Full polarization control for fiber optical quantum communication systems using polarization encoding

A real-time polarization control system employing two nonorthogonal reference signals multiplexed in either time or wavelength with the data signal is presented. It is shown, theoretically and experimentally, that complete control of multiple polarization states can be attained employing polarization controllers in closed-loop configuration. Experimental results show that negligible added penalties, corresponding to an average added optical Quantum Bit Error Rate of 0.044%, can be achieved with response times smaller than 10 ms, without significant introduction of noise counts in the quantum channel.Comment: 6 pages, 5 figures. Submitted to Optics Expres

Experimental polarization encoded quantum key distribution over optical fibres with real-time continuous birefringence compensation

In this paper we demonstrate an active polarization drift compensation scheme for optical fibres employed in a quantum key distribution experiment with polarization encoded qubits. The quantum signals are wavelength multiplexed in one fibre along with two classical optical side channels that provide the control information for the polarization compensation scheme. This set-up allows us to continuously track any polarization change without the need to interrupt the key exchange. The results obtained show that fast polarization rotations of the order of 40*pi rad/s are effectively compensated for. We demonstrate that our set-up allows continuous quantum key distribution even in a fibre stressed by random polarization fluctuations. Our results pave the way for Bell-state measurements using only linear optics with parties separated by long-distance optical fibres

Clinical trials field strategies with novel vaccines produced in Brazil

OBJECTIVE: To report field strategies applied to clinical trials with vaccines developed by Instituto Butantan in Campinas, Brazil, in 2004 and 2006. METHODS: This report describes the planning and the operational issues of two clinical trials conducted to evaluate immunogenicity and safety of recombinant Hepatitis B vaccine combined with BCG vaccine (BCG/VrHB-IB) and quadrivalent diphteria-tetanus-Haemophilus influenzae type b-cellular pertussis vaccine with low lipopolysaccharide (DTPm/Hib). RESULTS: The main field strategies applied were: a) Partnership between the researchers and managers from Municipal Health Department and b) Research procedures at home or in Health Centers attended by participants. In the first study, BCG vaccine and VrHB-IB (combined or separated) were given to 552 newborns in the maternity, followed by two subsequent doses of VrHB-IB vaccine in households. The second study included 241 infants at Health Centers, which were vaccinated with DTPm/Hib vaccines concomitantly to the others recommended by the National Immunization Program. In both studies, blood samples were taken at home. No adverse events occurred during the experimental period. The field strategies used in those clinical trials allowed adherence by 90.2 and 93.8% of the participants of the first and second study, respectively. The vaccines were given according to the recommendation of National Immunization Program and blood samples were obtained according to the protocol schedules. CONCLUSIONS: The field strategies were important to guarantee enrollment and protocol compliance, causing little interference in families' daily routine, pediatrics appointments and children's vaccine.OBJETIVO: Relatar as estratégias de campo utilizadas em dois ensaios clínicos com vacinas desenvolvidas pelo Instituto Butantan, em 2004 e 2006. MÉTODOS: Estudo do tipo relato de experiência, em que se descreve o planejamento e a operacionalização dos ensaios clínicos, que avaliaram a imunogenicidade e a segurança da vacina BCG combinada com a vacina da hepatite B (VrHB-IB) e da tetravalente bacteriana modificada pela extração do lipopolissacarídeo (LPS) do componente pertussis (DTPm/Hib). RESULTADOS: As principais estratégias de campo utilizadas foram: a) Parceria entre os pesquisadores e os gestores da Secretaria Municipal de Saúde e b) Realização dos procedimentos da pesquisa nos domicílios ou nos Centros de Saúde frequentados pelos participantes. No primeiro estudo, foram vacinados 552 recém-nascidos na maternidade com a BCG/VrHB-IB (combinadas ou separadas) e nos domicílios, com as duas doses subsequentes de VrHB-IB. O segundo estudo incluiu 241 lactentes em Centros de Saúde da rede municipal, vacinados com tetravalente bacteriana (com componente pertussis total ou modificado). Em ambos os estudos, amostras de sangue foram colhidas nas residências. Não houve relatos de eventos adversos. A adesão foi de 90,2% para o primeiro estudo e 93,8%, para o segundo. As vacinas foram administradas nas datas preconizadas pelo Programa Nacional de Imunizações e as coletas de sangue, de acordo com o cronograma dos estudos. CONCLUSÕES: As estratégias utilizadas facilitaram o recrutamento das crianças e garantiram cumprir o protocolo da pesquisa com alta adesão, sem interferir no vínculo da família com o Serviço de Saúde, no calendário vacinal ou no seguimento pediátrico dos participantes.OBJETIVO: Relatar las estrategias de campo utilizadas en dos ensayos clínicos con vacunas desarrolladas por el Instituto Butantan, en 2004 y 2006. MÉTODOS: Estudio de tipo relato de experiencia, en que se describe la planificación y la operacionalización de los ensayos clínicos, que evaluaron la imunogenicidad y la seguridad de la vacuna BCG combinada con la vacuna de la hepatitis B (VrHB-IB) y de la tetravalente bacteriana modificada por la extracción del lipopolisacárido (LPS) y del componente pertussis (DPTm/Hib). RESULTADOS: Las principales estrategias de campo utilizadas fueron: a) Colaboración entre los investigadores y los gestores de la Secretaría Municipal de Salud y b) Realización de los procedimientos de la investigación en los domicilios o Centros de Salud frecuentados por los participantes. En el primero estudio, se vacunaron 552 recién nacidos en la maternidad con la BCG/VrHB-IB (combinadas o separadas), y en los domicilios, con las dos dosis subsiguientes de VrHB-IB. El segundo estudio incluyó a 241 lactantes en Centros de Salud de la red municipal, vacunados con tetravalente bacteriana (con componente pertussis total o modificado). En ambos estudios, muestras de sangre fueron recogidas en las residencias. No hubo relato de eventos adversos. La adhesión fue de 90,2% para el primero estudio y de 93,8% para el segundo. Las vacunas fueron administradas en las fechas preconizadas por el Programa Nacional de Inmunizaciones y las muestras de sangre fueron recogidas conforme al cronograma de estudios. CONCLUSIONES: Las estrategias utilizadas facilitaron el reclutamiento de los niños y garantizaron cumplir con el protocolo de la investigación con alta adhesión, sin interferir en el vínculo de la familia con el Servicio de Salud, en el calendario de vacunas o en el seguimiento pediátrico de los participantes.20220

