ultimate cause
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2021 ◽  
pp. 1-16
Author(s):  
Sean M. Westerveld ◽  
Fang Shi

Ginseng replant disease (GRD) has had a major impact on the American ginseng (Panax quinquefolius L.) industry in Canada and is a threat to its survival. With only 150 yr of domestic ginseng cultivation, GRD and its effect on the industry in North America is well documented compared with replant diseases in other crops. However, minimal research has been published on the etiology and management of GRD. Research and observations of replant diseases of the major commercial Panax species worldwide are presented to propose mechanisms of GRD and potential management options. The available evidence suggests the specific involvement of the soil-borne fungus Ilyonectria mors-panacis (A.A. Hildebr.) A. Cabral & Crous combined with an unknown host-related factor as the ultimate cause of GRD, since other proposed mechanisms seem unlikely to have occurred in the diversity of regions where GRD is reported. Other abiotic and biotic factors influencing the severity of the disease are also likely to be involved. Given the lack of clarity in the scientific literature between problems associated with continuous cultivation of ginseng and true replant disease, a definition of GRD is proposed. The development of an effective and economical management regime will require a better understanding of the mechanisms of GRD. Potential management options include reducing ginseng debris after harvest of the first crop, preplant testing to identify low-risk sites for replanting, fumigation, alternative disinfestation techniques, and fungicides (including biofungicides) targeting I. mors-panacis.


HIMALAYA ◽  
2021 ◽  
Vol 40 (2) ◽  
pp. 32-49
Author(s):  
Geoff Childs ◽  
Sienna R. Craig ◽  
Christina Juenger ◽  
Kristine Hildebrandt

“This Is the End” presents findings from research in which the authors asked survivors of Nepal’s 2015 earthquakes to describe what they know about earthquakes based on their lifelong cultural and environmental experiences, how they responded to the devastating events, and how they view these earthquakes and their aftermath in terms of cause and consequence. The research settings of Tsum, Nubri, Manang, and Mustang were in the midst of rapid socioeconomic transformations and environmental disruptions when the earthquakes struck. Interviews shortly after the event reveal that many people are familiar with scientific concepts like the movement of tectonic plates, yet they attribute the earthquake’s ultimate cause to human activities that disturb autochthonous deities. Their interpretations suggest parallels with signs of impending doom contained within written prophesies, including a decline in religious devotion, the fraying of social cohesion, and environmental disruptions. The linking of written prophesies with lived experiences points toward a Buddhist understanding of conventional and ultimate realities in which people discuss the material and geophysical causes and consequences of earthquakes while also considering moral and cosmological understandings stemming from socially and environmentally destructive behaviors. This article contributes to a growing literature on the intersections of religion and natural disasters.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Chaochao Gao ◽  
Francis Ludlow ◽  
John A. Matthews ◽  
Alexander R. Stine ◽  
Alan Robock ◽  
...  

AbstractState or societal collapses are often described as featuring rapid reductions in socioeconomic complexity, population loss or displacement, and/or political discontinuity, with climate thought to contribute mainly by disrupting a society’s agroecological base. Here we use a state-of-the-art multi-ice-core reconstruction of explosive volcanism, representing the dominant global external driver of severe short-term climatic change, to reveal a systematic association between eruptions and dynastic collapse across two millennia of Chinese history. We next employ a 1,062-year reconstruction of Chinese warfare as a proxy for political and socioeconomic stress to reveal the dynamic role of volcanic climatic shocks in collapse. We find that smaller shocks may act as the ultimate cause of collapse at times of high pre-existing stress, whereas larger shocks may act with greater independence as proximate causes without substantial observed pre-existing stress. We further show that post-collapse warfare tends to diminish rapidly, such that collapse itself may act as an evolved adaptation tied to the influential “mandate of heaven” concept in which successive dynasties could claim legitimacy as divinely sanctioned mandate holders, facilitating a more rapid restoration of social order.


