Forecasting Traditional vs Blended Retirement System for Individual Service Members

Starting January 1, 2018, the Department of Defense new Blended Retirement System (BRS) will go into effect. Military members with less than twelve years of service will have the option to either remain in the current High 3 Retirement System or opt into the BRS. This decision will have a lasting impact on their lives well beyond their military careers. With this in mind, we have developed a Decision Support System that will enable service members to compare the two retirement choices in terms of annual and total lifetime expected value. There were three phases to the development of the decision support tool. First, we identified Simple Exponential Smoothing Method and Artificial Neural Networks as the most accurate forecasting techniques to predict the Thrift Savings Plan Funds’ rate of return. Next, we identified surrogate TSP portfolios based on minimizing downside risk. In the third phase, we identified risk tolerance and the continuation pay multiplier as the key drivers for differentiating between the two systems. Finally, the resulting Decision Support System leverages current time series forecasting techniques, behavioral economic theory, and Bayesian statistics to capture the complexity of this important decision while delivering relevant information to service members in a straightforward manner using an R Studio Shiny Application

Syncope or Seizure?

Syncope is a common complaint in the emergency departments, accounting for 1-2% of visits, and can approach admission rates of a staggering 85%. The causes and conditions can be numerous, ranging from benign to life threatening. A good background history can go a long way in determining the etiology of the patient’s syncope. We describe a case of an elderly male who presented with a reported chief complaint of seizures, another syncope-mimic seen in the emergency department. He had a history of CAD, HTN, AAA, and osteoarthritis but no prior history of cardiac arrhythmia, MI, or structural heart disease. The wife noticed collapse followed by seizure-like activity after opening the refrigerator. The initial EKG was non-specific. During his course in the ED there was a witnessed syncopal episode with upper extremity shaking and return to mental baseline within a minute of the event. A repeat EKG showed complete heart block. Seizures are a common presentation and chief complaint in the emergency department. It is easy to get tunnel vision in the clinical pathway and treatment plan. Other less common presentations of loss of consciousness with rhythmic shaking include convulsive syncope and should be considered. It is important to cast a wide net in the initial workup and always consider convulsive syncope, especially in an elderly patient with risk factors

Increasing Beach Recreation Benefits by Using Wetlands to Reduce Contamination

The public swimming beach at Maumee Bay State Park (MBSP) on Lake Erie is often posted for occurrences of unsafe levels of bacteria. The main source of bacteria derives from a drainage ditch that discharges near the beach. We have conducted a comprehensive study to determine the feasibility of using a constructed wetland to filter the ditch water, prior to its entry into Maumee Bay. As part of this study, we administered an on-site non-market valuation survey of beach visitors, in which observed and contingent trips to the beach were used to estimate the potential welfare benefits of the restored wetlands. The data were analyzed using three versions of the multivariate Poisson-lognormal (MPLN) model, a random effects count data model. We conclude version one, with flexible covariance structure and vehicle costs of $0.25 per mile, is the preferred version and use it to estimate an average annual willingness to pay (WTP) of$166 to construct wetlands and improve water quality. The aggregate annual benefit to an estimated 37,300 annual beach visitors is estimated as $6.19 million. The robustness of this estimate to a variety of alternative assumptions is examined.Count data model, Poisson lognormal, on-site sampling, recreation demand, wetland, simulated maximum likelihood, Community/Rural/Urban Development, Environmental Economics and Policy, Public Economics, Q51,

Atypical Presentation of Non-Aneurysmal Subarachnoid Hemorrhage

When most clinicians think of subarachnoid hemorrhages (SAH), they think of “most severe headache of my life” as the most common chief complaint. However, it is only reported in about 70% of patients with SAH. Other symptoms may include nausea and/or vomiting, stiff neck, visual disturbances, loss of consciousness, weakness, and seizures. Patient history may involve previous SAH, hypertension, oral contraceptives in women, recent trauma, family history of intracranial aneurysms, history of smoking, alcohol, and drug use. However, there are atypical causes of SAH that may be missed upon initial evaluation for patients that may not have the above mentioned symptoms or risk factors. When evaluating the patient with a neurological complaint that does not fall in the category of peripheral nervous system distribution, it is worth considering outliers that may be related to the central nervous system, such as a SAH. Working up such differentials leads to proper disposition of the patient population and decreases the possibility of long-term complications or mistreatment

Celiac Artery Aneurysm: A Rare Cause of Abdominal Pain

Celiac artery aneurysm is a very rare vascular lesion accounting for only 5.1% of all splanchnic artery aneurysms. Etiology for celiac artery aneurysm includes, but not limited to, infectious diseases, atherosclerosis, trauma, congenital conditions such as median arcuate ligament syndrome and iatrogenic causes. Etiology for abdominal pain is extensive. Patients should be evaluated for both intra-abdominal and extra-abdominal causes for pain, as presentations of a different pathophysiology vary widely. CT scan has become a mainstay part of the work for abdominal pain in the Emergency department, and often elicit pathologies that would otherwise be missed on blood work and other imaging modalities. Although rare, celiac artery aneurysm carries a high mortality rate if ruptured and therefore surgical repair is definitive care plan. Surgical repair maybe either via endovascular approach or via open surgical repair of the aneurysm preferably via prosthetic grafts

