Causes and consequences of inbreeding in the ant Formica exsecta

Human actions cause destruction and fragmentation of natural habitats, predisposing populations to loss of genetic diversity and inbreeding, which may further decrease their fitness and survival. Understanding these processes is a main concern in conservation genetics. Yet data from natural populations is scarce, particularly on invertebrates, owing to difficulties in measuring both fitness and inbreeding in the wild. Ants are social insects, and a prime example of an ecologically important group for which the effects of inbreeding remain largely unstudied. Social insects serve key roles in all terrestrial ecosystems, and the division of labor between the females in the colonies queens reproduce, workers tend to the developing brood probably is central to their ecological success. Sociality also has important implications for the effects of inbreeding. Despite their relative abundance, the effective population sizes of social insects tend to be small, owing to the low numbers of reproductive individuals relative to the numbers of sterile workers. This may subject social insects to loss of genetic diversity and subsequent inbreeding depression. Moreover, both the workers and queens can be inbred, with different and possibly multiplicative consequences. The aim of this study was to investigate causes and consequences of inbreeding in a natural population of ants. I used a combination of long-term field and genetic data from colonies of the narrow-headed ant Formica exsecta to examine dispersal, mating behavior and the occurrence of inbreeding, and its consequences on individual and colony traits. Mating in this species takes place in nuptial flights that have been assumed to be population-wide and panmictic. My results, however, show that dispersal is local, with queens establishing new colonies as close as 60 meters from their natal colony. Even though actual sib-mating was rare, individuals from different but related colonies pair, which causes the population to be inbred. Furthermore, multiple mates of queens were related to each other, which also indicates localized mating flights. Hence, known mechanisms of inbreeding avoidance, dispersal and multiple mating, were not effective in this population, as neither reduced inbreeding level of the future colony. Inbreeding had negative consequences both at the individual and colony level. A queen that has mated with a related male produces inbred workers, which impairs the colony s reproductive success. The inbred colonies were less productive and, specifically, produced fewer new queens, possibly owing to effects of inbreeding on the caste determination of female larvae. A striking finding was that males raised in colonies with inbred workers were smaller, which reflects an effect of the social environment as males, being haploid, cannot be inbred themselves. The queens produced in the inbred colonies, in contrast, were not smaller, but their immune response was up-regulated. Inbreeding had no effect on queen dispersal, but inbred queens had a lower probability of successfully founding a new colony. Ultimately, queens that survived through the colony founding phase had a shorter lifespan. This supports the idea that inbreeding imposes a genetic stress, leading to inbreeding depression on both the queen and the colony level. My results show that inbreeding can have profound consequences on insects in the wild, and that in social species the effects of inbreeding may be multiplicative and mediated through the diversity of the social environment, as well as the genetic makeup of the individuals themselves. This emphasizes the need to take into account all levels of organization when assessing the effects of genetic diversity in social animals.

Load-Deflection Behavior of Restrained R/C Skew Slabs

A method is presented for determining the complete load-deflection behavior of reinforced concrete skew slabs restrained at the edges and subjected to uniformly-distributed loading. The analysis is considered in three stages. In the first stage the load-deflection behavior up to the cracking load is considered. The behavior between the cracking load and the yield line load is considered in the second stage. The load-deflection behavior beyond the yield line load, taking into account the effect of the membrane action, is considered in the third stage. Details of an experimental program of casting and testing 12 reinforced concrete skew slabs restrained at the edges are presented to verify the results of the analysis.

Should I stay or should I go? : Reproductive and dispersal strategies of site-specific liverwort species

