The Surface of a Bose-Einstein Condensed Atomic Cloud

We investigate the structure and collective modes of a planar surface of a trapped Bose-Einstein condensed gas at zero temperature. In the long-wavelength limit we find a mode similar to the gravity wave on the surface of a fluid with the frequency $\omega$ and the wavenumber $q$ related by $\omega^2=Fq/m$. Here $F$ is the force due to the confining potential at the surface and $m$ is the particle mass. At shorter wavelengths we use a variational approach and find corrections to $\omega^2$ of order $q^4 \ln{q}$. We demonstrate the usefulness of the concept of an effective surface tension for describing both static and dynamic properties of condensed atomic clouds.Comment: 8 pages, REVTEX, submitted to Phys. Rev.

Ansatz from Non-Linear Optics Applied to Trapped Bose-Einstein Condensates

A simple analytical ansatz, which has been used to describe the intensity profile of the similariton laser (a laser with self-similar propagation of ultrashort pulses), is used as a variational wave function to solve the Gross-Pitaevskii equation for a wide range of interaction parameters. The variational form interpolates between the noninteracting density profile and the strongly interacting Thomas-Fermi profile smoothly. The simple form of the ansatz is modified for both cylindrically symmetric and completely anisotropic harmonic traps. The resulting ground-state density profile and energy are in very good agreement with both the analytical solutions in the limiting cases of interaction and the numerical solutions in the intermediate regime.Comment: 4 pages, 3 figures, published versio

Patients with prostate cancer and androgen deprivation therapy have increased risk of fractures—a study from the Fractures and Fall Injuries in the Elderly Cohort (FRAILCO)

Summary Osteoporosis is a common complication of androgen deprivation therapy (ADT). In this large Swedish cohort study consisting of a total of nearly 180,000 older men, we found that those with prostate cancer and ADT have a significantly increased risk of future osteoporotic fractures. Introduction: Androgen deprivation therapy (ADT) in patients with prostate cancer is associated to increased risk of fractures. In this study, we investigated the relationship between ADT in patients with prostate cancer and the risk of incident fractures and non-skeletal fall injuries both compared to those without ADT and compared to patients without prostate cancer. Methods: We included 179,744 men (79.1 ± 7.9 years (mean ± SD)) from the Swedish registry to which national directories were linked in order to study associations regarding fractures, fall injuries, morbidity, mortality and medications. We identified 159,662 men without prostate cancer, 6954 with prostate cancer and current ADT and 13,128 men with prostate cancer without ADT. During a follow-up of approximately 270,300 patient-years, we identified 10,916 incident fractures including 4860 hip fractures. Results: In multivariable Cox regression analyses and compared to men without prostate cancer, those with prostate cancer and ADT had increased risk of any fracture (HR 95% CI 1.40 (1.28–1.53)), hip fracture (1.38 (1.20–1.58)) and MOF (1.44 (1.28–1.61)) but not of non-skeletal fall injury (1.01 (0.90–1.13)). Patients with prostate cancer without ADT did not have increased risk of any fracture (0.97 (0.90–1.05)), hip fracture (0.95 (0.84–1.07)), MOF (1.01 (0.92–1.12)) and had decreased risk of non-skeletal fall injury (0.84 (0.77–0.92)). Conclusions: Patients with prostate cancer and ADT is a fragile patient group with substantially increased risk of osteoporotic fractures both compared to patients without prostate cancer and compared to those with prostate cancer without ADT. We believe that this must be taken in consideration in all patients with prostate cancer already at the initiation of ADT

Multiply quantized vortices in trapped Bose-Einstein condensates

Vortex configurations in rotating Bose-Einstein condensed gases trapped in power-law and anharmonic potentials are studied. When the confining potential is steeper than harmonic in the plane perpendicular to the axis of rotation, vortices with quantum numbers larger than one are energetically favorable if the interaction is weak enough. Features of the wave function for small and intermediate rotation frequencies are investigated numerically.Comment: 9 pages, 6 figures. Revised and extended article following referee repor

