4,744 research outputs found
Cicrumnuclear Supernova Remnants and HII Regions in NGC 253
Archival VLA data has been used to produce arcsecond-resolution 6- and 20-cm
images of the region surrounding the nuclear 200-pc (~15") starburst in NGC
253. Twenty-two discrete sources stronger than 0.4 mJy have been detected
within ~2 kpc (~3') of the galaxy nucleus; almost all these sources must be
associated with the galaxy. None of the radio sources coincides with a detected
X-ray binary, so they appear to be due to supernova remnants and H II regions.
The region outside the central starburst has a derived radio supernova rate of
<~0.1/yr, and may account for at least 20% of the recent star formation in NGC
253. Most of the newly identified sources have steep, nonthermal radio spectra,
but several relatively strong thermal sources also exist, containing the
equivalent of tens of O5 stars. These stars are spread over tens of parsecs,
and are embedded in regions having average ionized gas densities of
20-200/cm^3, much lower than in the most active nuclear star-forming regions in
NGC 253 or in the super star clusters seen in other galaxies. The strongest
region of thermal emission coincides with a highly reddened area seen at
near-infrared wavelengths, possibly containing optically obscured H II regions.Comment: 17 pages, 3 postscript figures, AASTeX format, in press for
Astronomical Journal, July 200
Probabilistically-robust nonlinear control of offshore structures
A controller design for offshore structures is discussed in this study.
Stochastic simulation is considered for evaluation of the system's
performance in the design stage. This way, nonlinear characteristics of
the structural response and excitation are explicitly incorporated into
the model assumed for the system. Model parameters that have some
level of uncertainty are probabilistically described. In this context, the
controller is designed for optimal reliability, quantified as the
probability, based on the available information, that the performance
will not exceed some acceptable bounds. This treatment leads to a
robust-to-uncertainty design. The methodology is illustrated in an
example involving the control of a Tension Leg Platform in a random
sea environment. Multifold nonlinearities are taken into account for the
evaluation of the platform's dynamic response and a probabilistic
description is adopted for characterizing the random sea environment
Children, family and the state : revisiting public and private realms
The state is often viewed as part of the impersonal public sphere in opposition to the private family as a locus of warmth and intimacy. In recent years this modernist dichotomy has been challenged by theoretical and institutional trends which have altered the relationship between state and family. This paper explores changes to both elements of the dichotomy that challenge this relationship: a more fragmented family structure and more individualised and networked support for children. It will also examine two new elements that further disrupt any clear mapping between state/family and public/private dichotomies: the third party role of the child in family/state affairs and children's application of virtual technology that locates the private within new cultural and social spaces. The paper concludes by examining the rise of the 'individual child' hitherto hidden within the family/state dichotomy and the implications this has for intergenerational relations at personal and institutional levels
Determination of the critical current density in the d-wave superconductor YBCO under applied magnetic fields by nodal tunneling
We have studied nodal tunneling into YBa2Cu3O7-x (YBCO) films under magnetic
fields. The films' orientation was such that the CuO2 planes were perpendicular
to the surface with the a and b axis at 450 form the normal. The magnetic field
was applied parallel to the surface and perpendicular to the CuO2 planes. The
Zero Bias Conductance Peak (ZBCP) characteristic of nodal tunneling splits
under the effect of surface currents produced by the applied fields. Measuring
this splitting under different field conditions, zero field cooled and field
cooled, reveals that these currents have different origins. By comparing the
field cooled ZBCP splitting to that taken in decreasing fields we deduce a
value of the Bean critical current superfluid velocity, and calculate a Bean
critical current density of up to 3*10^7 A/cm2 at low temperatures. This
tunneling method for the determination of critical currents under magnetic
fields has serious advantages over the conventional one, as it avoids having to
make high current contacts to the sample.Comment: 8 pages, 2 figure
Third World gap year projects: Youth transitions and the mediation of risk
This is the post-print version of the final published article. The definitive, peer-reviewed and edited version of this article is available from the link below. Copyright @ 2008 Pion.In recent years in the UK there has been a great expansion in the number of young people travelling to Third World countries between school and university in order to participate as volunteers on structured gap year projects. Travel to such places is commonly perceived as ‘risky’, and takes young people outside the protective cocoon of UK health and safety legislation. One of the functions played by the providers of gap year projects is to mediate risk. On the basis of analysis of promotional literature, interviews with organisers of gap year projects, and focus groups of returned volunteers, in this paper I argue that the various strategies of risk mediation undertaken by gap year providers serve to reconcile modernising tendencies in UK society toward risk control and structure with postmodern inclinations towards individualisation and uncertainty
Vincristine Side Effects with Concomitant Fluconazole Use during Induction Chemotherapy in Pediatric Acute Lymphoblastic Leukemia
