Spontaneous dynamic systems have attracted significant attention for their rich underlying physics such as phase-locking and synchronization. In this work, we report a new mechanism of generating magnetic spontaneous oscillation via parametric pumping. By applying a pump tone to excite propagating spin waves in a yttrium iron garnet delay line, four-wave mixing converts the pump mode into two phase-autonomous propagating magnon modes, i.e. a spontaneous mode with nearly twice the wavenumber of the pump mode and an idler mode with nearly zero wavenumber. This allows us to reliably generate ultrasharp spin wave dynamics with broad frequency tunability from the pump and magnetic field. We show that the spontaneous mode can be phase-locked to a probe tone, similar to an auto-oscillator. Furthermore, the spontaneous dynamics can be used to implement a high-gain magnonic parametric amplifier with a gain up to 40 dB. Our results open a new avenue for studying nonlinear magnonics and synchronization physics in propagating magnon geometry and for developing new magnonic devices.
We present a practical implementation of a phase-coherent mapping technique for pulsar timing arrays that resolves the full complex polarisation state of the gravitational-wave sky as a function of direction and frequency. Unlike standard cross-correlation methods, this approach preserves the amplitude, phase, and polarisation of the signal in every sky pixel. The resulting maps constitute a compact, minimally processed summary of the data from which all subsequent analyses – characterisation of a stochastic background, searches for anisotropy, and identification of individual sources – can be derived within a single unified framework. Our implementation is fully compatible with established pulsar timing data analysis methods. We validate the framework through a series of realistic simulations with varying array configurations, noise properties, and signal types. We demonstrate robust recovery of source amplitudes and sky locations across different scenarios, and discuss the impact of polarisation leakage, noise, and direction-dependent array sensitivity on the recovery of astrophysical signals.
The Arctic is warming faster than any other region globally, driving changes in terrestrial ecosystems and the cryosphere. However, lake ice phenology trends in the Novaya Zemlya Archipelago (NZA), Russian High Arctic, remain poorly understood. The region's harsh climate and limited accessibility hinder the collection of essential field-based lake ice data required to measure annual changes and validate remote-sensing observations. To address this gap, we analyzed daily Moderate Resolution Imaging Spectroradiometer imagery to examine seasonal lake ice breakup from 2000 to 2024 in 20 of the largest lakes in the NZA. Using the Google Earth Engine platform, Normalized Difference Snow Index band thresholds were applied to lake pixels to detect seasonal lake ice breakup. The average breakup date from 2000 to 2024 was July 8, with variations depending on latitude ranging from June 21 to July 21. The study revealed a significant trend toward earlier ice-free conditions across all lakes, averaging 14 days earlier over the 25-year period (5.6 days/decade), corresponding to significant increases in spring air and summer sea surface temperatures. These findings highlight the accelerating impact of warming on high-latitude systems and underscore the importance of sustained regional monitoring to anticipate future cryospheric shifts in the Arctic.
Background and aims – Plants display a variety of resistance and tolerance responses to herbivory. Compensation, or changes in growth, allocation, and/or physiology, after damage is one way that plants tolerate herbivory, but geographic patterns in intraspecific plant compensatory responses are understudied. We aimed to study geographic variation in tolerance to herbivory to help explain geographic patterns in the distribution of resistance traits and the relationship between tolerance and resistance traits in common milkweed, Asclepias syriaca. Material and methods – We grew milkweed from 14 different populations in the greenhouse, mechanically applied 25% leaf damage to an experimental group, and compared the control and experimental groups to measure compensatory responses in final biomass, root:shoot ratios, stem investment, and relative growth rate. We compared compensatory responses across populations grouped by latitude and by temperature. Key results – Compared to controls, milkweed plants that were damaged lost mass and expressed reduced root:shoot ratios. However, the effect of damage on total mass, stem investment, and relative growth rate varied among genetic families. In regional contrasts, plants from colder climates grew larger and invested less in stems and roots than plants from warmer climates under control conditions, but they were less able to compensate for damage in terms of biomass. Plants from cold regions also showed a tendency to reduce growth rate and stem investment after damage; whereas, plants from warmer climates tended to increase their growth rate and stem investment in response to damage. Conclusion – While plants from high latitudes and colder climates were less able to compensate for damage than those from lower latitudes, we are not confident that these differences are caused by geographic differences in growth rate, or that they explain differences in resistance to herbivory. Instead, we suspect that differences in the phenology of development in plants from regions with different climates affect the impact of damage and the potential for compensatory growth. Milkweed plants from colder regions with short growing seasons grew larger during our measurement period, while those from regions with longer growing seasons invested more in stems and roots, traits which may have facilitated greater long-term growth, as well as the greater compensatory ability observed in our study. Future studies should explicitly manipulate the timing of damage applied to plants from different regions to test the relationship between phenology and compensation.
ABSTRACT The purpose of this review is to provide practitioners with knowledge for developing an athlete assessment system and to help inform coaches and researchers about the research process, should they choose to publish assessment data. Information related to evidence-based practice methods will help readers formulate a critical approach to research for enhancing performance outcomes. Precursors to data collection involve pretesting certifications, laboratory set up, data collection, and testing protocols. This includes medical clearance and considerations for how the testing session will run. Other considerations include the following: where the data will get collected (laboratory vs. field), assessment selection, and ensuring the athletes are adequately prepared and familiarized with the protocol. Approaching data collection involves addressing factors related to assessments, athletes, and additional considerations. Factors related to assessments cover the quantity and quality of the staff collecting the data, cost and selection of equipment, time, the environment, and data management. Factors related to athletes include the fatigue accumulated from previous tests or training, the athlete's knowledge of the assessment, and their ability to give maximal effort and remain motivated throughout data collection. Additional considerations cover aspects of assessment, validity, and reliability.
