scholarly journals Correction: Modelling locust foraging: How and why food affects group formation

2021 ◽  
Vol 17 (12) ◽  
pp. e1009695
Author(s):  
Fillipe Georgiou ◽  
Jerome Buhl ◽  
J. E. F. Green ◽  
Bishnu Lamichhane ◽  
Ngamta Thamwattana
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Author(s):  
Heide Schatten ◽  
Neidhard Paweletz ◽  
Ron Balczon

To study the role of sulfhydryl group formation during cell cycle progression, mammalian tissue culture cells (PTK2) were exposed to 100¼M 2-mercaptoethanol for 2 to 6 h during their exponential phase of growth. The effects of 2-mercaptoethanol on centrosomes, chromosomes, microtubules, membranes and intermediate filaments were analyzed by transmission electron microscopy (TEM) and by immunofluorescence microscopy (IFM) methods using a human autoimmune antibody directed against centrosomes (SPJ), and a mouse monoclonal antibody directed against tubulin (E7). Chromosomes were affected most by this treatment: premature chromosome condensation was detected in interphase nuclei, and the structure in mitotic chromosomes was altered compared to control cells. This would support previous findings in dividing sea urchin cells in which chromosomes are arrested at metaphase while the centrosome splitting cycle continues. It might also support findings that certairt-sulfhydryl-blocking agents block cyclin destruction. The organization of the microtubule network was scattered probably due to a looser organization of centrosomal material at the interphase centers and at the mitotic poles.


1970 ◽  
pp. 39-47
Author(s):  
Nabil Abdo

The International Labour Organization in Beirut has been running a project in the Palestinian Camps of Nahr El Bared and Ein El Helweh entitled “Palestinian Women Economic Empowerment Initiative”. The project started in 2011 and targets lowincome Palestinian women entrepreneurs through a threefold strategy: giving out loans and grants to women business groups in order to expand their businesses; training women entrepreneurs to enhance their business skills; and building the capacity of support organizations in order to improve business development services for women entrepreneurs and training them to be formally certified to deliver business group formation training. The project builds on the potential of business groups in assuring the protection of Palestinian women entrepreneurs from risks through resilience, pooling of resources, and collective voice. The objectives are to assure a sustainable livelihood for Palestinian women entrepreneurs through supporting them in expanding their businesses beyond survivalist low-income activities


Author(s):  
Marco Castillo ◽  
Ragan Petrie ◽  
Maximo A. Torero
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Author(s):  
Giacomo Benati ◽  
Carmine Guerriero

Abstract We develop a theory of state formation shedding light on the rise of the first stable state institutions in Bronze Age Mesopotamia. Our analysis suggests that the mix of adverse production conditions and unforeseen innovations pushed groups favored by old technologies to establish the state by granting political and property rights to powerless individuals endowed with new and complementary skills. Through these reforms, the elite convinced the nonelite that a sufficient part of the returns on joint investments would be shared via public spending and, thus, to cooperate and accumulate a culture of cooperation. Different from the main alternative theories, we stress that: (1) group formation is heavily shaped by unforeseen shocks to the returns on both risk-sharing and innovation; (2) complementarity in group-specific skills, and not violence, is key determinant of state formation; (3) military, merchant and, especially, religious ranks favored state formation and culture accumulation.


Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 602
Author(s):  
Monisha Devi ◽  
Nityananda Sarma ◽  
Sanjib K. Deka

Cognitive radio (CR) has evolved as a novel technology for overcoming the spectrum-scarcity problem in wireless communication networks. With its opportunistic behaviour for improving the spectrum-usage efficiency, CR enables the desired secondary users (SUs) to dynamically utilize the idle spectrum owned by primary users. On sensing the spectrum to identify the idle frequency bands, proper spectrum-allocation mechanisms need to be designed to provide an effectual use of the radio resource. In this paper, we propose a single-sided sealed-bid sequential-bidding-based auction framework that extends the channel-reuse property in a spectrum-allocation mechanism to efficiently redistribute the unused channels. Existing auction designs primarily aim at maximizing the auctioneer’s revenue, due to which certain CR constraints remain excluded in their models. We address two such constraints, viz. the dynamics in spectrum opportunities and varying availability time of vacant channels, and formulate an allocation problem that maximizes the utilization of the radio spectrum. The auctioneer strategises winner determination based on bids collected from SUs and sequentially leases the unused channels, while restricting the channel assignment to a single-channel-multi-user allocation. To model the spectrum-sharing mechanism, we initially developed a group-formation algorithm that enables the members of a group to access a common channel. Furthermore, the spectrum-allocation and pricing algorithms are operated under constrained circumstances, which guarantees truthfulness in the model. An analysis of the simulation results and comparison with existing auction models revealed the effectiveness of the proposed approach in assigning the unexploited spectrum.


Author(s):  
Changhao Liang ◽  
Rwitajit Majumdar ◽  
Hiroaki Ogata

AbstractCollaborative learning in the form of group work is becoming increasingly significant in education since interpersonal skills count in modern society. However, teachers often get overwhelmed by the logistics involved in conducting any group work. Valid support for executing and managing such activities in a timely and informed manner becomes imperative. This research introduces an intelligent system focusing on group formation which consists of a parameter setting module and the group member visualization panel where the results of the created group are shown to the user and can be graded. The system supports teachers by applying algorithms to actual learning log data thereby simplifying the group formation process and saving time for them. A pilot study in a primary school mathematics class proved to have a positive effect on students’ engagement and affections while participating in group activities based on the system-generated groups, thus providing empirical evidence to the practice of Computer-Supported Collaborative Learning (CSCL) systems.


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