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Transmastoid occlusion of the posterior or superior semicircular canal is an effective and safe management option in patients with refractory benign paroxysmal positional vertigo or symptomatic superior semicircular canal dehiscence. A method of quantifying successful canal occlusion surgery is described.
This paper presents representative patients with intractable benign paroxysmal positional vertigo or symptomatic superior semicircular canal dehiscence, who underwent transmastoid occlusion of the posterior or superior semicircular canal respectively. Vestibular function was assessed pre- and post-operatively. The video head impulse test was included as a measure of semicircular canal and vestibulo-ocular reflex functions.
Post-operative video head impulse testing showed reduced vestibulo-ocular reflex gain in occluded canals. Gain remained normal in the non-operated canals. Post-operative audiometry demonstrated no change in hearing in the benign paroxysmal positional vertigo patient and slight hearing improvement in the superior semicircular canal dehiscence syndrome patient.
Transmastoid occlusion of the posterior or superior semicircular canal is effective and safe for treating troublesome benign paroxysmal positional vertigo or symptomatic superior semicircular canal dehiscence. Post-operative video head impulse testing demonstrating a reduction in vestibulo-ocular reflex gain can reliably confirm successful occlusion of the canal and is a useful adjunct in post-operative evaluation.
Analysis of a recent surge of Morsnevbreen, Svalbard, is used to test predictions of the enthalpy balance theory of surging. High-resolution time series of velocities, ice thickness and crevasse distribution allow key elements of the enthalpy (internal energy) budget to be quantified for different stages of the surge cycle. During quiescence (1936–1990), velocities were very low, and geothermal heat slowly built-up enthalpy at the bed. Measurable mass transfer and frictional heating began in 1990–2010, then positive frictional heating-velocity feedbacks caused gradual acceleration from 2010 to 2015. Rapid acceleration occurred in summer 2016, when extensive crevassing and positive air temperatures allowed significant surface to bed drainage. The surge front reached the terminus in October 2016, coincident with a drop in velocities. Ice plumes in the fjord are interpreted as discharge of large volumes of supercooled water from the bed. Surge termination was prolonged, however, indicating persistence of an inefficient drainage system. The observations closely match predictions of the theory, particularly build-up of enthalpy from geothermal and frictional heat, and surface meltwater, and the concomitant changes in ice-surface elevation and velocity. Additional characteristics of the surge reflect spatial processes not represented in the model, but can be explained with respect to enthalpy gradients.
Archaeological survey and excavations in the mangrove-estuary zone south of Izapa have generated an understanding of how the environment and human exploitation patterns changed during the Archaic and Formative periods. Archaic-period archaeological remains are not present, but the sedimentary record shows that Archaic people were clearing the coastal-plain forest for agricultural purposes. This activity augmented delivery of sediments to the littoral zone, which expanded the mangrove forest and created a productive environment that could be colonized by Early Formative villagers by around 1600 cal b.c. Population growth during the Early Formative created conditions that favored emergence of specialized pyro-industries, especially salt production, by around 1000 cal b.c. Production intensity increased thereafter, especially during the Late Formative period, coincident with the apogee of Izapa. Salt production became more episodic during the Terminal Formative period, when interior populations were declining to a nadir after cal a.d. 250.
The Family of Love met with considerable controversy in Elizabethan England. This article examines a series of confessions given by members and ex-members of the group before Protestant authorities. Such testimonies are less straightforward than they seem. Specifically, Familists and their opponents used confessions as an opportunity to refine their religious identities. Both sides fought to establish themselves as simple, transparent Christians even as they indulged in the twists and turns of sixteenth-century polemics. Rather than dismissing such sources as distortions, this article explores the ideological diversity that results from the attempt to derive meaning from hostile attention.
The revolutions that swept across Europe in 1848 marked a turning-point in the history of political and social thought. They raised questions of democracy, nationhood, freedom and social cohesion that have remained among the key issues of modern politics, and still help to define the major ideological currents - liberalism, socialism, republicanism, anarchism, conservatism - in which these questions continue to be debated today. This collection of essays by internationally prominent historians of political thought examines the 1848 Revolutions in a pan-European perspective, and offers research on questions of state power, nationality, religion, the economy, poverty, labour, and freedom. Even where the revolutionary movements failed to achieve their explicit objectives of transforming the state and social relations, they set the agenda for subsequent regimes, and contributed to the shaping of modern European thought and institutions.
“Where do we find ourselves?” We ask some permutation of this question in response to life events, as Ralph Waldo Emerson does to open his haunting essay on the death of his young son, the magisterial “Experience” (1844). Commemorations also compel us to make such accountings, to break from the requisite, often monotonous routines of everyday life to assess our evolutions. The sixtieth anniversary of the founding of the American Society for Theatre Research offers such an occasion, and this forum's invitation to imagine and, perhaps, sway the direction of the organization's discursive and institutional practices over the next decade or more requires, first of all, estimating where we, as scholars of theatre and performance culture, find ourselves. Although these inspections would certainly reveal actions and innovations worthy of commemoration, the more important task is to lay bare and come to grips with those assumptions, ruts, and shibboleths in our respective fields of inquiry that have become so ingrained that they have achieved a kind of sacrosanctity. We must contest and, in many cases, abandon these conceptual and analytical habits: such efforts, though to the detriment of ideology, will be to the good of the discipline and the enrichment of our individual scholarly sensibilities.
Here, we report reproducible and accurate measurement of crystallographic parameters using scanning transmission electron microscopy. This is made possible by removing drift and residual scan distortion. We demonstrate real-space lattice parameter measurements with <0.1% error for complex-layered chalcogenides Bi2Te3, Bi2Se3, and a Bi2Te2.7Se0.3 nanostructured alloy. Pairing the technique with atomic resolution spectroscopy, we connect local structure with chemistry and bonding. Combining these results with density functional theory, we show that the incorporation of Se into Bi2Te3 causes charge redistribution that anomalously increases the van der Waals gap between building blocks of the layered structure. The results show that atomic resolution imaging with electrons can accurately and robustly quantify crystallography at the nanoscale.
The proboscidean Gomphotherium is reported here from the Alajuela Formation of Panama. Gomphotherium was widespread throughout Holarctica during the Miocene, and the Panama fossil represents the extreme southernmost occurrence of this genus in the New World. Allocation of the Panama Gomphotherium to a valid species is impossible given both the fragmentary material represented and the taxonomic complexity of species assigned to this genus. In North America, Gomphotherium has a relatively long biochronological range from the middle Miocene (~15 Ma) to early Pliocene (~5 Ma). Based on morphological comparisons, the Panama Gomphotherium is either middle Miocene, thus representing the earliest-known entry of this genus into Central America, or late Miocene/early Pliocene, which challenges the currently accepted middle Miocene age of the Alajuela Formation as it has been previously reported from Panama.