Large volcanic eruptions as a natural hazard: The impact of the 536/540 CE double event on the atmospheric circulation, surface climate, vegetation and society in Scandinavia

<p>Large volcanic eruptions that reach the stratosphere cool the surface climate and impact the atmospheric circulation, feeding back on the local climate. The mid-6<sup>th</sup> century is an outstanding period in climate history that featured an extreme cold period, including one of the coldest decades in the past 2000 years. It was triggered by the 536/540 CE volcanic double event, creating the strongest decadal volcanic forcing in the last two millennia. During this period societal changes are recorded around the world, like the Great Migration period and the outbreak of the Justinian Plague. However, not a lot is known about the causal relationships between global cooling and societal change. Less is known also, about the impact of the large-scale atmospheric circulation on the regional climate, vegetation and society in Scandinavia after this volcanic double event. Here we aim to improve this understanding by combining global climate and regional growing-degree-day (GGD) modeling with climate proxies and archaeological records from Southeastern Norway.</p><p>We use PMIP4 past2k runs and the MPI-ESM ensemble simulation of the 6<sup>th/7th </sup> century (520-680 CE), to analyze the atmospheric circulation, surface climate and vegetation changes as a response to the volcanic double event of 536/540 CE, over Scandinavia, specifically Southeastern Norway. Thereby we focus on the response of the major circulation patterns that influence the climate over Northern Europe: the positive and negative North Atlantic Oscillation, the Scandinavian blocking and the Atlantic ridge. The results of the GDD model, driven with the MPI-ESM model input, are compared to local pollen and climate records and archaeological data (e.g. grave density and settlement records) to shed more light on the local climate, vegetation and society impact. This comparison allows us to better understand how a natural hazard influenced local areas and climate records in Southeastern Norway. This study is part of the VIKINGS project, which focuses on the impact of volcanic eruptions on climate, environment and society in Norway/ Scandinavia.</p>

Optimal Falling Track Design for Twice detonating Fuze of Double event Fuel air Explosive with High Speed

To prevent the initiation failure caused by the uncontrolled fuze and improve the weapon reliability in the high-speed double-event fuel-air explosive (DEFAE) application, it is necessary to study the TDF motion trajectory and set up a twice-detonating fuze (TDF) design system. Hence, a novel approach of realising the fixed single-point center initiation by TDF within the fuel air cloud is proposed. Accordingly, a computational model for the TDF motion state with the nonlinear mechanics analysis is built due to the expensive and difficult full-scale experiment. Moreover, the TDF guidance design system is programmed using MATLAB with the equations of mechanical equilibrium. In addition, by this system, influences of various input parameters on the TDF motion trajectory are studied in detail singly. Conclusively, the result of a certain TDF example indicates that this paper provides an economical idea for the TDF design, and the developed graphical user interface of high-efficiency for the weapon designers to facilitate the high-speed DEFAE missile development.

Outbursts of the black hole X-ray transient KV UMa (XTE J1118+480) in the optical band

KV UMa (XTE J1118+480) is an X-ray binary that is known to undergo outbursts in 2000 and 2005. This paper presents the discovery of a large outburst starting in 1927 on the archival photographic plates and an analysis of the long-term optical activity of this system. We used the photographic data from DASCH (Digital Access to a Sky Century @ Harvard). We placed the 1927 outburst in the context of the observed outbursts of KV UMa. We show that it is a double event, with a precursor similar to the one of the outbursts in 2000. We find a big difference between the 1927 and 2000 outbursts as regards the length of the gap between the precursor and the main outburst. It is more than 250 d in 1927, whereas it is about 20 d in 2000, although the brightnesses of all peaks are mutually comparable. We also show that the individual optical outbursts of KV UMa differ from each other by the duration of the stage of a slow decline of brightness (sometimes roughly a plateau). This determines the length of the entire main outburst. Both the peak magnitude and the brightness of the outburst when the slow decline transitions to a steep final decaying branch plausibly reproduce in all three outbursts. In the interpretation, the short duration of the precursor is caused by the fact that only the thermal-viscous instability operated in the accretion disk while also the tidal instability of the disk contributed in the subsequent main outburst.

