Life Cycle Variation Research Articles

An analysis of the determinants of sports participation and time spent in different sporting contexts

ABSTRACTUsing data from a survey of Irish adults, this study analyses sport participation from the perspective of four different sporting contexts, organised training, organised competition, participating with friends and family and individual activities. The results reinforce the belief that different profiles of sports participants exist. Volunteers, club members and spectators at events are all more likely to be involved in organised sporting activities. City dwellers, highly educated individuals and individuals with disabilities are more likely to spend time in a sporting activity on their own. Gender and lifecycle variables are also important in determining the type of sport activity an individual undertakes. Income, whilst being a barrier to overall sport participation, does not surprisingly influence the choice of sporting context. A clear implication is that the funding and development of policies toward increased sports participation rates need to be designed in such a way to appeal to different sporting preferences.

Cross lifecycle variability analysis: Utilizing requirements and testing artifacts

Variability analysis is an essential activity that supports increasing and systemizing reuse across similar software products. Current studies use different types of artifacts for analyzing variability, most notably are architecture or design, requirements, and code. While architecture, design, and code help understand and model the differences in solutions and realizations, requirements enable capturing differences in a higher level of abstraction through the intended use of the software products or their behavior. However, analyzing variability based on requirements may result in inaccurate outcomes, due to the informal and incomplete nature of requirements. To tackle this deficiency, we call for augmenting requirements-based variability analysis with other behavior-related cross-lifecycle artifacts. Particularly, we extend an approach that compares and analyzes software behaviors based on requirements taking into account both ontological and semantic considerations. Using test cases and their relations to requirements, our extension, named SOVA R-TC, extract software behaviors more comprehensively, including their preconditions, post-conditions, and expected results. The outputs of SOVA R-TC are feature diagrams, which group similar behaviors and present variability of software products in a tree structure. Empirically evaluating outcomes of SOVA R-TC, they seem to be perceived as significantly better than outcomes generated based on requirements only.

Life cycle synchronization is a viral drug resistance mechanism.

Viral infections are one of the major causes of death worldwide, with HIV infection alone resulting in over 1.2 million casualties per year. Antiviral drugs are now being administered for a variety of viral infections, including HIV, hepatitis B and C, and influenza. These therapies target a specific phase of the virus’s life cycle, yet their ultimate success depends on a variety of factors, such as adherence to a prescribed regimen and the emergence of viral drug resistance. The epidemiology and evolution of drug resistance have been extensively characterized, and it is generally assumed that drug resistance arises from mutations that alter the virus’s susceptibility to the direct action of the drug. In this paper, we consider the possibility that a virus population can evolve towards synchronizing its life cycle with the pattern of drug therapy. The periodicity of the drug treatment could then allow for a virus strain whose life cycle length is a multiple of the dosing interval to replicate only when the concentration of the drug is lowest. This process, referred to as “drug tolerance by synchronization”, could allow the virus population to maximize its overall fitness without having to alter drug binding or complete its life cycle in the drug’s presence. We use mathematical models and stochastic simulations to show that life cycle synchronization can indeed be a mechanism of viral drug tolerance. We show that this effect is more likely to occur when the variability in both viral life cycle and drug dose timing are low. More generally, we find that in the presence of periodic drug levels, time-averaged calculations of viral fitness do not accurately predict drug levels needed to eradicate infection, even if there is no synchronization. We derive an analytical expression for viral fitness that is sufficient to explain the drug-pattern-dependent survival of strains with any life cycle length. We discuss the implications of these findings for clinically relevant antiviral strategies.

The Obscure World of Integrative and Mobilizable Elements, Highly Widespread Elements that Pirate Bacterial Conjugative Systems.

