174 research outputs found
Land-Use and Land-Cover Change around Mobile Bay, Alabama from 1974-2008
This document summarizes the major findings of a Gulf of Mexico Application Pilot project led by NASA Stennis Space Center (SSC) in conjunction with a regional collaboration network of the Gulf of Mexico Alliance (GOMA). NASA researchers processed and analyzed multi-temporal Landsat data to assess land-use and land-cover (LULC) changes in the coastal counties of Mobile and Baldwin, AL between 1974 and 2008. Our goal was to create satellite-based LULC data products using methods that could be transferable to other coastal areas of concern within the Gulf of Mexico. The Mobile Bay National Estuary Program (MBNEP) is the primary end-user, however, several other state and local groups may benefit from the project s data products that will be available through NOAA-NCDDC s Regional Ecosystem Data Management program. Mobile Bay is a critical ecologic and economic region in the Gulf of Mexico and to the entire country. Mobile Bay was designated as an estuary of national significance in 1996. This estuary receives the fourth largest freshwater inflow in the United States. It provides vital nursery habitat for commercially and recreationally important fish species. It has exceptional aquatic and terrestrial bio-diversity, however, its estuary health is influenced by changing LULC patterns, such as urbanization. Mobile and Baldwin counties have experienced a population growth of 1.1% and 20.5% from 2000-2006. Urban expansion and population growth are likely to accelerate with the construction and operation of the ThyssenKrupp steel mill in the northeast portion of Mobile County. Land-use and land-cover change can negatively impact Gulf coast water quality and ecological resources. The conversion of forest to urban cover types impacts the carbon cycle and increases the freshwater and sediment in coastal waters. Increased freshwater runoff decreases salinity and increases the turbidity of coastal waters, thus impacting the growth potential of submerged aquatic vegetation (SAV), which is critical nursing ground for many Gulf fish species. A survey of Mobile Bay SAV showed widespread decreases since the 1940s. Prior to our project, coastal environmental managers in Baldwin and Mobile counties needed more understanding of the historical LULC for properly assessing the impacts of urbanization. In particular, more information on the location and extent of changing urbanization LULC patterns was needed to aid LULC planning and to assess predictions of future LULC patterns. Our products will assist the coastal environmental managers and land-use planners in making better community growth planning decisions. Our project also will help to establish a historical baseline of LULC distributions, which is a fundamental need in any stewardship plan. The primary research objective of our project was to produce historic and current geospatial LULC change products across a 34-year time frame. A multi-decadal coastal LULC change product was the major project deliverable. The geographic extent and nature of change was quantified and assessed for the upland herbaceous, barren, open water, urban, upland forest, woody wetland, and non-woody wetlanddominated land cover types. We focused on regional analyses of decadal-scale urban expansion and watershed-scaled analyses of LULC change for multiple areas of concern to the Mobile Bay NEP (Figure A). We used the following dates to derive LULC classification products from Landsat data: 1974, 1979, 1984, 1988, 1991, 1996, 2001, 2005, and 2008. We assessed the accuracy of our products using randomly sampled locations and digital geospatial reference data including field survey data, high resolution orthorectified aerial photography, high resolution multispectral and panchromatic satellite data displays (from QuickBird and Corona sensors), digital elevation model data, and National Wetlands Inventory wetland cover type data. NOAA s Coastal Change Assessment Program s (C-CAP) and National Land Cover Database (NLCD) procts were used for qualitative comparison in assessing map accuracy. We calculated an average overall classification accuracy of 87% with similar overall accuracies for the older (MSS) and newer (TM and ETM) Landsat LULC products
Inflationary Cosmological Perturbations of Quantum-Mechanical Origin
This review article aims at presenting the theory of inflation. We first
describe the background spacetime behavior during the slow-roll phase and
analyze how inflation ends and the Universe reheats. Then, we present the
theory of cosmological perturbations with special emphasis on their behavior
during inflation. In particular, we discuss the quantum-mechanical nature of
the fluctuations and show how the uncertainty principle fixes the amplitude of
the perturbations. In a next step, we calculate the inflationary power spectra
in the slow-roll approximation and compare these theoretical predictions to the
recent high accuracy measurements of the Cosmic Microwave Background radiation
(CMBR) anisotropy. We show how these data already constrain the underlying
inflationary high energy physics. Finally, we conclude with some speculations
about the trans-Planckian problem, arguing that this issue could allow us to
open a window on physical phenomena which have never been probed so far.Comment: Review Article, 47 pages, 3 figures. Lectures given at the 40th
Karpacz Winter School on Theoretical Physics (Poland, Feb. 2004), submitted
to Lecture Notes in Physic
Diversity Matters: Intersectionality and Women’s Descriptive Representation in the USA and UK
Women's organisations can help address some specific challenges faced by different groups of women during the political recruitment process. This article explores whether US and UK organisations do so. Legislative composition analysis confirms women of colour are under-represented, although they are better represented in the USA than in the UK; women with disabilities are under-represented in both countries, along with younger women in the USA and older women in the UK. Interviews with US women's organisations reveal a greater attention to diversity, particularly with regard to women of colour; however, the focus remains on increasing the overall number of women in both countries
Resonant conversions of extremely high energy neutrinos in dark matter halos
We study the effect of adiabatically resonant conversion in galactic halos of
neutrinos at the highest energies ( - eV), when the
source is in the center of a galaxy. Using the standard neutrino
properties and the standard cosmological scenario for the hot dark part of
matter, we find that interesting conversions may take place just for neutrino
parameters relevant to the solar and atmospheric neutrino problem. The effect
is due to the large enhancement in the density in galactic halos and to
the form of the effective matter potential both below and above the pole of the
resonance.Comment: 8 pages, revtex, some comments and references added, to appear in
Phys. Rev.
