1,213 research outputs found
Species composition, distribution, and relative abundance of fishes in the coastal habitat off the southeastern United States
Ichthyofauna of the coastal «10 m depth) habitat of the South Atlantic Bight were investigated between Cape Fear, North Carolina, and the St. John's River, Florida. Trawl collections from four nonconsecutive seasons in the period July 1980 to December 1982 indicated that the fish community is dominated by the family Sciaenidae, particularly juvenile forms. Spot (Leiostomus xanthurus) and Atlantic croaker (Micropogonias undulatus) were the two most abundant species and dominated catches during all seasons. Atlantic menhaden (Brevoortin tyrannus) was also very abundant, but only seasonally (winter and spring) dominant in the catches. Elasmobranch fIShes, especially
rajiforms and carcharinids, contributed to much of the biomass of fishes collected. Total fish abundance was greatest in winter and lowest in summer and was influenced by the seasonality of Atlantic menhaden and Atlantic croaker in the catches. Biomass was highest in spring and lowest in summer, and was influenced by biomass of spot. Fish density ranged from 321 individuals and 12.2 kg per hectare to 746 individuals and 25.2 kg per hectare. Most species ranged widely throughout the bight, and showed some evidence of seasonal migration. Species assemblages were dominated by ubiquitous year-round residents of the coastal waters of the bight. Diversity (H') was highest in summer, and appeared influenced by the evenness of distribution
of individuals among species. (PDF file contains 56 pages.
Media Literacy Definitions
This thesis conducts a critical discourse analysis on definitions of the term “media literacy” used by researchers in media literacy educational interventions. These definitions are compared to the skills developed in participants of media literacy interventions. This comparison reveals if and how researchers are operationalizing their stated definition of media literacy. Over half of researchers are using the definition proffered by the National Association for Media Literacy Education. However the disagreement in the field around a definition of the term “media literacy” has created confusion. This confusion has left educators falling back on practices scaffolded by the previous educational paradigm. This research finds that the definition of media literacy put forth by NAMLE addresses the paradigm shift that has taken place in the field
A study of the archibenthic and abysobenthic fishes of Deep Water Dump Site 106 and the adjacent area : completion report
Deep water dtnnp site 106 (DWD 106) is located 145 km off the coast of New Jersey and is bounded by the latitudes of ! 38°40\u27 and 39°00\u27N and longitudes 72°00\u27 and 72°30\u27W. The depth of DWD 106 varies from about 1300 min the northeast corner to • 2700 min the southwest (Fig. 1). Most of the site is deeper than 2000 m. Within DWD 106 is a smaller dwnp site that has been in use for many years for industrial wastes and munitions. Due south of DWD 106 is an additional dwnpsite (Fig. 1) at which the Atomic Energy Commission reported dumping radioactive wastes (rad site). The purpose of this report is to describe the fish fauna in the area of DWD 106 and to provide information on the ecology of dominant species
Compressed sensing quantum process tomography for superconducting quantum gates
We apply the method of compressed sensing (CS) quantum process tomography
(QPT) to characterize quantum gates based on superconducting Xmon and phase
qubits. Using experimental data for a two-qubit controlled-Z gate, we obtain an
estimate for the process matrix with reasonably high fidelity compared
to full QPT, but using a significantly reduced set of initial states and
measurement configurations. We show that the CS method still works when the
amount of used data is so small that the standard QPT would have an
underdetermined system of equations. We also apply the CS method to the
analysis of the three-qubit Toffoli gate with numerically added noise, and
similarly show that the method works well for a substantially reduced set of
data. For the CS calculations we use two different bases in which the process
matrix is approximately sparse, and show that the resulting estimates of
the process matrices match each ther with reasonably high fidelity. For both
two-qubit and three-qubit gates, we characterize the quantum process by not
only its process matrix and fidelity, but also by the corresponding standard
deviation, defined via variation of the state fidelity for different initial
states.Comment: 16 pages, 11 figure
On the NP-Hardness of Approximating Ordering Constraint Satisfaction Problems
We show improved NP-hardness of approximating Ordering Constraint
Satisfaction Problems (OCSPs). For the two most well-studied OCSPs, Maximum
Acyclic Subgraph and Maximum Betweenness, we prove inapproximability of
and .
