Correlations of Rydberg excitations in an ultra-cold gas after an echo sequence

We show that Rydberg states in an ultra-cold gas can be excited with strongly preferred nearest-neighbor distance if densities are well below saturation. The scheme makes use of an echo sequence in which the first half of a laser pulse excites Rydberg states while the second half returns atoms to the ground state, as in the experiment of Raitzsch et al. [Phys. Rev. Lett. 100 (2008) 013002]. Near to the end of the echo sequence, almost any remaining Rydberg atom is separated from its next-neighbor Rydberg atom by a distance slightly larger than the instantaneous blockade radius half-way through the pulse. These correlations lead to large deviations of the atom counting statistics from a Poissonian distribution. Our results are based on the exact quantum evolution of samples with small numbers of atoms. We finally demonstrate the utility of the omega-expansion for the approximate description of correlation dynamics through an echo sequence.Comment: 8 pages, 6 figure

Long-range potentials and (n−1)d+ns(n-1)d+ns molecular resonances in an ultracold rydberg gas

We have calculated long-range molecular potentials of the $0_g^{+}$, $0_u^{-}$ and $1_u$ symmetries between highly-excited rubidium atoms. Strong $np+np$ potentials characterized by these symmetries are important in describing interaction-induced phenomena in the excitation spectra of high $np$ Rydberg states. Long-range molecular resonances are such phenomena and they were first reported in S.M. Farooqi {\it et al.}, Phys. Rev. Lett. {\bf 91} 183002. One class of these resonances occurs at energies corresponding to excited atom pairs $(n-1)d+ns$. Such resonances are attributed to $\ell$-mixing due to Rydberg-Rydberg interactions so that otherwise forbidden molecular transitions become allowed. We calculate molecular potentials in Hund's case (c), use them to find the resonance lineshape and compare to experimental results.Comment: 11 pages, 7 figure

The Assessment of Breeding Value of First Farrowed Sows by the Method of Selection Indices

The goal of this research paper was to assess the breeding value of first farrowed Swedish Landrace sows by the means of selection indices method. The traits on the basis of which the breeding value of animals was assessed are following: daily liveweight gain, average thickness of collected back fat measured at five sites and number of liveborn piglets in the first litter. The liveweight gain and carcass quality traits determined at the end of performance test were corrected for the body mass of 100kg by the method of basic indexes and following mean values were determined: for corrected daily liveweight gain (KZDP) 499.92g/day and for corrected average collected backfat thickness (KSL) 20.01mm. The first farrowed sows on average produced 8.09 liveborn piglets in the litter. Studying the effect of the gilts` birth year and season on KZDP and KSL it was determined that the gilts` birth year and season had no statistically significant influence (P>0.05) on KZDP variation but they had a statistically significant effect on KSL (P0.05) on BZPL, while the KZDP class and the age at first farrowing had a statistically significant effect on the variability of these trait (P<0.05; P<0.01). All studied traits varied statistically significantly (P<0.01) under the impact of the gilts` sire or dam. Heritability coefficients were: h2= 0.402 for KZDP, h2= 0.261 for KSL and h2= 0.177 for BZPL. The relation between KZDP and KSL was of a medium strength both at phenotype and genetic levels (rph=0.491; rg=0.411), while the relation of these traits with BZPL did not exist, except for the genetic relationship between KSL and KZDP which was of a medium strength (rg=0.252). Three equations for the selection indexes were constructed among which as the most optimal was chosen the one which includes all three traits (KZDP, KSL and BZPL) and whose correlation coefficent of selection index and aggregate genotype was rIAG = 0.5473

Review of eating disorders and oxytocin receptor polymorphisms.

BACKGROUND AND AIMS: Oxytocin, a nine amino acid peptide synthesised in the hypothalamus, has been widely recognised for its role in anxiolysis, bonding, sociality, and appetite. It binds to the oxytocin receptor (OXTR)-a G-protein coupled receptor-that is stimulated by the actions of oestrogen both peripherally and centrally. Studies have implicated OXTR genotypes in conferring either a risk or protective effect in autism, schizophrenia, and eating disorders (ED). There are numerous DNA variations of this receptor, with the most common DNA variation being in the form of the single nucleotide polymorphisms (SNPs). Two OXTR SNPs have been most studied in relation to ED: rs53576 and rs2254298. Each SNP has the same allelic variant that produces genotypes AA, AG, and GG. In this critical review we will evaluate the putative role of rs53576 and rs2254298 SNPs in ED. Additionally, this narrative review will consider the role of gene-environment interactions in the development of ED pathology. FINDINGS: The OXTR SNPs rs53576 and rs2254298 show independent associations between the A allele and restrictive eating behaviours. Conversely, the G allele of the OXTR rs53576 SNP is associated with binging behaviours, findings that were also evident in neuroanatomy. One study found the A allele of both OXTR SNPs to confer risk for more severe ED symptomatology while the G allele conferred some protective effect. An interaction between poor maternal care and rs2254298 AG/AA genotype conferred increased risk for binge eating and purging in women. CONCLUSIONS: Individual OXTR SNP are unlikely in themselves to explain complex eating disorders but may affect the expression of and/or effectiveness of the OXTR. A growing body of G x E work is indicating that rs53576G homozygosity becomes disadvantageous for later mental health under early adverse conditions but further research to extend these findings to eating pathology is needed. The GWAS approach would benefit this area of knowledge

