Some Exact Solutions for Maximally Symmetric Topological Defects in Anti de Sitter Space

We obtain exact analytical solutions for a class of SO($l$) Higgs field theories in a non-dynamic background $n$-dimensional anti de Sitter space. These finite transverse energy solutions are maximally symmetric $p$-dimensional topological defects where $n=(p+1)+l$. The radius of curvature of anti de Sitter space provides an extra length scale that allows us to study the equations of motion in a limit where the masses of the Higgs field and the massive vector bosons are both vanishing. We call this the double BPS limit. In anti de Sitter space, the equations of motion depend on both $p$ and $l$. The exact analytical solutions are expressed in terms of standard special functions. The known exact analytical solutions are for kink-like defects ($p=0,1,2,\dotsc;\, l=1$), vortex-like defects ($p=1,2,3;\, l=2$), and the 'tHooft-Polyakov monopole ($p=0;\, l=3$). A bonus is that the double BPS limit automatically gives a maximally symmetric classical glueball type solution. In certain cases where we did not find an analytic solution, we present numerical solutions to the equations of motion. The asymptotically exponentially increasing volume with distance of anti de Sitter space imposes different constraints than those found in the study of defects in Minkowski space.Comment: 45 pages, 19 figures. In version 2: added two paragraphs about how our double BPS limit automatically gives a solution to the Yang-Mills equation, and related it to Yang-Mills solutions in AdS_4 that appeared on the same day in eprint 1708.0636

Perturbations to Generalized Kink-like Topological Defects in AdSAdS

We explore perturbations to a kink-like (codimension 1) topological defect whose world brane is $AdS_{q}$ embedded into $AdS_{q+1}$. Previously, we found solutions in the limit the mass of the scalar field vanishes. In this article we extend a calculation previously done in $AdS_{2}$ to higher-dimensional embedding spaces and find that all perturbations to the mass of the field are stable to first order as expected in a theory with topological defects. We find that the equation of motion to the correction strongly resembles a problem well-known in quantum mechanics.Comment: 23 pages, 6 figure

Alignment in total knee arthroplasty : what’s in a name?

Dissatisfaction following total knee arthroplasty is a well-documented phenomenon. Although many factors have been implicated, including modifiable and nonmodifiable patient factors, emphasis over the past decade has been on implant alignment and stability as both a cause of, and a solution to, this problem. Several alignment targets have evolved with a proliferation of techniques following the introduction of computer and robotic-assisted surgery. Mechanical alignment targets may achieve mechanically-sound alignment while ignoring the soft tissue envelope; kinematic alignment respects the soft tissue envelope while ignoring the mechanical environment. Functional alignment is proposed as a hybrid technique to allow mechanically-sound, soft tissue-friendly alignment targets to be identified and achieved

The Federal Reserve and market confidence

We discover a novel monetary policy shock that has a widespread impact on aggregate financial conditions. Our shock can be summarized by the response of long-horizon yields to Federal Open Market Committee (FOMC) announcements; not only is it orthogonal to changes in the near-term path of policy rates, but it also explains more than half of the abnormal variation in the yield curve on announcement days. We find that our long-rate shock is positively related to changes in real interest rates and market volatility, and negatively related to market returns and mortgage demand, consistent with policy announcements affecting market confidence. Our results demonstrate that Federal Reserve pronouncements influence markets independent of changes in the stance of conventional monetary policy

Effect of water, sanitation, and hygiene on the prevention of trachoma: a systematic review and meta-analysis.

