Unstable regimes for a Bose-Einstein condensate in an optical lattice

We report on the experimental characterization of energetic and dynamical instability, two mechanisms responsible for the breakdown of Bloch waves in a Bose-Einstein condensate interacting with a 1D optical lattice. A clear separation of these two regimes is obtained performing measurements at different temperatures of the atomic sample. The timescales of the two processes have been determined by measuring the losses induced in the condensate. A simple phenomenological model is introduced for energetic instability while a full comparison is made between the experiment and the 3D Gross-Pitaevskii theory that accounts for dynamical instability

Observation of dynamical instability for a Bose-Einstein condensate in a moving 1D optical lattice

We have experimentally studied the unstable dynamics of a harmonically trapped Bose-Einstein condensate loaded into a 1D moving optical lattice. The lifetime of the condensate in such a potential exhibits a dramatic dependence on the quasimomentum state. This is unambiguously attributed to the onset of dynamical instability, after a comparison with the predictions of the Gross-Pitaevskii theory. Deeply in the unstable region we observe the rapid appearance of complex structures in the atomic density profile, as a consequence of the condensate phase uniformity breakdown

Habitual Activity in Pre-industrial Rural and Urban Dutch Populations: A Study of Lower Limb Cross-sectional Geometry

This study combines historical data and the principles of bone functional adaptation to examine variation in terrestrial mobility in men and women from pre-industrial urban (Alkmaar 7M, 9F) and rural (Klaaskinderkerke 12M, 8F; Middenbeemster 21M, 22F) Dutch populations. Cross-sectional properties of the femoral and tibial midshaft are determined to investigate variation in lower limb mechanical loading. All populations had comparable age ranges. Rural Middenbeemster males had significantly more elliptically shaped tibiae compared to the other populations. Rural males from Klaaskinderkerke had significantly greater femoral cross-sectional area and torsional rigidity compared to females. In the tibia, the males from both rural populations had greater torsional rigidity and cross-sectional area compared to females. In the rural Middenbeemster population the males also had significantly more elliptically shaped tibiae compared to females. While no sexual dimorphism was found in the urban Alkmaar, significantly greater variation in lower limb cross-sectional properties was found for both males and females relative to the rural populations. These results conform to predictions based on the historical literature of greater lower limb loading in rural males compared to females as well as a greater variety of tasks performed in urban environments. The lack of significant differences in lower limb torsional rigidity or shape between populations in either sex suggests that rural life was not necessarily more physically strenuous than urban life in pre-industrial Dutch populations. However, variation in sexual dimorphism suggests that labor between males and females was differently organized in the rural and urban samples.BioarchaeologyRoman Provinces, Middle Ages and Modern Perio

Computer-aided recording of automatic endoscope washing and disinfection processes as an integral part of medical documentation for quality assurance purposes

<p>Abstract</p> <p>Background</p> <p>The reprocessing of medical endoscopes is carried out using automatic cleaning and disinfection machines. The documentation and archiving of records of properly conducted reprocessing procedures is the last and increasingly important part of the reprocessing cycle for flexible endoscopes.</p> <p>Methods</p> <p>This report describes a new computer program designed to monitor and document the automatic reprocessing of flexible endoscopes and accessories in fully automatic washer-disinfectors; it does not contain nor compensate the manual cleaning step. The program implements national standards for the monitoring of hygiene in flexible endoscopes and the guidelines for the reprocessing of medical products. No FDA approval has been obtained up to now. The advantages of this newly developed computer program are firstly that it simplifies the documentation procedures of medical endoscopes and that it could be used universally with any washer-disinfector and that it is independent of the various interfaces and software products provided by the individual suppliers of washer-disinfectors.</p> <p>Results</p> <p>The computer program presented here has been tested on a total of four washer-disinfectors in more than 6000 medical examinations within 9 months.</p> <p>Conclusions</p> <p>We present for the first time an electronic documentation system for automated washer-disinfectors for medical devices e.g. flexible endoscopes which can be used on any washer-disinfectors that documents the procedures involved in the automatic cleaning process and can be easily connected to most hospital documentation systems.</p

One-dimensional phase transitions in a two-dimensional optical lattice

A phase transition for bosonic atoms in a two-dimensional anisotropic optical lattice is considered. If the tunnelling rates in two directions are different, the system can undergo a transition between a two-dimensional superfluid and a one-dimensional Mott insulating array of strongly coupled tubes. The connection to other lattice models is exploited in order to better understand the phase transition. Critical properties are obtained using quantum Monte Carlo calculations. These critical properties are related to correlation properties of the bosons and a criterion for commensurate filling is established.Comment: 14 pages, 8 figure