The area of intensively managed forests, in which required conditions for several liverwort species are seldom found, has expanded over the forest landscape during the last century. Liverworts are very sensitive to habitat changes, because they demand continuously moist microclimate. Consequently, about third of the forest liverworts have been classified as threatened or near threatened in Finland. The general objective of this thesis is to increase knowledge of the reproductive and dispersal strategies of the substrate-specific forest bryophytes. A further aim was to develop recommendations for conservation measures for species inhabiting unstable and stable habitats in forest landscape. Both population ecological and genetic methods have been applied in the research. Anastrophyllum hellerianum inhabits spatially and temporally limited substrate patches, decaying logs, which can be considered as unstable habitats. The results show that asexual reproduction by gemmae is the dominant mode of reproduction, whereas sexual reproduction is considerably infrequent. Unlike previously assumed, not only spores but also the asexual propagules may contribute to long-distance dispersal. The combination of occasional spore production and practically continuous, massive gemma production facilitates dispersal both on a local scale and over long distances, and it compensates for the great propagule losses that take place preceding successful establishment at suitable sites. However, establishment probability of spores may be restricted because of environmental and biological limitations linked to the low success of sexual reproduction. Long-lasting dry seasons are likely to result in a low success of sexual reproduction and decreased release rate of gemmae from the shoots, and consequent fluctuations in population sizes. In the long term, the substratum limitation is likely to restrict population sizes and cause local extinctions, especially in small-sized remnant populations. Contrastingly, larger forest fragments with more natural disturbance dynamics, to which the species is adapted, are pivotal to species survival. Trichocolea tomentella occupies stable spring and mesic habitats in woodland. The relatively small populations are increasingly fragmented with a high risk for extinction for extrinsic reasons. The results show that T. tomentella mainly invests in population persistence by effective clonal growth via forming independent ramets and in competitive ability, and considerably less in sexuality and dispersal potential. The populations possess relatively high levels of genetic diversity regardless of population size and of degree of isolation. Thus, the small-sized populations inhabiting stable habitats should not be neglected when establishing conservation strategies for the species and when considering the habitat protection of small spring sites. Restricted dispersal capacity, also on a relatively small spatial scale, is likely to prevent successful (re-)colonization in the potential habitat patches of recovering forest landscapes. By contrast, random short-range dispersal of detached vegetative fragments within populations at suitable habitat seems to be frequent. Thus, the restoration actions of spring and streamside habitats close to the populations of T. tomentella may contribute to population expansion. That, in turn, decreases the harmful effects of environmental stochasticity.

I know what you did this summer: Users' behavior on internet

Human age is surrounded by assumed set of rules and behaviors imposed by local culture and the society they live in. This paper introduces software that counts the presence of a person on the Internet and examines the activities he/she conducts online. The paper answers questions such as how "old" are you on the Internet? How soon will a newbie be exposed to adult websites? How long will it take for a new Internet user to know about social networking sites? And how many years a user has to surf online to celebrate his/her first "birthday" of Internet presence? Paper findings from a database of 105 school and university students containing their every click of first 24 hours of Internet usage are presented. The findings provide valuable insights for Internet Marketing, ethics, Internet business and the mapping of Internet life with real life. Privacy and ethical issues related to the study have been discussed at the end. © Springer Science+Business Media B.V. 2010.

Influencing customers through customers: Simulation of herd behavior in supermarkets

This work proposes a supermarket optimization simulation model called Swarm-Moves is based on self organized complex system studies to identify parameters and their values that can influence customers to buy more on impulse in a given period of time. In the proposed model, customers are assumed to have trolleys equipped with technology like RFID that can aid the passing of products' information directly from the store to them in real-time and vice-versa. Therefore, they can get the information about other customers purchase patterns and constantly informing the store of their own shopping behavior. This can be easily achieved because the trolleys "know" what products they contain at any point. The Swarm-Moves simulation is the virtual supermarket providing the visual display to run and test the proposed model. The simulation is also flexible to incorporate any given model of customers' behavior tailored to particular supermarket, settings, events or promotions. The results, although preliminary, are promising to use RFID technology for marketing products in supermarkets and provide several dimensions to look for influencing customers via feedback, real-time marketing, target advertisement and on-demand promotions. ©2009 IEEE.

