Extended Bose-Hubbard model with dipolar excitons.

The Hubbard model constitutes one of the most celebrated theoretical frameworks of condensed-matter physics. It describes strongly correlated phases of interacting quantum particles confined in lattice potentials1,2. For bosons, the Hubbard Hamiltonian has been deeply scrutinized for short-range on-site interactions3-6. However, accessing longer-range couplings has remained elusive experimentally7. This marks the frontier towards the extended Bose-Hubbard Hamiltonian, which enables insulating ordered phases at fractional lattice fillings8-12. Here we implement this Hamiltonian by confining semiconductor dipolar excitons in an artificial two-dimensional square lattice. Strong dipolar repulsions between nearest-neighbour lattice sites then stabilize an insulating state at half filling. This characteristic feature of the extended Bose-Hubbard model exhibits the signatures theoretically expected for a chequerboard spatial order. Our work thus highlights that dipolar excitons enable controlled implementations of boson-like arrays with strong off-site interactions, in lattices with programmable geometries and more than 100 sites.

Clinical implications of high-sensitivity cardiac troponins.

Cardiac troponin assays have become more sensitive over the years leading to the clinical introduction of high-sensitivity cardiac troponin assays in 2010. Their use has revolutionized the assessment of patients with chest pain in the emergency department by allowing earlier rule-in and rule-out of myocardial infarction leading to shorter stays in the emergency department and reduced admissions for chest pain. The incidence of myocardial infarction has increased slightly, and patients with myocardial infarction diagnosed with high-sensitivity cardiac troponins have been found to have a reduced risk of reinfarction, though without an impact on survival. High-sensitivity cardiac troponins are powerful predictors of long-term mortality and cardiovascular disease in the general population as well as in patients with chest pain with or without cardiovascular disease. The increase in risk for death and cardiovascular disease associated with high-sensitivity cardiac troponins is graded and starts already at detectable levels, well below the upper normal level. The aim of this review was to describe the clinical use and consequences of the introduction of high-sensitivity cardiac troponins. In addition, the importance of persistently elevated troponin levels for prognosis and what investigations may be appropriate to perform in patients with stable troponin elevations are discussed.

The use of a Swedish telephone medical advice service by the elderly - a population-based study.

OBJECTIVE: The present study aimed to describe contact made by the elderly to Sweden's nationwide medical helpline, Healthcare Guide 1177 by Phone (HGP). Other objectives were to study potential gender differences and the association between different HGP referral levels and acute visits to hospital-based emergency departments and acute visits to primary care centres. DESIGN: De-identified data from recorded calls to HGP was extracted for analysis (n = 7477 for the oldest age group). Information about acute visits to emergency departments and to primary care reception was extracted from the patient administration system. SETTING: Västerbotten County, Sweden. SUBJECTS: Patients over 80 years. MAIN OUTCOME MEASURES: Calling and visiting frequencies for different age groups as well as reasons for contact and individual recommendations. RESULTS: The utilisation rate of the telephone advice service for the oldest age group was high, with an incidence rate of 533 per 1000 person-years. Women had a 1.17 times higher incidence rate compared with men. The most common reason for contact was drug-related questions (17% of all contacts). Calls that were recommended to care by a medical specialist correlated with total emergency department visits (r = 0.30, p < 0.05) and calls that were given advice correlated with acute primary healthcare visits (r = 0.38, p = 0.005). CONCLUSION: The high utilisation of the telephone advice service by the elderly gives the telephone advice service a unique ability to function as a gatekeeper to further healthcare. Our data suggest that with the telephone advice service's present guidelines, a significant proportion of all calls are being directed to further medical help. The high frequency of drug-related questions raises concerns about the elderly's medication regimens. Key points Patients over 80 years of age had a high utilisation of the telephone medical advice service compared with other age groups. Drug-related questions were the most common reason for contact. A significant proportion of all calls made resulted in further heatlhcare contacts.

Low fructosamine and mortality - A long term follow-up of 215,011 non-diabetic subjects in the Swedish AMORIS study.