The talar morphology of a hypochondroplasic dwarf: A case study from the Italian Late Antique period

This project aims to test whether geometric morphometric (GM) and trabecular analyses may be useful tools in identifying talar characteristics related to hypochondroplasia. We quantified the external and internal talar morphology of a hypochondroplasic dwarf (T17) from Modena (northern Italy) dated to the sixth century AD. External talar morphology of T17 was compared with a broad sample of modern human tali (n = 159) using GM methods. Additionally, a subsample of these tali (n = 41) was used to investigate whole talar trabecular changes in T17. Our results show that GM and trabecular analyses identify a combination of traits linked to the dwarfing disorder of hypochondroplasia. These traits include decreased scaled talar dimensions compared with normal-sized individuals, presence of an accessory antero-lateral talar facet, high bone volume fraction, and high anisotropy values throughout the entire talus. In our case study, hypochondroplasia does not appear to substantially modify external talar morphology probably due to the fast growth of the talus. We suggest that small talar dimensions are associated with hypochondroplasia. An antero-lateral talar facet may result from the talus and calcaneus coalition (i.e., talocalcaneal abnormal bridging) possibly related to an everted foot posture that was limited by overgrowth of the fibula. We suggest that high talar trabecular density and strut orientation provide insights into pathological development of the trabecular plates in T17. Finally, our study suggests that high talar trabecular density and strut orientation, and small talar dimensions, may be added as possible concomitant talar hallmarks for hypochondroplasia

Metacarpal trabecular bone varies with distinct hand-positions used in hominid locomotion

Trabecular bone remodels during life in response to loading and thus should, at least in part, reflect potential variation in the magnitude, frequency and direction of joint loading across different hominid species. Here we analyse the trabecular structure across all non-pollical metacarpal distal heads (Mc2-5) in extant great apes, expanding on previous volume of interest and whole-epiphysis analyses that have largely focussed on only the first or third metacarpal. Specifically, we employ both a univariate statistical mapping and a multivariate approach to test for both inter-ray and interspecific differences in relative trabecular bone volume fraction (RBV/TV) and degree of anisotropy (DA) in Mc2-5 subchondral trabecular bone. Results demonstrate that while DA values only separate Pongo from African apes (Pan troglodytes, Pan paniscus, Gorilla gorilla), RBV/TV distribution varies with the predicted loading of the metacarpophalangeal (McP) joints during locomotor behaviours in each species. Gorilla exhibits a relatively dorsal distribution of RBV/TV consistent with habitual hyper-extension of the McP joints during knuckle-walking, whereas Pongo has a palmar distribution consistent with flexed McP joints used to grasp arboreal substrates. Both Pan species possess a disto-dorsal distribution of RBV/TV, compatible with multiple hand postures associated with a more varied locomotor regime. Further inter-ray comparisons reveal RBV/TV patterns consistent with varied knuckle-walking postures in Pan species in contrast to higher RBV/TV values toward the midline of the hand in Mc2 and Mc5 of Gorilla, consistent with habitual palm-back knuckle-walking. These patterns of trabecular bone distribution and structure reflect different behavioural signals that could be useful for determining the behaviours of fossil hominins

Systemic patterns of trabecular bone across the human and chimpanzee skeleton

Aspects of trabecular bone architecture are thought to reflect regional loading of the skeleton, and thus differ between primate taxa with different locomotor and postural modes. However, there are several systemic factors that affect bone structure that could contribute to, or be the primary factor determining, interspecific differences in bone structure. These systemic factors include differences in genetic regulation, sensitivity to loading, hormone levels, diet, and/or activity levels. Improved understanding of inter/intraspecific variability, and variability across the skeleton of an individual, is required to properly interpret potential functional signals present within trabecular structure. Using a whole-region method of analysis, we investigated trabecular structure throughout the skeleton of humans and chimpanzees. Trabecular bone volume fraction (BV/TV), degree of anisotropy (DA) and trabecular thickness (Tb.Th) were quantified from high resolution micro-computed tomographic scans of the humeral and femoral head, third metacarpal and third metatarsal head, distal tibia, talus and first thoracic vertebra. We find that BV/TV is, in most anatomical sites, significantly higher in chimpanzees than in humans, suggesting a systemic difference in trabecular structure unrelated to local loading regime. Differences in BV/TV between the forelimb and hindlimb do not clearly reflect differences in locomotor loading in the study taxa. There are no clear systemic differences between the taxa in DA and, as such, this parameter may reflect function and relate to differences in joint loading. This systemic approach reveals both the pattern of variability across the skeleton and between taxa, and helps identify those features of trabecular structure that may relate to joint function