Transmission Of Optical Coherent State Qubits

We discuss the long distance transmission of qubits encoded in optical coherent states. Through absorption these qubits suffer from two main types of errors, the reduction of the amplitude of the coherent states and accidental application of the Pauli Z operator. We show how these errors can be fixed using techniques of teleportation and error correcting codes.Comment: Added two pages of explanation/background/review material to increase readability and clarity. Corrected minor typographical and linguistic error

Entanglement Purification of Any Stabilizer State

We present a method for multipartite entanglement purification of any stabilizer state shared by several parties. In our protocol each party measures the stabilizer operators of a quantum error-correcting code on his or her qubits. The parties exchange their measurement results, detect or correct errors, and decode the desired purified state. We give sufficient conditions on the stabilizer codes that may be used in this procedure and find that Steane's seven-qubit code is the smallest error-correcting code sufficient to purify any stabilizer state. An error-detecting code that encodes two qubits in six can also be used to purify any stabilizer state. We further specify which classes of stabilizer codes can purify which classes of stabilizer states.Comment: 11 pages, 0 figures, comments welcome, submitting to Physical Review

Influência da sazonalidade na infestação de Ergasilus turucuyus (Copepoda: Ergasilidae) em Acestrorhynchus falcirostris e Hemiodus unimaculatus (Osteichthyes: Characiformes) do Reservatório Coaracy Nunes, estado do Amapá, Brasil.

O presente estudo investigou a influência da sazonalidade na infestação de Ergasilus turucuyus nas espécies de peixe Acestrorhynchus falcirostris e Hemiodus unimaculatus do Reservatório Coaracy Nunes, Estado do Amapá, Norte do Brasil. Foram coletados 118 espécimes de hospedeiros, sendo 62 A. falcirostris e 56 H. unimaculatus nos períodos de estiagem (outubro de 2012 a fevereiro de 2013) e chuvoso (abril a agosto de 2013) As características físicas e químicas da água foram similares no período chuvoso e de estiagem. Apesar das diferenças nos níveis de precipitação pluviométrica entre períodos sazonais, os níveis de infestação por E. turucuyus foram similares durante a estação chuvosa e estiagem. Não houve infestação por ergasilídeos em H. unimaculatus no período chuvoso. A infestação branquial por E. turucuyus não influenciou o fator de condição de ambos os hospedeiros, independente do período sazonal. Este foi o primeiro estudo sobre sazonalidade de infestação por E. turucuyus

First study on infestation of Excorallana berbicensis (Isopoda: Corallanidae) on six fishes in a reservoir in Brazilian Amazon during dry and rainy seasons.

We analyzed the infestation levels of Excorallana berbicensis on Acestrorhynchus falcirostris, Ageneiosus ucayalensis, Geophagus proximus, Hemiodus unimaculatus, Psectrogaster falcata and Serrasalmus gibbus in a reservoir in the Araguari River basin, northern Brazil, during the dry and rainy seasons. For P. falcata, the infestation levels due to E. berbicensis were greater during the rainy season. For all the species studied, the peak parasite prevalence was in the month of highest rainfall levels and there were two peaks of parasite abundance: one in the month with highest rainfall level and the other in the month of transition from the rainy season to the dry season. In these hosts, around 70% of the E. berbicensis specimens were collected during the rainy season. The body conditions of the hosts also did not suffer any seasonal influence. Despite the differences in seasonal rainfall levels, there was no fluctuation in transparency, turbidity, pH, electric conductivity, temperature and dissolved oxygen levels in the water, due to the stability of these parameters during the seasonal cycle investigated in this artificial Amazon ecosystem. This was the first report on the seasonality of infestation by E. berbicensis associated with fish