scholarly journals Somatic evolution and global expansion of an ancient transmissible cancer lineage

Science ◽  
2019 ◽  
Vol 365 (6452) ◽  
pp. eaau9923 ◽  
Author(s):  
Adrian Baez-Ortega ◽  
Kevin Gori ◽  
Andrea Strakova ◽  
Janice L. Allen ◽  
Karen M. Allum ◽  
...  
Keyword(s):  
Cancer Evolution ◽  
Time Resolved ◽  
Somatic Evolution ◽  
Dominant Feature ◽  
Transmissible Cancer ◽  
Clonal Organisms ◽  
Context Specific ◽  
Neutral Genetic Drift ◽  
Mutational Process

The canine transmissible venereal tumor (CTVT) is a cancer lineage that arose several millennia ago and survives by “metastasizing” between hosts through cell transfer. The somatic mutations in this cancer record its phylogeography and evolutionary history. We constructed a time-resolved phylogeny from 546 CTVT exomes and describe the lineage’s worldwide expansion. Examining variation in mutational exposure, we identify a highly context-specific mutational process that operated early in the cancer’s evolution but subsequently vanished, correlate ultraviolet-light mutagenesis with tumor latitude, and describe tumors with heritable hyperactivity of an endogenous mutational process. CTVT displays little evidence of ongoing positive selection, and negative selection is detectable only in essential genes. We illustrate how long-lived clonal organisms capture changing mutagenic environments, and reveal that neutral genetic drift is the dominant feature of long-term cancer evolution.

Prospects of Time-Resolved Photon Emission as a Debug Tool

2002 ◽  
Author(s):  
Jim Vickers ◽  
Nader Pakdaman ◽  
Steven Kasapi
Keyword(s):  
Photon Emission ◽  
Photon Counting ◽  
Signal Propagation ◽  
General Function ◽  
Hot Electron ◽  
Detector Performance ◽  
Time Resolved ◽  
Switching Event ◽  
Emission System

Abstract Dynamic hot-electron emission using time-resolved photon counting can address the long-term failure analysis and debug requirements of the semiconductor industry's advanced devices. This article identifies the detector performance parameters and components that are required to scale and keep pace with the industry's requirements. It addresses the scalability of dynamic emission with the semiconductor advanced device roadmap. It is important to understand the limitations to determining that a switching event has occurred. The article explains the criteria for event detection, which is suitable for tracking signal propagation and looking for logic or other faults in which timing is not critical. It discusses conditions for event timing, whose goal is to determine accurately when a switching event has occurred, usually for speed path analysis. One of the uses of a dynamic emission system is to identify faults by studying the emission as a general function of time.

scholarly journals Six-year source apportionment of submicron organic aerosols from near-continuous measurements at SIRTA (Paris area, France)

2019 ◽  
Author(s):  
Yunjiang Zhang ◽  
Olivier Favez ◽  
Jean-Eudes Petit ◽  
Francesco Canonaco ◽  
Francois Truong ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Biomass Burning ◽  
Ambient Air ◽  
Carbonaceous Aerosols ◽  
Time Resolved ◽  
Pronounced Increase ◽  
Paris Area ◽  
Multi Wavelength ◽  
High Concentrations

Abstract. Organic aerosol (OA) particles are recognized as key factors influencing air quality and climate change. However, highly-time resolved year-round characterizations of their composition and sources in ambient air are still very limited due to challenging continuous observations. Here, we present an analysis of long-term variability of submicron OA using the combination of Aerosol Chemical Speciation Monitor (ACSM) and multi-wavelength aethalometer from November 2011 to March 2018 at a background site of the Paris region (France). Source apportionment of OA was achieved via partially constrained positive matrix factorization (PMF) using the multilinear engine (ME-2). Two primary OA (POA) and two oxygenated OA (OOA) factors were identified and quantified over the entire studied period. POA factors were designated as hydrocarbon-like OA (HOA) and biomass burning OA (BBOA). The latter factor presented a significant seasonality with higher concentrations in winter with significant monthly contributions to OA (18–33 %) due to enhanced residential wood burning emissions. HOA mainly originated from traffic emissions but was also influenced by biomass burning in cold periods. OOA factors were distinguished between their less- and more-oxidized fractions (LO-OOA and MO-OOA, respectively). These factors presented distinct seasonal patterns, associated with different atmospheric formation pathways. A pronounced increase of LO-OOA concentrations and contributions (50–66 %) was observed in summer, which may be mainly explained by secondary OA (SOA) formation processes involving biogenic gaseous precursors. Conversely high concentrations and OA contributions (32–62 %) of MO-OOA during winter and spring seasons were partly associated with anthropogenic emissions and/or long-range transport from northeastern Europe. The contribution of the different OA factors as a function of OA mass loading highlighted the dominant roles of POA during pollution episodes in fall and winter, and of SOA for highest springtime and summertime OA concentrations. Finally, long-term trend analyses indicated a decreasing feature (of about 200 ng m−3 yr−1) for MO-OOA, very limited or insignificant decreasing trends for primary anthropogenic carbonaceous aerosols (BBOA and HOA, along with the fossil fuel and biomass burning black carbon components), and no trend for LO-OOA over the 6+-year investigated period.

