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Adaptive routing in active networks
New conceptual ideas on network architectures have been proposed in the recent past. Current store-andforward
routers are replaced by active intermediate systems,
which are able to perform computations on transient packets,
in a way that results very helpful for developing and
deploying new protocols in a short time. This paper introduces a new routing algorithm, based on a congestion
metric, and inspired by the behavior of ants in nature. The
use of the Active Networks paradigm associated with a cooperative learning environment produces a robust, decentralized algorithm capable of adapting quickly to changing conditions
A roadmap for Feynman's adventures in the land of gravitation
Feynman's multifaceted contributions to gravitation, as can be inferred from
several published and unpublished sources, are here reviewed. Feynman thought
about this subject at least from late 1954 to the late '60s, giving several
contributions to it. Even if he only published three papers on gravity, much
more material is available, especially the records of his many interventions at
the Chapel Hill conference in 1957, which are here analyzed in detail. There,
Feynman showed that he had already developed much of his picture of gravity,
and he expressed deep thoughts about fundamental issues in quantum mechanics,
such as superpositions of the wave functions of macroscopic objects and the
role of the observer, which were suggested by the problem of quantum gravity.
Moreover, Feynman lectured on gravity several times. Besides the famous
lectures given at Caltech in 1962-63, he extensively discussed this subject in
a series of lectures given at the Hughes Aircraft Company in 1966-67, whose
focus was astronomy and astrophysics. Here Feynman gave a somewhat simplified
exposition with respect to the Caltech lectures, but with many original points.
All this material allows to reconstruct a detailed picture of Feynman's ideas
on gravity and of its evolution until the late sixties. The main points are
that gravity, like electromagnetism, has a quantum foundation, so that
classical general relativity has to be regarded as emerging from an underlying
quantum theory, and that this quantum theory has to be investigated by
computing physical processes, as if they were measurable. The same attitude is
shown with respect to gravitational waves, as evident both from the Chapel Hill
records and a letter written to V. Weisskopf. As a bonus, an original approach
to gravity, which closely mimics the derivation of the Maxwell equations he
gave in that period, is hinted at in the unpublished lectures.Comment: 35 pages, no figures, submittet for publicatio
When physics meets biology: a less known Feynman
We discuss a less known aspect of Feynman's multifaceted scientific work,
centered about his interest in molecular biology, which came out around 1959
and lasted for several years. After a quick historical reconstruction about the
birth of molecular biology, we focus on Feynman's work on genetics with Robert
S. Edgar in the laboratory of Max Delbruck, which was later quoted by Francis
Crick and others in relevant papers, as well as in Feynman's lectures given at
the Hughes Aircraft Company on biology, organic chemistry and microbiology,
whose notes taken by the attendee John Neer are available. An intriguing
perspective comes out about one of the most interesting scientists of the XX
century.Comment: On the centenary of the birth of Richard P. Feynman (May 11, 1918 -
February 15, 1988
Sistemi di visione 2D per micromanipolazione automatizzata: metodi di classificazione di componenti
Ef3S: An evaluation framework for flash-based systems
NAND Flash memories are gaining popularity in the development of electronic embedded systems for both consumer and mission-critical applications. NAND Flashes crucially influence computing systems development and performances. EF3S, a framework to easily assess NAND Flash based memory systems performances (reliability, throughput, power), is presented. The framework is based on a simulation engine and a running environment which enable developers to assess any application impact. Experimental results show functionality of the framework, analysing several performance-reliability tradeoffs of an illustrative syste
Serum Cystatin C for the diagnosis of acute Kidney Injury in Patients Admitted in the Emergency Department
BACKGROUND: Early diagnosis of acute kidney injury (AKI) at emergency department (ED) is a challenging issue. Current diagnostic criteria for AKI poorly recognize early renal dysfunction and may cause delayed diagnosis. We evaluated the use of serum cystatin C (CysC) for the early and accurate diagnosis of AKI in patients hospitalized from the ED.
METHODS: In a total of 198 patients (105 males and 93 females), serum CysC, serum creatinine (sCr), and estimated glomerular filtration rate (eGFR) were calculated at 0, 6, 12, 24, 48, and 72 hours after presentation to the ED. We compared two groups according to the presence or absence of AKI.
