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OBJECTIVE To characterize differences in vestibular testing results among patients presenting with balance-related complaints; to stratify patterns of testing abnormalities by age. STUDY DESIGN Retrospective chart review. SETTING Academic Balance Center at a Tertiary Referral Center. PATIENT POPULATION All patients who underwent vestibular testing in a 1-year period from 2017 to 2018. MAIN OUTCOME MEASURE Balance function test results. RESULTS We reviewed 1,116 patients with age ranging from 11 to 94 years, including 521 patients ≥60 years. Most patients had at least 1 abnormal result, with only 21% of patients ≥60 years and 43% of patients

To report the audiometric and surgical outcomes of a series of patients having undergone implantation of a novel transcutaneous bone conduction implant (t-BCI).Retrospective case series.Single academic tertiary referral center.Adults (≥18 yr) implanted between December 1, 2019, and August 1, 2021, with audiometric data available before and after device implantation and a minimum of 4 weeks follow-up.Surgical t-BCI.Change in aided pure tone average (PTA) after implantation. Secondary outcomes include average operative time, and adverse events.Twenty-three patients underwent implantation of the t-BCI via either a conventional or minimally invasive surgical approach. The most common indication for implantation was unilateral conductive hearing loss with a history of chronic otitis media. The mean operative time was 59 minutes. The mean preimplantation unaided air conduction PTA was 65 dB, and mean postimplantation was 27.2 dB. The mean change in PTA was 37.8 dB, which was significant ( p0.0001). There were 30.4% of the patients that suffered from adverse events, the most common of which were pain (8.7%) and device-related complications (13%). One major adverse event occurred, involving magnet displacement that impaired device activation and required reoperation for replacement.Forming the largest series of patients implanted with this t-BCI in the published literature, our data demonstrate that implantation of the device is feasible via either a traditional or minimally invasive surgical approach, with good audiometric benefit and a favorable safety profile.

OBJECTIVE To characterize postoperative electrode functionality after adult cochlear implantation; to identify rationale and risk factors for electrode deactivation. STUDY DESIGN Retrospective Chart Review. SETTING Academic Cochlear Implant Center. SUBJECT POPULATION Five hundred nineteen cochlear implants in 433 adult patients over 5 years. INTERVENTIONS Unilateral or bilateral cochlear implantation. MAIN OUTCOME MEASURES Rate of electrode deactivation after adult cochlear implantation. RESULTS One hundred twenty (27.7%) patients experienced electrode deactivation postoperatively, involving a total of 447 electrodes. The most common reasons for deactivation were bothersome nonauditory symptoms (n = 170, 38.0%), perceived benefit by patients (n = 64, 14.3%), and bothersome auditory symptoms (n = 60, 13.4%). Four hundred nineteen (93.7%) of involved electrodes remained deactivated at most recent follow-up, whereas 28 (6.3%) were able to be reactivated. Deactivation was most likely to occur within the first 4 weeks after activation (n = 90 patients,75.0%; p

OBJECTIVE To assess the impact of reconstructive technique on the incidence of cerebrospinal fluid (CSF) leak following retrosigmoid approach to acoustic neuroma resection. STUDY DESIGN Retrospective case series. SETTING Academic medical center. PATIENTS A total of 1,200 patients with acoustic neuromas presented to our institution from 2005 to 2018. Of these, 196 patients underwent surgical resection via a retrosigmoid approach. INTERVENTION At our institution, internal auditory canal (IAC) reconstruction following a retrosigmoid approach was performed with bone wax and muscle plug or Norian hydroxyapatite bone cement from 2005 to 2013. Starting in 2014, a newer model of bone cement, Cranios hydroxyapatite, was used exclusively for reconstruction. MAIN OUTCOME MEASURES Rates of CSF leak were evaluated across different methods of IAC reconstruction and types of bone cement. Patients whose leaks were attributable to the craniectomy site were excluded from analysis. RESULTS The postoperative CSF leak rate among patients who did not receive bone cement for IAC reconstruction was 15.6% (n.5). The leak rate amongst patients who received Norian bone cement was 6.3% (n.4). After introduction of Cranios bone cement, the total leak rate decreased to 1% (n.1). Compared with all other types of closure, Cranios had a significantly reduced rate of postoperative CSF leak (p