Conjugation is a key mechanism of bacterial evolution that involves mobile genetic elements. Recent findings indicated that the main actors of conjugative transfer are not the well-known conjugative or mobilizable plasmids but are the integrated elements. This paper reviews current knowledge on “integrative and mobilizable elements” (IMEs) that have recently been shown to be highly diverse and highly widespread but are still rarely described. IMEs encode their own excision and integration and use the conjugation machinery of unrelated co-resident conjugative element for their own transfer. Recent studies revealed a much more complex and much more diverse lifecycle than initially thought. Besides their main transmission as integrated elements, IMEs probably use plasmid-like strategies to ensure their maintenance after excision. Their interaction with conjugative elements reveals not only harmless hitchhikers but also hunters that use conjugative elements as target for their integration or harmful parasites that subvert the conjugative apparatus of incoming elements to invade cells that harbor them. IMEs carry genes conferring various functions, such as resistance to antibiotics, that can enhance the fitness of their hosts and that contribute to their maintenance in bacterial populations. Taken as a whole, IMEs are probably major contributors to bacterial evolution.

Nuisance Didymosphenia geminata blooms in the Argentinean Patagonia: Status and current research trends

Large nuisance blooms of Didymosphenia geminata have become increasingly widespread in Patagonia. Although the first published account for South America was in 1964, reports of large growths in Chile and Argentina commenced around 2010. Since then, these blooms have been observed all along the Andes region to the south of parallel 42°S. General surveys are needed to help provide an explanation. Possibilities include one or more new genetic variants or responses of local populations to global environmental changes. Electron microscopy of material from the Argentinean Patagonia revealed marked differences between regions, though it is unclear how much local factors and/or variations in life cycle contribute. Thus, we are approaching the problem from a molecular perspective, which we hope will help to overcome this limitation. Initial studies showed that D. geminata seems to be highly recalcitrant to DNA extraction, thus hindering the survey of molecular markers. We have now developed an improved DNA extraction technique for Didymosphenia mats, which markedly outperforms other techniques. However, endpoint polymerase chain reaction analyses suggest the persistence of polymerase chain reaction inhibitors in the samples, highlighting the need of further improvements for quantitative studies.

Genetic Evidence for Sexuality in Cochliopodium (Amoebozoa).

Microbial eukaryotes, including amoeboids, display diverse and complex life cycles that may or may not involve sexual reproduction. A recent comprehensive gene inventory study concluded that the Amoebozoa are ancestrally sexual. However, the detection of sex genes in some lineages known for their potentially sexual life cycle was very low. Particularly, the genus Cochliopodium, known to undergo a process of cell fusion, karyogamy, and subsequent fission previously described as parasexual, had no meiosis genes detected. This is likely due to low data representation, given the extensive nuclear fusion observed in the genus. In this study, we generate large amounts of transcriptome data for 2 species of Cochliopodium, known for their high frequency of cellular and nuclear fusion, in order to study the genetic basis of the complex life cycle observed in the genus. We inventory 60 sex-related genes, including 11 meiosis-specific genes, and 31 genes involved in fusion and karyogamy. We find a much higher detection of sex-related genes, including 5 meiosis-specific genes not previously detected in Cochliopodium, in this large transcriptome data. The expressed genes form a near-complete recombination machinery, indicating that Cochliopodium is an actively recombining sexual lineage. We also find 9 fusion-related genes in Cochliopodium, although no conserved fusion-specific genes were detected in the transcriptomes. Cochliopodium thus likely uses lineage specific genes for the fusion and depolyploidization processes. Our results demonstrate that Cochliopodium possess the genetic toolkit for recombination, while the mechanism involving fusion and genome reduction remains to be elucidated.

The trans-continental distributions of pentachlorophenol and pentachloroanisole in pine needles indicate separate origins

