2,065 research outputs found
Airy-function electron localization in the oxide superlattices
Oxide superlattices and microstructures hold the promise for creating a new
class of devices with unprecedented functionalities. Density-functional studies
of the recently fabricated superlattices of lattice-matched perovskite
titanates (SrTiO3)n/(LaTiO3)m reveal a classic wedge-shaped potential
originating from the Coulomb potential of a charged sheet of La atoms. The
potential in turn confines the electrons in the vicinity of the sheet, leading
to an Airy-function localization of the electron states. Magnetism is
suppressed for structures with a single LaTiO3 monolayer, while the bulk
antiferromagnetism is recovered in the structures with a thicker LaTiO3, with a
narrow transition region separating the magnetic LaTiO3 and the non-magnetic
SrTiO3
DEVELOPMENT OF SMES IN AGRIBUSINESS OF VOJVODINA COMMUNES - STATE AND PERSPECTIVES
Agriculture as the economic sector is an important factor of economic development of Serbia and an important part of economic structure. Serbia has agrarian resources (land, climate and water) that are not used enough, and therefore, represent a significant economic potential for further development. Vojvodina is the best-developed economic region of the Republic of Serbia, with dominant role of agricultural production. The main economic potential of Vojvodina development is, among other things, the strengthening and improvement of agriculture in the private sector. Economic potential of agriculture impose the need to analyze this situation in the field of small and medium sized entrepreneurship as the bearer of the future development of agriculture in Vojvodina. Cluster analysis is a method that will determine how to group communes in Vojvodina according to the level of development of small and medium-sized enterprises in the field of agriculture, and thus get an insight into the current state of development of this sector of agriculture, as well as point out the possibilities for the future development of SMEs in agribusiness of Vojvodina.Agricultural production, Small and medium sized enterprises (SMEs), Clusters analysis, Clustering of communes in Vojvodina, Agribusiness, Community/Rural/Urban Development, Public Economics,
Electronic structure of the substitutional versus interstitial manganese in GaN
Density-functional studies of the electron states in the dilute magnetic
semiconductor GaN:Mn reveal major differences for the case of the Mn impurity
at the substitutional site Mn_Ga versus the interstitial site Mn_I. The
splitting of the two-fold and the three-fold degenerate Mn(d)states in the gap
are reversed between the two cases, which is understood in terms of the
symmetry-controlled hybridization with the neighboring atoms. In contrast to
Mn_Ga, which acts as a deep acceptor, Mn_I acts as a donor, suggesting the
formation of Coulomb-stabilized complexes such as (Mn_Ga Mn_I Mn_Ga), where the
acceptor level of Mn_Ga is passivated by the Mn_I donor. Formation of such
passivated clusters might be the reason for the observed low carrier-doping
efficiency of Mn in GaN. Even though the Mn states are located well inside the
gap,the wave functions are spread far away from the impurity center. This is
caused by the hybridization with the nitrogen atoms, which acquire small
magnetic moments aligned with the Mn moment. Implications of the differences in
the electronic structure for the optical properties are discussed
Screening of drought oxidative stress tolerance in Serbian melliferous plant species
This study was designed to examine and compare antioxidant and free-radical scavenging activities of leaves of six different melliferous plant species (Populus alba, Robinia pseudoacacia, Sophora japonica, Euodia hupehensis, Tilia sp., Fraxinus sp.) from Serbia in order to evaluate their drought oxidative stress tolerance. Experiment was conducted during June, July and August. In this study, we reported the results concerning proline accumulation, soluble protein content, quantities of malonyldialdehyde,total antioxidant capacity determined by FRAP method and scavenger activity determined by DPPH method. According to our results, all melliferous plant species were subjected to drought oxidative stress during July when soil humidity decreased. During July, proline content and MDA quantity increased and soluble proteins decreased in all investigated species. High and permanent antioxidant activity during the whole investigated period was observed in P. alba, but insufficient to protect itsleaves from oxidative injury during the period of drought in July. The highest ability to accumulate proline and highest protein content under severe drought stress in July was observed in Fraxinus sp. Other investigated antioxidant parameters (total antioxidant and DPPH radical scavenger capacities) were high and accumulation of MDA was low which indicate high drought oxidative stress tolerance. Therefore, highest ability to adapt under severe drought stress and highest drought oxidative stresstolerance were observed in Fraxinus sp.Key words: Melliferous trees, lipid peroxidation, DPPH, FRAP, proline accumulation
Factorial analysis of slaughter characteristics of fattening pigs fed different additives β Enzyme and probiotic in mixtures
To successfully investigate slaughter characteristics of fattening pigs fed in different ways, this experiment was carried out on Experimental Farm of the Institute for Animal Husbandry, Belgrade- Zemun. Investigation of correlation between slaughter traits of pigs fed with different additives in their nutrition was done by factorial analysis. Slaughter characteristics in three groups of fattening pigs fed in different ways were observed. The first group (variant 1) consisted of fatteners fed diets without any special additives. The second group (variant 2) consisted of pigs fed diets containing enzyme Rovabio, and the third group (variant 3) probiotic Lacture + Microbond. This study was aimed at coming to conclusion based on the results of factorial analysis of the observed traits to the greatest extent which determined slaughter traits of pigs fed diets containing different additives. The results obtained in general, that is, the structure of separated factors showed that different slaughter characteristics are realized with different nutrition.Key words: Fattening pigs, slaughter characteristics, enzyme Rovabio, probiotic Lacture + Microbond, factorial analysis
Electronic structure of the substitutional vacancy in graphene: Density-functional and Green's function studies
We study the electronic structure of graphene with a single substitutional
vacancy using a combination of the density-functional, tight-binding, and
impurity Green's function approaches. Density functional studies are performed
with the all-electron spin-polarized linear augmented plane wave (LAPW) method.
