spatial constraints
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2021 ◽  
pp. 137-149
Author(s):  
Carla Martínez del Barrio

This article analyses Jean Rhys’ 1939 novel Good Morning, Midnight from the standpoint of spatial and gender theory. Firstly, it explores the portrayal of gendered spaces in the modern city. In order to do so, it examines how Sasha Jensen challenges spatial constraints but is then identified as a stranger to the social order. Secondly, a parallelism between the urban automatisation of production and the female body is established to explore how consumer culture affects Sasha. Finally, it examines how the influence that Sasha’s fractured subjectivity has on her social encounters, which situate her on a liminal space.


2021 ◽  
Vol 11 (1) ◽  
pp. 14
Author(s):  
Xintao Ma ◽  
Yuna Hu ◽  
Yongwei Liu

The factors affecting tourist behavior are complex and diverse, but research on its effect from a purely spatial perspective is still limited. The aim of this paper is to explore the dichotomous interaction between tourists and islands: the behavioral patterns of tourists in island destinations and the mechanisms by which island spaces constrain tourist behavior. This study uses fine-grained global positioning system (GPS) tracking data actively authorized and released by tourists. We empirically studied tourist behavior from a spatial constraint perspective and discovered the following: island space has a strong influence and constraining effect on tourist behavior; different spatial attributes have different constraining effects on tourist behavior; and people with different identities interact with different attributes of space to produce different spatial properties, resulting in a ‘harmony-contradiction’ model of spatial interaction. These findings are of great value in expanding the perspective of spatial constraints and exploring the interactions between people and land. They are also of great practical significance in promoting spatial planning synergy, facilitating the construction of high-quality island-based tourism destinations, and building a harmonious relationship between people and land.


Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 600
Author(s):  
Matthew S. K. Yeo ◽  
S. M. Bhagya P. Samarakoon ◽  
Qi Boon Ng ◽  
Yi Jin Ng ◽  
M. A. Viraj J. Muthugala ◽  
...  

False ceilings are often utilised in residential and commercial spaces as a way to contain and conceal necessary but unattractive building infrastructure, including mechanical, electrical, and plumbing services. Concealing such elements has made it difficult to perform periodic inspection safely for maintenance. To complement this, there have been increasing research interests in mobile robots in recent years that are capable of accessing hard-to-reach locations, thus allowing workers to perform inspections remotely. However, current initiatives are met with challenges arising from unstructured site conditions that hamper the robot’s productivity for false ceiling inspection. The paper adopts a top-down approach known as “Design for Robots”, taking into account four robot-inclusive design principles: activity, accessibility, safety, observability. Falcon, a class of inspection robots, was used as a benchmark to identify spatial constraints according to the four principles. Following this, a list of false ceiling design guidelines for each category are proposed.


2021 ◽  
Vol 14 (2) ◽  
pp. 9-39
Author(s):  
Rosaline Georgevna Agiamoh

Abstract Globalization metrics rank Moscow as an alpha global city and the second most populous city in Europe. The city’s rate of urbanization and population growth has increased over the past decade triggering outward urban sprawl and the attendant need for spatial development within the city’s suburb – the Moscow Region municipality. This study focuses on internal factors and trends facilitating the need for inter-municipal waste management cooperation between the Moscow metropolis and the Moscow Region municipality. The paper reviews the policies driving this partnership and the inter-sectoral network facilitating waste management. Partnership effectiveness is evaluated via a multi-indicator approach, alongside qualitative thematic analysis comprising public surveys and the review of legal, administrative and operational documents. The findings reveal that cooperation between the municipalities is primarily driven by the convergence of socio-cultural factors, common territorial boundaries, the provision of public utilities and urban spatial constraints.


2021 ◽  
Vol 8 ◽  
Author(s):  
Cheyenne N. Phillips ◽  
Shawn Schowe ◽  
Conner J. Langeberg ◽  
Namoos Siddique ◽  
Erich G. Chapman ◽  
...  

