100,389 research outputs found
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Pelevin’s Trinity in the novel “t”: author – protagonist – reader
No full textThe article attempts to interpret Pelevin's artistic strategy in the novel "T" by exploring its subject organization and addressing the key problems of the author, the protagonist, and the reader as they are seen by the researcher. The article analyzes the peculiarities of constructing the narrative reality in the novel "T", and goes on to discuss Pelevin's philosophic models of the development of the humankind, and the emergence of his new anthropology
Measuring industry-science links through inventor-author relations: A profiling method
No full textIn this pilot study we examine the performance of text-based profiling in recovering a set of validated inventor-author links. In a first step we match patents and publications solely based on their similarity in content. Next, we compare inventor and author names on the highest ranked matches for the occurrence of name matches. Finally, we compare these candidate matches with the names listed in a validated set of inventor-author names. Our text-based profile methodology performs significantly better than a random matching of patents and publications, suggesting that text-based profiling is a valuable complementary tool to the name searches used in previous studies.innovation; industry-science links; text-based profiling;
Wave turbulence of a rotating array of quantized vortices in the T → 0 temperature limit
No full textThe dynamics of quantized vortices in the zero temperature limit is currently of great interest, particularly in the case of the Fermi superfluid He-B. Here we study wave turbulence, generated by the librating motion of a rotating cylindrical container filled with He-B, in the limit of vanishing viscous forces at temperatures . The polarization of the quantized vortices with respect to the axis of rotation is measured using non-invasive NMR techniques. We observe a decrease of the polarization when the librating motion is started, and a two-stage relaxation process when the modulation of the rotation velocity is stopped. The first relaxation process is associated with the dissipation of large-scale flow stored in inertial waves and the solid body rotation of the vortex array. From the decay of these energy reservoirs we determine the rate of energy dissipation of large-scale flow. The later second process is related to the relaxation of Kelvin waves on individual vortices. This process is monitored by the recovery of the polarization. The existence of a Kelvin wave cascade at the lowest temperatures is currently a central open question. We supply some evidence for the cascade
DNA fusion gene vaccination mobilizes effective anti-leukemic cytotoxic T lymphocytes from a tolerized repertoire
No full textThe majority of known human tumor-associated antigens derive from non-mutated self proteins. T cell tolerance, essential to prevent autoimmunity, must therefore be cautiously circumvented to generate cytotoxic T cell responses against these targets. Our strategy uses DNA fusion vaccines to activate high levels of peptide-specific CTL. Key foreign sequences from tetanus toxin activate tolerance-breaking CD4+ T cell help. Candidate MHC class Ibinding tumor peptide sequences are fused to the C terminus for optimal processing and presentation. To model performance against a leukemia-associated antigen in a tolerized setting, we constructed a fusion vaccine encoding an immunodominant CTL epitopederived from Friend murine leukemia virus gag protein (FMuLVgag) and vaccinated tolerant FMuLVgag-transgenic (gag-Tg) mice. Vaccination with the construct induced epitopespecificIFN-c-producing CD8+ T cells in normal and gag-Tg mice. The frequency and avidity of activated cells were reduced in gag-Tg mice, and no autoimmune injury resulted. However, these CD8+ T cells did exhibit gag-specific cytotoxicity in vitro and in vivo. Also, epitope-specific CTL killed FBL-3 leukemia cells expressing endogenous FMuLVgag antigen and protected against leukemia challenge in vivo. These results demonstrate a simple strategy to engage anti-microbial T cell help to activate epitope-specific polyclonal CD8+ T cell responses from a residual tolerized repertoire
Artificial groundwater recharge in forests : soil fauna and microbiology
No full textAt present, approximately half of the drinking water for the city of Basel (Switzerland) is obtained by an artificial groundwater recharge system in a former floodplain area called “Lange Erlen”. Generally, the use of groundwater for drinking water production may lower groundwater tables. Artificial groundwater recharge is a practice of directing and simultaneously purifying water into aquifers, thereby raising the groundwater table and guaranteeing sufficient drinking water sources. Water purification through artificial groundwater recharge is widespread. However, it more commonly involves areas without vegetation, i.e. slow sand filters, dunes or channels and is combined with long flooding periods. In contrast, at the “Lange Erlen”, forested areas are periodically flooded (max. 10 days) with water from the river Rhine. This routine is interrupted by longer regeneration periods. To date, water infiltration and purification processes have remained constant and satisfactory since the system has been established almost 100 years ago. However, detailed knowledge on the belowground processes that have been sustaining the water purification capacity of “Lange Erlen” is scarce.
