630,384 Works

Two-Layer Geostrophic Vortex Dynamics. Part 2. Alignment and Two-Layer V-States

Lorenzo M. Polvani
The process of alignment, a new fundamental interaction between vortices in a stratified and rapidly rotating fluid, is defined and studied in detail in the context of the two-layer quasi-geostrophic model. Alignment occurs when two vortices in different density layers coalesce by reducing their horizontal separation. It is found that only vortices whose radii are comparable with or larger than the Rossby deformation radius can align. In the same way as the merger process (in...

Filamentation of Unstable Vortex Structures via Separatrix Crossing: A Quantitative Estimate of Onset Time

Lorenzo M. Polvani, G. R. Flierl & N. J. Zabusky
The onset of filamentation for compact vortex structures in two-dimensional incompressible flows is elucidated. An estimate is presented for the filamentation time of an unstably perturbed Kirchhoff ellipse, obtained from a linear analysis of the geometry of the instantaneous corotating streamfunction.

The Effect of Dissipation on Spatially Growing Nonlinear Baroclinic Waves

Lorenzo M. Polvani & J. Pedlosky
The question of convective (i.e., spatial) instability of baroclinic waves on an f-plane is studied in the context of the two-layer model. The viscous and inviscid marginal curves for linear convective instability are obtained. The finite-amplitude problem shows that when dissipation is O(1) it acts to stabilize the waves that are of Eady type. For very small dissipation the weakly nonlinear analysis reveals that at low frequencies, contrary to what is known to occur in...

Delayed Southern Hemisphere Climate Change Induced by Stratospheric Ozone Recovery, as Projected by the CMIP5 Models

Elizabeth A. Barnes, Nicholas W. Barnes & Lorenzo M. Polvani
Stratospheric ozone is expected to recover by the end of this century due to the regulation of ozone depleting substances by the Montreal Protocol. Targeted modeling studies have suggested that the climate response to ozone recovery will greatly oppose the climate response to rising greenhouse-gas (GHG) emissions. However, the extent of this cancellation remains unclear since only a few such studies are available. Here, we analyze a much larger set of simulations performed for the...

Effects of seawater-pH and biomineralization on the boron isotopic composition of deep-sea bamboo corals

Jesse Robert Farmer, Baerbel Hoenisch, Laura F. Robinson & Tessa M. Hill
The ocean is currently absorbing excess carbon from anthropogenic emissions, leading to reduced seawater-pH (termed ‘ocean acidification’). Instrumental records of ocean acidification are unavailable from well-ventilated areas of the deep ocean, necessitating proxy records to improve spatio-temporal understanding on the rate and magnitude of deep ocean acidification. Here we investigate boron, carbon, and oxygen isotopes on live-collected deep-sea bamboo corals (genus Keratoisis) from a pHtot range of 7.5–8.1. These analyses are used to explore the...

Improving the detection and tracking of tropical cyclones in atmospheric general circulation models

Suzana J. Camargo & Stephen E. Zebiak
Dynamical seasonal forecasts of tropical storm frequency require robust and efficient algorithms for detection and tracking of tropical storms in atmospheric general circulation models (AGCMs). Tropical storms are generally detected when dynamic and thermodynamic variables meet specified criteria. Here, it is shown that objectively defined model- and basin-dependent detection criteria improve simulations of tropical storm climatology and interannual variability in low-resolution AGCMs. An improved tracking method provides more realistic tracking and accurate counting of storms.

Beyond the Threshold: Conformity, Resistance, and the ACRL Information Literacy Framework for Higher Education

Ian G. Beilin
The recently adopted ACRL Framework for Information Literacy for Higher Education has generated much critique and discussion, including many important reflections on the nature of information literacy and librarianship itself. This article provides a brief consideration of some of these responses and as well a critique of the Framework from the perspective of critical information literacy. It argues that although the Framework demonstrably opens up possibilities for an information literacy instruction that encourages students to...

Functional Aspects of Gait in Essential Tremor: A Comparison with Age-Matched Parkinson’s Disease Cases, Dystonia Cases, and Controls

Elan D. Louis & Ashwini K. Rao
Background: An understanding of the functional aspects of gait and balance has wide ramifications. Individuals with balance disorders often restrict physical activity, travel, and social commitments to avoid falling, and loss of balance confidence, itself, is a source of disability. We studied the functional aspects of gait in patients with essential tremor (ET), placing their findings within the context of two other neurological disorders (Parkinson’s disease [PD] and dystonia) and comparing them with age‐matched controls....

Pseudodystonic Posture Secondary to Klippel–Feil Syndrome and Diastematomyelia

Martin Lopez-Vicchi, Gustavo Da Prat & Emilia Mabel Gatto
Background: Dystonic postures possess a great number of differential diagnoses. Phenomenology Shown: We describe a pseudodystonic posture in a 61‐year‐old woman with skeletal and extra‐skeletal abnormalities. Educational Value: Klippel–Feil syndrome represents an unusual cause of pseudodystonic posture to be considered in the differential diagnosis of dystonia.