As a mainstay of treatment for acute lymphoblastic leukemia (ALL), vincristine’s side effect profile is well known. Parallel administration of the antifungal fluconazole has been shown to interfere with the metabolism of vincristine, potentially resulting in increased side effects. We conducted a retrospective chart review to determine whether concomitant administration of vincristine and fluconazole during pediatric ALL therapy impacted side effects of vincristine, namely, hyponatremia and peripheral neuropathy. We also evaluated whether the incidence of opportunistic fungal infections was impacted by fluconazole prophylaxis. Medical charts of all pediatric ALL patients treated with induction chemotherapy at Children’s Hospital and Medical Center in Omaha, NE from 2013-2021 were retrospectively reviewed. We found no correlation between fluconazole use and increased incidence of peripheral neuropathy or hyponatremia. Additionally, the rate of fungal infections was not impacted by fluconazole prophylaxis. Empiric fungal prophylaxis with fluconazole during pediatric ALL induction, although safe, may not be necessary.https://digitalcommons.unmc.edu/chri_forum/1039/thumbnail.jp
Pediatric Acute Lymphoblastic Leukemia Patients and Potential Risk for Vincristine Side Effects with Concomitant Fluconazole
Background: Pediatric Acute Lymphoblastic Leukemia (ALL) patients undergoing intensive treatment are considered at high risk for opportunistic infections. To prevent invasive fungal infection, some patients receive antifungal prophylaxis such as fluconazole. As a consequence, an increase in vincristine toxicity has been associated with the co-administration of antifungal prophylaxis. We analyzed whether the use of fluconazole prophylaxis impacts vincristine’s side effects during induction therapy. Method: We conducted a retrospective chart review of all pediatric (age 0-18 years) patients diagnosed with ALL at Children’s Hospital and Medical Center in Omaha, Nebraska from July 2013-May 2021. Patients were divided into two groups based on whether or not they received fluconazole. Incidence of fungal infection, rate and grade of peripheral neuropathy, and prescription for gabapentin (treatment for peripheral neuropathy) were collected for both groups. Results: We had 157 ALL patients, of which 72 patients received fluconazole, and 85 patients did not receive fluconazole. There was no significant difference between fluconazole use and increased incidence of peripheral neuropathy (p value= 0.28) or incidence of hyponatremia (p value =Conclusion: We did not find a statistically significant difference that the use of concomitant fluconazole with vincristine increased the risk of peripheral neuropathy or hyponatremia.https://digitalcommons.unmc.edu/surp2021/1037/thumbnail.jp
TGF-β Suppresses β-Catenin-Dependent Tolerogenic Activation Program in Dendritic Cells
The mechanisms that underlie the critical dendritic cell (DC) function in
maintainance of peripheral immune tolerance are incompletely understood,
although the β-catenin signaling pathway is critical for this role. The
molecular details by which β-catenin signaling is regulated in DCs are
unknown. Mechanical disruption of murine bone marrow-derived DC (BMDC) clusters
activates DCs while maintaining their tolerogenic potential and this activation
is associated with β-catenin signaling, providing a useful model with which
to explore tolerance-associated β-catenin signaling in DCs. In this report,
we demonstrate novel molecular features of the signaling events that control DC
activation in response to mechanical stimulation. Non-canonical β-catenin
signaling is an essential component of this tolerogenic activation and is
modulated by adhesion molecules, including integrins. This unique
β-catenin-dependent signaling pathway is constitutively active at low
levels, suggesting that mechanical stimulation is not necessarily required for
induction of this unique activation program. We additionally find that the
immunomodulatory cytokine TGF-β antagonizes β-catenin in DCs, thereby
selectively suppressing signaling associated with tolerogenic DC activation
while having no impact on LPS-induced, β-catenin-independent immunogenic
activation. These findings provide new molecular insight into the regulation of
a critical signaling pathway for DC function in peripheral immune tolerance
PEER Testbed Study on a Laboratory Building: Exercising Seismic Performance Assessment
From 2002 to 2004 (years five and six of a ten-year funding cycle), the PEER Center organized
the majority of its research around six testbeds. Two buildings and two bridges, a campus, and a
transportation network were selected as case studies to “exercise” the PEER performance-based
earthquake engineering methodology. All projects involved interdisciplinary teams of
researchers, each producing data to be used by other colleagues in their research. The testbeds
demonstrated that it is possible to create the data necessary to populate the PEER performancebased framing equation, linking the hazard analysis, the structural analysis, the development of
damage measures, loss analysis, and decision variables.
This report describes one of the building testbeds—the UC Science Building. The project
was chosen to focus attention on the consequences of losses of laboratory contents, particularly
downtime. The UC Science testbed evaluated the earthquake hazard and the structural
performance of a well-designed recently built reinforced concrete laboratory building using the
OpenSees platform. Researchers conducted shake table tests on samples of critical laboratory
contents in order to develop fragility curves used to analyze the probability of losses based on
equipment failure. The UC Science testbed undertook an extreme case in performance
assessment—linking performance of contents to operational failure. The research shows the
interdependence of building structure, systems, and contents in performance assessment, and
highlights where further research is needed.
The Executive Summary provides a short description of the overall testbed research
program, while the main body of the report includes summary chapters from individual
researchers. More extensive research reports are cited in the reference section of each chapter
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