Photo-induced second-order nonlinearity in stoichiometric silicon nitride waveguides

We report the observation of second-harmonic generation in stoichiometric silicon nitride waveguides grown via low-pressure chemical vapour deposition. Quasi-rectangular waveguides with a large cross section were used, with a height of 1 {\mu}m and various different widths, from 0.6 to 1.2 {\mu}m, and with various lengths from 22 to 74 mm. Using a mode-locked laser delivering 6-ps pulses at 1064 nm wavelength with a repetition rate of 20 MHz, 15% of the incoming power was coupled through the waveguide, making maximum average powers of up to 15 mW available in the waveguide. Second-harmonic output was observed with a delay of minutes to several hours after the initial turn-on of pump radiation, showing a fast growth rate between 10$^{-4}$ to 10$^{-2}$ s$^{-1}$, with the shortest delay and highest growth rate at the highest input power. After this first, initial build-up, the second-harmonic became generated instantly with each new turn-on of the pump laser power. Phase matching was found to be present independent of the used waveguide width, although the latter changes the fundamental and second-harmonic phase velocities. We address the presence of a second-order nonlinearity and phase matching, involving an initial, power-dependent build-up, to the coherent photogalvanic effect. The effect, via the third-order nonlinearity and multiphoton absorption leads to a spatially patterned charge separation, which generates a spatially periodic, semi-permanent, DC-field-induced second-order susceptibility with a period that is appropriate for quasi-phase matching. The maximum measured second-harmonic conversion efficiency amounts to 0.4% in a waveguide with 0.9 x 1 {\mu}m$^2$ cross section and 36 mm length, corresponding to 53 {\mu}W at 532 nm with 13 mW of IR input coupled into the waveguide. The according $\chi^{(2)}$ amounts to 3.7 pm/V, as retrieved from the measured conversion efficiency.Comment: 20 pages, 10 figure

Scientific Opinion on peste des petits ruminants

Peste des petits ruminants (PPR) is a severe viral disease of small ruminants caused by a Morbillivirus closely related to rinderpest virus. It is widespread in Africa and Asia and is currently also found in Turkey and Northern Africa. PPR is transmitted via direct contact, and the disease would mainly be transferred to infection-free areas by transport of infected animals. In the EU, it could only happen through illegal transport of animals. The risk of that depends on the prevalence in the country of origin and the number of animals illegally moved. The extent of the spread would depend mainly on the time during which it is undetected, the farm density, the frequency and distance of travel of animals. PPR has a high within-herd transmission rate, therefore contacts between flocks, e.g. through common grazing areas, should be avoided when PPR is present. If PPR enters EU areas with dense sheep population but low goat density, it may spread rapidly undetected, since goats are considered more susceptible than sheep. Effective measures in limiting the spread of PPR in the EU include prompt culling of infected herds, rapid detection, movement restriction, and disinfection. Live attenuated vaccines against PPR are available, safe and effective, and have been successfully used to control PPR epidemics, but no method exists for differentiating between infected and vaccinated animals; therefore, the development of one is recommended. Awareness-raising campaigns for farmers and veterinary staff to promote recognition of the disease should be considered. The cooperation of the EU with neighbouring countries should be encouraged to prevent the spread 20 of PPR and other transboundary diseases