OBJECTIVE To characterize failure rate and etiology after cochlear implantation; to identify predictors and describe outcomes after implant failure. STUDY DESIGN Retrospective chart review and systematic review of the literature using PubMed and Embase. SETTING Academic Cochlear Implant Center. SUBJECT POPULATION Four hundred ninety-eight devices in 439 distinct adult patients. INTERVENTIONS Unilateral or bilateral cochlear implantation. MAIN OUTCOME MEASURES Implant failure rate and etiology. RESULTS A total of 32 devices (5.9%) failed in 31 patients encompassing the following failure types in accordance with the European Consensus Statement of Cochlear Implants: 17 device failures (53.1%), 11 failures due to performance decrement/adverse reactions (34.4%), and 4 medical reasons (12.9%). There was no significant difference in age, sex, or manufacturer between patients with and without failures. Twenty-five percent of patients with failure leading to explantation had childhood onset of deafness compared to 12.1% of patients with adult-onset hearing loss (OR = 2.42; p = 0.04). Performance decrement/adverse reaction patients had an older average age at implantation compared to device failure patients (mean 68.5 yr 95% CI: 59.9-77.1 vs mean 47.6 yr, CI: 39.9-55.3, p

Comparison of audiometric measurements of commercially available smartphone audiogram application thresholds as compared to gold standard audiometric evaluation.A single-institution, original contribution. Ninety consecutive adult patients presenting to a tertiary care auditory clinic with auditory complaints were evaluated using standard audiometric testing and an application-based hearing test. Correlation between app results and standard audiogram for air conduction pure tone thresholds was evaluated.Mimi™ (Berlin, Germany) results for audiometric thresholds were moderately correlated with standard audiogram (r = 0.51-0.68) depending on severity. The percentage of patients whose hearing loss severity on formal audiometry results were accurately reflected in the Mimi™ (app-based hearing test: ABHT)Results from an audiometric smart phone application showed accurate categorization of hearing loss at the high and extremes as compared to standard audiometry. However, correlation of pure tone values was more variable and dependent on hearing level.

To compare outcomes transmastoid repair of spontaneous middle fossa cerebrospinal fluid (CSF) leak using only bone cement (BC) versus only autologous material (AM) or combined materials (CM) with both bone cement and autologous material.Retrospective Chart Review.Tertiary Care Hospital.Forty-three adult patients undergoing transmastoid repair of spontaneous middle fossa CSF leak between 2014 and 2020 (BC:12, AM:15, CR:16).Cortical mastoidectomy, identification of defect, and repair with BC (Cranios® hydroxyapatite), AM (local bone, fascia, fat, and/or cartilage), or CM (Cranios® combined with autologous materials).Successful repair without recurrent CSF leak or encephalocele throughout follow up.Fifty-one percent of subjects were female. Mean age at repair was 58.6 years (SD 10.9). Mean BMI was 35.4 (SD 7.6; BC:36.3, AM:36.5, CM:33.6). Forty (93%) patients had successful repair without known recurrent CSF leak or encephalocele since surgery (BC:11, 91.6%; AM:14, 93.3%; CM:15, 93.8%; p = 0.49) over a mean length of follow up of 49.6 months (BC: 37.9, AM: 59.2, CR: 49.5). The difference in mean operative time amongst the groups was faster for patients using bone cement (BC: 100.2 min, AM: 182.8, CM: 133.2; p 0.00001).BC, AM, and CM techniques each demonstrate effective and sustained means of repair for middle fossa CSF leak and encephalocele, even in the presence of multiple defects. Use of isolated BC offers a significant decrease in operative time with a noninferior outcome. Active CSF leak at the time of surgery is associated with increased risk of recurrence.

We present an unusual case of chordoma arising entirely from the lateral skull base with imaging features suggestive of a paraganglioma. Clinical history, management, histopathology, and imaging characteristics are described, including a review of gallium-dotate PET scanning somatostatinreceptor-positive tumors. We further provide a review of management options, including a summary of our approach with surgical biopsy via retrosigmoid and resection via transtemporal approaches. Based on radiologic characteristics and location, lateral skull base chordoma may arise with isolated lateral skull base involvement and has the potential to be misidentified as a glomus jugulare on initial workup.

Gas reactions studied by in situ electron microscopy can be used to capture the real-time morphological and microchemical transformations of materials at length scales down to the atomic level. In situ closed-cell gas reaction (CCGR) studies performed using (scanning) transmission electron microscopy (STEM) can separate and identify localized dynamic reactions, which are extremely challenging to capture using other characterization techniques. For these experiments, we used a CCGR holder that utilizes microelectromechanical systems (MEMS)-based heating microchips (hereafter referred to as "E-chips"). The experimental protocol described here details the method for performing in situ gas reactions in dry and wet gases in an aberration-corrected STEM. This method finds relevance in many different materials systems, such as catalysis and high-temperature oxidation of structural materials at atmospheric pressure and in the presence of various gases with or without water vapor. Here, several sample preparation methods are described for various material form factors. During the reaction, mass spectra obtained with a residual gas analyzer (RGA) system with and without water vapor further validates gas exposure conditions during reactions. Integrating an RGA with an in situ CCGR-STEM system can, therefore, provide critical insight to correlate gas composition with the dynamic surface evolution of materials during reactions. In situ/operando studies using this approach allow for detailed investigation of the fundamental reaction mechanisms and kinetics that occur at specific environmental conditions (time, temperature, gas, pressure), in real-time, and at high spatial resolution.