New Constraints on Neutralino Dark Matter in the Supersymmetric Standard Model
We investigate the prospects for neutralino dark matter within the
Supersymmetric Standard Model (SSM) including the constraints from universal
soft supersymmetry breaking and radiative breaking of the electroweak symmetry.
The latter is enforced by using the one-loop Higgs effective potential which
automatically gives the one-loop corrected Higgs boson masses. We perform an
exhaustive search of the allowed five-dimensional parameter space and find that
the neutralino relic abundance depends most strongly on the
ratio . For the relic abundance is almost
always much too large, whereas for the opposite occurs. For
there are wide ranges of the remaining parameters for which
. We also determine that m_{\tilde q}\gsim250\GeV and
m_{\tilde l}\gsim100\GeV are necessary in order to possibly achieve
. These lower bounds are much weaker than the corresponding
ones derived previously when radiative breaking was {\it not} enforced.Comment: 12 pages plus 6 figures (not included), CERN-TH.6584/92,
CTP-TAMU-56/92, UAHEP921
Scale-invariance of galaxy clustering
Some years ago we proposed a new approach to the analysis of galaxy and
cluster correlations based on the concepts and methods of modern statistical
Physics. This led to the surprising result that galaxy correlations are fractal
and not homogeneous up to the limits of the available catalogs. The usual
statistical methods, which are based on the assumption of homogeneity, are
therefore inconsistent for all the length scales probed so far, and a new, more
general, conceptual framework is necessary to identifythe real physical
properties of these structures. In the last few years the 3-d catalogs have
been significatively improved and we have extended our methods to the analysis
of number counts and angular catalogs. This has led to a complete analysis of
all the available data that we present in this review. The result is that
galaxy structures are highly irregular and self-similar: all the available data
are consistent with each other and show fractal correlations (with dimension ) up to the deepest scales probed so far (1000 \hmp) and even more
as indicated from the new interpretation of the number counts. The evidence for
scale-invariance of galaxy clustering is very strong up to 150 \hmp due to
the statistical robustness of the data but becomes progressively weaker
(statistically) at larger distances due to the limited data. In These facts
lead to fascinating conceptual implications about our knowledge of the universe
and to a new scenario for the theoretical challenge in this field.Comment: Latex file 165 pages, 106 postscript figures. This paper is also
available at http://www.phys.uniroma1.it/DOCS/PIL/pil.html To appear in
Physics Report (Dec. 1997
Diversity in Party Leadership in State Legislatures
Members of historically underrepresented groups—women, African Americans, Latinos, and workers—are serving in American legislatures in increasing numbers. However, legislators wield substantially greater power in the lawmaking process when they hold leadership positions. Incorporation of these groups into leadership positions could indicate fuller political representation, but scholars to date have not assessed how well these groups are represented in leadership. We analyze original data describing the backgrounds of approximately 2,200 leaders in 30 states between 2003 and 2014. The data show that, on average across states, members of these groups are as well represented in state legislative leadership positions as they are in rank-and-file membership, but there is substantial variation across states and across parties. We then ask what factors might explain this variation and explore institutional characteristics, like the number of leadership positions or leader selection methods. The results show that legislative chambers with a higher number of leadership posts tend to have more women in leadership, and that selection through elections is associated with decreased African American presence in leadership. The findings have implications for minority incorporation and influence in American politics
Pseudosmooth Tribrid Inflation
We explore a new class of supersymmetric models of inflation where the
inflaton is realised as a combination of a Higgs field and (gauge non-singlet)
matter fields, using a "tribrid" structure of the superpotential. Inflation is
associated with a phase transition around GUT scale energies. The inflationary
trajectory already preselects the later vacuum after inflation, which has the
advantage of automatically avoiding the production of dangerous topological
defects at the end of inflation. While at first sight the models look similar
to smooth inflation, they feature a waterfall and are therefore only
pseudosmooth. The new class of models offers novel possibilities for realising
inflation in close contact with particle physics, for instance with
supersymmetric GUTs or with supersymmetric flavour models based on family
symmetries.Comment: 16 pages, 5 figures. v2 matches publication in JCA
Manual / Issue 8 / Give and Take
Manual, a journal about art and its making. Give and Take. The eigth issue. Manual 8 (Give and Take) explores interaction, transaction, and social exchange and indebtedness.
The earliest known use of the expression “give and take” can be traced to horse racing. It referred to races in which larger, stronger horses carried more weight, and smaller ones, less. Implied therein is an accounting for relative capacities. In such a race, the goal remains the same—crossing the finish line first—but introducing this variable highlights the relationship between the competing horses. A win is only meaningful if each horse can be considered in relation to the others.
We . . . find ourselves in a historical moment that makes our interconnectedness both more visible and more complex. Boundaries—physical, geographical, ideological—have become more porous, and the institutions that have provided structure—while always deeply flawed—have shown themselves to be more vulnerable than some of us would have liked to believe. Old systems are breaking down, giving way. New ones will take hold. —Mary-Kim Arnold, from the introduction to Issue 8: Give and Takehttps://digitalcommons.risd.edu/risdmuseum_journals/1034/thumbnail.jp
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