585 research outputs found
Serbia's Action against Transnational Organised Crime
This article examines the extent to which Serbia has implemented relevant international standards on action against transnational organised crime contained in the United Nations Convention against Transnational Organised Crime 2000. The first part explores key obligations with particular reference to prohibition of substantive offences, intelligence-led law enforcement (special investigative techniques), confiscation of criminal proceeds, as well as international law enforcement cooperation. The second part of the article analyses how these obligations are implemented by Serbia in reality by examining legislative frameworks as well as law enforcement practices. The main conclusion is that, while Serbia has taken some steps to implement international standards with a view to enhancing individual and collective actions against transnational organised crime, effective law enforcement is hampered by issues such as corruption and a lack of expertise, experience and resources
In-situ Investigation of the Early Stage of TiO2 epitaxy on (001) SrTiO3
We report on a systematic study of the growth of epitaxial TiO2 films
deposited by pulsed laser deposition on Ti-terminated (001) SrTiO3 single
crystals. By using in-situ reflection high energy electron diffraction, low
energy electron diffraction, x-ray photoemission spectroscopy and scanning
probe microscopy, we show that the stabilization of the anatase (001) phase is
preceded by the growth of a pseudomorphic Sr-Ti-O intermediate layer, with a
thickness between 2 and 4 nm. The data demonstrate that the formation of this
phase is related to the activation of long range Sr migration from the
substrate to the film. The role of interface Gibbs energy minimization, as a
driving force for Sr diffusion, is discussed. Our results enrich the phase
diagram of the Sr-Ti-O system under epitaxial strain opening the roudeficient
SrTiO phase.Comment: 8 pages, 7 figure
Estimation of the Variance Components of the Sow Litter Size Traits Using Reml Method - Repeatability Model
Variance components for sow litter size traits were estimated using the REML method. Number of live born piglets (NBA), number of still born piglets (NSB), number of total born piglets (NTB) and number of weaned piglets (NW) were treated as traits which repeated several times during sow lifetime - repeatability model. Results of the fertility of Swedish Landrace sows realized on three pig farms in the Republic of Serbia were presented in four data sets DS1 (farm 1), DS2 (farm 2), DS3 (farm 3) and DS23 (farms 2 and 3 together). Fixed part of the model for litter size traits at farrowing (NBA, NSB and NTB) included parity, mating season as year-month interaction, litter genotype and weaning to conception interval as class effects. The age at farrowing was modelled as a quadratic regression nested within parity, whereas preceding lactation length was included as linear regression. In case of NW the model included parity, weaning season as year-month interaction, number of piglets in litter subsequent to crossfostering and litter genotype as class effects. The age at farrowing was included into the model in the same way as in case of previous traits. Random part of the model was the same for all analysed traits and represented as effect of common environment in litter where sows had been born, permanent effect of environment in sows’ litters and direct additive genetic effect. Heritability of NBA varied between 0.050 (DS2) and 0.076 (DS3), NSB between 0.004 (DS3) and 0.027 (DS2), NTB between 0.065 (DS2) and 0.073 (DS3) and of NW between 0.010 (DS2) and 0.028 (DS1). Share of permanent environment of sow in phenotypic variance was higher than share of litter effect and mostly lower than share of direct genetic effect
Observation of Weyl nodes in robust type-II Weyl semimetal WP2
Distinct to type-I Weyl semimetals (WSMs) that host quasiparticles described
by the Weyl equation, the energy dispersion of quasiparticles in type-II WSMs
violates Lorentz invariance and the Weyl cones in the momentum space are
tilted. Since it was proposed that type-II Weyl fermions could emerge from
(W,Mo)Te2 and (W,Mo)P2 families of materials, a large numbers of experiments
have been dedicated to unveil the possible manifestation of type-II WSM, e.g.
the surface-state Fermi arcs. However, the interpretations of the experimental
results are very controversial. Here, using angle-resolved photoemission
spectroscopy supported by the first-principles calculations, we probe the
tilted Weyl cone bands in the bulk electronic structure of WP2 directly, which
are at the origin of Fermi arcs at the surfaces and transport properties
related to the chiral anomaly in type-II WSMs. Our results ascertain that due
to the spin-orbit coupling the Weyl nodes originate from the splitting of
4-fold degenerate band-crossing points with Chern numbers C = 2 induced by
the crystal symmetries of WP2, which is unique among all the discovered WSMs.
