2,771 research outputs found
Anthropogenic seed dispersal: rethinking the origins of plant domestication
It is well documented that ancient sickle harvesting led to tough rachises, but the other seed dispersal properties in crop progenitors are rarely discussed. The first steps toward domestication are evolutionary responses for the recruitment of humans as dispersers. Seed dispersal–based mutualism evolved from heavy human herbivory or seed predation. Plants that evolved traits to support human-mediated seed dispersal express greater fitness in increasingly anthropogenic ecosystems. The loss of dormancy, reduction in seed coat thickness, increased seed size, pericarp density, and sugar concentration all led to more-focused seed dispersal through seed saving and sowing. Some of the earliest plants to evolve domestication traits had weak seed dispersal processes in the wild, often due to the extinction of animal dispersers or short-distance mechanical dispersal
Niche construction theory in Archaeology: a critical review
Over the past decade, niche construction theory (NCT) has been one of the fastest-growing theories or scholarly approaches in the social sciences, especially within archaeology. It was proposed in the biological sciences 25 years ago and is often referred to as a neglected evolutionary mechanism. Given its rapid acceptance by the archaeological community, it is important that scholars consider how it is being applied and look for discrepancies between applications of the concept. Many critical discussions of NCT have already been published, but most of them are in biology journals and may be overlooked by scholars in the social sciences. In this manuscript, my goal is to synthesis the criticisms of NCT, better allowing archaeologists to independently evaluate its usefulness. I focus on the claims of novelty and differences between NCT and other approaches to conceptualizing anthropogenic ecosystem impacts and culture-evolution feedbacks. I argue that the diverse concepts currently included in the wide-reaching purview of NCT are not new, but the terminology is and may be useful to some scholars. If proponents of the concept are able to unify their ideas, it may serve a descriptive function, but given that lack of a testable explanatory mechanism, it does not have a clear heuristic function.The Origins of NCT - An Earlier Legacy of Thought - Gene–Culture Coevolution - A Lineage of Thought NCT and Ecosystem Engineering An Expanding Concept Dropping the Evolutionary Feedback Applications in the Social Sciences - Origins-of-Agriculture Debates The Three Primary Examples - Lactase Persistence - Sickle Cell Anemia - Hypoxia Adaptations - The Three Key Examples - Are Humans Niche Constructors? Conclusion
Insularity and early domestication: anthropogenic ecosystems as habitat islands
Over the past decade research into early domestication has been transformed by the genomics revolution and increased archaeological investigation. Despite clarification of the timing, locations and genetic processes, most scholars still envision evolutionary responses to human innovations, such as sickle harvesting, tilling, selection for docility or directed breeding. Stepping away from anthropocentric models, evolutionary parallels in the wild can provide case studies for understanding what ecological pressures drove the evolution of the first domestication traits. I contrast evolutionary trends seen among plants and animals confined on oceanic islands with the changes seen in the first cultivated crops and animals. I argue that the earliest villages functioned as habitat islands, applying parallel selective pressures as those on oceanic islands. In this view, the collective assemblage of parallel evolving traits that some scholars refer to as either an island syndrome or domestication syndrome results from similar ecological pressures of insularity, notably ecological release.Islands as ecological models - Habitat islands Parallel evolution in plants - Island speciation - Domestication Parallel evolution in animals - Island speciation - Domestication Rethinking domestication - A unifying mechanism - Ecological release - Archipelagos of the Anthropocen
Diabetes-Induced Expression and Regulation of GLP-1 levels by Bile Acid Receptors (TGR5 & FXR)
Diabetes Mellitus has continued to drastically affect the health of the world and many complications can prove fatal. As long as this metabolic disease persist, research discoveries will need to continue to be made so that patient outcomes and healthcare are dramatically enhanced. In recent years, GLP-1 has been the topic of conversation for diabetes research, due to its promising effects in promoting insulin sensitivity. Furthermore, bile acids and their receptors (TGR5 & FXR) have shown promise in their actions in the regulation of GLP-1, and thus glucose homeostasis. Here we have shown the detection and increased expression of TGR5 and GLP-1, and decreased expression of FXR in diabetic mouse intestinal mucosa tissues. We have also shown the detection and increased expression of these receptors in STC-1 cells. More importantly we have linked the connection of increased glucose concentration (hyperglycemia) to increased TGR5 activation to increased GLP-1 release, thus leading to increased insulin sensitivity and altered diabetic outcomes
Mineralogical Analyses of Basaltic Dune Sands from Ka’u Desert (Hawaii) - Comparison with Martian Dark Dunes
Werden die heutigen Rinderzuchtprogramme den Anforderungen des Ă–kologischen Landbaus gerecht?