RESULTS: Serial assessment of CysC, sCr, and eGFR was not a strong, reliable tool to distinguish AKI from non-AKI. CysC > 1.44 mg/L at admission, both alone (Odds Ratio = 5.04; 95%CI 2.20-11.52; P < 0.0002) and in combination with sCr and eGFR (Odds Ratio = 5.71; 95%CI 1.86-17.55; P < 0.002), was a strong predictor for the risk of AKI.
CONCLUSIONS: Serial assessment of CysC is not superior to sCr and eGFR in distinguishing AKI from non-AKI. Admission CysC, both alone and in combination with sCr and eGFR, could be considered a powerful tool for the prediction of AKI in ED patients
Geomorphological evolution of western Sicily, Italy
This paper proposes a morphoevolutionary model for western Sicily. Sicily is a chain–foredeep–foreland Âsystem still being built, with tectonic activity involving uplift which tends to create new relief. To reconstruct the Âmorphoevolutionary model, geological, and geomorphological studies were done on the basis of field survey and aerial photographic interpretation. The collected data show large areas characterized by specific geological, geomorphological, and topographical settings with rocks, landforms, and landscapes progressively older from south to north Sicily. The achieved results display: (1) gradual emersion of new areas due to uplift, its interaction with the Quaternary Âglacio-eustatic oscillations of the sea level, and the following production of a flight of stair-steps of uplifted marine Âterraces in southern Sicily, which migrates progressively upward and inwards; in response to the uplift (2) triggering of down-cutting processes that gradually dismantle the oldest terraces; (3) competition between uplift and down-cutting processes, which is responsible for the genesis of river valleys and isolated rounded hills in central Sicily; (4) continuous deepening over time that results in the exhumation of older and more resistant rocks in northern Sicily, where the higher heights of Sicily are realized and the older forms are retained; (5) extensional tectonic event in the northern end of Sicily, that produces the collapse of large blocks drowned in the Tyrrhenian Sea and sealed by coastal-marine deposits during the Calabrian stage; (6) trigger of uplift again in the previously subsiding blocks and its interaction with coastal processes and sea level fluctuations, which produce successions of marine terraces during the Middle–Upper Pleistocene stages
Serum thyroid hormone antibodies are frequent in patients with polyglandular autoimmune syndrome type 3, particularly in those who require thyroxine treatment
Polyglandular autoimmune syndrome (PAS) type 3 consists of autoimmune thyroid
disease (AITD) coexisting with ≥1 non-thyroidal autoimmune disease (NTAID) other
than Addison’s disease and hypoparathyroidism. We evaluated the prevalence and
repertoire of thyroid hormones antibodies (THAb) in PAS-3 patients. Using a radioimmunoprecipation technique, we measured THAb (T3IgM, T3IgG, T4IgM, and T4IgG) in
107 PAS-3 patients and 88 controls (patients with AITD without any NTAID). Based
on the selective coexistence of AITD with one NTAID (chronic autoimmune gastritis,
non-segmental vitiligo or celiac disease), patients were divided into group 1 (chronic
autoimmune gastritis positive, n = 64), group 2 (non-segmental vitiligo positive, n = 24),
and group 3 (celiac disease positive, n = 15). At least one of the four THAb was detected
in 45 PAS-3 patients (42.1%) and 28 controls (31.8%, P = 0.14), with similar rates
in the three PAS-3 groups. The rates of T3Ab, T4Ab, and T3 + T4Ab were similar in
groups 1 and 2, while in group 3, T3Ab was undetected (P = 0.02). In PAS-3 patients,
the rate of levothyroxine treatment was greater in THAb-positive patients compared to
THAb-negative patients (76.7 vs. 56.1%, P = 0.03, RR = 1.4, 95% CI 1.03–1.81). Not
unexpectedly, levothyroxine daily dose was significantly higher in group 1 and group 3,
namely in patients with gastrointestinal disorders, compared to group 2 (1.9 ± 0.4 and
1.8 ± 0.3 vs. 1.5 ± 0.2 μg/kg body weight, P = 0.0005 and P = 0.004). Almost half of
PAS-3 patients have THAb, whose repertoire is similar if chronic autoimmune gastritis
or celiac disease is present. A prospective study would confirm whether THAb positivity
predicts greater likelihood of requiring levothyroxine treatment
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