The effects of eutrophication on alternative reproductive tactics in threespine sticklebacks

When organisms compete for mates and fertilisations, the process of sexual selection drives the evolution of traits that increase reproductive success. The traits targeted by selection, and the extent to which they change, are constrained by the local environment. Sexual selection due to female mate choice can be undermined by alternative reproductive tactics (ARTs), which refers to discontinuous variation in traits or behaviours used in reproduction. As human activities are rapidly changing our planet, this raises the question how ARTs will be affected. Fish show a bewildering diversity of ARTs, which make them good model organisms to answer these questions. One example of human-induced environmental change, which is affecting aquatic ecosystems around the world, is eutrophication, the over-enrichment of water bodies with nutrients. One of its effects is decreased underwater visibility due to increases in both turbidity and vegetation density. The aims of this thesis were to investigate the effects increased turbidity and vegetation density have on an ART in sticklebacks, a fish common to marine and fresh water bodies of the Northern hemisphere. I furthermore investigated how this affected sexual selection for male size, a trait commonly under selection. I used a combination of behavioural observations in microcosms, where I manipulated underwater visibility, with collection of genetic material to reconstruct parentage of broods, and thus identify sneak fertilisations. The results show that turbidity might have weak negative effects on the frequency of sneaking behaviour, although this behaviour was rather infrequent in these experiments, which complicates firm conclusions. In dense vegetation the number of sneak fertilisations decreased slightly, as fewer nesting males sneaked, while the number of non-nesting males sneaking remained constant. The paternity analyses revealed that a significantly smaller fraction of eggs was sneak fertilised under dense vegetation. Furthermore, amongst the nesting males that sneaked, the amount of eggs sneak fertilised correlated positively with courtship success. A reduction in sneaking by these males under dense vegetation equalised the distribution of fertilisation success, in turn contributing to a decrease in the opportunity for selection. Under dense vegetation significantly more males built nests, which has also been observed in previous field studies. In a separate experiment we addressed if such changes in the proportion of nesters and non-nesters, without changes in visibility, affected the incidence of sneak fertilisation. My results show this was not the case, likely because sneaking is an opportunistic tactic shown by both nesters and non-nesters. Non-nesters did sneak proportionately more when there were many of them, which could be due to changes in the cost-benefit ratio of sneaking. As nesters can only attack one intruder at a time, the costs and risks per sneaker will decrease as the number of sneakers increases. The defensive behaviours shown by the nesters before spawning shifted to a more aggressive form of nest defence. This could be because less aggressive behaviours lose their effectiveness when the number of intruders increases. It could also indicate that the risks associated with aggressive behaviours decrease when there are fewer fellow nesters, as other studies indicate nesters are competitive and aggressive individuals. Under turbid conditions I did not detect changes in the opportunity for selection, based on fertilisation success, nor was male size under significant selection under clear or turbid conditions. More thorough analyses under densely vegetated conditions across the nesting, courtship and fertilisation stages revealed a decrease in the opportunity for selection across all stages. A reduction in sneaking by nesters contributed to this. During the nesting stage, but not during later stages, body size was under significant directional selection under sparse, but not dense vegetation. This illustrates the importance of considering all selection stages to get a complete picture of how environmental changes affect sexual selection. Leaving out certain stages or subgroups can result in incomplete or misleading results.

