Disentangling the Entangled Linkages of Relative Magnetic Helicity

Magnetic helicity, $H$, measures magnetic linkages in a volume. The early theoretical development of helicity focused on magnetically closed systems in $\mathcal{V}$ bounded by $\mathcal{S}$. For magnetically closed systems, $\mathcal{V}\in\mathbb{R}^3=\mathcal{V}+\mathcal{V}^*$, no magnetic flux threads the boundary, $\hat{\boldsymbol{n}}\cdot\boldsymbol{B}|_\mathcal{S}=0$. Berger and Field (1984) and Finn and Antonsen (1985) extended the definition of helicity to relative helicity, $\mathcal{H}$, for magnetically open systems where magnetic flux may thread the boundary. Berger (1999,2003) expressed this relative helicity as two gauge invariant terms that describe the self helicity of magnetic field that closes inside $\mathcal{V}$ and the mutual helicity between the magnetic field that threads the boundary $\mathcal{S}$ and the magnetic field that closes inside $\mathcal{V}$. The total magnetic field that permeates $\mathcal{V}$ entangles magnetic fields that are produced by current sources $\boldsymbol{J}$ in $\mathcal{V}$ with magnetic fields that are produced by current sources $\boldsymbol{J}^*$ in $\mathcal{V}^*$. Building on this fact, we extend Berger's expressions for relative magnetic helicity to eight gauge invariant quantities that simultaneously characterize both of these self and mutual helicities and attribute their origins to currents $\boldsymbol{J}$ in $\mathcal{V}$ and/or $\boldsymbol{J}^*$ in $\mathcal{V}^*$, thereby disentangling the domain of origin for these entangled linkages. We arrange these eight terms into novel expressions for internal and external helicity (self) and internal-external helicity (mutual) based on their domain of origin. The implications of these linkages for interpreting magnetic energy is discussed and new boundary observables are proposed for tracking the evolution of the field that threads the boundary.Comment: 27 pages, 2 figure

The New Adult Education: Bringing Peer Educators Up to Speed

Stereotypes about peer educators (farmers teaching farmers, parent teaching parents) may get in Extension\u27s way. Problems occur particularly when it is believed that peer educators\u27 natural abilities are what make them great. This article provides an alternative view of peer educators, with a focus on ways to increase the educational skills of this important Extension partner. The article summarizes a new approach to adult education (constructivist and transformative) that was introduced to peer educators in Iowa (farmer cooperators and pesticide applicator educators) through workshops and support materials. The article also discusses challenges associated with adoption of new forms of adult education

Prairie Strips for Sediment and Nutrient Control and Biodiversity

Installation of prairie strips is a new conservation best management practice (BMP) that involves using a species-rich mix of native prairie grasses, forbs, and legumes. Prairie strips are planted along the contours of an agricultural field at the 10% level to manage potentially polluting runoff and are promising for control of nitrogen and phosphorus. Researchers used whole watersheds to replicate findings, providing a high degree of rigor in the study of this new BMP. Moreover, cooperating farmers and landowners have successfully used farm programs to subsidize prairie strip plantings. Besides sediment and nutrient control, an additional benefit is high plant biodiversity, which leads to more diverse and healthier wildlife and pollinator populations

Toezicht op media pluralisme in het digitale tijdperk. Toepassing van de Media Pluralisme Monitor in de Europese Unie, Albanië, Montenegro, de Republiek Noord-Macedonië, Servië en Turkije in 2021. Landenrapport : Nederland

This report presents the results of the implementation of the Media Pluralism Monitor for the year 2021 (MPM2022) in the Netherlands. The MPM is a holistic tool geared at assessing the risks to media pluralism in EU member states and selected candidate countries (32 European countries in total, including Albania, Montenegro, the Republic of North Macedonia, Serbia, and Turkey). The MPM takes into account legal, political and economic variables that are relevant to analysing the levels of plurality of media systems in a democratic society. The Media Pluralism Monitor has been implemented, on a regular basis, by the Centre for Media Pluralism and Media Freedom, since 2013/2014.The Centre for Media Pluralism and Media Freedom is co-financed by the European Unio

A global map of hemispheric influenza vaccine recommendations based on local patterns of viral circulation

Both the Northern and the Southern Hemisphere annual WHO influenza vaccine recommendations are designed to ensure vaccine delivery before the winter-time peak of viral circulation in each hemisphere. However, influenza seasonal patterns are highly diverse in tropical countries and may be out of phase with the WHO recommendations for their respective hemisphere. We modelled the peak timing of influenza activity for 125 countries using laboratory-based surveillance data from the WHO’s FLUNET database and compared it with the influenza hemispheric recommendations in place. Influenza vaccine recommendations for respectively 25% and 39% of the Northern and Southern Hemisphere countries were out of phase with peak influenza circulation in their corresponding hemisphere (62% and 53%, respectively, when the analysis was limited to the 52 countries in the tropical belt). These results indicate that routine influenza immunization efforts should be closely tailored to local patterns of viral circulation, rather than a country’s hemispheric position

Toezicht op media pluralisme in het digitale tijdperk : toepassing van de media pluralisme monitor in de Europese Unie, Albanië, Montenegro, de Republiek Noord-Macedonië, Servië en Turkije in 2022. Landenrapport : Nederland