2021 ◽  
Author(s):  
Mangala Tawde ◽  
Abdelaziz Bior ◽  
Michael Feiss ◽  
Paul Freimuth

AbstractAminoglycoside antibiotics interfere with selection of cognate tRNAs during translation, resulting in the production of aberrant proteins that are the ultimate cause of the antibiotic bactericidal effect. To determine if these aberrant proteins are recognized as substrates by the cell’s protein quality control machinery, we studied whether the heat shock (HS) response was activated following exposure of Escherichia coli to the aminoglycoside kanamycin (Kan). Levels of the HS transcription factor σ32 increased about 10-fold after exposure to Kan, indicating that at least some aberrant proteins were recognized as substrates by the molecular chaperone DnaK. To investigate whether toxic aberrant proteins therefore might escape detection by the QC machinery, we studied model aberrant proteins that had a bactericidal effect when expressed in E. coli from cloned genes. As occurred following exposure to Kan, levels of σ32 were permanently elevated following expression of an acutely toxic 48-residue protein (ARF48), indicating that toxic activity and recognition by the QC machinery are not mutually exclusive properties of aberrant proteins, and that the HS response was blocked in these cells at some step downstream of σ32 stabilization. This block could result from halting of protein synthesis or from radial condensation of nucleoids, both of which occurred rapidly following ARF48 induction. Nucleoids were similarly condensed following expression of toxic aberrant secretory proteins, suggesting that transertion of inner membrane proteins, a process that expands nucleoids into an open conformation that promotes growth and gene expression, was disrupted in these cells. The 48-residue ARF48 protein would be well-suited for structural studies to further investigate the toxic mechanism of aberrant proteins.


2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Kelvin Yuan ◽  
Brian Vernachio

The emergence of Covid-19 has deeply disturbed the aviation industry in many aspects. This study examines the effect of Covid-19 on departure delay time and flight cancellation at Philadelphia International Airport (PHL). By analyzing data of nearly 200,000 flights departed from PHL between January 2019 and February 2021, the research found that Covid-19 noticeably reduced flight departure delay time, and flight cancellations sharply rose then quickly dropped. Furthermore, flight departure delay time is highly correlated with the number of flights: the lower the number of flights, the lower the delay time. The ultimate cause is the lack of passengers, as the number of passengers dictates the number of flights an airline can successfully operate. 


2021 ◽  
Vol 8 (8) ◽  
pp. 210804 ◽  
Author(s):  
Asim Renyard ◽  
Regine Gries ◽  
Jan Lee ◽  
Jaime M. Chalissery ◽  
Sebastian Damin ◽  
...  

Ants select sustained carbohydrate resources, such as aphid honeydew, based on many factors including sugar type, volume and concentration. We tested the hypotheses (H1–H3) that western carpenter ants, Camponotus modoc, seek honeydew excretions from Cinara splendens aphids based solely on the presence of sugar constituents (H1), prefer sugar solutions containing aphid-specific sugars (H2) and preferentially seek sugar solutions with higher sugar content (H3). We further tested the hypothesis (H4) that workers of both Ca. modoc and European fire ants, Myrmica rubra , selectively consume particular mono-, di- and trisaccharides. In choice bioassays with entire ant colonies, sugar constituents in honeydew (but not aphid-specific sugar) as well as sugar concentration affected foraging decisions by Ca. modoc . Both Ca. modoc and M. rubra foragers preferred fructose to other monosaccharides (xylose, glucose) and sucrose to other disaccharides (maltose, melibiose, trehalose). Conversely, when offered a choice between the aphid-specific trisaccharides raffinose and melezitose, Ca. modoc and M. rubra favoured raffinose and melezitose, respectively. Testing the favourite mono-, di- and trisaccharide head-to-head, both ant species favoured sucrose. While both sugar type and sugar concentration are the ultimate cause for consumption by foraging ants, strong recruitment of nest-mates to superior sources is probably the major proximate cause.


2021 ◽  
Vol 9 ◽  
Author(s):  
Jiawei Zhang ◽  
Changzhou Deng ◽  
Weipeng Liu ◽  
Zuoqi Tang ◽  
Yue Wang ◽  
...  