BACKGROUND: Trachoma is the world's leading cause of infectious blindness. The World Health Organization (WHO) has endorsed the SAFE strategy in order to eliminate blindness due to trachoma by 2020 through "surgery," "antibiotics," "facial cleanliness," and "environmental improvement." While the S and A components have been widely implemented, evidence and specific targets are lacking for the F and E components, of which water, sanitation, and hygiene (WASH) are critical elements. Data on the impact of WASH on trachoma are needed to support policy and program recommendations. Our objective was to systematically review the literature and conduct meta-analyses where possible to report the effects of WASH conditions on trachoma and identify research gaps. METHODS AND FINDINGS: We systematically searched PubMed, Embase, ISI Web of Knowledge, MedCarib, Lilacs, REPIDISCA, DESASTRES, and African Index Medicus databases through October 27, 2013 with no restrictions on language or year of publication. Studies were eligible for inclusion if they reported a measure of the effect of WASH on trachoma, either active disease indicated by observed signs of trachomatous inflammation or Chlamydia trachomatis infection diagnosed using PCR. We identified 86 studies that reported a measure of the effect of WASH on trachoma. To evaluate study quality, we developed a set of criteria derived from the GRADE methodology. Publication bias was assessed using funnel plots. If three or more studies reported measures of effect for a comparable WASH exposure and trachoma outcome, we conducted a random-effects meta-analysis. We conducted 15 meta-analyses for specific exposure-outcome pairs. Access to sanitation was associated with lower trachoma as measured by the presence of trachomatous inflammation-follicular or trachomatous inflammation-intense (TF/TI) (odds ratio [OR] 0.85, 95% CI 0.75-0.95) and C. trachomatis infection (OR 0.67, 95% CI 0.55-0.78). Having a clean face was significantly associated with reduced odds of TF/TI (OR 0.42, 95% CI 0.32-0.52), as were facial cleanliness indicators lack of ocular discharge (OR 0.42, 95% CI 0.23-0.61) and lack of nasal discharge (OR 0.62, 95% CI 0.52-0.72). Facial cleanliness indicators were also associated with reduced odds of C. trachomatis infection: lack of ocular discharge (OR 0.40, 95% CI 0.31-0.49) and lack of nasal discharge (OR 0.56, 95% CI 0.37-0.76). Other hygiene factors found to be significantly associated with reduced TF/TI included face washing at least once daily (OR 0.76, 95% CI 0.57-0.96), face washing at least twice daily (OR 0.85, 95% CI 0.80-0.90), soap use (OR 0.76, 95% CI 0.59-0.93), towel use (OR 0.65, 95% CI 0.53-0.78), and daily bathing practices (OR 0.76, 95% CI 0.53-0.99). Living within 1 km of a water source was not found to be significantly associated with TF/TI or C. trachomatis infection, and the use of sanitation facilities was not found to be significantly associated with TF/TI. CONCLUSIONS: We found strong evidence to support F and E components of the SAFE strategy. Though limitations included moderate to high heterogenity, low study quality, and the lack of standard definitions, these findings support the importance of WASH in trachoma elimination strategies and the need for the development of standardized approaches to measuring WASH in trachoma control programs

IO vs OI in Higher-Order Recursion Schemes

We propose a study of the modes of derivation of higher-order recursion schemes, proving that value trees obtained from schemes using innermost-outermost derivations (IO) are the same as those obtained using unrestricted derivations. Given that higher-order recursion schemes can be used as a model of functional programs, innermost-outermost derivations policy represents a theoretical view point of call by value evaluation strategy.Comment: In Proceedings FICS 2012, arXiv:1202.317

Delta Opioid activation of the Mitogen-activated protein kinase cascade does not require transphosphorylation of Receptor Tyrosine Kinases

BACKGROUND: In this study, we investigated the mechanism(s) by which delta opioids induce their potent activation of extracellular signal-regulated protein kinases (ERKs) in different cell lines expressing the cloned δ-opioid receptor (δ-OR). While it has been known for some time that OR stimulation leads to the phosphorylation of both ERK isoforms, the exact progression of events has remained elusive. RESULTS: Our results indicate that the transphosphorylation of an endogenous epidermal growth factor receptor (EGFR) in the human embryonic kidney (HEK-293) cell line does not occur when co-expressed δ-ORs are stimulated by the δ-opioid agonist, D-Ser-Leu-enkephalin-Thr (DSLET). Moreover, neither pre-incubation of cultures with the selective EGFR antagonist, AG1478, nor down-regulation of the EGFR to a point where EGF could no longer activate ERKs had an inhibitory effect on ERK activation by DSLET. These results appear to rule out any structural or catalytic role for the EGFR in the δ-opioid-mediated MAPK cascade. To confirm these results, we used C6 glioma cells, a cell line devoid of the EGFR. In δ-OR-expressing C6 glioma cells, opioids produce a robust phosphorylation of ERK 1 and 2, whereas EGF has no stimulatory effect. Furthermore, antagonists to the RTKs that are endogenously expressed in C6 glioma cells (insulin receptor (IR) and platelet-derived growth factor receptor (PDGFR)) were unable to reduce opioid-mediated ERK activation. CONCLUSION: Taken together, these data suggest that the transactivation of resident RTKs does not appear to be required for OR-mediated ERK phosphorylation and that the tyrosine-phosphorylated δ-OR, itself, is likely to act as its own signalling scaffold

The impact of surgeon volume and training status on implant alignment in total knee arthroplasty

