Plasma treatment of polymer dielectric films to improve capacitive energy storage

Demand for compact instrumentation, portable field equipment, and new electromagnetic weapons is creating a need for new dielectric materials with higher energy storage capabilities. Recognizing the need for higher energy storage capacitors, the Army Research Lab at Fort Monmouth, NJ, initiated a program a year ago to investigate potential methods for increasing the dielectric strength of polyvinylidene difluoride (PVDF) film, which is the highest energy density material commercially available today. Treatment of small area PVDF films in a CF4/O2 plasma showed that the dielectric strength of PVDF films can be increased by as much as 20 percent when treated in a 96 percent CF4/4 percent O2 plasma. This 44 percent increase in energy storage of a PVDF capacitor is significant considering that the treatment can be implemented in a conventional metallizing chamber, with minimum capital investment. The data shows that improved breakdown strength may be unique to PVDF film and the particular CF4/O2 gas mixture, because PVDF film treated with 100 percent CF4, 100 percent O2, Ar gas plasma, and electron irradiation shows no improvement in breakdown strength. Other data presented includes dissipation factor, dielectric constant, and surface tension measurements

Transcriptomic Responses of the Honey Bee Brain to Infection with Deformed Wing Virus

Managed colonies of European honey bees (Apis mellifera) are under threat from Varroa destructor mite infestation and infection with viruses vectored by mites. In particular, deformed wing virus (DWV) is a common viral pathogen infecting honey bees worldwide that has been shown to induce behavioral changes including precocious foraging and reduced associative learning. We investigated how DWV infection of bees affects the transcriptomic response of the brain. The transcriptomes of individual brains were analyzed using RNA-Seq after experimental infection of newly emerged adult bees with DWV. Two analytical methods were used to identify differentially expressed genes from the ~15,000 genes in the Apis mellifera genome. The 269 genes that had increased expression in DWV infected brains included genes involved in innate immunity such as antimicrobial peptides (AMPs), Ago2, and Dicer. Single bee brain NMR metabolomics methodology was developed for this work and indicates that proline is strongly elevated in DWV infected brains, consistent with the increased presence of the AMPs abaecin and apidaecin. The 1361 genes with reduced expression levels includes genes involved in cellular communication including G-protein coupled, tyrosine kinase, and ion-channel regulated signaling pathways. The number and function of the downregulated genes suggest that DWV has a major impact on neuron signaling that could explain DWV related behavioral changes

Spatial modes for transmission of chikungunya virus during a large chikungunya outbreak in Italy: a modeling analysis

14openInternationalBothBackground The spatial spread of many mosquito-borne diseases occurs by focal spread at the scale of a few hundred meters and over longer distances due to human mobility. The relative contributions of different spatial scales for transmission of chikungunya virus require definition to improve outbreak vector control recommendations. Methods We analyzed data from a large chikungunya outbreak mediated by the mosquito Aedes albopictus in the Lazio region, Italy, consisting of 414 reported human cases between June and November 2017. Using dates of symptom onset, geographic coordinates of residence, and information from epidemiological questionnaires, we reconstructed transmission chains related to that outbreak. Results Focal spread (within 1 km) accounted for 54.9% of all cases, 15.8% were transmitted at a local scale (1–15 km) and the remaining 29.3% were exported from the main areas of chikungunya circulation in Lazio to longer distances such as Rome and other geographical areas. Seventy percent of focal infections (corresponding to 38% of the total 414 cases) were transmitted within a distance of 200 m (the buffer distance adopted by the national guidelines for insecticide spraying). Two main epidemic clusters were identified, with a radius expanding at a rate of 300–600 m per month. The majority of exported cases resulted in either sporadic or no further transmission in the region. Conclusions Evidence suggest that human mobility contributes to seeding a relevant number of secondary cases and new foci of transmission over several kilometers. Reactive vector control based on current guidelines might allow a significant number of secondary clusters in untreated areas, especially if the outbreak is not detected early. Existing policies and guidelines for control during outbreaks should recommend the prioritization of preventive measures in neighboring territories with known mobility flows to the main areas of transmission.openGuzzetta, Giorgio; Vairo, Francesco; Mammone, Alessia; Lanini, Simone; Poletti, Piero; Manica, Mattia; Rosa, Roberto; Caputo, Beniamino; Solimini, Angelo; Torre, Alessandra Della; Scognamiglio, Paola; Zumla, Alimuddin; Ippolito, Giuseppe; Merler, StefanoGuzzetta, G.; Vairo, F.; Mammone, A.; Lanini, S.; Poletti, P.; Manica, M.; Rosa, R.; Caputo, B.; Solimini, A.; Torre, A.D.; Scognamiglio, P.; Zumla, A.; Ippolito, G.; Merler, S

