2,556 research outputs found
Structural development of laminar flow control aircraft chordwise wing joint designs
For laminar flow to be achieved, any protuberances on the surface must be small enough to avoid transition to turbulent flow. However, the surface must have joints between the structural components to allow assembly or replacement of damaged parts, although large continuous surfaces can be utilized to minimize the number the number of joints. Aircraft structural joints usually have many countersunk bolts or rivets on the outer surface. To maintain no mismatch on outer surfaces, it is desirable to attach the components from the inner surface. It is also desirable for the panels to be interchangeable, without the need for shims at the joint, to avoid surface discontinuities that could cause turbulence. Fabricating components while pressing their outer surfaces against an accurate mold helps to ensure surface smoothness and continuity at joints. These items were considered in evaluating the advantages and disadvantages of the joint design concepts. After evaluating six design concepts, two of the leading candidates were fabricated and tested using many small test panels. One joint concept was also built and tested using large panels. The small and large test panel deflections for the leading candidate designs at load factors up to +1.5 g's were well within the step and waviness requirements for avoiding transition.The small panels were designed and tested for compression and tension at -65 F, at ambient conditions, and at 160 F. The small panel results for the three-rib and the sliding-joint concepts indicated that they were both acceptable. The three-rib concept, with tapered splice plates, was considered to be the most practical. A modified three-rib joint that combined the best attributes of previous candidates was designed, developed, and tested. This improved joint met all of the structural strength, surface smoothness, and waviness criteria for laminar flow control (LFC). The design eliminated all disadvantages of the initial three-rib concept except for unavoidable eccentricity, which was reduced and reacted satisfactorily by the rib supports. It should also result in a relatively simple low-cost installation, and makes it easy to replace any panels damaged in the field
Quantum resource estimates for computing elliptic curve discrete logarithms
We give precise quantum resource estimates for Shor's algorithm to compute
discrete logarithms on elliptic curves over prime fields. The estimates are
derived from a simulation of a Toffoli gate network for controlled elliptic
curve point addition, implemented within the framework of the quantum computing
software tool suite LIQ. We determine circuit implementations for
reversible modular arithmetic, including modular addition, multiplication and
inversion, as well as reversible elliptic curve point addition. We conclude
that elliptic curve discrete logarithms on an elliptic curve defined over an
-bit prime field can be computed on a quantum computer with at most qubits using a quantum circuit of at most Toffoli gates. We are able to classically simulate the
Toffoli networks corresponding to the controlled elliptic curve point addition
as the core piece of Shor's algorithm for the NIST standard curves P-192,
P-224, P-256, P-384 and P-521. Our approach allows gate-level comparisons to
recent resource estimates for Shor's factoring algorithm. The results also
support estimates given earlier by Proos and Zalka and indicate that, for
current parameters at comparable classical security levels, the number of
qubits required to tackle elliptic curves is less than for attacking RSA,
suggesting that indeed ECC is an easier target than RSA.Comment: 24 pages, 2 tables, 11 figures. v2: typos fixed and reference added.
ASIACRYPT 201
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Myosin-I nomenclature.
