1,579 research outputs found
Observations of the Vertical Structure of Tidal Currents in Two Inlets
Observations of the vertical structure of broad band tidal currents were obtained at two energetic inlets. Each experiment took place over a 4 week period, the first at Hampton Inlet in southeastern New Hampshire, USA, in the Fall of 2011, and the second at New River Inlet in southern North Carolina, USA, in the spring of 2012. The temporal variation and vertical structure of the currents were observed at each site with 600 kHz and 1200 kHz RDI Acoustic Doppler Current Profilers (ADCP) deployed on low-profile bottom tripods in 7.5 and 12.5 m water depths near the entrance to Hampton Inlet, and in 8 and 9 m water depth within and outside New River Inlet, respectively. In addition, a Nortek Aquapro ADCP was mounted on a jetted pipe in about 2.5 m water depth on the flank of the each inlet channel. Flows within the Hampton/Seabrook Inlet were dominated by semi-diurnal tides ranging 2.5 - 4 m in elevation, with velocities exceeding 2.5 m/s. Flows within New River inlet were also semi-diurnal with tides ranging about 1 – 1.5 m in elevation and with velocities exceeding 1.5 m/s. Vertical variation in the flow structure at the dominant tidal frequency are examined as a function of location within and near the inlet. Outside the inlet, velocities vary strongly over the vertical, with a nearly linear decay from the surface to near the bottom. The coherence between the upper most velocity bin and the successively vertically separated bins drops off quickly with depth, with as much as 50% coherence decay over the water column. The phase relative to the uppermost velocity bin shifts over depth, with as much as 40 deg phase lag over the vertical, with bottom velocities leading the surface. Offshore, rotary coefficients indicate a stable ellipse orientation with rotational directions consistent over the vertical. At Hampton, the shallower ADCP, but still outside the inlet, shows a rotational structure that changes sign in the vertical indicating a sense of rotation at the bottom that is opposite to that at the surface. Within the inlet, the flow is more aligned with the channel, the decay in amplitude over the vertical is diminished, the coherence and phase structure is nearly uniform, and the rotary coefficients indicate no sense of rotation in the flow. The observations are qualitatively consistent with behavior described by Prandle (1982) for shallow water tidal flows
Deployment of a bottom monitor at a 30 meters deep site in the New York Bight Apex during the summer of 1993
A bottom instrument was deployed on May 5,1993, recovered and redeployed on June 22, 1993 and finally recovered on July
28, 1993 at a 30 meter site in the New York Bight Apex. The instrument measured currents, suspended sediment concentrations,
pressure, temperature and conductivity. The data storage was filled in only seven days on the first deployment as in 18 days in the
second. The averaging sampling process worked well, producing hourly (first deployment) and half hourly (second deployment)
values of all sensors and instrument internal diagnostics to obtain background environmental information. The burst sampling
scheme sampled once a day for waves, and identified 6 and 10 second waves present. The event sampling scheme was tested for the
first time. During deployment one, high frequency pressure signals were allowed to trigger events, and bad cabling caused
excessive events to be recorded, filling the memory prematurely. For deployment two, only the optical sediment sensors were
allowed to trigger events, and 146 events were recorded. Many of the events were only seen in one or the other optical sensor and
probably associated with fish or floating debris. Other events had unique signatures, one type possibly due to passing ships.Funding was provided by the National Oceanic and Atmospheric Administration and the U.S.
Army Corps of Engineers, New York District
CULTURE, MEDIA AND POWER: UNDERSTANDING COMMUNITY SERVICE THROUGH MEDIA REPRESENTATION
The study aims to examine the culture and ideological underpinnings espoused by Newsette, the official publication of De La Salle University-Dasmariñas (DLSU-D), through examination of headlines of articles pertaining to the promotion of culture of community extension service of DLSU-D. Specifically, it aims to: (1) define the ideology espoused on community service; (2) determine the linguistic concepts; (3) and examine the manipulation techniques used by the publication to its readers. Data were obtained through discourse analysis of the publication’s headlines. Analysis of this study allows an understanding of the standpoint of Newsette on community development endeavors of the University. It identifies salient points in illuminating messages which are revealing of the social and cultural representations on community services in the University. More importantly, the results provide building material for opinion and explanation of the impression, acceptance and participation of Lasallians towards community extension services
Polaritonic characteristics of insulator and superfluid phases in a coupled-cavity array
Recent studies of quantum phase transitions in coupled atom-cavity arrays
have focused on the similarities between such systems and the Bose-Hubbard
model. However, the bipartite nature of the atom-cavity systems that make up
the array introduces some differences. In order to examine the unique features
of the coupled-cavity system, the behavior of a simple two-site model is
studied over a wide range of parameters. Four regions are identified, in which
the ground state of the system may be classified as either a polaritonic
insulator, a photonic superfluid, an atomic insulator, or a polaritonic
superfluid.Comment: 7 pages, 9 figures, 1 table, REVTeX 4; published versio
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Evaluating candidate reactions to selection practices using organisational justice theory
Objectives: This study aimed to examine candidate reactions to selection practices in postgraduate medical training using organisational justice theory.
