Ultracold Atoms as a Target: Absolute Scattering Cross-Section Measurements

We report on a new experimental platform for the measurement of absolute scattering cross-sections. The target atoms are trapped in an optical dipole trap and are exposed to an incident particle beam. The exponential decay of the atom number directly yields the absolute total scattering cross-section. The technique can be applied to any atomic or molecular species that can be prepared in an optical dipole trap and provides a large variety of possible scattering scenarios

Performance Limitations of Flat Histogram Methods and Optimality of Wang-Landau Sampling

We determine the optimal scaling of local-update flat-histogram methods with system size by using a perfect flat-histogram scheme based on the exact density of states of 2D Ising models.The typical tunneling time needed to sample the entire bandwidth does not scale with the number of spins N as the minimal N^2 of an unbiased random walk in energy space. While the scaling is power law for the ferromagnetic and fully frustrated Ising model, for the +/- J nearest-neighbor spin glass the distribution of tunneling times is governed by a fat-tailed Frechet extremal value distribution that obeys exponential scaling. We find that the Wang-Landau algorithm shows the same scaling as the perfect scheme and is thus optimal.Comment: 5 pages, 6 figure

All-optical formation of a Bose-Einstein condensate for applications in scanning electron microscopy

We report on the production of a F=1 spinor condensate of 87Rb atoms in a single beam optical dipole trap formed by a focused CO2 laser. The condensate is produced 13mm below the tip of a scanning electron microscope employing standard all-optical techniques. The condensate fraction contains up to 100,000 atoms and we achieve a duty cycle of less than 10s.Comment: 5 pages, 4 figure

Manifestation of the bulk phase transition in the edge energy spectrum in a two dimensional bilayer electron system

We use a quasi-Corbino sample geometry with independent contacts to different edge states in the quantum Hall effect regime to investigate the edge energy spectrum of a bilayer electron system at total filling factor $\nu=2$. By analyzing non-linear $I-V$ curves in normal and tilted magnetic fields we conclude that the edge energy spectrum is in a close connection with the bulk one. At the bulk phase transition spin-singlet - canted antiferromagnetic phase $I-V$ curve becomes to be linear, indicating the disappearance or strong narrowing of the $\nu=1$ incompressible strip at the edge of the sample.Comment: 5 pages, 5 figure

Coronary artery disease-associated genetic variants and biomarkers of inflammation

Introduction: Genetic constitution and inflammation both contribute to development of coronary artery disease (CAD). Several CAD-associated single-nucleotide polymorphisms (SNPs) have recently been identified, but their functions are largely unknown. We investigated the associations between CAD-associated SNPs and five CAD-related inflammatory biomarkers. Methods: We genotyped 45 CAD-associated SNPs in 701 stable CAD patients in whom levels of high-sensitivity C-reactive protein (hsRCP), interleukin-6, calprotectin, fibrinogen and complement component 3 levels had previously been measured. A genetic risk score was calculated to assess the combined risk associated with all the genetic variants. A multiple linear regression model was used to assess associations between the genetic risk score, single SNPs, and the five inflammatory biomarkers. Results: The minor allele (G) (CAD risk allele) of rs2075650 (TOMM40/APOE) was associated with lower levels of high-sensitivity C-reactive protein (effect per risk allele: -0.37 mg/l [95%CI -0.56 to -0.18 mg/l]). The inflammatory markers tested showed no association with the remaining 44 SNPs or with the genetic risk score. Conclusions: In stable CAD patients, the risk allele of a common CAD-associated marker at the TOMM40/APOE locus was associated with lower hsCRP levels. No other genetic variants or the combined effect of all variants were associated with the five inflammatory biomarkers

Role of phason-defects on the conductance of a 1-d quasicrystal

We have studied the influence of a particular kind of phason-defect on the Landauer resistance of a Fibonacci chain. Depending on parameters, we sometimes find the resistance to decrease upon introduction of defect or temperature, a behavior that also appears in real quasicrystalline materials. We demonstrate essential differences between a standard tight-binding model and a full continuous model. In the continuous case, we study the conductance in relation to the underlying chaotic map and its invariant. Close to conducting points, where the invariant vanishes, and in the majority of cases studied, the resistance is found to decrease upon introduction of a defect. Subtle interference effects between a sudden phason-change in the structure and the phase of the wavefunction are also found, and these give rise to resistive behaviors that produce exceedingly simple and regular patterns.Comment: 12 pages, special macros jnl.tex,reforder.tex, eqnorder.tex. arXiv admin note: original tex thoroughly broken, figures missing. Modified so that tex compiles, original renamed .tex.orig in source

Separately contacted edge states: A new spectroscopic tool for the investigation of the quantum Hall effect

Using an innovative combination of a quasi-Corbino sample geometry and the cross-gate technique, we have developed a method that enables us to separately contact single edge channels in the quantum Hall regime and investigate equilibration among them. Performing 4-point resistance measurements, we directly obtain information on the energetic and geometric structure of the edge region and the equilibration-length for current transport across the Landau- as well as the spin-gap. Based on an almost free choice in the number of participating edge channels and their interaction-length a systematic investigation of the parameter-space becomes possible.Comment: 8 pages, 7 figure

Ukupna taložna tvar na području Primorsko-goranske županije u razdoblju 1975.-2008.

