Josephson coupling through ferromagnetic heterojunctions with noncollinear magnetizations

We study the Josephson effect in clean heterojunctions that consist of superconductors connected through two metallic ferromagnets with insulating interfaces. We solve the scattering problem based on the Bogoliubov--de Gennes equation for any relative orientation of in-plane magnetizations, arbitrary transparency of interfaces, and mismatch of Fermi wave vectors. Both spin singlet and triplet superconducting correlations are taken into account, and the Josephson current is calculated as a function of the ferromagnetic layers thicknesses and of the angle $\alpha$ between their magnetizations. We find that the critical Josephson current $I_c$ is a monotonic function of $\alpha$ when the junction is far enough from $0-\pi$ transitions. This holds when ferromagnets are relatively weak. For stronger ferromagnets, variation of $\alpha$ induces switching between 0 and $\pi$ states and $I_c(\alpha)$ is non-monotonic function, displaying characteristic dips at the transitions. However, the non-monotonicity is the effect of a weaker influence of the exchange potential in the case of non-parallel magnetizations. No substantial impact of spin-triplet superconducting correlations on the Josephson current has been found in the clean limit. Experimental control of the critical current and $0-\pi$ transitions by varying the angle between magnetizations is suggested.Comment: 7 pages, 8 figure

The Influence of Fatteners Dry and Liquid Diet on Slaughter Traits of Carcass Sides

The study was conducted on 700 fattening pigs, three breed half blood with Duroc as a terminal breed ((Large White x Landrace) x Duroc). The pigs were divided into the two groups according to diet: dry and liquid nutrition. Each group consisted of 350 fattening pigs and used the same feed mixtures in prefattening (CP-3) and fattening (ST). During the period from 24.8 to 60kg they were fed with a CP-3, a crude protein content of 16.37%. During the period from 60kg until the end they were fed with ST, a crude protein content of 15.3%. Muscle tissue processed half-carcasses in slaughterhouses were determined by a device that determines the value of S (fat thickness) and M (muscle thickness) using "method one point." Fat thickness skin in mm, measured 7 cm lateral to the central (median) cutting, in the amount between the second and third ribs of the tail. The thickness of the muscle in mm was measured at the same place as the thickness of the bacon. The results show that the fatling fed dry food had significantly higher carcass weight (80.41: 78.51 kg, p<0.05), backfat thickness (16.55: 15.31 mm, p<0.05), weight (muscle 55.80: 53.82, p<0.05), but a lower percentage of meat (56.6: 57.3, p<0.05) as compared to pigs fed liquid food. In finishing pigs fed dry food, between carcass weight and backfat thickness and muscle thickness a positive and significant correlation (0.4267 and 0.4290, p<0.05) was found and between carcass weight and lean meat a significant negative correlation (-0. 4236 and p<0.05). Between backfat thickness and lean meat in the carcass a negative and significant correlation (-0.8534, p<0.05) was found and between muscle thickness and lean meat a positive and significant correlation (0.2857, p<0.05). In finishing pigs fed liquid food, between carcass weight and backfat thickness and muscle thickness a positive and significant correlation (0.1800 and 0.3705, p<0.05) was found and between carcass weight and lean meat a significant negative correlation (-0. 2178; p <0.05). Between backfat thickness and percentage of meat in the carcass negative and significant correlation (-0.8692, p<0.05) was found and between muscle thickness and lean meat a positive and significant correlation (0.3168, p<0.05)

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

Time-resolved photoluminescence of n-doped SrTiO_3

Following the recent surge of interest in n-doped strontium titanate as a possible blue light emitter, a time-resolved photoluminescence analysis was performed on nominally pure, Nb-doped and oxygen-deficient single-crystal SrTiO3 samples. The doping-effects on both the electronic states involved in the transition and the decay mechanism are respectively analyzed by comparing the spectral and dynamic features and the yields of the emission. Our time-resolved analysis, besides shedding some light on the basic recombination mechanisms acting in these materials, sets the intrinsic bandwidth limit of the proposed blue light emitting optoelectronic devices made of Ti-based perovskites heterostructures in the GHz range

Inhomogeneous superconductivity induced in a weak ferromagnet

Under certain conditions, the order parameter induced by a superconductor (S) in a ferromagnet (F) can be inhomogeneous and oscillating, which results e.g. in the so-called pi-coupling in S/F/S junctions. In principle, the inhomogeneous state can be induced at T_c as function of the F-layer thickness d_F in S/F bilayers and multilayers, which should result in a dip-like characteristic of T_c(d_F). We show the results of measurements on the S/F system Nb/Cu_{1-x}Ni_x, for Ni-concentrations in the range x = 0.5-0.7, where such effects might be expected. We find that the critical thickness for the occurrence of superconductivity is still relatively high, even for these weak ferromagnets. The resulting dip then is intrinsically shallow and difficult to observe, which explains the lack of a clear signature in the T_c(d_F) data.Comment: 4 pages, 4 figures. To be publishedin Physica C (proceedings of the Second Euroconference on Vortex Matter in Superconductors, Crete, 2001

