scholarly journals A Molecular Odorant Transduction Model and the Complexity of Combinatorial Encoding in the Drosophila Antenna

2017 ◽  
Author(s):  
Aurel A. Lazar ◽  
Chung-Heng Yeh
Keyword(s):  
Theoretical Foundation ◽  
Odorant Receptor ◽  
Fruit Fly ◽  
Dissociation Rate ◽  
Odorant Receptors ◽  
Molecular Models ◽  
The Past ◽  
Binding Rate ◽  
Combinatorial Encoding ◽  
Key Aspects

AbstractIn the past two decades, a substantial amount of work characterized the odorant receptors, neuroanatomy and odorant response properties of the early olfactory system of Drosophila melanogaster. Yet many odorant receptors remain only partially characterized and, the odorant transduction process and the axon hillock spiking mechanism of the olfactory sensory neurons (OSNs) have yet to be fully determined.Identity and concentration, two key aspects of olfactory coding, originate in the odorant transduction process. Detailed molecular models of the odorant transduction process are, however, scarce for fruit flies. To address these challenges we advance a comprehensive model of fruit fly OSNs as a cascade consisting of an odorant transduction process (OTP) and a biophysical spike generator (BSG). We model identity and concentration in OTP using an odorant-receptor binding rate tensor, modulated by the odorant concentration profile, and an odorant-receptor dissociation rate tensor, and quantitatively describe the ligand binding/dissociation process. We model the BSG as a Connor-Stevens point neuron.The resulting combinatorial encoding model of the Drosophila antenna provides a theoretical foundation for understanding the neural code of both odorant identity and odorant concentration and advances the state-of-the-art in a number of ways. First, it quantifies on the molecular level the combinatorial complexity of the transformation taking place in the antennae. The concentration-dependent combinatorial code determines the complexity of the input space driving olfactory processing in the downstream neuropils, such as odorant recognition and olfactory associative learning. Second, the model is biologically validated using multiple electrophysiology recordings. Third, the model demonstrates that the currently available data for odorant-receptor responses only enable the estimation of the affinity of the odorant-receptor pairs. The odorant-dissociation rate is only available for a few odorant-receptor pairs. Finally, our model calls for new experiments for massively identifying the odorant-receptor dissociation rates of relevance to flies.

Remaking Retirement

2020 ◽  
Keyword(s):  
Interest Rates ◽  
Older Workers ◽  
Older Persons ◽  
The United States ◽  
Older Population ◽  
The Past ◽  
Cost Of Education ◽  
The World ◽  
Low Interest Rates ◽  
Key Aspects

Around the world, people nearing and entering retirement are holding ever-greater levels of debt than in the past. This is not a benign situation, as many pre-retirees and retirees are stressed about their indebtedness. Moreover, this growth in debt among the older population may render retirees vulnerable to financial shocks, medical care bills, and changes in interest rates. Contributors to this volume explore key aspects of the rise in debt across older cohorts, drill down into the types of debt and reasons for debt incurred by the older population, and review policies to remedy some of the financial problems facing older persons, in the United States and elsewhere. The authors explore which groups are most affected by debt, and they also identify the factors causing this important increase in leverage at older ages. It is clear that the economic and market environments are influential when it comes to saving and debt. Access to easy borrowing, low interest rates, and the rising cost of education have had important impacts on how much people borrow, and how much debt they carry at older ages. In this environment, the capacity to manage debt is ever more important as older workers lack the opportunity to recover for mistakes.

