Massless minimally coupled fields in de Sitter space: O(4)-symmetric states versus de Sitter invariant vacuum

The issue of de Sitter invariance for a massless minimally coupled scalar field is examined. Formally, it is possible to construct a de Sitterinvariant state for this case provided that the zero mode of the field is quantized properly. Here we take the point of view that this state is physically acceptable, in the sense that physical observables can be computed and have a reasonable interpretation. In particular, we use this vacuum to derive a new result: that the squared difference between the field at two points along a geodesic observers spacetime path grows linearly with the observers proper time for a quantum state that does not break de Sitter invariance. Also, we use the Hadamard formalism to compute the renormalized expectation value of the energy-momentum tensor, both in the O(4)-invariant states introduced by Allen and Follaci, and in the de Sitterinvariant vacuum. We find that the vacuum energy density in the O(4)-invariant case is larger than in the de Sitterinvariant case.

Nucleation rates in flat and curved space

Nucleation rates for tunneling processes in Minkowski and de Sitter space are investigated, taking into account one loop prefactors. In particular, we consider the creation of membranes by an antisymmetric tensor field, analogous to Schwinger pair production. This can be viewed as a model for the decay of a false (or true) vacuum at zero temperature in the thin wall limit. Also considered is the spontaneous nucleation of strings, domain walls, and monopoles during inflation. The instantons for these processes are spherical world sheets or world lines embedded in flat or de Sitter backgrounds. We find the contribution of such instantons to the semiclassical partition function, including the one loop corrections due to small fluctuations around the spherical world sheet. We suggest a prescription for obtaining, from the partition function, the distribution of objects nucleated during inflation. This can be seen as an extension of the usual formula, valid in flat space, according to which the nucleation rate is twice the imaginary part of the free energy. For the case of pair production, the results reproduce those that can be obtained using second quantization methods, confirming the validity of instanton techniques in de Sitter space. Throughout the paper, both the gravitational field and the antisymmetric tensor field are assumed external.

Pair production by and electric field in (1+1)-dimensional de Sitter space

We use the method of Bogolubov transformations to compute the rate of pair production by an electric field in (1+1)-dimensional de Sitter space. The results are in agreement with those obtained previously using the instanton methods. This is true even when the size of the instanton is comparable to the size of the de Sitter horizon.

Heat kernels and thermodynamics in Rindler space

We point out that using the heat kernel on a cone to compute the first quantum correction to the entropy of Rindler space does not yield the correct temperature dependence. In order to obtain the physics at arbitrary temperature one must compute the heat kernel in a geometry with different topology (without a conical singularity). This is done in two ways, which are shown to agree with computations performed by other methods. Also, we discuss the ambiguities in the regularization procedure and their physical consequences.

A Local DLP-GIS-LP system for geographically decentralized wood procurement planning and decision making

Summary

Singularity-free space-time

We show that the solution published in the paper by Senovilla [Phys. Rev. Lett. 64, 2219 (1990)] is geodesically complete and singularity-free. We also prove that the solution satisfies the stronger energy and causality conditions, such as global hyperbolicity, the strong energy condition, causal symmetry, and causal stability. A detailed discussion about which assumptions in the singularity theorems are not satisfied is performed, and we show explicitly that the solution is in accordance with those theorems. A brief discussion of the results is given.

Final planning report for City of Urbandale, Iowa,1962.

This is a three volume set of the final report on the comprehensive plan of the Urban Planning Grant for the City of Urbandale. The report also includes important maps and charts.

2005 Annual Report Capitol Planning Commission, January 2005

The Capitol Planning Commission is authorized under Chapter 8A.371—378 of the Code of Iowa. “It shall be the duty of the commission to advise upon the location of statues, fountains and monuments and the placing of any additional buildings on the capitol grounds, the type of architecture and the type of construction of any new buildings to be erected on the state capitol grounds as now encompassed or as subsequently enlarged, and repairs and restoration thereof, and it shall be the duty of the officers, commissions, and councils charged by law with the duty of determining such questions to call upon the commission for such advice. “The commission shall, in cooperation with the director of the department of administrative services, develop and implement within the limits of its appropriation, a five-year modernization program for the capitol complex. “The commission shall annually report to the general assembly its recommendations relating to its duties under this section. The report shall be submitted to the chief clerk of the house and the secretary of the senate during the month of January.” —Code of Iowa, Chapter 8A.373

2006 Annual Report Capitol Planning Commission, April 2006

The Capitol Planning Commission is authorized under Chapter 8A.371—378 of the Code of Iowa. “It shall be the duty of the commission to advise upon the location of statues, fountains and monuments and the placing of any additional buildings on the capitol grounds, the type of architecture and the type of construction of any new buildings to be erected on the state capitol grounds as now encompassed or as subsequently enlarged, and repairs and restoration thereof, and it shall be the duty of the officers, commissions, and councils charged by law with the duty of determining such questions to call upon the commission for such advice. “The commission shall, in cooperation with the director of the department of administrative services, develop and implement within the limits of its appropriation, a five-year modernization program for the capitol complex. “The commission shall annually report to the general assembly its recommendations relating to its duties under this section. The report shall be submitted to the chief clerk of the house and the secretary of the senate during the month of January.” —Code of Iowa, Chapter 8A.373

