Male allocare among nonhuman primates has frequently been investigated from the perspective of the caretaker. Here we examined whether male allocare relates to environmental factors or the females' energetic stress. ...Male allocare among nonhuman primates has frequently been investigated from the perspective of the caretaker. Here we examined whether male allocare relates to environmental factors or the females' energetic stress. We researched the possible differences of allocare between sexes in free-ranging black-and-white snub-nosed monkeys (Rhinopithecus bieti) in Tibet. A combination of stepwise least squares regression analysis was used to identify the influence of ecological factors (temperature, rainfall, etc.) and infant age that best account for seasonal variation of allocare. The results indicate, except for the functions of infant age, however, that male allocare is a negative function of temperature and female allocare is a positive function of temperature. Specifically, we tested the energetic stress hypothesis, which predicts that the energetic burden of females in a severe environment favour an increased rate of male allocare during the seasons of high energetic stress. We analyzed the allocare difference between high energetic stress season (Mar - Apr), when temperature was low, food availability was scarce, and infants were young, and low energetic stress season (Jun - Aug), based on data obtained during June 2003 - June 2004. Our results supported the energetic stress hypothesis because male allocare in high energetic stress season was higher than that of in low energetic stress season and female allocate was reverse. Therefore, we propose it is the energetic stress on female that make male allocare possible. Male take these interests for other aims and meet some functional hypothesis, which are addressed from the perspective of the male.展开更多
Aiming at gradually developing and perfecting the task-based teaching method, the essay, with enlightment from the Krashen's Input Hypothesis, discusses some issues about input, output, activities and teacher's role...Aiming at gradually developing and perfecting the task-based teaching method, the essay, with enlightment from the Krashen's Input Hypothesis, discusses some issues about input, output, activities and teacher's role in this method.展开更多
Giora proposed that general principle of salience: salient comprehension of figurative and meanings are processed first and literal language be governed by a more meaning salience determines the type of processing in...Giora proposed that general principle of salience: salient comprehension of figurative and meanings are processed first and literal language be governed by a more meaning salience determines the type of processing invoked. According to the Graded Salience Hypothesis, processing familiar metaphors should involve the activation of both their metaphoric and literal meanings, regardless of the type of context in which they are embedded. Processing less familiar metaphors should activate the literal meaning in both types of contexts; however, in the literally biased context, it should be the only one activated. Processing familiar idioms in context biased towards the idiomatic meaning should evoke their figurative meaning almost exclusively, because their figurative meaning is much more salient than their literal meaning. However, processing less familiar idioms in an idiomatic context should activate both their literal and idiomatic meanings because both meanings enjoy similar salience status.展开更多
Inflammatory bowel disease(IBD),including both ulcerative colitis(UC) and Crohn's disease(CD),emerged and dramatically increased for about a century.Despite extensive research,its cause remains regarded as unknown...Inflammatory bowel disease(IBD),including both ulcerative colitis(UC) and Crohn's disease(CD),emerged and dramatically increased for about a century.Despite extensive research,its cause remains regarded as unknown.About a decade ago,a series of findings made me suspect that saccharin may be a key causative factor for IBD,through its inhibition on gut bacteria and the resultant impaired inactivation of digestive proteases and over digestion of the mucus layer and gut barrier(the Bacteria-Protease-Mucus-Barrier hypothesis).It explained many puzzles in IBD such as its emergence and temporal changes in last century.Recently I further found evidence suggesting sucralose may be also linked to IBD through a similar mechanism as saccharin and have contributed to the recent worldwide increase of IBD.This new hypothesis suggests that UC and CD are just two symptoms of the same morbidity,rather than two different diseases.They are both caused by a weakening in gut barrier and only differ in that UC is mainly due to increased infiltration of gut bacteria and the resultant recruitment of neutrophils and formation of crypt abscess,while CD is mainly due to increased infiltration of antigens and particles from gut lumen and the resultant recruitment of macrophages and formation of granulomas.It explained the delayed appearance but accelerated increase of CD over UC and many other phenomena.This paper aims to provide a detailed description of a unified hypothesis regardingthe etiology of IBD,including the cause and mechanism of IBD,as well as the relationship between UC and CD.展开更多
