[en] An important issue in supersymmetry phenomenology is the suppression of squarks contributions to Flavor Changing Neutral Currents (FCNC). Recently it was noted that in some free fermionic three generation models the anomalous U(1) is family universal. It was further shown that if the D-term of the U(1)_A is the dominant source of supersymmetry breaking, the squark masses are indeed approximately degenerate. In this paper the author discusses the properties of the superstring models that give rise to the flavor universal anomalous U(1). The root cause for the universal U(1)_A is the cyclic permutation symmetry, the characteristic property of the Z₂ X Z₂ orbifold compactification, realized in the free fermionic models by the NAHE set of boundary condition basis vectors. The properties of the three generation models that preserve this cyclic permutation symmetry in the flavor charges are discussed. The cyclic permutation symmetry of the Z₂ x Z₂ orbifold compactification is proposed to be the characteristic property, of phenomenological interest, that distinguishes it from other classes of superstring compactifications

[en] We construct a Landau-Ginzburg model with the same data and symmetries as a Z₂ x Z₂ orbifold that corresponds to a class of realistic free-fermion models. Within the class of interest, we show that this orbifolding connects between different Z₂ x Z₂ orbifold models and connects with the mirror symmetry. Our work suggests that duality symmetries previously discussed in the context of specific M and F theory compactifications may be extended to the special Z₂ x Z₂ orbifold that characterizes realistic free-fermion models

[en] This is the final report for DOE Grant DE-FG03-94ER6178, covering a performance period of 1 January 1994 through 31 December 1997. The DOE award amount for this period was $547,495. The objective of the project as stated in its proposal was open-quotes to improve our understanding of the physical processes controlling the concentration of radon, thoron, and their progeny in the atmospheric environment.close quotes The original project was directed at developing underlying science that would help with evaluation of the health hazard from indoor radon in the United States and implementation of corrective measures that might be employed to reduce the health hazard. As priorities within the Office of Health and Environment (OHER) changed, and the radon research program was phased out, emphasis of the project was shifted somewhat to be also relevant to other interests of the OHER, namely global pollution and climate change and pollution resulting from energy production. This final report is brief, since by reference it can direct the reader to the comprehensive research publications that have been generated by the project. In section 2, we summarize the main accomplishments of the project and reference the primary publications. There were seven students who received support from the project and their names are listed in section 3. One of these students (Fred Yarger, Ph.D. candidate) continues to work on research initiated through this project. No post-docs received support from the project, although one of the co-principal investigators (Dr. Piotr Wasiolek) received the majority of his salary from the project. The project also provided part-time support for a laboratory manager (Dr. Maryla Wasiolek). Section 4 lists chronologically the reports and publications resulting from the project (references 1 through 12), and the Appendix provides abstracts of major publications and reports

[en] This plan presents the characterization strategy for Corrective Action Unit (CAU) 109, U-2bu Subsidence Crater (referred to as U-2bu) in Area 2 at the Nevada Test Site (NTS). The objective of the planned activities is to obtain sufficient characterization data for the crater soils and observed wastes under the conditions of the current Resource Conservation and Recovery Act (RCRA) Part A permit. The scope of the characterization plan includes collecting surface and subsurface soil samples with hand augers and for the purpose of site characterization. The sampling strategy is to characterize the study area soils and look for RCRA constituents. Observable waste soils and surrounding crater soils will be analyzed and evaluated according to RCRA closure criteria. Because of the status of the crater a RCRA Part A permit site, acquired radionuclide analyses will only be evaluated in regards to the health and safety of site workers and the disposition of wastes generated during site characterization. The U-2bu Subsidence Crater was created in 1971 by a Lawrence Livermore National Laboratory underground nuclear test, event name Miniata, and was used as a land-disposal unit for radioactive and hazardous waste from 1973 to 1988

[en] This sampling and analysis plan (SAP) presents the rationale and strategy for the sampling and analysis activities proposed to be conducted to support the evaluation of alternatives for the final disposition of the 221-U Facility. This SAP will describe general sample locations and the minimum number of samples required. It will also identify the specific contaminants of potential concern (COPCs) and the required analysis. This SAP does not define the exact sample locations and equipment to be used in the field due to the nature of unknowns associated with the 221-U Facility

[en] Nuclear power in Finland was introduced in the late 1970 and early 1980. Presently around a fourth of the electric power in Finland is produced by four nuclear units at the Loviisa and Olkiluoto sites. The operational record has been excellent for all four plants. Presently ambitious Modernization projects have been initiated at all four plans which also aims at an increased power output. (author)

[en] Five nodulation-variants of chickpea (Cicer arietinum L.) cv. ICC 5003, delineated on the basis of visual ratings ('S1' for minimum nodulation to 'S5' for maximum), were used to investigate the optimum levels of nodulation and N₂ fixation for growth and yield. Two field experiments were conducted, with fertilizer N (enriched in ¹⁵N) applied at 10 ('N1') or 100 kg ha^-1 ('N2') on contrasting soils in different years; plants were evaluated for nodulation, growth, N₂ fixation and yield. Experiment 2 included high-nodulating (HN) and low-nodulating (LN) selections of cvv. ICC 4948, ICC 14196 and Kourinsky. Non-nodulating selections of chickpea were included as references to quantify N₂ fixation. In both experiments the trends in amounts of N fixed by the five selections at N1 were similar when assessed by ¹⁵N-enriched and by N-difference methods. The percent N derived from N₂ fixation (estimated from ¹⁵N data) correlated with yield and amount of N fixed in Experiment 2, but not Experiment 1. The relative nodulation differences were consistent across locations; the S4 and S5 (and HN) lines were generally superior to S1 and S2 (and LN) for nodulation, N₂-fixation, total dry matter and grain yield. Nodule number and mass correlated significantly (P<0.05) with total dry matter, grain yield, total N and quantity of N₂-fixed in both experiments

[en] It is well known that retardation effects are essential to allow the attractive part of the electron-electron interaction (for instance, phonon mediated) to overcome the Coulomb repulsion. In new superconductors such as the cuprates for which the interaction is a priori unknown, it is therefore essential to determine the retarded and non retarded parts of the interaction. We show how this can be achieved by an analysis of Sharvin contact measurements between a noble metal tip and a cuprate. It turns out that both the retarded and non retarded parts are large, the former being however larger than the later

[en] We investigate the changes of the total energy, the electronic bands, and the dielectric function with the displacement of the apical oxygen position in YBa₂Cu₃O₇ by LAPW-calculations. From these data we calculate the corresponding vibronic Raman-spectrum. Anharmonic terms of the vibrational potential and higher order derivatives of the dielectric function are taken into account. We find excellent agreement with experimental data for the phonon frequency as well as for the intensities of fundamental and overtone spectra within a wide temperature range

[en] Using pulsed Raman spectroscopy, we directly examined the intrinsic apical O potential in insulating YBa₂Cu₃O_6.25 and metallic YBa₂Cu₃O_6.9. We selectively excited the apical O vibration mode with ultra short laser pulses to obtain a 'hot' apical O vibration mode in a 'cold' bulk phonon background. Measurements showed that the apical O phonon frequency shift and linewidth change are much smaller in the case of selective heating of the apical O vibration mode compared to bulk heating. The results agree well with theoretical predictions and indicate a strong influence of surrounding lattice ions on the apical O potential. (author)