The Late Devonian Frasnian–Famennian (F–F) mass extinction has been long-time debated by non-volcanic causes, extra-terrestrial impacts, and large igneous province (LIP) eruptions. To better understand the ultimate cause of the F–F mass extinction, here we investigate the chemostratigraphy of mercury (Hg) and total organic carbon (TOC) on two marine F–F strata in the Dushan area, South China. In both sections, high Hg and Hg/TOC anomalies were observed near the F–F boundary. These anomalies are in line with those recently observed in Morocco, Germany, Poland, and north Russia, suggesting a global Hg flux. The Late Devonian LIP eruptions, which are believed to have emitted massive amounts of Hg, could be responsible for the global Hg and Hg/TOC anomalies around the F–F boundary. The observed Hg and Hg/TOC anomalies coincide with the extinction of Frasnian fauna in the Dushan area, implying a causal link between the Viluy, Kola, and Pripyat-Dnieper-Donets LIP eruptions and the F–F mass extinction.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kateřina Sýkorová ◽  
Jaroslav Flegr

AbstractFactors which indicate lower life expectancy also induce switching to a faster life strategy, that is, a higher investment in current reproduction at the expense of future reproduction and body maintenance. We tested a hypothesis according to which impairment of individual health serves as a signal for switching to a faster life strategy using online-gathered data from 32,911 subjects. Worse health was associated with lower age at menarche and earlier initiation of sexual life in women and higher sexual desire and earlier reproduction in both sexes. Individuals with worse health also exhibited lower sexual activity, lower number of sexual partners, and lower total number of children. These results suggest that impaired health shifts individuals towards a faster life strategy but also has a negative (physiological) effect on behaviours related to sexual life. Signs of a faster life strategy were also found in Rh-negative men in good health, indicating that even just genetic predisposition to worse health could serve as a signal for switching to a faster life strategy. We suggest that improved public health in developed countries and the resulting shift to a slower life strategy could be the ultimate cause of the phenomenon of demographic transition.


Wetlands ◽  
2021 ◽  
Vol 41 (5) ◽  
Author(s):  
Sammy L. King ◽  
Murray K. Laubhan ◽  
Paul Tashjian ◽  
John Vradenburg ◽  
Leigh Fredrickson

AbstractWater is essential for wetland function and sustaining migratory networks for wetland wildlife across broad landscapes. Groundwater declines and surface flow reductions that impact aquatic and wetland organisms are common in the western U.S. and increasingly in the eastern U.S. Agriculture is the largest consumptive water use in the U.S. and understanding economic incentives of water-use practices and the legal context of water rights is foundational to identifying meaningful water solutions that benefit all sectors of society. In this paper, we provide a brief overview of water rights in the U.S. and synthesize the literature to provide a broad overview of how federal farm policy influences water-use decisions. We conclude that the ultimate cause of many water-use conflicts is an inefficient farm economy that is driven by several proximate factors, of which outdated water laws and subsidies that encourage increased water use are among the most important. Development of multi-scale water budgets to assess project impacts and by working more intensively at local watershed and aquifer scales may improve conservation efforts. Finally, detailed analyses to understand the impacts of specific federal policies on agricultural water use may enhance water conservation efforts, facilitate long-term food and water security, and provide greater protection for wetland and aquatic resources.


2021 ◽  
pp. 153537022110092
Author(s):  
Fabrizio Pin ◽  
Lynda F Bonewald ◽  
Andrea Bonetto

Cancer-induced muscle wasting, i.e. cachexia, is associated with different types of cancer such as pancreatic, colorectal, lung, liver, gastric and esophageal. Cachexia affects prognosis and survival in cancer, and it is estimated that it will be the ultimate cause of death for up to 30% of cancer patients. Musculoskeletal alterations are known hallmarks of cancer cachexia, with skeletal muscle atrophy and weakness as the most studied. Recent evidence has shed light on the presence of bone loss in cachectic patients, even in the absence of bone-metastatic disease. In particular, we and others have shown that muscle and bone communicate by exchanging paracrine and endocrine factors, known as myokines and osteokines. This review will focus on describing the role of the most studied myokines, such as myostatin, irisin, the muscle metabolite β-aminoisobutyric acid, BAIBA, and IL-6, and osteokines, including TGF-β, osteocalcin, sclerostin, RANKL, PTHrP, FGF23, and the lipid mediator, PGE2 during cancer-induced cachexia. The interplay of muscle and bone factors, together with tumor-derived soluble factors, characterizes a complex clinical scenario in which musculoskeletal alterations are amongst the most debilitating features. Understanding and targeting the “secretome” of cachectic patients will likely represent a promising strategy to preserve bone and muscle during cancer cachexia thereby enhancing recovery.


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