Rydberg trimers and excited dimers bound by internal quantum reflection

Quantum reflection is a pure wave phenomena that predicts reflection of a particle at a changing potential for cases where complete transmission occurs classically. For a chemical bond, we find that this effect can lead to non-classical vibrational turning points and bound states at extremely large interatomic distances. Only recently has the existence of such ultralong-range Rydberg molecules been demonstrated experimentally. Here, we identify a broad range of molecular lines, most of which are shown to originate from two different novel sources: a single-photon associated triatomic molecule formed by a Rydberg atom and two ground state atoms and a series of excited dimer states that are bound by a so far unexplored mechanism based on internal quantum reflection at a steep potential drop. The properties of the Rydberg molecules identified in this work qualify them as prototypes for a new type of chemistry at ultracold temperatures.Comment: 6 pages, 3 figures, 1 tabl

Spirometry reference equations for central European populations from school age to old age.

Spirometry reference values are important for the interpretation of spirometry results. Reference values should be updated regularly, derived from a population as similar to the population for which they are to be used and span across all ages. Such spirometry reference equations are currently lacking for central European populations. To develop spirometry reference equations for central European populations between 8 and 90 years of age. We used data collected between January 1993 and December 2010 from a central European population. The data was modelled using "Generalized Additive Models for Location, Scale and Shape" (GAMLSS). The spirometry reference equations were derived from 118'891 individuals consisting of 60'624 (51%) females and 58'267 (49%) males. Altogether, there were 18'211 (15.3%) children under the age of 18 years. We developed spirometry reference equations for a central European population between 8 and 90 years of age that can be implemented in a wide range of clinical settings

Implementation of prognostic machine learning algorithms in paediatric chronic respiratory conditions: a scoping review.

Machine learning (ML) holds great potential for predicting clinical outcomes in heterogeneous chronic respiratory diseases (CRD) affecting children, where timely individualised treatments offer opportunities for health optimisation. This paper identifies rate-limiting steps in ML prediction model development that impair clinical translation and discusses regulatory, clinical and ethical considerations for ML implementation. A scoping review of ML prediction models in paediatric CRDs was undertaken using the PRISMA extension scoping review guidelines. From 1209 results, 25 articles published between 2013 and 2021 were evaluated for features of a good clinical prediction model using the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) guidelines.Most of the studies were in asthma (80%), with few in cystic fibrosis (12%), bronchiolitis (4%) and childhood wheeze (4%). There were inconsistencies in model reporting and studies were limited by a lack of validation, and absence of equations or code for replication. Clinician involvement during ML model development is essential and diversity, equity and inclusion should be assessed at each step of the ML pipeline to ensure algorithms do not promote or amplify health disparities among marginalised groups. As ML prediction studies become more frequent, it is important that models are rigorously developed using published guidelines and take account of regulatory frameworks which depend on model complexity, patient safety, accountability and liability

Mucosal Vaccination with a Self-Adjuvanted Lipopeptide Is Immunogenic and Protective against Mycobacterium tuberculosis

Tuberculosis (TB) remains a staggering burden on global public health. Novel preventative tools are desperately needed to reach the targets of the WHO post-2015 End-TB Strategy. Peptide or protein-based subunit vaccines offer potential as safe and effective generators of protection, and enhancement of local pulmonary immunity may be achieved by mucosal delivery. We describe the synthesis of a novel subunit vaccine via native chemical ligation. Two immunogenic epitopes, ESAT61−20 and TB10.43−11 from Mycobacterium tuberculosis (Mtb), were covalently conjugated to the TLR2-ligand Pam2Cys to generate a self-adjuvanting lipopeptide vaccine. When administered mucosally to mice, the vaccine enhanced pulmonary immunogenicity, inducing strong Th17 responses in the lungs and multifunctional peripheral T-lymphocytes. Mucosal, but not peripheral vaccination, provided substantial protection against Mtb infection, emphasizing the importance of delivery route for optimal efficacy.NHMR

Observation of coherent many-body Rabi oscillations

A two-level quantum system coherently driven by a resonant electromagnetic field oscillates sinusoidally between the two levels at frequency $\Omega$ which is proportional to the field amplitude [1]. This phenomenon, known as the Rabi oscillation, has been at the heart of atomic, molecular and optical physics since the seminal work of its namesake and coauthors [2]. Notably, Rabi oscillations in isolated single atoms or dilute gases form the basis for metrological applications such as atomic clocks and precision measurements of physical constants [3]. Both inhomogeneous distribution of coupling strength to the field and interactions between individual atoms reduce the visibility of the oscillation and may even suppress it completely. A remarkable transformation takes place in the limit where only a single excitation can be present in the sample due to either initial conditions or atomic interactions: there arises a collective, many-body Rabi oscillation at a frequency $N^0.5\Omega$ involving all N >> 1 atoms in the sample [4]. This is true even for inhomogeneous atom-field coupling distributions, where single-atom Rabi oscillations may be invisible. When one of the two levels is a strongly interacting Rydberg level, many-body Rabi oscillations emerge as a consequence of the Rydberg excitation blockade. Lukin and coauthors outlined an approach to quantum information processing based on this effect [5]. Here we report initial observations of coherent many-body Rabi oscillations between the ground level and a Rydberg level using several hundred cold rubidium atoms. The strongly pronounced oscillations indicate a nearly complete excitation blockade of the entire mesoscopic ensemble by a single excited atom. The results pave the way towards quantum computation and simulation using ensembles of atoms