Direct observation of magnetization dynamics generated by nano-contact spin-torque vortex oscillators

Time-resolved scanning Kerr microscopy has been used to directly image the magnetization dynamics of nano-contact (NC) spin-torque vortex oscillators (STVOs) when phase-locked to an injected microwave (RF) current. The Kerr images reveal free layer magnetization dynamics that extend outside the NC footprint, where they cannot be detected electrically, but which are crucial to phase-lock STVOs that share common magnetic layers. For a single NC, dynamics were observed not only when the STVO frequency was fully locked to that of the RF current, but also for a partially locked state characterized by periodic changes in the core trajectory at the RF frequency. For a pair of NCs, images reveal the spatial character of dynamics that electrical measurements show to have enhanced amplitude and reduced linewidth. Insight gained from these images may improve understanding of the conditions required for mutual phase-locking of multiple STVOs, and hence enhanced microwave power emission.Comment: 10 pages, 3 figure

Media Reporting and Business Cycles: Empirical Evidence based on News Data

Recent literature suggests that news shocks could be an important driver of economic cycles. In this article, we use a direct measure of news sentiment derived from media reports. This allows us to examine whether innovations in the reporting tone correlate with changes in the assessment and expectations of the business situation as reported by firms in the German manufacturing sector. We fi nd that innovations in news reporting affect business expectations, even when conditioning on the current business situation and industrial production. The dynamics of the empirical model con rm theoretical predictions that news innovations affect real variables such as production via changes in expectations. Looking at individual sectors within manufacturing, we fi nd that macroeconomic news is at least as important for business expectations as sector-spefici c news. This is consistent with the existence of information complementarities across sectors

Emissões públicas de ações, volatilidade e insider information na Bovespa

O trabalho utiliza um estudo de evento para examinar os retornos de ações relacionados a emissões públicas por empresas brasileiras listadas na BOVESPA, realizadas entre 1992 e 2002, buscando determinar como o mercado reagiu antes, durante e depois da data do anúncio da emissão. Após utilizar a metodologia convencional de mensuração de retornos anormais por OLS, foram utilizados modelos ARCH e GARCH, que levam em consideração a heteroscedasticidade condicional da volatilidade dos retornos anormais, em mais de 70% da amostra, após a constatação da presença desses processos nos resíduos originais. Os resultados mostram que 1) há evidências de insider information antes da data do anúncio, (2) que ocorrem retornos anormais negativos na data do anúncio e (3) que, no período de um ano após as emissões, as ações das empresas que captaram recursos via underwriting tiveram retornos negativos após ajuste ao risco e ao mercado

Direct and seasonal legacy effects of the 2018 heat wave and drought on European ecosystem productivity

In summer 2018, central and northern Europe were stricken by extreme drought and heat (DH2018). The DH2018 differed from previous events in being preceded by extreme spring warming and brightening, but moderate rainfall deficits, yet registering the fastest transition between wet winter conditions and extreme summer drought. Using 11 vegetation models, we show that spring conditions promoted increased vegetation growth, which, in turn, contributed to fast soil moisture depletion, amplifying the summer drought. We find regional asymmetries in summer ecosystem carbon fluxes: increased (reduced) sink in the northern (southern) areas affected by drought. These asymmetries can be explained by distinct legacy effects of spring growth and of water-use efficiency dynamics mediated by vegetation composition, rather than by distinct ecosystem responses to summer heat/drought. The asymmetries in carbon and water exchanges during spring and summer 2018 suggest that future land-management strategies could influence patterns of summer heat waves and droughts under long-term warming

