614 research outputs found
What's really going on in the South China Sea?
Most analysts and commentators portray China's conduct in the South China Sea as a series of aggressive norm violations by an emerging peer competitor to the United States. We argue that this narrative misreads both the substance and dynamics of recent Chinese policy. Since 2016, China has strenuously sought - and largely managed - not to be in technical violation of the Philippines Arbitration Tribunal ruling despite having publicly disavowed it and has attempted to position itself as a champion of win-win co-operation. This stands in stark contrast to the previous four years in which China rather shockingly began asserting itself with little regard for either legality or diplomatic nicety - the period in which the "aggressive China" narrative gelled. What explains China's whiplash behaviour? Why has the international community largely failed to notice recent changes and adjust the narrative accordingly? We argue that the answers to these questions lie in an eclectic appeal to bureaucratic struggles, the regime's two-level game balancing domestic and international pressures, and psychological considerations. These do not, however, provide satisfactory accounts either of China's behaviour or of the international response in the absence of recognising the crucial importance of second-order rules for making, interpreting, and applying first-order rules in the international system. Social practices of rule-making, in short, provide vital context. Our analysis suggests a series of takeaways both for International Relations theory and for managing relations with China
Music listening as coping behavior : from reactive response to sense-making
Coping is a survival mechanism of living organisms. It is not merely reactive, but also involves making sense of the environment by rendering sensory information into percepts that have meaning in the context of an organism's cognitions. Music listening, on the other hand, is a complex task that embraces sensory, physiological, behavioral, and cognitive levels of processing. Being both a dispositional process that relies on our evolutionary toolkit for coping with the world and a more elaborated skill for sense-making, it goes beyond primitive action-reaction couplings by the introduction of higher-order intermediary variables between sensory input and effector reactions. Consideration of music-listening from the perspective of coping treats music as a sound environment and listening as a process that involves exploration of this environment as well as interactions with the sounds. Several issues are considered in this regard such as the conception of music as a possible stressor, the role of adaptive listening, the relation between coping and reward, the importance of self-regulation strategies in the selection of music, and the instrumental meaning of music in the sense that it can be used to modify the internal and external environment of the listener
Sikap Masyarakat Jakarta Pengguna Aplikasi Grab Terhadap Brand Baru Grab
Grab adalah sebuah brand baru yang merupakan hasil rebranding dari GrabTaxi. Dengan adanya brand baru ini, Grab berharap masyarakat Jakarta dapat mengetahui, menyukai dan kemudian mau menggunakan layanan Grab.Brand baru Grab ini diikuti dengan memperbaharui elemen brand yang terdiri dari brand name, URL, logo, slogan dan packaging. Selama ini, Grab telah mempromosikan informasi brand barunya melalui berbagai media komunikasi. Komponen-komponen yang ada dalam sikap masyarakat Jakarta pengguna aplikasi Grab turut berperan dalam menentukan penilaian terhadap brand baru Grab. Maka, penelitian ini dilakukan untuk mengetahui sikap masyarakat Jakarta pengguna aplikasi Grab terhadap brand baru Grab. Jenis penelitian ini adalah kuantitatif deskriptif dengan menggunakan metode survei untuk mendeskripsikan sikap masyarakat Jakarta pengguna aplikasi Grab terhadap brand baru Grab. Hasil penelitian menunjukkan sikap masyarakat Jakarta pengguna aplikasi Grab positif terhadap brand baru Grab
Genome-wide transcriptomics of aging in the rotifer Brachionus manjavacas, an emerging model system
© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in BMC Genomics 18 (2017): 217, doi:10.1186/s12864-017-3540-x.Understanding gene expression changes over lifespan in diverse animal species will lead to insights to conserved processes in the biology of aging and allow development of interventions to improve health. Rotifers are small aquatic invertebrates that have been used in aging studies for nearly 100 years and are now re-emerging as a modern model system. To provide a baseline to evaluate genetic responses to interventions that change health throughout lifespan and a framework for new hypotheses about the molecular genetic mechanisms of aging, we examined the transcriptome of an asexual female lineage of the rotifer Brachionus manjavacas at five life stages: eggs, neonates, and early-, late-, and post-reproductive adults. There are widespread shifts in gene expression over the lifespan of B. manjavacas; the largest change occurs between neonates and early reproductive adults and is characterized by down-regulation of developmental genes and up-regulation of genes involved in reproduction. The expression profile of post-reproductive adults was distinct from that of other life stages. While few genes were significantly differentially expressed in the late- to post-reproductive transition, gene set enrichment analysis revealed multiple down-regulated pathways in metabolism, maintenance and repair, and proteostasis, united by genes involved in mitochondrial function and oxidative phosphorylation. This study provides the first examination of changes in gene expression over lifespan in rotifers. We detected differential expression of many genes with human orthologs that are absent in Drosophila and C. elegans, highlighting the potential of the rotifer model in aging studies. Our findings suggest that small but coordinated changes in expression of many genes in pathways that integrate diverse functions drive the aging process. The observation of simultaneous declines in expression of genes in multiple pathways may have consequences for health and longevity not detected by single- or multi-gene knockdown in otherwise healthy animals. Investigation of subtle but genome-wide change in these pathways during aging is an important area for future study.Funding for this project was provided by R01 AG037960-01, the American Federation for Aging Research, and the Bay and Paul Foundations
