Messianic hope in Isaiah

https://place.asburyseminary.edu/ecommonsatsdissertations/2070/thumbnail.jp

Stability of Bose-Einstein condensates in a Kronig-Penney potential

We study the stability of Bose-Einstein condensates with superfluid currents in a one-dimensional periodic potential. By using the Kronig-Penney model, the condensate and Bogoliubov bands are analytically calculated and the stability of condensates in a periodic potential is discussed. The Landau and dynamical instabilities occur in a Kronig-Penney potential when the quasimomentum of the condensate exceeds certain critical values as in a sinusoidal potential. It is found that the onsets of the Landau and dynamical instabilities coincide with the point where the perfect transmission of low energy excitations through each potential barrier is forbidden. The Landau instability is caused by the excitations with small $q$ and the dynamical instability is caused by the excitations with $q=\pi/a$ at their onsets, where $q$ is the quasimomentum of excitation and $a$ is the lattice constant. A swallow-tail energy loop appears at the edge of the first condensate band when the mean-field energy is sufficiently larger than the strength of the periodic potential. We find that the upper portion of the swallow-tail is always dynamically unstable, but the second Bogoliubov band has a phonon spectrum reflecting the positive effective mass.Comment: 32 pages, 21 figure

Lower-limb alignment and posterior tibial slope in Pakistanis: a radiographic study

Abstract PURPOSE: To assess the lower-limb alignment and posterior tibial slope in Pakistanis. METHODS: 40 male and 19 female healthy Pakistanis aged 20 to 45 years were recruited. A full weight-bearing anteroposterior radiograph of the entire lower limb of each subject was obtained. The axial alignment was measured based on the centres of the femoral head, knee, and ankle. The tibiofemoral (TF) angle, knee joint line obliquity angle (angle J), and posterior tibial slope were determined. RESULTS: The mean TF angle was more varus in men than women (178.4 degrees vs. 180.0 degrees, p\u3c0.001). The mean angle J was more medially inclined in men than women (93.4 degrees vs. 91.4 degrees, p=0.007). The mean medial tibial slope was greater in women than men (16.0 degrees vs. 12.5 degrees, p\u3c0.001). The posterior tibial slope was greater in women than men (14.1 degrees vs. 12.5 degrees, p=0.02), and was greater than the 5 degrees to 10 degrees commonly reported. CONCLUSIONS: Knee alignment and geometry vary in different population subsets. With regard to total knee arthroplasty, the more medially inclined angle J in Pakistani men suggests that an anteroposterior cut of the distal femur should be in increased external rotation, compared with Pakistani women. Whereas the greater posterior tibial slope in Pakistanis suggests that a proximal tibial cut with a greater posterior tibial slope may reduce the chance of tibial loosening and increase postoperative knee range of motion, especially when using posterior cruciate ligament-retaining designs

A Composite Seyfert 2 X-ray Spectrum: Implications for the Origin of the Cosmic X-ray Background

We present a composite 1-10 keV Seyfert 2 X-ray spectrum, derived from ASCA observations of a distance-limited sample of nearby galaxies. All 29 observed objects were detected. Above ~3 keV, the composite spectrum is inverted, confirming that Seyfert 2 galaxies as a class have the spectral properties necessary to explain the flat shape of the cosmic X-ray background spectrum. Integrating the composite spectrum over redshift, we find that the total emission from Seyfert 2 galaxies, combined with the expected contribution from unabsorbed type 1 objects, provides an excellent match to the spectrum and intensity of the hard X-ray background. The principal uncertainty in this procedure is the cosmic evolution of the Seyfert 2 X-ray luminosity function. Separate composite spectra for objects in our sample with and without polarized broad optical emission lines are also presented.Comment: 11 pages (AASTeX), including 3 figures. Accepted for publication in ApJ Letter

A comparison of registration errors with imageless computer navigation during MIS total knee arthroplasty versus standard incision total knee arthroplasty: A cadaveric study