Scientific Opinion on lumpy skin disease

Lumpy skin disease (LSD) is a viral disease of cattle characterised by severe losses, especially in naive animals. LSD is endemic in many African and Asian countries, and it is rapidly spreading throughout the Middle East, including Turkey. LSD is transmitted by mechanical vectors, but direct/indirect transmission may occur. The disease would mainly be transferred to infection-free areas by transport of infected animals and vectors. In the EU, it could only happen through illegal transport of animals. The risk for that depends on the prevalence in the country of origin and the number of animals illegally moved. Based on a model to simulate LSD spread between farms, culling animals with generalised clinical signs seems to be sufficient to contain 90 % of epidemics around the initial site of incursion, but the remaining 10 % of simulated epidemics can spread up to 400 km from the site of introduction by six months after incursion. Whole-herd culling of infected farms substantially reduces the spread of LSD virus, and the more rapidly farms are detected and culled, the greater the magnitude of the reduction is. Only live attenuated vaccines against LSD are available. Homologous vaccines are more effective than sheep pox strain vaccines. The safety of the vaccines should be improved and the development of vaccines for differentiating between infected and vaccinated animals is recommended. Epidemics are not self-limiting when effective vaccination or culling are not applied. Active surveillance, rapid detection and prompt culling of infected herds are effective measures for LSD control. The role of vectors for LSD transmission should be further investigated in both controlled environments and the field. Awareness-raising campaigns for farmers and veterinary staff to promote recognition of LSD should be considered. The cooperation of the EU with neighbouring countries should be encouraged to prevent transboundary disease spread.info:eu-repo/semantics/publishedVersio

Assessing the health status of managed honeybee colonies (HEALTHY-B): a toolbox to facilitate harmonised data collection

Tools are provided to assess the health status of managed honeybee colonies by facilitating further harmonisation of data collection and reporting, design of field surveys across the European Union (EU) and analysis of data on bee health. The toolbox is based on characteristics of a healthy managed honeybee colony: an adequate size, demographic structure and behaviour; an adequate production of bee products (both in relation to the annual life cycle of the colony and the geographical location); and provision of pollination services. The attributes ‘queen presence and performance’, ‘demography of the colony’, ‘in-hive products’ and ‘disease, infection and infestation’ could be directly measured in field conditions across the EU, whereas ‘behaviour and physiology’ is mainly assessed through experimental studies. Analysing the resource providing unit, in particular land cover/use, of a honeybee colony is very important when assessing its health status, but tools are currently lacking that could be used at apiary level in field surveys across the EU. Data on ‘beekeeping management practices’ and ‘environmental drivers’ can be collected via questionnaires and available databases, respectively. The capacity to provide pollination services is regarded as an indication of a healthy colony, but it is assessed only in relation to the provision of honey because technical limitations hamper the assessment of pollination as regulating service (e.g. to pollinate wild plants) in field surveys across the EU. Integrating multiple attributes of honeybee health, for instance, via a Health Status Index, is required to support a holistic assessment. Examples are provided on how the toolbox could be used by different stakeholders. Continued interaction between the Member State organisations, the EU Reference Laboratory and EFSA is required to further validate methods and facilitate the efficient use of precise and accurate bee health data that are collected by many initiatives throughout the EU.info:eu-repo/semantics/publishedVersio

Urgent advice on lumpy skin disease EFSA Panel on Animal Health and Welfare

In order to assess the effects on disease spread and persistence of partial stamping out of only clinically affected animals in holdings where the presence of lumpy skin disease has been confirmed, against total stamping-out policy of infected herds coupled with vaccination, a mathematical model for the transmission of LSDV between farms was developed and different scenarios explored. According to the model, vaccination has a greater impact in reducing LSDV spread than any culling policy, even when low vaccination effectiveness is considered. When vaccination is evenly applied so that 95% of the farms are vaccinated with 75% of vaccinated animals effectively protected, then total stamping out and partial stamping out result in a similar probability of eradicating the infection. When no vaccination is applied or when vaccination has a lower effectiveness (e.g. 40%), the probability of eradication is higher when total stamping out is performed as compared to partial stamping out. In general, partial stamping out results in limited increase of the number of farms affected as compared to total stamping out. Independently of the culling interventions applied in the model, vaccination was most effective in reducing LSDV spread if protection had already been developed at the time of virus entry, followed by protection of herds after virus entry. No vaccination is the least effective option in reducing LSDV spread. In order to reach the above described effects, it is necessary to implement vaccination of the entire susceptible population in regions at risk for LSDV introduction or affected by LSDV in order to minimise the number of outbreaks, and high animal- and farm-level vaccination coverage should be achieved. Farmers and veterinarians should be trained in the clinical identification of LSD in order to reduce underreporting, and the effectiveness of partial stamping out should be evaluated under field conditions.info:eu-repo/semantics/publishedVersio