Gas reactions studied by in situ electron microscopy can be used to capture the real-time morphological and microchemical transformations of materials at length scales down to the atomic level. In situ closed-cell gas reaction (CCGR) studies performed using (scanning) transmission electron microscopy (STEM) can separate and identify localized dynamic reactions, which are extremely challenging to capture using other characterization techniques. For these experiments, we used a CCGR holder that utilizes microelectromechanical systems (MEMS)-based heating microchips (hereafter referred to as "E-chips"). The experimental protocol described here details the method for performing in situ gas reactions in dry and wet gases in an aberration-corrected STEM. This method finds relevance in many different materials systems, such as catalysis and high-temperature oxidation of structural materials at atmospheric pressure and in the presence of various gases with or without water vapor. Here, several sample preparation methods are described for various material form factors. During the reaction, mass spectra obtained with a residual gas analyzer (RGA) system with and without water vapor further validates gas exposure conditions during reactions. Integrating an RGA with an in situ CCGR-STEM system can, therefore, provide critical insight to correlate gas composition with the dynamic surface evolution of materials during reactions. In situ/operando studies using this approach allow for detailed investigation of the fundamental reaction mechanisms and kinetics that occur at specific environmental conditions (time, temperature, gas, pressure), in real-time, and at high spatial resolution.

Objective To perform a systematic review of sensorineural hearing loss (SNHL) in hematologic malignancy; to describe an illustrative case of urgent cochlear implantation for bilateral profound SNHL and vestibular hypofunction in hyperviscosity syndrome; to suggest an approach to management of hyperviscosity syndrome-associated deafness with cochlear implantation. Data sources Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, systematic search of PubMed and Embase databases was undertaken for articles detailing clinical information about SNHL caused directly by hematologic malignancies. Results A total of 37 studies from 1989 to 2020 were qualitatively reviewed, the majority of which were case studies or case series. Causes of hearing loss in hematologic malignancy were found to include hyperviscosity syndrome, labyrinthine hemorrhage, infiltration, and infection. Patients with profound SNHL in hematologic malignancies from hyperviscosity syndrome may be candidates for cochlear implantation, and are also at increased risk for cochlear ossification. We review previous cases for their diagnostic approach, treatment paradigm, and outcomes data, and propose an approach to management. Conclusion Bilateral sudden profound SNHL and vestibular hypofunction is a presenting symptom of hyperviscosity syndrome in hematologic malignancy. Although this entity is rare and previous reports have suggested improvement in hearing with oncologic treatment, cases with profound hearing loss are unlikely to recover serviceable hearing. We advocate for early magnetic resonance imaging with attention to fluid signal in the inner ear and serial audiometric follow-up to guide clinical decisions. We advise early consideration for cochlear implantation.

OBJECTIVE To identify redundancy in the cochlear implant candidacy evaluation and assess its financial impact. STUDY DESIGN Retrospective chart review. SETTING Tertiary care academic cochlear implant center. PATIENTS One hundred thirty-five patients referred for cochlear implant candidacy evaluation from 2004 through 2019. INTERVENTION Community and academic audiometry were compared in a matched-pair analysis. MAIN OUTCOME MEASURES Pure-tone audiometry and word recognition scores (WRS) were compared using the Wilcoxon signed-rank test. Cost of repeated audiometry was estimated using the Medicare Provider Utilization and Payment data. RESULTS The majority of pure-tone thresholds (PTT) and pure-tone averages (PTA) had no statistically significant differences between community and academic centers. Only air PTT at 2000 Hz on the right and air PTA on the right demonstrated differences with α = 0.05 after Bonferroni correction. Despite statistical differences, mean differences in PTT and PTA were all under 3.5 dB. WRS were on average lower at the academic center, by 14.7% on the right (p

