Entangling power of quantized chaotic systems

We study the quantum entanglement caused by unitary operators that have classical limits that can range from the near integrable to the completely chaotic. Entanglement in the eigenstates and time-evolving arbitrary states is studied through the von Neumann entropy of the reduced density matrices. We demonstrate that classical chaos can lead to substantially enhanced entanglement. Conversely, entanglement provides a novel and useful characterization of quantum states in higher dimensional chaotic or complex systems. Information about eigenfunction localization is stored in a graded manner in the Schmidt vectors, and the principal Schmidt vectors can be scarred by the projections of classical periodic orbits onto subspaces. The eigenvalues of the reduced density matrices are sensitive to the degree of wavefunction localization, and are roughly exponentially arranged. We also point out the analogy with decoherence, as reduced density matrices corresponding to subsystems of fully chaotic systems are diagonally dominant.Comment: 21 pages including 9 figs. (revtex

A Protocol for a Pan-Canadian Prospective Observational Study on Active Surveillance or Surgery for Very Low Risk Papillary Thyroid Cancer

BackgroundThe traditional management of papillary thyroid cancer (PTC) is thyroidectomy (total or partial removal of the thyroid). Active surveillance (AS) may be considered as an alternative option for small, low risk PTC. AS involves close follow-up (including regularly scheduled clinical and radiological assessments), with the intention of intervening with surgery for disease progression or patient preference.MethodsThis is a protocol for a prospective, observational, long-term follow-up multi-centre Canadian cohort study. Consenting eligible adults with small, low risk PTC (< 2cm in maximal diameter, confined to the thyroid, and not immediately adjacent to critical structures in the neck) are offered the choice of AS or surgery for management of PTC. Patient participants are free to choose either option (AS or surgery) and the disease management course is thus not assigned by the investigators. Surgery is provided as usual care by a surgeon in an institution of the patient’s choice. Our primary objective is to determine the rate of ‘failure’ of disease management in respective AS and surgical arms as defined by: i) AS arm – surgery for progression of PTC, and ii) surgical arm - surgery or other treatment for disease persistence or progression after completing initial treatment. Secondary outcomes include long-term thyroid oncologic and treatment outcomes, as well as patient-reported outcomes.DiscussionThe results from this study will provide long-term clinical and patient reported outcome evidence regarding active surveillance or immediate surgery for management of small, low risk PTC. This will inform future clinical trials in disease management of small, low risk papillary thyroid cancer.Registration detailsThis prospective observational cohort study is registered on clinicaltrials.gov (NCT04624477), but it should not be considered a clinical trial as there is no assigned intervention and patients are free to choose either AS or surgery

Avaliação de programas hormonais para a indução e sincronização do estro em caprinos Evaluation of hormonal programs to induce and synchronize estrus in goats

O objetivo deste trabalho foi estabelecer alternativas para indução e sincronização do estro em cabras leiteiras manejadas semi-intensivamente. Foram conduzidos quatro experimentos com 411 cabras na Embrapa-Centro Nacional de Pesquisa deCaprinos, Sobral, CE. No protocolo básico, utilizaram-se esponjas intra-vaginais com 50 mg de acetato de medroxiprogesterona (MAP) por dez dias e aplicação intra-muscular de 100 mig de cloprostenol e 200 UI de gonadotropina coriônica eqüina (eCG) no 8º dia; a inseminação artificial (IA), com sêmen congelado foi feita 38 horas após remoção da esponja. No experimento1 substituiu-se a e CG pelo "efeito macho"; no experimento 2 substituiu-se a dose de MAP para 60 mg; no experimento3 compararam-se diferentes momentos de IA: 38, 44 e 50 horas e no experimento 4 substituiu-se a eCG pela gonadotropina humana (hCG). Nenhuma das alternativas testadas modificou (P>0,05) a prolificidade. A IA em cio natural gerou maior (P<0,05) índice de parição no experimento2(67,7%) e no experimento 4 (73,3%). A dose de 60 mg de MAP permitiu realizar a IA mais tarde (44 horas apósretirar a esponja) sem detrimento da fertilidade. A hCG equivaleu a eCG, se aplicada 48 horas antes de retirar a esponja.<br>The objective of this study was to establish alternatives to induce and synchronize estrus in dairy goats managed under semi-intensive conditions. Four experiments were carried out using 411 goats at the Embrapa-Centro Nacional de Pesquisa de Caprinos, Sobral, CE, Brazil. In the basic protocol, intra-vaginal sponges were used with 50 mg of medroxyprogesterone acetate (MAP) over ten days, associated with intra-muscular shots of cloprostenol, and equine corionic gonadotropin (eCG) at the 8th day. Artificial insemination (AI) with frozen semen took place 38 hours after sponge withdrawal. In the first experiment, eCG was replaced by "buck effect"; in the second experiment, 60 mg MAP replaced the usual dose; the third experiment compared different pre-fixed time for AI: 38, 44 and 50 hours and in the fourth experiment, hCG (human corionic gonadotropin) given at different moments, replaced eCG. Prolificacy was not influenced (P>0.05) by any changes of basic protocol.After natural estrus, AIprovided higher (P<0.05) parturition rates in the second (67.7%) and fourth experiment (73.3%). Sponge with 60mg MAP allowed to inseminate later (44 hours after removal) without impairing fertility. As long as hCG is given 48 hours before sponge removal it results equals to eCG ones