361 research outputs found
A Computational Introduction to Elliptic and Hyperelliptic Curve Cryptography
At its core, cryptography relies on problems that are simple to construct but difficult to solve unless certain information (the “key”) is known. Many of these problems come from number theory and group theory. One method of obtaining groups from which to build cryptosystems is to define algebraic curves over finite fields and then derive a group structure from the set of points on those curves. This thesis serves as an exposition of Elliptic Curve Cryptography (ECC), preceded by a discussion of some basic cryptographic concepts and followed by a glance into one generalization of ECC: cryptosystems based on hyperelliptic curves
Assessing multiple threats to seabird populations using flesh-footed shearwaters Ardenna carneipes on Lord Howe Island, Australia as case study
Phenyl replacement reactions: solvent effects on reactions of boroxines with primary amines
When primary amines are reacted with boroxines in solvents such as diethyl ether or THF, a dative bond forms between the lone pair of electrons on the nitrogen atom and a boron atom in a predictable manner. However, when the highly complexing solvent dioxane is used, evidence of a phenyl displacement reaction has been observed. In this work I examined the effects of a variety of electron donating and withdrawing groups on boroxines, specifically whether or not these groups have an effect on the proposed outcome of the hypothesized phenyl displacement reaction. The types of boroxines and amines were varied as well as their relative ratios. The resulting reaction mixtures were evaluated by 1H-NMR, GC-MS and FT-IR. The nitrogen boron dative bond complex formed rather than the desired phenyl replacement product
Renal and hemodynamic responses to bumetanide in hypertension: Effects of nitrendipine
Renal and hemodynamic responses to bumetanide in hypertension: Effects of nitrendipine. The effects of a calcium antagonist on the response to a loop diuretic were tested in eight hypertensive patients while they received 120mmol · 24hr-1 of dietary Na. Nitrendipine (N; 20 mg) or placebo (P) was administered twice daily for five days and bumetanide (B; 1 mg, i.v.) for the last three days of each period. Cardiac index (CI) was measured during tilt. B alone significantly (P < 0.05; N = 7) reduced CI and increased total peripheral resistance; N prevented these effects of B. Neither drug altered BP consistently. Although three days of B increased plasma renin activity (PRA) during P and N, it increased plasma aldosterone (PAldo) only during P (P, 4.4 ± 1.3 to 7.6 ± 1.0; P < 0.05. N, 5.7 ± 1.3 to 6.0 ± 1.3; pg · liter-1; NS). B increased Na excretion without changing GFR or RPF; this was followed by 18 hours of decreased renal Na excretion. These actions were unchanged by N. N did not change the cumulative excretion of B (P, 268 ± 35 vs. N, 217 ± 21 µg) or the relationship between Na excretion and the log of B excretion. However, Na excretion was increased (P < 0.05) by 40 to 60% in the six hour period following the first two doses of N. Therefore, the cumulative Na balance was more negative during five days of N (P, -47 ± 17 vs. N, -108 ± 24 mmol; P < 0.05). The effect of N and B on Na balance were independent. In conclusion, short-term administration of N: 1) increases CI and reduces TPRI in the post-diuretic state; 2) blunts B-induced increase in PAldo without modifying the rise in PRA; 3) does not change B kinetics or dynamics or the post-diuretic period of renal Na retention; 4) causes negative Na balance which is additive with that produced by B
Davis Creek Dredge Channel Data Report
Introduction Davis Creek is located in Mathews County, Virginia (Figure 1) and empties into Mobjack Bay, a small bay in the lower Chesapeake Bay. The creek has a narrow mouth that splits into three prongs (Figure 2). The eastern prong is shortest at 2,200 ft from the mouth, and the western prong is the longest extending about 3,000 ft from the mouth. The Marina on Davis Creek occurs on this prong. Land use adjacent to the creek is mostly residential with some agriculture and wooded properties. The headwaters do not have extensive marsh. Instead the creek terminates soon after the channel narrows at the headwaters. Davis Creek has historically been the location of an active working waterfront. (...