Spatial modes for transmission of chikungunya virus during a large chikungunya outbreak in Italy. A modeling analysis

Background The spatial spread of many mosquito-borne diseases occurs by focal spread at the scale of a few hundred meters and over longer distances due to human mobility. The relative contributions of different spatial scales for transmission of chikungunya virus require definition to improve outbreak vector control recommendations. Methods We analyzed data from a large chikungunya outbreak mediated by the mosquito Aedes albopictus in the Lazio region, Italy, consisting of 414 reported human cases between June and November 2017. Using dates of symptom onset, geographic coordinates of residence, and information from epidemiological questionnaires, we reconstructed transmission chains related to that outbreak. Results Focal spread (within 1 km) accounted for 54.9% of all cases, 15.8% were transmitted at a local scale (1–15 km) and the remaining 29.3% were exported from the main areas of chikungunya circulation in Lazio to longer distances such as Rome and other geographical areas. Seventy percent of focal infections (corresponding to 38% of the total 414 cases) were transmitted within a distance of 200 m (the buffer distance adopted by the national guidelines for insecticide spraying). Two main epidemic clusters were identified, with a radius expanding at a rate of 300–600 m per month. The majority of exported cases resulted in either sporadic or no further transmission in the region. Conclusions Evidence suggest that human mobility contributes to seeding a relevant number of secondary cases and new foci of transmission over several kilometers. Reactive vector control based on current guidelines might allow a significant number of secondary clusters in untreated areas, especially if the outbreak is not detected early. Existing policies and guidelines for control during outbreaks should recommend the prioritization of preventive measures in neighboring territories with known mobility flows to the main areas of transmission

Open Problems on Central Simple Algebras

We provide a survey of past research and a list of open problems regarding central simple algebras and the Brauer group over a field, intended both for experts and for beginners.Comment: v2 has some small revisions to the text. Some items are re-numbered, compared to v

Co-circulation of SARS-CoV-2 Alpha and Gamma variants in Italy, February and March 2021

Background. Several SARS-CoV-2 variants of concern (VOC) have emerged through 2020 and 2021. There is need for tools to estimate the relative transmissibility of emerging variants of SARS-CoV-2 with respect to circulating strains.AimWe aimed to assess the prevalence of co-circulating VOC in Italy and estimate their relative transmissibility.Methods. We conducted two genomic surveillance surveys on 18 February and 18 March 2021 across the whole Italian territory covering 3,243 clinical samples and developed a mathematical model that describes the dynamics of co-circulating strains.Results. The Alpha variant was already dominant on 18 February in a majority of regions/autonomous provinces (national prevalence: 54%) and almost completely replaced historical lineages by 18 March (dominant across Italy, national prevalence: 86%). We found a substantial proportion of the Gamma variant on 18 February, almost exclusively in central Italy (prevalence: 19%), which remained similar on 18 March. Nationally, the mean relative transmissibility of Alpha ranged at 1.55-1.57 times the level of historical lineages (95% CrI: 1.45-1.66). The relative transmissibility of Gamma varied according to the assumed degree of cross-protection from infection with other lineages and ranged from 1.12 (95% CrI: 1.03-1.23) with complete immune evasion to 1.39 (95% CrI: 1.26-1.56) for complete cross-protection.Conclusion. We assessed the relative advantage of competing viral strains, using a mathematical model assuming different degrees of cross-protection. We found substantial co-circulation of Alpha and Gamma in Italy. Gamma was not able to outcompete Alpha, probably because of its lower transmissibility

A tomographic analysis of reflectometry data I: Component factorization

Many signals in Nature, technology and experiment have a multi-component structure. By spectral decomposition and projection on the eigenvectors of a family of unitary operators, a robust method is developed to decompose a signals in its components. Different signal traits may be emphasized by different choices of the unitary family. The method is illustrated in simulated data and on data obtained from plasma reflectometry experiments in the tore Supra.Comment: 27 pages Latex, 17 figure

Transnational partisanship: idea and practice

That parties might successfully organize transnationally is an idea often met with scepticism. This article argues that while certain favourable conditions are indeed absent in the transnational domain, this implies not that partisanship is impossible but that it is likely to be marked by certain traits. Specifically, it will tend to be episodic, structured as a low-density network and delocalized in its ideational content. These tendencies affect the normative expectations one can attach to it. Transnational partisanship should be valued as a transitional phenomenon, e.g. as a pathway to transnational democracy, more than as a desirable thing in itself

First-principles calculations of the phase stability of TiO2

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