Glutamatergic Modulation of Cue-Induced Drug-Seeking Behavior in the Rat

The characteristics of drug addiction include compulsive drug use despite negative consequences and re-occurring relapses, returns to drug use after a period of abstinence. Therefore, relapse prevention is one of the major challenges for the treatment of drug addiction. There are three main factors capable of inducing craving for drugs and triggering relapse long after cessation of drug use and dissipation of physical withdrawal signs: stress, re-exposure to the drug, and environmental stimuli (cues) that have been previously associated with drug use. The neurotransmitters dopamine and glutamate have been implicated in the modulation of drug-seeking behavior. The aim of this project was to examine the role of glutamatergic neurotransmission in relapse triggered by conditioned drug-associated stimuli. The focus was on clarifying whether relapse to drug seeking can be attenuated by blockade of glutamate receptors. In addition, as the nucleus accumbens has been proposed to participate in the modulation of drug-seeking behavior, the effects of glutamate receptor blockade in this brain structure on cue-induced relapse were investigated. The studies employed animals models in which rats were trained to press a lever in a test cage to obtain alcohol or intravenous cocaine. Drug availability was paired with distinct olfactory, auditory, or visual stimuli. This phase was followed by extinction training, during which lever presses did not result in the presentation of the drug or the drug-associated stimuli. Extinction training led to a gradual decrease in the number of lever presses during test sessions. Relapse was triggered by presenting the rats with the drug-associated stimuli in the absence of alcohol or cocaine. The drug-associated stimuli were alone capable of inducing resumption of lever pressing and maintaining this behavior during repeated testing. The number of lever presses during a session represented the intensity of drug-seeking and relapse behavior. The results suggest that glutamatergic neurotransmission is involved in the modulation of drug-seeking behavior. Both alcohol and cocaine relapse were attenuated by systemic pretreatment with glutamate receptor antagonists. However, differences were found in the ability of ionotropic AMPA/kainate and NMDA receptor antagonists to regulate drug-seeking behavior. The AMPA/kainate antagonists CNQX and NBQX, and L-701,324, an antagonist with affinity for the glycine site of the NMDA receptor, attenuated cue-induced drug seeking, whereas the competitive NMDA antagonist CGP39551 and the NMDA channel blocker MK-801 were without effect. MPEP, an antagonist at metabotropic mGlu5 glutamate receptors, also decreased drug seeking, but its administration was found to lead to conditioned suppression of behavior during subsequent treatment sessions, suggesting that MPEP may have undesirable side effects. The mGluR2/3 agonist LY379268 and the mGluR8 agonist (S)-3,4-DCPG decreased both cue-induced relapse to alcohol drinking and alcohol consumption. Control experiments showed however that administration of the agonists was accompanied by motor suppression limiting their usefulness. Administration of the AMPA/kainate antagonist CNQX, the NMDA antagonist D-AP5, and the mGluR5 antagonist MPEP into the nucleus accumbens resulted also in a decrease in drug-seeking behavior, suggesting that the nucleus accumbens is at least one of the anatomical sites regulating drug seeking and mediating the effects of glutamate receptor antagonists on this behavior.

Cooperation and conflict in conspecific brood parasitism : an alternative reproductive tactic

Interactions among individuals give rise to both cooperation and conflict. Individuals will behave selfishly or altruistically depending on which gives the higher payoff. The reproductive strategies of many animals are flexible and several alternative tactics may be present from which the most suitable one is applied. Generally, alternative reproductive tactics may be defined as a response to competition from individuals of the same sex. These alternative reproductive tactics are means by which individuals may fine-tune their fitness to the reigning circumstances and which are shaped by the environment individuals are occupying as well as by the behaviour of other individuals sharing the environment. By employing such alternative ways of achieving reproductive output, individuals may alleviate competition from others. Conspecific brood parasitism (CBP) is an alternative reproductive strategy found in several egg laying animal groups, and it is especially common among waterfowl. Within this alternative reproductive strategy, four reproductive options can be identified. These four options represent a continuum from low reproductive effort coupled with low fitness returns, to high reproductive effort and consequently high benefits. It may not be evident how individuals should allocate reproductive effort between eggs laid in their own nest vs. in nests of others, however. Limited fecundity will constrain the number of eggs donated by a parasite, but also the tendency for hosts to accept parasitic eggs may affect the allocation decision. Furthermore, kinship, individual quality and the costs of breeding may play a role in complicating the allocation decision. In this thesis, I view the seemingly paradoxical effects of kinship on conflict resolution in the context of alternative reproductive tactics, examining the resulting features of cooperation and conflict. Conspecific brood parasitism sets the stage for investigating these questions. By using both empirical and theoretical approaches, I examine the nature of CBP in a brood parasitic duck, the Barrow's goldeneye (Bucephala islandica). The theoretical chapter of this thesis gives rise to four main conclusions. Firstly, variation in individual quality plays a central role in shaping breeding strategies. Secondly, kinship plays a central role in the evolution of CBP. Thirdly, egg recognition ability may affect the prevalence of parasitism. If egg recognition is perfect, higher relatedness between host and parasite facilitates CBP. Finally, I show that the relative costs of egg laying and post-laying care play a so far underestimated role in determining the prevalence of parasitism. The costs of breeding may outweigh possible inclusive fitness benefits accrued from receiving eggs from relatives. Several of the patterns brought out by the theoretical work are then confirmed empirically in the following chapters. Findings include confirmation of the central role of relatedness in determining the extent of parasitism as well as inducing a counterintuitive host clutch reduction. Furthermore, I demonstrate a cost of CBP inflicted on hosts, as well as results suggesting that host age reflects individual quality, affecting the ability to overcome costs inflicted by CBP. In summary, I demonstrate both theoretically and empirically the presence of cooperation and conflict in the interactions between conspecific parasites and their hosts. The field of CBP research has traditionally been divided, but the first steps have now been taken toward the acceptance of the opposite side of the divide. Especially the theoretical findings of chapter 1 offer the possibility to view seemingly contrasting results of various studies within the same framework, and may direct future research toward more general features underlying differences in the patterns of CBP between populations or species.

