Dynamics of Black Hole Pairs I: Periodic Tables

Although the orbits of comparable mass, spinning black holes seem to defy simple decoding, we find a means to decipher all such orbits. The dynamics is complicated by extreme perihelion precession compounded by spin-induced precession. We are able to quantitatively define and describe the fully three dimensional motion of comparable mass binaries with one black hole spinning and expose an underlying simplicity. To do so, we untangle the dynamics by capturing the motion in the orbital plane. Our results are twofold: (1) We derive highly simplified equations of motion in a non-orthogonal orbital basis, and (2) we define a complete taxonomy for fully three-dimensional orbits. More than just a naming system, the taxonomy provides unambiguous and quantitative descriptions of the orbits, including a determination of the zoom-whirliness of any given orbit. Through a correspondence with the rationals, we are able to show that zoom-whirl behavior is prevalent in comparable mass binaries in the strong-field regime. A first significant conclusion that can be drawn from this analysis is that all generic orbits in the final stages of inspiral under gravitational radiation losses are characterized by precessing clovers with few leaves and that no orbit will behave like the tightly precessing ellipse of Mercury. The gravitational waveform produced by these low-leaf clovers will reflect the natural harmonics of the orbital basis -- harmonics that, importantly, depend only on radius. The significance for gravitational wave astronomy will depend on the number of windings the pair executes in the strong-field regime and could be more conspicuous for intermediate mass pairs than for stellar mass pairs.Comment: 19 pages, lots of figure

The Unexpected Pitter Patter: New-Onset Atrial Fibrillation in Pregnancy

Background. Atrial fibrillation is a relatively uncommon but dangerous complication of pregnancy. Emergency physicians must know how to treat both stable and unstable tachycardias in late pregnancy. In this case, a 40-year-old female with a cerclage due to incompetent cervix and previous preterm deliveries presents in new-onset atrial fibrillation. Case Report. A previously healthy 40-year-old African American G2 P1 female with a 23-week twin gestation complicated by an incompetent cervix requiring a cervical cerclage presented to the emergency department with intermittent palpitations and shortness of breath for the past two months. EMS noted the patient to have a tachydysrhythmia, atrial fibrillation with rapid ventricular response. She was placed on a diltiazem drip, which was titrated to 15 mg/hr without successful rate control. Her heart rate remained in the 130s and the rhythm continued to be atrial fibrillation with RVR. Digoxin was then added as a second agent, and discussions about the potential risks of cardioversion in pregnancy ensued. Fortunately, the patient converted to sinus rhythm before cardioversion became necessary. The digoxin was discontinued; the diltiazem was also discontinued after the patient subsequently developed hypotension. “Why Should Emergency Physicians Be Aware of This?” New-onset atrial fibrillation is rare in pregnancy but can increase the mortality and morbidity of the mother and fetus if not treated promptly

Homoclinic Orbits around Spinning Black Holes I: Exact Solution for the Kerr Separatrix

Under the dissipative effects of gravitational radiation, black hole binaries will transition from an inspiral to a plunge. The separatrix between bound and plunging orbits features prominently in the transition. For equatorial Kerr orbits, we show that the separatrix is a homoclinic orbit in one-to-one correspondence with an energetically-bound, unstable circular orbit. After providing a definition of homoclinic orbits, we exploit their correspondence with circular orbits and derive exact solutions for them. This paper focuses on homoclinic behavior in physical space, while in a companion paper we paint the complementary phase space portrait. The exact results for the Kerr separatrix could be useful for analytic or numerical studies of the transition from inspiral to plunge.Comment: 21 pages, some figure

Quantitative Neuropathological Assessment to Investigate Cerebral Multi-Morbidity