Understanding how oxidatively damaged RNA is handled intracellularly is of relevance due to the link between oxidized RNA and the progression/development of some diseases as well as aging. Among the ribonucleases responsible for the decay of modified (chemically or naturally) RNA is the exonuclease Xrn-1, a processive enzyme that catalyzes the hydrolysis of 5′-phosphorylated RNA in a 5′→3′ direction. We set out to explore the reactivity of this exonuclease towards oligonucleotides (ONs, 20-nt to 30-nt long) of RNA containing 8-oxo-7,8-dihydroguanosine (8-oxoG), obtained via solid-phase synthesis. The results show that Xrn-1 stalled at sites containing 8-oxoG, evidenced by the presence of a slower moving band (via electrophoretic analyses) than that observed for the canonical analogue. The observed fragment(s) were characterized via PAGE and MALDI-TOF to confirm that the oligonucleotide fragment(s) contained a 5′-phosphorylated 8-oxoG. Furthermore, the yields for this stalling varied from app. 5–30% with 8-oxoG located at different positions and in different sequences. To gain a better understanding of the decreased nuclease efficiency, we probed: 1) H-bonding and spatial constraints; 2) anti-syn conformational changes; 3) concentration of divalent cation; and 4) secondary structure. This was carried out by introducing methylated or brominated purines (m1G, m6,6A, or 8-BrG), probing varying [Mg2+], and using circular dichroism (CD) to explore the formation of structured RNA. It was determined that spatial constraints imposed by conformational changes around the glycosidic bond may be partially responsible for stalling, however, the results do not fully explain some of the observed higher stalling yields. We hypothesize that altered π-π stacking along with induced H-bonding interactions between 8-oxoG and residues within the binding site may also play a role in the decreased Xrn-1 efficiency. Overall, these observations suggest that other factors, yet to be discovered/established, are likely to contribute to the decay of oxidized RNA. In addition, Xrn-1 degraded RNA containing m1G, and stalled mildly at sites where it encountered m6,6A, or 8-BrG, which is of particular interest given that the former two are naturally occurring modifications.


2021 ◽  
Vol 8 (10) ◽  
Author(s):  
Travis Monk ◽  
André van Schaik

Evolutionary graph theory investigates how spatial constraints affect processes that model evolutionary selection, e.g. the Moran process. Its principal goals are to find the fixation probability and the conditional distributions of fixation time, and show how they are affected by different graphs that impose spatial constraints. Fixation probabilities have generated significant attention, but much less is known about the conditional time distributions, even for simple graphs. Those conditional time distributions are difficult to calculate, so we consider a close proxy to it: the number of times the mutant population size changes before absorption. We employ martingales to obtain the conditional characteristic functions (CCFs) of that proxy for the Moran process on the complete bipartite graph. We consider the Moran process on the complete bipartite graph as an absorbing random walk in two dimensions. We then extend Wald’s martingale approach to sequential analysis from one dimension to two. Our expressions for the CCFs are novel, compact, exact, and their parameter dependence is explicit. We show that our CCFs closely approximate those of absorption time. Martingales provide an elegant framework to solve principal problems of evolutionary graph theory. It should be possible to extend our analysis to more complex graphs than we show here.


2021 ◽  
Author(s):  
Paheli Desai-Chowdhry ◽  
Alexander Brummer ◽  
Van Savage

Neurons are connected by complex branching processes - axons and dendrites - that collectively process information for organisms to respond to their environment. Classifying neurons according to differences in structure or function is a fundamental part of neuroscience. Here, by constructing new biophysical theory and testing against our empirical measures of branching structure, we establish a correspondence between neuron structure and function as mediated by principles such as time or power minimization for information processing as well as spatial constraints for forming connections. Specifically, based on these principles, we use undetermined Lagrange multipliers to predict scaling ratios for axon and dendrite sizes across branching levels. We test our predictions for radius and length scale factors against those extracted from neuronal images, measured for cell types and species that range from insects to whales. Notably, our findings reveal that the branching of axons and peripheral nervous system neurons is mainly determined by time minimization, while dendritic branching is mainly determined by power minimization. Further comparison of different dendritic cell types reveals that Purkinje cell dendrite branching is constrained by material costs while motoneuron dendrite branching is constrained by conduction time delay over a range of species. Our model also predicts a quarter-power scaling relationship between conduction time delay and species body size, which is supported by experimental data and may help explain the emergence of hemispheric specialization in larger animals as a means to offset longer time delays.


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