Variable Load Distribution for the Main Groups of Exercises in the Competitive Mesocycle of Highly Qualified Weightlifters

In weightlifting, throughout its existence, the search for optimal methods of organizing the training process is underway. In their works, researchers emphasize the importance of load distribution in annual periods, mesocycles, and microcycles. The aim of this study was to improve the training process of highly qualified weightlifters based on the application of diverse variations of load in intensity zones for the main groups of exercises in the microcycles of the competitive mesocycle. Working on the article, the authors analyzed scientific and methodological literature on the topic. The obtained data became the basis for the development of two options of a program for training weightlifters in a 4-week competitive mesocycle. The developed program was tested experimentally. In the course of the experiment, two equal experimental groups of eight people in each were formed from weightlifters with the qualification of master of sports of Russia. During the experiment, athletes of both groups performed the same amount of training load: 1608 NBL (number of barbell lifts). The load distribution for microcycles within the competition mesocycle was also the same for all athletes. The sequence of microcycles was as follows: recovery microcycle (340 NBL) → shock microcycle (603 NBL); → basic microcycle (483 NBL) → competitive microcycle (182 NBL). The authors assumed that with the same total load volumes and the identical sequence of types of microcycles in experimental groups, the variable distribution of load by intensity zones and main groups of exercises within individual microcycles of the competition mesocycle would allow achieving an increase in the result at competitions. The end of the experiment was the performance of athletes at all-Russian competitions. Athletes of Group 1 were able to improve the result in the total of the double event by 5.6 kg. Athletes of Group 2 showed a negative dynamics of results in the double event by 1.9 kg. The results of the study show that the increase in NBL in classical exercises by 8.5 % per month (competitive mesocycle) with a similar reduction in the load in special training exercises allows improving weightlifters’ competitive result without increasing the total amount of load under the following conditions: load in the snatch and jerk exercises in the intensity zones of 81–100% should increase by 40% per month; load reduction in pull exercises and barbell squats should be distributed relatively evenly across all applied intensity zones; load distribution by microcycles inside the competition mesocycle should follow the scheme: recovery → shock → basic → competitive; the greatest variations of load in classical and special preparatory exercises should be applied in the shock microcycle.

Proof of Concept: Pressure Sensor for Tracking of Infant-Mother Kangaroo Care Durations

Over the past two decades, there has been more of an emphasis by practitioners for mothers to perform skin-to-skin holding, known as Kangaroo Care (KC) due to the many benefits, such as decreased illness early in life, increased breastmilk production, and decreased chance of long term obesity for mother and child. Kangaroo Care is difficult in the NICU due to the health of the child and mother and numerous leads, IVs or breathing tubes attached to the child. With these problems, it is hard for mothers to follow best practices for performing KC, namely holding for a minimum of one hour and first hold within 24 hours of birth. Not following best practices lessens the benefits of KC for mother and child. Tracking of the duration of KC is often not measured by anyone including hospital staff so whether best practices are followed is difficult to know. Also, mothers may not have clothing that facilitates KC and there are few wearables specifically designed for mothers wanting to perform KC in the NICU. This project focuses on one part of designing a wearable that facilitates mothers performing KC while their child is in the NICU. To understand the effectiveness of said wearable, measuring how long the mothers are performing KC is needed. To accomplish this, a pressure sensor, incorporating Carbon Nanotube Fabric (CNT), was constructed to measure changes in pressure to track the number and duration of KC holds. As for the sensor, when a pressure is first applied or removed, the resistance changes rapidly but remains relatively constant with constant pressure. The average time difference between manually recording time and the sensor measurement was 4.06 seconds for a single event, such as applying a pressure to the sensor, and 6.66 seconds for a double event, such as the duration between when the pressure was applied to when it was removed. These results show that the sensor is accurate enough to measure the duration of KC for any period of time it is performed.