scholarly journals Habitat and social context affect memory phenotype, exploration and covariance among these traits

2018 ◽  
Vol 373 (1756) ◽  
pp. 20170291 ◽  
Author(s):  
Sarah Dalesman
Keyword(s):  
Individual Differences ◽  
Cognitive Abilities ◽  
Lymnaea Stagnalis ◽  
Memory Formation ◽  
Long Term Memory ◽  
Wild Populations ◽  
In Captivity ◽  
Specific Trait ◽  
Context Specific

Individual differences in cognitive ability are predicted to covary with other behavioural traits such as exploration and boldness. Selection within different habitats may act to either enhance or break down covariance among traits; alternatively, changing the environmental context in which traits are assessed may result in plasticity that alters trait covariance. Pond snails, Lymnaea stagnalis , from two laboratory strains (more than 20 generations in captivity) and F1 laboratory reared from six wild populations were tested for long-term memory and exploration traits (speed and thigmotaxis) following maintenance in grouped and isolated conditions to determine if isolation: (i) alters memory and exploration; and (ii) alters covariance between memory and exploration. Populations that demonstrated strong memory formation (longer duration) under grouped conditions demonstrated weaker memory formation and reduced both speed and thigmotaxis following isolation. In wild populations, snails showed no relationship between memory and exploration in grouped conditions; however, following isolation, exploration behaviour was negatively correlated with memory, i.e. slow-explorers showing low levels of thigmotaxis formed stronger memories. Laboratory strains demonstrated no covariance among exploration traits and memory independent of context. Together these data demonstrate that the relationship between cognition and exploration traits can depend on both habitat and context-specific trait plasticity. This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.

Context-specific distractors rejection: contextual cues control long-term habituation of attentional capture by abrupt onsets

2019 ◽  
Vol 27 (3-4) ◽  
pp. 291-304 ◽  
Author(s):  
Massimo Turatto ◽  
Francesca Bonetti ◽  
Cinzia Chiandetti ◽  
David Pascucci
Keyword(s):  
Attentional Capture ◽  
Contextual Cues ◽  
Context Specific

Time-resolved photoluminescence from n-doped GaN/Al0.18Ga0.82N short-period superlattices probes carrier kinetics and long-term structural stability

2019 ◽  
Vol 125 (18) ◽  
pp. 185705 ◽  
Author(s):  
Felix Mahler ◽  
Jens W. Tomm ◽  
Klaus Reimann ◽  
Michael Woerner ◽  
Veit Hoffmann ◽  
...  
Keyword(s):  
Structural Stability ◽  
Time Resolved ◽  
Short Period ◽  
Short Period Superlattices ◽  
Time Resolved Photoluminescence

scholarly journals Six-year source apportionment of submicron organic aerosols from near-continuous highly time-resolved measurements at SIRTA (Paris area, France)

2019 ◽  
Vol 19 (23) ◽  
pp. 14755-14776 ◽  
Author(s):  
Yunjiang Zhang ◽  
Olivier Favez ◽  
Jean-Eudes Petit ◽  
Francesco Canonaco ◽  
Francois Truong ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Biomass Burning ◽  
Ambient Air ◽  
Carbonaceous Aerosols ◽  
Time Resolved ◽  
Pronounced Increase ◽  
Paris Area ◽  
Range Transport ◽  
High Concentrations

