Quantum discord in spin-cluster materials

The total quantum correlation (discord) in Heisenberg dimers is expressed via the spin-spin correlation function, internal energy, specific heat or magnetic susceptibility. This allows one to indirectly measure the discord through neutron scattering, as well as calorimetric or magnetometric experiments. Using the available experimental data, we found the discord for a number of binuclear Heisenberg substances with both antiferro- and ferromagnetic interactions. For the dimerized antiferromagnet copper nitrate Cu(NO_3)_2*2.5H_2O, the three independent experimental methods named above lead to a discord of approximately 0.2-0.3 bit/dimer at a temperature of 4 K. We also determined the temperature behavior of discord for hydrated and anhydrous copper acetates, as well as for the ferromagnetic binuclear copper acetate complex [Cu_2L(OAc)]*6H_2O, where L is a ligand.Comment: 7 pages, 6 figure

Cavity-enhanced optical Hall effect in two-dimensional free charge carrier gases detected at terahertz frequencies

The effect of a tunable, externally coupled Fabry-P\'{e}rot cavity to resonantly enhance the optical Hall effect signatures at terahertz frequencies produced by a traditional Drude-like two-dimensional electron gas is shown and discussed in this communication. As a result, the detection of optical Hall effect signatures at conveniently obtainable magnetic fields, for example by neodymium permanent magnets, is demonstrated. An AlInN/GaN-based high electron mobility transistor structure grown on a sapphire substrate is used for the experiment. The optical Hall effect signatures and their dispersions, which are governed by the frequency and the reflectance minima and maxima of the externally coupled Fabry-P\'{e}rot cavity, are presented and discussed. Tuning the externally coupled Fabry-P\'{e}rot cavity strongly modifies the optical Hall effect signatures, which provides a new degree of freedom for optical Hall effect experiments in addition to frequency, angle of incidence and magnetic field direction and strength

Flint glass bottles cause white wine aroma identity degradation

Due to marketing recommendations, white wines are often bottled in flint glass to improve aesthetics and showcase wine color. Although this practice is known to cause a wine fault, the influence of light on the fruity and flowery aromatic profile of wine is unknown. The aim of this study was to investigate the changes to the white wine volatilome under typical supermarket shelf conditions, using 1,052 bottles of 24 white wines. After only 7 d of shelf life in flint glass bottles, a dramatic loss in terpenes (10 to 30%) and norisoprenoids (30 to 70%) was recorded, whereas colored glass bottles did not evidence such behavior even after 50 d, and darkness preserved the wine’s fruity and flowery aromatic integrity. We also proposed an alternative mechanism for the insurgence of the lightstrike off-odor, which takes the varietal aroma loss into account. In light of this understanding of the flint glass negative impact on white wine aroma identity and sensorial character, this packaging should be strongly discouraged. The same findings should be valid for a wide range of several daily consumed foodstuff where transparent packaging is use

Fístula colovesical secundaria a enfermedad diverticular: cirugía laparoscópica electiva

Indexación: Web of Science; ScieloAim: Colovesical fistula is a severe complication associated to neoplastic or inflammatory colon disease. Most common procedure is open surgery. We report a case of colovesical fistula secondary to diverticular disease treated with a laparoscopic approach. Methods: A 64-year-old man was seen with a known colonic diverticular disease, type 2 diabetes mellitus and recurrent urinary tract infection. He complained of lower abdominal pain, dysuria, and pneumaturia. A CT scan revealed a sigmoid diverticular perforation into the bladder (colovesical fistula). A left hemicolectomy with partial cystectomy was performed by laparoscopy means. Results: There was no morbidity related to the surgical procedure, and the final pathology confirmed a colonic diverticular disease with bladder compromise. The patient is asymptomatic at 24 months of follow up. Conclusion: The laparoscopic approach is a feasible alternative for the treatment of colovesical fistula with low morbidity.Objetivos: La fístula colovesical es una complicación relacionada con procesos inflamatorios y neoplá-sicos del colon. El manejo tradicional de esta patología es quirúrgico bajo técnica abierta. Presentamos un caso de fístula colovesical secundaria a enfermedad diverticular con tratamiento quirúrgico laparoscópico. Materiales y Métodos: Paciente masculino de 64 años de edad, portador de enfermedad diverticular de larga data con antecedente de diabetes mellitus tipo 2 e infecciones urinarias a repetición, quien consulta por presentar dolor en hipogastrio, disuria y neumaturia. Se realiza tomografía computada que revela perforación diverticular de colon sigmoides a vejiga (fístula colovesical). Se realizó hemicolectomía izquierda más cistectomía parcial, con resección del trayecto fistuloso, y cierre vesical y anastomosis colónica laparoscópica. Resultados: No hubo complicaciones intra ni postoperatorias. El estudio anatomopatológico de la pieza operatoria demostró enfermedad diverticular. El paciente se encuentra asintomático a los 24 meses de seguimiento. Conclusión: El abordaje laparoscópico es una alternativa factible para el tratamiento de fístula colovesical, con baja morbilidad.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-40262012000300010&nrm=is

Diversity Climate Survey Results: Changing Institutional Culture

Purpose: To gather and analyze data at two points in time on perceptions of institutional values connected to a wide range of diversity issues. This study gauges student, faculty, and staff views on institutional support of diversity with results guiding future inclusion and training efforts within the organization. Presented at the AAMC (Association of American Colleges) Annual Meeting, RIME (Research in Medical Education) Program, November 2008