Distribution of Farey Fractions in Residue Classes and Lang--Trotter Conjectures on Average

We prove that the set of Farey fractions of order $T$, that is, the set \{\alpha/\beta \in \Q : \gcd(\alpha, \beta) = 1, 1 \le \alpha, \beta \le T\}, is uniformly distributed in residue classes modulo a prime $p$ provided T \ge p^{1/2 +\eps} for any fixed \eps>0. We apply this to obtain upper bounds for the Lang--Trotter conjectures on Frobenius traces and Frobenius fields ``on average'' over a one-parametric family of elliptic curves

Optimization of methods of diagnosis and surgical treatment of patients with thyroid nodules

Scopul lucrării. Nodulii tiroidieni sunt leziuni distincte ale parenchimului tiroidian, determinați de multiple patologii tiroidiene benigne și maligne, care primar necesită o evaluare amplă pentru depistarea procesului malign și tratament chirurgical în volum adecvat. Scopul studiului este optimizarea metodelor de diagnostic al pacienților cu noduli tiroidieni pentru ameliorarea rezultatelor tratamentului chirurgical. Materiale şi metode. Studiul a inclus 124 pacienți, de vârsta cuprinsă între 19 și 71 ani, cu noduli tiroidieni apreciați clinic și paraclinic inițial prin teste serice și ultrasonografia glandei tiroide, completată după caz de dopplerografie, sonoelastografie, scintigrafia glandei tiroide, puncție-aspirație cu ac fin și intraoperator examen histologic extemporaneu a piesei operatorii cu suspiciune de malignitate. Toți pacienții au fost supuși intervenției chirurgicale conform indicațiilor. Interpretarea rezultatelor obținute s-a efectuat în baza rezultatului histopatologic. Rezultate. Tumori maligne depistate histopatologic au inclus 22 (17,74%) cazuri. Examenul histologic extemporaneu a prezentat acuratețea cea mai mare comparativ cu celelalte metode de diagnostic – 92,68% și a permis extinderea într-o ședință operatorie a volumului tiroidectomiei în 14 cazuri malign confirmate. Pareza tranzitorie de nerv recurent al laringelui a fost unica complicație postoperatorie la 1 (0,8%) pacient. Recidiva maladiei sau alte complicații nu s-au depistat pe parcursul a 24 luni de monitorizare postoperatorie a pacienților. Concluzii. Reușita managementului pacienților cu noduli tiroidieni se datorează studiului clinic, imagistic, histologic detaliat și personalizat în fiecare caz, dar și selectarea metodei individuale de tratament cu evitarea temporizării tiroidectomiilor la pacienții cu indicații către tratament chirurgical.Aim of study. Thyroid nodules are distinct lesions of the thyroid parenchyma, caused by multiple benign and malignant thyroid pathologies, which primarily require extensive evaluation for the detection of malignant process and surgical treatment in adequate volume. The purpose is optimization of diagnostic methods of patients with thyroid nodules to improve the results of surgical treatment. Materials and methods. The study included 124 patients, aged between 19 and 71 years, with thyroid nodules clinically and paraclinically evaluated initially by serum tests and ultrasonography of the thyroid gland, completed as appropriate by dopplerography, sonoelastography, scintigraphy of the thyroid gland, fine needle aspiration and frozen section of the intraoperative specimen with suspicion of malignancy. All patients underwent surgery as indicated. The interpretation of the obtained results was performed on the basis of the histopathological result. Results. Malignant tumors histopathologically detected included 22 (17.74%) cases. The extemporaneous histological examination showed the highest accuracy compared to the other diagnostic methods – 92,68% and allowed the extension in one operative session of the thyroidectomy volume in 14 confirmed malignant cases. Transient paresis of the larynx recurrent nerve was the only postoperative complication in 1 (0,8%) patient. Relapse of the disease or other complications were not detected during 24 months of postoperative monitoring of patients. Conclusions. The success of the management of patients with thyroid nodules is due to the detailed and personalized clinical, imaging, histological study in each case, but also the selection of the individual method of treatment with the avoidance of thyroidectomy timing in patients with indications to surgical treatment