We suggest that the vertebrate myosin-I field adopt a common nomenclature system based on the names adopted by the Human Genome Organization (HUGO). At present, the myosin-I nomenclature is very confusing; not only are several systems in use, but several different genes have been given the same name. Despite their faults, we believe that the names adopted by the HUGO nomenclature group for genome annotation are the best compromise, and we recommend universal adoption
Prospectus, October 24, 1979
SURVEY MAKES WAVES; The Week in Review: Across the globe, In the nation, Throughout the state, Around the town, Etc….; Briefs: College to host math contest, Parkland Players present \u27Dracula\u27, Summary of board listed, Champaign council approves bonds, Women\u27s program seeks young blood, Monticello council to discuss tax rate, Program on strokes to be presented, Arthritis program to be presented, Future educators program tomorrow, Nutritionm health, disease are topics, Store celebrates 1st; Letter to editor: Dean congratulates foreigners; Weekly Calendar; Area high schools to visit campus; S.T.O. raffle winners are announced; Give a little blood, then see blood; Women at Home on Tuesday; Editorial: Censorship at WPCD?; PATH raises grievances; Pumpkins and costumes in contest next week; Lincoln Square has art show; Oktoberfest today: a taste of German; Reviews: Ending to the beat has better taste, B-52s: a glimpse of future and past; Classifieds; Music club has enthusiasm; Athletic and rec fields near completion; V-ball gains momentum; Golf team advances to state; Elam blows off competition: harriers 3rd; PC hosts golf, gets 2nd; Fast Freddy loses again; Fast Freddy Contesthttps://spark.parkland.edu/prospectus_1979/1007/thumbnail.jp
The number field sieve
The number field sieve is an algorithm to factor integers of the form for small positive and . The authors present a report on work in progress on this algorithm. They informally describe the algorithm, discuss several implementation related aspects, and present some of the factorizations obtained so far. They also mention some solutions to the problems encountered when generalizing the algorithm to general integers using an idea of Buhler and Pomerance. It is not unlikely that this leads to a general purpose factoring algorithm that is asymptotically substantially faster than the fastest factoring algorithms known so far, like the multiple polynomial quadratic siev
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Arthroscopic hip surgery compared with physiotherapy and activity modification for the treatment of symptomatic femoroacetabular impingement: multicentre randomised controlled trial.
OBJECTIVE: To compare arthroscopic hip surgery with physiotherapy and activity modification for improving patient reported outcome measures in patients with symptomatic femoroacetabular impingement (FAI). DESIGN: Two group parallel, assessor blinded, pragmatic randomised controlled trial. SETTING: Secondary and tertiary care centres across seven NHS England sites. PARTICIPANTS: 222 participants aged 18 to 60 years with symptomatic FAI confirmed clinically and with imaging (radiography or magnetic resonance imaging) were randomised (1:1) to receive arthroscopic hip surgery (n=112) or a programme of physiotherapy and activity modification (n=110). Exclusion criteria included previous surgery, completion of a physiotherapy programme targeting FAI within the preceding 12 months, established osteoarthritis (Kellgren-Lawrence grade ≥2), and hip dysplasia (centre-edge angle <20 degrees). INTERVENTIONS: Participants in the physiotherapy group received a goal based programme tailored to individual patient needs, with emphasis on improving core stability and movement control. A maximum of eight physiotherapy sessions were delivered over five months. Participants in the arthroscopic surgery group received surgery to excise the bone that impinged during hip movements, followed by routine postoperative care. MAIN OUTCOME MEASURES: The primary outcome measure was the hip outcome score activities of daily living subscale (HOS ADL) at eight months post-randomisation, with a minimum clinically important difference between groups of 9 points. Secondary outcome measures included additional patient reported outcome measures and clinical assessment. RESULTS: At eight months post-randomisation, data were available for 100 patients in the arthroscopic hip surgery group (89%) and 88 patients in the physiotherapy programme group (80%). Mean HOS ADL was 78.4 (95% confidence interval 74.4 to 82.3) for patients randomised to arthroscopic hip surgery and 69.2 (65.2 to 73.3) for patients randomised to the physiotherapy programme. After adjusting for baseline HOS ADL, age, sex, and study site, the mean HOS ADL was 10.0 points higher (6.4 to 13.6) in the arthroscopic hip surgery group compared with the physiotherapy programme group (P<0.001)). No serious adverse events were reported in either group. CONCLUSIONS: Patients with symptomatic FAI referred to secondary or tertiary care achieve superior outcomes with arthroscopic hip surgery than with physiotherapy and activity modification. TRIAL REGISTRATION: ClinicalTrials.gov NCT01893034.NIHR BRC oxfor
How to select a chiropractor for the management of athletic conditions
