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Saflufenacil, atrazine, and pyroxasulfone represent herbicides with a relative field persistence of low, medium, and high, respectively. Field studies were conducted over 2 yr when herbicides and rates were assembled in a factorial arrangement of treatments, and herbicides were applied at rates of 100, 1,000, and 10,000 g ai ha−1. Soil samples were collected over the course of 365 d and analyzed to detect dissipation of the herbicides. Regression analysis was used to quantify the dissipation of each herbicide. The initial herbicide concentration had no effect on the observed dissipation rates of atrazine or saflufenacil; however, pyroxasulfone dissipation was slower at the highest field dosage in both years. Soils from Georgia, Illinois, and Tennessee were fortified with known concentrations of the three herbicides dissolved in water and incubated at 22 C for 154 d. Laboratory studies generally demonstrated slower dissipation compared to field studies, which is plausible because the important loss mechanisms of volatilization or photodegradation do not occur in the laboratory test system. Pyroxasulfone and saflufenacil exhibited no effect of half-life from various initial concentrations, but atrazine exhibited slower degradation occurring at lower initial concentrations. Findings from these studies suggest that initial herbicide concentration has a limited effect on the dissipation of some herbicides: pyroxasulfone in the field and atrazine in the laboratory. This finding is important for researchers who use herbicide degradation rates in simulation modeling because herbicide degradation is often assumed to be independent of the rate applied. Another aspect of this research was the application of each herbicide alone and in combination with the others. Under field and laboratory conditions, there was no change in dissipation if the herbicides were applied alone or in combination.
There are a variety of (“alternative”) axiomatic set theories available to mathematicians. It is worth asking how “alternative” they really are. Might they be no more than rephrasings of the theory (ZFC) that we already have? Here we give an account of the status of the Quine systems in this regard. Some are merely ZF in wolves’ clothing; some are genuine wolves.
The archaeology of the pre-contact Andes provides an ideal study of human responses to climate change given the region's extreme climatic variability, excellent archaeological preservation, and robust paleoclimate records. We evaluate the effects of climate change on the frequency of interpersonal violence in the south-central Andes from ca. 1.5–0.5 ka (AD 470–1540) by comparing incidents of skeletal trauma observed among 2753 crania from 58 sites to rates of ice accumulation at the Quelccaya Glacier. We find that, in the highlands, the odds of identifying inter-personal violence increase on average by a multiplicative factor of 2.4 (1.8–3.2; 95% C.I.) for every 10-centimeter decrease in annual ice accumulation. Our statistical analysis does not detect a relationship between ice accumulation and interpersonal violence rates among coastal or mid-elevation populations. This disparity likely resulted from variable economic and sociopolitical strategies at different elevations. The failure of rain-fed agriculture during periods of drought and concomitant dissolution of organizing polities likely predisposed highland populations to socioeconomic stress and violent competition for limited resources. Conversely, diversity among lowland and midland economies may have buffered against the effect of drought.
The focus of this chapter is on neurobiologically informed and constrained models of working memory as defined by Miller, Galanter, and Pribram (1960): the holding of goals and subgoals in mind in service of planning and executing complex behaviors. In particular, the chapter focuses on models specifically addressing critical challenges and mechanisms following from the need for rapid and selective gating of working memory contents. To start, the important computational challenges posed by the tradeoff between maintaining vs. updating are discussed, providing motivation for the rest of the chapter.After that, several seminal models that have contributed to current thinking are reviewed, including the authors’ own PBWM framework that has proven influential. Finally, several recent developments from the deep learning and neurophysiology literatures are addressed and critical questions and some directions for future progress are discussed.
This chapter aims to outline current knowledge concerning the genetic background of cardiovascular disease (CVD) and its study in ancient human remains. This is demonstrated by the application of a palaeogenetic analysis to the mummy of the Tyrolean Iceman, who presented with both arterial calcifications and a strong genetic predisposition for heart disease. Further discussion highlights how the study of ancient humans can provide new insights into the genetic background of CVD and its intersection with risk factors related to lifestyle.
Following the century-old landmark work by bacteriologist and experimental pathologist Sir Marc Armand Ruffer, who demonstrated the presence of atherosclerosis during autopsies of multiple Egyptian mummies (Ruffer, 1911), an international multidisciplinary group of physicians and scientists (the Horus Team, named for the Egyptian deity; Finch, 2011.) formed to evaluate the existence, extent and aetiology of atherosclerosis in ancient peoples. The Horus Team first described atherosclerotic calcifications on computed tomography (CT) scans in 2009 (Allam et al., 2009).
The Horus and other research teams have found that atherosclerosis is not uncommon in ancient people through the study of their mummified remains (Murphy et al., 2003; Allam et al., 2009, 2011; Thompson et al., 2013, 2014). However, some have postulated that traditional hunter-gatherers are in some ways healthier than modern people and that they had very little atherosclerotic disease (O’Keefe et al., 2010).