2007 Annual Report Capitol Planning Commission, January 2008

The Capitol Planning Commission is authorized under Chapter 8A.371—378 of the Code of Iowa. “It shall be the duty of the commission to advise upon the location of statues, fountains and monuments and the placing of any additional buildings on the capitol grounds, the type of architecture and the type of construction of any new buildings to be erected on the state capitol grounds as now encompassed or as subsequently enlarged, and repairs and restoration thereof, and it shall be the duty of the officers, commissions, and councils charged by law with the duty of determining such questions to call upon the commission for such advice. “The commission shall, in cooperation with the director of the department of administrative services, develop and implement within the limits of its appropriation, a five-year modernization program for the capitol complex. “The commission shall annually report to the general assembly its recommendations relating to its duties under this section. The report shall be submitted to the chief clerk of the house and the secretary of the senate during the month of January.” —Code of Iowa, Chapter 8A.373

2010 Annual Report Capitol Planning Commission, January 2011

The Capitol Planning Commission is authorized under Chapter 8A.371—378 of the Code of Iowa. “It shall be the duty of the commission to advise upon the location of statues, fountains and monuments and the placing of any additional buildings on the capitol grounds, the type of architecture and the type of construction of any new buildings to be erected on the state capitol grounds as now encompassed or as subsequently enlarged, and repairs and restoration thereof, and it shall be the duty of the officers, commissions, and councils charged by law with the duty of determining such questions to call upon the commission for such advice. “The commission shall, in cooperation with the director of the department of administrative services, develop and implement within the limits of its appropriation, a five-year modernization program for the capitol complex. “The commission shall annually report to the general assembly its recommendations relating to its duties under this section. The report shall be submitted to the chief clerk of the house and the secretary of the senate during the month of January.” —Code of Iowa, Chapter 8A.373

2009 Annual Report Capitol Planning Commission, January 2010

This 2011 Annual Report further summarizes the work of the Commission during the last year and provides planning recommendations for the future of the Capitol Complex. Please note that Iowa Code Chapter 8A.373 provides that before any physical changes are made to the state capitol complex "it shall be the duty of the officers, commissions, and councils charged by law with the duty of determining such questions to call upon" the Capitol Planning Commission for advice. The Capitol Planning Commission members, as well as DAS Staff, welcome the opportunity to discuss future projects at the request of any legislator.

USE OF SCALED SEMIVARIOGRAMS IN THE PLANNING SAMPLE OF SOIL PHYSICAL PROPERTIES IN SOUTHERN AMAZONAS, BRAZIL

There is a great lack of information from soil surveys in the southern part of the State of Amazonas, Brazil. The use of tools such as geostatistics may improve environmental planning, use and management. In this study, we aimed to use scaled semivariograms in sample design of soil physical properties of some environments in Amazonas. We selected five areas located in the south of the state of Amazonas, Brazil, with varied soil uses, such as forest, archaeological dark earth (ADE), pasture, sugarcane cropping, and agroforestry. Regular mesh grids were set up in these areas with 64 sample points spaced at 10 m from each other. At these points, we determined the particle size composition, soil resistance to penetration, moisture, soil bulk density and particle density, macroporosity, microporosity, total porosity, and aggregate stability in water at a depth of 0.00-0.20 m. Descriptive and geostatistical analyses were performed. The sample density requirements were lower in the pasture area but higher in the forest. We concluded that managed-environments had differences in their soil physical properties compared to the natural forest; notably, the soil in the ADE environment is physically improved in relation to the others. The physical properties evaluated showed a structure of spatial dependence with a slight variability of the forest compared to the others. The use of the range parameter of the semivariogram analysis proved to be effective in determining an ideal sample density.

USE OF SCALED SEMIVARIOGRAMS IN THE PLANNING SAMPLE OF SOIL CHEMICAL PROPERTIES IN SOUTHERN AMAZONAS, BRAZIL

The lack of information concerning the variability of soil properties has been a major concern of researchers in the Amazon region. Thus, the aim of this study was to evaluate the spatial variability of soil chemical properties and determine minimal sampling density to characterize the variability of these properties in five environments located in the south of the State of Amazonas, Brazil. The five environments were archaeological dark earth (ADE), forest, pasture land, agroforestry operation, and sugarcane crop. Regular 70 × 70 m mesh grids were set up in these areas, with 64 sample points spaced at 10 m distance. Soil samples were collected at the 0.0-0.1 m depth. The chemical properties of pH in water, OM, P, K, Ca, Mg, H+Al, SB, CEC, and V were determined at these points. Data were analyzed by descriptive and geostatistical analyses. A large part of the data analyzed showed spatial dependence. Chemical properties were best fitted to the spherical model in almost all the environments evaluated, except for the sugarcane field with a better fit to the exponential model. ADE and sugarcane areas had greater heterogeneity of soil chemical properties, showing a greater range and higher sampling density; however, forest and agroforestry areas had less variability of chemical properties.