Improved harmonic approximation and the 2D Ising model at T≠TcT\neq T_{c} and h≠0h\neq0

We propose a new method to determine the unknown parameter associated to a self-consistent harmonic approximation. We check the validity of our technique in the context of the sine-Gordon model. As a non trivial application we consider the scaling regime of the 2D Ising model away from the critical point and in the presence of a magnetic field $h$. We derive an expression that relates the approximate correlation length $\xi$, $T-T_c$ and $h$.Comment: 11 pages, Latex, 3 figures. Accepted for publication in Journal of Physics

METABOLICKI OBRT SEROTONINA I DOPAMINA U MOZGU BOLESNIKA SA MOZDANIM ORGANSKIM PSIHOSINDROMOM

Mozdani organski psibosindrom (MOP.5) je u psihijatriji i neuronaukama dijagnosticki entitet uteme!Jen na disJunkciji kognicije, a pos/edica je organskog oftelef!Ja mO:{ga disperzno mu/tikauza/no. Snoremeno»: imidijng d!Jagnostikom nqjceffe je i doka~vano oIteeet!Je mO:{ga kao i gubitak neuronskog kvantuma u MOPS-u. NaIe istraz!tJat!Je je usmereno na utvrilivat!Je alteracije biogenih amina' (serotonina i dopamina) i f!J"ihovih metabolita u bo/esnika sa MOPSom. Stud!Ja obubuata bo/esnike dijagnostikovane kao MOPS sa kauzalnim oIieCet!Jem JJJo:{ga iJifarktnom /e~jom (grupa A), bolesnike sa dugovremenom '{joupotrebom a/koho/a (grupa B), kao i kontro/nu grupu (K). Ako je /ikvor unutraIt!Ja mikrosredina mO:{ga} odnosno neuronal onda nivo i osi/aqje koncentrac!J"e serotonina, dopamina i njihovih metabolita u /ikvoru moraj« ko/etirati sa psihometrijski utordeni»: kognitivnim oItecet!JelJJ. Ovim istrazjvat!Jem je dokazana povezanost neurometabo/ickog i neurobiohemijskog disbalansa u /ikvoru sa di{jimkajoJJJ kognicije kod svih ispitanika: u grupi sa oIteiet!Jem mo:<ga isbemijom i u grupisa oItecet!Jem mozr;a aleobolom. Kljucne reci: serotonin) dopamin, cerebrospinalna teinost, alkoholizam} ishemija mozga UVOD Moz dani organski psihosindrom (MOPS) JC sv c ccsce dijagno sticko opredeljenje u psihijatrijskoj praksi zahvaljujuci razvoju dijagno stickih procedura (EEG, CT i MR endokranijuma) i savremenenih biohemijskih metoda. Dijagnosticka sus tina MOPS-a je psihometrijsko utvrdivanjc o stece nc kognicije i saznanja 0 sp o ljas n oj i unu tras njoj realnosti tih bolesnika. Kognicija i ukupno mentalno covcka su funkcionalni odnos stalne integrativne delatnosti mozga, osnovnog mo zd an og kompartmana -n e ur o n a, odnosno svcukupnog ncuronskog kvantuma Aleksandar Aleksic, Nenad M. Nenadovlc, ... ncurona srnrcu u raznim stanjima moz.danog ostcccnj a, rrn a kao obaveznu posledicu kognitivnu disfunkciju, kako kompleksnu, tako i pojedinacnih saznajnih funkcija. Zbog ish ernicnih lezija mozga i li alkohoIizma dogada se tipicna difuzna redukcija neuronskog broja. Ovakva o steccnja mozga pored ncuro loskog deficita imaju iz raz en e porernecaje mentalnog sklada u funkcionisanju ukupnog ps ih ickog Nase is tr az ivanje je zasnovano na dokazivanju povezanosti oscilacija porcmecenog neurobiohemizma mozga i stepena o stece nja kognicije, kod bolesnika sa lediranim mozgom ishemijom ili alkoholom. cn.j RADA Is traz iv acki cilj ovog rada je da se kod bolesnika sa verifikovanim MOPS-om, nastalim kao posledica ishemije mozga ili alkoholizmom, u bolnickirn uslovima, utvrdi korelacija nrvo a dopamina, serotonina i njihovih metabolita u likvoru sa stepenom METABOLICKI OBRT SEROTONINA I DOPAMINA U ... ------ o s te ce nja kognitivnih funkcija. METODOLOGIJA ISTRAZIVANJA Is traziv anje je sprovedeno u hospitalnim uslovima Bolnice za ccrcbrovaskularne bolesti "Sveti Sava", Zavodu za lecenje bolesti zavisnosti i Institutu. z a biohemiju medicinskog fakulteta u Bcogradu. Za postizanje is tr az ivack ih ciljeva sproveli smo m e to do lo sku ekspJoraciju u