Phase diagram of quantized vortices in a trapped Bose-Einstein condensed gas

We investigate the thermodynamic stability of quantized vortices in a dilute Bose gas confined by a rotating harmonic trap at finite temperature. Interatomic forces play a crucial role in characterizing the resulting phase diagram, especially in the large $N$ Thomas-Fermi regime. We show that the critical temperature for the creation of stable vortices exhibits a maximum as a function of the frequency of the rotating trap and that the corresponding transition is associated with a discontinuity in the number of atoms in the condensate. Possible strategies for approaching the vortical region are discussed.Comment: Revtex, 4 pages, 2 figure

Hip fracture risk and safety with alendronate treatment in the oldest-old

Background. There is high evidence for secondary prevention of fractures, including hip fracture, with alendronate treatment, but alendronate’s efficacy to prevent hip fractures in the oldest-old (≥80 years old), the population with the highest fracture risk, has not been studied. Objective. To investigate whether alendronate treatment amongst the oldest-old with prior fracture was related to decreased hip fracture rate and sustained safety. Methods. Using a national database of men and women undergoing a fall risk assessment at a Swedish healthcare facility, we identified 90 795 patients who were 80 years or older and had a prior fracture. Propensity score matching (four to one) was then used to identify 7844 controls to 1961 alendronate-treated patients. The risk of incident hip fracture was investigated with Cox models and the interaction between age and treatment was investigated using an interaction term. Results. The case and control groups were well balanced in regard to age, sex, anthropometrics and comorbidity. Alendronate treatment was associated with a decreased risk of hip fracture in crude (hazard ratio (HR) 0.62 (0.49–0.79), P < 0.001) and multivariable models (HR 0.66 (0.51–0.86), P < 0.01). Alendronate was related to reduced mortality risk (HR 0.88 (0.82–0.95) but increased risk of mild upper gastrointestinal symptoms (UGI) (HR 1.58 (1.12–2.24). The alendronate association did not change with age for hip fractures or mild UGI. Conclusion. In old patients with prior fracture, alendronate treatment reduces the risk of hip fracture with sustained safety, indicating that this treatment should be considered in these high-risk patient

Association between recurrent fracture risk and implementation of fracture liaison services in four Swedish hospitals: A cohort study

Structured secondary preventions programs, called fracture liaison services (FLSs), increase the rate of evaluation with bone densitometry and use of osteoporosis medication after fracture. However, the evidence regarding the effect on the risk of recurrent fracture is insufficient. The aim of this study was to investigate if implementation of FLS was associated with reduced risk of recurrent fractures. In this retrospective cohort study, electronic health records during 2012 to 2017 were used to identify a total of 21,083 patients from four hospitals in Western Sweden, two with FLS (n = 15,449) and two without (n = 5634). All patients aged 50 years or older (mean age 73.9 [SD 12.4] years, 76% women) with a major osteoporotic index fracture (hip, clinical spine, humerus, radius, and pelvis) were included. The primary outcome was recurrent major osteoporotic fracture. All patients with an index fracture during the FLS period (n = 13,946) were compared with all patients in the period before FLS implementation (n = 7137) in an intention‐to‐treat analysis. Time periods corresponding to the FLS hospitals were used for the non‐FLS hospitals. In the hospitals with FLSs, there were 1247 recurrent fractures during a median follow‐up time of 2.2 years (range 0–6 years). In an unadjusted Cox model, the risk of recurrent fracture was 18% lower in the FLS period compared with the control period (hazard ratio = 0.82, 95% confidence interval [CI] 0.73–0.92, p = .001), corresponding to a 3‐year number needed to screen of 61, and did not change after adjustment for clinical risk factors. In the hospitals without FLSs, no change in recurrent fracture rate was observed. Treatment decisions were made according to the Swedish treatment guidelines. In conclusion, implementation of FLS was associated with a reduced risk of recurrent fracture, indicating that FLSs should be included routinely at hospitals treating fracture patients. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research

