An Analogue of Holstein-Primakoff and Dyson Realizations for Lie Superalgebras. The Lie superalgebra sl(1/n)

An analogue of the Holstein-Primakoff and of the Dyson realization for the Lie superalgebra $sl(1/n)$ is written down. The expressions are formally the same as for the Lie algebra $sl(n+1)$, however in the latter the Bose operators have to be replaced with Fermi operators.Comment: TeX, 6 page

Comparing all-optical switching in synthetic-ferrimagnetic multilayers and alloys

We present an experimental and theoretical investigation of all-optical switching by single femtosecond laser pulses. Our experimental results demonstrate that, unlike rare earth-transition metal ferrimagnetic alloys, Pt/Co/[Ni/Co]$_N$/Gd can be switched in the absence of a magnetization compensation temperature, indicative for strikingly different switching conditions. In order to understand the underlying mechanism, we model the laser-induced magnetization dynamics in Co/Gd bilayers and GdCo alloys on an equal footing, using an extension of the microscopic three-temperature model to multiple magnetic sublattices and including exchange scattering. In agreement with our experimental observations, the model shows that Co/Gd bilayers can be switched for an arbitrary thickness of the Co layer, i.e, even far away from compensating the total Co and Gd magnetic moment. We identify the switching mechanism in Co/Gd bilayers as a front of reversed Co magnetization that nucleates at the Co/Gd interface and propagates through the Co layer driven by exchange scattering.Comment: Published versio

Науково-теоретична конференція «Гармонізація науки і вищої освіти в інформаційному суспільстві»

У Києві 30−31 березня 2011 року в Національному авіаційному університеті відбулася науково-теоретична конференція «Гармонізація науки і вищої освіти в інформаційному суспільстві»

Implications of invariance of the Hamiltonian under canonical transformations in phase space

We observe that, within the effective generating function formalism for the implementation of canonical transformations within wave mechanics, non-trivial canonical transformations which leave invariant the form of the Hamilton function of the classical analogue of a quantum system manifest themselves in an integral equation for its stationary state eigenfunctions. We restrict ourselves to that subclass of these dynamical symmetries for which the corresponding effective generating functions are necessaarily free of quantum corrections. We demonstrate that infinite families of such transformations exist for a variety of familiar conservative systems of one degree of freedom. We show how the geometry of the canonical transformations and the symmetry of the effective generating function can be exploited to pin down the precise form of the integral equations for stationary state eigenfunctions. We recover several integral equations found in the literature on standard special functions of mathematical physics. We end with a brief discussion (relevant to string theory) of the generalization to scalar field theories in 1+1 dimensions.Comment: REVTeX v3.1, 13 page

An Evidence-Based Rationale for Dose De-escalation of Subcutaneous Atezolizumab

Background: Atezolizumab is a programmed death-ligand 1 (PD-L1) checkpoint inhibitor for the treatment of different forms of cancer. The subcutaneous formulation of atezolizumab has recently received approval. However, treatment with atezolizumab continues to be expensive, and the number of patients needing treatment with this drug continues to increase. Objective: We propose two alternative dosing regimens for subcutaneous atezolizumab to reduce drug expenses while ensuring effective exposure; one may be directly implemented in the clinic. Patients and Methods: We developed two alternative dose interval prolongation strategies based on pharmacokinetic modeling and simulation. The first dosing regimen was based on patients’ weight while maintaining equivalent systemic drug exposure by adhering to Food and Drug Administration (FDA) guidelines for in silico dose adjustments. The second dosing regimen aimed to have a minimum atezolizumab concentration above the 6 µg/mL threshold, associated with 95% intratumoral PD-L1 receptor saturation for at least 95% of all patients. Results: We found that, for the weight-based dosing regimen, the approved 3-week dosing interval could be extended to 5 weeks for patients &lt; 50 kg and 4 weeks for patients weighing 50–65 kg. Besides improving patient convenience, these alternative dosing intervals led to a predicted 7% and 12% cost reduction for either the USA or European population. For the second dosing regimen, we predicted that a 6-week dosing interval would result in 95% of the patients above the 6 µg/mL threshold while reducing costs by 50%. Conclusions: We have developed and evaluated two alternative dosing regimens that resulted in a cost reduction. Our weight-based dosing regimen can be directly implemented and complies with FDA guidelines for alternative dosing regimens of PD-L1 inhibitors. For the more progressive alternative dosing regimen aimed at the intratumoral PD-L1 receptor threshold, further evidence on efficacy and safety is needed before implementation.</p