The three dangling bonds adjacent to the vacancy introduce
localized states (V) in the mid-gap region, which split due to the
crystal field and a Jahn-Teller distortion, while the states
introduce a sharp resonance state (V) in the band structure. For a planar
structure, symmetry strictly forbids hybridization between the and the
states, so that these bands are clearly identifiable in the calculated
band structure. As for the magnetic moment of the vacancy, the Hund's-rule
coupling aligns the spins of the four localized V, V, and the V electrons resulting
in a S=1 state, with a magnetic moment of , which is reduced by about
due to the anti-ferromagnetic spin-polarization of the band
itinerant states in the vicinity of the vacancy. This results in the net
magnetic moment of . Using the Lippmann-Schwinger equation, we
reproduce the well-known decay of the localized V wave function
with distance and in addition find an interference term coming from the two
Dirac points, previously unnoticed in the literature. The long-range nature of
the V wave function is a unique feature of the graphene vacancy and we
suggest that this may be one of the reasons for the widely varying relaxed
structures and magnetic moments reported from the supercell band calculations
in the literature.Comment: 24 pages, 15 figures. Accepted for publication in New Journal of
Physic
Π ΠΎΠ»Ρ ΡΠ°ΠΊΡΠΎΡΠ° Π½Π΅ΠΊΡΠΎΠ·Π° ΠΎΠΏΡΡ ΠΎΠ»ΠΈ-Π°Π»ΡΡΠ° Π² ΠΏΡΠΎΠ³Π½ΠΎΠ·ΠΈΡΠΎΠ²Π°Π½ΠΈΠΈ ΡΡΠΆΠ΅ΡΡΠΈ ΠΈ ΠΈΡΡ ΠΎΠ΄Π° ΡΠ΅ΠΏΡΠΈΡΠ° Ρ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ² Π½Π΅ΠΎΡΠ»ΠΎΠΆΠ½ΠΎΠ³ΠΎ ΠΎΡΠ΄Π΅Π»Π΅Π½ΠΈΡ Ρ ΡΠΈΡΡΠ΅ΠΌΠ½ΡΠΌ Π²ΠΎΡΠΏΠ°Π»Π΅Π½ΠΈΠ΅ΠΌ
Aim of the study was to determine whether the TNF-a levels, proximal inflammatory mediator, in septic patients presenting to the emergency department (ED) and admitted to the intensive care unit (ICU) are associated with progression to severe sepsis, septic shock or death. Material and methods. A retrospective observational study was performed on a sample of one hundred adult subjects presenting to the ED with systemic inflammatory response syndrome of 2 etiologies: presumed (and later confirmed in the ICU and/or operating room) severe acute pancreatitis or generalized peritonitis. Blood TNF-a samples measurements were taken shortly after ED admission. TNF-a was measured by commercial ELISA test in plasma. Results. Mean values of TNF-a on admission (day zero, in ED) were 191,5-fold lower in group with septic shock compared to severe sepsis group and were 63-fold higher in survivors (p<0.01). The area under the curve (AUC) for the TNF-a plots for severity of clinical