To evaluate the presence of bitter taste receptors (T2Rs) in the middle ear and to examine their relationship with chronic ear infections.Cross-sectional study.Tertiary care hospital.This study enrolled 84 patients being evaluated for otologic surgery: 40 for chronic otitis media (COM) and 44 for other surgical procedures (controls). We collected a small piece of mucosa from 14 patients for mRNA analysis and from 23 patients for immunohistochemistry. A total of 55 patients underwent a double-blind taste test to gauge sensitivity to phenylthiocarbamide, denatonium, quinine, sucrose, and sodium chloride; 47 patients gave a salivary sample for single-nucleotide polymorphism analysis of rs1376251 (Bitter taste receptors were found in all samples, but the repertoire varied among patients. T2R50 was the most consistently identified receptor by mRNA analysis. Its rs1376251 allele was related to susceptibility to COM but not the expression pattern of T2R50. Ratings of bitterness intensity of phenylthiocarbamide, a ligand for T2R38, differed significantly between the COM and control groups.T2Rs were found within the middle ear of every patient sampled; the rs1376251 allele of

The Giant Magellan Telescope (GMT), one of three next-generation extremely large telescopes (ELTs), will have a 25.4- meter diameter effective aperture, and will be located on the summit of Cerro Las Campanas in Chile. Developing a new observatory for cutting-edge science operations and a 50-year lifespan poses a variety of design challenges. This paper discusses the designs that have been adopted in the GMT site master plan, including designs for the site infrastructure, telescope enclosure, and facilities. The GMTO site has been in active construction since 2015, and in the past two years has completed important steps in site development including completion of hard rock excavations for the telescope and enclosure foundations, construction of the underground utility distribution systems, and other infrastructure upgrades to support the current and upcoming construction work.

Protocols for conducting in situ transmission electron microscopy (TEM) reactions using an environmental TEM with dry gases have been well established. However, many important reactions that are relevant to catalysis or high-temperature oxidation occur at atmospheric pressure and are influenced by the presence of water vapor. These experiments necessitate using a closed-cell gas reaction TEM holder. We have developed protocols for introducing and controlling water vapor concentrations in experimental gases from 2% at a full atmosphere to 100% at ~17 Torr, while measuring the gas composition using a residual gas analyzer (RGA) on the return side of the in situ gas reactor holder. Initially, as a model system, cube-shaped MgO crystals were used to help develop the protocols for handling the water vapor injection process and confirming that we could successfully inject water vapor into the gas cell. The interaction of water vapor with MgO triggered surface morphological and chemical changes as a result of the formation of Mg(OH)2, later validated with mass spectra obtained with our RGA system with and without water vapor. Integrating an RGA with an in situ scanning/TEM closed-cell gas reaction system can thus provide critical measurements correlating gas composition with dynamic surface restructuring of materials during reactions.

OBJECTIVE To evaluate factors influencing the development of nonauditory percepts and facial nerve stimulation after cochlear implant (CI) activation. STUDY Retrospective cohort study. SETTING Tertiary referral center. PATIENTS Over the course of 5 years, 433 consecutive patients were evaluated for CI and 518 ears were implanted. Of those, 497 ears had information regarding CI activation. INTERVENTIONS Lateral wall electrodes (LWE) or perimodiolar/mid-scalar electrodes (PME) were used during implantation. PRIMARY OUTCOME MEASURE Nonauditory percepts and facial nerve stimulation after activation of CI. RESULTS Among the 497 devices, which were activated at our institution, 357 (72%) had LWE while 140 (28%) patients had a PME. Of the patients with LWE, 49 (13.7%) patients experienced some form of nonauditory percept. In comparison, 11 (9.2%) patients with a PME had some form of nonauditory percept (p

Tuberculosis (TB) is a leading cause of childhood mortality. Isoniazid preventive therapy significantly reduces progression to TB disease. The World Health Organization recommends that high TB burden countries conduct child contact management (CCM) to identify exposed child contacts aged5 years for screening and appropriate treatment. An active, clinic-based CCM strategy incorporating transport/screening reimbursement, monitoring and evaluation tools, and health care worker education was implemented in western Kenya. Among 169 identified child contacts aged5 years, 146 (86%) underwent successful screening, of whom 43 (29%) were diagnosed with active TB. We describe our CCM strategy and its potential for enhancing screening and treatment efforts.La tuberculose (TB) est une cause majeure de mortalité des enfants. Le traitement préventif par isoniazide réduit significativement la progression vers la TB maladie. L'Organisation Mondiale de la Santé recommande aux pays durement frappés par la TB de réaliser une prise en charge des enfants contacts (CCM) afin d'identifier les enfants contacts âgés de5 ans exposés en vue d'un dépistage et d'un traitement appropriés. Une stratégie active de CCM basée sur la clinique incorporant le transport/le remboursement du dépistage, les outils de suivi et évaluation et l'éducation du personnel de santé a été mise en œuvre dans l'Ouest du Kenya. Sur 169 enfants contacts identifies âgés de5 ans, 146 (86%) ont eu un dépistage réussi, dont 43 (29%) ont eu un diagnostic de TB active. Nous décrivons notre stratégie de CCM et son potentiel d'aMEacute;lioration des efforts de dépistage et de traitement.La tuberculosis (TB) es una causa mayor de mortalidad en la niñez. El tratamiento preventivo con isoniazida disminuye de manera considerable la progresión hacia la enfermedad activa. La Organización Mundial de la Salud recomienda a los países con alta carga de morbilidad por TB que practiquen la gestión de los contactos pediátricos (CCM), con el fin de reconocer a los niños menores de 5 años de edad expuestos, realizar la detección de la TB y ofrecer el tratamiento apropiado. En Kenya occidental se introdujo en los consultorios una estrategia activa de gestión de los contactos pediátricos, que comportaba el reembolso de los gastos de transporte y detección, instrumentos de supervisión y evaluación y educación de los profesionales de salud. De los 169 contactos pediátricos menores de 5 años de edad encontrados, se practicó una detección adecuada en 146 (86%) y se diagnosticó TB activa en 43 (29%). En el presente artículo se describe la estrategia CCM y se analiza su capacidad para fortalecer los esfuerzos de detección sistemática y tratamiento.

