805 research outputs found
Average Weighted Monthly SPEI values for NUTS2016 Dataset
No full textThis dataset provides average weighted values of the Standardised Precipitation-Evapotranspiration Index(SPEI) for various NUTS2016 levels. SPEI is a multi-scalar measure of drought severity frequently used in multi-disciplinary scholarly research to detect, observe and examine the onset and termination of drought episodes. The SPEI dataset used here originates from The SPEI Global Drought Monitor], which offers near real-time information about drought conditions worldwide, with a 1 degree spatial resolution and a monthly coverage from January 1950 until March 2021. It is based on the Thortnthwaite equation for estimating potential evapotranspiration or PET. Using this equation, SPEI is calculated as the the difference between the precipitation (P) and PET for every available month.While the Thortnthwaite equation is less superior to the FAO-56 Penman-Monteith estimation of potential evapotranspiration when it comes to long-term climatological analysis, there are several advantages of using the estimations from the SPEI Global Drought Monitor. The main advantage is its near real-time character, which is best suited for drought monitoring and early warning purposes. This dataset also relies on less robust methods of PET computation, allowing for a more efficient processing of the dataset. Finally, this dataset is updated during the first days of the following month based on the most reliable and updated sources of climatic data. Average temperature data are obtained from the NOAA NCEP CPC GHCN_CAMS gridded dataset while monthly precipitation sums data are obtained from the 'first guess' Global Precipitation Climatology Centre(GPCC). The SPEI data was downloaded from the https://soton.eead.csic.es/spei/10/nc/spei01.nc in the 1-month scale and imported as stacked raster file with 855 layers in total (each layer is a month-year ranging from January 1950 until March 2021). Missing values were assigned based on the value suggested by the authors of the original dataset. Next, the stacked raster was processed in R using exactextractr package for zonal statistics of multiband raster files, which summarizes pixel values over polygonal areas. The NUTS2016 polygons were obtained from Eurostat. Using one of the most common methods in zonal statistics, the mean value of every monthly SPEI cell was intersected by the polygon units for each NUTS2016 shapefile separately (NUTS0, NUTS1, NUTS2 and NUTS3) and then weighted by the fraction of the cell that is covered. The resulting values range from negative (higher drought levels) to positive (lower drought levels)
Replication Data for: Fragile proxies: Explaining rebel defection against their state sponsors
No full textForeign governments frequently intervene in armed conflicts by sponsoring rebels against their adversaries. A sponsorship is less costly than a direct military intervention, but rebels often defy orders, desert fighting, or turn guns against their sponsors. Under what conditions do rebels defect against their sponsors? Drawing on organizational theory, I argue that as rebel organizations become less centralized and formalized, the rebels are likely to defect against their sponsors. This occurs because non-centralized organizations have weak central leadership and allow for dispersed decision-making, both of which narrow the manipulative capacity of sponsors. Due to these disadvantages, non-centralized rebel movements are less accountable to their sponsors, cannot credibly commit to rapidly change their policies in response to changes in the sponsor’s demands, and suffer from frequent and destructive quarrels between the top and lower echelons. Using multilevel logistic models for panel data, I test my argument on a novel dataset. My quantitative analysis shows that rebel structure is a robust predictor of defection
The people behind the papers - Yonit Maroudas-Sacks and Marko Popovic
No full textDuring Hydra regeneration, supracellular actomyosin fibres are disoriented at two distinct foci of the regenerating tissue. These sites of nematic topological defects eventually form the new head and foot of the regenerated animal. In a new study, Yonit MaroudasSacks, Marko Popovic, Kinneret Keren and colleagues propose a positive-feedback loop that incorporates fibre organisation, tissue strain and morphogen gradients to promote head organiser formation. To find out more about the work, we caught up with first author Yonit Maroudas-Sacks and co-corresponding author Marko Popovic, Group Leader at the Max Planck Institute for the Physics of Complex Systems, Germany
Replication Data for: "Charm Offensive or Offensive Charm? An Analysis of Russian and Chinese Cultural Institutes Abroad" Milos Popovic , Erin K. Jenne , and Juraj Medzihorsky. Europe-Asia Studies. https://doi.org/10.1080/09668136.2020.1785397
No full textThis archive contains the replication files for "Charm Offensive or Offensive Charm? An Analysis of Russian and Chinese Cultural Institutes Abroad" Milos Popovic , Erin K. Jenne , and Juraj Medzihorsky. Europe-Asia Studies. https://doi.org/10.1080/09668136.2020.178539