Feasibility study for downscaling seasonal tropical cyclone activity using the NCEP regional spectral model

Suzana J. Camargo, Huilan Li & Liqiang Sun
The potential use of the National Centers for Environmental Prediction (NCEP) Regional Spectral Model (RSM) for downscaling seasonal tropical cyclone (TC) activity was analyzed here. The NCEP RSM with horizontal resolution of 50 km, was used to downscale the ECHAM4.5 Atmospheric General Circulation Model (AGCM) simulations forced with observed sea surface temperature (SST) over the western North Pacific. An ensemble of ten runs for June–November 1994 and 1998 was studied. The representation of the TCs...

Diagnosis of the MJO Modulation of Tropical Cyclogenesis Using an Empirical Index

Suzana J. Camargo, Matthew C. Wheeler & Adam H. Sobel
The modulation of tropical cyclone activity by the Madden-Julian oscillation (MJO) is explored using an empirical genesis potential (GP) index. Composite anomalies of the genesis index associated with the different MJO phases are consistent with the composite anomalies in TC genesis frequency that occur in the same phases, indicating that the index captures the changes in the environment that are at least in part responsible for the genesis frequency changes. Of the four environmental variables...

Significant Properties of Complex Digital Artifacts: Open Issues from a Video Game Case Study

Simone Sacchi
In this poster we present the preliminary output of a study meant to analyze the applicability of the InSPECT Assessment Framework to a particular kind of complex digital artifact: video games. We discuss open issues and possible improvements in the assessment workflow.

Increase in Diarrheal Disease Associated with Arsenic Mitigation in Bangladesh

Jianyong Wu, Yasuyuki Akita Jahangir Alam, Alexander Van Geen, Kazi Matin Ahmed, Patricia J. Culligan, Veronica Escamilla, John Feighery, Andrew S. Ferguson, Peter Knappett, Brian J. Mailloux, Larry D. McKay, Marc L. Serre, P. Kim Streatfield, Mohammad Yunus & Michael Emch
Background: Millions of households throughout Bangladesh have been exposed to high levels of arsenic (As) causing various deadly diseases by drinking groundwater from shallow tubewells for the past 30 years. Well testing has been the most effective form of mitigation because it has induced massive switching from tubewells that are high (>50 µg/L) in As to neighboring wells that are low in As. A recent study has shown, however, that shallow low-As wells are more...

Indigenous Peoples’ Access to Justice, Including Truth and Reconciliation Processes

Access to justice is a demand that increasingly underlies the major debates of our time, whether in the area of economic, political and social development, peace, human rights or culture. The issue is a bridge between the past, the present and the future as it refers to the entrenched marginalization of and systemic discrimination against members or groups of society. Access to justice is the stepping stone to address or remedy injustice. No area of...

In the War but Not of the War: The Protestant Public Sphere in WW-II-era China

Amy R. M. O'Keefe
Many thanks for a very fruitful trip to Columbia University’s Burke Library. Helpful staff enabled me to maximize my productivity during the short time I was there, and I came away thrilled with what I was able to accomplish. While in New York I went through a large amount of the materials in the National Christian Council of China papers, took photos of relevant items for future perusal, and obtained digital copies of much of...

Recognizing Uncommon Presentations of Psychogenic (Functional) Movement Disorders

José Fidel Baizabal-Carvallo & Robert Fekete
Background: Psychogenic or functional movement disorders (PMDs) pose a challenge in clinical diagnosis. There are several clues, including sudden onset, incongruous symptoms, distractibility, suggestibility, entrainment of symptoms, and lack of response to otherwise effective pharmacological therapies, that help identify the most common psychogenic movements such as tremor, dystonia, and myoclonus. Methods: In this manuscript, we review the frequency, distinct clinical features, functional imaging, and neurophysiological tests that can help in the diagnosis of uncommon presentations...

Prevalence of Essential Tremor on Arosa Island, Spain: a Community-based, Door-to-Door Survey

Manuel Seijo-Martinez, Maria Castro Del Rio, Jose Ramon Rodriguez Alvarez, Ramon Suarez-Prado, Eugenio Torres Salgado, Javier Paz Esquete & Maria Jesus Sobrido-Gomez
Background: The prevalence of essential tremor (ET) is still not well understood and the various studies performed to date have generated highly variable results. Few epidemiologic studies on the prevalence of ET have been reported from Spain. Methods: A one‐stage door‐to‐door survey was conducted on Arosa Island, northwestern Spain, to determine the prevalence of ET in the population aged 65 years and older. The diagnostic criteria for ET were the presence of non‐dystonic head tremor...

