738 research outputs found
Serologic Response and Antibody-Titer Decay in Adults with Pertussis
Pertussis is a frequent and significant illness in adults. Because acellular pertussis vaccines for use in adolescents and adults have now been developed, it is important to compare serologic responses in adults after infection with serologic responses in adults after vaccination. We measured IgG and IgA antibodies to 4 Bordetella pertussis antigens at ā¼6-month intervals for 28 months in 11 adults with pertussis. After reaching peak levels, titers of antibody to pertussis toxin decreased more than did titers of antibodies to filamentous hemagglutinin, pertactin, and fimbriae type 1 and type 2. Although studies of adults who have been vaccinated with acellular pertussis vaccines have had shorter follow-up periods than studies of adults with pertussis infection, the antibody decay patterns are similar in both group
Infrared studies of impurity states and ultrafast carrier dynamics in semiconductor quantum structures
This thesis deals with infrared studies of impurity states, ultrafast carrier dynamics as well as coherent intersubband polarizations in semiconductor quantum structures such as quantum wells and superlattices, based on the GaAs/AlGaAs material system. In the first part it is shown that the 2pz confined impurity state of a semiconductor quantum well develops into an excited impurity band in the case of a superlattice. This is studied by following theoretically the transition from a single to a multiple quantum well or superlattice by exactly diagonalizing the three-dimensional Hamiltonian for a quantum well system with random impurities. Intersubband absorption experiments, which can be nearly perfectly reproduced by the theory, corroborate this interpretation, showing that at low temperatures in the low doping density regime all optical transitions originate from impurity transitions. These results also require reinterpretation of previous experimental data. The relaxation dynamics of interminiband transitions in doped GaAs/AlGaAs superlattices in the mid-IR are studied. This involves single-color pump-probe measurements to explore the dynamics at different wavelengths, which is performed with the Rossendorf freeelectron laser (FEL), providing picosecond pulses in a range from 3-200 Āµm and are used for the first time within this thesis. In these experiments, a fast bleaching of the interminiband transition is observed followed by thermalization and subsequent relaxation, whose time constants are determined to be 1-2 picoseconds. This is followed by an additional component due to carrier cooling in the lower miniband. In the second part, two-color pump-probe measurements are performed, involving the FEL as the pump source and a table-top broad-band tunable THz source for probing the transmission changes. These measurements allow a separate specification of the cooling times after a strong excitation, exhibiting time constants from 230 ps to 3 ps for different excitation densities and miniband widths. In addition, the dynamics of excited electrons within the minibands is explored and their contribution quantitatively extracted from the measurements. Intersubband absorption experiments of photoexcited carriers in single quantum well structures, measured directly in the time-domain, i.e. probing coherently the polarization between the first and the second subband, are presented. From the data we can directly extract the density and temperature dependence of the intersubband dephasing time between the two lowest subbands, ranging from 50 up to 400 fs. This all optical approach gives us the ability to tune the carrier concentration over an extremely wide range which is not accessible in a doped quantum well sample. By varying the carrier density, many-body effects such as the depolarization and their influence on the spectral position as well as on the lineshape on the intersubband dephasing are studied. Also the difference of excitonic and free-carrier type excitation is discussed, and indication of an excitonic intersubband transition is found
Northwest Tribal Registry--Seattle Indian Health Board Record Linkage Project.
In the last ten years several reports using a variety of health data sets have shown a high proportion of racial misclassification for Northwest American Indians and Alaskan Natives (AI/ANs). The result of this has been an underestimation of the burden of various diseases among Northwest AI/ANs. To address health issues related to misclassification, the Northwest Tribal Epidemiology Center has developed the Northwest Tribal Registry (NTR), which contains a demographic data set of 135,060 Northwest AI/ANs, and which can be used for record linkage studies to ascertain accurate disease rates for Northwest AI/ANs. However, the Seattle Indian Health Board Registration contains a large number of Northwest AI/ANs, and it has not yet been incorporated into the NTR. To ascertain the degree of concordance between the NTR and SIHB Registration, we conducted a record linkage study linking these two files. RESULTS: Of the 23,337 entries in the SIHB Registration, only 7,005 (30%) linked or matched with the NTR, leaving 16,332 who were not matched. Among the SIHB-NTR matches, 1,597 (22.8%) were from Northwest tribes; among the SIHB-NTR non-matches, only 3,413 (20.9%) were from Northwest tribes. CONCLUSION: The NTR is missing information on a substantial number of AI/ANs who have utilized the Seattle Indian Health Board for health care services. However, less than a fourth of these individuals are from Northwest tribes served by the Northwest Portland Area Indian Health Board
Metabolite analysis of Mycobacterium species under aerobic and hypoxic conditions reveals common metabolic traits
Re-Inventing Public Education:The New Role of Knowledge in Education Policy-Making
This article focuses on the changing role of knowledge in education policy making within the knowledge society. Through an examination of key policy texts, the Scottish case of Integrated Children Services provision is used to exemplify this new trend. We discuss the ways in which knowledge is being used in order to re-configure education as part of a range of public services designed to meet individuals' needs. This, we argue, has led to a 'scientization' of education governance where it is only knowledge, closely intertwined with action (expressed as 'measures') that can reveal problems and shape solutions. The article concludes by highlighting the key role of knowledge policy and governance in orienting education policy making through a re-invention of the public role of education
Electron paramagnetic resonance and photo-electron paramagnetic resonance investigation on the recharging of the substitutional nitrogen acceptor in ZnO
Against politicization of science: Comment on S. Keller: Scientization: putting global climate change on the scientific agenda since 1970 and the role of the IPCC
Fiscal and Policy Implications of Selling Pipe Tobacco for Roll-Your-Own Cigarettes in the United States
The Federal excise tax was increased for tobacco products on April 1, 2009. While excise tax rates prior to the increase were the same for roll-your-own (RYO) and pipe tobacco, the tax on pipe tobacco was 1.3 billion.Marketing pipe tobacco as ādual purpose" and selling it for RYO use provides an opportunity to avoid paying higher cigarette prices. This blunts the public health impact excise tax increases would otherwise have on reducing tobacco use through higher prices. Selling pipe tobacco for RYO use decreases state and Federal revenue and also avoids regulations on flavored tobacco, banned descriptors, prohibitions on shipping, and reporting requirements
Clinical Definitions of Pertussis: Summary of a Global Pertussis Initiative Roundtable Meeting, February 2011
Existing clinical case definitions of pertussis are decades old and based largely on clinical presentation in infants and children, yet an increasing burden is borne by adolescents and adults who may manifest distinct signs/symptoms. Therefore, a āone-size-fits-allā clinical case definition is no longer appropriate. Seeking to improve pertussis diagnosis, the Global Pertussis Initiative (GPI) developed an algorithm that delineates the signs/symptoms of pertussis most common to 3 age groups: 0ā3 months, 4 months to 9 years, and ā„10 years. These case definitions are based on clinical presentation alone, but do include recommendations on laboratory diagnostics. Until pertussis can be accurately diagnosed, its burden will remain underestimated, making the introduction of epidemiologically appropriate preventive strategies difficult. The proposed definitions are intended to be widely applicable and to encourage the expanded use of laboratory diagnostics. Determination of their utility and their sensitivity and/or specificity versus existing case definitions is required
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