Pre-operative rehabilitation in lower-limb amputation patients and its effect on post-operative outcomes

Major lower-limb amputation (LLA) is a life-changing event associated with poor post-operative physical and psychological functioning and decreased quality of life. The general physical condition of most LLA patients prior to surgery is already significantly deteriorated due to chronic peripheral vascular disease often in combination with diabetes. Pre-operative rehabilitation (also called `pre-rehabilitation') is an increasingly common strategy used in multiple patient populations to improve patients' physical and mental condition prior to surgery, thus aiming at improving the post-operative patient outcomes. Given the positive effects of post-surgical outcomes in many patient populations, we hypothesize that pre-operative rehabilitation will improve post-operative outcomes after LLA. To test this hypothesis, a literature search of PubMed, EMBASE, EBSCOhost, Web of Science and ScienceDirect was performed to identify studies that investigated the impact of a pre-operative rehabilitation therapy on post-operative outcomes such as length of hospital stay, mobility, physical functioning, and health related quality of life. No time restrictions were applied to the search. Only articles published in English were included in the selection. Two studies satisfied the eligibility criteria for inclusion in the review, one qualitative and one quantitative study. The quantitative study reported a beneficial effect of pre-rehabilitation, resulting in post-operative mobility (at least indoor ambulation) in 63% of the included LLA patients. There is a need for prospective clinical studies examining the effect of pre-rehabilitation on post-operative outcomes to be able to confirm or reject our hypothesis. Although the hypothesis seems plausible, evidence is lacking to support our hypothesis that pre-operative rehabilitation will improve post-operative outcomes in patients with LLA. The qualitative study indicated that integrating pre-rehabilitation in the care for LLA patients seems to be limited to a selected group of dysvascular patients, but at this stage cannot be advised based on current evidence even in this subgroup. Further research is needed to clarify whether such an intervention prior to amputation would be a useful and effective tool for optimizing post-operative outcomes in LLA patients

Connecting species’ geographical distributions to environmental variables: range maps versus observed points of occurrence

Connecting the geographical occurrence of a species with underlying environmental variables is fundamental for many analyses of life history evolution and for modeling species distributions for both basic and practical ends. However, raw distributional information comes principally in two forms: points of occurrence (specific geographical coordinates where a species has been observed), and expert-prepared range maps. Each form has potential short-comings: range maps tend to overestimate the true occurrence of a species, whereas occurrence points (because of their frequent non-random spatial distribution) tend to underestimate it. Whereas previous comparisons of the two forms have focused on how they may differ when estimating species richness, less attention has been paid to the extent to which the two forms actually differ in their representation of a species’ environmental associations. We assess such differences using the globally distributed avian order Galliformes (294 species). For each species we overlaid range maps obtained from IUCN and point-of-occurrence data obtained from GBIF on global maps of four climate variables and elevation. Over all species, the median difference in distribution centroids was 234 km, and median values of all five environmental variables were highly correlated, although there were a few species outliers for each variable. We also acquired species’ elevational distribution mid-points (mid-point between minimum and maximum elevational extent) from the literature; median elevations from point occurrences and ranges were consistently lower (median −420 m) than mid-points. We concluded that in most cases occurrence points were likely to produce better estimates of underlying environmental variables than range maps, although differences were often slight. We also concluded that elevational range mid-points were biased high, and that elevation distributions based on either points or range maps provided better estimates

Adiabatically changing the phase-space density of a trapped Bose gas

We show that the degeneracy parameter of a trapped Bose gas can be changed adiabatically in a reversible way, both in the Boltzmann regime and in the degenerate Bose regime. We have performed measurements on spin-polarized atomic hydrogen in the Boltzmann regime demonstrating reversible changes of the degeneracy parameter (phase-space density) by more than a factor of two. This result is in perfect agreement with theory. By extending our theoretical analysis to the quantum degenerate regime we predict that, starting close enough to the Bose-Einstein phase transition, one can cross the transition by an adiabatic change of the trap shape.Comment: 4 pages, 3 figures, Latex, submitted to PR