Kin selection, social polymorphism, and reproductive allocation in ants

Social groups are common across animal species. The reasons for grouping are straightforward when all individuals gain directly from cooperating. However, the situation becomes more complex when helping entails costs to the personal reproduction of individuals. Kin selection theory has offered a fruitful framework to explain such cooperation by stating that individuals may spread their genes not only through their own reproduction, but also by helping related individuals reproduce. However, kin selection theory also implicitly predicts conflicts when groups consist of non-clonal individuals, i.e. relatedness is less than one. Then, individual interests are not perfectly aligned, and each individual is predicted to favour the propagation of their own genome over others. Social insects provide a solid study system to study the interplay between cooperation and conflict. Breeding systems in social insects range from solitary breeding to eusocial colonies displaying complete division of reproduction between the fertile queen and the sterile worker caste. Within colonies, additional variation is provided by the presence of several reproductive individuals. In many species, the queen mates multiply, which causes the colony to consist of half-sib instead of full-sib offspring. Furthermore, in many species colonies contain multiple breeding queens, which further dilutes relatedness between colony members. Evolutionary biology is thus faced with the challenge to answer why such variation in social structure exists, and what the consequences are on the individual and population level. The main part of this thesis takes on this challenge by investing the dynamics of socially polymorphic ant colonies. The first four chapters investigate the causes and consequences of different social structures, using a combination of field studies, genetic analyses and laboratory experiments. The thesis ends with a theoretical chapter focusing on different social interactions (altruism and spite), and the evolution of harming traits. The main results of the thesis show that social polymorphism has the potential to affect the behaviour and traits of both individuals and colonies. For example, we found that genetic polymorphism may increase the phenotypic variation between individuals in colonies, and that socially polymorphic colonies may show different life history patterns. We also show that colony cohesion may be enhanced even in multiple-queen colonies through patterns of unequal reproduction between queens. However, the thesis also demonstrates that spatial and temporal variation between both populations and environments may affect individual and colony traits, to the degree that results obtained in one place or at one time may not be applicable in other situations. This opens up potential further areas of research to explain these differences.

Palladium(II) and platinum(II) complexes of beta-functionalized ethyl selenolates: Effect of substitution on synthesis, reactivity, spectroscopy, structures and thermal behavior

Sodium ethylselenolates with functional groups X (where X = -OH, -COOH, -COOMe and -COOEt) at beta-carbon were prepared in situ by reductive cleavage of corresponding diselenide with NaBH4 either in methanol or aqueous ammonia. Treatment of these selenolates with [M2Cl2(mu-Cl)(2)(PR'(3))(2)] (M = Pd or Pt; PR'(3) = PMePh2, PnPr(3)) in different stoichiometry yielded various bi- and tri-nuclear complexes. The homoleptic hexanuclear complexes [Pd(mu-SeCH2CH2X)(2)](6) (X = OH, COOH, COOEt), were obtained by reacting Na2PdCl4 with NaSeCH2CH2X. All these complexes have been fully characterized. Molecular structures of ethylselenolates containing hydroxyl and carboxylic acid groups revealed solid state associated structures through inter-molecular hydrogen bond interactions. Trinuclear complex, [Pd3Cl2(mu-SeCH2CH2COOH)(4)(PnPr(3))(2)] (3a), was disposed in a boat form unlike chair conformation observed for the corresponding methylester complex. The effect of beta-functionality in ethylselenolate ligands towards reactivity, structures and thermal properties of palladium and platinum complexes has been extensively Studied.