Do you cov me? Effect of coverage reduction on metagenome shotgun sequencing studies

Shotgun metagenomics sequencing is a powerful tool for the characterization of complex biological matrices, enabling analysis of prokaryotic and eukaryotic organisms and viruses in a single experiment, with the possibility of reconstructing de novo the whole metagenome or a set of genes of interest. One of the main factors limiting the use of shotgun metagenomics on wide scale projects is the high cost associated with the approach. We set out to determine if it is possible to use shallow shotgun metagenomics to characterize complex biological matrices while reducing costs. We used a staggered mock community to estimate the optimal threshold for species detection. We measured the variation of several summary statistics simulating a decrease in sequencing depth by randomly subsampling a number of reads. The main statistics that were compared are diversity estimates, species abundance, and ability of reconstructing de novo the metagenome in terms of length and completeness. Our results show that diversity indices of complex prokaryotic, eukaryotic and viral communities can be accurately estimated with 500,000 reads or less, although particularly complex samples may require 1,000,000 reads. On the contrary, any task involving the reconstruction of the metagenome performed poorly, even with the largest simulated subsample (1,000,000 reads). The length of the reconstructed assembly was smaller than the length obtained with the full dataset, and the proportion of conserved genes that were identified in the meta-genome was drastically reduced compared to the full sample. Shallow shotgun metagenomics can be a useful tool to describe the structure of complex matrices, but it is not adequate to reconstruct-even partially-the metagenome

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

Fracture Toughness of Thin Plates by the Double-Torsion Test Method

Double torsion testing can produce fracture toughness values without crack length measurement that are comparable to those measured via standardized techniques such as the chevron-notch, surface-crack-in-flexure and precracked beam if the appropriate geometry is employed, and the material does not exhibit increasing crack growth resistance. Results to date indicate that 8 2 are required if crack length is not considered in stress intensity calculations. At L/W = 2, the normalized crack length should be 0.35 80) nonlinear effects were encountered

Evaluation of Alternative Sources of Supplementary Cementitious Materials (SCMs) for Concrete Materials in Transportation Infrastructure

Fly ash is the most utilized supplementary cementitious material (SCM) in the US. Nonetheless, rapid decline in coal-fired power generation threatens its supply. The objective of this study was to evaluate alternative SCMs for concrete transportation infrastructure in Region 6. SCMs investigated included reclaimed fly ash (RFA), reclaimed ground bottom ash (GBA), metakaolin (MK), and conventional Class F fly ash (FA) as a reference. SCMs were characterized and the fresh and hardened properties of concrete incorporating different dosages (i.e., 10, 20, and 30% cement replacement by mass) of the individual SCMs (i.e., binary systems) and blended SCM systems of RFA-MK and GBA-MK (i.e., ternary systems) were assessed. All the coal ashes met the requirements for pozzolanic component, CaO, SO3, moisture content, LOI, SAI, and water requirement to be classified as Class F pozzolan according to ASTM C618. MK met all the but the water requirement. Concrete using FA generally exhibited better workability than the control mixture (i.e., without SCMs), whereas concrete incorporating RFA, GBA, and MK presented decrements in workability. Mixtures implementing ternary systems also displayed decrements in workability. Air content of fresh concrete mixtures incorporating binary and ternary systems generally decreased. Relative to the control mixture, decrements in 28-day compressive strength (f’c) were reported when incorporating FA and RFA, yet this was generally not the case for the 90-day f’c. In the case of GBA mixtures, significant differences in f’c were not observed after 28 days nor 90 days. MK mixtures as well as RFA-MK and GBA-MK mixtures generally presented increments in 28-day and 90-day f’c. Concrete mixtures implementing coal ashes did not produce significant differences in 28-day surface resistivity (SR) at any cement replacement levels; yet after 90 days of curing, significant improvements in SR were reported. MK, RFA-MK, and GBA-MK mixtures exhibited significant increments in SR at all dosages after 28 and 90 days of curing. Notably, while the control mixture and mixtures incorporating coal ashes did not meet the 28-day SR requirement for class A1 concrete according to LaDOTD, mixtures implementing MK and ternary systems did in almost all cases. All SCMs were effective at reducing drying shrinkage. Binary systems reduced drying shrinkage by 24.2-69.1%, whereas ternary systems reduced drying shrinkage by 55.2-75.3%. With regards ASR, mixtures implementing SCMs presented significantly lower expansion and the increment in SCMs content further reduced the expansion; thus, signaling a positive effect in suppressing ASR related expansion, specially at high dosages

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