Acadia University

About: Acadia University is a education organization based out in Wolfville, Nova Scotia, Canada. It is known for research contribution in the topics: Population & Wireless sensor network. The organization has 1903 authors who have published 3881 publications receiving 90517 citations. The organization is also known as: Queen's College.

Relaxin gene family in teleosts: phylogeny, syntenic mapping, selective constraint, and expression analysis.

Abstract: In recent years, the relaxin family of signaling molecules has been shown to play diverse roles in mammalian physiology, but little is known about its diversity or physiology in teleosts, an infraclass of the bony fishes comprising ~ 50% of all extant vertebrates. In this paper, 32 relaxin family sequences were obtained by searching genomic and cDNA databases from eight teleost species; phylogenetic, molecular evolutionary, and syntenic data analyses were conducted to understand the relationship and differential patterns of evolution of relaxin family genes in teleosts compared with mammals. Additionally, real-time quantitative PCR was used to confirm and assess the tissues of expression of five relaxin family genes in Danio rerio and in situ hybridization used to assess the site-specific expression of the insulin 3-like gene in D. rerio testis. Up to six relaxin family genes were identified in each teleost species. Comparative syntenic mapping revealed that fish possess two paralogous copies of human RLN3, which we call rln3a and rln3b, an orthologue of human RLN2, rln, two paralogous copies of human INSL5, insl5a and insl5b, and an orthologue of human INSL3, insl3. Molecular evolutionary analyses indicated that: rln3a, rln3b and rln are under strong evolutionary constraint, that insl3 has been subject to moderate rates of sequence evolution with two amino acids in insl3/INSL3 showing evidence of positively selection, and that insl5b exhibits a higher rate of sequence evolution than its paralogue insl5a suggesting that it may have been neo-functionalized after the teleost whole genome duplication. Quantitative PCR analyses in D. rerio indicated that rln3a and rln3b are expressed in brain, insl3 is highly expressed in gonads, and that there was low expression of both insl5 genes in adult zebrafish. Finally, in situ hybridization of insl3 in D. rerio testes showed highly specific hybridization to interstitial Leydig cells. Contrary to previous studies, we find convincing evidence that teleosts contain orthologues of four relaxin family peptides. Overall our analyses suggest that in teleosts: 1) rln3 exhibits a similar evolution and expression pattern to mammalian RLN3, 2) insl3 has been subject to positive selection like its mammalian counterpart and shows similar tissue-specific expression in Leydig cells, 3) insl5 genes are highly represented and have a relatively high rate of sequence evolution in teleost genomes, but they exhibited only low levels of expression in adult zebrafish, 4) rln is evolving under very different selective constraints from mammalian RLN. The results presented here should facilitate the development of hypothesis-driven experimental work on the specific roles of relaxin family genes in teleosts.

A range-wide domino effect and resetting of the annual cycle in a migratory songbird.

Abstract: Latitudinal differences in timing of breeding are well documented but how such differences carry over to influence timing of events in the annual cycle of migratory birds is not well understood. We examined geographical variation in timing of events throughout the year using light-level geolocator tracking data from 133 migratory tree swallows ( Tachycineta bicolor) originating from 12 North American breeding populations. A swallow's breeding latitude influenced timing of breeding, which then carried over to affect breeding ground departure. This resulted in subsequent effects on the arrival and departure schedules at autumn stopover locations and timing of arrival at non-breeding locations. This 'domino effect' between timing events was no longer apparent by the time individuals departed for spring migration. Our range-wide analysis demonstrates the lasting impact breeding latitude can have on migration schedules but also highlights how such timing relationships can reset when individuals reside at non-breeding sites for extended periods of time.

AACK: Adaptive Acknowledgment Intrusion Detection for MANET with Node Detection Enhancement

Abstract: A Mobile Ad-hoc NETwork (MANET) is an infrastructureless network consisting of self-configuring mobile nodes connected by wireless links. Nodes rely on each other to store and forward packets. Most of the proposed MANET protocols assume cooperative and friendly network context, and do not address security issues. Furthermore, MANETs are highly vulnerable for passive and active attacks because of their open medium, rapidly changing topology, lack of centralized monitoring. Encryption and authentication solutions, which are considered as the first line of defense, are not sufficient to protect MANETs from packet dropping attacks. Most of the current Intrusion Detection Systems (IDSs) for MANETS rely on the Watchdog technique. In this research we study the behavior of this technique and propose a novel mechanism, named: Adaptive ACKnowledgment (AACK), for solving two significant problems: the limited transmission power and receiver collision. This mechanism is an enhancement to the TWOACK scheme where its detection overhead is reduced while the detection efficiency is increased. NS2 is used to simulate and evaluate the proposed scheme and compare it against the TWOACK and Watchdog methods. The obtained results show that the new AACK scheme outperforms both of the TWOACK and Watchdog methods in terms of network packet delivery ratio and routing overhead.

Reassembling Weber to reveal the-past-as-history in management and organization studies

Abstract: The purpose of this article is to unravel the link between the past and history to reveal the importance and the problems of developing a historically informed critical management studies (Booth and Rowlinson, 2006; Kieser, 1994). Drawing on Munslow (2010), we focus on the relationship between ‘the past’ and ‘history’ as ‘ontologically dissonant’ (p. 3) to argue for an ‘epistemically skeptical,’ relational approach to critical organizational history. These arguments are explored through analysis of the ‘career’ of Max Weber in management and organization studies (MOS).