Constructions of biangular tight frames and their relationships with equiangular tight frames

We study several interesting examples of Biangular Tight Frames (BTFs) - basis-like sets of unit vectors admitting exactly two distinct frame angles (ie, pairwise absolute inner products) - and examine their relationships with Equiangular Tight Frames (ETFs) - basis-like systems which admit exactly one frame angle. We demonstrate a smooth parametrization BTFs, where the corresponding frame angles transform smoothly with the parameter, which "passes through" an ETF answers two questions regarding the rigidity of BTFs. We also develop a general framework of so-called harmonic BTFs and Steiner BTFs - which includes the equiangular cases, surprisingly, the development of this framework leads to a connection with the famous open problem(s) regarding the existence of Mersenne and Fermat primes. Finally, we construct a (chordally) biangular tight set of subspaces (ie, a tight fusion frame) which "Pl\"ucker embeds" into an ETF.Comment: 19 page

Centrality dependence of hyperon global polarization in Au+Au collisions at RHIC

We present the centrality dependence of Lambda and Anti-Lambda hyperon global polarization in Au+Au collisions at sqrt{s_NN}=62 GeV and 200 GeV measured with the STAR detector at RHIC. Within the precision of the measurement, we observe no centrality dependence of Lambda and Anti-Lambda hyperon global polarization and within our acceptance it is consistent with zero. Different sources of systematic uncertainties (feed down effects, spin precession) are discussed and estimated. The obtained upper limit, |P_{Lambda,Anti-Lambda}| < 0.02, is compared to theoretical predictions discussed recently in literatures.Comment: Talk given at QM 2006, The 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, November 14-20, 2006, Shanghai, China; 4 pages, 2 figure

Measurements of Transverse Spin Effects with the Forward Pion Detector of STAR

Measurements by the STAR collaboration of neutral pion production at large Feynman x (x_F) in the first polarized proton collisions at $\sqrt{s}=200$ GeV were reported previously. Cross sections measured at $\eta=3.3$, 3.8 and 4.0 are found to be consistent with next-to-leading order perturbative QCD calculations. The analyzing power is consistent with zero at negative x_F and at positive x_F up to ~0.3, then grows more positive with increasing x_F. This behavior can be described by phenomenological models including the Sivers effect, the Collins effect or higher twist contributions in the initial and final states. Forward calorimetry at STAR has been extended, and there are plans for further expansion. An integrated luminosity of 6.8 pb^${-1}$ with average beam polarization of 60% from online polarimetry measurements was sampled with the upgraded FPD in the 2006 RHIC run. This data sample will allow for a detailed map of the \pi^0 analyzing power over kinematic variables bounded by 0.3 < x_F < 0.6 and 1.2 < p_T < 5.0 GeV/c at $\sqrt{s}=200$ GeV. The expanded FPD has observed multi-photon final states expected to have "jet-like" characteristics. The transverse spin dependence of jet-like events can discriminate between the Collins and Sivers effects and lead to further progress in understanding the origin of single spin asymmetries in forward particle production. Data were also obtained at $\sqrt{s}=62.4$ GeV for x_F -> 1 to test predictions based on phenomenological fits to earlier STAR results. Recent results, the status of the analysis of 2006 run data and near-term plans will be discussed.Comment: 4 pages, 3 figures, to be published in the proceedings of the 17th International Spin Physics Symposium (SPIN2006), October 2-7, 2006, Kyoto, Japa

Neuroleptic malignant syndrome in a young adult female at the university of Benin Teaching Hospital: a case report

Background: Neuroleptic malignant syndrome is a rare but life-threatening idiosyncratic complication following the use of antipsychotic agents, anaesthesia and surgery. It is characterized by hyperthermia, muscle rigidity, autonomic disturbances and mental state alterations.Case: A 31 year old female weighing 60kg received a depot preparation of Fluphenazine on account of depression with psychotic features observed two days prior to elective Cholecystectomy under general anaesthesia. Surgery and anaesthesia were essentially uneventful. Forty eight hours post-operatively, the patient developed features suggestive of neuroleptic malignant syndrome complicated by aspiration pneumonitis. This necessitated her admission into the intensive care unit. She had prolonged stay in the intensive care unit, where she was mechanically ventilated, developed deep venous thrombosis of the left upper limb and required tracheostomy on account of prolonged endotracheal intubation. Patient recovered fully following bromocriptine and dantrolene therapy. She was discharged home after 60 days on admission and has remained in good health.Conclusion: Though rare, neuroleptic malignant syndrome can occur in young adult females following use of antipsychotics, anaesthesia and surgery. Its clinical course can be prolonged and distressing with the use of depot preparations. Early diagnosis and prompt supportive measures are essential to reduce morbidity and mortality.Keywords: Neuroleptic malignant syndrome, adult female, University of Benin Teaching Hospital

