Experimental Control and Characterization of Autophagy in Drosophila

Insects such as the fruit fly Drosophila melanogaster, which fundamentally reorganize their body plan during metamorphosis, make extensive use of autophagy for their normal development and physiology. In the fruit fly, the hepatic/adipose organ known as the fat body accumulates nutrient stores during the larval feeding stage. Upon entering metamorphosis, as well as in response to starvation, these nutrients are mobilized through a massive induction of autophagy, providing support to other tissues and organs during periods of nutrient deprivation. High levels of autophagy are also observed in larval tissues destined for elimination, such as the salivary glands and larval gut. Drosophila is emerging as an important system for studying the functions and regulation of autophagy in an in vivo setting. In this chapter we describe reagents and methods for monitoring autophagy in Drosophila, focusing on the larval fat body. We also describe methods for experimentally activating and inhibiting autophagy in this system and discuss the potential for genetic analysis in Drosophila to identify novel genes involved in autophagy

Ubiquitous robust communications for emergency response using multi-operator heterogeneous networks

A number of disasters in various places of the planet have caused an extensive loss of lives, severe damages to properties and the environment, as well as a tremendous shock to the survivors. For relief and mitigation operations, emergency responders are immediately dispatched to the disaster areas. Ubiquitous and robust communications during the emergency response operations are of paramount importance. Nevertheless, various reports have highlighted that after many devastating events, the current technologies used, failed to support the mission critical communications, resulting in further loss of lives. Inefficiencies of the current communications used for emergency response include lack of technology inter-operability between different jurisdictions, and high vulnerability due to their centralized infrastructure. In this article, we propose a flexible network architecture that provides a common networking platform for heterogeneous multi-operator networks, for interoperation in case of emergencies. A wireless mesh network is the main part of the proposed architecture and this provides a back-up network in case of emergencies. We first describe the shortcomings and limitations of the current technologies, and then we address issues related to the applications and functionalities a future emergency response network should support. Furthermore, we describe the necessary requirements for a flexible, secure, robust, and QoS-aware emergency response multi-operator architecture, and then we suggest several schemes that can be adopted by our proposed architecture to meet those requirements. In addition, we suggest several methods for the re-tasking of communication means owned by independent individuals to provide support during emergencies. In order to investigate the feasibility of multimedia transmission over a wireless mesh network, we measured the performance of a video streaming application in a real wireless metropolitan multi-radio mesh network, showing that the mesh network can meet the requirements for high quality video transmissions

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

The Use of Thought Experiments in Teaching Physics to Upper Secondary-Level Students: Two examples from the theory of relativity

The present study focuses on the way thought experiments (TEs) can be used as didactical tools in teaching physics to upper secondary-level students. A qualitative study was designed to investigate to what extent the TEs called 'Einstein's elevator' and 'Einstein's train' can function as tools in teaching basic concepts of the theory of relativity to upper secondary-level students. The above TEs were used in the form they are presented by Einstein himself and by Landau and Rumer in books that popularize theories of physics. The research sample consisted of 40 Greek students, divided into 11 groups of three to four students each. The findings of this study reveal that the use of TEs in teaching the theory of relativity can help students realize situations which refer to a world beyond their everyday experience and develop syllogisms according to the theory. In this way, students can grasp physics laws and principles which demand a high degree of abstract thinking, such as the principle of equivalence and the consequences of the constancy of the speed of light to concepts of time and space. © 2013 Copyright Taylor and Francis Group, LLC

From Earth to Heaven: Using 'Newton's Cannon' Thought Experiment for Teaching Satellite Physics

