scholarly journals Task Specialization in U.S. Cities from 1880 to 2000

2018 ◽  
Vol 17 (3) ◽  
pp. 754-798 ◽  
Author(s):  
Guy Michaels ◽  
Ferdinand Rauch ◽  
Stephen J Redding
Keyword(s):  
Task Specialization

scholarly journals Polymorphism and division of labour in a socially complex ant: neuromodulation of aggression in the Australian weaver ant, Oecophylla smaragdina

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150704 ◽  
Author(s):  
J. Frances Kamhi ◽  
Kelley Nunn ◽  
Simon K. A. Robson ◽  
James F. A. Traniello
Keyword(s):  
Social Systems ◽  
Division Of Labour ◽  
Oecophylla Smaragdina ◽  
Minor Worker ◽  
Task Specialization ◽  
Territorial Defence ◽  
Weaver Ant ◽  
Eusocial Insects ◽  
Worker Size ◽  
Pharmacological Manipulations

Complex social structure in eusocial insects can involve worker morphological and behavioural differentiation. Neuroanatomical variation may underscore worker division of labour, but the regulatory mechanisms of size-based task specialization in polymorphic species are unknown. The Australian weaver ant, Oecophylla smaragdina , exhibits worker polyphenism: larger major workers aggressively defend arboreal territories, whereas smaller minors nurse brood. Here, we demonstrate that octopamine (OA) modulates worker size-related aggression in O. smaragdina . We found that the brains of majors had significantly higher titres of OA than those of minors and that OA was positively and specifically correlated with the frequency of aggressive responses to non-nestmates, a key component of territorial defence. Pharmacological manipulations that effectively switched OA action in major and minor worker brains reversed levels of aggression characteristic of each worker size class. Results suggest that altering OA action is sufficient to produce differences in aggression characteristic of size-related social roles. Neuromodulators therefore may generate variation in responsiveness to task-related stimuli associated with worker size differentiation and collateral behavioural specializations, a significant component of division of labour in complex social systems.

scholarly journals Collecting large datasets of rotational electron diffraction with ParallEM and SerialEM

2020 ◽  
Author(s):  
Kiyofumi Takaba ◽  
Saori Maki-Yonekura ◽  
Koji Yonekura
Keyword(s):  
Electron Diffraction ◽  
Data Collection ◽  
Large Scale ◽  
General Purpose ◽  
Task Specialization ◽  
Camera Control ◽  
Combined Use ◽  
Electron Microscopes ◽  
Diffraction Patterns ◽  
Automated Protocol

AbstractA semi-automated protocol has been developed for rotational data collection of electron diffraction patterns by combined use of SerialEM and ParallEM, where SerialEM is used for positioning of sample crystals and ParallEM for rotational data collection. ParallEM calls standard camera control software through an AutoIt script, which adapts to software operational changes and to new GUI programs guiding other cameras. Development included periodic flashing and pausing of data collection during overnight or day-long recording with a cold field-emission beam. The protocol proved to be efficient and accurate in data collection of large-scale rotational series from two JEOL electron microscopes, a general-purpose JEM-2100 and a high-end CRYO ARM 300. Efficiency resulted from simpler steps and task specialization. It is possible to collect 12–20 rotational series from ∼ −68º to ∼ 68º at a rotation speed of 1º /s in one hour without human supervision.

scholarly journals Can morphological and behavioral traits predict the foraging and feeding dynamics of social arachnids?

2020 ◽  
Author(s):  
Renan F Moura ◽  
Everton Tizo-Pedroso ◽  
Kleber Del-Claro
Keyword(s):  
Natural Selection ◽  
Social Insect ◽  
Prey Capture ◽  
Insect Species ◽  
Task Specialization ◽  
Behavioral Traits ◽  
The Social

Abstract Complex social insect species exhibit task specialization mediated by morphological and behavioral traits. However, evidence of such traits is scarce for other social arthropods. We investigated whether the social pseudoscorpion Paratemnoides nidificator exhibits morphologically and behaviorally specialized individuals in prey capture. We measured body and chela sizes of adult pseudoscorpions and analyzed predation processes. Larger individuals spent more time moving through the colony and foraging than smaller pseudoscorpions. Individuals that captured prey had increased body and absolute chelae sizes. Although larger individuals had relatively small chelae size, they showed a higher probability of prey capture. Larger individuals manipulated prey often, although they fed less than smaller pseudoscorpions. Individuals that initiated captures fed more frequently and for more time than the others. Natural selection might be favoring individuals specialized in foraging and colony protection, allowing smaller and less efficient adults to avoid contact with dangerous prey. To our knowledge, there is incipient information regarding specialized individuals in arachnids, and our results might indicate the emergence of a morphologically specialized group in this species.

How Do Women and Men Use Extra Time? Housework and Childcare after the French 35-Hour Workweek Regulation

2019 ◽  
Vol 35 (6) ◽  
pp. 807-824 ◽  
Author(s):  
Ariane Pailhé ◽  
Anne Solaz ◽  
Arthur Souletie
Keyword(s):  
Time Use ◽  
Time Allocation ◽  
Task Specialization ◽  
Exogenous Shock ◽  
Men And Women ◽  
Extra Time ◽  
Time Use Survey ◽  
Time Availability ◽  
Day Of The Week ◽  
Partial Implementation

Abstract This paper analyses how and when men and women devote their extra time to childcare and housework by exploiting an exogenous shock in scheduling: the partial implementation of the 35-hour workweek reform in France. Using propensity score matching and the most recent time use survey (INSEE, 2010), we show that time reallocations differ by gender and day of the week. While men dedicate their extra time to performing more housework on weekdays in the form of mainly time-flexible tasks such as repairs or shopping, they do less on weekends. This shift from weekends to weekdays is not observed for women who perform day-to-day tasks that are less transferable. Women spend more time on childcare and reduce multitasking. Overall, task specialization by gender is more pronounced, and this gendered use of similar extra time illustrates that time allocation is not only a question of time availability. In particular, men and women ‘do gender’ at weekends, when performing tasks is more visible to others.

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