Objective Gamma Knife stereotactic radiosurgery (GK-SRS) is a preferred treatment option for tumors of the jugular foramen. We hypothesized that GK-SRS toxicity is higher for lower cranial nerve schwannomas than for glomus jugulare tumors despite anatomically similar locations. Methods We performed a retrospective review of all patients who received GK-SRS for glomus jugulare tumors and lower cranial nerve schwannomas at our institution between 2006 and 2014. Because of small sample sizes, Fisher's exact tests and logistic regression techniques were employed using SPSS. Result We identified 20 glomus jugulare tumors and 6 lower cranial nerve schwannoma patients with a median follow-up of 17 months. Median marginal dose was 16 Gy (range 13–18 Gy) and 12.5 Gy (range 12–14 Gy), respectively. All except one patient had tumor control at last follow-up visit. No worsening of pre-existing neurological deficits was observed. There were seven patients who developed any new neurological deficit after GK-SRS, four from the glomus group, and three from the schwannoma group (20 and 50% of each group, respectively). Only two of seven patients had permanent new neurological deficits. Both of them were in the schwannoma group. Univariate analysis showed that only a diagnosis of schwannoma had a greater risk of permanent new cranial nerve complication after GK-SRS compared with diagnosis of glomus jugulare (p = 0.046). Conclusion Although the marginal dose for glomus jugulare is greater, our study suggests that the risk of a new permanent neurological deficit after GK-SRS was higher in the schwannoma group compared with the glomus group.

Objective: To demonstrate the safety and effectiveness of the MED-EL Electric-Acoustic Stimulation (EAS) System, for adults with residual low-frequency hearing and severe-to-profound hearing loss in the mid to high frequencies. Study Design: Prospective, repeated measures. Setting: Multicenter, hospital. Patients: Seventy-three subjects implanted with PULSAR or SONATA cochlear implants with FLEX24 electrode arrays. Intervention: Subjects were fit postoperatively with an audio processor, combining electric stimulation and acoustic amplification. Main Outcome Measures: Unaided thresholds were measured preoperatively and at 3, 6, and 12 months postactivation. Speech perception was assessed at these intervals using City University of New York sentences in noise and consonant–nucleus–consonant words in quiet. Subjective benefit was assessed at these intervals via the Abbreviated Profile of Hearing Aid Benefit and Hearing Device Satisfaction Scale questionnaires. Results: Sixty-seven of 73 subjects (92%) completed outcome measures for all study intervals. Of those 67 subjects, 79% experienced less than a 30 dB HL low-frequency pure-tone average (250–1000 Hz) shift, and 97% were able to use the acoustic unit at 12 months postactivation. In the EAS condition, 94% of subjects performed similarly to or better than their preoperative performance on City University of New York sentences in noise at 12 months postactivation, with 85% demonstrating improvement. Ninety-seven percent of subjects performed similarly or better on consonant–nucleus–consonant words in quiet, with 84% demonstrating improvement. Conclusion: The MED-EL EAS System is a safe and effective treatment option for adults with normal hearing to moderate sensorineural hearing loss in the low frequencies and severe-to-profound sensorineural hearing loss in the high frequencies who do not benefit from traditional amplification.