Intensive flooding may detrimentally affect earthworm populations and result in clogging of the topsoil, which is a common problem in groundwater recharge systems. Earthworms are known to influence water infiltration and aeration of soils, but most of the existing knowledge relates to grasslands and little is known about the role of earthworms for water infiltration in forests. To better understand the “Lange Erlen” system in the shallow soil layer, earthworm populations, microbial parameters (substrate induced respiration, SIR) and water infiltration rates were studied at the recharge areas. The findings suggest that earthworms are an important factor of the long-term sustainability of this system (for the past ~100 years). The total earthworm
numbers and biomass in watered sites exceeded those of non-watered sites (+51% and +71%, respectively). Total earthworm numbers, numbers of endogeic (mineral forms) and epigeic (litter dwellers) earthworms, and numbers of two species (Lumbricus rubellus and Allolobophora chlorotica) significantly and positively correlated with water infiltration rates. Microbial biomass and activity was significantly enhanced in the top soil layer of the watered sites. The results imply that the flooding regime at the “Lange Erlen” favors earthworm populations which in turn prevent soil clogging, aerate the top soil layer, and stimulate microbial growth.
Groundwater quality is directly influenced by subsurface microbial, chemical and physical soil processes. However, most studies on microbial communities have been limited to the top soil layer. These studies disregarded deeper soil horizons although subsurface microorganisms are crucial for the degradation of natural organic compounds or contaminants and the maintenance of groundwater quality. Therefore, vertical soil profiles down to approximately 4 m of depth from two watered sites and one non-watered site were investigated for the structural (phospholipid fatty acids, PLFAs) and the functional (extracellular hydrolytic enzymes) microbial community composition. Furthermore, additional microbial (by SIR), physical and chemical soil parameters were obtained from the same soil samples.
The microbial biomass did not differ between watered sites and the non-watered site, however considerable fractions of the microbial biomass (25-42% by PLFA and 42-58% by SIR) were located in 40-340 cm depth at all sites. The microbial activity (CO2 emission) and the specific respiration (qCO2) were highest at the watered sites. The microbial community structure differed significantly between watered and non-watered sites (predominantly below 100 cm depth), whereas the functional structure (based on the relative enzyme pattern) differed significantly between all sites. The latter finding could probably be explained by different soil structures in each soil
profile rather than by flooding. Proportions of the bacterial PLFAs 16:1ω5, 16:1ω7, cy17:0 and 18:1ω9t, and the long chained PLFAs 22:1ω9 and 24:1ω9 were more prominent at the watered sites, whereas branched, saturated PLFAs (iso/anteiso) dominated at the non-watered site. The PLFA community indices indicated stress response and higher nutrient availability due to flooding. The analysis of extracellular soil enzymes revealed that acid phosphatase showed highest absolute activities at all field sites throughout the soil depth transect and was followed by L-leucine aminopeptidase and β-glucosidase. Combining the structural and the functional diversity of the microbial community in one analysis revealed significant correlations between the PLFA pattern and specific enzymes activities in the non-watered site. However, at the watered sites these relationships were not detected and the same factors appeared uncoupled from each other.
Overall, this implies that adding labile nutrients (i.e. DOC or DON by flooding) to a soil where other nutrients are limiting microbial growth (i.e. P as indicated by acid phosphatase) increases microbial activity but not biomass. This in turn results in waste respiration by overflow metabolism. Additionally, slight nutrient leaching (e.g. nitrate) into the groundwater is observed due to P-limiting conditions.
No differences in absolute and specific enzyme activities between watered sites and the non-watered site indicated complex organic matter input at the recharge sites to be impeded by flooding water pretreatment. In conclusion, water recharge processes resulted in a microbial community adapted to resource and environmental conditions, which was predominantly located in the upper (100-220 cm depth) and partly in the lower vadose zone (220-280 cm depth). Given a better understanding, the system may be more widely adopted and used to provide sufficient and reliable drinking water to the city of Basel
Acoustic radiation due to scattering of T-S wave by the mean-flow distortion induced by steady local suction
No full textSubstantial sound waves can be generated by boundary-layer instability modes when the latter are scattered by a rapid mean-flow distortion. This is a rather generic mechanism and operates when an oncoming T-S wave is scattered by a steady local suction slot. This paper focuses on this problem by extending a recently developed Local Scattering Theory (Wu & Dong, J. Fluid Mech. submitted), where a so-called transmission coefficient, defined as the ratio of the T-S wave amplitude downstream of the scatter to that upstream, is introduced to characterize the effect of a local scatter on boundary-layer instability and transition. As in the earlier work, the mathematical formulation is based on triple-deck formulism, but in order to accommodate the acoustic far field, which was not considered in the paper mentioned, the unsteady terms in the upper deck, which play a leading-order role in radiation, are retained, and the influence of the radiated sound on the near-wall perturbation is included. The upper deck equation for the pressure is the Helmholtz equation rather than the Laplace equation. This leads to a modified pressure-displacement relation, which is coupled with the linearized boundary-layer equations in the lower deck. Discretization of the whole system formulates a generalized eigenvalue problem, which is solved numerically. It is found that suction suppresses oncoming T-S waves, and this effect increases with the suction velocity and the slot width. The directivity is ndependent of the flow parameters only when the Mach number is low. The intensity of the radiated sound in general increases with the frequency, the suction velocity and the width of the suction slot. Interestingly, for O(1) suction velocities, the radiated sound is very weak, indicating that the gain of stabilizing effect does not cause aeroacoustic penalty
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