An empirical approach to modeling ion production rates in Titan's ionosphere II: Ion production rates on the nightside

Ionization of neutrals by precipitating electrons and ions is the main source of Titan's nightside ionosphere. This paper has two goals: (1) characterization of the role of electron impact ionization on the nightside ionosphere for different magnetospheric conditions and (2) presentation of empirical ion production rates determined using densities measured by the Cassini Ion and Neutral Mass Spectrometer on the nightside. The ionosphere between 1000 and 1400 km is emphasized. We adopt electron fluxes measured by the Cassini Plasma Spectrometer-Electron Spectrometer and the Magnetospheric Imaging Instrument as classified by Rymer et al. (2009). The current paper follows an earlier paper (Paper I), in which we investigated sources of Titan's dayside ionosphere and demonstrated that the photoionization process is well understood. The current paper (Paper II) demonstrates that modeled and empirical ionization rates on the nightside are in agreement with an electron precipitation source above 1100 km. Ion production rate profiles appropriate for different Saturnian magnetospheric conditions, as outlined by Rymer et al., are constructed for various magnetic field topologies. Empirical production rate profiles are generated for deep nightside flybys of Titan. The results also suggest that at lower altitudes (below 1100 km) another source, such as ion precipitation, is probably needed

An empirical approach to modeling ion production rates in Titan’s ionosphere I: Ion production rates on the dayside and globally

Titan's ionosphere is created when solar photons, energetic magnetospheric electrons or ions, and cosmic rays ionize the neutral atmosphere. Electron densities generated by current theoretical models are much larger than densities measured by instruments on board the Cassini orbiter. This model density overabundance must result either from overproduction or from insufficient loss of ions. This is the first of two papers that examines ion production rates in Titan's ionosphere, for the dayside and nightside ionosphere, respectively. The first (current) paper focuses on dayside ion production rates which are computed using solar ionization sources (photoionization and electron impact ionization by photoelectrons) between 1000 and 1400 km. In addition to theoretical ion production rates, empirical ion production rates are derived from CH4, CH3+, and CH4+ densities measured by the INMS (Ion Neutral Mass Spectrometer) for many Titan passes. The modeled and empirical production rate profiles from measured densities of N2+ and CH4+ are found to be in good agreement (to within 20%) for solar zenith angles between 15 and 90°. This suggests that the overabundance of electrons in theoretical models of Titan's dayside ionosphere is not due to overproduction but to insufficient ion losses

A case of SARS-CoV-2 reinfection in a patient with obstructive sleep apnea managed with telemedicine

The novel coronavirus (SARS-CoV-2) has produced millions of infections and deaths worldwide. It is believed that adaptive immunity to the virus occurs although with variation in its pattern and duration. While uncommon, confirmed reinfection with the novel coronavirus has been reported. Telemedicine has emerged as a viable tool for the delivery of healthcare in lieu of in-person patient contact. The variable and occasionally rapid course of clinical disease raises safety concerns of using telemedicine in the clinical management of acute infection with the novel coronavirus. We present a case of novel coronavirus infection in an immunocompetent individual with obstructive sleep apnea (OSA) who failed to manifest an adaptive immune response to acute infection and was subsequently reinfected. The case highlights the use of telemedicine in managing novel coronavirus respiratory disease and the potential role of OSA as a disease facilitator

Spatial and temporal country-wide survey of temephos resistance in Brazilian populations of Aedes aegypti

Submitted by sandra infurna ([email protected]) on 2016-05-09T13:55:27Z No. of bitstreams: 1 josebento_lima_etal_IOC_2016.pdf: 3016326 bytes, checksum: a6148d98d32d86fcebe6ab5019abf77b (MD5)Approved for entry into archive by sandra infurna ([email protected]) on 2016-05-09T14:13:45Z (GMT) No. of bitstreams: 1 josebento_lima_etal_IOC_2016.pdf: 3016326 bytes, checksum: a6148d98d32d86fcebe6ab5019abf77b (MD5)Made available in DSpace on 2016-05-09T14:13:45Z (GMT). No. of bitstreams: 1 josebento_lima_etal_IOC_2016.pdf: 3016326 bytes, checksum: a6148d98d32d86fcebe6ab5019abf77b (MD5) Previous issue date: 2016Universidade Federal de Viçosa. Departamento de Entomologia. Viçosa, MG, Brasil.Secretaria Municipal de Saúde de Belo Horizonte. Belo Horizonte, MG, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Coordenação Geral do Programa Nacional de Controle da Dengue. Brasília, DF, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Coordenação Geral do Programa Nacional de Controle da Dengue. Brasília, DF, Brasil / Secretaria Municipal de Saúde de São Domingos do Prata. São Domingos do Prata, MG, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Fisiologia e Controle de Artrópodes Vetores. Rio de Janeiro, RJ, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Coordenação Geral de Laboratórios de Saúde Pública. Brasília, DF, Brasil.Secretaria de Saúde do Ceará. Núcleo de Controle de Vetores. Laboratório de Entomologia. Fortaleza, CE, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas Aggeu Magalhães. Recife, PE, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas Aggeu Magalhães. Recife, PE, Brasil.Secretaria de Saúde de São Paulo. Superintendência de Controle de Endemias. Marília, SP, Brasil.Secretaria de Saúde do Ceará. Núcleo de Controle de Vetores. Laboratório de Entomologia. Fortaleza, CE, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Coordenação Geral do Programa Nacional de Controle da Dengue. Brasília, DF, Brasil.Universidade Federal de Viçosa. Departamento de Entomologia. Viçosa, MG, Brasil.The organophosphate temephos has been the main insecticide used against larvae of the dengue and yellow fever mosquito (Aedes aegypti) in Brazil since the mid-1980s. Reports of resistance date back to 1995; however, no systematic reports of widespread temephos resistance have occurred to date. As resistance investigation is paramount for strategic decision-making by health officials, our objective here was to investigate the spatial and temporal spread of temephos resistance in Ae. aegypti in Brazil for the last 12 years using discriminating temephos concentrations and the bioassay protocols of the World Health Organization. The mortality results obtained were subjected to spatial analysis for distance interpolation using semi-variance models to generate maps that depict the spread of temephos resistance in Brazil since 1999. The problem has been expanding. Since 2002-2003, approximately half the country has exhibited mosquito populations resistant to temephos. The frequency of temephos resistance and, likely, control failures, which start when the insecticide mortality level drops below 80%, has increased even further since 2004. Few parts of Brazil are able to achieve the target 80% efficacy threshold by 2010/2011, resulting in a significant risk of control failure by temephos in most of the country. The widespread resistance to temephos in Brazilian Ae. aegypti populations greatly compromise effective mosquito control efforts using this insecticide and indicates the urgent need to identify alternative insecticides aided by the preventive elimination of potential mosquito breeding sites