High-speed multi-dimensional relative navigation for uncooperative space objects

This work proposes a high-speed Light Detection and Ranging (LIDAR) based navigation architecture that is appropriate for uncooperative relative space navigation applications. In contrast to current solutions that exploit 3D LIDAR data, our architecture transforms the odometry problem from the 3D space into multiple 2.5D ones and completes the odometry problem by utilizing a recursive filtering scheme. Trials evaluate several current state-of-the-art 2D keypoint detection and local feature description methods as well as recursive filtering techniques on a number of simulated but credible scenarios that involve a satellite model developed by Thales Alenia Space (France). Most appealing performance is attained by the 2D keypoint detector Good Features to Track (GFFT) combined with the feature descriptor KAZE, that are further combined with either the H∞ or the Kalman recursive filter. Experimental results demonstrate that compared to current algorithms, the GFTT/KAZE combination is highly appealing affording one order of magnitude more accurate odometry and a very low processing burden, which depending on the competitor method, may exceed one order of magnitude faster computation

Controlling coaching and athlete thriving in elite adolescent netballers: The buffering effect of athletes' mental toughness

Objectives: The purposes of this study were to examine the association between controlling coach behaviours and athlete experiences of thriving and test the buffering effect of mental toughness on this relation. Design: A cross-sectional survey. Methods: In total, 232 female netballers aged 11 to 17 years (14.97 + 1.52) with between 1 and 15 years of experience in their sport (7.50 + 2.28) completed measures of controlling coach interpersonal style, mental toughness and thriving. Results: Latent moderated structural models indicated that (i) controlling coach behaviours were inversely related with experiences of vitality and learning; (ii) mental toughness was positively associated with psychological experiences of both dimensions of thriving; and (iii) mental toughness moderated the effect of coach's controlling interpersonal style on learning but not vitality experiences, such that the effect was weaker for individuals who reported higher levels of mental toughness. Conclusions: This study extends past work and theory to show that mental toughness may enable athletes to counteract the potentially deleterious effect of controlling coach interpersonal styles

COMMUNICATION COMPETENCE AS FUNDAMENTAL ASPECT FOR EFFECTIVE SCHOOL LEADERSHIP AND ADMINISTRATION ACHIEVING: A SYNOPTIC THEORETICAL APPROACH

Many theories and definitions regarding the concept of Leadership and Management appear in modern literature, as well as interpretations, references to specific characteristics and related topics. This fact shows that over time, a significant effort has been made to clarify the various dimensions of the concept of Leadership and its distinction from the concept of Management. The whole research activity gradually contributed to the development of an important framework in which various and remarkable theoretical models were developed, in parallel with the broader research that has been developed in the field of "human resource management", intending to study leadership styles and managerial behaviors to which they are connected. Many researchers agree that the position of traditional management is completely taken over today by Leadership, which is a complex but flexible, dynamic and at the same time creative resource management process. As has been observed, each new form of Leadership, developed during the 20th century, took into account the effectiveness of the previous one, both in theory and in practice. In this chapter, through three indicative sections, emphasis is placed on the clarification of the concepts of Leadership and Management, concise, conceptual approaches to Leadership Theories and Management Models are developed. Finally, reference is made to the modern, leading role of the School Principal. The characteristic of communication ability is underlined as a fundamental criterion for achieving effective school leadership and administration. Article visualizations

Holocene hydroclimatic changes in Northern Peloponnese (Greece) inferred from the multiproxy record of Lake Lousoi