Abstract. Organic aerosol (OA) particles are recognized as key factors influencing air quality and climate change. However, highly time-resolved long-term characterizations of their composition and sources in ambient air are still very limited due to challenging continuous observations. Here, we present an analysis of long-term variability of submicron OA using the combination of an aerosol chemical speciation monitor (ACSM) and a multiwavelength Aethalometer from November 2011 to March 2018 at a peri-urban background site of the Paris region (France). Source apportionment of OA was achieved via partially constrained positive matrix factorization (PMF) using the multilinear engine (ME-2). Two primary OA (POA) and two oxygenated OA (OOA) factors were identified and quantified over the entire studied period. POA factors were designated as hydrocarbon-like OA (HOA) and biomass burning OA (BBOA). The latter factor presented a significant seasonality with higher concentrations in winter with significant monthly contributions to OA (18 %–33 %) due to enhanced residential wood burning emissions. HOA mainly originated from traffic emissions but was also influenced by biomass burning in cold periods. OOA factors were distinguished between their less- and more-oxidized fractions (LO-OOA and MO-OOA, respectively). These factors presented distinct seasonal patterns, associated with different atmospheric formation pathways. A pronounced increase in LO-OOA concentrations and contributions (50 %–66 %) was observed in summer, which may be mainly explained by secondary OA (SOA) formation processes involving biogenic gaseous precursors. Conversely, high concentrations and OA contributions (32 %–62 %) of MO-OOA during winter and spring seasons were partly associated with anthropogenic emissions and/or long-range transport from northeastern Europe. The contribution of the different OA factors as a function of OA mass loading highlighted the dominant roles of POA during pollution episodes in fall and winter and of SOA for highest springtime and summertime OA concentrations. Finally, long-term trend analyses indicated a decreasing feature (of about −175 ng m−3 yr−1) for MO-OOA, very limited or insignificant decreasing trends for primary anthropogenic carbonaceous aerosols (BBOA and HOA, along with the fossil-fuel and biomass-burning black carbon components) and no statistically significant trend for LO-OOA over the 6-year investigated period.

scholarly journals Origins and Consequences of Chromosomal Instability: From Cellular Adaptation to Genome Chaos-Mediated System Survival

Genes ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1162 ◽  
Author(s):  
Christine J. Ye ◽  
Zachary Sharpe ◽  
Henry H. Heng
Keyword(s):  
Chromosomal Instability ◽  
Molecular Mechanisms ◽  
Evolutionary Model ◽  
Common Mechanism ◽  
Cancer Evolution ◽  
Two Phase ◽  
Cellular Adaptation ◽  
Somatic Evolution ◽  
New Research ◽  
Genome Chaos

When discussing chromosomal instability, most of the literature focuses on the characterization of individual molecular mechanisms. These studies search for genomic and environmental causes and consequences of chromosomal instability in cancer, aiming to identify key triggering factors useful to control chromosomal instability and apply this knowledge in the clinic. Since cancer is a phenomenon of new system emergence from normal tissue driven by somatic evolution, such studies should be done in the context of new genome system emergence during evolution. In this perspective, both the origin and key outcome of chromosomal instability are examined using the genome theory of cancer evolution. Specifically, chromosomal instability was linked to a spectrum of genomic and non-genomic variants, from epigenetic alterations to drastic genome chaos. These highly diverse factors were then unified by the evolutionary mechanism of cancer. Following identification of the hidden link between cellular adaptation (positive and essential) and its trade-off (unavoidable and negative) of chromosomal instability, why chromosomal instability is the main player in the macro-cellular evolution of cancer is briefly discussed. Finally, new research directions are suggested, including searching for a common mechanism of evolutionary phase transition, establishing chromosomal instability as an evolutionary biomarker, validating the new two-phase evolutionary model of cancer, and applying such a model to improve clinical outcomes and to understand the genome-defined mechanism of organismal evolution.

scholarly journals Diurnal aerosol variations do affect daily averaged radiative forcing under heavy aerosol loading observed in Hefei, China

2015 ◽  
Vol 8 (7) ◽  
pp. 2901-2907 ◽  
Author(s):  
Z. Wang ◽  
D. Liu ◽  
Y. Wang ◽  
Z. Wang ◽  
G. Shi
Keyword(s):  
Temporal Resolution ◽  
Radiative Forcing ◽  
Single Scattering ◽  
High Temporal Resolution ◽  
Diurnal Changes ◽  
Data Set ◽  
Time Resolved ◽  
Aerosol Radiative Forcing ◽  
Aerosol Loading

