Derivational morphology in the German mental lexicon: A dual mechanism account

The Dual Mechanism Model posits two different cognitive mechanisms for morphologically complex word forms: decomposition of regulars into stems and exponents, and full-form storage for irregulars. Most of the research in this framework has focused on contrasts between productive and non-productive inflection. In this paper, we extend the model to derivational morphology. Our studies indicate that productive derivation shows affinities with both productive and non-productive inflection. We argue that these results support the linguistic distinction between derivation and inflection, particularly as it is represented in realization-based models of morphology

The informativeness of linguistic unit boundaries

Contemporary models of structural analysis tend to operate with discrete units at different linguistic levels. There is, however, considerable debate regarding the choice of units and the validity of the cues that guide their demarcation. At the level of grammatical analysis, this debate focuses largely on the status of words vs sub-word units and on the generality of the linguistic properties that mark each type of unit. This paper suggests that the status of a unit type can be evaluated in terms of its informativity A measure of informativity is obtained by assessing the influence that different unit boundary types have on text compressibility. The results obtained from this initial study support a pair of general conclusions. The first is that unit boundaries primarily reflect a statistical structure, and that the typological variability of linguistic cues reflects the fact that they serve a secondary reinforcing function. The second is that word boundaries are the most informative boundary type, and that the demarcation of words provides the most informative description of the regular patterns in a language

Spectral geometry, homogeneous spaces, and differential forms with finite Fourier series

Let G be a compact Lie group acting transitively on Riemannian manifolds M and N. Let p be a G equivariant Riemannian submersion from M to N. We show that a smooth differential form on N has finite Fourier series if and only if the pull back has finite Fourier series on

INSPACE CHEMICAL PROPULSION SYSTEMS AT NASA's MARSHALL SPACE FLIGHT CENTER: HERITAGE AND CAPABILITIES

NASA s Marshall Space Flight Center (MSFC) is well known for its contributions to large ascent propulsion systems such as the Saturn V rocket and the Space Shuttle external tank, solid rocket boosters, and main engines. This paper highlights a lesser known but very rich side of MSFC-its heritage in the development of in-space chemical propulsion systems and its current capabilities for spacecraft propulsion system development and chemical propulsion research. The historical narrative describes the flight development activities associated with upper stage main propulsion systems such as the Saturn S-IVB as well as orbital maneuvering and reaction control systems such as the S-IVB auxiliary propulsion system, the Skylab thruster attitude control system, and many more recent activities such as Chandra, the Demonstration of Automated Rendezvous Technology (DART), X-37, the X-38 de-orbit propulsion system, the Interim Control Module, the US Propulsion Module, and multiple technology development activities. This paper also highlights MSFC s advanced chemical propulsion research capabilities, including an overview of the center s Propulsion Systems Department and ongoing activities. The authors highlight near-term and long-term technology challenges to which MSFC research and system development competencies are relevant. This paper concludes by assessing the value of the full range of aforementioned activities, strengths, and capabilities in light of NASA s exploration missions

Increased systemic inflammation is associated with cardiac and vascular dysfunction over the first 12 weeks of antiretroviral therapy among undernourished, HIV-infected adults in Southern Africa.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.INTRODUCTION: Persistent systemic inflammation is associated with mortality among undernourished, HIV-infected adults starting antiretroviral therapy (ART) in sub-Saharan Africa, but the etiology of these deaths is not well understood. We hypothesized that greater systemic inflammation is accompanied by cardiovascular dysfunction over the first 12 weeks of ART. METHODS: In a prospective cohort of 33 undernourished (body mass index <18.5 kg/m2) Zambian adults starting ART, we measured C-reactive protein (CRP), tumor necrosis factor-α receptor 1 (TNF-α R1), and soluble CD163 and CD14 at baseline and 12 weeks. An EndoPAT device measured the reactive hyperemia index (LnRHI; a measure of endothelial responsiveness), peripheral augmentation index (AI; a measure of arterial stiffness), and heart rate variability (HRV; a general marker of autonomic tone and cardiovascular health) at the same time points. We assessed paired changes in inflammation and cardiovascular parameters, and relationships independent of time point (adjusted for age, sex, and CD4+ T-cell count) using linear mixed models. RESULTS: Serum CRP decreased (median change -3.5 mg/l, p=0.02), as did TNF-α R1 (-0.31 ng/ml, p<0.01), over the first 12 weeks of ART. A reduction in TNF-α R1 over 12 weeks was associated with an increase in LnRHI (p=0.03), and a similar inverse relationship was observed for CRP and LnRHI (p=0.07). AI increased in the cohort as a whole over 12 weeks, and a reduction in sCD163 was associated with a rise in the AI score (p=0.04). In the pooled analysis of baseline and 12 week data, high CRP was associated with lower HRV parameters (RMSSD, p=0.01; triangular index, p<0.01), and higher TNF- α R1 accompanied lower HRV (RMSSD, p=0.07; triangular index, p=0.06). CONCLUSIONS: Persistent inflammation was associated with impaired cardiovascular health over the first 12 weeks of HIV treatment among undernourished adults in Africa, suggesting cardiac events may contribute to high mortality in this population.This work was supported by the Vanderbilt Meharry Center for AIDS Research (NIH grant number P30 AI54999); the NIH Fogarty International Center, Office of the Director, National Institutes of Health, National Heart, Blood, and Lung Institute, and National Institute of Mental Health, through the Vanderbilt-Emory-Cornell-Duke Consortium for Global Health Fellows (grant number R25 TW009337); the National Center for Advancing Translational Sciences (CTSA award number UL1TR000445) and the European and Developing Countries Clinical Trials Partnership (grant IP.2009.33011.004)