Engineering Optical Forces in Waveguides and Cavities Based on Optical Response
No full textWe present a new treatment of optical forces, revealing that the forces in virtually all optomechanically variable systems can be computed exactly and simply from only the optical phase and amplitude response of the system. This treatment, termed the response theory of optical forces (or RTOF), provides conceptual clarity to the essential physics of optomechanical systems, which computationally intensive Maxwell stress-tensor analyses leave obscured, enabling the construction simple models with which optical forces and trapping potentials can be synthesized based on the optical response of optomechanical systems. A theory of optical forces, based on the optical response of systems, is advantageous since the phase and amplitude response of virtually any optomechanical system (involving waveguides, ring resonators or photonic crystals) can be derived, with relative ease, through well-established analytical theories. In contrast, conventional Maxwell stress tensor methods require the computation of complex 3-dimensional electromagnetic field distributions; making a theory for the synthesis of optical forces exceedingly difficult. Through numerous examples, we illustrate that the optical forces generated in complex waveguide and microcavity systems can be computed exactly through use of analytical scattering-matrix methods. When compared with Maxwell stress-tensor methods of force computation, perfect agreement is found.Sandia CorporationUnited States. National Nuclear Security Administration (contract DE-AC04-94AL85000)United States. Dept. of the Air Force. Office of the Director of Defense Research and Engineering (contract FA8721-05-C-0002
Optonanomechanical self-adaptive photonic devices based on light forces: A path to robust high-index-contrast nanophotonic circuits
No full textWe describe a proposed new class of optonanomechanical integrated photonic devices that can have self-adaptive behavior and self-adaptive optical frequency response, through the use of optical forces to manipulate their movable parts. We propose applications for this technology, and show how such devices can address the enormous dimensional and thermal sensitivity present in nanophotonic structures. Through synthesis of the optomechanical potential, we propose to design and control either the effective optical, or the mechanical, properties of the nanostructure, such as a giant effective optical nonlinear response, nonlinear dynamics and memory. We show device designs that can trap desired states at picometer resolution. We also describe the design of a novel, self-tuning microcavity design whose moving parts adjust in response to light forces alone to always place the resonance at the wavelength of the incident light over a wide wavelength range. This device concept provides an athermal resonator design (temperature-independent resonance frequency), without use of materials with negative thermooptic coefficients. It could also address a major challenge with conventional strong-confinement (high-index-contrast) integrated photonics - their extreme sensitivities - through a self-locking filter bank and optical cross-connect proposal, that in principle can use arbitrarily low power to trim resonant filter passbands to a wavelength channel grid.Director of Defense Research and Engineering (Air Force contract FA8721-05-C-0002
Post-War Pathways of Foreign Fighters from the Bosnian War (1992--1995)
No full textThis dataset is a part of project 798392 - MPP funded by Marie-Sklodowska Curie Actions Individual Fellowship, a scholarly grant awarded by the European Commission to Dr. Milos Popovic as the principal investigator (PI). In total, the dataset includes information on 95 individuals who fought in the Bosnian war (1991--1995) as foreign volunteers based on available online resources. It is by no means the universe of cases or a representative sample. The overarching aim of this research is to collect war memories for scientific and archival purposes.
\noindent The dataset is the first to date to include information on the Greek and Russian foreign fighters who fought on the side of the Army of the Serb Republic of Bosnia-Herzegovina. The dataset does not feature information on the former mujahideen fighters because there is little information on the individual fighters. The key resource used to gather information on the Greek volunteers is the massive investigative work of the XYZ contagion investigative work, which can be found at https://xyzcontagion.wordpress.com/2015/06/17/maria-lefteris-ethnos-tagmata-matosan-srebrenica/. Information on Russian foreign fighters comes mostly from two books published by former foreign fighters Mikhail Polikarpov and Oleg Valetskiy:
Валецкий, О. В. (1993). Волки белые. Сербский дневник русского добровольца (1993--1999), Грифон М;
Поликарпов, М. А. (2007). Сербский закат. Москва: Эксмо.