Abstract. A strong diurnal variation of aerosol has been observed in many heavily polluted regions in China. This variation could affect the direct aerosol radiative forcing (DARF) evaluation if the daily averaged value is used as normal rather than the time-resolved values. To quantify the effect of using the daily averaged DARF, 196 days of high temporal resolution ground-based data collected in SKYNET Hefei site during the period from 2007 to 2013 is used to perform an assessment. We demonstrate that strong diurnal changes of heavy aerosol loading have an impact on the 24-h averaged DARF when daily averaged optical properties are used to retrieve this quantity. The DARF errors varying from −7.6 to 15.6 W m−2 absolutely and from 0.1 to 28.5 % relatively were found between the calculations using daily average aerosol properties, and those using time-resolved aerosol observations. These errors increase with increasing daily aerosol optical depth (AOD) and decreasing daily single-scattering albedo (SSA), indicating that the high temporal resolution DARF data set should be used in the model instead of the normal daily-averaged one, especially under heavy aerosol loading conditions for regional campaign studies. We also found that statistical errors (0.3 W m−2 absolutely and 11.8 % relatively) will be less, which means that the effect of using the daily averaged DARF can be weakened by using a long-term observational data set.

Clonal Evolution Models of Tumor Heterogeneity

2015 ◽  
pp. e662-e665 ◽  
Author(s):  
Liran I. Shlush ◽  
Dov Hershkovitz
Keyword(s):  
Environmental Changes ◽  
Clonal Evolution ◽  
Physical Space ◽  
Clonal Expansion ◽  
Relative Fitness ◽  
Cancer Evolution ◽  
Cell Of Origin ◽  
Changing Environment ◽  
Somatic Evolution ◽  
Different Tissues

Somatic/clonal evolution is the process of sequential acquisition of vertically transmittable genetic/epigenetic elements in multicellular organisms. Cancer is the result of somatic evolution. Understanding the processes that shape the evolution of individual tumors might help us to treat cancer more efficiently. The initiating genetic/epigenetic events occur in functional cells and provide the cell of origin a selective advantage under a changing environment. The initiating genetic events tend to be enriched in specific tissues (and are sometimes specific for those tissues), as different tissues undergo different changes in the environment that will activate selective forces on different cells of origin. For the initial clonal expansion to occur premalignant clones need to have a relative fitness advantage over their competitors. It is estimated that the premalignant phase can take several years. Once the premalignant clonal expansion is established, the premalignant cells will contribute to the changing environment and will start competing among themselves. In late stages of cancer evolution the environmental changes might be similar across different tissues, including a lack of physical space, a shortage of energy, and activation of the immune system, and more and more of the hallmarks of cancer will evolve. In this review we will explore the possible clinical relevance of the heterogeneity that evolves during this long somatic evolution. Above all, it should be stressed that the earlier the clonal expansion is recognized, the less diverse and less fit for survival the cells in the population are.

scholarly journals “Computers in the Wild”: Guilds and Next-Generation Unionism in the Information Revolution

2003 ◽  
Vol 48 (S11) ◽  
pp. 181-204 ◽  
Author(s):  
Chris Benner
Keyword(s):  
Spatial Scales ◽  
Information Age ◽  
Central Component ◽  
Information Revolution ◽  
Information Economy ◽  
Personal Support ◽  
Dominant Feature ◽  
In The Wild ◽  
On Line

One of the aspects of the information revolution that has had negative implications for many workers is the erosion of the workplace as a basis for long-term security and collective solidarity. The dramatic pace of technological change, complex restructuring of firms, and continual competitive pressures for rapid innovation that are a central component of the information economy are contributing to fundamental transformations in work and employment. As part of this transformation, the trend towards the centralization of production in large enterprises that was the dominant feature of the industrial era is being superseded by production organized around smaller workplaces connected together in complex, constantly shifting networks operating at multiple spatial scales, from the local to the global. For many workers, one result is greater insecurity, as they increasingly have to update their skills, change jobs and even change careers more frequently. Some analysts have gone so far as to characterize the typical information age worker as a “free-floating individual, connected on-line to a variety of task-performing organizations, ever-competing for resources and personal support, and assuming limited responsibilities towards limited people for a limited time”.

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