159 research outputs found
Regional Poverty and Population Response:A Comparison of Three Regions in the United States and Germany
In this paper, we examine poverty in three regions in the United States and Germany and discuss its causes and demographic consequences. The three regions are those with the highest rates of poverty in the two countries: the Mississippi Delta and Texas Borderland in the United States and the Northeastern Border Region in Germany. We show that standard models to explain poverty need to be placed in the historical legacies of the three regions in order to understand their current levels of poverty. While our results show many common factors for poverty in the three regions, they also point to important differences. Similarly, we identify differences among the regions in their demographic responses to poverty, in part reflecting their different historical legacies. Thus, one implication of the paper is the importance of place-based poverty-mitigation strategies for successful policy planning.In this paper, we examine poverty in three regions in the United States and Germany and discuss its causes and demographic consequences. The three regions are those with the highest rates of poverty in the two countries: the Mississippi Delta and Texas Borderland in the United States and the Northeastern Border Region in Germany. We show that standard models to explain poverty need to be placed in the historical legacies of the three regions in order to understand their current levels of poverty. While our results show many common factors for poverty in the three regions, they also point to important differences. Similarly, we identify differences among the regions in their demographic responses to poverty, in part reflecting their different historical legacies. Thus, one implication of the paper is the importance of place-based poverty-mitigation strategies for successful policy planning
BeppoSAX Observations of 2 Jy Lobe-dominated Broad-Line Sources: the Discovery of a Hard X-ray Component
We present new BeppoSAX LECS, MECS, and PDS observations of five
lobe-dominated, broad-line active galactic nuclei selected from the 2 Jy sample
of southern radio sources. These include three radio quasars and two broad-line
radio galaxies. ROSAT PSPC data, available for all the objects, are also used
to better constrain the spectral shape in the soft X-ray band. The collected
data cover the 0.1 - 10 keV energy range, reaching 40 keV for one source.
Detailed spectral fitting shows that all sources have a flat hard X-ray
spectrum with energy index alpha_x ~ 0.75 in the 2 - 10 keV energy range. This
is a new result, which is at variance with the situation at lower energies
where these sources exhibit steeper spectra. Spectral breaks ~0.5 at 1 - 2 keV
characterize the overall X-ray spectra of our objects. The flat, high-energy
slope is very similar to that displayed by flat-spectrum/core-dominated
quasars, which suggests that the same emission mechanism (most likely inverse
Compton) produces the hard X-ray spectra in both classes. Contrary to the
optical evidence for some of our sources, no absorption above the Galactic
value is found in our sample. Finally, a (weak) thermal component is also
present at low energies in the two broad-line radio galaxies included in our
study.Comment: 4 pages, LateX, 3 figures. Uses espcrc2.sty. To appear in: "The
Active X-ray Sky: Results from BeppoSAX and Rossi-XTE", Rome, Italy, 21-24
October, 1997, Eds.: L. Scarsi, H. Bradt, P. Giommi and F. Fior
Worker participation and firm performance : evidence from Germany and Britain
This paper examines the Freeman-Lazear works council/worker involvement model against the empirical backdrop of two different industrial relations systems: the British voluntaristic system, and the German system of mandatory works councils. We find that in nonunion British firms worker involvement increases economic performance, but in the union firms there are negative effects. The implication is that local distributive conflict can cause the wrong level of worker involvement to be chosen, as predicted by the model. ln Germany, where centralized collective bargaining reduces local distributive conflict, we find that a mandate can be advantageous, again as predicted by the model. However, the straitjacket of a mandate is shown to disadvantage small German firms
Towards defining the role of glycans as hardware in information storage and transfer: Basic principles, experimental approaches and recent progress
The term `code' in biological information transfer appears to be tightly and hitherto exclusively connected with the genetic code based on nucleotides and translated into functional activities via proteins. However, the recent appreciation of the enormous coding capacity of oligosaccharide chains of natural glycoconjugates has spurred to give heed to a new concept: versatile glycan assembly by the genetically encoded glycosyltransferases endows cells with a probably not yet fully catalogued array of meaningful messages. Enciphered by sugar receptors such as endogenous lectins the information of code words established by a series of covalently linked monosaccharides as fetters for example guides correct intra- and intercellular routing of glycoproteins, modulates cell proliferation or migration and mediates cell adhesion. Evidently, the elucidation of the structural frameworks and the recognition strategies within the operation of the sugar code poses a fascinating conundrum. The far-reaching impact of this recognition mode on the level of cells, tissues and organs has fueled vigorous investigations to probe the subtleties of protein-carbohydrate interactions. This review presents information on the necessarily concerted approach using X-ray crystallography, molecular modeling, nuclear magnetic resonance spectroscopy, thermodynamic analysis and engineered ligands and receptors. This part of the treatise is flanked by exemplarily chosen insights made possible by these techniques. Copyright (C) 2001 S. Karger AG, Basel
