2,422 research outputs found
Non-Lipschitz points and the SBV regularity of the minimum time function
This paper is devoted to the study of the Hausdorff dimension of the singular
set of the minimum time function under controllability conditions which do
not imply the Lipschitz continuity of . We consider first the case of normal
linear control systems with constant coefficients in . We
characterize points around which is not Lipschitz as those which can be
reached from the origin by an optimal trajectory (of the reversed dynamics)
with vanishing minimized Hamiltonian. Linearity permits an explicit
representation of such set, that we call . Furthermore, we show
that is -rectifiable with positive
-measure. Second, we consider a class of control-affine
\textit{planar} nonlinear systems satisfying a second order controllability
condition: we characterize the set in a neighborhood of the
origin in a similar way and prove the -rectifiability of
and that . In both cases, is
known to have epigraph with positive reach, hence to be a locally function
(see \cite{CMW,GK}). Since the Cantor part of must be concentrated in
, our analysis yields that is , i.e., the Cantor part of
vanishes. Our results imply also that is locally of class
outside a -rectifiable set. With small
changes, our results are valid also in the case of multiple control input.Comment: 23 page
Streaming Potential and Electro-osmosis Measurements to Characterize Porous Materials
Characterizing the streaming potential and electroosmosis properties of porous media is essential in applying seismoelectric and electroseismic phenomena for oil exploration. Some parameters such as porosity, permeability, formation factor, pore size, the number of pores, and the zeta potential of the samples can be obtained from elementary measurements. We performed streaming potential and electro-osmosis measurements for 6 unconsolidated samples made of spherical polymer particles. To check the validity of the measurements, we also used alternative analysis to determine the average pore size of the samples and, moreover, used a sample made of sand particles to determine the zeta potential
New records for the liverwort and hornwort flora of Vietnam, 1
After the examination of the Cryptogam collection in the Herbarium of the University of Science, Vietnam National University Ho Chi Minh City (PHH), 25 species proved to be new to Vietnam, including one hornwort and 24 liverworts. Among them, four genera: Denotarisia Grolle, Gongylanthus Nees, Leiomitra Lindb. and Lepicolea Dumort. are new records for the country. Diagnostic characters and illustrations are given for some taxa, as well as locality notes and habitat descriptions are provided for each collecting area
Mere Exposure Effects: Presence of parasitic mites induce a change in the metabolic rate of flies independent of infection
Parasites affect host physiology and populations in numerous ways including: increased mortality, decreased fecundity, and changes to host behavior. Many documented effects depend on infection to explain changes, for example: parasite blood feeding, tissue damage, and costs of immune responses. However, the effects that the mere presence of parasites have on their hosts is relatively unexplored. We study a fruit fly - mite model system. Macrocheles Domesticae is an ectoparasite that reversibly attaches to Drosophila Hydei as a means of transportation as well as feeding on host hemolymph. Since flies must move between resource patches, the effects of parasite infection on flight are significant. This system is can be used to illustrate host-parasite dynamics. We take an ecological physiology perspective and link physical changes in organisms to the larger scale processes of ecology; we deploy respirometry to compare energy consumption of flies under various conditions. Carbon Dioxide produced is measured as a flow, and linked to energy consumption by the cellular respiration equation. We hypothesize that host flight will be impaired by infection. Bioenergetic costs of infection imply this effect will be present even if mites are removed prior to flight. Results show that both flies carrying mites, and flies infected prior to flight, both hover for reduced lengths of time. Additionally, both actively resisting mites, as well as mere exposure to them, increases the Carbon Dioxide output of the host. These results have implications for host fitness and energy budgets in both the evolution and ecology of host-parasite interactions.
*Indicates faculty mento
Multipole Expansion for the Electron-Nucleus Scattering at High Energies in the Unified Electroweak Theory
The article presents the multipole expansion for the electron-nucleus
scattering cross section at high energies within the framework of the unified
electroweak theory. The electroweak currents of the nucleus are expanded into
simple components with definite angular momentum, which are called the
multipole form factors. The multipole expansion of the cross section is a
consequence of the above expansion. Besides the familiar electromagnetic form
factors, there are weak form factors related to weak interactions,
corresponding to the vector and axial (pseudovector) weak currents. We do not
use the impulse approximation, the multipole form factors are calculated
directly, using only the Born approximation. We will present some examples in
the next paper.Comment: 7 pages, 0 figur
Loss of histone macroH2A1 in hepatocellular carcinoma cells promotes paracrine-mediated chemoresistance and CD4+CD25+FoxP3+ regulatory T cells activation
Rationale: Loss of histone macroH2A1 induces appearance of cancer stem cells (CSCs)-like cells in hepatocellular carcinoma (HCC). How CSCs interact with the tumor microenvironment and the adaptive immune system is unclear. Methods: We screened aggressive human HCC for macroH2A1 and CD44 CSC marker expression. We also knocked down (KD) macroH2A1 in HCC cells, and performed integrated transcriptomic and secretomic analyses. Results: Human HCC showed low macroH2A1 and high CD44 expression compared to control tissues. MacroH2A1 KD CSC-like cells transferred paracrinally their chemoresistant properties to parental HCC cells. MacroH2A1 KD conditioned media transcriptionally reprogrammed parental HCC cells activated regulatory CD4+/CD25+/FoxP3+ T cells (Tregs). Conclusions: Loss of macroH2A1 in HCC cells drives cancer stem-cell propagation and evasion from immune surveillance
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Examining causal effects of Emotional Intelligence on human related challenges occurring in Agile managed Information Systems projects
Agile project management has become a widely implemented project management
approach in Information Systems (IS). Yet, along with its growing popularity, the
amount of concerns raised in regard to human related challenges is rapidly
increasing. Nevertheless, the extant scholarly literature has neglected to identify
the primary origins and reasons of these challenges. The purpose of this study is
therefore to examine if these challenges are caused by a lack of Emotional
Intelligence (EI) by means of a quantitative approach, which includes two main
steps. Firstly, based on a sample of 447 IS-professionals, the psychometric
properties of their EI in regard to their personal characteristics is examined.
Secondly, based on the findings of the first analysis, the causal inference of EI on
these challenges is computed using Propensity Score Matching based on a second
sample of 194 agile practitioners. Different dimensions of EI were found to have a
low to medium impact on human related challenges occurring in agile teams in
regard to anxiety, motivation, mutual trust and communication competence. Hence, these findings offer important new knowledge for IS-scholars, project managers
and human resource practitioners, about the vital role of EI for educating, staffing
and training of IS-professionals working in agile teams
Microbial ecology of Thiobacillus ferrooxidans
FINAL TECHNICAL REPORT
TO
U.S. DEPARTMENT OF THE INTERIOR
Geological Survey
Washington. D.C.The contents of this report were developed in part under a grant from
the Department of the Interior, U.S. Geological Survey. Grant number 14-08-0001-61313
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