is traz ivan irn grupama bolesnika. Svi pacijenti, kako u is traz iv anim tako i u kontrolnoj grupi bili su mu s kog pola, starosne dobi 55 do 65 godina. Lstraz.iv anu grupu A ci n i li su bolesnici sa kli ni c ko m dijagnozom MOPS (30 bolesnika), grupu B (12 bolesnika) alkoho licari , a kontrolnu grupu K b o le sn ici bez dokazanc lezijc mozga i bez kognitivnih disfunkcija (10 bolesnika) . U i straz iva nju su ko risce ni sle dici is traz iva ck i metodi: 1. Metod klin ickog i laboratorijskog pregleda ps iho lo skopsihometrijskog testiranja; 2. Stas tisticka obrada dobijenih podataka i rezultata i s traz iv anja. Za postavljanjc dijagnoze MOPS-a primenjivana su n e ur o fiz io lo ska i n eu to r adi o lo ska ispi tivanja (EEG, CT i MR mozga). Dijagnoza alkoholizma je postavljana na osnovu dij agno stickih kriterijuma iz DSM III-R. Za odredivanje nivoa o stcce nja kognicije ko ri sce no je ps iholo sko-ps ihomctrijsko testiranje: modifikovani "Hachinski ishemic score", WB SP forma i Bentonov test vizuelne percepcije. Likvor je lumbalnom punkcijom uziman od pacijenata u kolicini od 2 ml, neposredno nakon utvrdivanja da ispunjavaju dijagno srickc kriterijume, zamrzavan i jednovremeno analiziran metodom HPCL. Dobijeni rezultati su obradeni primenom s ta ti s ticke metodologije za ovakva is traz ivanja. REZULTATIISTRAZIVANJA Nisu nam iz literature poznate studije u kojima su istraz ivani obim, stepen il i posebnost o steceno sti kognicije u alk oh olica ra i bolesnika sa moz danorn ishemijom (MOPS) i njihovo koreIiranje sa Gradacija o scecenja kognicije je izvrSena na osnovu rezultata ostvarenih na testovima: tesko o stccenje kognicije imaju bolesnici koji ni su o stva rili 10 poena na testovima. Srednje tes ko o stecc nje imaju bolesnici Ciji je zbir poena bio od 10 do 20. Lako 'o ste ce nje kognicije postoji kod pacijenata sa ostvarenih 21 do 24 poena. Bez o stecenja kognicije su o ni sa skorom od 25 do maksimalnih 30 poena. Iz Tabclc 1. uo cava s e da te sko o s teccnje kognicijc imaju 22 bolesnika iii 73% iz ispitivane grupe A (bolesnici sa ishemijom mozga) i sarno 3 bolesnika iii 25°/<1 iz i spi tiv an e grupe B (alko ho licari) ; nema utvrdenog tdkog o stecenja kognitivnih funkcija medu bolesnicima kontrolne grupe K. Srednje tcs ko o stcccnjc kognicije utvrdeno je kod 8 (27%) bolesnika ispitivane grupe B, u kontrolnoj grupi K nema bolesnika sa srednje te skim o ste cenj em kognitivnih funkcija. Lak stepen o stccenja kognitivnih funkcija n em a nijedan bolesnik iz ispitivane grupe A niti iz kontrolnc grupc K, a 92 ENGRAMI 22 •. ------dva bolesnika ili 17% iz ispitivane grupe B imaju lako o s te ce nu kogniciju. Odsustvo o ste ce nja kognitivnih funkcija su pokazali svih 10 (100%) bolesnika kontrolne grupe K i nijedan bo le snik iz ispitivanih grupa A i B. Tabela 2. prikazuje nivo serotonina i njegovih metabolita u likvoru bolesnika i z ispitivanih grupa (A i B) i kontrolnc grupe (K). Tabela 2. Nivo serotonina i njegovih metabolita u likvoru bolesnika. Saddaj 5-HT serotonina u likvoru bolesnika ispitivanih grupa A i B (MOPS i alkoholizam) jc z nacajno poviseriog nivoa u odnosu na saddaj 5-HT u likvoru bolesnika kontrolne grupe K. Potvrdena je visoka z nacajno st sta ti stick e razlike 5-HT u bolesnika ispitivanih grupa A i B u odnosu na grupu K. (p<0,05). Sad rz aj metabolita serotonina 5-HIAA u likvoru bolesnika ispitivanih grupa A i B zna caj no je p ovis e n u odnosu na kontrolnu grupu. Nivo metabolita u likvoru ispitivane grupe A (MOPS) zn acajrio je visi u odnosu na nivo u likvoru bolesnika ispitivane grupe B (alkoholicari). Potvrdena je i visoka stati stick a z nacajno st razlike nivoa 5-HIAA u likvoru bolesnika ispitivanih grupa A i B u odnosu na kontrolnu grupu, dok je izmedu ispitivanih grupa p<0,05. ENGRAMI 2