Objective Evaluate the incidence of and potential contributory factors to facial nerve paresis and other cranial neuropathies (CN) following stereotactic radiosurgery with Gamma Knife (GK) for primary treatment of vestibular schwannoma (VS). Study design Retrospective chart review. Setting Tertiary referral center. Patients Charts were reviewed for all adult patients receiving primary GK treatment for unilateral VS between 2005 and 2013. Patients with NF2 or previous surgery were excluded from analysis. Intervention GK radiosurgery. Main outcome measures The incidence of new-onset facial nerve paresis after primary GK treatment of VS was evaluated. Secondary endpoints included other cranial neuropathies. Results One hundred thirty-three patients with VS received primary GK therapy. Posttreatment CN developed in 33 patients (24.8%). Twelve patients (9.0%) experienced trigeminal paresthesia, 11 (8.3%) developed sudden sensorineural hearing loss (SSNHL) requiring steroids, and seven (5.3%) demonstrated facial paresis. The mean maximum cochlear dose was 15.49 Gy in patients with facial paresis compared with 12.42 Gy in subjects without facial paresis (p = 0.032). Subjects with facial paresis were more likely to have a lateral tumor without fundal fluid on magnetic resonance imaging (MRI) (71%) compared with subjects without facial paresis (43%). Conclusions In the treatment of VS with primary GK, maximum cochlear dose was significantly associated with facial paresis. Laterally extending tumors without fundal fluid on MRI experienced higher rates of facial paresis. These factors should be considered during GK treatment planning for VS.

To assess how pretreatment vestibular schwannoma (VS) tumor characteristics are associated with vestibular symptoms after gamma knife (GK) surgery.Retrospective chart review of patients undergoing GK treatment for VS at our institution from 2005 to 2018.Academic tertiary referral center.Patients receiving primary GK surgery for vestibular schwannomas with at least 6 months of follow up. Patients with neurofibromatosis 2 or previous surgery were excluded.The presence of posttreatment vestibular symptoms within 6 months after GK. Clinical records were assessed for pretreatment tumor, patient, and treatment characteristics that impacted posttreatment symptoms.All patients received radiation doses between 12 and 13 Gy. Of 115 patients, the average age was 60. Thirty-seven (32%) patients developed vestibular symptoms within 6 months post-GK, and 18 patients were referred for vestibular rehabilitation. Ten of 13 patients undergoing vestibular rehabilitation reported improvement. Overall, 112 patients had tumor measurements. Pretreatment tumors were significantly smaller for patients with acute vestibular symptoms (mean 1.43 cm versus 1.71 cm, p = 0.007). On multivariate analysis, smaller tumor size (p = 0.009, odds ratio [OR] = 0.29, 95% confidence interval [CI] [0.12-0.73]) was significantly associated with vestibular symptoms within 6 months of GK. Patients with tumors less than 1.6 cm were more likely to receive referrals for vestibular rehabilitation within 6 months posttreatment (25% versus 9.4%, p = 0.026, OR = 3.22, 95% CI [1.00, 11.32]).Smaller vestibular schwannomas were significantly associated with higher rates of post-GK vestibular symptoms. Pretreatment tumor size may be used to counsel patients on the likelihood of post-GK vestibular symptoms and vestibular rehabilitation.

Particulars are to be understood by contrasting them with universals, that term being used to comprise both properties and relations. Often the term ‘individuals’ is used interchangeably with ‘particulars’, though some restrict the term ‘individuals’ to those particulars whose existence has more than momentary duration. It is sometimes taken as a distinctive feature of particulars that they cannot be in more than one place at a time, whereas universals are capable of being wholly present in more than one place at a given time: if you have a white thing here and a white thing there, then you have two particulars but only one property. This way of distinguishing between particulars and universals may help us to focus on apt paradigm cases of each, but arguably this does not get us to the heart of the matter. On the one hand, some think it is possible, at least in principle, for a magician, or Pythagoras, or a time traveller, or a subatomic particle to be in two places at once, even though each is a particular. On the other hand, some think that there are properties which could not possibly be manifested in two different places at the same time, and yet which nonetheless are universals: think, for instance, of the divine property of absolute perfection, or of the conjunction of all intrinsic properties of a Leibnizian monad (or possible world); or of Judas’ property of simply being Judas. Particulars are things which have properties and which stand in relations – particulars ‘instantiate’ properties and relations. By itself, however, this does not distinguish particulars from universals since universals, too, are naturally thought to have properties and to stand in relations. What distinguishes particulars is the fact that, while a particular instantiates properties and relations, nothing instantiates a particular. Universals both ‘have’ (properties and relations) and are ‘had’; particulars ‘have’ but are not ‘had’. Since a particular is not instantiated by another thing, it is sometimes said to exist ‘in itself’, whereas a universal exists ‘in’ something else. For this reason, the term ‘particular’ is related to the term ‘substance’, which is traditionally used to mean something capable of independent existence.