status was 0.813 and for outcome 0.834. Patients with TNF-a levels lower than 7.95 pg/mL had a 3.2-fold higher probability of septic shock development than those with higher values, at the cutoff level sensitivity was 83,9% and specificity 72,5%. Patients with TNF-a levels higher than 10.5 pg/mL had a 4.8-fold higher probability to survive than those with lower values, at the cutoff level sensitivity was 83,0% and specificity 77,4%. Conclusion: Decreasing in TNF-a concentration leads to the septic shock development and fatal outcome. TNF-a is very good predictor of sepsis severity and outcome. Key words: sepsis, tumor necrosis factor-alpha, emergency medical services, survival rate, severity of illness index.Π¦Π΅Π»Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ β ΠΎΠΏΡΠ΅Π΄Π΅Π»ΠΈΡΡ, ΡΠ²ΡΠ·Π°Π½Ρ Π»ΠΈ ΡΡΠΎΠ²Π½ΠΈ Π€ΠΠ-a, ΠΊΠ»ΡΡΠ΅Π²ΠΎΠ³ΠΎ ΠΌΠ΅Π΄ΠΈΠ°ΡΠΎΡΠ° Π²ΠΎΡΠΏΠ°Π»Π΅Π½ΠΈΡ, Ρ ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ² Ρ ΡΠ΅ΠΏΡΠΈΡΠΎΠΌ, ΠΏΠΎΡΡΡΠΏΠ°ΡΡΠΈΡ
Π² ΠΎΡΠ΄Π΅Π»Π΅Π½ΠΈΠ΅ Π½Π΅ΠΎΡΠ»ΠΎΠΆΠ½ΠΎΠΉ ΠΏΠΎΠΌΠΎΡΠΈ ΠΈ ΠΏΠ΅ΡΠ΅Π²ΠΎΠ΄ΡΡΠΈΡ
ΡΡ Π² ΠΎΡΠ΄Π΅Π»Π΅Π½ΠΈΠ΅ ΡΠ΅Π°Π½ΠΈΠΌΠ°ΡΠΈΠΈ, Ρ ΠΏΡΠΎΠ³ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ Π΅Π³ΠΎ Π΄ΠΎ ΡΡΠΆΠ΅Π»ΠΎΠ³ΠΎ ΡΠ΅ΠΏΡΠΈΡΠ°, ΡΠ΅ΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΎΠΊΠ° ΠΈ ΡΠΌΠ΅ΡΡΠΈ. ΠΠ°ΡΠ΅ΡΠΈΠ°Π» ΠΈ ΠΌΠ΅ΡΠΎΠ΄Ρ. Π Π΅ΡΡΠΎΡΠΏΠ΅ΠΊΡΠΈΠ²Π½ΠΎΠ΅ ΠΎΠ±ΡΠ΅ΡΠ²Π°ΡΠΈΠΎΠ½Π½ΠΎΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ Π±ΡΠ»ΠΎ Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΎ Π½Π° Π²ΡΠ±ΠΎΡΠΊΠ΅ Π² 100 Π²Π·ΡΠΎΡΠ»ΡΡ
ΡΠ΅Π»ΠΎΠ²Π΅ΠΊ, ΠΏΠΎΡΡΡΠΏΠΈΠ²ΡΠΈΡ
Π² Π½Π΅ΠΎΡΠ»ΠΎΠΆΠ½ΠΎΠ΅ ΠΎΡΠ΄Π΅Π»Π΅Π½ΠΈΠ΅ Ρ ΠΏΡΠΈΠ·Π½Π°ΠΊΠ°ΠΌΠΈ ΡΠΈΡΡΠ΅ΠΌΠ½ΠΎΠ³ΠΎ Π²ΠΎΡΠΏΠ°Π»Π΅Π½ΠΈΡ Π΄Π²ΡΡ
Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΡΡ
ΡΡΠΈΠΎΠ»ΠΎΠ³ΠΈΠΉ: ΡΡΠΆΠ΅Π»ΡΠΉ ΠΎΡΡΡΡΠΉ ΠΏΠ°Π½ΠΊΡΠ΅Π°ΡΠΈΡ (ΠΏΡΠ΅Π΄ΠΏΠΎΠ»Π°Π³Π°Π΅ΠΌΡΠΉ, Π° Π·Π°ΡΠ΅ΠΌ ΠΏΠΎΠ΄ΡΠ²Π΅ΡΠΆΠ΄Π΅Π½Π½ΡΠΉ Π² ΠΎΡΠ΄Π΅Π»Π΅Π½ΠΈΠΈ ΡΠ΅Π°Π½ΠΈΠΌΠ°ΡΠΈΠΈ ΠΈ/ΠΈΠ»ΠΈ ΠΎΠΏΠ΅ΡΠ°ΡΠΈΠΎΠ½Π½ΠΎΠΉ) ΠΈΠ»ΠΈ ΠΎΠ±ΡΠΈΠΉ ΠΏΠ΅ΡΠΈΡΠΎΠ½ΠΈΡ. ΠΡΠΎΠΈΠ·Π²ΠΎΠ΄ΠΈΠ»ΠΈ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΡ Π€ΠΠ-a Π² ΠΊΡΠΎΠ²ΠΈ ΡΡΠ°Π·Ρ ΠΏΠΎΡΠ»Π΅ ΠΏΠΎΡΡΡΠΏΠ»Π΅Π½ΠΈΡ. Π€ΠΠ-a ΠΈΠ·ΠΌΠ΅ΡΡΠ»ΠΈ ΠΊΠΎΠΌΠΌΠ΅ΡΡΠ΅ΡΠΊΠΈ Π΄ΠΎΡΡΡΠΏΠ½ΡΠΌ ELISA-ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ Π² ΠΏΠ»Π°Π·ΠΌΠ΅ ΠΊΡΠΎΠ²ΠΈ. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ. Π‘ΡΠ΅Π΄Π½ΠΈΠ΅ ΡΡΠΎΠ²Π½ΠΈ Π€ΠΠ-a ΠΏΡΠΈ ΠΏΠΎΡΡΡΠΏΠ»Π΅Π½ΠΈΠΈ (Π΄Π΅Π½Ρ 0, Π² Π½Π΅ΠΎΡΠ»ΠΎΠΆΠ½ΠΎΠΌ ΠΎΡΠ΄Π΅Π»Π΅Π½ΠΈΠΈ) Π±ΡΠ»ΠΈ Π² 191,5 ΡΠ°Π· Π½ΠΈΠΆΠ΅ Π² Π³ΡΡΠΏΠΏΠ΅ Ρ ΡΠ΅ΠΏΡΠΈΡΠ΅ΡΠΊΠΈΠΌ ΡΠΎΠΊΠΎΠΌ ΠΏΠΎ ΡΡΠ°Π²Π½Π΅Π½ΠΈΡ Ρ Π³ΡΡΠΏΠΏΠΎΠΉ ΡΡΠΆΠ΅Π»ΠΎΠ³ΠΎ ΡΠ΅ΠΏΡΠΈΡΠ° ΠΈ Π² 63 ΡΠ°Π·Π° Π²ΡΡΠ΅ Ρ Π²ΡΠΆΠΈΠ²ΡΠΈΡ