No significantly increased frequency of the inversion polymorphism at the WBS-critical region 7q11.23 in German parents of patients with Williams-Beuren syndrome as compared to a population control
<p>Abstract</p> <p>Background</p> <p>Typical Williams-Beuren syndrome (WBS) is commonly caused by a ~1.5 Mb - ~1.8 Mb heterozygous deletion of contiguous genes at chromosome region 7q11.23. The majority of WBS cases occurs sporadically but few familial cases of autosomal dominant inheritance have been reported. Recent data demonstrated the existence of the paracentric inversion polymorphism at the WBS critical region in 7q11.23 in some of the progenitors transmitting the chromosome which shows the deletion in the affected child. In parents having a child affected by WBS the prevalence of such a structural variant has been reported to be much higher (~25- ~30%) than in the general population (~1- ~6%). However, in these previously reported studies only a limited number of randomly selected patients and non transmitting parents of WBS patients were used as controls, but without specification of any clinical data. Therefore we have undertaken a German population-based molecular cytogenetic investigation. We evaluated the incidence of the paracentric inversion polymorphism at 7q11.23 analyzing interphase nuclei of lymphocytes using a three color fluorescence in situ hybridization (FISH) probe.</p> <p>Results</p> <p>FISH analysis was carried out on couples with a child affected by WBS as compared to a population sample composed of different normal individuals: Control group I: couples with two healthy children, control group II: couples with fertility problems, planning ICSI and control group III: couples with two healthy children and one child with a chromosome aberration, not involving region 7q11.23. The three color FISH assay showed that the frequency of the paracentric inversion polymorphism at 7q11.23 in couples with a child affected by WBS was 20.8% (5 out of 24 pairs) as compared to 8.3% (2 out of 24 pairs, control group I), 25% (4 out of 16 pairs, control group II) and 9.1% (1 out of 11 pairs, control group III), respectively (total 7 out of 51 pairs, 13.8%). The frequencies differed between the groups, but this was statistically not significant (p > 0.05, Fisher's test).</p> <p>Conclusion</p> <p>Our results do not support the hypothesis that the paracentric inversion polymorphism at 7q11.23 is a major predisposing factor for the WBS deletion.</p
Lectin ligands: New insights into their conformations and their dynamic behavior and the discovery of conformer selection by lectins
The mysteries of the functions of complex glycoconjugates have enthralled scientists over decades. Theoretical considerations have ascribed an enormous capacity to store information to oligosaccharides, In the interplay with lectins sugar-code words of complex carbohydrate structures can be deciphered. To capitalize on knowledge about this type of molecular recognition for rational marker/drug design, the intimate details of the recognition process must be delineated, To this aim the required approach is garnered from several fields, profiting from advances primarily in X-ray crystallography, nuclear magnetic resonance spectroscopy and computational calculations encompassing molecular mechanics, molecular dynamics and homology modeling. Collectively considered, the results force us to jettison the preconception of a rigid ligand structure. On the contrary, a carbohydrate ligand may move rather freely between two or even more low-energy positions, affording the basis for conformer selection by a lectin. By an exemplary illustration of the interdisciplinary approach including up-to-date refinements in carbohydrate modeling it is underscored why this combination is considered to show promise of fostering innovative strategies in rational marker/drug design
On the role of data, statistics and decisions in a pandemic
A pandemic poses particular challenges to decision-making because of the need
to continuously adapt decisions to rapidly changing evidence and available
data. For example, which countermeasures are appropriate at a particular stage
of the pandemic? How can the severity of the pandemic be measured? What is the
effect of vaccination in the population and which groups should be vaccinated
first? The process of decision-making starts with data collection and modeling
and continues to the dissemination of results and the subsequent decisions
taken. The goal of this paper is to give an overview of this process and to
provide recommendations for the different steps from a statistical perspective.
In particular, we discuss a range of modeling techniques including
mathematical, statistical and decision-analytic models along with their
applications in the COVID-19 context. With this overview, we aim to foster the
understanding of the goals of these modeling approaches and the specific data
requirements that are essential for the interpretation of results and for
successful interdisciplinary collaborations. A special focus is on the role
played by data in these different models, and we incorporate into the
discussion the importance of statistical literacy, and of effective
dissemination and communication of findings
Authors' response: on the role of data, statistics and decisions in a pandemic
"We would like to thank the discussants once more for adding their thoughtful comments.
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