BACKGROUND AND AIMS: Both high and low fasting glucose has been associated with an increased mortality among individuals without diabetes. This J-shaped association has also been shown for HbA1c in relation to all-cause mortality. High fructosamine is associated with increased mortality. In this study we aim to evaluate if low fructosamine is also associated with increased mortality in non-diabetic subjects. METHODS AND RESULTS: We included 215,011 subjects from the AMORIS cohort undergoing occupational health screening or primary care in Stockholm, Sweden. Cause specific mortality was obtained from the Swedish Cause-of-Death Register by record linkage. Hazard ratios for the lowest decile of fructosamine were estimated by Cox regression for all-cause (n = 41,388 deaths) and cause-specific mortality during 25 years of follow-up. We observed gradually increased mortality with lower fructosamine in a large segment of the population. In the lowest decile of fructosamine the sex, age, social class and calendar adjusted hazard ratio was 1.20 (95% CI; 1.18-1.27) compared to deciles 2-9. This increased mortality was attenuated after adjustment for six other biomarkers (HR = 1.11 (95% CI; 1.07-1.15)). Haptoglobin, an indicator of chronic inflammation, made the greatest difference in the point estimate. In sensitivity analyses we found an association between low fructosamine and smoking and adjustment for smoking further attenuated the association between low fructosamine and mortality. CONCLUSION: Low levels of fructosamine in individuals without diabetes were found to be associated with increased mortality. Smoking and chronic inflammation seem to at least partially explain this association but an independent contribution by low fructosamine cannot be excluded.

Selective zircon accumulation in a new benthic foraminifer, Psammophaga zirconia, sp. nov.

Benthic foraminifera are single-celled eukaryotes that make a protective organic, agglutinated or calcareous test. Some agglutinated, single-chambered taxa, including Psammophaga Arnold, 1982, retain mineral particles in their cytoplasm, but the selective mechanism of accumulation is not clear. Here, we report the ability of a foraminiferal species to select and accumulate zircons and other heavy minerals in their cytoplasm. In particular, the use of Scanning Electron Microscope coupled with an Energy Dispersive X-ray microanalysis system (SEM-EDS) enabled a representative overview of the mineral diversity and showed that the analysed Psammophaga zirconia sp. nov. individuals contained dominantly crystals of zircon (51%), titanium oxides (27%), and ilmenite (11%) along with minor magnetite and other minerals. The studied specimens occur in the shallow central Adriatic Sea where the sediment has a content of zircon below 1% and of other heavy minerals below 4%. For that reason we hypothesize that: (i) P. zirconia may be able to chemically select minerals, specifically zircon and rutile; (ii) the chemical mechanism allowing the selection is based on electrostatic interaction, and it could work also for agglutinated foraminifera (whether for ingestion, like Xenophyophores, or incorporation in the test as in many other described taxa). In particular, this aptitude for high preferential uptake and differential ingestion or retention of zircon is reported here for the first time, together with the selection of other heavy minerals already described in members of the genus Psammophaga. They are generally counted among early foraminifera, constructing a morphologically simple test with a single chamber. Our molecular phylogenetic study confirms that P. zirconia is a new species, genetically distinctive from other Psammophaga, and occurs in the Adriatic as well as in the Black Sea.

Observation of the Berezinskii-Kosterlitz-Thouless Phase Transition in an Ultracold Fermi Gas.

We experimentally investigate the first-order correlation function of a trapped Fermi gas in the two-dimensional BEC-BCS crossover. We observe a transition to a low-temperature superfluid phase with algebraically decaying correlations. We show that the spatial coherence of the entire trapped system can be characterized by a single temperature-dependent exponent. We find the exponent at the transition to be constant over a wide range of interaction strengths across the crossover. This suggests that the phase transitions in both the bosonic regime and the strongly interacting crossover regime are of Berezinskii-Kosterlitz-Thouless type and lie within the same universality class. On the bosonic side of the crossover, our data are well described by the quantum Monte Carlo calculations for a Bose gas. In contrast, in the strongly interacting regime, we observe a superfluid phase which is significantly influenced by the fermionic nature of the constituent particles.