<p>Abstract</p> <p>Background</p> <p>Chiropractors are an integral part of the management of musculoskeletal injuries. A considerable communication gap between the chiropractic and medical professions exists. Subsequently referring allopathic practitioners lack confidence in picking a chiropractic practitioner with appropriate management strategies to adequately resolve sporting injuries. Subsequently, the question is often raised: "how do you find a good chiropractor?".</p> <p>Discussion</p> <p>Best practice guidelines are increasingly suggesting that musculoskeletal injuries should be managed with multimodal active and passive care strategies. Broadly speaking chiropractors may be subdivided into "modern multimodal" or "classical" (unimodal) in nature. The modern multimodal practitioner is better suited to managing sporting injuries by incorporating passive and active care management strategies to address three important phases of care in the continuum of injury from the acute inflammation/pain phase to the chronic/rehabilitation phase to the injury prevention phase. In contrast, the unimodal, manipulation only and typically spine only approach of the classical practitioner seems less suited to the challenges of the injured athlete. Identifying what part of the philosophical management spectrum a chiropractor falls is important as it is clearly not easily evident in most published material such as Yellow Pages advertisements.</p> <p>Summary</p> <p>Identifying a chiropractic practitioner who uses multimodal treatment of adequate duration, who incorporates active and passive components of therapy including exercise prescription whilst using medical terminology and diagnosis without mandatory x-rays or predetermined treatment schedules or prepaid contracts of care will likely result in selection of a chiropractor with the approach and philosophy suited to appropriately managing athletic conditions. Sporting organizations and associations should consider using similar criteria as a minimum standard to allow participation in health care team selections.</p
A descriptive study of a manual therapy intervention within a randomised controlled trial for hamstring and lower limb injury prevention
The journal has been informed by its publisher BioMed Central that contrary to the statement in this article [Wayne Hoskins, Henry Pollard, Chiropractic & Osteopathy 2010, 18:23], they have been advised by the authors' institution Macquarie University, that its Human Research Ethics Committee did not approve this study. Because the study was conducted without institutional ethics committee approval it has been retracted
A multiscale hybrid model for pro-angiogenic calcium signals in a vascular endothelial cell
Cytosolic calcium machinery is one of the principal signaling mechanisms by which endothelial cells (ECs) respond to external stimuli during several biological processes, including vascular progression in both physiological and pathological conditions. Low concentrations of angiogenic factors (such as VEGF) activate in fact complex pathways involving, among others, second messengers arachidonic acid (AA) and nitric oxide (NO), which in turn control the activity of plasma membrane calcium channels. The subsequent increase in the intracellular level of the ion regulates fundamental biophysical properties of ECs (such as elasticity, intrinsic motility, and chemical strength), enhancing their migratory capacity. Previously, a number of continuous models have represented cytosolic calcium dynamics, while EC migration in angiogenesis has been separately approached with discrete, lattice-based techniques. These two components are here integrated and interfaced to provide a multiscale and hybrid Cellular Potts Model (CPM), where the phenomenology of a motile EC is realistically mediated by its calcium-dependent subcellular events. The model, based on a realistic 3-D cell morphology with a nuclear and a cytosolic region, is set with known biochemical and electrophysiological data. In particular, the resulting simulations are able to reproduce and describe the polarization process, typical of stimulated vascular cells, in various experimental conditions.Moreover, by analyzing the mutual interactions between multilevel biochemical and biomechanical aspects, our study investigates ways to inhibit cell migration: such strategies have in fact the potential to result in pharmacological interventions useful to disrupt malignant vascular progressio
The role of lumbar puncture in children with suspected central nervous system infection
BACKGROUND: The use of the lumbar puncture in the diagnosis of central nervous system infection in acutely ill children is controversial. Recommendations have been published but it is unclear whether they are being followed. METHODS: The medical case notes of 415 acute medical admissions in a children's hospital were examined to identify children with suspected central nervous system infection and suspected meningococcal septicaemia. We determined whether lumbar punctures were indicated or contraindicated, whether they had been performed, and whether the results contributed to the patients' management. RESULTS: Fifty-two children with suspected central nervous system infections, and 43 with suspected meningococcal septicaemia were identified. No lumbar punctures were performed in patients with contraindications, but only 25 (53%) of 47 children with suspected central nervous system infection and no contraindications received a lumbar puncture. Lumbar puncture findings contributed to the management in 18 (72%) of these patients, by identifying a causative organism or excluding bacterial meningitis. CONCLUSION: The recommendations for undertaking lumbar punctures in children with suspected central nervous system infection are not being followed because many children that should receive lumbar punctures are not getting them. When they are performed, lumbar puncture findings make a useful contribution to the patients' management
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