Design and experimental characterization of a tunable vibration-based electromagnetic micro-generator

Vibration-based micro-generators, as an alternative source of energy, have become increasingly significant in the last decade. This paper presents a new tunable electromagnetic vibration-based micro-generator. Frequency tuning is realized by applying an axial tensile force to the micro-generator. The dimensions of the generator, especially the dimensions of the coil and the air gap between magnets, have been optimized to maximize the output voltage and power of the micro-generator. The resonant frequency has been successfully tuned from 67.6 to 98 Hz when various axial tensile forces were applied to the structure. The generator produced a power of 61.6–156.6 µW over the tuning range when excited at vibrations of 0.59 ms-2. The tuning mechanism has little effect on the total damping. When the tuning force applied on the generator becomes larger than the generator’s inertial force, the total damping increases resulting in reduced output power. The resonant frequency increases less than indicated from simulation and approaches that of a straight tensioned cable when the force associated with the tension in the beam becomes much greater than the beam stiffness. The test results agree with the theoretical analysis presented

Impact of Riparian Grass Filter Strips on Surface-Water Quality

The effectiveness of natural riparian grass filter strips in removing sediment and agricultural chemicals from surface runoff was studied using no-tillage and conventional-tillage erosion plots. Runoff from the tillage plots was directed onto 4.57, 9.14, and 13.72 m (15, 30, and 45 ft.) length filter strips, where the inflow and outflow concentrations and sediment size distributions were measured. Trapping efficiencies for sediment and agricultural chemicals typically ranged near or above 90 percent, mainly because of high infiltration rates. The filters also significantly reduced peak discharge concentrations, which reduced the impact of sediment and agricultural chemicals on receiving surface waters

Water Quality Impacts of Natural Riparian Grasses Part 1: Empirical Studies

Studies were conducted on the effectiveness of natural riparian grass buffer strips in removing sediment and ag chemicals from surface runoff. No till and conventional tillage erosion plots served as the sediment and chemical source area. Runoff from the plots was directed onto 15, 30, and 45 foot filter strips where the inflow and outflow concentrations and sediment size distributions. Trapping percentages for sediment and ag chemicals typically ranged near or above 90%. An evaluation was made of the distribution of trapped chemicals among infiltrated mass and mass stored in the surface layer and on plant surfaces. The analysis showed that most of the chemicals were trapped by infiltration onto the soil matrix

Gender differences in pay levels : an examination of the compensation of university presidents

Our paper studies how gender and organizational status affect a university president’s compensation. Similar to previous findings, we hypothesize that women will receive less pay than men. However, we go beyond a dyadic view of individual differences to examine gender’s impact on compensation, and we explicate the importance of institutional forces in understanding the gender pay gap. In doing so, we rely on organizational status and hypothesize that the gender pay gap will be less pronounced as a university’s status rises. Although we find that the gender pay gap persists within the university president context, we also find that as a university’s status rises, the pay gap declines. Moreover, our findings show that the gender pay gap disappears at higher-status universities. Hence, accounting for where the glass ceiling is broken is an important consideration in understanding the gender pay gap. In sum, by integrating a broader institutional perspective to explain gender differences in pay levels, our paper demonstrates the importance of contextualizing gender to better understand its effects on compensation.https://pubsonline.informs.org/journal/orschj2019Human Resource Managemen

How structural adaptability exists alongside HLA-A2 bias in the human alphabeta TCR repertoire

How T-cell receptors (TCRs) can be intrinsically biased toward MHC proteins while simultaneously display the structural adaptability required to engage diverse ligands remains a controversial puzzle. We addressed this by examining alphabeta TCR sequences and structures for evidence of physicochemical compatibility with MHC proteins. We found that human TCRs are enriched in the capacity to engage a polymorphic, positively charged hot-spot region that is almost exclusive to the alpha1-helix of the common human class I MHC protein, HLA-A*0201 (HLA-A2). TCR binding necessitates hot-spot burial, yielding high energetic penalties that must be offset via complementary electrostatic interactions. Enrichment of negative charges in TCR binding loops, particularly the germ-line loops encoded by the TCR Valpha and Vbeta genes, provides this capacity and is correlated with restricted positioning of TCRs over HLA-A2. Notably, this enrichment is absent from antibody genes. The data suggest a built-in TCR compatibility with HLA-A2 that biases receptors toward, but does not compel, particular binding modes. Our findings provide an instructional example for how structurally pliant MHC biases can be encoded within TCRs