Resonant, broadband and highly efficient optical frequency conversion in semiconductor nanowire gratings at visible and UV wavelengths

Using a hydrodynamic approach we examine bulk- and surface-induced second and third harmonic generation from semiconductor nanowire gratings having a resonant nonlinearity in the absorption region. We demonstrate resonant, broadband and highly efficient optical frequency conversion: contrary to conventional wisdom, we show that harmonic generation can take full advantage of resonant nonlinearities in a spectral range where nonlinear optical coefficients are boosted well beyond what is achievable in the transparent, long-wavelength, non-resonant regime. Using femtosecond pulses with approximately 500 MW/cm2 peak power density, we predict third harmonic conversion efficiencies of approximately 1% in a silicon nanowire array, at nearly any desired UV or visible wavelength, including the range of negative dielectric constant. We also predict surface second harmonic conversion efficiencies of order 0.01%, depending on the electronic effective mass, bistable behavior of the signals as a result of a reshaped resonance, and the onset fifth order nonlinear effects. These remarkable findings, arising from the combined effects of nonlinear resonance dispersion, field localization, and phase-locking, could significantly extend the operational spectral bandwidth of silicon photonics, and strongly suggest that neither linear absorption nor skin depth should be motivating factors to exclude either semiconductors or metals from the list of useful or practical nonlinear materials in any spectral range.Comment: 12 pages, 4 figure

The role of multimodal neuromonitoring during anesthesia for ablation of giant endocranial tumors

Catedra de anesteziologie și reanimatologie nr.2, Catedra de anesteziologie și reanimatologie nr.1 „Valeriu Ghereg”, Catedra de neurochirurgie, USMF „Nicolae Testemițanu”, Chișinău, Republica Moldova, Conferința stiințifică „Nicolae Anestiadi – nume etern al chirurgiei basarabene” consacrată centenarului de la nașterea profesorului Nicolae Anestiadi 26 august 2016Material şi metode. În studiu au fost incluse 2 loturi de pacienţi: I lot– 6 pacienţi cărora li s-a administrat anestezie combinată (i/v + pivot inhalator cu sevofluran); lotul II– 5 pacienţi cărora li s-a administrat anestezie totală intravenoasă (propofol+fentanil). Monitoring: TAs, TAd, TAm (invaziv), PVC, echilibru acidobazic, gazos (arteră şi venă periferică, bulbul jugular), electrolitic, acidul lactic, diurezei orară, PESS. Discuţii. În lotul pacienţilor cu anestezie inhalatorie s-a determinat o incidenţă înaltă a depresiei hemodinamice profunde (Tam - 74,3 mmHg, p= 0,02). Tot aici s-a determinat: utilizarea dozelor mai mici de analgetice şi miorelaxante (sol. atracurium bromid 0,35-0,4mg/kg) , trezire mai rapidă, incidenţă mai scăzută a greții şi tremorului postoperator. S-a reuşit efectuarea mai veridică a neuromonitorigului, datorită cantităţii mai mici de miorelaxante utilizate. La pacienţii cu anestezie intravenoasă s-a determinat o stabilitate hemodinamică (Tam - 82,7 mmHg, p ≤ 0,05), hemoragie intraoperatorie nesemnificativă. În lotul dat s-a reuşit efectuarea neuromonitorigului, cu doze obişnuite de miorelaxante (sol. atracurium bromid 0,5 mg/kg). Concluzii. Tehnicile descrise pot fi utilizate pentru neuromonitorizare multimodală în ablaţia de tumori endocraniene. Tehnica de anestezie inhalatorie, respectând farmacocinetica preparatelor, ar putea fi de preferat, din cauza evitării riscurilor de supra - sau sub dozare de medicamente anestezice, oferind o trezire mai rapidă, cu o evaluarea neurologică imediată, care este extrem de importantă.Materials and methods. The study included two groups of patients: I-st group - 6 patients receiving combined anesthesia (i / v + inhaled sevoflurane); II-nd group - 5 patients who received intravenous anesthesia (propofol + fentanyl).Monitoring: sBP, dBP, mBP (invasive), CVP, acid-base, gas (peripheral artery and vein, jugular bulb) and electrolytic balances, lactic acid, hourly diuresis, neurology evoked potentials. Discussion. In the group of patients with inhalation anesthesia was determined a higher incidence of hemodynamic depression (Tam - 74,3 mmHg, p= 0,02). Also it was determined: use of lower doses of analgetics and muscle relaxants (sol. atracurium bromid 0,35-0,4mg/kg), faster awakening, lower incidence of postoperative nausea and tremors. We managed a more accurate recording of evoked potentials due to the small amount of muscle relaxant used. In patients with intravenous anesthesia was determined a more stable BP (mBP - 82,7 mmHg, p ≤ 0,05), less intraoperative bleeding. In the group given was carrying neuromonitorigului managed with dose of muscle relaxant common (ground. atracurium aromide 0.5 mg / kg). Conclusions. The techniques described can be used for multimodal neuromonitoring in ablation of tumor endocranial. Inhalational anesthesia technique, respecting the pharmacokinetics preparations could be preferable because avoid the risks of over - or under dosage of anesthetic agents, providing an awakening faster with immediate neurological evaluation, which is extremely important