The Waterloo Earth Sciences Museum

The University of Waterloo’s Earth Sciences Museum was started as a Canadian centennial project and has been part of the Department of Earth and Environmental Sciences outreach program for over 40 years. Museum initiatives include lectures; hands-on geological activities such as gold panning; construction of a rock garden; production of geology-themed books for children and adults; podcasts; and participation in gem shows, groundwater festivals and other public events. The museum benefits from public and private funding and the donation of specimens. Volunteers and co-op students allow it to function with a minimum of staff. It provides examples of the types of programs to increase public geological knowledge and understanding that can be offered by even a modest museum. SOMMAIRE Le Musée des Sciences de la Terre à l’Université de Waterloo était un porjet du centennaire duCanada, et depuis a fait parti d’un programme de communication du Département des Sciences de la Terre. Les initiatives incluent des conférences; des activitiés géologiques, comme le lavage de gravier pour séparer de l’or; le développement d’un jardin de rocaille; la production de livres à thèmes géologiques pour enfants et adultes; des programmes pour iPod; et la participation à des exhibitions de pierres précieuses, des festivals de l’eau souterraine et auters activites publiques. Le musée jouit de financement publique et privé, et de dons spécimens. Des bénévoles et des étudiants permettent le fonetionnement avec le minimum d’employés. Ceci offert des exemples de programmes pour améliorer les connaissances st la compréhension de la géologie pour le grand publique qu’un musée de taille modeste peut amener

Light emission from silicon with tin-containing nanocrystals

Tin-containing nanocrystals, embedded in silicon, have been fabricated by growing an epitaxial layer of Si_{1-x-y}Sn_{x}C_{y}, where x = 1.6 % and y = 0.04 %, followed by annealing at various temperatures ranging from 650 to 900 degrees C. The nanocrystal density and average diameters are determined by scanning transmission-electron microscopy to ~ 10^{17} cm^{-3} and ~ 5 nm, respectively. Photoluminescence spectroscopy demonstrates that the light emission is very pronounced for samples annealed at 725 degrees C, and Rutherford back-scattering spectrometry shows that the nanocrystals are predominantly in the diamond-structured phase at this particular annealing temperature. The origin of the light emission is discussed.Comment: 5 pages, 3 figures, submitted to AIP Advance

Not Alone: Tracing the Origins of Very Low Mass Stars and Brown Dwarfs Through Multiplicity Studies

The properties of multiple stellar systems have long provided important empirical constraints for star formation theories, enabling (along with several other lines of evidence) a concrete, qualitative picture of the birth and early evolution of normal stars. At very low masses (VLM; M <~ 0.1 M_sun), down to and below the hydrogen burning minimum mass, our understanding of formation processes is not as clear, with several competing theories now under consideration. One means of testing these theories is through the empirical characterization of VLM multiple systems. Here, we review the results of various VLM multiplicity studies to date. These systems can be generally characterized as closely separated (93% have projected separations Delta < 20 AU) and near equal-mass (77% have M_2/M_1 >= 0.8) occurring infrequently (perhaps 10-30%). Both the frequency and maximum separation of stellar and brown dwarf binaries steadily decrease for lower system masses, suggesting that VLM binary formation and/or evolution may be a mass-dependent process. There is evidence for a fairly rapid decline in the number of loosely-bound systems below ~0.3 M_sun, corresponding to a factor of 10-20 increase in the minimum binding energy of VLM binaries as compared to more massive stellar binaries. This wide-separation ``desert'' is present among both field (~1-5 Gyr) and older (> 100 Myr) cluster systems, while the youngest (<~10 Myr) VLM binaries, particularly those in nearby, low-density star forming regions, appear to have somewhat different systemic properties. We compare these empirical trends to predictions laid out by current formation theories, and outline future observational studies needed to probe the full parameter space of the lowest mass multiple systems.Comment: 16 pages, 7 figures, contributed chapter for Planets and Protostars V meeting (October 2005); full table of VLM binaries can be obtained at http://paperclip.as.arizona.edu/~nsiegler/VLM_binarie