Search for neutrino radiative decays during a total solar eclipse

We present the results of the measurements performed in the occasion of the 2001 total solar eclipse, looking for visible photons emitted through a possible radiative decay of solar neutrinos. We establish lower limits for the \nu_2 and \nu_3 proper lifetimes above 10^3 s/eV, for neutrino masses larger than 10^{-2} eV.Comment: 11 pages, 7 figures, presented at AHEP2003, Valenci

Statics and kinetics at the nematic­-isotropic interface: effects of biaxiality

We use the Landau-de Gennes theory of a nematic liquid crystal to investigate anew aspects of the properties of the interface between the isotropic and nematic liquid crystal phases of the same fluid. The equations of the static interface have been solved, both numerically and using asymptotic analysis, with an emphasis on the effect of inclusion of the order parameter biaxiality on the physical properties. We have compared the results of the exact solutions to the commonly used de Gennes ansatz, which assumes positive and uniform unixiality through the interface. Although the de Gennes ansatz in general gives good results, when bend and splay elastic constants dominate over the twist constants, it can lead to errors of up to 10% in the surface energy. The asymptotic analysis also shows that, by contrast with the de Gennes ansatz, the order parameter wings in the isotropic phase exhibit negative order parameter, with principal axis perpendicular to the surface. For moving interfaces, using an approximation which at this stage does not yet include hydrodynamic coupling, we have compared our results with the analogue of the de Gennes ansatz used by the present authors in an earlier paper. We find that including biaxiality leads to larger effects in the dynamic than in the static properties, and that whereas this is essentially a perturbation to the energy, the velocity of the moving interface can be significantly slowed down. The slowing down effects are strongly correlated with surface biaxiality, but both effects seem to be diminished when the isotropic phase is advancing

Band gaps in pseudopotential self-consistent GW calculations

For materials which are incorrectly predicted by density functional theory to be metallic, an iterative procedure must be adopted in order to perform GW calculations. In this paper we test two iterative schemes based on the quasi-particle and pseudopotential approximations for a number of inorganic semiconductors whose electronic structures are well known from experiment. Iterating just the quasi-particle energies yields a systematic, but modest overestimate of the band gaps, confirming conclusions drawn earlier for CaB_6 and YH_3. Iterating the quasi-particle wave functions as well gives rise to an imbalance between the Hartree and Fock potentials and results in bandgaps in far poorer agreement with experiment.Comment: 5 pages, 2 figures, 2 table

Severe complication in acute apendicitis (clinical case)