Effect of biased noise fluctuations on the output radiation of coherent beat laser

Effect of biased noise fluctuations on the degree of squeezing as well as the intensity of a radiation generated by a one-photon coherent beat laser is presented. It turns out that the radiation exhibits squeezing inside and outside the cavity under certain conditions. The degree of squeezing is enhanced by the biased noise input significantly in both regions. Despite the presence of the biased environment modes outside the cavity, the degree of squeezing outside the cavity can be greater than or equal to or even less than the cavity radiation depending on the initial preparation of the atomic superposition and amplitude of the external driving radiation. But the intensity of the radiation is found to be lesser outside the cavity regardless of these parameters.Comment: 18 pages, 7 figure

On the Schoenberg Transformations in Data Analysis: Theory and Illustrations

The class of Schoenberg transformations, embedding Euclidean distances into higher dimensional Euclidean spaces, is presented, and derived from theorems on positive definite and conditionally negative definite matrices. Original results on the arc lengths, angles and curvature of the transformations are proposed, and visualized on artificial data sets by classical multidimensional scaling. A simple distance-based discriminant algorithm illustrates the theory, intimately connected to the Gaussian kernels of Machine Learning

Effect of Peierls transition in armchair carbon nanotube on dynamical behaviour of encapsulated fullerene

The changes of dynamical behaviour of a single fullerene molecule inside an armchair carbon nanotube caused by the structural Peierls transition in the nanotube are considered. The structures of the smallest C20 and Fe@C20 fullerenes are computed using the spin-polarized density functional theory. Significant changes of the barriers for motion along the nanotube axis and rotation of these fullerenes inside the (8,8) nanotube are found at the Peierls transition. It is shown that the coefficients of translational and rotational diffusions of these fullerenes inside the nanotube change by several orders of magnitude. The possibility of inverse orientational melting, i.e. with a decrease of temperature, for the systems under consideration is predicted.Comment: 9 pages, 6 figures, 1 tabl

Skin cancers in albinos in a teaching Hospital in eastern Nigeria - presentation and challenges of care