Dustfall measurements in Primorsko-goranska county started in 1975 in the Bakar Bay (Site 2 - Bakar and Site 3 - Kraljevica). The measurements were extended to the city of Rijeka (Site 1 - Rijeka) in 1982, to the nearby islands (Site 4 - Krk and Site 5 - Cres) in 1986, and inland to Gorski Kotar (Site 6 - Delnice and Site 7 - Lividraga) in 1995. This article brings the results of dustfall measurements from 1975 to 2008. Dustfall was low in the city, the nearby islands, and Gorski Kotar. Recommended and limit values were occasionally exceeded in the Bakar Bay due to emissions from the coke plant and harbour at Site 2 (1979-1997) and from the shipyard at Site 3. Lead content in the dustfall was below the national limits, save for two occasions at Site 2. Deposition of sulphur and nitrogen at the inland sites were below the respective critical load values.Ispitivanja ukupne taložne tvari u Primorsko-goranskoj županiji započela su 1975. godine na području Bakarskog zaljeva. Mjerenja su se 1982. god proširila na grad Rijeku, 1986. na otoke Krk i Cres, a 1995. i na područje Gorskog kotara. U radu su prikazani rezultati mjerenja ukupne taložne tvari u razdoblju 1975.-2008. na sedam odabranih postaja: u gradu Rijeci, dvije na području Bakarskog zaljeva (Bakar i Kraljevica), dvije na otocima (Krk i Cres) te dvije u Gorskom kotaru (Delnice i Lividraga). Analizirano je kretanje prosječnih godišnjih vrijednosti ukupno istaloženih tvari te u njima prisutnih količina sagorivog pepela, sulfata, nitrata, amonija i olova. Na području grada Rijeke, otoka Krka i Cresa te Gorskog kotara količina ukupne taložne tvari je niska. Količine ukupne taložne tvari povremeno su prelazile preporučenu graničnu vrijednost u Bakru (1979.-1994.), zbog emisija iz koksare i iz luke za rasuti teret te u Kraljevici, gdje se osamdesetih godina osjećao utjecaj koksare u Bakru, a od sredine devedesetih pojačani rad u brodogradilištu. Količine olova u taložnoj tvari su niske na svim postajama, osim povremenih skokova u Bakru, kada su prijeđene preporučene vrijednosti. Količine istaloženog sumpora i dušika na području Gorskog kotara ispod su odgovarajućih vrijednosti kritičnog opterećenja za ispitivana područja

Elevated serum alpha-1 antitrypsin is a major component of GlycA-associated risk for future morbidity and mortality

Background GlycA is a nuclear magnetic resonance (NMR) spectroscopy biomarker that predicts risk of disease from myriad causes. It is heterogeneous; arising from five circulating glycoproteins with dynamic concentrations: alpha-1 antitrypsin (AAT), alpha-1-acid glycoprotein (AGP), haptoglobin (HP), transferrin (TF), and alpha-1-antichymotrypsin (AACT). The contributions of each glycoprotein to the disease and mortality risks predicted by GlycA remain unknown. Methods We trained imputation models for AAT, AGP, HP, and TF from NMR metabolite measurements in 626 adults from a population cohort with matched NMR and immunoassay data. Levels of AAT, AGP, and HP were estimated in 11,861 adults from two population cohorts with eight years of follow-up, then each biomarker was tested for association with all common endpoints. Whole blood gene expression data was used to identify cellular processes associated with elevated AAT. Results Accurate imputation models were obtained for AAT, AGP, and HP but not for TF. While AGP had the strongest correlation with GlycA, our analysis revealed variation in imputed AAT levels was the most predictive of morbidity and mortality for the widest range of diseases over the eight year follow-up period, including heart failure (meta-analysis hazard ratio = 1.60 per standard deviation increase of AAT, P-value = 1×10−10), influenza and pneumonia (HR = 1.37, P = 6×10−10), and liver diseases (HR = 1.81, P = 1×10−6). Transcriptional analyses revealed association of elevated AAT with diverse inflammatory immune pathways. Conclusions This study clarifies the molecular underpinnings of the GlycA biomarker’s associated disease risk, and indicates a previously unrecognised association between elevated AAT and severe disease onset and mortality.Peer reviewe