Compared with the measureable but limited K isotope variation in geological samples,biological samples have much larger variations in δ^41 values:from-1.3‰ to+1.1‰ relative to the international K standard NIST SR...Compared with the measureable but limited K isotope variation in geological samples,biological samples have much larger variations in δ^41 values:from-1.3‰ to+1.1‰ relative to the international K standard NIST SRM 3141a.Notably,higher plants generally have δ^41 values that are lower than igneous rocks,whereas sea plants(algae)have δ^41 values that are higher than seawater;the range in δ^41K values of plants encompasses the δ^41 values of both igneous rocks and seawater.Plant cells utilize different K uptake mechanisms in response to highand low-K conditions.In a low-K environment,plant cells use energy-consuming ion pumps for active uptake of K;plant cells in high-K environments use non-energy-consuming ion channels.Based on these facts and on K isotope data from sea and land plants,it is hypothesized that the different K uptake mechanisms are accompanied by distinct K isotope fractionation behaviors or vital effects.The enrichment of light K isotopes in terrestrial plants could be attributed to preferential transport of isotopically light K in the energy-consuming active uptake process by K ion pumps in the membranes of plant root cells.On the other hand,the enrichment of heavy K isotopes in algae may be caused by a combination of the lack of K isotope fractionation during K uptake from seawater via ion channels and the preferential efflux of light K isotopes across the cell membrane back to the seawater.The large variation of K isotope compositions in biological samples therefore may reflect the diversity of isotopic vital effects for K in organisms,which implies the great potential of K isotopes in biogeochemical studies.展开更多
The mineral resources exploitation stage and the economic growth rate are various in different regions of Xinjiang Autonomous region. Using the method of location quotient, this paper identifies and classifies the int...The mineral resources exploitation stage and the economic growth rate are various in different regions of Xinjiang Autonomous region. Using the method of location quotient, this paper identifies and classifies the intensive regions of three types of mineral resources, known as coal, oil and natural gas, respectively. The intensive regions of economic growth were also identified, according to the rate of per capita GDP growth at prefecture, autonomous prefecture and city. The relationships between different mineral resources and economic growth are different, for example, the relationship between economic growth and coal resource is positive, while the relationship between economic growth and oil resource, or natural gas resource is negative. This study empirically examines the effects of natural resources on economic growth of Xinjiang. The results show that whilst natural resources have a positive impact on growth, and can make a negative impact on growth through the transmission channels, such as investment, manufacture, human capital, and scientific and technologic innovation. Moreover, it studies the transmission channels, that is, the effect of natural resources on the other explanatory variables, and calculates the indirect effect of natural resources on growth for each transmission channel, and comprehensive effects of natural resources on growth. The calculated result of comprehensive effects indicates that the positive direct effects of natural resources on growth are shown to outweigh the negative indirect effect of Xinjiang autonomous region.展开更多
The food habits hypothesis (FHH) stands as one of the most striking and often-cited interspecific patterns to emerge from comparative studies of endothermic energetics. The FHH identifies three components of diet th...The food habits hypothesis (FHH) stands as one of the most striking and often-cited interspecific patterns to emerge from comparative studies of endothermic energetics. The FHH identifies three components of diet that potentially produce variability in mass-independent BMR, i.e. food quality, food availability, and food predictability or environmental productivity. The hypothesis predicts that species with diets of low energy content and/or low digestibility should evolve low mass-independent BMRs. The effects of food habits on BMR have been widely investigated at the interspecific level, but the variation between individuals and populations has been largely ignored. Our focus is to compare predictions derived from interspecific studies with data collected from within-species studies to explore the mechanisms and functional significance of adaptive responses predicted by the food-habits hypothesis among birds. We conclude that if BMR is correlated with daily energy expenditure, then organisms that can lower BMR will reduce daily energy expenditure and hence, food requirements. Birds that lower BMR in stressful environments may increase survival. Nevertheless, the mechanism (s) by which birds eating a low quality diet reduce BMR and whether lower BMR affects fitness remain to be determined [Current Zoology 56 (6): 759-766, 2010].展开更多
This paper studies the web third-person effect (WTPE) hypothesis in the context of news websites and social media. Specifically, the study examines the role of social media metrics (i.e., shares and likes of news a...This paper studies the web third-person effect (WTPE) hypothesis in the context of news websites and social media. Specifically, the study examines the role of social media metrics (i.e., shares and likes of news articles) in shaping users' opinion about the websites. Users' news sharing intention in social media is also investigated. Based on a structured online questionnaire (N = 7,404), the results confirm that WTPE can be found in social media metrics without the presence of specific message content. It should be noted that the effect was found at three perceptual levels, self, friends, and other users. Regarding intention for news sharing, text was indicated as the most important reason among Internet users. Finally, the work demonstrates significant correlations between WTPE and article characteristics that influence people's attitudes to share news online.展开更多
