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Search Results: 1 - 10 of 2811 matches for " Joachim "
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The Origin of the Giant Hall Effect in Metal-Insulator Composites  [PDF]
Joachim Sonntag
Open Journal of Composite Materials (OJCM) , 2016, DOI: 10.4236/ojcm.2016.63008
Abstract: Near the metal-insulator transition, the Hall coefficient R of metal-insulator composites (M-I composite) can be up to 104 times larger than that in the pure metal called Giant Hall effect. Applying the physical model for alloys with phase separation developed in [1] [2], we conclude that the Giant Hall effect is caused by an electron transfer away from the metallic phase to the insulating phase occupying surface states. These surface states are the reason for the granular structure typical for M-I composites. This electron transfer can be described by \"\" [1] [2], provided that long-range diffusion does not happen during film production (n is the electron density in the phase A. uA?and uB are the volume fractions of the phase A (metallic phase) and phase B (insulator phase). β is a measure for the average potential difference between the phases A and B). A formula for calculation of R of composites is derived and applied to experimental data of granular Cu1-y(SiO2)y and Ni1-y(SiO2)y films.
On the Universal Mechanism Underlying Conscious Systems and the Foundations for a Theory of Consciousness  [PDF]
Joachim Keppler
Open Journal of Philosophy (OJPP) , 2016, DOI: 10.4236/ojpp.2016.64034
Abstract: In this article, I present a novel approach to the scientific understanding of consciousness. It is based on the hypothesis that the full range of phenomenal qualities is built into the frequency spectrum of a ubiquitous background field and proceeds on the assumption that conscious systems employ a universal mechanism by means of which they are able to extract phenomenal nuances selectively from this field. I set forth that in the form of the zero-point field (ZPF) physics can offer a promising candidate that is qualified for playing the dual role as both the carrier of energy and consciousness. The appropriate mechanism, which rests upon the principle of dynamical coupling of ZPF modes, is a unique feature of quantum systems, suggesting that the dividing line between conscious and non-conscious systems is defined by the differentiation between quantum systems and classical systems. The presence of this mechanism in the brain is supported by the neurophysiological body of evidence, leading to a consistent explanation of the dynamical properties of the neural correlates of consciousness. Building on these findings, I lay the foundations for the conceptually coherent integration of consciousness into the physical worldview, derive an indicator for the quantity of consciousness of a given system, and outline the further steps toward a theory of consciousness.
Advances in MIMO Techniques for Mobile Communications—A Survey  [PDF]
Farhan Khalid, Joachim Speidel
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.33031
Abstract: This paper provides a comprehensive overview of critical developments in the field of multiple-input multiple-output (MIMO) wireless communication systems. The state of the art in single-user MIMO (SU-MIMO) and multiuser MIMO (MU-MIMO) communications is presented, highlighting the key aspects of these technologies. Both open-loop and closed-loop SU-MIMO systems are discussed in this paper with particular emphasis on the data rate maximization aspect of MIMO. A detailed review of various MU-MIMO uplink and downlink techniques then follows, clarifying the underlying concepts and emphasizing the importance of MU-MIMO in cellular communication systems. This paper also touches upon the topic of MU-MIMO capacity as well as the promising convex optimization approaches to MIMO system design.
Population Ageing and Capital Accumulation: A Simple OLG Model with PAYGO Pensions  [PDF]
Joachim Th?gersen
Theoretical Economics Letters (TEL) , 2015, DOI: 10.4236/tel.2015.52019
Abstract: Population in developed countries has dramatically aged in recent years. At the same time, most of these countries finance their old-age public pension benefits on a pay-as-you-go (PAYGO) basis. Such a pension scheme combined with an ageing population, represent a financial challenge for the governmental budgets. Accordingly, several studies have been done on the effects of population ageing. In the present paper, the purpose is to study how population ageing will affect capital accumulation. A simple OLG model with PAYGO pension is applied. The formulation of the model makes it possible to deduce an explicit expression for this relation. It is shown that an increase in the elderly dependency ratio will increase the long-run capital stock.
Hospital Employer Attractiveness Considering the Increasing Shortage of Skilled Medical Professionals—A German Review  [PDF]
Joachim Merk, Anke Rahmel
Journal of Biosciences and Medicines (JBM) , 2016, DOI: 10.4236/jbm.2016.412001
The main goal of this review is to give an overview of scientific publications concerning the employer attractiveness of German hospitals from the perspective of medical doctors in order to identify future research possibilities. After a summary of central problems concerning the German health sector and its current challenges, the study design behind the systematic content analysis as well as its criteria are presented. Selected results describe characteristics of expert literature for employer attractiveness in general, the attractiveness of German hospitals as employers (“hospital employer attractiveness” for short) as well as employer attractiveness from a medical doctor’s point of view. For each of these areas, focal points of research and main results are summarized and research gaps are pointed out.
Effect of NaCl-Induced Salinity and Human Urine Fertilization on Substrate Chemical Properties  [PDF]
Michael Yongha Boh, Joachim Sauerborn
Open Journal of Soil Science (OJSS) , 2014, DOI: 10.4236/ojss.2014.41003