<p>Abstract</p> <p>Background</p> <p>Albinism is a genetic disorder characterized by lack of skin pigmentation. It has a worldwide distribution but is commoner in areas close to the equator like Nigeria. Skin cancers are a major risk associated with albinism and are thought to be a major cause of death in African albinos. Challenges faced in the care of these patients need to be highlighted in order to develop a holistic management approach with a significant public health impact. The aim of the study was to determine the pattern of skin cancers seen in Albinos, and to highlight problems encountered in their management.</p> <p>Method</p> <p>Case records of albinos managed in Imo state University teaching Hospital from June 2007 to May 2009 were reviewed. The data obtained was analyzed using descriptive statistics.</p> <p>Results and discussion</p> <p>In the period under review, albinos accounted for 67% of patients managed for primary skin cancers. There were twenty patients with thirty eight (38) lesions. Sixty one percent of the patients were below 40 years. Average duration of symptoms at presentation was 26 months. The commonest reason for late presentation was the lack of funds. Squamous cell carcinoma was the commonest histologic variant. Most patients were unable to complete treatment due to lack of funds.</p> <p>Conclusion</p> <p>Albinism appears to be the most important risk factor in the development of skin cancers in our environment. Late presentation and poor rate of completion of treatment due to poverty are major challenges.</p

Decompressive cervical laminectomy and lateral mass screw-rod arthrodesis. Surgical analysis and outcome

<p>Abstract</p> <p>Background</p> <p>This study evaluates the outcome and complications of decompressive cervical Laminectomy and lateral mass screw fixation in 110 cases treated for variable cervical spine pathologies that included; degenerative disease, trauma, neoplasms, metabolic-inflammatory disorders and congenital anomalies.</p> <p>Methods</p> <p>A retrospective review of total 785 lateral mass screws were placed in patients ages 16-68 years (40 females and 70 males). All cases were performed with a polyaxial screw-rod construct and screws were placed by using Anderson-Sekhon trajectory. Most patients had 12-14-mm length and 3.5 mm diameter screws placed for subaxial and 28-30 for C1 lateral mass. Screw location was assessed by post operative plain x-ray and computed tomography can (CT), besides that; the facet joint, nerve root foramen and foramen transversarium violation were also appraised.</p> <p>Results</p> <p>No patients experienced neural or vascular injury as a result of screw position. Only one patient needed screw repositioning. Six patients experienced superficial wound infection. Fifteen patients had pain around the shoulder of C5 distribution that subsided over the time. No patients developed screw pullouts or symptomatic adjacent segment disease within the period of follow up.</p> <p>Conclusion</p> <p>decompressive cervical spine laminectomy and Lateral mass screw stabilization is a technique that can be used for a variety of cervical spine pathologies with safety and efficiency.</p

Robustness of circadian clocks to daylight fluctuations: hints from the picoeucaryote Ostreococcus tauri

The development of systemic approaches in biology has put emphasis on identifying genetic modules whose behavior can be modeled accurately so as to gain insight into their structure and function. However most gene circuits in a cell are under control of external signals and thus quantitative agreement between experimental data and a mathematical model is difficult. Circadian biology has been one notable exception: quantitative models of the internal clock that orchestrates biological processes over the 24-hour diurnal cycle have been constructed for a few organisms, from cyanobacteria to plants and mammals. In most cases, a complex architecture with interlocked feedback loops has been evidenced. Here we present first modeling results for the circadian clock of the green unicellular alga Ostreococcus tauri. Two plant-like clock genes have been shown to play a central role in Ostreococcus clock. We find that their expression time profiles can be accurately reproduced by a minimal model of a two-gene transcriptional feedback loop. Remarkably, best adjustment of data recorded under light/dark alternation is obtained when assuming that the oscillator is not coupled to the diurnal cycle. This suggests that coupling to light is confined to specific time intervals and has no dynamical effect when the oscillator is entrained by the diurnal cycle. This intringuing property may reflect a strategy to minimize the impact of fluctuations in daylight intensity on the core circadian oscillator, a type of perturbation that has been rarely considered when assessing the robustness of circadian clocks