the production of mice
and rabbit antisera. Produced antisera were purified and titer was determined. High-affinity
polyclonal N-protein specific antisera were used for N-protein specific ELISA test
development. The test is based on mice polyclonal sera adhered to microtiter plate bottom
for the capture of the N protein from the specimen. Various concentrations of the
recombinant N-protein were used to generate a standard curve for protein quantification.
The N-protein bound to the mice antibodies was detected with rabbit polyclonal sera and
anti-rabbit antibody coupled to an enzyme that provides spectrophotometric measurement.
We have successfully developed the prototype ELISA for the quantification of N-protein
with the detection limit being in the range of ng/mL. The average LOD value for the
prototype ELISA was determined to be 9.2 ng/mL, while the average LOQ value was
10.2 ng/mL. We have demonstrated that produced polyclonal antisera are suitable for the
detection of N-protein with affinity and specificity similar to, or better than commercial
antibodies. Furthermore, the prototype ELISA can be used with satisfactory confidence for
quantification of the N-protein in protein-rich samples, similar to human sera.Poster: [https://cherry.chem.bg.ac.rs/handle/123456789/5362
Philosophy of law in the Soviet Union and the people’s democracies
The fate of Marxism in the Soviet Union and the people’s democracies as the former’s extension owing to post-WWII occupation was from the beginning sealed by Bolshevism, that is, the politico-ideological domination and use of the scholarly domain as well, made to self-close in a merely justificatory role. There may have been attempts at opening, even if only conceivable within—i.e. preserving at the same time—this framework function. In the present conspectus, the limiting positions are occupied by the Soviet Union and the German Democratic Republic, completed by after-1968 Czechoslovakia, as well as Yugoslavia and pre-1968 Czechoslovakia, representing the substitute-to-religion dogmatic side, exclusively politically motivated in the former and subordinated to a humanising tendency in the latter case, on the one hand, and Poland, dedicated to a purely analytical approach, in which Marxism has simply no relevance, on the other. Hungary, treated in an earlier paper by the author, was in-between, taking Marxism seriously but mostly as a methodology, and thereby able to foster live debates. All that notwithstanding, there has been quite a few progressive moves also in Romania and Bulgaria in this specific academic field. Turning topoi of the discussions were, chronologically but recurrent transubstantiatedly, the exclusivity of Vyshinsky’s socialist normativism, the consequences ensuing from the law’s superstructural nature, the discontinuity vs. continuity of law in historical development, and, in the background, the dilemma of the ontological/epistemological understanding of Marxism, the latter standing for a rigid Leninist reducibility of law to its material substratum as the product of sheer reflection, and the former enabling to develop the law’s relative autonomy as in Lukács’ posthumous ontology. On the final analysis, all these forced paths made a whole region’s efforts to be belated as compared to international developments, the fact notwithstanding those outstanding achievements were born especially on the fields of legal ontology and sociology, as well as the legal methodology and particularly that of the comparison of laws
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