The aging brain is characterized by the simultaneous presence of multiple pathologies, and the prevalence of cerebral multi-morbidity increases with age. To understand the impact of each subtype of pathology and the combined effects of cerebral multi-morbidity on clinical signs and symptoms, large clinico-pathological correlative studies have been performed. However, such studies are often based on semi-quantitative assessment of neuropathological hallmark lesions. Here, we discuss some of the new methods for high-throughput quantitative neuropathological assessment. These methods combine increased quantitative rigor with the added technical capacity of computers and networked analyses. There are abundant new opportunities - with specific techniques that include slide scanners, automated microscopes, and tissue microarrays - and also potential pitfalls. We conclude that quantitative and digital neuropathologic approaches will be key resources to further elucidate cerebral multi-morbidity in the aged brain and also hold the potential for changing routine neuropathologic diagnoses

Examining associations between brain morphology in late childhood and early alcohol or tobacco use initiation in adolescence:findings from a large prospective cohort

A prominent challenge in understanding neural consequences of substance use involves disentangling predispositional risk factors from resulting consequences of substance use. Existing literature has identified pre-existing brain variations as vulnerability markers for substance use throughout adolescence. As early initiation of use is an important predictor for later substance use problems, we examined whether pre-existing brain variations are associated with early initiation of use. In the Generation R Study, a prospective population-based cohort, brain morphology (gray matter volume, cortical thickness and surface area) was assessed at ages 10 and 14 using neuroimaging. In the second wave, participants reported on alcohol and tobacco use initiation. From a base study population (N = 3019), we examined the longitudinal (N = 2218) and cross-sectional (N = 1817) association between brain morphology of frontolimbic regions of interest known to be associated with substance use risk, and very early (age &lt; 13) alcohol/tobacco use initiation. Additionally, longitudinal and cross-sectional associations were examined with a brain surface-based approach. Models were adjusted for age at neuroimaging, sex and relevant sociodemographic factors. No associations were found between brain morphology (ages 10 and 14) and early alcohol/tobacco use initiation (&lt;13 years). Sex-specific analyses suggested a cross-sectional association between smaller brain volume and early initiated tobacco use in girls. Our findings are important for interpreting studies examining neural consequences of substance use in the general population. Future longitudinal studies are needed to specify whether these findings can be extended to initiation and continuation of alcohol/tobacco use in later stages of adolescence.</p

Environmental control on the occurrence of high-coercivity magnetic minerals and formation of iron sulfides in a 640 ka sediment sequence from Lake Ohrid (Balkans)

The bulk magnetic mineral record from Lake Ohrid, spanning the past 637 kyr, reflects large-scale shifts in hydrological conditions, and, superimposed, a strong signal of environmental conditions on glacial–interglacial and millennial timescales. A shift in the formation of early diagenetic ferrimagnetic iron sulfides to siderites is observed around 320 ka. This change is probably associated with variable availability of sulfide in the pore water. We propose that sulfate concentrations were significantly higher before  ∼  320 ka, due to either a higher sulfate flux or lower dilution of lake sulfate due to a smaller water volume. Diagenetic iron minerals appear more abundant during glacials, which are generally characterized by higher Fe / Ca ratios in the sediments. While in the lower part of the core the ferrimagnetic sulfide signal overprints the primary detrital magnetic signal, the upper part of the core is dominated by variable proportions of high- to low-coercivity iron oxides. Glacial sediments are characterized by high concentration of high-coercivity magnetic minerals (hematite, goethite), which relate to enhanced erosion of soils that had formed during preceding interglacials. Superimposed on the glacial–interglacial behavior are millennial-scale oscillations in the magnetic mineral composition that parallel variations in summer insolation. Like the processes on glacial–interglacial timescales, low summer insolation and a retreat in vegetation resulted in enhanced erosion of soil material. Our study highlights that rock-magnetic studies, in concert with geochemical and sedimentological investigations, provide a multi-level contribution to environmental reconstructions, since the magnetic properties can mirror both environmental conditions on land and intra-lake processes

The Accessibility of Birth Control Methods: Assessing the Household Demographics & Socioeconomic Factors on the Demand for Contraceptives in the Philippines

