426 research outputs found
On direct numerical treatment of hypersingular integral equations arising in mechanics and acoustics
In this paper we present a treatment of hypersingular integral equations,
which have relevant applications in many problems of wave dynamics, elasticity
and fluid mechanics with mixed boundary conditions. The main goal of the
present work is the development of an efficient direct numerical collocation
method. The paper is completed with two examples taken from crack theory and
acoustics: the study of a single crack in a linear isotropic elastic medium,
and diffraction of a plane acoustic wave by a thin rigid screen.Comment: accepted by Acta Mechanica, 19 pages, 3 figure
High temperatures during microsporogenesis fatally shorten pollen lifespan
Many crop species are cultivated to produce seeds and/or fruits and therefore need reproductive success to occur. Previous studies proved that high temperature on mature pollen at anther dehiscence reduce viability and germinability therefore decreasing crop productivity. We hypothesized that high temperature might affect pollen functionality even if the heat treatment is exerted only during the microsporogenesis. Experimental data on Solanum lycopersicum ‘Micro-Tom’ confirmed our hypothesis. Microsporogenesis successfully occurred at both high (30 °C) and optimal (22 °C) temperature. After the anthesis, viability and germinability of the pollen developed at optimal temperature gradually decreased and the reduction was slightly higher when pollen was incubated at 30 °C. Conversely, temperature effect was eagerly enhanced in pollen developed at high temperature. In this case, a drastic reduction of viability and a drop-off to zero of germinability occurred not only when pollen was incubated at 30 °C but also at 22 °C. Further ontogenetic analyses disclosed that high temperature significantly speeded-up the microsporogenesis and the early microgametogenesis (from vacuolated stage to bi-cellular pollen); therefore, gametophytes result already senescent at flower anthesis. Our work contributes to unravel the effects of heat stress on pollen revealing that high temperature conditions during microsporogenesis prime a fatal shortening of the male gametophyte lifespan
Ultrasound-guided percutaneous treatment of a calcific acromioclavicular joint: A case report
Rationale:Calcific tendinopathy is one of the most frequent causes of nontraumatic shoulder pain. However, intra-articular calcifications appear to be an infrequent condition. We herein report a rare case study of an intra-articular calcification of the acromioclavicular joint.Patient concerns:A 46-year-old man presented with an acute pain in the anterior superior region of the left shoulder which also radiated to the left cervical region. The man during the physical evaluation also presented severe functional limitation of the shoulder movements in all planes of motion.Diagnoses:The diagnosis was carried out through a radiographic and an echotomographic examination, highlighting the intra-articular calcific formation associated to a reactive inflammatory reaction.Interventions:An ultrasound-guided percutaneous treatment following the guidelines for calcific tendinopathy of the shoulder was carried out.Outcomes:The posttreatment was satisfactory with the disappearance of the pain and the recovery of the shoulder movements in all planes of motion.Lessons:We can affirm that the ultrasound-guided percutaneous treatment in patients with calcification of the acromion-clavicular joint represents a valid and nonpainful therapeutic treatment
Report on advances for pediatricians in 2018: allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery.
This review reported notable advances in pediatrics that have been published in 2018. We have highlighted progresses in allergy, cardiology, critical care, endocrinology, hereditary metabolic diseases, gastroenterology, infectious diseases, neonatology, nutrition, respiratory tract disorders and surgery. Many studies have informed on epidemiologic observations. Promising outcomes in prevention, diagnosis and treatment have been reported. We think that advances realized in 2018 can now be utilized to ameliorate patient car
Status of Salerno Laboratory (Measurements in Nuclear Emulsion)
A report on the analysis work in the Salerno Emulsion Laboratory is
presented. It is related to the search for nu_mu->nu_tau oscillations in CHORUS
experiment, the calibrations in the WANF (West Area Neutrino Facility) at Cern
and tests and preparation for new experiments.Comment: Proc. The First International Workshop of Nuclear Emulsion Techniques
(12-24 June 1998, Nagoya, Japan), 15 pages, 11 figure
Classification and imaging of ankle impingement syndromes.
Learning Objectives:
To review the classification of ankle impingement syndromes. To describe and illustrate the spectrum of appearance of ankle impingement syndromes using conventional radiography (CR), multidetector computed tomography (MDCT), ultrasonography (US), magnetic resonance imaging (MRI), and MR arthrography (MRA).
Background:
Ankle impingement syndromes are a spectrum of diseases common in both athletic and general population and depend on many causes that can be distinguished by the type of tissue which determines the conflict (bone, fibrous, synovial).
In general, classification of ankle impingement syndromes takes into account the anatomical site relative to the tibio-tarsal joint, and thus they may be classified as anterior, antero-medial, antero-lateral, posterior and postero-medial.
Imaging findings:
CR alone already suffices to demonstrate a bone impingement in most cases, while there is necessity to use MDCT where the site of impingement is in an anatomical site not clearly demonstrable by CR because of the presence of superimposed structures.
US has the ability to recognize the presence of an anterior impingement and it may assess tendon disorders (stenosing tenosynovitis) which may be an associate sign of an impingement syndrome.
MRI is the method of choice to assess synovial or fibrous impingement syndromes thanks to its excellent contrast resolution. MRA is used when there is capsular thickening that could not be detected by simple MRI.
Conclusion:
Diagnostic imaging has a very important role in the recognition of the cause of impingement and of the anatomical site where such a conflict takes place, thus allowing a correct therapeutic management
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