We report that Western Sandpipers (Calidris mauri) on Alaska’s Yukon-Kuskokwim River Delta exhibited aggregated breeding behavior at a relatively small spatial scale. Prior to clutch initiation, males performing so...We report that Western Sandpipers (Calidris mauri) on Alaska’s Yukon-Kuskokwim River Delta exhibited aggregated breeding behavior at a relatively small spatial scale. Prior to clutch initiation, males performing song flight displays on a 36 ha plot were aggregated as were subsequent initial nesting attempts on the plot. We tested three hypotheses commonly invoked to explain aggregated breeding in territorial species (social mate choice, predation, and material resources hypotheses), and found support for the material resources hypothesis, as dispersed individuals were more often associated with tundra habitat patches, and aggregated individuals nested more often in undulating-tundra habitat patches compared to patch availability. The pattern of habitat occupancy conformed to an ideal despotic distribution with aggregated nesting birds in undulating-tundra patches experiencing lower reproductive success. On our study plot, older, more aggressive males solicited females more often, and defended larger, more dispersed sites in tundra habitat patches, compared to younger, less aggressive males that were aggregated in undulating-tundra habitat patches. Breeding aggregations are often concentrated on or near a critical resource. In contrast, Western Sandpiper breeding aggregations occur when dominant and/or older individuals exclude younger, subordinate individuals from preferred habitat. Although many taxa of non-colonial birds have been reported to aggregate breeding territories, this is the first quantitative report of aggregated breeding behavior in a non-colonial monogamous shorebird species prior to hatch.展开更多
Cancer metastasis is the most important factor causing patients death. Cancer diseases will be controllable if metastasis does not happen. Concerning the mechanism of cancer metastasis, there are still many points to ...Cancer metastasis is the most important factor causing patients death. Cancer diseases will be controllable if metastasis does not happen. Concerning the mechanism of cancer metastasis, there are still many points to be clarified. Currently, the mechanism of cancer metastasis has been explained from several aspects of its biological behaviors. Here we briefly summarized some newly-developed metastasis models to provide a global glance at this topic.展开更多
Human activity could be changing the Earth's foundations themselves, as we affect multiple systems interacting in feedback mechanisms changing the atmosphere, hydrosphere, cryosphere, biosphere, and even the lithosph...Human activity could be changing the Earth's foundations themselves, as we affect multiple systems interacting in feedback mechanisms changing the atmosphere, hydrosphere, cryosphere, biosphere, and even the lithosphere (solid surface) and asthenosphere (deformable semi-molten rock layer beneath). Anthropogenic movement of ice, water and sediment alters viscosity and movement of the asthenosphere; this induces earthquakes, tsunamis, volcanism and rifting, and may induce plate-tectonic-change. These processes may account for the timing of unexplained contemporary Icelandic, New Zealand, Chilean, Japanese and Indonesian seismicity, volcanism and magma movement. Climate-change and sea-level rise are creating: slip-planes from differential water pore-pressures and/or weakening of previous fault-planes; sediment-change and altered hydrology and reservoir-mass, inducing isostasy and further change in pore-pressure. Loss of plant biomass and diversity alter hydrology, precipitation and transpiration, causing isostasy and further sediment- and climate-change. Increased ocean-mass, temperatures and acidity, reduced oceanic oxygenation, and increased transport of (organic) sediments elevate the production and destabilisation of gas-hydrates, causing slumps and tsunamis. Isostasy and altered viscosity of the asthenosphere increase seismicity, slope and faulting, which are the prime triggers for slumping and tsunamis. Altered asthenosphere flows hasten subduction and rifting landward of subduction, enhancing volcanism. All of these processes predominantly coincide, temporally and spatially, in the coasts and continental margins, and the Pacific ring-of-fire, although response times and extents may vary from immediate to multi-millennial scales and from negligible to catastrophic. Contemporary Icelandic seismic and volcanic activity is explained by depleted magma reserves on the north-western side of the mid-ocean ridge as asthenosphere moves from the constructive boundary under deglaciating and rising Greenland.展开更多
This paper develops a hypothesis of the four factors from the cause of fraudulent financial reporting in terms of thoughts, culture, motive, opportunity and economic trade-off. Then tests whether independent directors...This paper develops a hypothesis of the four factors from the cause of fraudulent financial reporting in terms of thoughts, culture, motive, opportunity and economic trade-off. Then tests whether independent directors monitor and improve the quality of financial report on the basis of 1 170 firms in China by means of OLS regression. The evidence is consistent with the hypothesis.展开更多
The authors investigate the impact of the recent financial crisis on dividend payout policies in the United States. The results are as follows. The authors find that: (l) Firms must have good financial profiles to ...The authors investigate the impact of the recent financial crisis on dividend payout policies in the United States. The results are as follows. The authors find that: (l) Firms must have good financial profiles to support a policy of increasing dividend payouts during a financial crisis; (2) Overall firms increasing dividend payouts are also engaged in stock repurchases; (3) Firms choosing to increase cash dividend payouts seem to have low opportunity costs, that is, they do not have as many exercisable stock options that they may need in the face of possible future redemptions; and (4) During a financial crisis, the aforementioned trade-off between exercisable stock options and increased dividend payouts would peak, as the stock price slides to where it could be expected to V-bound and then became moderate when stock price recovered. The abovementioned findings are consistent with the "silver- lining" hypothesis which the authors proffer to suggest that the storm of economic bad times often creates circumstances that influence dividend payout strategies for firms traded on exchanges in the United States, and different dividend payout strategies may be strategically elected to reveal to the market participants a silver-lining in the cloud of bad times.展开更多
