Academic literature on the topic 'Ratcheting vs. leveling mechanisms'

This is the graphical abstract of the&nbsp;article published in the <em>International Journal of Modern Anthropology&nbsp;</em>2(14): 177-225. Link to the open access article (activated after publication in November 2020): https://www.ajol.info/index.php/ijma Abstract &mdash; In suggesting that the rules that govern the evolution of cumulative culture&nbsp;are observed in all modern societies, gene-culture coevolution theory implies that the biases that affect the successful &lsquo;ratcheting&rsquo; and efficient transmission of innovations are&nbsp;cross-cultural universals. In the modeling of the theory the stress is placed on demographic strength, the absence of which would render small and isolated populations vulnerable to the &lsquo;treadmill effect&rsquo;, the inevitable consequence of impaired social learning.&nbsp; However, the ethnographic literature documents small groups of isolated hunters and&nbsp;gatherers who have devised intricate risk-reduction networks that do not necessarily proliferate technological innovations and function only in low demographic settings. Moreover, with merit and abilities being equally distributed, the model-based and conformist&nbsp;biases that influence social learning in gene-culture coevolution theory become irrelevant&nbsp;and elaborate &lsquo;leveling mechanisms&rsquo; inhibit the acquisition of status and prestige. As a&nbsp; result, no cultural models can rise to prominence and sway the trajectory of cultural&nbsp;change. Contrary to the predictions of the theory, these societies do not seem to be&nbsp;plagued by cultural loss and, instead of hopelessly running the treadmill and living in&nbsp;poverty, they have developed egalitarian and, to an extent, &lsquo;affluent&rsquo; societies. The model forwarded in this paper resolves this apparent paradox by enrolling the hypothesis of &lsquo;cultural neoteny&rsquo;. It is contended that egalitarian societies &ndash; despite their simple (immediate- return) mode of subsistence &ndash; are not the vestiges of an ancestral/universal stage from&nbsp;which more complex (delayed-return) economies would linearly evolve, but a relatively&nbsp;recent and idiosyncratic achievement through &lsquo;subtractive cultural evolution&rsquo;.

In suggesting that the rules that govern the evolution of cumulative culture are observed in all modern societies, gene-culture coevolution theory implies that the biases that affect the successful ‘ratcheting’ and efficient transmission of innovations are cross-cultural universals. In the modeling of the theory the stress is placed on demographic strength, the absence of which would render small and isolated populations vulnerable to the ‘treadmill effect’, the inevitable consequence of impaired social learning. However, the ethnographic literature documents small groups of isolated hunters and gatherers who have devised intricate risk-reduction networks that do not necessarily proliferate technological innovations and function only in low demographic settings. Moreover, with merit and abilities being equally distributed, the model-based and conformist biases that influence social learning in gene-culture coevolution theory become irrelevant and elaborate ‘leveling mechanisms’ inhibit the acquisition of status and prestige. As a result, no cultural models can rise to prominence and sway the trajectory of cultural change. Contrary to the predictions of the theory, these societies do not seem to be plagued by cultural loss and, instead of hopelessly running the treadmill and living in poverty, they have developed egalitarian and, to an extent, ‘affluent’ societies. The model forwarded in this paper resolves this apparent paradox by enrolling the hypothesis of ‘cultural neoteny’. It is contended that egalitarian societies – despite their simple (immediate-return) mode of subsistence – are not the vestiges of an ancestral/universal stage from which more complex (delayed-return) economies would linearly evolve, but a relatively recent and idiosyncratic achievement through ‘subtractive cultural evolution’.&#x0D; Keywords: anarchic theory in ethnography, cultural heterochrony, cumulative/subtractive cultural evolution, immediate-return/egalitarian societies, ratcheting/leveling mechanisms.