In metaphysics, the term ‘universals’ is applied to things of two sorts: properties (such as redness or roundness), and relations (such as kinship relations like sisterhood, or the causal relation, or spatial and temporal relations). Universals are to be understood by contrast with particulars. Few universals, if any, are truly ‘universal’ in the sense that they are shared by all individuals – a universal is characteristically the sort of thing which some individuals may have in common, and others may lack. Universals have been conceived to be things which enable us intellectually to grasp a permanent, underlying order behind the changing flux of experience. Some of the gods of ancient mythologies correspond roughly to various important underlying universals – social relations for instance, as for example if Hera is said to be the goddess of Marriage and Ares (or Mars) is said to be the god of War. Many traditions, East and West, have dealt with the underlying problem which generates theories of universals; nevertheless the term ‘universals’ is closely tied to the Western tradition, and the agenda has been set largely by the work of Plato and Aristotle. The term often used in connection with Plato is not ‘universals’ but ‘Forms’ (or ‘Ideas’, used in the sense of ideals rather than of thoughts), the term ‘universals’ echoing Aristotle more than Plato. Other terms cognate with universals include not only properties and relations, but also qualities, attributes, characteristics, essences and accidents (in the sense of qualities which a thing has not of necessity but only by accident), species and genus, and natural kinds. Various arguments have been advanced to establish the existence of universals, the most memorable of which is the ‘one over many’ argument. There are also various arguments against the existence of universals. There are, for instance, various vicious regress arguments which derive from Aristotle’s so-called ‘third man argument’ against Plato. Another family of arguments trades on what is called Ockham’s razor: it is argued that we can say anything we need to say, and explain everything we need to explain, without appeal to universals; and if we can, and if we are rational, then we should. Those who believe in universals are called Realists, those who do not are called Nominalists.

In the social sciences, functionalists are theorists who give an especially prominent role to functional explanations. One of the most influential self-defined functionalists, Malinowski (1926), summed up this view: the functionalist ‘insists… upon the principle that in every type of civilisation, every custom, material object, idea and belief fulfils some vital function, has some task to accomplish, represents an indispensable part within a working whole’. As an example of a functionalist explanation, one might consider the hypothesis, as argued for instance by Evans-Pritchard in his work on the Azande in Africa, that belief in witches generally plays a role in maintaining social stability (1937). In the last few decades of the twentieth century, postmodern, or post-structuralist, sociologists have largely disavowed the pursuit of functional explanations. The extremism of some functionalist theses has been matched by an equal extremism in postmodern antitheses. In denying that everything must be explained functionally, some go so far as to say that nothing should ever be explained functionally. Yet there is liveable logical space between the modernist’s ‘There has always got to be a reason, the real reason, for everything’, and the postmodernist’s ‘There is never any real reason for anything’. We do not have to be card-carrying functionalists to suspect that functional explanations might be found for at least some of the bewildering things that some people do in various parts of the world. New models of functional explanation are emerging from recent ferment in the biological sciences, and these new models may suggest new ways of approaching functional explanations in the social sciences.

A detailed Computational Fluid Dynamics (CFD) model for the Giant Magellan Telescope (GMT) telescope has been developed and used to simulated and analyze the aero-optical environment around the observatory. The developed model accounts for the major observatory components such as the primary (M1) and secondary (M2) mirrors, the M2 supporting truss, other subcomponents of the telescope mount, and enclosure building along with the auxiliary and site support buildings on the summit. A large topographical area around the installation site is included. This study evaluates three different lower enclosure designs; a closed soffit, an open soffit and a perforated ring-wall (partially closed soffit). Timevarying CFD simulations provide detailed flow and temperature fields along the optical path, which are subsequently used to compute optical parameters such as Optical Path Difference (OPD) maps and Point Source Sensitivity normalized (PSSn), the GMT Image Quality (IQ) metric. Results show that enclosure-induced turbulent flow patterns and refractive index variations have a greater influence on optical performance compared to flow and thermal behavior external to the enclosure. Instantaneous and mean PSSn values obtained for the three soffit configurations show minor differences, indicating that the lower enclosure design has minimal impact on observatory optical performance for the simulated operating conditions.