Methods: We carried out three independent cross-sectional studies using samples from three consecutive annual recruitment rounds. Data were gathered from candidates applying for entry into UK general practice (GP) training during 2007, 2008 and 2009. Participants completed an evaluation questionnaire immediately after the short-listing stage and after the selection centre (interview) stage. Participants were doctors applying for GP training in the UK. Main outcome measures were participants’ evaluations of the selection methods and perceptions of the overall fairness of each selection stage (short-listing and selection centre).
Results: A total of 23 855 evaluation questionnaires were completed (6893 in 2007, 10 497 in 2008 and 6465 in 2009). Absolute levels of perceptions of fairness of all the selection methods at both the short-listing and selection centre stages were consistently high over the 3 years. Similarly, all selection methods were considered to be job-related by candidates. However, in general, candidates considered the selection centre stage to be significantly fairer than the short-listing stage. Of all the selection methods, the simulated patient consultation completed at the selection centre stage was rated as the most job-relevant.
Conclusions: This is the first study to use a model of organisational justice theory to evaluate candidate reactions during selection into postgraduate specialty training. The high-fidelity selection methods are consistently viewed as more job-relevant and fairer by candidates. This has important implications for the design of recruitment systems for all specialties and, potentially, for medical school admissions. Using this approach, recruiters can systematically compare perceptions of the fairness and job relevance of various selection methods
Dynamics in a coupled-cavity array
The dynamics of a system composed of two coupled optical cavities, each
containing a single two-level atom, is studied over a wide range of detuning
and coupling values. A description of the field in terms of delocalized modes
reveals that the detuning between the atoms and these modes is controlled by
the coupling between the cavities; this detuning in turn governs the nature of
the dynamics. If the atoms are highly detuned from both delocalized field
modes, the dynamics becomes dispersive and an excitation may be transferred
from the first atom to the second without populating the field. In the case of
resonance between the atoms and one of the delocalized modes, state transfer
between the atoms requires intermediate excitation of the field. Thus the
interaction between the two atoms can be controlled by adjusting the coupling
between the cavities.Comment: 11 pages, 3 figure
The annual variation of water mass structure in the Gulf of Maine: 1986-1987
The annual variation in the structure and disposition of the principal water masses in the Gulf of Maine has been investigated with a set of water property observations using five shipboard surveys and four moored arrays with data telemetry. The time series observations document the cooling-induced destratification of the upper water column during autumn and the subsequent mixed-layer deepening in the western Gulf—primarily in Wilkinson Basin— during winter 1987. Unusually large amounts of fresher Scotian Shelf Water inflow inhibited winter 1987 vertical mixing in the eastern Gulf relative to the deep mixing in and around Wilkinson Basin in the western Gulf. The net result of these processes was a 1987 Gulf that was colder and fresher than the 1986 Gulf. Detailed histories of the thicknesses of the principal water masses in the Gulf—namely, Maine Surface Water, Maine Intermediate Water, and Maine Bottom Water—at the mooring sites reveal the early summer progression of Slope and Bottom Water from the Northeast Channel to Georges Basin and on to Jordan Basin. Maine Intermediate Water made up nearly 50% of the entire volume of the Gulf in early spring 1987. During the summer, Maine Intermediate Water in the eastern Gulf was replaced by a warmer water mass we call Summer Intermediate Water. A spring-summer 1987 sequence of CTD-derived water mass distribution maps documents (1) the retreat of Maine Intermediate Water into Wilkinson Basin, (2) the westward spread of Summer Intermediate Water, and (3) the inflow of Slope Water. A simple water mass conservation model indicates that 72% of the Maine Intermediate Water loss flows out of the observation domain at a rate of 0.21 × 106 m3/s, while the other 28% contributes, through mixing with Surface Water and Bottom Water in the eastern Gulf, to the production of Summer Intermediate Water. The combined inflow of Slope Water (0.11 × 106 m3/s), Bottom Water (0.03 × 106 m3/s), and Summer Intermediate Water (0.07 × 106 m3/s) appears to have balanced the April-July outflow of Maine Intermediate Water
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