Hartree-Fock ground state phase diagram of jellium.

We calculate the ground state phase diagram of the homogeneous electron gas in three dimensions within the Hartree-Fock approximation and show that broken symmetry states are energetically favored at any density against the homogeneous Fermi gas state with isotropic Fermi surface. At high density, we find metallic spin-unpolarized solutions where electronic charge and spin density form an incommensurate crystal having more crystal sites than electrons. For r(s)→0, our solutions approach pure spin-density waves, whereas the commensurate Wigner crystal is favored at lower densities, r(s)≳3.4. Decreasing the density, the system undergoes several structural phase transitions with different lattice symmetries. The polarization transition occurs around r(s)≈8.5.

Electrical readout of individual nuclear spin trajectories in a single-molecule magnet spin transistor.

We present the electrical readout of time trajectories obtained from an isolated nuclear spin. The device, a TbPc(2) single-molecule magnet spin transistor, detects the four different nuclear spin states of the Tb(3+) ion with fidelities better than 69%, allowing us to measure individual relaxation times (T(1)) of several tens of seconds. A good agreement with quantum Monte Carlo simulations suggests that the relaxation times are limited by the current tunneling through the transistor, which opens up the possibility to tune T(1) electrically by means of bias and gate voltages.

Lactate production as a response to intrapartum hypoxia in the growth-restricted fetus.

OBJECTIVE: To analyse whether the increase in lactate in response to intrapartum hypoxia differs between small- (SGA), appropriate- (AGA) and large-for-gestational-age (LGA) fetuses. DESIGN: Observational cohort study. SETTING: Ten obstetric units in Sweden. POPULATION: A cohort of 1496 women. METHODS: A secondary analysis of a randomised controlled trial, in which 1496 women with fetal heart rate abnormalities, indicating fetal scalp blood sampling, were randomised to lactate analyses. After delivery, the neonates were divided according to birthweight for gestational age into SGA, AGA and LGA groups. MAIN OUTCOME MEASURE: Lactate concentration in fetal scalp blood. SECONDARY OUTCOME MEASURES: Acid-base balance in cord artery blood and Apgar score <7 at 5 minutes. RESULTS: Median lactate concentrations in the SGA, AGA and LGA groups were 3.8, 3.0 and 2.2 mmol/l, respectively (SGA versus AGA, P = 0.017; LGA versus AGA, P = 0.009). In the subgroups with scalp lactate >4.8 mmol/l (lactacidaemia), the corresponding median (range) values were 6.2 (4.9-14.6), 5.9 (4.9-15.9) and 5.7 mmol/l (5.0-7.9 mmol/l), respectively (no significant differences between the groups). The proportions of neonates with cord artery pH < 7.00, metabolic acidaemia or Apgar score <7 at 5 minutes were similar in all weight groups. CONCLUSION: SGA fetuses with fetal heart rate abnormalities have the same ability to produce lactate as a response to intrapartum hypoxia as AGA and LGA fetuses. The risk of a poor outcome associated with high lactate concentration is the same in SGA, AGA and LGA fetuses. Scalp blood lactate analysis is therefore a reliable method for intrapartum fetal surveillance of suspected growth-restricted fetuses scheduled for vaginal delivery at ≥ 34 weeks of gestation.

Renal function assessed by two different formulas and incidence of myocardial infarction and death in middle-aged men and women.

