6,836 research outputs found
Helicopter gust response characteristics including unsteady aerodynamic stall effects
The results of an analytical study to evaluate the general response characteristics of a helicopter subjected to various types of discrete gust encounters are presented. The analysis employed was a nonlinear coupled, multi-blade rotorfuselage analysis including the effects of blade flexibility and unsteady aerodynamic stall. Only the controls-fixed response of the basic aircraft without any aircraft stability augmentation was considered. A discussion of the basic differences between gust sensitivity of fixed and rotary wing aircraft is presented. The effects of several rotor configuration and aircraft operating parameters on initial gust-induced load factor and blade vibratory stress and pushrod loads are discussed
Impact of Sodium Layer variations on the performance of the E-ELT MCAO module
Multi-Conjugate Adaptive Optics systems based on sodium Laser Guide Stars may
exploit Natural Guide Stars to solve intrinsic limitations of artificial
beacons (tip-tilt indetermination and anisoplanatism) and to mitigate the
impact of the sodium layer structure and variability. The sodium layer may also
have transverse structures leading to differential effects among Laser Guide
Stars. Starting from the analysis of the input perturbations related to the
Sodium Layer variability, modeled directly on measured sodium layer profiles,
we analyze, through a simplified end-to-end simulation code, the impact of the
low/medium orders induced on global performance of the European Extremely Large
Telescope Multi-Conjugate Adaptive Optics module MAORY.Comment: 7 pages, 5 figures, SPIE conference Proceedin
Culture and Community Interactions: Essentials for understanding in a globalised world
"Introduction to the issue
Alignment and preliminary outcomes of an ELT-size instrument to a very large telescope: LINC-NIRVANA at LBT
LINC-NIRVANA (LN) is a high resolution, near infrared imager that uses a
multiple field-of-view, layer-oriented, multi-conjugate AO system, consisting
of four multi-pyramid wavefront sensors (two for each arm of the Large
Binocular Telescope, each conjugated to a different altitude). The system
employs up to 40 star probes, looking at up to 20 natural guide stars
simultaneously. Its final goal is to perform Fizeau interferometric imaging,
thereby achieving ELT-like spatial resolution (22.8 m baseline resolution). For
this reason, LN is also equipped with a fringe tracker, a beam combiner and a
NIR science camera, for a total of more than 250 optical components and an
overall size of approximately 6x4x4.5 meters. This paper describes the
tradeoffs evaluated in order to achieve the alignment of the system to the
telescope. We note that LN is comparable in size to planned ELT
instrumentation. The impact of such alignment strategies will be compared and
the selected procedure, where the LBT telescope is, in fact, aligned to the
instrument, will be described. Furthermore, results coming from early
night-time commissioning of the system will be presented.Comment: 8 pages, 6 pages, AO4ELT5 Proceedings, 201
The jet of the BL Lac object PKS 0521 -365 in the near-IR : MAD adaptive optics observations
BL Lac objects are low--power active nuclei exhibiting a variety of peculiar
properties that are caused by the presence of a relativistic jet and
orientation effects.
We present here adaptive optics near-IR images at high spatial resolution of
the nearby BL Lac object PKS 0521-365, which is known to display a prominent
jet both at radio and optical frequencies. The observations were obtained in
Ks--band using the ESO multi-conjugated adaptive optics demonstrator at the
Very Large Telescope. This allowed us to obtain images with 0.1 arcsec
effective resolution. We performed a detailed analysis of the jet and its
related features from the near-IR images, and combined them with images
previously obtained with HST in the R band and by a re-analysis of VLA radio
maps. We find a remarkable similarity in the structure of the jet at radio,
near-IR, and optical wavelengths. The broad--band emission of the jet knots is
dominated by synchrotron radiation, while the nucleus also exhibits a
significant inverse Compton component. We discovered the near-IR counterpart of
the radio hotspot and found that the near-IR flux is consistent with being a
synchrotron emission from radio to X-ray. The bright red object (red-tip),
detached but well aligned with the jet, is well resolved in the near-IR and has
a linear light profile. Since it has no radio counterpart, we propose that it
is a background galaxy not associated with the jet. The new adaptive optics
near-IR images and previous observations at other frequencies allow us to study
the complex environment around the remarkable BL Lac object PKS 0521-365. These
data exemplify the capabilities of multi conjugate adaptive optics observations
of extragalactic extended sources.Comment: accepted for publication in Astronomy and Astrophysics 9 pages. A & A
2009, in pres
Applying Lean to Healthcare Delivery Processes - a Case-based Research