Guidance on the assessment criteria for applications for new or modified stunning methods regarding animal protection at the time of killing

This guidance defines the process for handling applications on new or modified stunning methods and the parameters that will be assessed by the EFSA Animal Health and Welfare (AHAW) Panel. The applications, received through the European Commission, should contain administrative information, a checklist of data to be submitted and a technical dossier. The dossier should include two or more studies (in laboratory and slaughterhouse conditions) reporting all parameters and methodological aspects that are indicated in the guidance. The applications will first be scrutinised by the EFSA’s Applications Desk (APDESK) Unit for verification of the completeness of the data submitted for the risk assessment of the stunning method. If the application is considered not valid, additional information may be requested from the applicant. If considered valid, it will be subjected to assessment phase 1 where the data related to parameters for the scientific evaluation of the stunning method will be examined by the AHAW Panel. Such parameters focus on the stunning method and the outcomes of interest, i.e. immediate onset of unconsciousness or the absence of avoidable pain, distress and suffering until the loss of consciousness and duration of the unconsciousness (until death). The applicant should also propose methodologies and results to assess the equivalence with existing stunning methods in terms of welfare outcomes. Applications passing assessment phase 1 will be subjected to the following phase 2 which will be carried out by the AHAW Panel and focuses on the animal welfare risk assessment. In this phase, the Panel will assess the outcomes, conclusions and discussion proposed by the applicant. The results of the assessment will be published in a scientific opinion.info:eu-repo/semantics/publishedVersio

Guidance on the assessment criteria for applications for new or modified stunning methods regarding animal protection at the time of killing

This guidance defines the process for handling applications on new or modified stunning methods and the parameters that will be assessed by the EFSA Animal Health and Welfare (AHAW) Panel. The applications, received through the European Commission, should contain administrative information, a checklist of data to be submitted and a technical dossier. The dossier should include two or more studies (in laboratory and slaughterhouse conditions) reporting all parameters and methodological aspects that are indicated in the guidance. The applications will first be scrutinised by the EFSA’s Applications Desk (APDESK) Unit for verification of the completeness of the data submitted for the risk assessment of the stunning method. If the application is considered not valid, additional information may be requested from the applicant. If considered valid, it will be subjected to assessment phase 1 where the data related to parameters for the scientific evaluation of the stunning method will be examined by the AHAW Panel. Such parameters focus on the stunning method and the outcomes of interest, i.e. immediate onset of unconsciousness or the absence of avoidable pain, distress and suffering until the loss of consciousness and duration of the unconsciousness (until death). The applicant should also propose methodologies and results to assess the equivalence with existing stunning methods in terms of welfare outcomes. Applications passing assessment phase 1 will be subjected to the following phase 2 which will be carried out by the AHAW Panel and focuses on the animal welfare risk assessment. In this phase, the Panel will assess the outcomes, conclusions and discussion proposed by the applicant. The results of the assessment will be published in a scientific opinion.info:eu-repo/semantics/publishedVersio

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429):porcine reproductive and respiratory syndrome (PRRS)

Abstract Porcine reproductive and respiratory syndrome (PRRS) has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on the eligibility of PRRS to be listed, Article 9 for the categorisation of PRRS according to disease prevention and control rules as in Annex IV and Article 8 on the list of animal species related to PRRS. The assessment has been performed following a methodology composed of information collection and compilation, expert judgement on each criterion at individual and, if no consensus was reached before, also at collective level. The output is composed of the categorical answer, and for the questions where no consensus was reached, the different supporting views are reported. Details on the methodology used for this assessment are explained in a separate opinion. According to the assessment performed, PRRS can be considered eligible to be listed for Union intervention as laid down in Article 5(3) of the AHL. The disease would comply with the criteria as in Sections 4 and 5 of Annex IV of the AHL, for the application of the disease prevention and control rules referred to in points (d) and (e) of Article 9(1). The animal species to be listed for PRRS according to Article 8(3) criteria are domestic pigs and wild boar