We evaluated the effect of NaCl-induced salinity and successive urine fertilization on changes in cultivation substrate chemical properties in a greenhouse study. The substrate was composed of an equal volume ratio mixture of bio-waste compost, quartz sand and silty loam soil. Salinity was imitated by adding NaCl solutions to a known substrate weight achieving three target salinity treatments of ECe 1.3 (S0—no NaCl), 4.6 (S1) and 7.6 (S2) dS·m-1. Cultivation substrate had been cropped with two cycles of maize (Zea mays L.) (crop cycles I and II) and fertilized with human urine at N amounts of 0 (U0—no urine), 180 (U1) and 360 (U2) mg·kg-1 substrate in the first cycle and half of the urine-N dosages in cycle II. Substrate samples collected at the end of each cycle were analyzed for pHKCl, ECe, exchangeable and water extractable cations (Na+, K+, Ca2+, Mg2+), cation exchange capacity, water extractable anions (Cl-, \"\", \"\",\"\" ) and exchangeable sodium percentage (ESP). Exchangeable Na+, K+ and Ca2+ were significantly (p < 0.05) affected by salinity x urine interaction. ECe significantly increased by 7.3, 5.3 and 7.6 dS·m-1 in the S0, S1 and S2 treatments following an increase in urine from U0 to U2. In the S0 treatment, ESP increased in the order U0 < U1 < U2. Extractable \"\" and Cl- were significantly affected by crop cycle, salinity and urine interactions (p < 0.05) whereas the effect of urine fertilizer on extractable \"\" and \"\"

A Multiscale Assessment of the Risks Imposed by Plantation Forestry on Plant Biodiversity in the Hotspot Central Chile  [PDF]
Andreas Ch. Braun, Joachim Vogt
Open Journal of Ecology (OJE) , 2014, DOI: 10.4236/oje.2014.416085

We assessed the effects of plantations of exotic trees (Pinus radiata, Eucalyptus globulus, and Populus nigra) on plant biodiversity in the temperate zone of the biodiversity hotspot of Central Chile. This region has suffered from intense deforestation in favor of plantation establishment in the major part of the coastal area since the neoliberal turn in 1973. The approach presented aimed to analyze plant biodiversity on the α-, β- and γ-scale. Furthermore, a plantation evaluation index was applied in order to provide quantitative figures on management practices. Species richness is reduced by 50% below plantations. Diversity and evenness index values are also significantly reduced. Analyses on β-similarity indicate that plantations do not host species absent in adjacent native forests, and no additional habitat heterogeneity is gained. On the γ-scale, plantations lower the number of total species observed; especially of endemic species. The abundance of species considered as invasive is significantly higher and frequently, invasive plants dominate the understory. The evaluation index attests rather poor plantation management in Central Chile since plantations are grown as monocultures, natural elements and native species are lacking at specific sites and plantations are insufficiently connected to native plant formations at the landscape scale. Results give

Laplace–Fourier Transform of the Stretched Exponential Function: Analytic Error Bounds, Double Exponential Transform, and Open-Source Implementation “libkww”
Joachim Wuttke
Algorithms , 2012, DOI: 10.3390/a5040604
Abstract: The C library libkww provides functions to compute the Kohlrausch–Williams– Watts function, i.e., the Laplace–Fourier transform of the stretched (or compressed) exponential function exp(- t β ) for exponents β between 0.1 and 1.9 with double precision. Analytic error bounds are derived for the low and high frequency series expansions. For intermediate frequencies, the numeric integration is enormously accelerated by using the Ooura–Mori double exponential transformation. The primitive of the cosine transform needed for the convolution integrals is also implemented. The software is hosted at http://apps.jcns.fz-juelich.de/kww; version 3.0 is deposited as supplementary material to this article.
Successful Smoking Cessation and Duration of Abstinence—An Analysis of Socioeconomic Determinants
Joachim Marti
International Journal of Environmental Research and Public Health , 2010, DOI: 10.3390/ijerph7072789
Abstract: Smoking does not affect every socioeconomic subgroup of the population equally, resulting in major inequalities in terms of smoking-related morbidity and mortality. While previous studies mainly focused on inequalities in smoking prevalence, we have analysed the socioeconomic dimensions that might be associated with two other smoking-related outcomes: the odds of successfully quitting and the duration of abstinence. Using nationally representative Swiss data, we found evidence of a socioeconomic gradient in successful cessation and abstinence duration with respect to education level and income for both men and women.
Developments in the scientific and clinical understanding of the spondyloarthritides
Joachim Sieper
Arthritis Research & Therapy , 2009, DOI: 10.1186/ar2562
Abstract: In the last decade, there has been an unprecedented rapid development in nearly all clinical and scientific aspects of the spondyloarthritides (SpA) which was stimulated, at least in part, by the unexpectedly good efficacy of tumor necrosis factor (TNF) blocker treatment in these patients. Along with the availability of new treatment options have come the establishment of magnetic resonance imaging (MRI) as an essential tool for better and earlier diagnosis, for follow-up of patients, and for a better understanding of the pathogenesis of this disease, the definitions of new management criteria and outcome criteria by the Assessment in SpondyloArthritis International Society (ASAS), and the recognition of the unmet need to diagnose SpA patients earlier, to develop better criteria for early diagnosis, and finally to get a better understanding of the pathogenetic mechanisms in SpA. The research and the rapid development in the last 10 years have been preferentially focused on axial SpA, with ankylosing spondylitis (AS) as the most relevant subtype. Considerable progress could also be made in psoriatic arthritis (PsA), which overlaps with the SpA group. However, a thorough discussion of these results would go beyond the scope of this article and will have to be dealt with elsewhere. Therefore, the following discussion will focus on axial SpA and will touch only briefly on peripheral SpA.The SpA comprise AS, reactive arthritis, arthritis/spondylitis associated with psoriasis, and arthritis/spondylitis associated with inflammatory bowel disease (IBD). The main links between these conditions are the association with HLA-B27, the same pattern of peripheral joint involvement with an asymmetrical pauciarticular arthritis predominantly of the lower limbs, and the possible occurrence of sacroiliitis, spondylitis, enthesitis, dactylitis, and uveitis [1]. The SpA can also be divided into patients with predominantly axial and predominantly peripheral SpA, a classification that is
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