The functions and positions of political parties in consociational democracies: theoretical and empirical contexts

2020 ◽  
pp. 28-33
Author(s):  
O. Morhuniuk
Keyword(s):  
Political Parties ◽  
The Netherlands ◽  
Party System ◽  
Party Competition ◽  
European Countries ◽  
The Past ◽  
Democratic Regimes ◽  
Wide Range ◽  
Key Aspects ◽  
Further Development

An article is devoted to the analysis of the functions and formats of political parties in consociational democracies. In particular, it is defined that parties that represent the interests of certain subcultures in society and that reach a consensus among themselves at the level of political agreements are called segmental. At the same time, parties that encapsulate different subgroups of the society that cooperate inside the party within main features of the consociational theory (grand coalition, mutual veto, proportionality in representations, and independence of segments or society subcultures) are called consociational. The theory of consociationalism has received a wide range of theoretical additions and criticism from political scientists over the past fifty years. And while political parties should have been, by definition, one of the key aspects of research within such democratic regimes (parties are part of large coalitions and agents of representation of certain subcultures), there is very scarce number of literature that focuses on this aspect. Therefore, the presented article provides a description of the functions of political parties that could be observed as inside their subcultures as well as in interaction with other segmental parties. Based on the experience of two European countries in the period of “classical” consociationalism (Belgium and the Netherlands), we explain the functions of the parties we have defined in such societies with examples of relevant consociational practices in them. Simultaneously with the analysis of segmental parties, the article also offers the characteristics of consociational parties. The emergence of such parties has its own institutional and historical features. The way of further development of the party system and the level of preservation of consociational practices makes it possible to understand the nature of changes in the societies. Similarly, the analysis of the forms of party competition and interaction between segmental parties makes it possible to outline the forms of those consociational changes that are taking place in the research countries.

Using Multilayer Perceptron Computation to Discover Ideal Insect Olfactory Receptor Combinations in the Mosquito and Fruit Fly for an Efficient Electronic Nose

2015 ◽  
Vol 27 (1) ◽  
pp. 171-201 ◽  
Author(s):  
Luqman R. Bachtiar ◽  
Charles P. Unsworth ◽  
Richard D. Newcomb
Keyword(s):  
Electronic Nose ◽  
Model Organism ◽  
Olfactory Receptors ◽  
Fruit Fly ◽  
Classification Performance ◽  
Performance Comparison ◽  
Odorant Receptors ◽  
Multilayer Perceptrons ◽  
Full Complement ◽  
Mosquito Anopheles Gambiae

The model organism, Drosophila melanogaster, and the mosquito Anopheles gambiae use 60 and 79 odorant receptors, respectively, to sense their olfactory world. However, a commercial “electronic nose” in the form of an insect olfactory biosensor demands very low numbers of receptors at its front end of detection due to the difficulties of receptor/sensor integration and functionalization. In this letter, we demonstrate how computation via artificial neural networks (ANNs), in the form of multilayer perceptrons (MLPs), can be successfully incorporated as the signal processing back end of the biosensor to drastically reduce the number of receptors to three while still retaining 100% performance of odorant detection to that of a full complement of receptors. In addition, we provide a detailed performance comparison between D. melanogaster and A. gambiae odorant receptors and demonstrate that A. gambiae receptors provide superior olfaction detection performance over D. melanogaster for very low receptor numbers. The results from this study present the possibility of using the computation of MLPs to discover ideal biological olfactory receptors for an olfactory biosensor device to provide maximum classification performance of unknown odorants.

scholarly journals New Potential Solutions for Mentors in the Development of Physical Education Teachers

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
István Győri ◽  
József Márton Pucsok ◽  
Melinda Biró
Keyword(s):  
Higher Education ◽  
Professional Development ◽  
Teacher Education ◽  
Public Education ◽  
Physical Education ◽  
Physical Education Teachers ◽  
The Past ◽  
Key Aspects ◽  
Special Factors

  The Hungarian Educational System, the Higher Education also Teacher Education have been constantly changing over the past decades. According to the results of international and domestic examinations, there is an increasing need for new standards and approaches,  in the entire Public Education, especially Teacher Education sector. The purpose of our study was to examine the key aspects of the mentoring process in physical education. We were trying to identify those special factors and identify new trends in the area of physical education. What is the role of these factors in the process of professional development of a teacher.  

scholarly journals Virantanaz – an epic in Vepsian? About the first attempt at an epic

2015 ◽  
Vol 6 (1) ◽  
pp. 157-174
Author(s):  
Nina Zaitseva
Keyword(s):  
Language And Culture ◽  
The Past ◽  
Literary Forms ◽  
The People ◽  
Key Aspects