The production and use of pentachlorophenol (PCP) was recently prohibited/restricted by the Stockholm Convention on persistent organic pollutants (POPs), but environmental data are few and of varying quality. We here present the first extensive dataset of the continent-wide (Eurasia and Canada) occurrence of PCP and its methylation product pentachloroanisole (PCA) in the environment, specifically in pine needles. The highest concentrations of PCP were found close to expected point sources, while PCA chiefly shows a northern and/or coastal distribution not correlating with PCP distribution. Although long-range transport and environmental methylation of PCP or formation from other precursors cannot be excluded, the distribution patterns suggest that such processes may not be the only source of PCA to remote regions and unknown sources should be sought. We suggest that natural sources, e.g., chlorination of organic matter in Boreal forest soils enhanced by chloride deposition from marine sources, should be investigated as a possible partial explanation of the observed distributions. The results show that neither PCA nor total PCP (ΣPCP = PCP + PCA) should be used to approximate the concentrations of PCP; PCP and PCA must be determined and quantified separately to understand their occurrence and fate in the environment. The background work shows that the accumulation of airborne POPs in plants is a complex process. The variations in life cycles and physiological adaptations have to be taken into account when using plants to evaluate the concentrations of POPs in remote areas.

Waning Immunity and Microbial Vaccines-Workshop of the National Institute of Allergy and Infectious Diseases.

Since the middle of the 20th century, vaccines have made a significant public health impact by controlling infectious diseases globally. Although long-term protection has been achieved with some vaccines, immunity wanes over time with others, resulting in outbreaks or epidemics of infectious diseases. Long-term protection against infectious agents that have a complex life cycle and antigenic variation remains a key challenge. Novel strategies to characterize the short- and long-term immune responses to vaccines and to induce immune responses that mimic natural infection have recently emerged. New technologies and approaches in vaccinology, such as adjuvants, delivery systems, and antigen formulations, have the potential to elicit more durable protection and fewer adverse reactions; together with in vitro systems, these technologies have the capacity to model and accelerate vaccine development. The National Institute of Allergy and Infectious Diseases (NIAID) held a workshop on 19 September 2016 that focused on waning immunity to selected vaccines (for Bordetella pertussis, Salmonella enterica serovar Typhi, Neisseria meningitidis, influenza, mumps, and malaria), with an emphasis on identifying knowledge gaps, future research needs, and how this information can inform development of more effective vaccines for infectious diseases.

The serine/threonine phosphatases of apicomplexan parasites.

The balance between phosphorylation and de-phosphorylation, which is delicately regulated by protein kinases and phosphatases, is critical for nearly all biological processes. The Apicomplexa are a large phylum which contains various parasitic protists, including human pathogens, such as Plasmodium, Toxoplasma, Cryptosporidium and Babesia species. The diverse life cycles of these parasites are highly complex and, not surprisingly, many of their key steps are exquisitely regulated by phosphorylation. Interestingly, many of the kinases and phosphatases, as well as the substrates involved in these events are unique to the parasites and therefore phosphorylation constitutes a viable target for antiparasitic intervention. Most progress on this realm has come from studies in Toxoplasma and Plasmodium of their respective kinomes and phosphoproteomes. Nonetheless, given their likely importance, phosphatases have recently become the focus of research within the apicomplexan parasites. In this review, we concentrate on serine/threonine phosphatases in apicomplexan parasites, with the focus on comprehensively identifying and naming protein phosphatases in available apicomplexan genomes, and summarizing the progress of their functional analyses in recent years.

The Life Expectancy of Fallen Angels

In this study, we develop analytic derivations for the projected mean and median times to default for high-yield bonds that have been previously downgraded from investment-grade ratings. These predictive measures are calibrated for both the respective times already spent in the group of high credit grades and the inherent dependency between the observed times in the investment and the speculative classes. We also document an inverse historical relation between the time spent in the group of investment-grade ratings and the noninvestment class. Furthermore, we calculate both the mean and the median times to default for numerous junk bonds in their diverse life cycles. Finally, we ide.tify the most influential accounting and market ratios that can explain the life expectancies of fallen angels. The framework presented hereafter aims to benefit high-yield debt investors.

The long-term persistence of phytoplankton resting stages in aquatic 'seed banks'.