Our finding also provides a guiding line to observe the chiral anomaly which
could manifest in novel transport properties.Comment: 13 pages, 3 figure
Evolution from a nodeless gap to d(x2-y2) form in underdoped La(2-x)SrxCuO4
Using angle-resolved photoemission (ARPES), it is revealed that the
low-energy electronic excitation spectra of highly underdoped superconducting
and non-superconducting La(2-x)SrxCuO4 cuprates are gapped along the entire
underlying Fermi surface at low temperatures. We show how the gap function
evolves to a d(x2-y2) form as increasing temperature or doping, consistent with
the vast majority of ARPES studies of cuprates. Our results provide essential
information for uncovering the symmetry of the order parameter(s) in strongly
underdoped cuprates, which is a prerequisite for understanding the pairing
mechanism and how superconductivity emerges from a Mott insulator.Comment: 5 pages, 4 figure
Bulk electronic structure of superconducting LaRu2P2 single crystals measured by soft x-ray angle-resolved photoemission spectroscopy
We present a soft X-ray angle-resolved photoemission spectroscopy (SX-ARPES)
study of the stoichiometric pnictide superconductor LaRu2P2. The observed
electronic structure is in good agreement with density functional theory (DFT)
calculations. However, it is significantly different from its counterpart in
high-temperature superconducting Fe-pnictides. In particular the bandwidth
renormalization present in the Fe-pnictides (~2 - 3) is negligible in LaRu2P2
even though the mass enhancement is similar in both systems. Our results
suggest that the superconductivity in LaRu2P2 has a different origin with
respect to the iron pnictides. Finally we demonstrate that the increased
probing depth of SX-ARPES, compared to the widely used ultraviolet ARPES, is
essential in determining the bulk electronic structure in the experiment.Comment: 4 pages, 4 figures, 1 supplemental material. Accepted for publication
in Physical Review Letter
Charge density waves enhance the electronic noise of manganites
The transport and noise properties of Pr_{0.7}Ca_{0.3}MnO_{3} epitaxial thin
films in the temperature range from room temperature to 160 K are reported. It
is shown that both the broadband 1/f noise properties and the dependence of
resistance on electric field are consistent with the idea of a collective
electrical transport, as in the classical model of sliding charge density
waves. On the other hand, the observations cannot be reconciled with standard
models of charge ordering and charge melting. Methodologically, it is proposed
to consider noise-spectra analysis as a unique tool for the identification of
the transport mechanism in such highly correlated systems. On the basis of the
results, the electrical transport is envisaged as one of the most effective
ways to understand the nature of the insulating, charge-modulated ground states
in manganites.Comment: 6 two-column pages, 5 figure
Exotic Kondo crossover in a wide temperature region in the topological Kondo insulator SmB6 revealed by high-resolution ARPES
Temperature dependence of the electronic structure of SmB6 is studied by
high-resolution ARPES down to 1 K. We demonstrate that there is no essential
difference for the dispersions of the surface states below and above the
resistivity saturating anomaly (~ 3.5 K). Quantitative analyses of the surface
states indicate that the quasi-particle scattering rate increases linearly as a
function of temperature and binding energy, which differs from Fermi-Liquid
behavior. Most intriguingly, we observe that the hybridization between the d
and f states builds gradually over a wide temperature region (30 K < T < 110
K). The surface states appear when the hybridization starts to develop. Our
detailed temperature-dependence results give a complete interpretation of the
exotic resistivity result of SmB6, as well as the discrepancies among
experimental results concerning the temperature regions in which the
topological surface states emerge and the Kondo gap opens, and give new
insights into the exotic Kondo crossover and its relationship with the
topological surface states in the topological Kondo insulator SmB6.Comment: 8 pages, 5 figure
Trivial topological phase of CaAgP and the topological nodal-line transition in CaAg(P1-xAsx)
By performing angle-resolved photoemission spectroscopy and first-principles
calculations, we address the topological phase of CaAgP and investigate the
topological phase transition in CaAg(P1-xAsx). We reveal that in CaAgP, the
bulk band gap and surface states with a large bandwidth are topologically
trivial, in agreement with hybrid density functional theory calculations. The
calculations also indicate that application of "negative" hydrostatic pressure
can transform trivial semiconducting CaAgP into an ideal topological nodal-line
semimetal phase. The topological transition can be realized by partial
isovalent P/As substitution at x = 0.38.Comment: 20 pages, 4 figure
Atomically precise lateral modulation of a two-dimensional electron liquid in anatase TiO2 thin films
Engineering the electronic band structure of two-dimensional electron liquids
(2DELs) confined at the surface or interface of transition metal oxides is key
to unlocking their full potential. Here we describe a new approach to tailoring
the electronic structure of an oxide surface 2DEL demonstrating the lateral
modulation of electronic states with atomic scale precision on an unprecedented
length scale comparable to the Fermi wavelength. To this end, we use pulsed
laser deposition to grow anatase TiO2 films terminated by a (1 x 4) in-plane
surface reconstruction. Employing photo-stimulated chemical surface doping we
induce 2DELs with tunable carrier densities that are confined within a few TiO2
layers below the surface. Subsequent in-situ angle resolved photoemission
experiments demonstrate that the (1 x 4) surface reconstruction provides a
periodic lateral perturbation of the electron liquid. This causes strong
backfolding of the electronic bands, opening of unidirectional gaps and a
saddle point singularity in the density of states near the chemical potential
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