PERENCANAAN FDD-LTE MENGGUNAKAN FREKUENSI 1800MHZ PADA PERANCANGAN INDOOR BUILDING COVERAGE DI YOGYA KEPATIHAN BANDUNG

Material sebuah gedung merupakan salah satu penyebab dari terjadinya fading sehingga menghambat sinyal masuk ke dalam gedung yang mengakibatkan sinyal didalam gedung tersebut lemah. Pada gedung Yogya Kepatihan memiliki masalah terhadap kualitas jaringan didalamnya sehingga butuh dilakukannya perencanaan Indoor untuk mengatasi masalah tersebut. Berdasarkan hasil analisis dilakukannya walk test diperoleh nilai rata-rata dari RSRP sebesar -96 dBm dan SINR sebesar 8 dB, sedangkan drivetest sekitaran Gedung memperoleh hasil RSRP sebesar -72 dBm dan SINR sebesar 5 dB. Penerapan Indoor Building Coverage (IBC) ini menggunakan sistem Distributed Antenna System (DAS) dengan teknik FDD-LTE pita frekuensi 1800 MHz, untuk simulasinya menggunakan Radiowave Propagation Software (RPS) dengan model propagasi Cost-231 Multi-Wall Indoor. Operator Telkomsel menjadi kasus dalam penerapan ini. Walktest di dalam gedung menggunakan Nemo handy, sedangkan drivetest menggunakan GnetTrack Pro. Setelah mendapatkan data lalu dilanjutkan perhitungan capacity planning dan coverage planning sehingga mendapatkan perhitungan untuk jumlah antena yang akan di simulasikan ke dalam software RPS untuk mendapatkan hasil parameter yang sesuai dengan standar Key Performance Indicator (KPI) Operator Telkomsel yaitu RSRP > -85 dBm dan SINR > 10 dB. Dari hasil simulasi ini, diperoleh peningkatan nilai rata-rata RSRP > -76 dBm sebanyak 81,95% dan rata-rata nilai SINR > 26 sebanyak 71,56%. Kata Kunci: LTE, FDD, IBC, DAS, RPS

Optically detected spin-orbit torque ferromagnetic resonance in an in-plane magnetized ellipse (article)

This is the author accepted manuscript. The final version is available from AIP Publishing via the DOI in this recordThe dataset associated with this article is available in ORE at: https://doi.org/10.24378/exe.3343Time-resolved scanning Kerr microscopy has been used to perform optically-detected, phaseresolved spin-orbit torque ferromagnetic resonance (SOT-FMR) measurements on a microscale CoFeB ellipse at the centre of a Pt Hall cross subject to RF and DC current. Time-resolved polar Kerr images revealed localized dynamics with large amplitude at the center, and weaker amplitude at the edges. Therefore, field swept SOT-FMR spectra were acquired from the so-called center mode to probe the SOTs active at the center of the ellipse, thus minimising non-uniform edge contributions. When the magnetic field was applied at 30° from the hard axis of the ellipse and a DC current applied, a marked asymmetry was observed in the amplitude and linewidth of the FMR peaks as the applied field was reversed. Both absorptive and dispersive parts of the spectra were in good agreement with a macrospin calculation. The damping parameter (α) and the Slonczewski torque parameter (ST) were determined to be 0.025 and (6.75±0.75)×10-7 Oe A-1 cm2 respectively. The hard axis SOT-FMR linewidth was found to be almost independent of the DC current value, suggesting that the SOT has minimal influence in the hard axis configuration and also that thermal effects were insignificant. This study paves the way to spatially-resolved measurements of SOT probed using localized modes of microscale devices that go beyond the spatially averaged capability of electrical measurement techniques.Engineering and Physical Sciences Research Council (EPSRC

Cis and Trans Effects of Human Genomic Variants on Gene Expression

This work was funded by the Louis-Jeantet Foundation (http://www.jeantet.ch/), the European Research Council (Grant ID: 260927 http://erc.europa.eu/), the Swiss National Foundation (Grant ID: 130342 http://www.snf.ch), NCCR Frontiers In Genetics (http://www.frontiers-in-genetics.org), the UK Medical Research Council (http://www.mrc.ac.uk) and the Wellcome Trust (Grant ID: 092731).

Accommodating to English-medium instruction in teacher education in Finland

This study analyses teacher educators’ and student teachers’ perceptions of teaching and learning situations in an international English as a lingua franca (ELF) context in an English-medium instruction (EMI) teacher education programme in Finland. The analysis of semi-structured interviews revealed that the participants perceived a partial reversal of traditional teacher and student roles; students assisted voluntarily and teaching became reciprocal. Some teachers reflected on having used typical strategies in ELF context such as code-switching to further communication and engage students. However, teachers’ lack of fluency was sometimes considered causing frustration among students and affected negatively their feeling of being professional teacher educators. Nevertheless, by increasing more learner-led activities, ELF can positively affect teacher education pedagogy.Peer reviewe