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Two-dimensional superconductivity at a Mott-Insulator/Band-Insulator interface: LaTiO3/SrTiO3
Transition metal oxides display a great variety of quantum electronic
behaviours where correlations often play an important role. The achievement of
high quality epitaxial interfaces involving such materials gives a unique
opportunity to engineer artificial structures where new electronic orders take
place. One of the most striking result in this area is the recent observation
of a two-dimensional electron gas at the interface between a strongly
correlated Mott insulator LaTiO3 and a band insulator SrTiO3. The mechanism
responsible for such a behaviour is still under debate. In particular, the
influence of the nature of the insulator has to be clarified. Here we show that
despite the expected electronic correlations, LaTiO3/SrTiO3 heterostructures
undergo a superconducting transition at a critical temperature Tc=300 mK. We
have found that the superconducting electron gas is confined over a typical
thickness of 12 nm. We discuss the electronic properties of this system and
review the possible scenarios
How a spin-glass remembers. Memory and rejuvenation from intermittency data: an analysis of temperature shifts
The memory and rejuvenation aspects of intermittent heat transport are
explored theoretically and by numerical simulation for Ising spin glasses with
short-ranged interactions. The theoretical part develops a picture of
non-equilibrium glassy dynamics recently introduced by the authors. Invoking
the concept of marginal stability, this theory links irreversible
`intermittent' events, or `quakes' to thermal fluctuations of record magnitude.
The pivotal idea is that the largest energy barrier surmounted prior
to by thermal fluctuations at temperature determines the rate of the intermittent events occurring near . The idea leads
to a rate of intermittent events after a negative temperature shift given by
, where the `effective age' has
an algebraic dependence on , whose exponent contains the temperatures
before and after the shift. The analytical expression is verified by numerical
simulations. Marginal stability suggests that a positive temperature shift could erase the memory of the barrier . The simulations show
that the barrier controls the intermittent dynamics,
whose rate is hence .
Additional `rejuvenation' effects are also identified in the intermittency
data for shifts of both signs.Comment: Revised introduction and discussion. Final version to appear in
Journal of Statistical Mechanics: Theory and Experimen
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