BACKGROUND: Chronic kidney disease predicts mortality in the general population, but less is known about the association with incidence of first myocardial infarction. We evaluated glomerular filtration rates (GFR) estimated by the Modification of Diet in Renal Disease study (GFR-MDRD) equation and the Mayo formula (GFR-Mayo) as predictors of myocardial infarction and death. METHODS: In 571 353 Swedish men and women, undergoing health controls, with mean age 45 years, and no previous myocardial infarction, hazard ratios were calculated to assess the association between renal function and incidence of myocardial infarction and all-cause mortality, respectively. Glomerular filtration rate 60-90, 30-60 and <30 mL per minute per 1.73 m(2), was defined as mildly, moderately and severely decreased GFR, respectively. RESULTS: There were 19 510 myocardial infarctions and 56 367 deaths during 11.6 years of follow-up. Hazard ratios (and 95% confidence intervals) for myocardial infarction, using GFR-Mayo were 1.11 (1.06-1.16) for mildly, 1.32 (1.18-1.48) for moderately and 2.54 (1.90-3.40) for severely decreased GFR. The corresponding figures for GFR-MDRD were 1.01 (0.96-1.05), 1.23 (1.14-1.32) and 2.49 (1.85-3.35). Mortality was increased at all levels of reduced GFR-Mayo and at moderately or severely decreased GFR-MDRD. CONCLUSIONS: Already mildly decreased GFR increase the risk of myocardial infarction and death in the general population. The association with adverse outcomes is stronger when GFR-Mayo rather than GFR-MDRD is used to assess renal function.

Backflow correlations for the electron gas and metallic hydrogen.

We justify and evaluate backflow three-body wave functions for a two-component system of electrons and protons. Based on the generalized Feynman-Kacs formula, many-body perturbation theory, and band structure calculations, we analyze the use and the analytical form of the backflow function from different points of view. The resulting wave functions are used in variational and diffusion Monte Carlo calculations of the electron gas and of solid and liquid metallic hydrogen. For the electron gas, the purely analytic backflow and three-body form gives lower energies than those of previous calculations. For bcc hydrogen, analytical and optimized backflow-three-body wave functions lead to energies nearly as low as those from using local density approximation orbitals in the trial wave function. However, compared to wave functions constructed from density functional solutions, backflow wave functions have the advantage of only few parameters to estimate, the ability to include easily and accurately electron-electron correlations, and that they can be directly generalized from the crystal to a disordered liquid of protons.

[Relation of breast cancer tumour stage and the degree of registration in a population-based cancer registry]. / Abhängigkeit der Tumorstadien von der Vollzähligkeit der Registrierung bei Brustkrebs in einem bevölkerungsbezogenen Krebsregister.

UNLABELLED: Population-based cancer registries provide a large database of cancer cases which can be used for evaluation of cancer epidemiological and care-related questions. In particular, the latest projects in breast cancer screening and quality assured breast cancer diagnostics represent appropriate databases in the use of cancer registry data for further evaluation. For breast cancer the tumour stage distribution is a well suited, early available indicator for evaluating such interventions. The problem in using data from cancer registries occurs with the rather long time period until registration can be completed (up to 3 years). Thus, early usage of cancer registry data remains rather questionable. AIM OF THE STUDY: This analysis aims to show whether the distribution of breast cancer tumour stage depends on the completeness of registration and whether a valid estimate of the tumour stage distribution is possible at an early stage, on the basis of a not fully completed registration. METHODS: The cancer registry records all new cancer cases of the Federal State of Schleswig-Holstein. For the period from 1998 to the beginning of 2003 all breast cancer cases and their tumour stage distribution were extracted at three-month' intervals. Completeness of registration for each date was estimated on the basis of cancer data from the Federal State of Saarland. The expected number of breast cancer cases for Schleswig-Holstein was set to 100%. RESULTS: In total, 7,418 patients with new breast cancer were analysed. Already at a degree of 50% of registration a stable distribution of tumour stage could be observed. For example, the variability of the T1-category (tumour size < or = 2 cm) showed a maximum of three per cent in the range from 50% up to 100% completeness. Also for lymph nodes and distant metastases just a small degree of variability from one to three per cent points could be shown. A 75% completeness of breast cancer registration was established about six months after the end of the year of diagnosis. Complete registration could only be reached significantly later, approximately after two years. CONCLUSION: For the cancer registry of Schleswig-Holstein a significant relation of the tumour stage distribution in the degree of registration could not be detected. A stable distribution could be shown with a completeness of 50-75%. Hence, it appears to be methodically justified to analyse the tumour stage of breast cancer data with sufficient validity with a completeness of 75 %. The tumour stage distribution can be used as an early indicator (about six months after the end of the year of diagnosis) for evaluation of projects like mammography screening, quality management or research on medical care.