The Giant Magellan Telescope (GMT) is currently planned for construction at Las Campanas Peak in northern Chile. Part of the next generation of extremely large telescopes, GMT will be one of the most powerful ground-based telescopes in operation in the world. Due to the larger aperture envisioned for GMT, characterization and control of the air flow entering and circulating within the enclosure will be required to maintain the highest possible image quality. Aero-thermal interactions between the site topography, enclosure, internal systems, and optics are complex. A key parameter for image quality is the thermal gradient between the terrain and the air mass entering the enclosure, and how quickly that gradient can be dissipated to equilibrium. Because the thermal gradients are highest near the ground, an important function of the GMT enclosure is to minimize the flow of ground-layer air entering the enclosure. By doing so, a more uniform air density above the telescope will enable higher image quality. The design of the GMT lower enclosure is driven by equipment storage and access requirements but also directly impacts the origin and quality of the air entering the enclosure aperture. To ensure the highest quality GMT optical performance, Computational Fluid Dynamics (CFD) models and specialized analyses are utilized to evaluate several lower enclosure designs for their ability to limit the amount of ground-layer air entering the enclosure aperture. Lower enclosure designs with traditional solid outer walls promote the formation of “necklace” vortices, which tend to direct near-surface air, containing steep thermal gradients, into the enclosure aperture, potentially reducing image quality. Modifications to the lower enclosure, such as perforating the outer walls, are shown to suppress these necklace vortices at the expense of added structural complexity and/or reduced internal storage space. Initial isothermal CFD simulations defined the minimum height above terrain reached by the flow-path upwind of the observatory as a proxy to characterize the quality of air entering the enclosure, with lower heights associated with steeper thermal gradients. Based on these results, the most promising designs are further refined and subjected to additional higher fidelity CFD analyses, which includes a terrestrial thermal boundary layer. These simulations are also surveyed to quantify the aero-thermal environment along telescope optical paths, permitting evaluation and comparison of the predicted optical performance of the final candidate enclosure designs. Results from preliminary water tunnel testing of select lower-enclosure designs have increased our confidence in the CFD simulations.

The Giant Magellan Telescope (GMT), one of three next-generation extremely large telescopes (ELTs), will have a 25.4- meter diameter effective aperture, and will be located on the summit of Cerro Las Campanas in Chile. Developing a new observatory for cutting-edge science operations and a 50-year lifespan poses challenges that have resulted in competing design concepts. This paper discusses the concepts that have been adopted in the GMT site master plan, including designs for the site infrastructure, telescope enclosure, and facilities. The GMTO site has been in active construction since 2015, and in the past two years has completed important steps in site development including completion of residential and office facilities, road improvements, and other necessary infrastructure to support upcoming work. This paper concludes with an overview on managing design and construction simultaneously.

The Giant Magellan Telescope (GMT) is an Extremely Large Telescope (ELT) class observatory set to make history as one of the largest telescopes ever built. Vast improvements in the fields of optics, control systems, and mirror fabrication technologies have facilitated correspondingly drastic increases in the size and presence of ground-based telescopes previously thought to be impossible. Size for these observatories has increased to the point where conventional approaches impart seismic demands on the telescope structure and optics that are unmanageable. With this, a refined approach involving base isolation is being designed to provide seismic protection of a sensitive, invaluable instrument that will revolutionize our understanding of the universe.

Intracranial dural arteriovenous fistulae (DAVF) are rare vascular malformations. They are generally considered to be acquired lesions, often attributed to dural sinus thrombosis and intracranial venous hypertension. The authors encountered a case of DAVF associated with an octreotide-positive vestibular schwannoma. A 46-year-old female had symptoms of right ear congestion accompanied by pulsatile tinnitus and mild hearing loss. Magnetic resonance imaging (MRI) identified a lobulated mass centered at the cerebellopontine angle. Preoperatively, on cerebral angiography, there was an incidental discovery of a DAVF in the right posterior fossa. The decision was made to proceed with resection of the tumor in a staged fashion. Her latest follow-up MRI showed no evidence of recurrent tumor. This is the second reported case of DAVF associated with an intracranial schwannoma. Findings are discussed along with a thorough review of the literature. This case, combined with the data from the literature review, led us to believe that tumor-related angiogenesis might contribute to DAVF formation.

The strength of CH–aryl interactions (ΔG) in 14 solvents was determined via the conformational analysis of a molecular torsion balance. The molecular balance adopted folded and unfolded conformers in which the ratio of the conformers in solution provided a quantitative measure of ΔG as a function of solvation. While a single empirical solvent parameter based on solvent polarity failed to explain solvent effect in the molecular balance, it is shown that these ΔG values can be correlated through a multiparameter linear solvation energy relationship (LSER) using the equation introduced by Kamlet and Taft. The resulting LSER equation [ΔG = −0.24 + 0.23α − 0.68β − 0.1π* + 0.09δ]—expresses ΔG as a function of Kamlet–Taft solvent parameters—revealed that specific solvent effects (α and β) are mainly responsible for “tipping” the molecular balance in favour of one conformer over the other, where α represents a solvents' hydrogen-bond acidity and β represents a solvents' hydrogen-bond basicity. Furthermore, using extrapolated data (α and β) and the known π* value for the gas phase, the LSER equation predicted ΔG in the gas phase to be −0.31 kcal mol−1, which agrees with −0.35 kcal mol−1 estimated from DFT-D calculations.