Hereditary Coproporphyria Associated with the Q306X Mutation in the Coproporphyrin Oxidase Gene Presenting with Acute Ataxia

Félix Javier Jiménez-Jiménez, José AG Agúndez, Carmen Martínez, Francisco Navacerrada, José Francisco Plaza-Nieto, Belén Pilo-De-La-Fuente, Hortensia Alonso-Navarro & Elena García-Martín
Background: Hereditary coproporphyria (HCPO) is a low‐penetrance, autosomal dominant, acute hepatic porphyria characterized by the overproduction and excretion of coproporphyrin. The most common neurological manifestations of this entity include peripheral, predominantly motor dysfunction, and central nervous system dysfunction. Ataxia associated with HCPO has not been reported previously. The aim of this article is to report a patient with HCPO presenting with acute ataxia. Case Report: We describe a 44‐year‐old patient presenting clinically with acute ataxia...

The Buck Stops Here: Assessing Ebook Subscriptions at Columbia University Libraries

Melissa J. Goertzen & Krystie A. Klahn
This paper builds on the ideas presented in The Future Landscape of E-Book Programs at Columbia University Libraries (Charleston Conference 2013, poster session). The objective is to describe an assessment methodology used at Columbia University Libraries which evaluated the cost-benefit of subscribed e-book collections. By appraising several databases, we were able to analyze cost and usage to determine the actual value of these resources. This work involved conducting cost and overlap analyses as well as...

Voice Handicap in Essential Tremor: A Comparison with Normal Controls and Parkinson’s Disease

Elan Daniel Louis & Marina Gerbin
Background: Although voice tremor is one of the most commonly-noted clinical features of essential tremor (ET), there are nearly no published data on the handicap associated with it. Methods: The Voice Handicap Index (VHI) was self-administered by participants enrolled in a research study at Columbia-University Medical Center. The VHI quantifies patients' perceptions of handicap due to voice difficulties. Data from 98 ET cases were compared to data from 100 controls and 85 patients with another...

The Relationship Between Parkinson's Disease and Essential Tremor: Review of Clinical, Epidemiologic, Genetic, Neuroimaging and Neuropathological Data, and Data on the Presence of Cardinal Signs of Parkinsonism in Essential Tremor

Félix Javier Jiménez-Jiménez, Hortensia Alonso-Navarro, Elena García-Martín & José A.G. Agúndez
Background: The possible relationship between essential tremor (ET) and Parkinson’s disease (PD) remains controversial since the first description of PD. However, there is increasing evidence suggesting the overlap between these two disorders. The aim of this review is to examine the relationship between PD and ET, focusing on clinical, epidemiologic, genetic, neuroimaging and neuropathological data, and the presence of cardinal symptoms of parkinsonism in ET. Methods: We conducted a PubMed search from 1966 until November...

SPG11 Presenting with Tremor

Susanne A. Schneider, Catherine J. Mummery, Mohadeseh Mehrabian, Henry Houlden & Peter G. Bain
Background: Hereditary spastic paraplegias (HSPs) are a clinically and genetically heterogeneous group of neurological diseases, which typically present with progressive lower extremity weakness and spasticity causing progressive walking difficulties. Complicating neurological or extraneurological features may be present. Case Report: We describe a 19-year-old male who was referred because of an action tremor of the hands; he later developed walking difficulties. Callosal atrophy was present on his cerebral magnetic resonance imaging scan, prompting genetic testing for...

Familial Cortical Myoclonic Tremor with Epilepsy and Cerebellar Changes: Description of a New Pathology Case and Review of the Literature

Sarvi Sharifi, Eleonora Aronica, Johannes H. T. M. Koelman, Marina A. J. Tijssen & Anne-Fleur Van Rootselaar
Background: Over 60 Asian and European families with cortical myoclonic tremor and epilepsy have been reported under various names. Cerebellar changes may be part of the syndrome. In this study, we report the neuropathology findings in a new Dutch familial cortical myoclonic tremor with epilepsy case and review the literature on this syndrome. Methods: Neuropathological investigations were performed for a third case of the Dutch pedigree. In addition, we searched the literature for pedigrees meeting...

Methodological Issues in Clinical Drug Development for Essential Tremor

Michael A. Carranza, Madeline R. Snyder, Rodger J. Elble, Angelique E. Boutzoukas & Theresa A. Zesiewicz
Essential tremor (ET) is one of the most common tremor disorders in the world. Despite this, only two medications have received Level A recommendations from the American Academy of Neurology to treat it (primidone and propranolol). Even though these medications provide relief to a large group of ET patients, up to 50% of patients are non-responders. Additional medications to treat ET are needed. This review discusses some of the methodological issues that should be addressed...

Tremor: Clinical Phenomenology and Assessment Techniques

Christopher W. Hess & Seth L. Pullman
Tremors are among the most common movement disorders. As there can be considerable variability in the manner in which clinicians assess tremor, objective quantitative tools such as electromyography, accelerometry, and computerized, spiral analysis can be very useful in establishing a clinical diagnosis and in research settings. In this review, we discuss the various methods of quantitative tremor analysis and the classification and pathogenesis of tremor. The most common pathologic tremors and an approach to the...

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