Thought Experiments are powerful tools in both scientific thinking and in the teaching of science. In this study, the historical Thought Experiment (TE) 'Newton's Cannon' was used as a tool to teach concepts relating to the motion of satellites to students at upper secondary level. The research instruments were: (a) a teaching-interview designed and implemented according to the Teaching Experiment methodology and (b) an open-ended questionnaire administered to students 2 weeks after the teaching-interview. The sample consisted of forty students divided into eleven groups. The teaching and learning processes which occurred during the teaching-interview were recorded and analyzed. The findings of the present study show that the use of the TE helped students to mentally construct a physical system which has nothing to do with their everyday experience (i.e. they had to imagine themselves as observers in a context in which the whole Earth was visible) and to draw conclusions about phenomena within this system. Specifically, students managed (1) to conclude that if an object is appropriately launched, it may be placed in an orbit around the Earth and to support this conclusion by giving necessary arguments, and (2) to realize that the same laws of physics describe, on the one hand, the motion of the Moon around the Earth (and the motion of other celestial bodies as well) and, on the other hand, the motion of 'terrestrial' objects (i.e. objects on the Earth, such as a tennis ball). The main difficulties students met were caused by their idea that there is no gravity in the vacuum (i.e. the area outside of the Earth's atmosphere) and also by their everyday experience, according to which it is impossible for a projectile to move continuously parallel to the ground. © 2013 Springer Science+Business Media Dordrecht

The 'Heisenberg's Microscope' as an Example of Using Thought Experiments in Teaching Physics Theories to Students of the Upper Secondary School

In this work an attempt is made to explore the possible value of using Thought Experiments (TEs) in teaching physics to upper secondary education students. Specifically, a qualitative research project is designed to investigate the extent to which the Thought Experiment (TE) called 'Heisenberg's Microscope', as it has been transformed by Gamow for the public in his book Mr. Tompkins in Paperback, can function as a tool in the teaching of the 'uncertainty principle'. The sample in the research consisted of 40 Greek students, in 11 groups of 3-4 students each. The findings of this study reveal that the use of this TE has positive results in teaching the uncertainty principle. Students, based on the TE, were able (i) to derive a formula of the uncertainty principle, (ii) to explain that the uncertainty principle is a general principle in nature and it is not a result of incompleteness of the experimental devices and (iii) to argue that it is impossible to determine the trajectory of a particle as a mathematical line. © 2010 Springer Science+Business Media B.V

Scientific explanations in Greek upper secondary physics textbooks

In this study, an analysis of the structure of scientific explanations included in physics textbooks of upper secondary schools in Greece was completed. In scientific explanations for specific phenomena found in the sample textbooks, the explanandum is a logical consequence of the explanans, which in all cases include at least one scientific law (and/or principle, model or rule) previously presented, as well as statements concerning a specific case or specific conditions. The same structure is also followed in most of the cases in which the textbook authors explain regularities (i.e. laws, rules) as consequences of one or more general law or principle of physics. Finally, a number of the physics laws and principles presented in textbooks are not deduced as consequences from other, more general laws, but they are formulated axiomatically or inductively derived and the authors argue for their validity. Since, as it was found, the scientific explanations presented in the textbooks used in the study have similar structures to the explanations in internationally known textbooks, the findings of the present work may be of interest not only to science educators in Greece, but also to the community of science educators in other countries. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Relationships between gaze behavior and motor behavior in complex aerial skills

Velentzas K, Heinen T, Sato Y. Relationships between gaze behavior and motor behavior in complex aerial skills. In: Heinen T, Čuk I, Goebel R, Velentzas K, eds. Gymnastics Performance and Motor Learning – Principles and Applications. Sport and Athletics Preparation, Performance, and Psychology. NY: Nova; 2016

Thought experiments in the theory of relativity and in quantum mechanics: Their presence in textbooks and in popular science books

This work investigates the presence of Thought Experiments (TEs) which refer to the theory of relativity and to quantum mechanics in physics textbooks and in books popularizing physics theories. A further point of investigation is whether TEs - as presented in popular physics books - can be used as an introduction to familiarize secondary school students with physics theories of the 20th century. The study of textbooks and popular physics books showed that authors of both types of books consider TEs as an important tool when presenting the theory of relativity and quantum mechanics. Furthermore, a qualitative research conducted in secondary education revealed that the historical TEs which were transformed into forms accessible to the public could trigger students' interest and act as educational material to familiarize them with concepts and principles of the 20th century physics. © Springer Science+Business Media B.V. 2007

The measurement of mental representations within the context of motor actions

Velentzas K, Henning L, Jeraj D. The measurement of mental representations within the context of motor actions. In: Heinen T, Čuk I, Goebel R, Velentzas K, eds. Gymnastics Performance and Motor Learning – Principles and Applications. New York: Nova; 2016: 89-118