Cycling in people with a lower limb amputation

BACKGROUND: To evaluate cycling participation and identify barriers and facilitators related to cycling participation in people with a lower limb amputation (LLA) in the Netherlands. METHODS: A questionnaire was sent to adults with a LLA between March and August 2019 to obtain information regarding prosthesis, individual’s characteristics, amputation, cycling barriers and facilitators, and prosthetic satisfaction. The questionnaires were distributed via 8 orthopedic workshops, post and were given directly. To find cycling predictors, variables associated with cycling (p < 0.1) were entered into a logistic regression analysis. Non-significant variables were removed manually. RESULTS: Participants (n = 207, 71% males) had a mean age of 62.0 ± 13.0 years. The most frequent level of amputation was transtibial (42%), and trauma was the most frequent cause of amputation (43%). After the LLA, 141 participants (68%) cycled for recreation (80%), physical fitness (74%), and transport (50%). In the past six months, cyclists cycled for recreation (79%) and transport (66%). Most cycled less than once a day. Recreational cyclists cycled alone (75%) for a median duration of 45 min or 14 km per ride. Cyclists with a transportation purpose usually cycled to go shopping (80%) or to visit friends (68%), with a median duration of 20 min or five kilometers per ride. Cyclists reported more facilitators (median (IQR) = 5 (3, 7) than non-cyclists 0 (0, 3). The majority of cyclists reported a positive attitude toward cycling (89%) and cycled because of health benefits (81%). A dynamic foot (odds ratio: 5.2, 95% CI 2.0, 13.3) and a higher number of facilitators (odds ratio: 1.3, 95% CI 1.2, 1.5) positively predicted cycling, whereas the presence of other underlying diseases (odds ratio: 0.4, 95% CI 0.2, 0.9) negatively predicted cycling (R(2): 40.2%). CONCLUSION: In the Netherlands, the majority of adults cycled after a LLA, mainly for recreational purposes. A dynamic foot, a higher number of facilitators, and no other underlying diseases increases the likelihood of cycling after a LLA. The results suggest that personal motivation and a higher mobility level could be the key to increasing cycling participation. Future research should determine the association between motivation, mobility levels, and cycling with a LLA. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13102-021-00302-3

Finite-lattice expansion for Ising models on quasiperiodic tilings

Low-temperature series are calculated for the free energy, magnetisation, susceptibility and field-derivatives of the susceptibility in the Ising model on the quasiperiodic Penrose lattice. The series are computed to order 20 and estimates of the critical exponents alpha, beta and gamma are obtained from Pade approximants.Comment: 16 pages, REVTeX, 26 postscript figure

Genetic diversity, population structure, and genetic correlation with climatic variation in chickpea (Cicer arietinum) landraces from Pakistan

Chickpea (Cicer arietinum L.) production in arid regions, such as those predominant in Pakistan, faces immense challenges of drought and heat stress. Addressing these challenges is made more difficult by the lack of genetic and phenotypic characterization of available cultivated varieties and breeding materials. Genotyping-by-sequencing offers a rapid and cost-effective means to identify genome-wide nucleotide variation in crop germplasm. When combined with extended crop phenotypes deduced from climatic variation at sites of collection, the data can predict which portions of genetic variation might have roles in climate resilience. Here we use 8113 single nucleotide polymorphism markers to determine genetic variation and compare population structure within a previously uncharacterized collection of 77 landraces and 5 elite cultivars, currently grown in situ on farms throughout the chickpea growing regions of Pakistan. The compiled landraces span a striking aridity gradient into the Thal Desert of the Punjab. Despite low levels of variation across the collection and limited genetic structure, we found some differentiation between accessions from arid, semiarid, irrigated, and coastal areas. In a subset of 232 markers, we found evidence of differentiation along gradients of elevation and isothermality. Our results highlight the utility of exploring large germplasm collections for nucleotide variation associated with environmental extremes, and the use of such data to nominate germplasm accessions with the potential to improve crop drought tolerance and other environmental traits

Competition and coexistence of bond and charge orders in (TMTTF)2AsF6

(TMTTF)2AsF6 undergoes two phase transitions upon cooling from 300 K. At Tco=103 K a charge-ordering (CO) occurs, and at Tsp(B=9 T)=11 K the material undergoes a spin-Peierls (SP) transition. Within the intermediate, CO phase, the charge disproportionation ratio is found to be at least 3:1 from carbon-13 NMR 1/T1 measurements on spin-labeled samples. Above Tsp, up to about 3Tsp, 1/T1 is independent of temperature, indicative of low-dimensional magnetic correlations. With the application of about 0.15 GPa pressure, Tsp increases substantially, while Tco is rapidly suppressed, demonstrating that the two orders are competing. The experiments are compared to results obtained from calculations on the 1D extended Peierls-Hubbard model.Comment: 4 pages, 5 figure

Atomic Deuterium Adsorbed on the Surface of Liquid Helium

We investigate deuterium atoms adsorbed on the surface of liquid helium in equilibrium with a vapor of atoms of the same species. These atoms are studied by a sensitive optical method based on spectroscopy at a wavelength of 122 nm, exciting the 1S-2P transition. We present a direct measurement of the adsorption energy of deuterium atoms on helium and show evidence for the existence of resonantly enhanced recombination of atoms residing on the surface to molecules.Comment: 6 pages 4 figure