3,245 research outputs found
Providential Tides: the Double Low Water of Narragansett Bay
We investigate a mechanism for producing double-lows and double-highs in the semi-diurnal tide by selective amplification of higher harmonics in a resonant gulf. A double low water is observed at Providence, RI, near the head of Narragansett Bay on days when there is a flattening of the low water tidal curve at Newport, at the mouth of the bay. The flattening is caused by an unusually large quarter-diurnal component to the tide at Newport. The quarter diurnal component has the right phase (a maximum close to the time of the minimum in the semi-diurnal tide) to produce a prolonged flattening of the tidal curve around low water. The natural period of Narragansett Bay (for quarter-wavelength resonance) is close to 4 h and the quarter diurnal tide is amplified, relative to the semi-diurnal tide, within the bay. The selective amplification of the higher harmonic further prolongs the flattening effect at Providence and, occasionally, is sufficient to create a double low water at the head of the bay from quarter and semi-diurnal tides alone. More often, though, a sixth-diurnal harmonic produced within the bay, added to the flattened low water at Providence, creates the double low water. This mechanism of selective amplification of tidal harmonics could be relevant to double tides elsewhere
Proglucagon gene expression is regulated by a cyclic AMP-dependent pathway in rat intestine.
Crystal constructions in Number Theory
Weyl group multiple Dirichlet series and metaplectic Whittaker functions can
be described in terms of crystal graphs. We present crystals as parameterized
by Littelmann patterns and we give a survey of purely combinatorial
constructions of prime power coefficients of Weyl group multiple Dirichlet
series and metaplectic Whittaker functions using the language of crystal
graphs. We explore how the branching structure of crystals manifests in these
constructions, and how it allows access to some intricate objects in number
theory and related open questions using tools of algebraic combinatorics
Intentional Foreign Body Ingestion: A Complex Case of Pica
Intentional ingestion of foreign objects, a form of self-injurious behavior, is rarely discussed in the medical literature but often requires extensive evaluation, management, and resources. It can be especially problematic for gastroenterologists, who are often consulted for removal of the foreign body. Pica is the psychiatric diagnosis for intentional ingestion of nonnutritive objects and is most commonly seen in prison inmates and those diagnosed with intellectual disability or psychiatric illness. This case report presents a challenging case of pica, highlighting the complexity involved in diagnosis and the need for early psychiatric intervention. It also aims to provide a general review of the literature and practical recommendations to assist with managing this form of self-injurious behavior in the inpatient setting. Collaborative efforts among specialties in addition to primary prevention are vital to successful management of these patients
Metaplectic Ice
Spherical Whittaker functions on the metaplectic n-fold cover of GL(r+1) over
a nonarchimedean local field containing n distinct n-th roots of unity may be
expressed as the partition functions of statistical mechanical systems that are
variants of the six-vertex model. If n=1 then in view of the Casselman-Shalika
formula this fact is related to Tokuyama's deformation of the Weyl character
formula. It is shown that various properties of these Whittaker functions may
be expressed in terms of the commutativity of row transfer matrices for the
system. Potentially these properties (which are already proved by other
methods, but very nontrivial) are amenable to proof by the Yang-Baxter
equation
Remote Hand Pump Monitoring in Africa
Millions of communities in developing countries rely on hand pumps installed by various non-governmental organizations (NGOs). Studies have shown that these pumps are often broken with significant delays before maintenance people arrive. During the last few years, the Intelligent Water Project (IWP), in cooperation with World Vision and AlignedWorks has successfully produced sensor units, installed on each water pump to provide state of operation information, which proves the feasibility of remote monitoring through a real-time web-based database. Currently, we are working to demonstrate reliability, improve accuracy, and prepare for production on a larger scale to expand the impact to more communities all over Africa. Recently we have been moving toward this goal by producing all necessary documentation to manufacture our system and prove its functionality with quality control procedures. This involves creating drawings of each component and assembly and using these along with complete manufacturing, quality control check, and installation instructions.https://mosaic.messiah.edu/engr2020/1009/thumbnail.jp
Application of advanced technologies to small, short-haul aircraft
The results of a preliminary design study which investigates the use of selected advanced technologies to achieve low cost design for small (50-passenger), short haul (50 to 1000 mile) transports are reported. The largest single item in the cost of manufacturing an airplane of this type is labor. A careful examination of advanced technology to airframe structure was performed since one of the most labor-intensive parts of the airplane is structures. Also, preliminary investigation of advanced aerodynamics flight controls, ride control and gust load alleviation systems, aircraft systems and turbo-prop propulsion systems was performed. The most beneficial advanced technology examined was bonded aluminum primary structure. The use of this structure in large wing panels and body sections resulted in a greatly reduced number of parts and fasteners and therefore, labor hours. The resultant cost of assembled airplane structure was reduced by 40% and the total airplane manufacturing cost by 16% - a major cost reduction. With further development, test verification and optimization appreciable weight saving is also achievable. Other advanced technology items which showed significant gains are as follows: (1) advanced turboprop-reduced block fuel by 15.30% depending on range; (2) configuration revisions (vee-tail)-empennage cost reduction of 25%; (3) leading-edge flap addition-weight reduction of 2500 pounds
Ethnopolitics Across Central and Eastern Europe in a State of Flux: Time for Updating and Upgrading?
This chapter illustrates why and how the existing theoretical models in the study of ethnopolitics need to be updated in light of the latest developments and the increasing impact of new catalysts. These are, namely, anti-immigration and the rise of the populist and radical right across Central and Eastern Europe. This chapter hints that the more systematic cooperation between academic experts in nationalism and academic experts in the populist and radical right will enable: (a) the former to assess more accurately the degree to which new variables such as Euroscepticism and anti-immigrant trends can reshape ethnopolitics, both as a living reality and a field of study, across Central and Eastern Europe; (b) the latter to formulate new interpretative models about how (right-wing) populist and Eurosceptic actors embed their agendas inside the pre-existing political cultures of nationalism and particularistic identity and memory politics. This chapter introduces and outlines the ethnosymbolic approach as well as the triadic and quadratic configurations of ethnopolitics. Then, it proceeds into a more empirical assessment of the applicability of these theoretical approaches in a series of case studies during the 1990s, as well as the more recent emergence of new catalysts and the ensuing necessity to update and upgrade the existing theoretical models
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