The paper is a brief account of the events of the past 20 years, which have been essential for the fate of the Veps, and brought the author, who found herself in the very heart of the processes of Vepsian language and culture revival, to the idea of creating the epic. Can one create an epic in the language of a people (Vepsians in our case) whose memory has preserved no epic-style pieces of literature, no large oral literary forms, whose folklore heritage is not so rich, the nation itself is a minority, and its language is already red-listed? Or should one? Writing the work was a chance to retrieve from the people’s memory many facts, real or imaginary events, rituals, customs and legends, melodious idioms and sayings, which might help revitalise the people, its language and culture. The paper demonstrates the folklore and mythological background of the epic, represents and substantiates the key aspects of the style poetics, its folk heritage roots.

scholarly journals HOW SOCIAL MEDIA AFFORDS POPULIST POLITICS: REMARKS ON LIMINALITY BASED ON THE BRAZILIAN CASE

2020 ◽  
Vol 59 (1) ◽  
pp. 404-427
Author(s):  
Leticia Cesarino
Keyword(s):  
Social Media ◽  
Public Sphere ◽  
Discourse Markers ◽  
Online Ethnography ◽  
The Public ◽  
The Past ◽  
Making Sense ◽  
The Public Sphere ◽  
Key Aspects ◽  
And Linguistics

ABSTRACT In the past decade or so, populism and social media have been outstanding issues both in academia and the public sphere. At this point, evidence from multiple countries suggest that perceived parallels between the dynamics of social media and the mechanics of populist discourse may be more than just incidental, relating to a shared structural field. This article suggests one possible path towards making sense of how the dynamics of social media and the mechanics of populist mobilization have co-produced each other in the last decade or so. Navigating the interface between anthropology and linguistics, it takes key aspects of Victor Turner’s notion of liminality to suggest some of the ways in which social media’s anti-structural affordances may help lay a foundation for the contemporary flourishing of populist discourse: markers of social structure are suspended; communitas is formed; the culture core is addressed; mimesis and anti-structural inversions are performed; subjects become influenceable. I elaborate on this claim based on Brazilian materials, drawn from online ethnography on pro-Bolsonaro WhatsApp groups and other platforms such as Twitter and Facebook since 2018.

Bricks in the Making of Race and Place: Excavating a Lieu de Souvenir in New Orleans

2020 ◽  
Vol 70 (1) ◽  
pp. 7-32
Author(s):  
Angel Adams Parham
Keyword(s):  
New Orleans ◽  
Social Relationships ◽  
Cultural Practices ◽  
Building Blocks ◽  
The Past ◽  
Time Periods ◽  
Key Aspects ◽  
The City ◽  
Race And Place

This essay facilitates a multi-dimensional immersion into the life and rhythms of New Orleans, an entrée to the past that equips us to better understand the present and, from there, critically and creatively to envision our possible futures together. We explore the Faubourg Tremé by traversing layers of its lieux de souvenir - places of remembering, a concept inspired by but distinct from Pierre Nora’s lieux de mémoire - across three time periods. Each lieu de souvenir we visit from 1720 to the present will highlight material and symbolic foundations in Tremé that help us to understand key aspects of New Orleans’s past and present. The object that will guide our travel and meditation through each layer is the lowly but highly serviceable brick. At a purely material level, bricks are the literal building blocks of the city. Roads were paved with them and homes and other buildings were constructed with bricks as well. And at a symbolic level, bricks carry multiple rich and complex significations: Who makes them? How does their manufacturing shape the lives of the laborers who create them? Who buys them, and who profits from their sale? Tracing the brick and its uses throughout each lieu de souvenir sheds light on key social relationships, inequalities, and cultural practices that form the foundation of New Orleans’s past and present.