A Hidden Cause for Electrolyte Derangement in the ED: Gitelman Syndrome

Electrolyte derangements are a common finding in the emergency department, whether incidental or the cause for presenting symptoms. Gitelman syndrome (GS) can be the cause for recurrent hypokalemia and hypomagnesemia. While often diagnosed when the patient is young, a clinician should keep this on the differential when seeing repeated visits with electrolyte deficiencies and treating them. Here we discuss a case of how Gitelman syndrome has presented in the ED and what to learn from it

MUSCULAR CO-ACTIVATION IN SUBJECTS AFFECTED BY FEMOROACETABULAR IMPINGEMENT

Femoroacetabular Impingement (FAI) is a hip deformity that causes hip and groin pain. Previous research showed that FAI patients have altered hip kinetics and kinematics and pelvic kinematics. Whether or not this is due to different muscular strategies is still unclear. The purpose of this study was to investigate the muscular co-activation in FAI patients. Electromyographic signals were recorded from 16 hip muscles. The coactivation index was calculated for FAI symptomatic, asymptomatic and control groups. Even if not statistically significant, the co-activation measurements showed a trend similar to the findings for osteoarthritic (OA) patients. Additional investigations are warranted to confirm this analogy that could further relate FAI and OA development, and to confirm the hypothesis that FAI anomalies are also due to altered muscular strategies

MAXIMAL DEPTH SQUATING IN ASYMPTOMATIC UNILATERAL CAM FAI

Femoracetabular impingement (FAI) is a condition that causes hip joint pain and has been found to result in decreased range of motion. However it is not known whether biomechanical deficiencies are associated with the mechanical impingement or further underlying issues associated with pain. This study consisted of comparing the squat biomechanics of two FAI groups to a matched control group. It was found that the asymptomatic group had squat performance very similar to the control group. Both the control and asymptomatic groups were able to squat to a deeper depth, had greater pelvic range of motion and a larger maximum hip flexion angle. These findings suggest that the bone deformity might not be directly related to restricting motion for the squat, and an issue of soft tissue damage and muscle problems may be the root cause, and should be the next avenue of study

In Situ Enrichment and Epitaxial Growth of 28Si Films via Ion Beam Deposition

Isotopically enriched 28Si is an ideal material for solid state quantum computing because it interacts weakly with the spin states of embedded qubits (quantum bits) resulting in long coherence times. This is the result of eliminating the roughly 4.7 % 29Si isotopes present in natural abundance Si, which possesses nuclear spin I = 1/2 that is disruptive to qubit operation. However, high-quality 28Si is scarce and the degree to which it improves the performance of a qubit is not well understood. This leads to an important question in the Si-based quantum information field, which can be stated as "how good is good enough?" regarding the perfection of 28Si as a host medium for qubits. The focus of this thesis is to engineer a material that can address this question, specifically in terms of the enrichment. Secondary requirements for ideal 28Si films that are also pursued are crystalline perfection and high chemical purity. I report on the production and characterization of 28Si thin films that are the most highly enriched of any known 28Si material ever produced with a maximum 28Si enrichment of 99.9999819(35) % and a residual 29Si isotopic concentration of 1.27(29) x 10^-7. A hyperthermal energy ion beamline is used to produce this extreme level of enrichment starting from a natural abundance silane gas (SiH4) source. The Si is enriched in situ by mass separating the ions in a magnetic field just before deposition onto Si(100) substrates. Initial proof of principle experiments enriching 22Ne and 12C were also conducted. In the course of achieving this 28Si enrichment, I also pursue the epitaxial deposition of 28Si thin films. Characterizations of the film morphology and crystallinity are presented showing that smooth, epitaxial 28Si films are achieved using deposition temperatures between 349 C and 460 C. Crystalline defects present in these films include {111} stacking faults. When using higher deposition temperatures, I find that trace impurity compounds such as SiC cause step pinning and faceting of the growth surface leading to severely rough films. Assessments of the chemical purity of 28Si films are also presented, which show major impurities N, C, and O are present in the purest film at an atomic concentration of approximately 1 x 10^19 cm^-3, resulting in a Si purity of 99.96(2) %. Additionally, I introduce a model that describes the residual 29Si and 30Si in 28Si films, i.e. the enrichment, as the result of adsorption of diffusive natural abundance SiH4 gas from the ion source into the 28Si films during deposition. This model correlates the measured enrichments of 28Si films with the SiH4 partial pressures during deposition. An incorporation fraction for SiH4 adsorption at room temperature of s = 6:8(3) x 10^-4 is extracted. Finally, the temperature dependence of the sample enrichment is analyzed using a thermally activated incorporation model that gives an activation energy of Ec = 1.1(1) eV for the reactive sticking coefficient of SiH4