Aus der Literaturrecherche und der Umfrage lässt sich folgern, dass noch zu wenig praxisrelevante Methoden entwickelt sind, die eine direkte züchterische Verbesserung der Gesundheit bringen. Es sind aber verschiedene zukunftsträchtige Methoden in Entwicklung, die praxisreif gemacht werden müssen und die auch für die Rinderzucht im ökologischen Landbau wichtig werden könnten
Polymorphic Structure of the Tumor Necrosis Factor (TNF) Locus: An NcoI Polymorphism in the First Intron of the Human TNF-Ăź Gene Correlates with A Variant Amino Acid in Position 26 and a Reduced Level of TNF-Ăź Production
Interpreting diachronic size variation in prehistoric Central Asian cereal grains
The morphology of ancient cereal grains in Central Asia has been heavily discussed as an indicator of specific genetic variants, which are often linked to cultural factors or distinct routes of dispersal. In this paper, we present the largest currently existing database of barley (n = 631) and wheat (n = 349) measurements from Central Asia, obtained from two different periods at the Chap site (ca. 3,500 to 1,000 BC), located in the Tien Shan Mountains of Kyrgyzstan at 2,000 masl. The site is situated at the highest elevation ecocline for successful cereal cultivation and is, therefore, highly susceptible to minor climatic fluctuations that could force gradients up or down in the foothills. We contrast the Chap data with measurements from other second and first millennia BC sites in the region. An evident increase in average size over time is likely due to the evolution of larger grains or the introduction of larger variants from elsewhere. Additionally, site- or region-specific variation is noted, and we discuss potential influences for the formation of genetic varieties, including possible pleiotropic linkages and/or developmental responses to external factors, such as environmental fluctuations, climate, irrigation inputs, soil nutrients, pathologies, and seasonality. External factors acting on developmental or acclamatory responses in plants can be either natural or cultural. We argue that the study of long-term changes in grain morphology on the edges of crop-growing ranges can be informative regarding cultural and environmental constraints in the past.Introduction The chap site Methods Results - Chap Barley Measurements - Chap Wheat Measurements - Early Compact Barley Forms and the Change in Morphotypes Through Time Discussion - Plausible Drivers for Population-Scale Size Changes - Evolution of Ecotypes or Landraces - Pleiotropy - Developmental Plasticity - How to Test Diachronic Seed Changes Conclusio
Pistachio (Pistacia vera) domestication and dispersal out of Central Asia
The pistachio (Pistacia vera L.) is commercially cultivated in semi-arid regions around the globe. Archaeobotanical, genetic, and linguistic data suggest that the pistachio was brought under cultivation somewhere within its wild range, spanning southern Central Asia, northern Iran, and northern Afghanistan. Historically, pistachio cultivation has primarily relied on grafting, suggesting that, as with many Eurasian tree crops, domestication resulted from genetically locking hybrids or favored individuals in place. Plant domestication and dispersal research has largely focused on weedy, highly adaptable, self-compatible annuals; in this discussion, we present a case study that involves a dioecious long-lived perennialmdash;a domestication process that would have required a completely different traditional ecological knowledge system than that utilized for grain cultivation. We argue that the pistachio was brought under cultivation in southern Central Asia, spreading westward by at least 2000 years ago (maybe a few centuries earlier to the mountains of modern Syria) and moved eastward only at the end of the first millennium AD. The seeds remain rare in archaeological sites outside its native range, even into the mid-second millennium AD, and may not have been widely cultivated until the past few hundred years.1. Introduction 1.1. Botany and Ecology 1.2. Progenitor Range and Ecology 2. Domestication 2.1. Grafting and Pollination 2.2. Archaeobotanical and Historical Sources 2.3. Archaeobotany—Central Asian Data 3. Debated Early Evidence 4. Dispersal 5. Linguistics 6. Conclusion
Retreatment with interferon-alpha and ribavirin in primary interferon-alpha non-responders with chronic hepatitis C
Background/Aims: Combination therapy with interferon-alpha (IFN-alpha) plus ribavirin is more efficacious than IFN-alpha monotherapy in previously untreated patients with chronic hepatitis C and patients with IFN-alpha relapse. Only limited data are available in IFN-alpha non-responders. In a multicenter trial we therefore evaluated the efficacy of combination therapy in IFN-alpha-resistant chronic hepatitis C. Methods: Eighty-two patients (mean age 46.8 years, 54 males, 28 females) with chronic hepatitis C were treated with IFN-alpha-2a (3 x 6 MIU/week) and ribavirin (14 mg/kg daily) for 12 weeks. Thereafter, treatment was continued only in virological responders (undetectable serum HCV RNA at week 12) with an IFN-alpha dose of 3 x 3 MIU/week and without ribavirin for a further 9 months. The primary study endpoint was an undetectable HCV RNA by RT-PCR at the end of the 24-week follow-up period. Results: After 12 weeks of combination therapy, an initial virological response was observed in 29 of 82 (35.4%) patients. Due to a high breakthrough rate after IFN-a dose reduction and ribavirin discontinuation, an end-of-treatment response was only achieved in 12 of 82 (14.6%) patients. After the follow-up period, a sustained virological response was observed in 8 of 82 (9.8%) patients. Infection with HCV genotype 3 was the only pretreatment parameter, which could predict a sustained response (HCV-1, 5%; HCV-3, 57.1%; p < 0.001). Conclusions: Despite a high initial response rate of 35.4%, sustained viral clearance was achieved only in 9.8% of the retreated primary IFN-alpha non-responders. Higher IFN-alpha induction and maintenance dose, as well as prolonged ribavirin treatment may possibly increase the virological response rates in non-responders, particularly in those infected by HCV-1
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