New spectral index and machine learning models for detecting coffee leaf miner infestation using sentinel-2 multispectral imagery.

The coffee leaf miner (Leucoptera coffeella) is a key coffee pest in Brazil that can cause severe defoliation and a negative impact on the productivity. Thus, it is essential to identify initial pest infestation for the sake of appropriate time control to avoid further economic damage to the coffee crops. A fast non-destructive method is an important tool that can be used to monitor the occurrence of the coffee leaf miner. The present work aims to identify the occurrence of coffee leaf miner infestation through a new vegetation index, using multispectral images from the Sentinel-2 satellite and the Google Earth Engine platform. Coffee leaf miner infestation was measured in the field in four cities in the state of Minas Gerais. The largest infestations occurred in September, October, and November but particularly in October 2021, in which the rate of infestation reached 85%, followed by September 2020 with a maximum infestation of 76%. The calculation steps of the vegetation indices and mappings were carried out in the Google Earth Engine cloud processing platform through the development of a script in JavaScript programming language. Combinations of two sensitive bands were selected to detect coffee leaf miner infestation, and from these, the 'Coffee-Leaf-Miner Index' was developed, which was compared with other existing vegetation indices in terms of their performance for coffee leaf miner detection. The combination of the NIR-BLUE and NIR-RED bands was more sensitive for the detection of coffee leaf miner infestation; therefore, the NIR, BLUE, and RED bands were selected to develop the new index. The 'Coffee-Leaf-Miner Index' presented the best performance among those evaluated, with a coefficient of determination of about 0.87, a root mean square error of 4.92% coffee leaf miner infestation, accuracy of 89.47%, and kappa coefficient of 95.39. The R2 range of other spectral indices which exist in the literature and which were used in this study was from 0.017 to 0.867, and the root mean square error ranged from 4.996 to 13.582% coffee leaf miner infestation. The machine learning method was then adopted using the supervised Random Forest and Support Vector Machine algorithms to recognize patterns of coffee leaf miner infestation in the field, only the Coffee-Leaf-Miner Index was used for the identification test of the coffee leaf miner infestation. The Support Vector Machine with linear Kernel type was applied to establish a discrimination model. The number of trees for the Random Forest classifier was 100. The Support Vector Machine presented a lower performance than the Random Forest algorithm, but the performance of both were above 80% for user and producer precision. Three bands (Blue, Red, NIR) were selected for the creation of the new index, which showed capacity for remote detection of coffee leaf miner infestation on a regional scale. Thus, 'Coffee-Leaf-Miner Index' can identify coffee leaf miner infestation thanks to all the complexity involved in detecting pests via orbital remote sensing