In suggesting that the rules that govern the evolution of cumulative culture are observed in all modern societies, gene-culture coevolution theory implies that the biases that affect the successful &lsquo;ratcheting&rsquo; and efficient transmission of innovations arer cross-cultural universals. In the modeling of the theory the stress is placed on demographic strength, the absence of which would render small and isolated populations vulnerable to the &lsquo;treadmill effect&rsquo;, the inevitable consequence of impaired social learning. Yet, the ethnographic literature documents small groups of isolated hunters and gatherers who have devised intricate risk-reduction networks that do not necessarily proliferate technological innovations and function only in low demographic settings. Moreover, with merit and abilities being equally distributed, the model-based and conformist biases that influence social learning in gene-culture coevolution theory become irrelevant and elaborate &lsquo;leveling mechanisms&rsquo; inhibit the acquisition of status and prestige. As a result, no cultural models can rise to prominence and sway the trajectory of cultural change. Contrary to the predictions of the theory, these societies do not seem to be plagued by cultural loss and, instead of hopelessly running the treadmill and living in poverty, they have developed egalitarian and, to an extent, &lsquo;affluent&rsquo; societies. The model forwarded in this paper resolves this apparent paradox by enrolling the hypothesis of &lsquo;cultural neoteny&rsquo;. It is contended that egalitarian societies &ndash; despite their simple (immediate-return) mode of subsistence &ndash; are not the vestiges of an ancestral/universal stage from which more complex (delayed-return) economies would linearly evolve, but a relatively recent and idiosyncratic achievement through &lsquo;subtractive cultural evolution&rsquo;.

The concept of Open science comes into conflict with the established practice of commercializing the results of research and development work. Commercialization of scientific achievements is both a way to attract funding and a deterrent to intensify the exchange of knowledge and the pace of innovation, especially in basic research. The principles of Open science, providing the ability to widely use and reuse the same data, comparing different approaches and accelerating the development of new research methods, make patenting applied developments much more difficult due to leveling the novelty of inventions in publications and open research data. The purpose of the article is to suggest the possibilities for scientific library to participate in the processes of production, exchange and dissemination of information and knowledge within the framework of the movement of science from the binary system “corporate science vs open science” to hybrid mechanisms of work. Such participation is based on the existing practices of the Centers for Legal and Technical Information and the efforts of scientific library to create an open scientific infrastructure. It involves the expansion of ongoing practices, taking into account the proposed by hybrid science differentiation of Open access to fundamental research and patenting applied developments. Thus, these opportunities are necessary for further modeling the place of scientific library in the ecosystem of open science.

Abstract. The relationship between "clean marine" aerosol optical properties and ocean surface wind speed is explored using remotely sensed data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the CALIPSO satellite and the Advanced Microwave Scanning Radiometer (AMSR-E) on board the AQUA satellite. Detailed data analyses are carried out over 15 regions selected to be representative of different areas of the global ocean for the time period from June 2006 to April 2011. Based on remotely sensed optical properties the CALIPSO algorithm is capable of discriminating "clean marine" aerosols from other types often present over the ocean (such as urban/industrial pollution, desert dust and biomass burning). The global mean optical depth of "clean marine" aerosol at 532 nm (AOD532) is found to be 0.052 ± 0.038 (mean plus or minus standard deviation). The mean layer integrated particulate depolarization ratio of marine aerosols is 0.02 ± 0.016. Integrated attenuated backscatter and color ratio of marine aerosols at 532 nm were found to be 0.003 ± 0.002 sr−1 and 0.530 ± 0.149, respectively. A logistic regression between AOD532 and 10-m surface wind speed (U10) revealed three distinct regimes. For U10 ≤ 4 m s−1 the mean CALIPSO-derived AOD532 is found to be 0.02 ± 0.003 with little dependency on the surface wind speed. For 4 &lt; U10 ≤ 12 m s−1, representing the dominant fraction of all available data, marine aerosol optical depth is linearly correlated with the surface wind speed values, with a slope of 0.006 s m−1. In this intermediate wind speed region, the AOD532 vs. U10 regression slope derived here is comparable to previously reported values. At very high wind speed values (U10 &gt; 18 m s−1), the AOD532-wind speed relationship showed a tendency toward leveling off, asymptotically approaching value of 0.15. The conclusions of this study regarding the aerosol extinction vs. wind speed relationship may have been influenced by the constant lidar ratio used for CALIPSO-derived AOD532. Nevertheless, active satellite sensor used in this study that allows separation of maritime wind induced component of AOD from the total AOD over the ocean could lead to improvements in optical properties of sea spray aerosols and their production mechanisms.