The mate recognition protein gene mediates reproductive isolation and speciation in the Brachionus plicatilis cryptic species complex
© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in BMC Evolutionary Biology 12 (2012): 134, doi:10.1186/1471-2148-12-134.Chemically mediated prezygotic barriers to reproduction likely play an important role in speciation. In facultatively sexual monogonont rotifers from the Brachionus plicatilis cryptic species complex, mate recognition of females by males is mediated by the Mate Recognition Protein (MRP), a globular glycoprotein on the surface of females, encoded by the mmr-b gene family. In this study, we sequenced mmr-b copies from 27 isolates representing 11 phylotypes of the B. plicatilis species complex, examined the mode of evolution and selection of mmr-b, and determined the relationship between mmr-b genetic distance and mate recognition among isolates. Isolates of the B. plicatilis species complex have 1–4 copies of mmr-b, each composed of 2–9 nearly identical tandem repeats. The repeats within a gene copy are generally more similar than are gene copies among phylotypes, suggesting concerted evolution. Compared to housekeeping genes from the same isolates, mmr-b has accumulated only half as many synonymous differences but twice as many non-synonymous differences. Most of the amino acid differences between repeats appear to occur on the outer face of the protein, and these often result in changes in predicted patterns of phosphorylation. However, we found no evidence of positive selection driving these differences. Isolates with the most divergent copies were unable to mate with other isolates and rarely self-crossed. Overall the degree of mate recognition was significantly correlated with the genetic distance of mmr-b. Discrimination of compatible mates in the B. plicatilis species complex is determined by proteins encoded by closely related copies of a single gene, mmr-b. While concerted evolution of the tandem repeats in mmr-b may function to maintain identity, it can also lead to the rapid spread of a mutation through all copies in the genome and thus to reproductive isolation. The mmr-b gene is evolving rapidly, and novel alleles may be maintained and increase in frequency via asexual reproduction. Our analyses indicate that mate recognition, controlled by MMR-B, may drive reproductive isolation and allow saltational sympatric speciation within the B. plicatilis cryptic species complex, and that this process may be largely neutral.This work was
supported by the National Science Foundation grant BE/GenEn MCG-
0412647
Latitudinal and cross-shelf patterns of size, age, growth, and mortality of a tropical damselfish Acanthochromis polyacanthus on the Great Barrier Reef
Patterns of age and growth of a sedentary damsel fish Acanthochromis polyacanthus were tested over a latitudinal range of approximately 10 degrees (1200 km) on the Great Barrier Reef (GBR), Australia. Within latitudes, these patterns were also compared on reefs in distance strata (inner, mid, and outer) across a continental shelf that ranged in width from 52 to 128 km. Although variation in length-max (SLMAX), growth, age-max (AMAX), and the von Bertalanffy metrics of Linf and K were found within and among latitudes, the greatest variation in some demographic characteristics was found among distance strata across the shelf regardless of latitude. Fish were always relatively smaller at inner shelf reefs and grew more slowly when compared to mid and outer shelf reefs; this was true regardless of the color morph of fish. The oldest fish collected was 11 years old, and there was no consistent variation in age-max among distances from shore. On outer reefs, there was a negative linear relationship with age-max and latitude. This "tropical gradient" of age only explained 34% of the variation; furthermore, this was not found when only the oldest group of fish was considered (top 10%). Fish only reached an age-max of six years on the southernmost reefs. There was a trend for a smaller Linf with latitude but it was not significant and Linf did not vary predictably with water temperature. The sampling ofmarine protected areas (MPAs) and fished zones did not confound the resultant patterns in that fish were not consistently larger or older inMPAs or fished zones. Instantaneous mortality rates were 0.245-0.685; they were highest at inner reefs and also showed no consistentMPA-related patterns. Our study suggested that the mid and outer shelf waters of the GBR appeared best suited for growth of A. polyacanthus. In conclusion, the position on continental shelves dominated other geographical patterns and needs to be considered in spatial models of growth. We suggest that local environmental conditions such as turbidity and the quality and quantity of plankton likely have a strong influence on distance across the shelf-based demographic patterns of planktivores
Dynamics of tongue microbial communities with single-nucleotide resolution using oligotyping
.© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 5 (2014): 568, doi:10.3389/fmicb.2014.00568.The human mouth is an excellent system to study the dynamics of microbial communities and their interactions with their host. We employed oligotyping to analyze, with single-nucleotide resolution, oral microbial 16S ribosomal RNA (rRNA) gene sequence data from a time course sampled from the tongue of two individuals, and we interpret our results in the context of oligotypes that we previously identified in the oral data from the Human Microbiome Project. Our previous work established that many of these oligotypes had dramatically different distributions between individuals and across oral habitats, suggesting that they represented functionally different organisms. Here we demonstrate the presence of a consistent tongue microbiome but with rapidly fluctuating proportions of the characteristic taxa. In some cases closely related oligotypes representing strains or variants within a single species displayed fluctuating relative abundances over time, while in other cases an initially dominant oligotype was replaced by another oligotype of the same species. We use this high temporal and taxonomic level of resolution to detect correlated changes in oligotype abundance that could indicate which taxa likely interact synergistically or occupy similar habitats, and which likely interact antagonistically or prefer distinct habitats. For example, we found a strong correlation in abundance over time between two oligotypes from different families of Gamma Proteobacteria, suggesting a close functional or ecological relationship between them. In summary, the tongue is colonized by a microbial community of moderate complexity whose proportional abundance fluctuates widely on time scales of days. The drivers and functional consequences of these community dynamics are not known, but we expect they will prove tractable to future, targeted studies employing taxonomically resolved analysis of high-throughput sequencing data sampled at appropriate temporal intervals and spatial scales.Supported by National Institutes of Health (NIH) National Institute of Dental and Craniofacial Research Grant DE022586 (to Gary G. Borisy). Daniel R. Utter was supported by the Woods Hole Partnership Education Program; A. Murat Eren was supported by a G. Unger Vetlesen Foundation grant to the Marine Biological Laboratory; David B. Mark Welch was supported by NSF DBI-126259
Maternal caloric restriction partially rescues the deleterious effects of advanced maternal age on offspring
© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aging Cell 13 (2014): 623–630, doi:10.1111/acel.12217.While many studies have focused on the detrimental effects of advanced maternal age and harmful prenatal environments on progeny, little is known about the role of beneficial non-Mendelian maternal inheritance on aging. Here, we report the effects of maternal age and maternal caloric restriction (CR) on the life span and health span of offspring for a clonal culture of the monogonont rotifer Brachionus manjavacas. Mothers on regimens of chronic CR (CCR) or intermittent fasting (IF) had increased life span compared with mothers fed ad libitum (AL). With increasing maternal age, life span and fecundity of female offspring of AL-fed mothers decreased significantly and life span of male offspring was unchanged, whereas body size of both male and female offspring increased. Maternal CR partially rescued these effects, increasing the mean life span of AL-fed female offspring but not male offspring and increasing the fecundity of AL-fed female offspring compared with offspring of mothers of the same age. Both maternal CR regimens decreased male offspring body size, but only maternal IF decreased body size of female offspring, whereas maternal CCR caused a slight increase. Understanding the genetic and biochemical basis of these different maternal effects on aging may guide effective interventions to improve health span and life span.This work was supported by the National Institute on Aging Division
of Aging Biology (R01 AG037960-01), the Ellison Medical Foundation/
American Federation for Aging Research Postdoctoral Fellows in Aging Research Program and a Neil Cornell Career Development
Award
Comparative transcriptome analysis of obligately asexual and cyclically sexual rotifers reveals genes with putative functions in sexual reproduction, dormancy, and asexual egg production
© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in BMC Genomics 14 (2013): 412, doi:10.1186/1471-2164-14-412.Sexual reproduction is a widely studied biological process because it is critically important to the genetics, evolution, and ecology of eukaryotes. Despite decades of study on this topic, no comprehensive explanation has been accepted that explains the evolutionary forces underlying its prevalence and persistence in nature. Monogonont rotifers offer a useful system for experimental studies relating to the evolution of sexual reproduction due to their rapid reproductive rate and close relationship to the putatively ancient asexual bdelloid rotifers. However, little is known about the molecular underpinnings of sex in any rotifer species. We generated mRNA-seq libraries for obligate parthenogenetic (OP) and cyclical parthenogenetic (CP) strains of the monogonont rotifer, Brachionus calyciflorus, to identify genes specific to both modes of reproduction. Our differential expression analysis identified receptors with putative roles in signaling pathways responsible for the transition from asexual to sexual reproduction. Differential expression of a specific copy of the duplicated cell cycle regulatory gene CDC20 and specific copies of histone H2A suggest that such duplications may underlie the phenotypic plasticity required for reproductive mode switch in monogononts. We further identified differential expression of genes involved in the formation of resting eggs, a process linked exclusively to sex in this species. Finally, we identified transcripts from the bdelloid rotifer Adineta ricciae that have significant sequence similarity to genes with higher expression in CP strains of B. calyciflorus. Our analysis of global gene expression differences between facultatively sexual and exclusively asexual populations of B. calyciflorus provides insights into the molecular nature of sexual reproduction in rotifers. Furthermore, our results offer insight into the evolution of obligate asexuality in bdelloid rotifers and provide indicators important for the use of monogononts as a model system for investigating the evolution of sexual reproduction.This work was funded by National Institutes of Health
Institute of General Medical Sciences (grant number 5R01GM079484, to JML
and DMW)
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