Molecular Biology of Vertebrate Olfactory Receptors and Circuits

2021 ◽  
Author(s):  
Richard P. Tucker ◽  
Qizhi Gong
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Olfactory Bulb ◽  
Gene Family ◽  
Sensory Neuron ◽  
Sensory Neurons ◽  
Odorant Receptor ◽  
Vomeronasal Organ ◽  
Odorant Receptors ◽  
The Central Nervous System

Animals use their olfactory system for the procurement of food, the detection of danger, and the identification of potential mates. In vertebrates, the olfactory sensory neuron has a single apical dendrite that is exposed to the environment and a single basal axon that projects to the central nervous system (i.e., the olfactory bulb). The first odorant receptors to be discovered belong to an enormous gene family encoding G protein-coupled seven transmembrane domain proteins. Odorant binding to these classical odorant receptors initiates a GTP-dependent signaling cascade that uses cAMP as a second messenger. Subsequently, additional types of odorant receptors using different signaling pathways have been identified. While most olfactory sensory neurons are found in the olfactory sensory neuroepithelium, others are found in specialized olfactory subsystems. In rodents, the vomeronasal organ contains neurons that recognize pheromones, the septal organ recognizes odorant and mechanical stimuli, and the neurons of the Grüneberg ganglion are sensitive to cool temperatures and certain volatile alarm signals. Within the olfactory sensory neuroepithelium, each sensory neuron expresses a single odorant receptor gene out of the large gene family; the axons of sensory neurons expressing the same odorant receptor typically converge onto a pair of glomeruli at the periphery of the olfactory bulb. This results in the transformation of olfactory information into a spatially organized odortopic map in the olfactory bulb. The axons originating from the vomeronasal organ project to the accessory olfactory bulb, whereas the axons from neurons in the Grüneberg ganglion project to 10 specific glomeruli found in the caudal part of the olfactory bulb. Within a glomerulus, the axons originating from olfactory sensory neurons synapse on the dendrites of olfactory bulb neurons, including mitral and tufted cells. Mitral cells and tufted cells in turn project directly to higher brain centers (e.g., the piriform cortex and olfactory tubercle). The integration of olfactory information in the olfactory cortices and elsewhere in the central nervous system informs and directs animal behavior.

scholarly journals The cell biology of smell

2010 ◽  
Vol 191 (3) ◽  
pp. 443-452 ◽  
Author(s):  
Shannon DeMaria ◽  
John Ngai
Keyword(s):  
Olfactory System ◽  
Cell Biology ◽  
Odorant Receptor ◽  
Large Family ◽  
G Protein Coupled Receptors ◽  
Odorant Receptors ◽  
Chemical Structures ◽  
Wide Range ◽  
G Protein Coupled ◽  
The Brain

The olfactory system detects and discriminates myriad chemical structures across a wide range of concentrations. To meet this task, the system utilizes a large family of G protein–coupled receptors—the odorant receptors—which are the chemical sensors underlying the perception of smell. Interestingly, the odorant receptors are also involved in a number of developmental decisions, including the regulation of their own expression and the patterning of the olfactory sensory neurons' synaptic connections in the brain. This review will focus on the diverse roles of the odorant receptor in the function and development of the olfactory system.

Fruit Fly Fighters

2002 ◽  
Author(s):  
Bryan Cantrell ◽  
Blair Chadwick ◽  
Anna Cahill
Keyword(s):  
Public Relations ◽  
Emergency Response ◽  
Traffic Control ◽  
Market Access ◽  
Control Program ◽  
Fruit Fly ◽  
Control Points ◽  
Cd Rom ◽  
Key Aspects ◽  
Technical Achievement

The campaign to eradicate the papaya fruit fly from north Queensland has been widely acknowledged by international scientists as a significant technical achievement that equals any similar control program world-wide. Fruit Fly Fighters is a highly readable and practical account of the whole campaign from 1995 when the papaya fruit fly was first discovered until 1999 when eradication was formally declared. Key aspects covered include: The emergency response; Campaign management; The growers' perspective; Monitoring, eradication, data management; quarantine, traffic control points; market access for fruit from infected areas; public relations; and research and development. The operating manuals and other reports are in a CD-ROM that accompanies this book.

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