In the past decade, research on long-term persistence of phytoplankton resting stages has intensified. Simultaneously, insight into life-cycle variability in the diverse groups of phytoplankton has also increased. Aquatic 'seed banks' have tremendous significance and show many interesting parallels to terrestrial seed beds of vascular plants, but are much less studied. It is therefore timely to review the phenomenon of long-term persistence of aquatic resting stages in sediment seed banks. Herein we compare function, morphology and physiology of phytoplankton resting stages to factors central for persistence of terrestrial seeds. We review the types of resting stages found in different groups of phytoplankton and focus on the groups for which long-term (multi-decadal) persistence has been shown: dinoflagellates, diatoms, green algae and cyanobacteria. We discuss the metabolism of long-term dormancy in phytoplankton resting stages and the ecological, evolutionary and management implications of this important trait. Phytoplankton resting stages exhibiting long-term viability are characterized by thick, often multi-layered walls and accumulation vesicles containing starch, lipids or other materials such as pigments, cyanophycin or unidentified granular materials. They are reported to play central roles in evolutionary resilience and survival of catastrophic events. Promising areas for future research include the role of hormones in mediating dormancy, elucidating the mechanisms behind metabolic shut-down and testing bet-hedging hypotheses.

Family Planning and Deforestation: Evidence from the Ecuadorian Amazon.

Despite an abundant body of literature exploring the relationship between population growth and forest cover change, comparatively little research has explored the forest cover impacts of family planning use, which is a key determinant of the rate of population growth in many developing country contexts. Using data from a farm-level panel survey in the Northern Ecuadorian Amazon, this paper addresses whether family planning use impacts forest cover change. Longitudinal model results show that after controlling for household life cycle and land use variables, family planning use did not have an independent effect on deforestation, reforestation, or net forest loss between 1990 and 2008. Forest cover change patterns appear indicative of farm life cycle effects. However, family planning use is associated with reduced subsequent fertility among households, suggesting that the relationship between population growth from births and forest cover change may be limited in this setting.

An examination of how source classification impacts credibility and consumer behavior

This research revisits source credibility based upon the popular PESO (Paid, Earned, Shared and Owned) source classification. More specific, this study examines source credibility and channel effectiveness in terms of moving consumers along the communication lifecycle model based upon their exposure to information embedded in paid (traditional advertising and native advertising), earned (traditional news story), shared (independent blogger) and owned (company blog) media. One thousand, five hundred respondents recruited from a consumer panel participated in this 2 (level of involvement) x 5 (source) experimental design study. When respondents were asked to self-report on their levels of trust with various sources, they indicated the highest level of trust with consumer reviews and earned media and the lowest level of trust with native advertising. The experimental design study yielded no major differences among the sources for the communication lifecycle variables. Native advertising was viewed as less credible than traditional advertising in the experimental design. There were no differences in perceived credibility based upon exposure to traditional advertising versus a news story, confirming prior academic research. Suggestions are offered for public relations practitioners on selecting sources for messaging to drive behavior.

Comparative Analysis Highlights Variable Genome Content of Wheat Rusts and Divergence of the Mating Loci.

Three members of the Puccinia genus, Puccinia triticina (Pt), P. striiformis f.sp. tritici (Pst), and P. graminis f.sp. tritici (Pgt), cause the most common and often most significant foliar diseases of wheat. While similar in biology and life cycle, each species is uniquely adapted and specialized. The genomes of Pt and Pst were sequenced and compared to that of Pgt to identify common and distinguishing gene content, to determine gene variation among wheat rust pathogens, other rust fungi, and basidiomycetes, and to identify genes of significance for infection. Pt had the largest genome of the three, estimated at 135 Mb with expansion due to mobile elements and repeats encompassing 50.9% of contig bases; in comparison, repeats occupy 31.5% for Pst and 36.5% for Pgt. We find all three genomes are highly heterozygous, with Pst [5.97 single nucleotide polymorphisms (SNPs)/kb] nearly twice the level detected in Pt (2.57 SNPs/kb) and that previously reported for Pgt. Of 1358 predicted effectors in Pt, 784 were found expressed across diverse life cycle stages including the sexual stage. Comparison to related fungi highlighted the expansion of gene families involved in transcriptional regulation and nucleotide binding, protein modification, and carbohydrate degradation enzymes. Two allelic homeodomain pairs, HD1 and HD2, were identified in each dikaryotic Puccinia species along with three pheromone receptor (STE3) mating-type genes, two of which are likely representing allelic specificities. The HD proteins were active in a heterologous Ustilago maydis mating assay and host-induced gene silencing (HIGS) of the HD and STE3 alleles reduced wheat host infection.