This research presents the paleoenvironmental evolution of a drained lake at the Lousoi plateau (northern Peloponnese), for the last 10,000 years, through the study of a 7 m depth core. Analyses conducted on the core include grain size, TOC, TN, pH, EC, total carbonates (), magnetic susceptibility measurements, XRF analysis, and radiocarbon dating. Our paleoenvironmental reconstruction was based on geochemical proxiesrsquo; distribution in the core, combined with sediment physical and textural characteristics and later comparison between additional lacustrine archives from northern Peloponnese. From 10,900 to 7700 cal BP lacustrine, organic-rich deposits were recognized, reflecting increased lake water levels. Wet climatic conditions seem to have prevailed during this phase, interrupted by a dry pulse at 9400 cal BP. Transition to more shallow waters was marked at 8200 cal BP due to increased sediment deposition in the lake, with the environmental status shifting to a more oxygenated phase. Overall, wet conditions prevailed in this period and are in good agreement with regional records. In the Late Holocene period, the lake seems to have been highly affected by pedogenic processes, and thus, it was difficult to distinguish paleoclimatic/paleoenvironmental signals.1. Introduction 2. Study Area 2.1. Regional Setting 2.2. Geological Setting 3. Materials and Methods 3.1. Coring Fieldwork 3.2. Sedimentology 4. Results 4.1. Core Description and Stratigraphy 4.2. Radiocarbon Dating and Age–Depth Model 4.3. Distribution of Geochemical Proxies 5. Discussion 5.1. Early Holocene (11,800–8200 cal BP) 5.2. Middle Holocene (8200–4200 cal BP) 5.3. Late Holocene (4200 cal BP–Present) 6. Conclusion

On the Morgan-Shalen compactification of the SL(2,C) character varieties of surface groups

http://arxiv.org/PS_cache/math/pdf/9810/9810034v1.pdfA gauge theoretic description of the Morgan-Shalen compactification of the SL(2, C) character variety of the fundamental group of a hyperbolic surface is given in terms of a natural compactification of the moduli space of Higgs bundles via the Hitchin map

Evaluating 3D local descriptors for future LIDAR missiles with automatic target recognition capabilities

Future light detection and ranging seeker missiles incorporating 3D automatic target recognition (ATR) capabilities can improve the missile’s effectiveness in complex battlefield environments. Considering the progress of local 3D descriptors in the computer vision domain, this paper evaluates a number of these on highly credible simulated air-to-ground missile engagement scenarios. The latter take into account numerous parameters that have not been investigated yet by the literature including variable missile – target range, 6-degrees-of-freedom missile motion and atmospheric disturbances. Additionally, the evaluation process utilizes our suggested 3D ATR architecture that compared to current pipelines involves more post-processing layers aiming at further enhancing 3D ATR performance. Our trials reveal that computer vision algorithms are appealing for missile-oriented 3D ATR

Femur Stress Fracture - Marathon

HISTORY: During a race, a 35-year-old marathon runner complained of experiencing dull, achy pain in the right groin. After the race, he occasionally experienced radiating pain in the right thigh. The athlete was examined by a general practitioner (GP). During the clinical evaluation, the athlete had no signs of tenderness or swelling. The GP suggested rest and prescribed anti-inflammatory medication. PHYSICAL EXAMINATION: Ten days later, during training, the athlete felt the same discomfort after a challenging training session. He, then, decided to see an orthopedic physician. At the clinical examination, there was no localized pain. Focal pain was present during weight bearing activities only. Initial x-rays showed no significant abnormality or fracture. However, due to the complaints of the athlete, the doctor suggested additional x-rays and an MRI. DIFFERENTIAL DIAGNOSIS: Lumbar radiculopathy Rectus femoris strain Abductor strain Trochanteric bursitis TEST AND RESULTS: - X-ray showed a fracture of the middle shaft of the femur - MRI showed a medial periosteal reaction in the femoral shaft (high fluid signal) - Pain, especially during internal rotation - Pain on the affected side with a single-leg stance - Pain during activity, reproducible on passive range of motion FINAL / WORKING DIAGNOSIS: Stress fracture of the middle shaft of the right femur TREATMENT AND OUTCOMES: Tolerate weight bearing if no displacement occurs (four months max.) Treatment by a metabolic physician (Vitamin D deficiency or other) Continuing follow-up with repeated imaging: Verify resolution and minimize the progression to displacement Surgery if conservative management fails (see #1-3) Intramedullary rodding (surgical procedure

An integrated process of biodiesel production from indigenous microalgae in Northern Greece: first results

For environmental, economic and competence reasons, the fuel industry has pushed for alternative fuels in the past few years. One option that is considered are biofuels, which are renewable fuels and have the characteristic of lower or zero emissions of CO2 in the lifecycle, depending on their origin, their production and use. That is done, because the carbon they contain has been committed in the development of organic matter from the atmosphere, which returns after combustion so the balance of emissions throughout the life cycle of biofuel is "theoretically zero