Lake-level Variability and Water Availability in the Great Lakes
Key components of water availability in a hydrologic system4 are the amount of water in storage and the variability of that amount. In the Great Lakes Basin, a vast amount of water is stored in the lakes themselves. Because of the lakes’ size, small changes in water levels cause huge changes in the amount of water in storage. Approximately 5,439 mi3 of water, measured at chart datum, is stored in the Great Lakes. A change of 1 ft in water level over the total Great Lakes surface area of 94,250 mi2 means a change of 18 mi3 of water in storage. Changes in lake level over time also play an important role in human activities and in coastal processes and nearshore ecosystems, including development and maintenance of beaches, dunes, and wetlands.
The purpose of this report is to present recorded and reconstructed (pre-historical) changes in water levels in the Great Lakes, relate them to climate changes of the past, and highlight major water-availability implications for storage, coastal ecosystems, and human activities. Reconstructed water-level changes have not been completed for all Great Lakes; consequently, this report presents these changes primarily for Lakes Michigan and Huron, with some reference to Lake Superior also
Aberdeen Creek Dredge Channel Data Report
Aberdeen Creek is located on the York River in Gloucester County, Virginia (Figure 1). At the narrow confluence of the York and Aberdeen, the creek takes about a 90-degree bend to the north (Figure 2) and widens to about 700 to 800 feet (ft) for about 2,000 ft. The creek then divides into two branches, one continuing north and one going east. These two prongs narrow quickly and become thin meandering tidal channels with adjacent marsh. The land use around the creek is mostly agricultural and wooded with some residential properties along its east side and along the York River shoreline. The west side of the creek is defined by a sand spit vegetated with high and low marsh that widens quickly into a peninsula north of the entrance. This spit has formed over the years of southward transport of eroding bank sediment along the York River. A sandy spit also occurs on the south side of the channel and has moved across a small tidal channel/marsh coming into Aberdeen Creek from the southeast. (...
From aptamer-based biomarker discovery to diagnostic and clinical applications: an aptamer-based, streamlined multiplex proteomic assay
Recently, we reported an aptamer-based, highly multiplexed assay for the purpose of biomarker identification. To enable seamless transition from highly multiplexed biomarker discovery assays to a format suitable and convenient for diagnostic and life-science applications, we developed a streamlined, plate-based version of the assay. The plate-based version of the assay is robust, sensitive (sub-picomolar), rapid, can be highly multiplexed (upwards of 60 analytes), and fully automated. We demonstrate that quantification by microarray-based hybridization, Luminex bead-based methods, and qPCR are each compatible with our platform, further expanding the breadth of proteomic applications for a wide user community
Hog Island Shore Protection and Habitat Restoration Living Shoreline Project
Hog Island is an emergent estuarine marsh complex that is part of the overall Guinea marshes (Figure 1). These marshes are located at the confluence of Mobjack Bay and the York River in Gloucester County, Virginia. Hog Island is a high wave energy eroding shoreline along its south-face on the York River, and lower wave energy along its west and east flanks that occur on Monday Creek (Figure 2). The marsh consists mainly of grasses such as Spartina alterniflora and Spartina patens. A higher, sandy area along the higher energy shorelines has some scrub shrub. Two small ponds and a small creek occur on the interior of the marsh. The edge of the island is irregularly shaped with exposed peat and peat scarps along the shoreline (Figure 3).
Hog Island is critical for several reasons including: (1) Guinea Marsh Islands are important maritime habitats for shorebirds, waterfowl, as well as many important marine species; (2) Guinea Marsh Islands provide a storm surge break to the marsh complex inside Monday Creek and down the Mobjack Bay side towards the Severn, which will soon be marshes owned by the Virginia Department of Wildlife Resources; (3) Monday Creek has two aquaculture operations inside of the creek and the uplands provide a storm break for growing oysters; and (4) There are many FEMA repetitive loss structures in Guinea. Protecting these islands reduces the amount of storm surge energy entering the creek and thus reduces flood damage. As such, this project took conservation, resiliency, and protection aspects into consideration when assessing Hog Island for shore protection and habitat restoration. To determine management strategy suitability, the site assessment included hydrodynamic, physical, and biotic conditions existing at the site
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