27,290 research outputs found
Legitimizing Elections Through the Regulation of Campaign Financing: A Comparative Constitutional Analysis and Hope for South Africa
Actual or apparent corruption can seriously undermine any democratic system. This Article examines two approaches to tackling this problem in South Africa. The libertarian approach, used in the United States, embodies a strong presumption against regulation of campaign financing on the basis that it is a violation of the constitutional rights to free speech and association. The weak regulations that result from this system do little to stem the influence of a powerful few on the outcomes of national elections. A better approach for South Africa is the egalitarian model, used in both the United Kingdom and Canada. This model focuses on leveling the playing field for participants. Under this model, rights are subject to greater regulation so long as the government can provide sufficient justification. South Africa’s current system, by requiring proportional national funding of political parties, but leaving private financing largely unregulated, has resulted in a virtual one-party state in which private funding dominates. To solve these problems, South Africa should embrace the egalitarian model by implementing spending caps and increasing transparency
Monitoring Real-time Metabolite Trafficking in the Brain using Microelectrochemical Biosensors
In a first series of experiments a glucose oxidase-based
biosensor implanted in the striatum of freely moving rats
was used to determine the concentration of brain
extracellular (ECF) glucose in two distinct ways. With a
modification of the zero-net-flux method, in which
different concentrations of glucose are infused through a
dialysis probe glued to the biosensor, the concentration at
which there was no change in glucose current was
calculated by regression analysis; this gave an ECF
concentration of 351 ± 16 μM. The concentration
calculated from the basal current and the
in vitro
calibration of the biosensor was not significantly different
from this. The basal extracellular glucose concentration
determined by either method remained constant over a
period of several days. In a
second series of experiments
rats were implanted in the striatum with a Pt/Ir electrode
for measurement of regional cerebral blood flow (rCBF,
H
2
clearance technique), a carbon paste electrode for
monitoring tissue oxygen, and a glucose biosensor for
monitoring extracellular glucose. There was a parallel
increase in rCBF and oxygen in response to neuronal
activation (5 min tail pinch). During the neuronal
activation there was a decrease in ECF glucose which was
followed by a slow rise that took 30 min to return to basal
levels. Finally, a group of rats implanted with a combined
glucose biosensor and dialysis probe were given a 5 min
tail pinch while the dialysis probe was perfused with
either artificial cerebrospinal
fluid (aCSF) alone or aCSF
with the addition of the
β
-adrenoceptor antagonist
propranolol. Perfusion with aCSF once again produced an
initial reduction in extracellular glucose, which was co-
extensive with the period of stimulation, followed by a
delayed and long-lasting increase in glucose. Propranolol
had no effect on basal levels
of glucose but suppressed the
delayed increase. These results suggests that
extracellular
glucose in the brain is not derived directly from the blood
vascular system but from some other source which is
most likely to be astrocyte
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In Defense of Natural Cement: A Critical Examination of the Evolution of Concrete Technology at Fort Totten, New York
There are a number of opportunities for academic research related to the historic concrete fortifications at Fort Totten at Willets Point in Queens, NY. Built by U.S. Army Corps of Engineers (USACE), whose headquarters was at Willets Point, these structures incorporate three significant fortification periods, including the Third System (1863-1867), the Post-Civil War era (1867-1884) and the Endicott period (1891-1905). These late 19th century structures represent a transformative period in the technological development of concrete which evolved from a simple mortar containing rocks to bulk out the mix, to an interdependent mixture of binder, sand and aggregate. In addition, the first fortifications at Fort Totten were built during the heyday of the natural cement industry and the last fortifications coincided with its demise, as portland cement came to dominate the market. The rivalry between American natural and portland cement manufacturers was fierce, and the biases engendered on both sides persisted long after the natural cement industry collapsed in the early 20th century. This has translated into the conventional view that there was an inherent problem in the natural cement concrete used to build these fortifications. However, for reasons of economy, the Corps of Engineers were prevented from using portland cement, until advances in domestic manufacturing permitted a reduction in costs. Through historical and archival research, as well as the petrographic analysis of concrete samples, a more detailed assessment of the concrete used at Fort Totten was conducted. Using polarized light microscopy an analysis was conducted on the binder, the aggregates, the gradation, the water/cement ratio, and any deterioration in order to evaluate changes in the concrete mix design over time. These observations were then related to a conditions survey of the concrete structures at Fort Totten, to assess the performance of the concrete used to build these historic structures. Laboratory work for this thesis was conducted at Columbia University GSAPP’s Historic Preservation Conservation Laboratory and at Highbridge Materials Consulting, Inc
A new approach to data publication in ocean sciences
Data are collected from ocean sciences activities that range from a single investigator working in a laboratory to large teams of scientists cooperating on big, multinational, global ocean research projects. What these activities have in common is that all result in data, some of which are used as the basis for publications in peer-reviewed journals.However, two major problems regarding data remain. First, many data valuable for understanding ocean physics, chemistry, geology, biology, and how the oceans operate in the Earth system are never archived or made accessible to other scientists. Data underlying traditional journal articles are often difficult to obtain. Second, when scientists do contribute data to databases, their data become freely available, with little acknowledgment and no contribution to their career advancement. To address these problems, stronger ties must be made between data repositories and academic journals, and a “digital backbone” needs to be created for data related to journal publications