An OCSP is said to be approximation resistant if it is hard to approximate
better than taking a uniformly random ordering. We prove that the Maximum
Non-Betweenness Problem is approximation resistant and that there are width-
approximation-resistant OCSPs accepting only a fraction of
assignments. These results provide the first examples of
approximation-resistant OCSPs subject only to P \NP
A temporal and spatial study of invertebrate communities associated with hard-bottom habitats in the South Atlantic Bight
Species composition, biomass, density, and diversity of benthic invertebrates from six bard-bottom areas were evaluated. Seasonal collections using a dredge, trawl, and suction and grab samplers yielded 432, 525, and 845 taxa, respectively. Based on collections wltb the different gear types, species composition of invertebrates was found to change bathymetrically. Inner- and mlddle-shelf sites were more similar to each other in terms of invertebrate species composition than they were to outer-shelf sites, regardless of season. Sites on the inner and outer shelf were grouped according to latitude; however, results suggest that depth is apparently a more important determinant of invertebrate species composition than either season or latitude. Sponges generally dominated dredge and trawl collections in terms of biomass. Generally, cnidarians, bryozoans, and sponges
dominated at sites In terms of number of taxa collected.
The most abundant smaller macrofauna collected in suction and grab samples were polychaetes, amphipods, and mollusks. Densities of the numerically dominant species changed botb seasonally and bathymetrically, with very few of these species restricted to a specific bathymetrlc zone.
The high diversity of invertebrates from hard-bottom sites is attributed to the large number of rare species. No consistent seasonal changes in diversity or number of species were noted for individual stations or depth zones. In addition, H and its components showed no definite patterns related to depth or latitude. However, more species were collected at middle-shelf sites than at inner- or outer-shelf sites, which may be related to more
stable bottom temperature or greater habitat complexity in that area. (PDF file contains 110 pages.
CARET analysis of multithreaded programs
Dynamic Pushdown Networks (DPNs) are a natural model for multithreaded
programs with (recursive) procedure calls and thread creation. On the other
hand, CARET is a temporal logic that allows to write linear temporal formulas
while taking into account the matching between calls and returns. We consider
in this paper the model-checking problem of DPNs against CARET formulas. We
show that this problem can be effectively solved by a reduction to the
emptiness problem of B\"uchi Dynamic Pushdown Systems. We then show that CARET
model checking is also decidable for DPNs communicating with locks. Our results
can, in particular, be used for the detection of concurrent malware.Comment: Pre-proceedings paper presented at the 27th International Symposium
on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur,
Belgium, 10-12 October 2017 (arXiv:1708.07854
Improving the Coherence Time of Superconducting Coplanar Resonators
The quality factor and energy decay time of superconducting resonators have
been measured as a function of material, geometry, and magnetic field. Once the
dissipation of trapped magnetic vortices is minimized, we identify surface
two-level states (TLS) as an important decay mechanism. A wide gap between the
center conductor and the ground plane, as well as use of the superconductor Re
instead of Al, are shown to decrease loss. We also demonstrate that classical
measurements of resonator quality factor at low excitation power are consistent
with single-photon decay time measured using qubit-resonator swap experiments.Comment: 3 pages, 4 figures for the main paper; total 5 pages, 6 figures
including supplementary material. Submitted to Applied Physics Letter
Denaturation transition of stretched DNA
We generalize the Poland-Scheraga model to consider DNA denaturation in the
presence of an external stretching force. We demonstrate the existence of a
force-induced DNA denaturation transition and obtain the temperature-force
phase diagram. The transition is determined by the loop exponent for which
we find the new value such that the transition is second order
with in . We show that a finite stretching force
destabilizes DNA, corresponding to a lower melting temperature , in
agreement with single-molecule DNA stretching experiments.Comment: 5 pages, 3 figure
Calcium-ion transport by intact Ehrlich ascites-tumour cells. Role of respiratory substrates, Pi and temperature
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