Abstract. With a more-than-doubling in the atmospheric abundance of the potent greenhouse gas methane (CH4) since preindustrial times, and indications of renewed growth following a leveling off in recent years, questions arise as to future trends and resulting climate and public health impacts from continued growth without mitigation. Changes in atmospheric methane lifetime are determined by factors which regulate the abundance of OH, the primary methane removal mechanism, including changes in CH4 itself. We investigate the role of emissions of short-lived species and climate in determining the evolution of tropospheric methane lifetime in a suite of historical (1860–2005) and Representative Concentration Pathway (RCP) simulations (2006–2100), conducted with the Geophysical Fluid Dynamics Laboratory (GFDL) fully coupled chemistry-climate model (CM3). From preindustrial to present, CM3 simulates an overall 5% increase in CH4 lifetime due to a doubling of the methane burden which offsets coincident increases in nitrogen oxide (NOx) emissions. Over the last two decades, however, the methane lifetime declines steadily, coinciding with the most rapid climate warming and observed slow-down in CH4 growth rates, reflecting a possible negative feedback through the CH4 sink. The aerosol indirect effect plays a significant role in the CM3 climate and thus in the future evolution of the methane lifetime, due to the rapid projected decline of aerosols under all four RCPs. In all scenarios, the methane lifetime decreases (by 5–13%) except for the most extreme warming case (RCP8.5), where it increases by 4% due to the near-doubling of the CH4 abundance, reflecting a positive feedback on the climate system. In the RCP4.5 scenario changes in short-lived climate forcing agents reinforce climate warming and enhance OH, leading to a more-than-doubling of the decrease in methane lifetime from 2006 to 2100 relative to a simulation in which only well-mixed greenhouse gases are allowed to change along the RCP4.5 scenario (13% vs. 5%) Future work should include process-based studies to better understand and elucidate the individual mechanisms controlling methane lifetime.

Abstract. Relationship between "clean marine" aerosol optical properties and ocean surface wind speed is explored using remotely sensed data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the CALIPSO satellite and the Advanced Microwave Scanning Radiometer (AMSR-E) on board the AQUA satellite. Detailed data analyses are carried out over 15 regions selected to be representative of different areas of the global ocean for the time period from June 2006 to June 2010. Based on remotely sensed optical properties the CALIPSO algorithm is capable of discriminating "clean marine" aerosols from other types often present over the ocean (such as urban/industrial pollution, desert dust and biomass burning). The global mean optical depth of "clean marine" aerosol at 532 nm (AOD532) is found to be 0.052 ± 0.038. The mean layer integrated volume depolarization ratio of marine aerosols is 0.016 ± 0.012, the value representative of sea salt crystals. Integrated attenuated backscatter and color ratio of marine aerosols at 532 nm were obtained to be 0.003 ± 0.002 sr−1 and 0.530 ± 0.149, respectively. A logistic regression between AOD532 and 10-meter surface wind speed (U10) revealed three distinct regions. For surface winds lower than 4 m s−1, the mean CALIPSO-derived AOD532 is found to be 0.02 ± 0.003 with little dependency on the surface wind speed. For surface winds from 4 m s−1 to 12 m s−1, representing the dominant fraction of all available data, marine aerosol optical depth is linearly correlated with the U10, with a slope of 0.0062 s m−1. In this intermediate wind speed region, the AOD532 vs. U10 regression derived here is comparable to previously reported relationships. At very high wind speed values (U10 &gt; 18 m s−1), the AOD532-wind speed relationship showed a tendency toward leveling off, suggesting the existence of some maximum value for maritime AOD. Results of our calculations suggest that considerable improvements to both optical properties of marine aerosols and their production mechanisms can be achieved by discriminating "clean marine" aerosols (or sea salt particles) from all other types of aerosols present over the ocean.