Ecological, Biological, Behavioral and Genetic Adaptation to Xeric Habitats of Triturus Vittatus Vittatus (Urodela) on the Southern Border of its Distribution

In the present mini-review, the results and unpublished data that were collected on Triturus vittatus vittatus in Israel on the southern border of its distribution, and on its adaptation to the Mediterranean semi-arid climate and to arid climate environments on the southern border of its distribution were presented. The contribution of the present paper is in building a model based on the results collected on the distribution, life cycle, behaviour and genetic variations among different populations in northern Israel down to the central coastal plains and near the desert of this species. More specifically, this model is based on the morphology, biology, behaviour and life cycle of T. v. vittatus adaptation. By considering these many parameters, one hypothesis was raised and is supported. The adaptation to and selection of habitats depends mainly on the terrestrial phase and less on the aquatic phases. There are various breeding places in all of the habitats, however, the newts are mainly used to winter ponds, many of which dry up in summer where the larvae can grow and complete metamorphosis. The adaptation of the breeding ponds is not under ecological conditions during larvae growth and complete metamorphosis, but the time of adult breeding and larvae growth occur year-round. The molecular genetic variation in the different areas support our hypothesis that climate is affected by altitude and proximity to the desert. During the life cycle the newts have two habitats aquatic and terrestrial and the adaption to terrestrial habitats is more affected on the newts distribution than the aquatic habitat. The quality model of fitness T. v. vittatus to extreme conditions was suggested.

Institutional Forces and Life Cycle Stages of Women-led SMEs in Developing Economies

Despite women`s enormous involvement in economic activities through Small and Mediumscale Enterprises (SMEs), their progress has been relativelyslow and the macro environmental influences impeding women-led SMEs have been numerous. These impediments vary at different life cycle stages of the women-led business. As informed by life cycle stage theories of organizations, the formation, establishment, continuation and growth stage of businesses each have their own characteristics and needs, and thus entail specific resource requirements to be fulfilled for proceed to the next stage and/or for ensuring survival. This knowledge builds reasonable certainty that the issues undergone by womenled SMEs may vary and be distinctive at diverse life cycle stages of their businesses. The institutional environment of a country can impose restrictions or facilitate growth of entrepreneurship and small businesses. Even though evidence on issues related to formation, establishment, continuity and growth of women-led SMEs are not rare in the existing literature, the impact of the institutional environment at various business life cycle stages have not been well investigated. Thus, the aim of this study is to examine the institutional forces that affect the businesses at diverse life cycle stages of women-led SMEs in developing economies. Drawing from the institutional theory, the present study examines the institutional environmental forces influencing women-led SMEs at different stages of the business life cycles. It develops several propositions, building relationships among three institutional forces and different life cycles stages passed by women-led SMEs. It examines the effects of regulatory, normative and cognitive dimensions of the institutional environment at developing economy contexts. Based on the previous research findings, it encapsulates how apex level environmental conditions of under-developed institutional environments affect the life course of grass-root level women-led SMEs. Concurrently, the findings shed light on which dimension(s) of the institutional environment are most significant at a distinctive stage of women-led SME.

Lifecycle variation, errors-in-variables bias and nonlinearities in intergenerational income transmission: new evidence from Canada

This paper uses Canadian administrative data to test the impact of lifecycle earnings variation and errors-in-variables bias on estimates of intergenerational earnings and income mobility. We find lower levels of mobility compared to previous studies, with a new estimate of the father-son intergenerational earnings elasticity of 0.32. Our analysis also shows that the father-daughter elasticity is much less sensitive to these biases. We investigate whether improved measures of father/child permanent earnings may have a distinct impact on the estimated intergenerational persistence at different parts of the distribution. Taking advantage of exceptionally high sample sizes, we find that the impact of lifecycle bias is more pronounced at the top of the income distribution. We also document that much of the average intergenerational income persistence in Canada can be accounted for by limited mobility at the top, while mobility is significantly higher among children born to low-income fathers. These nonlinear patterns resemble those found in Northern Europe and are different from those observed in the United States.