An evolution strategy to estimate emission source distributions on a regional scale from atmospheric observations
International audienceIn this paper we present an Evolution Strategy (ES) approach towards the estimation of the location and strength of surface emissions of trace gases based on atmospheric concentration measurements and back-trajectory analyses. The details of the ES developed are outlined. The ES is tested using artificial emission maps at different grid resolutions and the results compared to those obtained on the same problems using Singular Value Decomposition (SVD). In almost all cases, the ES improves on SVD at equivalent resolutions. In addition, a number of insights, which the ES approach brings to the problem of source location and emission strength, are discussed, particularly the limitations on the use of measurement and meteorological data in the determination of emission source distribution
Rotation and Color Properties of the Nucleus of Comet 2P/Encke
We present results from CCD observations of comet 2P/Encke acquired at
Steward Observatory's 2.3m Bok Telescope on Kitt Peak obtained in Oct. 2002,
when the comet was near aphelion. Rotational lightcurves in B, V and R-filters
were acquired over two nights of observations, and analysed to study the
physical and color properties of the nucleus. The average apparent R-filter
magnitude across both nights corresponds to a mean effective radius of 3.95 +/-
0.06 km. The rotational lightcurve results in a nucleus axial ratio a/b >= 1.44
+/- 0.06 and semi-axes lengths of [3.60 +/- 0.09] x [5.20 +/- 0.13] km. Our
data includes the first detailed time series multi-color measurements of a
cometary nucleus, and significant color variations were seen. The average color
indices across both nights are: (V-R) = 0.39 +/- 0.06 and (B-V) = 0.73 +/- 0.06
(R_mean = 19.76 +/- 0.03). We linked our data with the September 2002 data from
Fernandez et al. (2005) - taken just 2-3 weeks before the current data set -
and we show that a rotation period of 11.083 +/- 0.003hours works extrememly
well for the combined data set.Comment: Accepted for publication in Icarus (Dec 2006). 27 page
Microelectrochemical Sensors for In Vivo Brain Analysis: An Investigation of Procedures for Modifying Pt Electrodes Using Nafion®
Various Nafion® coating procedures were examined in order to design a simple and reproducible coating method to maximise permselective characteristics, and thus eliminate signals from electroactive interferents, in sensors designed for direct in vivo measurements in the brain. Interferents investigated included ascorbic acid (AA), the principal endogenous electroactive interferent present in the brain, and uric acid. Application of the Nafion® (5% commercial solution) using a thermally annealing procedure involving 5 pre-coats, and 2 subsequent dip-bake layers resulted in elimination of interferent signals. It also produced complete blocking of the signal for the neurotransmitter dopamine. The optimum time and temperature for annealing was found to be 5 min at 210 °C. An examination of shelf life over two weeks indicated negligible AA interference over this period. Preliminary investigations with respect to the potential use of these Nafion®-modified Pt electrodes in the design of implantable, first generation, peroxide detecting biosensors indicated that the modified electrode had no effect on O2 permeability but did produce a significant decrease in H2O2 sensitivity. While this may preclude their use in biosensor development they may be more suitable for detection of gaseous neurochemicals such as nitric oxide
Incidence, correlates, and origins of dioecy in the Island Flora of New Caledonia
Premise of research. Because it is an inherently risky sexual system, dioecy is globally rare. Attempts to explain unusually high incidences of dioecy on certain islands have generated a considerable literature on the relationships among dioecy, its ecological correlates, establishment after transoceanic dispersal, and postdispersal speciation. Nevertheless, few studies of dioecy on islands have included considerations of the origins and maintenance of dioecy on islands along with determinations of its incidence. Methodology. We used the literature, herbarium specimens, and fieldwork to determine the incidence of dioecy in the native angiosperm flora of New Caledonia. We inferred the number and characteristics of colonists needed to account for the extant dioecious flora. We made traditional species-based numerical assessments of associations between dioecy on New Caledonia and woodiness, plain flowers, fleshy fruit, habitat, and endemism, and we constructed a phylogenetic tree for New Caledonia's native angiosperms to investigate correlated evolution of dioecy and those associated traits. Pivotal results. This study is the first comprehensive survey of sexual systems for the flora of New Caledonia. One-fifth of New Caledonia's native angiosperms are dioecious. Dioecy is numerically overrepresented among species that are woody, have plain flowers, have fleshy fruit, occur in rainforest, or are endemic. However, we found strong evidence for correlated evolution only for dioecy and woodiness, plain flowers, and fleshy fruit. Dioecious groups with more of the widely accepted morphological correlates of dioecy tend to be more speciose. Approximately 90% of the colonists that gave rise to the extant dioecious flora were themselves dioecious. Approximately 60% of the colonists have two or more dioecious descendants, and those descendants comprise more than 90% of the extant dioecious species. Conclusions. Successful dispersal and establishment of already dioecious colonists and autochthonous speciation of dioecious lineages are primarily responsible for the high incidence of dioecy on New Caledonia. There were relatively few postdispersal transitions to dioecy. The associations of dioecy with woodiness, plain flowers, and fleshy fruit result from correlated evolution that occurred prior to dispersal to New Caledonia, while the associations of dioecy with rainforest habitat and endemism appear to result from autochthonous speciation of dioecious lineages. With similar to similar to 4% of the world's dioecious species occurring only there, New Caledonia should be a rich source of new information on the evolutionary ecology of dioecy. Realization of this potential will require both further study and concerted efforts to preserve the native flora
Mosquitoes of New Hampshire, Bulletin, no. 243
The Bulletin is a publication of the New Hampshire Agricultural Experiment Station, College of Life Sciences and Agriculture, University of New Hampshire, Durham, New Hampshire
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