The Reproductive Health Bill No. 5043 (RH Bill) is a controversial issue in the Philippines. It has been a topic of debates by public and private groups. The RH Bill will allow citizens universal access to medically safe, affordable, and effective reproductive health care services and information. It encourages the use of contraceptives, like condoms, birth-control pills. It aims to reduce the rapid increase in the Philippine population. Hence, preventing it from reaching a hundred million in five years as estimated by the Department of Health. This study highlights the most controversial issue of the bill: Making contraceptives readily available to everyone. Prime focus is given to accessibility of contraceptives and its relationship to the behavior of Filipinos with respect to changes in household characteristics, religion, economic status, and other related variables

High-resolution three-dimensional extracellular recording of neuronal activity with microfabricated electrode arrays

Microelectrode array recordings of neuronal activity present significant opportunities for studying the brain with single-cell and spike-time precision. However, challenges in device manufacturing constrain dense multisite recordings to two spatial dimensions, whereas access to the three-dimensional (3D) structure of many brain regions appears to remain a challenge. To overcome this limitation, we present two novel recording modalities of silicon-based devices aimed at establishing 3D functionality. First, we fabricated a dual-side electrode array by patterning recording sites on both the front and back of an implantable microstructure. We found that the majority of single-unit spikes could not be simultaneously detected from both sides, suggesting that in addition to providing higher spatial resolution measurements than that of single-side devices, dual-side arrays also lead to increased recording yield. Second, we obtained recordings along three principal directions with a multilayer array and demonstrated 3D spike source localization within the enclosed measurement space. The large-scale integration of such dual-side and multilayer arrays is expected to provide massively parallel recording capabilities in the brain

Initial Management of Meningiomas: Analysis of the National Cancer Database

BACKGROUND: Meningiomas are the most common central nervous system tumor. We describe current trends in treatment and survival using the largest cancer dataset in the United States. METHODS: We analyzed the National Cancer Database from 2004 to 2014, for all patients with diagnosis of meningioma. RESULTS: 201,765 cases were analyzed. Patients were most commonly White (81.9%) females (73.2%) with a median age of 64 years. Fifty percent of patients were diagnosed by imaging. Patients were reported as grade I (24.9%), grade II (5.0%), grade III (0.7%), or unknown WHO grade (69.4%). Patients diagnosed by imaging were older, received treatment in community facilities, had higher Charlson-Deyo score, and a lower rate of private insurance. Watchful waiting was the most common treatment modality (46.7%), followed by surgery only (40%). Grade II and III patients were more likely to receive therapy. Watchful waiting increased from 35.2% in 2004 to 51.4% in 2014. Younger age, male gender, private insurance, and treatment in academic facilities were determinants for receipt of surgery and/or radiation. Median survival was 12.6 years, higher in histologically confirmed cases (13.1 years). Older patients, Blacks, males, those that received radiation plus surgery, and were treated in community facilities had an increased risk of mortality. CONCLUSIONS: Over half of patients were diagnosed by imaging, suggesting a higher role of clinical determinants over histological confirmation in treatment decisions. Watchful waiting as initial management is increasing. Our survival analysis favored histological confirmation. Patients receiving radiation and surgery had an increased risk of mortality

Disease-Specific Electrocardiographic Lead Positioning for Early Detection of Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by replacement of cardiomyocytes by fibrofatty tissue which can lead to ventricular arrhythmias, heart failure or sudden cardiac death. Genetic defects in desmosomal proteins, as plakophilin-2 (PKP2), are known to contribute to disease development. Current electrocardiographic (ECG) criteria for ARVC diagnosis only focus on right precordial leads, but sensitivity of current depolarization criteria is limited. This study aimed to identify additional depolarization criteria with most optimal lead configurations for early detection of ARVC in PKP2 pathogenic mutation carriers. In PKP2-positive ARVC patients (n=7), PKP2 pathogenic variant carriers (n=16) and control subjects without structural heart disease (n=9), 67-lead body surface potential maps (BSPM) were obtained. Terminal QRS-integrals were determined and quantitatively compared to controls using departure mapping. Significantly different terminal QRS-integrals were identified in lead 34 (conventional V3), 40 and 41 (conventional V4). To conclude, a clear distinction between ARVC patients, asymptomatic mutation carriers and healthy controls was observed