Left ventricular diastolic function is related to glucose in a middle-aged population.

OBJECTIVES: To examine the relation between left ventricular (LV) diastolic function and glucose metabolism in individuals without previously diagnosed diabetes mellitus. DESIGN: A cross-sectional population-based study. SETTING: A university hospital. SUBJECTS: Thirty-five men and women 56-58 years of age without previously diagnosed diabetes or heart disease. MAIN OUTCOME MEASURES: Left ventricular diastolic function assessed by pulsed Doppler tissue imaging and its relation to fasting plasma glucose, glucose postload and glycated haemoglobin. LV diastolic function was determined by measuring early diastolic filling peak velocity (Em wave cm s-1), late diastolic filling peak velocity (Am wave cm s-1) and their ratio Em/Am. RESULTS: Peak Em velocity, peak Am velocity and their ratio Em/Am correlated with fasting plasma glucose (r=-0.42, P=0.01; r=0.47, P=0.04 and r=-0.53, P=0.001, respectively). There was a correlation between peak Em velocity, the ratio of Em/Am and glycated haemoglobin. LV diastolic function was also related to glucose postload. CONCLUSIONS: Left ventricular diastolic function is related to concentrations of fasting plasma glucose, glucose postload and glycated haemoglobin even below the threshold of diabetes. This indicates that glucose concentrations already in the upper end of the normal range has negative impact on cardiac function.

Morphological and molecular characterization of a new terrestrial allogromiid species: Edaphoallogromia australica gen. et spec. nov. (Foraminifera) from Northern Queensland (Australia).

The foraminiferal family Allogromiidae occurs mainly in marine environments, although some genera are described from brackish and freshwater habitats. We report here the occurrence of a terrestrial allogromiid foraminiferan. Phylogenetic relationships were investigated by sequencing part of the SSU rDNA. DNA sequence analysis confirms a close relationship of the new species to the genus Allogromia. Morphological studies corroborate the affiliation to the family Allogromiidae but the lack of an entosolenian tube and an internal septum as well as the different ecology do not allow a classification into a known genus of this family. Taking the molecular, morphological and ecological differences into account, a new genus Edaphoallogromia with the type species E. australica is erected.

Nonanalytic dependence of the transition temperature of the homogeneous dilute Bose gas on scattering length.

We show that the shift in the transition temperature of the dilute homogeneous Bose gas is nonanalytic in the scattering amplitude a. The first correction beyond the positive linear shift in a is negative and of order a(2)lna. This nonuniversal nonanalytic structure indicates how the discrepancies between numerical calculations at finite a can be reconciled with calculations of the limit a-->0, since the linearity is apparent only for anomalously small a.

[Thrombosis of mechanical tricuspid valve. Thrombolysis should be considered as a first line approach]. / Trombotiserad mekanisk trikuspidalklaff. Trombolys bör övervägas i första hand.

This report describes a 60-year old man who three years earlier, due to tricuspid endocarditis, had undergone surgery entailing insuturation of a Carbomedic valve prosthesis. He was admitted via the emergency room with clinical signs of right heart failure, and he reported that he had not heard the valve sound for two to three weeks. Cineradiography revealed a dysfunction of the tricuspid valve prosthesis, with the bileaflet tilting disc closed in the opening position. Thrombolytic therapy was successful. We review the literature on obstructed mechanical prosthetic valves and on the use of thrombolysis.

Molecular identification of algal endosymbionts in large miliolid Foraminifera: 2. Dinofiagellates.