Partial Dynamical Symmetry in the Symplectic Shell Model

We present an example of a partial dynamical symmetry (PDS) in an interacting fermion system and demonstrate the close relationship of the associated Hamiltonians with a realistic quadrupole-quadrupole interaction, thus shedding new light on this important interaction. Specifically, in the framework of the symplectic shell model of nuclei, we prove the existence of a family of fermionic Hamiltonians with partial SU(3) symmetry. We outline the construction process for the PDS eigenstates with good symmetry and give analytic expressions for the energies of these states and E2 transition strengths between them. Characteristics of both pure and mixed-symmetry PDS eigenstates are discussed and the resulting spectra and transition strengths are compared to those of real nuclei. The PDS concept is shown to be relevant to the description of prolate, oblate, as well as triaxially deformed nuclei. Similarities and differences between the fermion case and the previously established partial SU(3) symmetry in the Interacting Boson Model are considered.Comment: 9 figure

El oxímoron de la protección temporal perpetua: Sirios en Turquía

The crisis in Syria has entered its fifth year, becoming a protracted conflict in international conflict terminology. Based on figures compiled by the United Nations High Commissioner for Refugees (UNHCR), as of March 16, 2016, there were 4.8 million registered Syrians in the neighboring countries of Egypt, Iraq, Jordan, Lebanon, and Turkey. Data provided by the Directorate General of Migration Management (DGMM) in Turkey show that as of March 24, 2016, 2.75 million, or 57 % of the people mentioned above, were registered in Turkey. While 10 percent of the Syrians in Turkey were living in camps, the rest were dispersed in various Turkish cities. Three cities—Şanlıurfa, Istanbul, and Hatay— host more Syrians combined (1.2 million) than the entire European continent, where the total Syrian asylum applications were 935,008 for the period between April 2011 and January 2016.publisher versio

Evaluating predictive pharmacogenetic signatures of adverse events in colorectal cancer patients treated with fluoropyrimidines

The potential clinical utility of genetic markers associated with response to fluoropyrimidine treatment in colorectal cancer patients remains controversial despite extensive study. Our aim was to test the clinical validity of both novel and previously identified markers of adverse events in a broad clinical setting. We have conducted an observational pharmacogenetic study of early adverse events in a cohort study of 254 colorectal cancer patients treated with 5-fluorouracil or capecitabine. Sixteen variants of nine key folate (pharmacodynamic) and drug metabolising (pharmacokinetic) enzymes have been analysed as individual markers and/or signatures of markers. We found a significant association between TYMP S471L (rs11479) and early dose modifications and/or severe adverse events (adjusted OR = 2.02 [1.03; 4.00], p = 0.042, adjusted OR = 2.70 [1.23; 5.92], p = 0.01 respectively). There was also a significant association between these phenotypes and a signature of DPYD mutations (Adjusted OR = 3.96 [1.17; 13.33], p = 0.03, adjusted OR = 6.76 [1.99; 22.96], p = 0.002 respectively). We did not identify any significant associations between the individual candidate pharmacodynamic markers and toxicity. If a predictive test for early adverse events analysed the TYMP and DPYD variants as a signature, the sensitivity would be 45.5 %, with a positive predictive value of just 33.9 % and thus poor clinical validity. Most studies to date have been under-powered to consider multiple pharmacokinetic and pharmacodynamic variants simultaneously but this and similar individualised data sets could be pooled in meta-analyses to resolve uncertainties about the potential clinical utility of these markers

Trends in Drug Costs and Overall Survival in Patients with Metastatic Non-small Cell Lung Cancer in The Netherlands Diagnosed from 2008 Through 2014

BACKGROUND: The Value-Based Health Care concept defines patient value as patient-relevant outcomes divided by costs. The aim of the present study was to assess the development of systemic treatment costs over the years compared with changes in overall survival (OS) at the level of a diagnosis of stage IV non-small cell lung cancer (NSCLC). METHODS: All patients diagnosed (in 2008-2014) with stage IV NSCLC and treated with systemic treatment in six Dutch large teaching hospitals (Santeon network) were included. We collected data on OS and amounts of drug units (milligrams) for every drug in the applied systemic cancer treatments, until death. These amounts were multiplied by Dutch unit costs (Euros/mg) expressed in 2018 Euros to construct total drug costs per line of treatment per patient. Costs for day care visits were added for drugs requiring parenteral administration. RESULTS: Data were collected from 1214 patients. Median OS and mean total drug costs showed no significant variation over the years (p = 0.437 and p = 0.693, respectively). Mean total drug costs per 1 year of survival ranged from €20,665 to €26,438 during the period under study. Costs for first-line systemic treatment were significantly higher in 2011-2014 compared with 2008-2010. CONCLUSION: This study shows that overall drug costs were stable over the years, despite a relative increase in first-line treatment costs. Median OS remained at around 8 months from year to year. These trend data are very relevant as background for the assessment of costs and achieved outcomes in the more recent years