BACKGROUND: Implant malalignment may predispose patients to prosthetic failure following total knee arthroplasty (TKA). A more thorough understanding of the surgeon-specific factors that contribute to implant malalignment following TKA may uncover actionable strategies for improving implant survival. The purpose of this study was to determine the impact of surgeon volume and training status on malalignment. METHODS: In this retrospective multicenter study, we performed a radiographic analysis of 1,570 primary TKAs performed at 4 private academic and state-funded centers in the U.S. and U.K. Surgeons were categorized as high-volume (≥50 TKAs/year) or low-volume (\u3c50 TKAs/year), and as a trainee (fellow/resident under the supervision of an attending surgeon) or a non-trainee (attending surgeon). On the basis of these designations, 3 groups were defined: high-volume non-trainee, low-volume non-trainee, and trainee. The postoperative medial distal femoral angle (DFA), medial proximal tibial angle (PTA), and posterior tibial slope angle (PSA) were radiographically measured. Outlier measurements were defined as follows: DFA, outside of 5° ± 3° of valgus; PTA, \u3e±3° deviation from the neutral axis; and PSA, \u3c0° or \u3e7° of flexion for cruciate-retaining or \u3c0° or \u3e5° of flexion for posterior-stabilized TKAs. Far outliers were defined as measurements falling \u3e± 2° outside of these ranges. The proportions of outliers were compared between the groups using univariate and multivariate analyses. RESULTS: When comparing the high and low-volume non-trainee groups using univariate analysis, the proportions of knees with outlier measurements for the PTA (5.3% versus 17.4%) and PSA (17.4% versus 28.3%) and the proportion of total outliers (11.8% versus 20.7%) were significantly lower in the high-volume group (all p \u3c 0.001). The proportions of DFA (1.9% versus 6.5%), PTA (1.8% versus 5.7%), PSA (5.5% versus 12.6%), and total far outliers (3.1% versus 8.3%) were also significantly lower in the high-volume non-trainee group (all p \u3c 0.001). Compared with the trainee group, the high-volume non-trainee group had significantly lower proportions of DFA (12.6% versus 21.6%), PTA (5.3% versus 12.0%), PSA (17.4% versus 33.3%), and total outliers (11.8% versus 22.3%) (all p \u3c 0.001) as well as DFA (1.9% versus 3.9%; p = 0.027), PSA (5.5% versus 12.6%; p \u3c 0.001), and total far outliers (3.1% versus 6.4%; p = 0.004). No significant differences were identified when comparing the low-volume non-trainee group and the trainee group, with the exception of PTA outliers (17.4% versus 12.0%; p = 0.041) and PTA far outliers (5.7% versus 2.6%; p = 0.033). Findings from multivariate analysis accounting for the effects of patient age, body mass index, and individual surgeon demonstrated similar results. CONCLUSIONS: Low surgical volume and trainee status were risk factors for outlier and far-outlier malalignment in primary TKA, even when accounting for differences in individual surgeon and patient characteristics. Trainee surgeons performed similarly, and certainly not inferiorly, to low-volume non-trainee surgeons. Even among high-volume non-trainees, the best-performing cohort in our study, the proportion of TKA alignment outliers was still high. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence

Respiratory gas kinetics in patients with congestive heart failure during recovery from peak exercise

Background: Cardiopulmonary Exercise Testing (CPX) is essential for the assessment of exercise capacity for patients with Chronic Heart Failure (CHF). Respiratory gas and hemodynamic parameters such as Ventilatory Efficiency (VE/VCO2 slope), peak oxygen uptake (peak VO2), and heart rate recovery are established diagnostic and prognostic markers for clinical populations. Previous studies have suggested the clinical value of metrics related to respiratory gas collected during recovery from peak exercise, particularly recovery time to 50% (T1/2) of peak VO2. The current study explores these metrics in detail during recovery from peak exercise in CHF. Methods: Patients with CHF who were referred for CPX and healthy individuals without formal diagnoses were assessed for inclusion. All subjects performed CPX on cycle ergometers to volitional exhaustion and were monitored for at least five minutes of recovery. CPX data were analyzed for overshoot of respiratory exchange ratio (RER=VCO2/VO2), ventilatory equivalent for oxygen (VE/VO2), end-tidal partial pressure of oxygen (PETO2), and T1/2 of peak VO2 and VCO2. Results: Thirty-two patients with CHF and 30 controls were included. Peak VO2 differed significantly between patients and controls (13.5 ± 3.8 vs. 32.5 ± 9.8 mL/Kg*min−1, p < 0.001). Mean Left Ventricular Ejection Fraction (LVEF) was 35.9 ± 9.8% for patients with CHF compared to 61.1 ± 8.2% in the control group. The T1/2 of VO2, VCO2 and VE was significantly higher in patients (111.3 ± 51.0, 132.0 ± 38.8 and 155.6 ± 45.5s) than in controls (58.08 ± 13.2, 74.3 ± 21.1, 96.7 ± 36.8s; p < 0.001) while the overshoot of PETO2, VE/VO2 and RER was significantly lower in patients (7.2 ± 3.3, 41.9 ± 29.1 and 25.0 ± 13.6%) than in controls (10.1 ± 4.6, 62.1 ± 17.7 and 38.7 ± 15.1%; all p < 0.01). Most of the recovery metrics were significantly correlated with peak VO2 in CHF patients, but not with LVEF. Conclusions: Patients with CHF have a significantly blunted recovery from peak exercise. This is reflected in delays of VO2, VCO2, VE, PETO2, RER and VE/VO2, reflecting a greater energy required to return to baseline. Abnormal respiratory gas kinetics in CHF was negatively correlated with peak VO2 but not baseline LVEF