The higher-order thalamus (e.g., the pulvinar) is widely thought to play a critical role in its interactions with the neocortex, but identifying precisely what that role is has been somewhat challenging.Here, we describe how a computational approach to understanding the nature of learning and memory in the neocortex suggests three distinct, well-defined contributions of the thalamus: (1) attention, which is perhaps the most widely discussed function of the pulvinar, is supported by a pooled inhibition dynamic involving the thalamic reticular nucleus; (2) predictive learning, where the pulvinar serves as a kind of screen on which predictions are projected, and a temporal difference between predictions and subsequent outcomes can drive error-driven learning throughout the thalamocortical system; and (3) executive function in the circuits involving the frontal cortex, where the mediodorsal (MD) thalamus is largely similar anatomically to the pulvinar and could thus support similar attentional and predictive learning functions, whereas ventral thalamic nuclei receive inhibitory modulation from the basal ganglia, supporting a gating function to regulate action based on a strong competition of Go versus No Go informed by reinforcement learning.Taken together, these important modulatory and learning contributions of the thalamus suggest that a full computational understanding of the neocortex is significantly incomplete without an integration of the thalamic circuitry.
This research examined a potential nuisance aspect of the use of the volatility-reducing agent (VRA) potassium carbonate when combined with glyphosate in spray-tank mixtures. A VRA is now required to be added to dicamba applications to reduce off-target movement from volatility. When no VRA potassium carbonate was added to the spray mixture, there was no pressure buildup. The addition of VRA potassium carbonate plus glyphosate (which lowers the pH) resulted in an observed pressure buildup. Although the gas produced was not identified, it would be expected to be carbon dioxide formed by the dissolution of the carbonate anion from the VRA. Source water pH range from 3.2 to 8.2 had no effect on pressure buildup. Pressure buildup was directly related to water temperature, with a linear response to temperature when the VRA was added last; in contrast, a less direct relationship of temperature to pressure buildup existed at temperatures >30 C when the VRA potassium carbonate was added first. There was no effect on the pressure increase from adding a defoamer or a drift control agent.
This study documents the contexts of platform pipe creation, distribution, and disposition at Illinois Havana Hopewell Tradition (50 BC to AD 200–250) sites to identify regional variation in Hopewell ceremonialism and exchange. We observe that the large deposits of stone pipes buried during communal rituals in the Scioto Valley and the continued influence of the Hopewell Sphere of Interaction have skewed archaeological interpretation. Aside from the several large deposits, pipes are limited in the Scioto Tradition and seldom found in habitation areas. In Illinois, pipe fabrication debris commonly occurs in habitation areas along with numerous examples of pipe repair and maintenance. Local pipestones—often from northern Illinois Sterling deposits—predominate, and exotic imported pipestones are unusual. Pipes are rare inclusions with individual burials as indicators of status, spiritual prowess, achievement, or group membership. The high value placed on pipes as communal sacra in Ohio and their value in Illinois as items of personal influence parallels their common occurrence in Illinois and their unique context in Ohio Hopewell. This study of the contexts of pipe manufacture and deposition reinforces current discussions of such artifact assemblages as important in documenting local variations in political, social, and religious mortuary ceremonialism across the “Hopewellian sphere.”
Fundamental knowledge about the processes that control the functioning of the biophysical workings of ecosystems has expanded exponentially since the late 1960s. Scientists, then, had only primitive knowledge about C, N, P, S, and H2O cycles; plant, animal, and soil microbialinteractions and dynamics; and land, atmosphere, and water interactions. With the advent of systems ecology paradigm (SEP) and the explosion of technologies supporting field and laboratory research, scientists throughout the world were able to assemble the knowledge base known today as ecosystem science. This chapter describes, through the eyes of scientists associated with the Natural Resource Ecology Laboratory (NREL) at Colorado State University (CSU), the evolution of the SEP in discovering how biophysical systems at small scales (ecological sites, landscapes) function as systems. The NREL and CSU are epicenters of the development of ecosystem science. Later, that knowledge, including humans as components of ecosystems, has been applied to small regions, regions, and the globe. Many research results that have formed the foundation for ecosystem science and management of natural resources, terrestrial environments, and its waters are described in this chapter. Throughout are direct and implicit references to the vital collaborations with the global network of ecosystem scientists.
In 2013, India enacted one of the most robust private enforcement regimes for securities fraud violations in the world. Unlike in most other countries, Indian shareholders can now initiate securities fraud lawsuits on their own, represent all other defrauded shareholders unless those shareholders affirmatively opt out, and collect money damages for the entire class. The only thing missing is a better financing mechanism: unlike the United States, Canada, and Australia, India does not permit contingency fees, so class action lawyers cannot front the costs of litigation in exchange for collecting a percentage of what they recover. On the other hand, the 2013 law enacted a public financing regime for securities fraud class actions and it is possible third-party financing will be permitted; these mechanisms may make up some of the loss in effectiveness caused by the lack of contingency fees.