© 2015 The Authors. Optimal component alignment in total knee arthroplasty has been associated with better functional outcome as well as improved implant longevity. The ability to align components optimally during minimally invasive (MIS) total knee replacement (TKR) has been a cause of concern. Computer navigation is a useful aid in achieving the desired alignment although it is limited by the error during the manual registration of landmarks. Our study aims to compare the registration process error between a standard and a MIS surgical approach. We hypothesized that performing the registration error via an MIS approach would increase the registration process error. Five fresh frozen lower limbs were routinely prepared and draped. The registration process was performed through an MIS approach. This was then extended to the standard approach and the registration was performed again. Two surgeons performed the registration process five times with each approach. Performing the registration process through the MIS approach was not associated with higher error compared to the standard approach in the alignment parameters of interest. This rejects our hypothesis. Image-free navigated MIS TKR does not appear to carry higher risk of component malalignment due to the registration process error. Navigation can be used during MIS TKR to improve alignment without reduced accuracy due to the approac

A biomechanical study of the Birmingham mid head resection arthroplasty:Effect of stem size on femoral neck fracture

The Birmingham mid head resection (BMHR) arthroplasty can be used as an alternative to conventional stemmed total hip arthroplasty in young patients unsuitable for hip resurfacing. This study investigated the effect of stem size on femoral neck fracture in the BMHR. Sawbones composite femurs were randomly allocated to one of the following groups: (1) unprepared femur with no prosthesis, (2) femur prepared with a Birmingham hip resurfacing (BHR) prosthesis, (3) femur prepared with a BMHR stem size 1 (BMHR-1) and (4) femur prepared with a BMHR stem size 3 (BMHR-3). Each femur was subjected to a compressive force using a materials testing machine until fracture of the femoral neck occurred. The highest force at fracture was in the unprepared femurs with a mean (±standard deviation) force at failure of 5.9 ± 0.2 kN. The mean force at failure for the femurs fitted with a prosthesis was 2.6 ± 0.4, 3.0 ± 0.4 and 3.5 ± 0.5 kN for the BHR, BMHR-1 and BMHR-3, respectively. Statistical analysis showed that the failure force for the unprepared femur was significantly ( p&lt;0.05) greater than that of the BHR, BMHR-1 and BMHR-3. There was a significant difference ( p&lt;0.05) between the force at failure for the BMHR-1 and BMHR-3, indicating that these two stem sizes have an effect on fracture force. </jats:p

Assistive devices, hip precautions, environmental modifications and training to prevent dislocation and improve function after hip arthroplasty (Review)