Vortices in Bose-Einstein-Condensed Atomic Clouds

The properties of vortex states in a Bose-Einstein condensed cloud of atoms are considered at zero temperature. Using both analytical and numerical methods we solve the time-dependent Gross-Pitaevskii equation for the case when a cloud of atoms containing a vortex is released from a trap. In two dimensions we find the simple result that the time dependence of the cloud radius is given by $(1+\omega^2t^2)^{1/2}$, where $\omega$ is the trap frequency. We calculate and compare the expansion of the vortex core and the cloud radius for different numbers of particles and interaction strengths, in both two and three dimensions, and discuss the circumstances under which vortex states may be observed experimentally.Comment: Revtex, 11 pages including 5 eps figures, submitted to Phys. Rev. A; new reference added, remark added in Sec. IIIB, axis label added in Fig.

Type 2 diabetes and risk of hip fractures and non-skeletal fall injuries in the elderly: A study from the Fractures and Fall Injuries in the Elderly Cohort (FRAILCO)

Questions remain about whether the increased risk of fractures in patients with type 2 diabetes (T2DM) is related mainly to increased risk of falling or to bone‐specific properties. The primary aim of this study was to investigate the risk of hip fractures and non‐skeletal fall injuries in older men and women with and without T2DM. We included 429,313 individuals (aged 80.8 ± 8.2 years [mean ± SD], 58% women) from the Swedish registry “Senior Alert” and linked the data to several nationwide registers. We identified 79,159 individuals with T2DM (45% with insulin [T2DM‐I], 41% with oral antidiabetics [T2DM‐O], and 14% with no antidiabetic treatment [T2DM‐none]) and 343,603 individuals without diabetes. During a follow‐up of approximately 670,000 person‐years, we identified in total 36,132 fractures (15,572 hip fractures) and 20,019 non‐skeletal fall injuries. In multivariable Cox regression models where the reference group was patients without diabetes and the outcome was hip fracture, T2DM‐I was associated with increased risk (adjusted hazard ratio (HR) [95% CI] 1.24 [1.16–1.32]), T2DM‐O with unaffected risk (1.03 [0.97–1.11]), and T2DM‐none with reduced risk (0.88 [0.79–0.98]). Both the diagnosis of T2DM‐I (1.22 [1.16–1.29]) and T2DM‐O (1.12 [1.06–1.18]) but not T2DM‐none (1.07 [0.98–1.16]) predicted non‐skeletal fall injury. The same pattern was found regarding other fractures (any, upper arm, ankle, and major osteoporotic fracture) but not for wrist fracture. Subset analyses revealed that in men, the risk of hip fracture was only increased in those with T2DM‐I, but in women, both the diagnosis of T2DM‐O and T2DM‐I were related to increased hip fracture risk. In conclusion, the risk of fractures differs substantially among patients with T2DM and an increased risk of hip fracture was primarily found in insulin‐treated patients, whereas the risk of non‐skeletal fall injury was consistently increased in T2DM with any diabetes medication. © 2016 American Society for Bone and Mineral Research

Hydrodynamic Approach to Vortex Lifetime in Trapped Bose Condensates

We study a vortex in a two-dimensional, harmonically trapped Bose-Einstein condensate at zero temperature. Through a variational calculation using a trial condensate wave function and a nonlinear Schroedinger Lagrangian, we obtain the effective potential experienced by a vortex at an arbitrary position in the condensate, and find that an off-center vortex will move in a circular trajectory around the trap center. We find the frequency of this precession to be smaller than the elementary excitation frequencies in the cloud. We also study the radiation of sound from a moving vortex in an infinite, uniform system, and discuss the validity of this as an approximation for the trapped case. Furthermore, we estimate the lifetime of a vortex due to imperfections in the trapping potential.Comment: 10 pages, 1 eps figure, submitted to PRA, adjustments in response to referee, one refernce adde