Extraordinary Adaptive Plasticity of Colorado Potato Beetle: "Ten-Striped Spearman" in the Era of Biotechnological Warfare.

Expanding from remote areas of Mexico to a worldwide scale, the ten-striped insect, the Colorado potato beetle (CPB, Leptinotarsa decemlineata Say), has risen from being an innocuous beetle to a prominent global pest. A diverse life cycle, phenotypic plasticity, adaptation to adverse conditions, and capability to detoxify or tolerate toxins make this insect appear to be virtually “indestructible”. With increasing advances in molecular biology, tools of biotechnological warfare were deployed to combat CPB. In the last three decades, genetically modified potato has created a new challenge for the beetle. After reviewing hundreds of scientific papers dealing with CPB control, it became clear that even biotechnological means of control, if used alone, would not defeat the Colorado potato beetle. This control measure once again appears to be provoking the potato beetle to exhibit its remarkable adaptability. Nonetheless, the potential for adaptation to these techniques has increased our knowledge of this pest and thus opened possibilities for devising more sustainable CPB management programs.

Global Comparisons of Regional Life Cycle Properties and Motion of Multiday Convective Systems: Tropical and Midlatitude Land and Ocean

Abstract Tracking of convective cloud systems (cloud-top temperature <245 K) in geosynchronous satellite images at 3-h intervals is used to determine life cycle statistics of convective systems in four regimes: tropical land and ocean and midlatitude land and ocean, including seasonal comparisons. The ISCCP tracking dataset covers the period 1984–2006. Only systems with lifetimes greater than or equal to 1 day that were moving predominantly eastward or westward are considered, with splits and merges combined into larger extended convective systems. The life cycle variables are lifetime (duration), maximum area, and minimum cloud-top temperature. These are compared to each other and to the speed of longitudinal motion. Distributions and relationships between the life cycle variables are similar to previous studies based on single-day lifetimes, but the current study is globally extensive (all longitudes at lower and middle latitudes) and multidecadal, which allows extension of such results to rarer, larger, and longer-lived convective systems than previous work. Velocity distributions were monomodal with tails skewed in the direction of the zonal mean wind, being almost purely eastward in the midlatitudes but nearly symmetric in both directions with a small westward bias in the tropics. Representative life cycles for each geographical region are formed by averaging together systems with similar lifetimes. These composite life cycles show that, except for the first and last days, the daily evolution of most system variables exhibits little variation during the average multiday convective life cycle, although the cloud area goes through one cycle of expansion and contraction in a lifetime.

The seasonal variation of Tibetan Convective Systems: Satellite observation

AbstractBased on International Satellite Cloud Climatology Project (ISCCP) Convection Tracking Database (CTD) data set, a new definition for the Tibetan Convective System (TCS) is introduced, in which the effects of cirrus and cirrostratus are excluded from the TCS over this region. 2032 TCSs are selected to study their seasonal variations in initiation, frequency, spatial distribution, life cycle, cloud physics, precipitation, and dynamic and thermodynamic characteristics. It is found that the number of TCSs varies seasonally, with the maximum in July and minimum in December. The 10%, 8%, 9%, and 73% TCSs are originated from Tibetan shear, vortex, low, and the rest, respectively. TCSs play an important role in the precipitation of the Tibetan Plateau and its adjacent regions. Even in winter, the rainfall of TCS contributes up to 70% of the total precipitation over the central‐eastern Tibetan Plateau and 30%–70% over Sichuan basin and upper‐middle segment of Yangtze River basin. The seasonal changes of TCSs' cloud properties from ISCCP indicate that the strongest TCSs happen in summer and the weakest in winter, which are consistent with the seasonal variation of TCSs' rainfall observed by TRMM. Besides, TCSs show an asymmetric dynamic and thermodynamic distribution, especially in summer.