Background: Total hip arthroplasty (THA) is one of the most common orthopaedic operations performed worldwide. Painful osteoarthritis of the hip is the primary indication for THA. Following THA, people have conventionally been provided with equipment, such as raised toilet seats and chairs, and educated to avoid activities that could cause the hip joint to be in a position of flexion over 90 degrees, or adduction or rotation past the midline. These aspects of occupational therapy have been advocated to reduce the risks of prosthesis dislocation. However, the appropriateness of these recommendations has been questioned. Objectives: To assess the effects of provision of assistive devices, education on hip precautions, environmental modifications and training in activities of daily living (ADL) and extended ADL (EADL) for people undergoing THA. Search methods: We searched MEDLINE (1946 to April 2016), EMBASE (1947 to April 2016), the Cochrane Library including CENTRAL (Issue 4 of 12, 2016), Database of Reviews of Effects (DARE), Health Technology Assessment (HTA), Economic Evaluations Database (EED), CINAHL, PEDro and CIRRIE from inception to April 2016. In addition we checked Controlled Clinical Trials, Clinicaltrials.gov, the National Institutes of Health Trial Registry, theWorld Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and the OpenGrey database from inception to April 2016. Selection criteria: We included randomised controlled trials (RCTs), quasi-RCTs and cluster-RCTs that evaluated the effectiveness of the provision of assistive devices, education on hip precautions, environmental modifications, or training in ADL and EADL for people undergoing THA. The main outcomes of interest were pain, function, health-related quality of life (HRQOL), global assessment of treatment success, reoperation rate, hip dislocation and adverse events. Data collection and analysis: We used standard methodological procedures recognised by Cochrane. We conducted a systematic literature search using several databases and contacted corresponding authors, appraised the evidence using the Cochrane risk of bias tool, analysed the data using a narrative analysis approach (as it was not possible to conduct a meta-analysis due to heterogeneity in interventions), and interpreted all outcomes using the GRADE approach. Main results: We included three trials with a total of 492 participants who had received 530 THA. The evidence presented with a high risk of performance, detection and reporting bias. One study (81 participants) compared outcomes for participants randomised to the provision of hip precautions, equipment and functional restrictions versus no provision of hip precautions, equipment or functional restrictions. Due to the quality of evidence being very low, we are uncertain if the provision of hip precautions, equipment and functional restrictions improved function measured using the Harris Hip Score at 12 month follow-up, or health-related quality of life (HRQOL) measured by the Short Form-12 at four week follow-up, compared to not providing this. There were no incidences of hip dislocation or adverse events in either group during the initial 12 postoperative months. The study did not measure pain score, global assessment of treatment success or total adverse events. One study (265 participants; 303THAs) evaluated the provision of hip precautions with versus without the prescription of postoperative equipment and restrictions to functional activities. Due to the quality of evidence being very low, we are uncertain if perceived satisfaction in the rate of recovery differed in people who were not prescribed postoperative equipment and restrictions (135/151 satisfied) compared to those prescribed equipment and restrictions (113/152) (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.75 to 0.93; 265 participants, one trial; number needed to treat for an additional beneficial outcome (NNTB) = 7). Due to the low quality evidence, we are uncertain if the incidence of hip dislocation differed between participants provided with hip precautions with (1/152) compared to without providing equipment or restrictions post-THA (0/151) (RR 2.98, 95% CI 0.12 to 72.59). The study did not measure pain, function, HRQOL, re-operation rates or total adverse events. One study (146 participants) investigated the provision of an enhanced postoperative education and rehabilitation service on hospital discharge to promote functional ADL versus a conventional rehabilitation intervention in the community. This study was of very low quality evidence. We were uncertain if the provision of enhanced postoperative education and rehabilitation improved function at six months follow-up, when assessed using the Objective and Subjective Functional Capability Index (146 participants, one trial; P > 0.05; no numerical results provided) compared to conventional rehabilitation. The study did not measure pain score, HRQOL, global assessment of treatment success, hip dislocation, re-operation rate or total adverse events. Authors’ conclusions: Very low quality evidence is available from single trials, thus we are uncertain if hip precautions with or without the addition of equipment and functional restrictions are effective in preventing dislocation and improving outcomes after THA. There is also insufficient evidence to support or refute the adoption of a postoperative community rehabilitation programme consisting of functional reintegration and education compared to conventional rehabilitation strategies based on functional outcomes. Further high-quality trials are warranted to assess the outcomes of different occupational therapy interventions both in the short and longer-term for those who undergo THA. An assessment of the impact of such interventions on pain and restriction on personal ADL, EADL and instrumental ADL is needed, and also of functional integration-type interventions rather than just hip precautions,equipment and restrictions

Femtolensing and Picolensing by Axion Miniclusters

Non-linear effects in the evolution of the axion field in the early Universe may lead to the formation of gravitationally bound clumps of axions, known as ``miniclusters.'' Minicluster masses and radii should be in the range $M_{\rm mc}\sim10^{-12} M_\odot$ and $R_{\rm mc} \sim 10^{10}$cm, and in plausible early-Universe scenarios a significant fraction of the mass density of the Universe may be in the form of axion miniclusters. If such axion miniclusters exist, they would have the physical properties required to be detected by ``femtolensing.''Comment: 7 pages plus 2 figures (Fig.1 avalible upon request), LaTe