High-energy electron-induced damage production at room temperature in aluminum-doped silicon

DLTS and EPR measurements are reported on aluminum-doped silicon that was irradiated at room temperature with high-energy electrons. Comparisons are made to comparable experiments on boron-doped silicon. Many of the same defects observed in boron-doped silicon are also observed in aluminum-doped silicon, but several others were not observed, including the aluminum interstitial and aluminum-associated defects. Damage production modeling, including the dependence on aluminum concentration, is presented

Studentification And Off-Campus Housing: A Case Study Of Grand Forks Near-Campus Neighborhoods

With national trends in higher education experiencing dwindling enrollments and personal economies increasingly strained, the University of North Dakota (UND) has grown to become the biggest public higher education institution in North Dakota, having effectively bounced back from the COVID-19 pandemic drop in enrollment. Grand Forks, North Dakota, is the host of UND and home to a student body of over 14,000 as of 2023 fall semester. This study focuses on; to what extent is studentification taking place in Grand Forks, ND; and how the observed housing- and demographic patterns in Grand Forks align with, or diverge from, the broader theoretical conceptualization of studentification. First, a spatial analysis, applying spatial autocorrelation methods Global Moran’s I and Local Moran’s I in ArcGIS Pro is conducted. The analysis reveals an increase in clustering across the study period, concentrating in the near-campus neighborhoods. Second, Multiple Linear Regression and Geographically Weighted Regression identify the driving factors to student housing choices based on the effects of studentification identified in the literature, identifying affordability, rental availability, and newer housing stock as deciding factors to student clustering. The results contribute to furthering the conceptualization of studentification and student geographies in nonmetropolitan college towns in the United States

Carbon credit card services and the impact potential on Co2 emissions in the Eu - conceptualization of a Co2 reduction impact model

Section 3 presents a conceptual overview of the CO2 Reduction Impact Model. The model aims to investigate the reduction potential of EU carbon emissions over the next ten years by the adoption of Carbon Credit Card Services. Three scenarios have been developed to determine the impact potential based on different levels of improved sustainable behavior by users. The three scenarios are then impacted by three main factors: emission development, user development and behavior & adaption. Additionally, personas with individual behaviors are generated to represent the EU population. By improved sustainable behavior among the personas, the impact of Carbon Credit Card Services increases

Radiation Induced Point and Cluster-Related Defects with Strong Impact to Damage Properties of Silicon Detectors

This work focuses on the investigation of radiation induced defects responsible for the degradation of silicon detectors. Comparative studies of the defects induced by irradiation with 60Co- rays, 6 and 15 MeV electrons, 23 GeV protons and 1 MeV equivalent reactor neutrons revealed the existence of point defects and cluster related centers having a strong impact on damage properties of Si diodes. The detailed relation between the microscopic reasons as based on defect analysis and their macroscopic consequences for detector performance are presented. In particular, it is shown that the changes in the Si device properties after exposure to high levels of 60Co- doses can be completely understood by the formation of two point defects, both depending strongly on the Oxygen concentration in the silicon bulk. Specific for hadron irradiation are the annealing effects which decrease resp. increase the originally observed damage effects as seen by the changes of the depletion voltage. A group of three cluster related defects, revealed as deep hole traps, proved to be responsible specifically for the reverse annealing. Their formation is not affected by the Oxygen content or Si growth procedure suggesting that they are complexes of multi-vacancies located inside extended disordered regions.Comment: 14 pages, 15 figure

A Search for Selectrons and Squarks at HERA

Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure

Differential (2+1) Jet Event Rates and Determination of alpha_s in Deep Inelastic Scattering at HERA

Events with a (2+1) jet topology in deep-inelastic scattering at HERA are studied in the kinematic range 200 < Q^2< 10,000 GeV^2. The rate of (2+1) jet events has been determined with the modified JADE jet algorithm as a function of the jet resolution parameter and is compared with the predictions of Monte Carlo models. In addition, the event rate is corrected for both hadronization and detector effects and is compared with next-to-leading order QCD calculations. A value of the strong coupling constant of alpha_s(M_Z^2)= 0.118+- 0.002 (stat.)^(+0.007)_(-0.008) (syst.)^(+0.007)_(-0.006) (theory) is extracted. The systematic error includes uncertainties in the calorimeter energy calibration, in the description of the data by current Monte Carlo models, and in the knowledge of the parton densities. The theoretical error is dominated by the renormalization scale ambiguity.Comment: 25 pages, 6 figures, 3 tables, submitted to Eur. Phys.