Cellular Automata Models of Traffic Behavior in Presence of Speed Breaking Structures

In this article, we study traffic flow in the presence of speed breaking structures. The speed breakers are typically used to reduce the local speed of vehicles near certain institutions such as schools and hospitals. Through a cellular automata model we study the impact of such structures on global traffic characteristics. The simulation results indicate that the presence of speed breakers could reduce the global flow under moderate global densities. However, under low and high global density traffic regime the presence of speed breakers does not have an impact on the global flow. Further the speed limit enforced by the speed breaker creates a phase distinction. For a given global density and slowdown probability, as the speed limit enforced by the speed breaker increases, the traffic moves from the reduced flow phase to maximum flow phase. This underlines the importance of proper design of these structures to avoid undesired flow restrictions.

The trishanku gene and terminal morphogenesis in Dictyostelium discoideum

P>Multicellular development in the social amoeba Dictyostelium discoideum is triggered by starvation. It involves a series of morphogenetic movements, among them being the rising of the spore mass to the tip of the stalk. The process requires precise coordination between two distinct cell types-presumptive (pre-) spore cells and presumptive (pre-) stalk cells. Trishanku (triA) is a gene expressed in prespore cells that is required for normal morphogenesis. The triA- mutant shows pleiotropic effects that include an inability of the spore mass to go all the way to the top. We have examined the cellular behavior required for the normal ascent of the spore mass. Grafting and mixing experiments carried out with tissue fragments and cells show that the upper cup, a tissue that derives from prestalk cells and anterior-like cells (ALCs), does not develop properly in a triA- background. A mutant upper cup is unable to lift the spore mass to the top of the fruiting body, likely due to defective intercellular adhesion. If wild-type upper cup function is provided by prestalk and ALCs, trishanku spores ascend all the way. Conversely, Ax2 spores fail to do so in chimeras in which the upper cup is largely made up of mutant cells. Besides proving that under these conditions the wild-type phenotype of the upper cup is necessary and sufficient for terminal morphogenesis in D. discoideum, this study provides novel insights into developmental and evolutionary aspects of morphogenesis in general. Genes that are active exclusively in one cell type can elicit behavior in a second cell type that enhances the reproductive fitness of the first cell type, thereby showing that morphogenesis is a cooperative process.

An Experimental Study on Energy Absorption Behavior of Polyurethane Foams

This article is concerned with a study on the energy absorption behavior of polyurethane (PU) foams such as flexible high resilience (HR), flexible viscoelastic (VE) and semi-rigid (SR) foams as a function of the overall foam density. Foam samples were prepared in the form of cubes by mixing appropriate polyol and isocyanate compounds produced by Huntsman International India Pvt. Ltd. in varying proportions leading to a range of densities for each type of foam. The cubical samples were tested under compressive load in a standard UTM. Based on the measured load-displacement behaviors, variations of peak load and energy-absorption attributes with respect to density are plotted for each type of foam and the possible existence of an optimum foam density is shown.

The composition dependence of electrical switching behavior of Ge7Se93-xSbx glasses

Bulk Ge7Se93-xSbx (21 <= x <= 32) glasses are prepared by melt quenching method and electrical switching studies have been undertaken on these samples to elucidate the type of switching and the composition and thickness dependence of switching voltages. On the basis of the compressibility and atomic radii, it has been previously observed that Se-based glasses exhibit memory switching behavior. However, the present results indicate that Ge7Se93-xSbx glasses exhibit threshold type electrical switching with high switching voltages. Further, these samples are found to show fluctuations in the current-voltage (I-V) characteristics. The observed threshold behavior of Ge7Se93-xSbx glasses has been understood on the basis of larger atomic radii and lesser compressibilities of Sb and Ge. Further. the high switching voltages and fluctuations in the I-V characteristics of Ge-Se-Sb samples can be attributed to the high resistance of the samples and the difference in thermal conductivities of different structural units constituting the local structure of these glasses. The switching voltages of Ge7Se93-xSbx glasses have been found to decrease with the increase in the Sb concentration. The observed composition dependence of switching voltages has been understood on the basis of higher metallicity of the Sb additive and also in the light of the Chemically Ordered Network (CON) model. Further, the thickness dependence of switching voltages has been studied to reassert the mechanism of switching.