This report presents the results of the implementation of the Media Pluralism Monitor for the year 2022 (MPM2023) in the Netherlands. The MPM is a holistic tool geared at assessing the risks to media pluralism in EU member states and selected candidate countries (32 European countries in total, including Albania, Montenegro, the Republic of North Macedonia, Serbia, and Turkey). The MPM takes into account legal, political and economic variables that are relevant to analysing the levels of plurality of media systems in a democratic society. The Media Pluralism Monitor has been implemented, on a regular basis, by the Centre for Media Pluralism and Media Freedom, since 2013/2014.In dit rapport worden de resultaten gepresenteerd van de implementatie van de Media Pluralisme Monitor in Nederland voor het jaar 2022 (MPM 2023). De MPM is een holistisch instrument dat gericht is op het inschatten van de risico's betreffende mediapluralisme in EU-lidstaten en geselecteerde kandidaat-lidstaten (32 Europese landen in totaal, waaronder Albanië, Montenegro, Republiek Noord-Macedonië, Servië en Turkije). De MPM houdt rekening met wettelijke, politieke en economische variabelen die relevant zijn voor een analyse van het niveau van pluraliteit van mediasystemen in een democratische samenleving. De Monitor Pluralisme Monitor wordt sinds 2013/2014 op regelmatige tijdstippen uitgevoerd door het Centrum voor Mediapluralisme en Mediavrijheid (CMPF).The Centre for Media Pluralism and Media Freedom is co-financed by the European Unio

Were equatorial regions less affected by the 2009 influenza pandemic? The Brazilian experience

Although it is in the Tropics where nearly half of the world population lives and infectious disease burden is highest, little is known about the impact of influenza pandemics in this area. We investigated the mortality impact of the 2009 influenza pandemic relative to mortality rates from various outcomes in pre-pandemic years throughout a wide range of latitudes encompassing the entire tropical, and part of the subtropical, zone of the Southern Hemisphere (+5°N to −35°S) by focusing on a country with relatively uniform health care, disease surveillance, immunization and mitigation policies: Brazil. To this end, we analyzed laboratory-confirmed deaths and vital statistics mortality beyond pre-pandemic levels for each Brazilian state. Pneumonia, influenza and respiratory mortality were significantly higher during the pandemic, affecting predominantly adults aged 25 to 65 years. Overall, there were 2,273 and 2,787 additional P&I- and respiratory deaths during the pandemic, corresponding to a 5.2% and 2.7% increase, respectively, over average pre-pandemic annual mortality. However, there was a marked spatial structure in mortality that was independent of socio-demographic indicators and inversely related with income: mortality was progressively lower towards equatorial regions, where low or no difference from pre-pandemic mortality levels was identified. Additionally, the onset of pandemic-associated mortality was progressively delayed in equatorial states. Unexpectedly, there was no additional mortality from circulatory causes. Comparing disease burden reliably across regions is critical in those areas marked by competing health priorities and limited resources. Our results suggest, however, that tropical regions of the Southern Hemisphere may have been disproportionally less affected by the pandemic, and that climate may have played a key role in this regard. These findings have a direct bearing on global estimates of pandemic burden and the assessment of the role of immunological, socioeconomic and environmental drivers of the transmissibility and severity of this pandemic

Photon Pair Generation in Silicon Micro-Ring Resonator with Reverse Bias Enhancement

Photon sources are fundamental components for any quantum photonic technology. The ability to generate high count-rate and low-noise correlated photon pairs via spontaneous parametric down-conversion using bulk crystals has been the cornerstone of modern quantum optics. However, future practical quantum technologies will require a scalable integration approach, and waveguide-based photon sources with high-count rate and low-noise characteristics will be an essential part of chip-based quantum technologies. Here, we demonstrate photon pair generation through spontaneous four-wave mixing in a silicon micro-ring resonator, reporting a maximum coincidence-to-accidental (CAR) ratio of 602 (+-) 37, and a maximum photon pair generation rate of 123 MHz (+-) 11 KHz. To overcome free-carrier related performance degradations we have investigated reverse biased p-i-n structures, demonstrating an improvement in the pair generation rate by a factor of up to 2, with negligible impact on CAR.Comment: 5 pages, 3 figure

Computer design of obligate heterodimer meganucleases allows efficient cutting of custom DNA sequences

Meganucleases cut long (>12 bp) unique sequences in genomes and can be used to induce targeted genome engineering by homologous recombination in the vicinity of their cleavage site. However, the use of natural meganucleases is limited by the repertoire of their target sequences, and considerable efforts have been made to engineer redesigned meganucleases cleaving chosen targets. Homodimeric meganucleases such as I-CreI have provided a scaffold, but can only be modified to recognize new quasi-palindromic DNA sequences, limiting their general applicability. Other groups have used dimer-interface redesign and peptide linkage to control heterodimerization between related meganucleases such as I-DmoI and I-CreI, but until now there has been no application of this aimed specifically at the scaffolds from existing combinatorial libraries of I-CreI. Here, we show that engineering meganucleases to form obligate heterodimers results in functional endonucleases that cut non-palindromic sequences. The protein design algorithm (FoldX v2.7) was used to design specific heterodimer interfaces between two meganuclease monomers, which were themselves engineered to recognize different DNA sequences. The new monomers favour functional heterodimer formation and prevent homodimer site recognition. This design massively increases the potential repertoire of DNA sequences that can be specifically targeted by designed I-CreI meganucleases and opens the way to safer targeted genome engineering