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil

Multiplicity Structure of the Hadronic Final State in Diffractive Deep-Inelastic Scattering at HERA

The multiplicity structure of the hadronic system X produced in deep-inelastic processes at HERA of the type ep -> eXY, where Y is a hadronic system with mass M_Y< 1.6 GeV and where the squared momentum transfer at the pY vertex, t, is limited to |t|<1 GeV^2, is studied as a function of the invariant mass M_X of the system X. Results are presented on multiplicity distributions and multiplicity moments, rapidity spectra and forward-backward correlations in the centre-of-mass system of X. The data are compared to results in e+e- annihilation, fixed-target lepton-nucleon collisions, hadro-produced diffractive final states and to non-diffractive hadron-hadron collisions. The comparison suggests a production mechanism of virtual photon dissociation which involves a mixture of partonic states and a significant gluon content. The data are well described by a model, based on a QCD-Regge analysis of the diffractive structure function, which assumes a large hard gluonic component of the colourless exchange at low Q^2. A model with soft colour interactions is also successful.Comment: 22 pages, 4 figures, submitted to Eur. Phys. J., error in first submission - omitted bibliograph

Finnish Companies' Business Operations in the Baltic Sea Region: Locational Sources of Firm-Specific Competitiveness

The paper analyzes the locational sources of firm-specific competitive advantages of Finnish companies in the Baltic Sea region. Views of managers responsible for foreign operations in 100 Finnish companies form the base of the study organized in systematic way in the framework of a survey and interviews conducted in Finland in the Spring of 2002. The analysis of the survey data is implemented via statistical analysis. Evidence was found for the claim that a major part of the Finnish companies' created assets, especially technological ones, are of home country origin. Nevertheless, certain other sources of competitiveness, such as consumer demand for upgraded product quality; inter-firm competition; and links with companies operating in the same industry are originating to a significant extent in other Baltic Rim countries, especially EU member countries. It was also found that technology intensity and the degree of transnationality of the companies are company characteristics that explain to what extent companies are taking advantage of foreign sources of competitiveness

Cervical spine reposition errors after cervical flexion and extension

BACKGROUND: Upright head and neck position has been frequently applied as baseline for diagnosis of neck problems. However, the variance of the position after cervical motions has never been demonstrated. Thus, it is unclear if the baseline position varies evenly across the cervical joints. The purpose was to assess reposition errors of upright cervical spine. METHODS: Cervical reposition errors were measured in twenty healthy subjects (6 females) using video-fluoroscopy. Two flexion movements were performed with a 20 s interval, the same was repeated for extension, with an interval of 5 min between flexion and extension movements. Cervical joint positions were assessed with anatomical landmarks and external markers in a Matlab program. Reposition errors were extracted in degrees (initial position minus reposition) as constant errors (CEs) and absolute errors (AEs). RESULTS: Twelve of twenty-eight CEs (7 joints times 4 repositions) exceeded the minimal detectable change (MDC), while all AEs exceeded the MDC. Averaged AEs across the cervical joints were larger after 5 min’ intervals compared to 20 s intervals (p < 0.05). CONCLUSIONS: This is the first study to demonstrate single joint reposition errors of the cervical spine. The cervical spine returns to the upright positions with a 2° average absolute difference after cervical flexion and extension movements in healthy adults. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12891-017-1454-z) contains supplementary material, which is available to authorized users