915 research outputs found
Alteration of host cell ubiquitination by the intracellular bacterial pathogen Coxiella burnetii
The intracellular bacterial agent of Q fever, Coxiella burnetii, replicates within a phagolysosomelike parasitophorous vacuole (PV) in human macrophages and delivers effector proteins to the host cytosol via a Dot/Icm type IV secretion system (T4SS). The T4SS effectors are critical for PV formation and prevention of host cell death that allows sufficient time for bacterial replication. Recruitment of ubiquitin-related components to the C. burnetii PV is also predicted to be involved in PV formation and bacterial replication and is likely controlled by effector proteins. In this study, we assessed the role of the Dot/Icm T4SS in regulating ubiquitination by comparing subcellular localization of ubiquitinated proteins between cells infected with C. burnetii and a mutant that lacks a functional T4SS. Fluorescence microscopy showed ubiquitinated proteins surrounding wild-type C. burnetii PV but not phagosomes harboring T4SS-defective organisms. Immunoblot analysis showed altered ubiquitinated protein profiles throughout infection, suggesting C. burnetii impacts post-translational modification of host cell and/or bacterial proteins. Future studies will determine how T4SS-mediated recruitment of ubiquitinated proteins impacts C. burnetii-host cell interactions and eventual development of diseas
Experimental Lagrangian Acceleration Probability Density Function Measurement
We report experimental results on the acceleration component probability
distribution function at to probabilities of less than
. This is an improvement of more than an order of magnitude over past
measurements and allows us to conclude that the fourth moment converges and the
flatness is approximately 55. We compare our probability distribution to those
predicted by several models inspired by non-extensive statistical mechanics. We
also look at acceleration component probability distributions conditioned on a
velocity component for conditioning velocities as high as 3 times the standard
deviation and find them to be highly non-Gaussian.Comment: submitted for the special issue of Physica D: "Anomalous
Distributions" 11 pages, 6 figures revised version: light modifications of
the figures and the tex
Self-Perceived Health and Outlook Among the Rural Elderly
Differences in life outlook and self-perceived health often attributed to age differences among the elderly were found to be more accurately explained by education. The young-old (62-74 years) and the old-old (75 years and older) were compared among 495 elderly in two rural counties in western Arkansas. The old-old were more likely than the young-old to perceive their health as better than that of others their age. But when six variables including age were entered into a predictive model for self-perceived health, differences were explained by education. That is, those with better educations rated their health more positively. There was no difference between the two age groups in sick days, although the old-old reported more days hospitalized and trips to the doctor. However, no predictive model for health status measured was statistically significant. On measures of life satisfaction, the old-old were slightly more pessimistic than the young-old. But the age difference in life outlook was explained by education when the data were controlled for other variables. The customary division of the elderly into young-old and old-old is questioned, and policy implications of the findings are discussed
An Overview of International Development Perspectives in History: Focus on Agricultural and Rural Development
This essay has developed gradually over the approximately 20 years, until 2000, that I taught what was then listed as AGEC 5163 and RSOC 5163, International Agricultural and Rural Development. The first draft was written during the "New Directions" mandate period, while the Green Revolution and its Agricultural Fundamentalism dominated and the Washington Consensus strategy was just emerging. Project funding was still common in international agricultural development, at least in USDA. A dramatic shift from the biological science research of the Green Revolution to Farming Systems Research was underway. The UoA Division of Agriculture had just obtained $5.0 million "Strengthening" grant from USAID, and had successfully competed for several large agricultural development contracts; in Egypt, Haiti, Rwanda, and Burundi. Major updates were prepared in 2000, and again in the summer of 2004.Community/Rural/Urban Development, International Development,
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LENSÂź and SFF: Enabling Technologies for Optimized Structures
Optimized, lightweight, high-strength structures are needed in many applications from aerospace
to automotive. In pursuit of such structures, there have been proposed analytical solutions and
some specialized FEA solutions for specific structures such as automobile frames. However,
generalized 3D optimization methods have been unavailable for use by most designers.
Moreover, in the cases where optimized structural solutions are available, they are often hollow,
curving, thin wall structures that cannot be fabricated by conventional manufacturing methods.
Researchers at Sandia National Laboratories and the University of Rhode Island teamed to solve
these problems. The team has been pursuing two methods of optimizing models for generalized
loading conditions, and also has been investigating the methods needed to fabricate these
structures using Laser Engineered Net Shapingâą (LENSÂź) and other rapid prototyping
methods. These solid freeform fabrication (SFF) methods offer the unique ability to make
hollow, high aspect ratio features out of many materials. The manufacturing development
required for LENS to make these complex structures has included the addition of rotational axes
to Sandiaâs LENS machine bringing the total to 5 controlled axes. The additional axes have
required new efforts in process planning. Several of the unique structures that are only now
possible through the use of SFF technology are shown as part of the discussion of this exciting
new application for SFF.Mechanical Engineerin
Effects of non-universal large scales on conditional structure functions in turbulence
We report measurements of conditional Eulerian and Lagrangian structure
functions in order to assess the effects of non-universal properties of the
large scales on the small scales in turbulence. We study a 1m 1m
1.5m flow between oscillating grids which produces
while containing regions of nearly homogeneous and highly inhomogeneous
turbulence. Large data sets of three-dimensional tracer particle velocities
have been collected using stereoscopic high speed cameras with real-time image
compression technology. Eulerian and Lagrangian structure functions are
measured in both homogeneous and inhomogeneous regions of the flow. We
condition the structure functions on the instantaneous large scale velocity or
on the grid phase. At all scales, the structure functions depend strongly on
the large scale velocity, but are independent of the grid phase. We see clear
signatures of inhomogeneity near the oscillating grids, but even in the
homogeneous region in the center we see a surprisingly strong dependence on the
large scale velocity that remains at all scales. Previous work has shown that
similar correlations extend to very high Reynolds numbers. Comprehensive
measurements of these effects in a laboratory flow provide a powerful tool for
assessing the effects of shear, inhomogeneity and intermittency of the large
scales on the small scales in turbulence
Measuring Multidimensional Poverty in a Complex Environment; Identifying the Sensitive Links
The central hypothesis of this study is that a holistic, systems-based approach employing multiple analytical tools is useful for identifying the most sensitive links within complex communities to down-scale global development priorities such as the United Nations Sustainable Development Goals. Results of latent factor regression, canonical correlation analysis, and structural equation modeling were compared for multiple, publically-available data sets for two rural regions in Brazil and Guatemala. The results of this study confirm previously reported findings, and collectively support the central hypothesis demonstrating a pathway for linking global priorities with the complex realities of \u27on-the-ground\u27 development conditions in specific communities
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