Spitalul raional Briceni, secția chirurgie, Briceni, Moldova, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Introducere. Tratamentul apendicitei acute la vârstnici necesită eforturi terapeutico – chirurgicale deosebite. În cazurile cu complicație severe letalitatea atinge 60-70%. Scopul. Atenționarea chirurgilor practici la evoluția drastică a apendicitei. Material şi metode. Pacientul M. în vârstă de 76 ani internat în secție de chirurgie IMSP a Spitalul Raional Briceni pe 24 noiembrie 2009 la ora 9.40 cu diagnosticul de abdomen acut. S-a îmbolnăvit acum 4 zile în urmă. Obiectiv: starea gravă, pulsul 116-120 ׳, tensiunea arterială 110-60 mmHg. Abdomenul balonat, dureros la palpație cu defense muscular pe tot flancul drept. Datele paraclinice: leucocitoza 23,4; nesegmentate 18%. S-a efectuat radiografia pe gol, USG, laparoscopia. S-a stabilit diagnoza – peritonită purulentă difuză. După pregătire preoperatorie scurtă pacientul a fost operat. Diagnosticul postoperator: Apendicita acută gangrenoasă perforativă. Abces apendicular retroperitoneal, retrocecal. Peritonită purulentă difuză. Perioada postoperatorie cu agravare. Pe 28.XI.2009 s-a solicitat consultația specialistului pe aviasan. Pacientul reoperat cu incizii în regiunea lombară şi drenarea flegmonului retroperitoneal şi abcesului subdiafragmal. Prin toracocenteză sa drenat cavitatea pleurală. Evoluția ulterioară gravă cu delir în primele 3 zile. Tratament infuzional intensiv, terapia antibacteriană, pansamente agresive (sub anestezie generală i/v), lavaj continuu cu antiseptice. S-a obținut ameliorarea stării pacientului. Pe 09.XII au fost aplicate suturi secundare. Pe 15 XII s-a externat din secție. Concluzii. Adresarea precoce a suferinzilor ar fi momentul optimal de prevenire a urmărilor drastice. Rezolvarea complicațiilor grave necesită eforturi maxime chirurgical terapeutice inclusiv consultația colegilor experimentați.Introduction. The management of acute appendicitis in elderly patients has a specific approach. The cases involving severe complications have a mortality rate as high as 60-70%.Aim of this study: To reinsure regardfulness of practical surgeons to the drastic evolution of acute appendicitis. Material and methods: Patient M., 76 years old, attended to the division of surgery of Briceni Regional Hospital on the 24’ th of November 2009 at 9:40 AM, diagnosed for acute abdomen. The onset of symptoms was four days before hospitalization. The patient was in a severe state, a bloating abdomen, tenderness at palpation with muscular rigidity involving the right flank. At laboratory findings the white blood count showed leucocytosis – 23,4. X-ray of the abdomen, Ultrasonography and laparoscopy have been performed. The diagnosis of diffuse purulent peritonitis was put. After a short preoperative care the patient underwent surgery. Postoperative diagnosis: Acute gangrenous perforated appendicitis. Retroperitoneal abscess with retrocecal localization. Diffuse purulent peritonitis. The postoperative period with a worsening of the general state. On the 28’th of November the patient was consulted by “AVIASAN” specialist. The patient was reoperated. A lumbar incision was used to drain the retroperitoneal phlegmon and the subdiaphragmal abscess. Thoracocentesis was performed to drain the pleural cavity. For the following three days the patient has been in a severe, delirious state. Intensive infusional, antibacterial treatment with aggressive wound care (under general intravenous anesthesia), and continuous pleural lavage using antiseptic agents led to improvement of the general state of the patient. Conclusions: The early hospital attendance of patients is is crucial for prevention of such severe complications. Management of such complications involves maximal surgical and therapeutic efforts including consultation of more experienced specialists

Minimal structures, punctually m-open functions in the sense of Kuratowski and bitopological spaces

Byusingm-open functions from a topological space into an m-space, we establish the unified theory for several weak forms of open functions in the sense of Kuratowski between bitopological spaces

Fixed-Point Results on Complete G-Metric Spaces for Mappings Satisfying an Implicit relation of New Type

We prove general fixed-point theorems (generalizing some recent results) in a complete G-metric space.Доведено загальні теореми про нерухому точку у повних G-метричних просторах, що узагальнюють дєякі результати, отримані нещодавно

Monte Carlo simulation of an experiment looking for radiative solar neutrino decays

We analyse the possibility of detecting visible photons from a hypothetical radiative decay of solar neutrinos. Our study is focused on the simulation of such measurements during total solar eclipses and it is based on the BP2000 Standard Solar Model and on the most recent experimental information concerning the neutrino properties.Comment: 13 pages, 10 figures, accepted by Astropart. Phy

Obtaining lignin nanoparticles by sonication

Lignin, the main natural aromatic polymer was always aroused researchers interest. Currently around 90% of this biomaterial is burned for energy. It has a very complex and complicated structure which depends on the separation method and plant species, what determine difficulties to use as a raw material widely. This research presents a physical method to modify lignin by ultrasonic irradiation in order to obtain nanoparticles. The nanoparticles synthesized were dimensionally and morphologically characterized. At the same time the preoccupations were to determine the structural and compositional changes that occurred after sonication. To achieve this, two types of commercial lignins (wheat straw and Sarkanda grass) were used and the modifications were analyzed by FTIR-spectroscopy, GPC-chromatography, (31)P-NMR-spectroscopy and HSQC0. The results confirm that the compositional and structural changes of nanoparticles obtained are not significantly modified at the intensity applied but depend on the nature of lignin