The purpose of this paper is to demonstrate that Lean principles and methodology should be applied on a regular basis to the entire process flow of healthcare delivery systems. With reference to an actual case-based research, this article demonstrates how patient flows can be successfully optimized if Lean is not limited to single processes/contexts only, and it is applied to achieve holistic process improvement of an entire system. The complexity of healthcare delivery systems requires inclusive investigation from various points of view. This is why case-study-based research has been used to investigate dynamic, experiential and complex processes and areas, such as the ones featured by this article. The methodological basis for this research has been a twelve-step optimization approach outlined by the authors during a previous successful Lean programme. This same approach has been applied to optimize patient flows in the emergency departments of four different hospitals in Northern Italy. The research has involved teams composed of medical, nursing, technical and administrative staff. The results outlined in the article suggest that inclusive application of Lean tools leads to effective process optimization and a better working environment, when in connection with a systematic and holistic optimization approach. Feedback from participants was obtained through a satisfaction survey and a project assessment; it reported enthusiastic project acceptance and good teamwork climate. Among the results of the research performed in the four hospitals, several measures have been effectively implemented to reduce the lead-time for patients from registration to discharge. At the same time, patient-staff ratio and quality of care have been either maintained or even improved. However, lack of a definite conclusive evaluation can be explained by the research project still being implemented. The value of this paper lies in demonstrating how Lean contributes to achieve better process performance and high staff satisfaction, when implemented within the whole supply chain of a healthcare delivery system on a regular basis
Insulin Resistance and Cancer Risk: An Overview of the Pathogenetic Mechanisms
Insulin resistance is common in individuals with obesity or type 2 diabetes (T2D), in which circulating insulin levels are frequently increased. Recent epidemiological and clinical evidence points to a link between insulin resistance and cancer. The mechanisms for this association are unknown, but hyperinsulinaemia (a hallmark of insulin resistance) and the increase in bioavailable insulin-like growth factor I (IGF-I) appear to have a role in tumor initiation and progression in insulin-resistant patients. Insulin and IGF-I inhibit the hepatic synthesis of sex-hormone binding globulin (SHBG), whereas both hormones stimulate the ovarian synthesis of sex steroids, whose effects, in breast epithelium and endometrium, can promote cellular proliferation and inhibit apoptosis. Furthermore, an increased risk of cancer among insulin-resistant patients can be due to overproduction of reactive oxygen species (ROS) that can damage DNA contributing to mutagenesis and carcinogenesis. On the other hand, it is possible that the abundance of inflammatory cells in adipose tissue of obese and diabetic patients may promote systemic inflammation which can result in a protumorigenic environment. Here, we summarize recent progress on insulin resistance and cancer, focusing on various implicated mechanisms that have been described recently, and discuss how these mechanisms may contribute to cancer initiation and progression
Genetic variation in insulin‐induced kinase signaling
Individual differences in sensitivity to insulin contribute to disease susceptibility including diabetes and metabolic syndrome. Cellular responses to insulin are well studied. However, which steps in these response pathways differ across individuals remains largely unknown. Such knowledge is needed to guide more precise therapeutic interventions. Here, we studied insulin response and found extensive individual variation in the activation of key signaling factors, including ERK whose induction differs by more than 20‐fold among our subjects. This variation in kinase activity is propagated to differences in downstream gene expression response to insulin. By genetic analysis, we identified cis‐acting DNA variants that influence signaling response, which in turn affects downstream changes in gene expression and cellular phenotypes, such as protein translation and cell proliferation. These findings show that polymorphic differences in signal transduction contribute to individual variation in insulin response, and suggest kinase modulators as promising therapeutics for diseases characterized by insulin resistance.SynopsisGenetic variants contribute to individual variation in insulin response, including kinase activation, changes in gene expression and cell growth, suggesting kinase modulators as promising therapeutics for diseases characterized by insulin resistance.Extensive individual variation is observed in insulin‐induced activation of signal transduction.The variation in signaling response is propagated downstream to influence gene expression and cell growth.There is a genetic component to the individual differences in signaling and gene expression response to insulin.Genetic variants contribute to individual variation in insulin response, including kinase activation, changes in gene expression and cell growth, suggesting kinase modulators as promising therapeutics for diseases characterized by insulin resistance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112224/1/msb156250-sup-0001-EVFigs.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112224/2/msb156250.reviewer_comments.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112224/3/msb156250.pd
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