For data triangulation purposes, I also used a few online sources from Serbian forums as well as Soldier of Fortune issues (in Russian) for the period 1992-1995. In addition, Aziz Tafro's book Russian and Greek Henchmen in the war in Bosnia-Herzegovina provided useful information on the deceased Russian volunteers. Finally, I relied on numerous articles by former foreign fighters as well as interviews that they gave to various news portals
Dynamic cortical participation during bilateral, cyclical ankle movements: Effects of Parkinson's disease.
No full textParkinson's disease (PD) is known to increase asymmetry and variability of bilateral movements. However, the mechanisms of such abnormalities are not fully understood. Here, we aimed to investigate whether kinematic abnormalities are related to cortical participation during bilateral, cyclical ankle movements, which required i) maintenance of a specific frequency and ii) bilateral coordination of the lower limbs in an anti-phasic manner. We analyzed electroencephalographic and electromyographic signals from nine men with PD and nine aged-matched healthy men while they sat and cyclically dorsi- and plantarflexed their feet. This movement was performed at a similar cadence to normal walking under two conditions: i) self-paced and ii) externally paced by a metronome. Participants with PD exhibited reduced range of motion and more variable bilateral coordination. However, participants with and without PD did not differ in the magnitude of corticomuscular coherence between the midline cortical areas and tibialis anterior and medial gastrocnemius muscles. This finding suggests that either the kinematic abnormalities were related to processes outside linear corticomuscular communication or PD-related changes in neural correlates maintained corticomuscular communication but not motor performance
Post-War Pathways of Foreign Fighters from the Croatian War (1991--1995) Dataset
No full textThis dataset is a part of project 798392 - MPP funded by Marie-Sklodowska Curie Actions Individual Fellowship, a scholarly grant awarded by the European Commission to Dr Milos Popovic as the principal investigator(PI). In total, the dataset includes information on 25 individuals who fought in the Croatian war (1991–1995)as foreign volunteers based on in-person interviews conducted between August 2020 and August 2021 in Croatia and online. It is by no means the universe of cases or a representative sample. The overarching aim of this research is to collect war memories for scientific and archival purposes. All the interviews were set up and carried out by Tomislav Šulj a historian at the Croatian Homeland War Memorial Documentation Centre (https://centardomovinskograta.hr/). The interviewer adhered to a code of conduct approved by Leiden University and the European Commission. First, any participation in the interview was completely voluntary and the participants had the right to refuse participation or any question at any stage or withdraw at any time without any consequence whatsoever while preserving their anonymity. Second, potential interviewees were given a detailed study guidebook beforehand, including the description, aim and anonymity/confidentiality clauses. Third, the interviewees were asked to sign their consent to the use of interview data for scientific purposes, including the production of this dataset. Interviewees were also informed that their anonymity would be broken only under extraordinary circumstances when there is a serious risk of harm or danger to either the interviewer, interviewee or another individual (e.g. physical, emotional or sexual abuse, concerns for child protection, rape, self-harm, suicidal intent or criminal activity) or if a crime was committed. All the conversations were audio-recorded upon the interviewee’s explicit consent. Every signed consent form was scanned and placed together with Dr Popovic’s original audio recording of the interview. There are two copies of the interview notes and audio recordings. One copy is stored in an encrypted folder on Dr Popovic’s personal and office computer at the Institute of Security and Global Affairs in the Hague until after Dr Popovic’s project has ended on September 1, 2021. The second copy is stored and archived at the CroatianHomeland War Memorial Documentation Centre and, following the authorization of the interview transcript, used for research on the Croatian Homeland War. Under the provisions of the General Data Protection Regulation (EU) 2016/679 (GDPR), every interviewee is entitled to access the information they have provided at any time
Neuromuscular electrical stimulation and voluntary wrist extension movements elicit similar sensorimotor cortex activation: a continuous-wave fNIRS study
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