Large miliolid foraminifers of the subfamily Soritinae bear symbiotic dinoflagellates morphologically similar to the species of the "Symbiodinium" complex, commonly found in corals and other marine invertebrates. Soritid foraminifers are abundant in coral reefs and it has been proposed that they share their symbionts with other dinoflagellate-bearing reef dwellers. In order to test this hypothesis, we have analysed partial large subunit ribosomal DNA sequences from dinoflagellates symbionts obtained from 28 foraminiferal specimens, and compared them to the corresponding sequences of Symbiodinium-like endosymbionts from various groups of invertebrates. Phylogenetic analysis of our data shows that all soritid symbionts belong to the "Symbiodinium" species complex, within which they form seven different molecular types (Frl-Fr7). Only one of these types (Fr1) branches within a group of invertebrate symbionts, previously described as type C. The remaining six types form sister groups to coral symbionts previously designed as types B, C, and D. Our data indicate a high genetic diversity and specificity of Symbiodinium-like symbionts in soritids. Except for type C, we have found no evidence for the transmission of symbionts between foraminifers and other symbiont-bearing invertebrates from the same localities. However, exchanges must have occurred frequently between the different species of Soritinae, as suggested by the lack of host specificity and some biogeographical patterns observed in symbiont distribution. Our data suggest that members of the subfamily Soritinae acquired their symbionts at least three times during their history, each acquisition being followed by a rapid diversification and independent radiation of symbionts within the foraminiferal hosts.

Molecular identification of algal endosymbionts in large miliolid foraminifera: 1. Chlorophytes.

Large miliolid foraminifers bear various types of algal endosymbionts including chlorophytes, dinoflagellates, rhodophytes, and diatoms. Symbiosis plays a key role in the adaptation of large foraminifera to survival and growth in oligotrophic seas. The identity and diversity of foraminiferal symbionts, however, remain largely unknown. In the present work we use ribosomal DNA (rDNA) sequences to identify chlorophyte endosymbionts in large miliolid foraminifera of the superfamily Soritacea. Partial 18S and complete Internal Transcribed Spacer (ITS) rDNA sequences were obtained from symbionts of eight species representing all genera of extant chlorophyte-bearing Soritacea. Phylogenetic analysis of the sequences confirms the previous fine structure-based identification of these endosymbionts as belonging to the genus Chlamydomonas. All foraminiferal symbionts form a monophyletic group closely related to Chlamydomonas noctigama. The group is composed of seven types identified in this study, including one previously morphologically described species, Chlamydomonas hedleyi. Each of these types can be considered as a separate species, based on the comparison of genetic differences observed between other established Chlamydomonas species. Several foraminiferal species share the same symbiont type, but only one species, Archaias angulatus, was found to bear more than one type.

[Assessment of routine mobility in geriatrics using static posturography--a population based study]. / Die Erfassung alltagsrelevanter Mobilität in der Geriatrie mittels statischer Posturographie--Eine bevölkerungsbezogene Studie.

In a population-based study of 110 women between 53 and 82 years of age (mean age 64.5 +/- 7.9 years) static posturography data were compared to functional items of gait and balance in common geriatric mobility scales. Posturographic data of double-stance with eyes open and eyes closed (DSEO; DSEC) did not differ from those of a group of healthy women previously tested for intact nervous system function. The total neuromuscular score--roughly corresponding to the well-known Tinetti score--did not correlate to the posturographic measures. DSEC correlated with the items "rapid walking" and "single-stance left leg". Age, vision, and neuropsychologic test results correlated with DSEO, "rapid walking", "single-stance right leg", "single-stance left leg", and "walking a figure eight". Multiple linear regression confirmed the impact of age, vision, DSEO, and DSEC on "rapid walking" with a 34% variance explanation. Posturographic parameters did predict other selected gait and balance items. When used in older women living independently in the community, parameters of static posturography reflect to some extent the functional disabilities of gait and balance.

Bose-einstein condensation in quasi-2D trapped gases

We discuss Bose-Einstein condensation (BEC) in quasi-2D trapped gases and find that well below the transition temperature T(c) the equilibrium state is a true condensate, whereas at intermediate temperatures T