Quasi-static Response of a Timoshenko Beam Loaded by an Elastically Supported Moving Rigid Beam

The present paper is concerned with the quasi-static response of an elastic beam, loaded by a rigid beam, which is slowly transported along the elastic beam. The elastic beam is modelled as a Timoshenko beam. The present paper provides a limiting case of the model with constant distributed load that is often considered in the study of transported masses. The rigid beam is connected to the Timoshenko beam by means of an interface modelled as a Winkler foundation. We present a non-dimensional study on the influence of the interface stiffness upon the displacement, bending moment and shear force of the Timoshenko beam, when the rigid beam is assumed to suffer a prescribed transverse displacement. Special emphasis is laid on the distribution of pressure transmitted by the interface between the Timoshenko beam and the rigid beam. Considerable pressure concentrations are found to take place and the locations of the maximum bending moments in the Timoshenko beam move towards the ends of the rigid beam

Modeling of airport rigid pavement structure made of RCC and recycled cement concrete for complex configuration of landing gears

This paper presents the results of the research undertaken by the authors in the frame of the postdoctoral program 4D-POSTDOC. After a short introduction on the actual status of structural design of airport pavements including geometrical and loading characteristics of complex loading gears, the modeling and the structural design of airport rigid pavements, constructed with conventional and various recycled materials, using the finite element method, is described. The main objective of this research program was to elaborate a design method which, beside the complex landing gear including six footprint tires, all specific parameters related with the recycled materials and with conventional and reinforce rolled compacted concrete (RCC) technologies are included. Finally, practical design diagrams for structural design of the concrete slabs, including their specific correlation function, used for the construction of the Airbus-A380 runway are presented.(undefined

Field Localization and Enhancement of Phase Locked Second and Third Harmonic Generation in Absorbing Semiconductor Cavities

We predict and experimentally observe the enhancement by three orders of magnitude of phase mismatched second and third harmonic generation in a GaAs cavity at 650nm and 433nm, respectively, well above the absorption edge. Phase locking between the pump and the harmonics changes the effective dispersion of the medium and inhibits absorption. Despite hostile conditions the harmonics become localized inside the cavity leading to relatively large conversion efficiencies. Field localization plays a pivotal role and ushers in a new class of semiconductor-based devices in the visible and UV ranges

Nickel catalyst faceting in plasma-enhanced direct current chemical vapor deposition of carbon nanofibers

8 pagesInternational audienceVertically aligned multi-walled carbon nanofibers (CNFs) were grown by plasma-enhanced chemical vapor deposition with Ni catalysts on the top of nanofibers. Transmission electron microscopy was used to study the morphology and crystallography of Ni catalysts, which are essential for the nucleation and growth of CNFs. A model for the faceted shape of Ni catalytic particles is proposed. It is shown that the exposed polyhedral surfaces of Ni catalytic particles for vertically aligned CNFs are composed of {111}, {110}, and {100}, a faceting that appears to be characteristic of the growth atmosphere