This paper discusses how college English teaching can be carried out based on the output-driven hypothesis. It consists of three sections. Section one briefly describes the views of the output-driven hypothesis with r...This paper discusses how college English teaching can be carried out based on the output-driven hypothesis. It consists of three sections. Section one briefly describes the views of the output-driven hypothesis with relevant theoretical explanations. Section two further illustrates how such teaching practice can be conducted in terms of the teaching objectives, teaching procedures, and methods, and assessment focuses. Section three points out the potential challenges faced by university English teachers when the hypothesis is tested展开更多
This paper is focused on the study of the urban form of Tomar, which was founded in Portugal by the Order of the Temple during the 12th century. It is centered on the site where the Order of the Temple was created, Je...This paper is focused on the study of the urban form of Tomar, which was founded in Portugal by the Order of the Temple during the 12th century. It is centered on the site where the Order of the Temple was created, Jerusalem, and also on the Templar European headquarters, Paris, in Marais neighborhood; as well as on its headquarters in Portugal, Tomar; and finally, on Angra which was set up in Azores at the beginning of the Portuguese discoveries in 1427. While exploring possible Templar principles on setting up medieval geometric cities, the aim of this paper is to expose that Tomar is a truly relevant case on that process and, therefore, that Portugal have had a significant role on medieval geometric urbanism. The achievements of this paper show that the selected territories share common settlement principles which are based on both similar geometric rules and analogous hierarchy schemes. Regarding that, it will be possible to state that cultural and population exchanges with France should not be considered as the sole factor to shape European medieval urbanity. Portugal should have had a role on that process, too. At least, it should be possible to explore other hypothesis on further pieces of research, according to the exposed arguments.展开更多
In October 1996, The Dhaka Stock Exchange (DSE) adopted trading halts for individual stocks, collectively known as "circuit breakers", to reduce the stock market volatility. This paper reviews the existing circuit...In October 1996, The Dhaka Stock Exchange (DSE) adopted trading halts for individual stocks, collectively known as "circuit breakers", to reduce the stock market volatility. This paper reviews the existing circuit breakers literature and developed five hypothesis--"Magnet Effect", "Cool off-Heating (C-H) Effect", "Information Hypothesis", "Volatility Spillover Hypothesis" and "Trading Interferences Hypothesis"--which could be tested empirically not only in the Dhaka Stock Exchange but any stock exchanges around the world. This paper also suggests most appropriate econometric models for empirical testing. GARCH for inter day data and Event Study methodology for intra day data. Moreover, to test the robustness non-parametric tests need to use along with parametric one. Considering the stock market bubbles in 1996, it has been found that it was optimal for the regulators to adopt this trading halt, but not for the market. It failed to protect the market. However, this might be the consequences of misconceptions about the purpose and effectiveness of circuit breakers. Despite many arguments contrary to this mechanism and absence of any conclusive empirical evidence for a fragile stock exchange like DSE, it may be useful sometimes to replace the "invisible hand of the marketplace" with the "visible hand of the market regulators".展开更多
In the past few years, the notion of task complexity has been receiving substantial attention in the field of second language acquisition. This paper explores task complexity from the cognitive perspective by analyzin...In the past few years, the notion of task complexity has been receiving substantial attention in the field of second language acquisition. This paper explores task complexity from the cognitive perspective by analyzing two studies with Skehan's limited capacity hypothesis and Robinson's cognition hypothesis. The two studies, namely You-Jin Kim's (2012) and Mirdamadi and Jong (2015), explore on how linguistic complexity affects language performance. Two hypotheses, Skehan's limited capacity hypothesis and Robinson's cognition hypothesis, explain the two studies from the cognitive perspective by predicting either that increasing task complexity reduces a pool of attentional capacity during task performance or that increasing complex tasks promotes greater accuracy and complexity of speech and writing. It is suggested that language teaching, syllabus designing in particular, should be based on the basis of task complexity.展开更多
基金The Innovation Project of the Chinese Academy of Sciences(grants KSCX2-1-03,KSCX2-1-09)the National Natural Science Foundation of China(30870375)~~
文摘Male allocare among nonhuman primates has frequently been investigated from the perspective of the caretaker. Here we examined whether male allocare relates to environmental factors or the females' energetic stress. We researched the possible differences of allocare between sexes in free-ranging black-and-white snub-nosed monkeys (Rhinopithecus bieti) in Tibet. A combination of stepwise least squares regression analysis was used to identify the influence of ecological factors (temperature, rainfall, etc.) and infant age that best account for seasonal variation of allocare. The results indicate, except for the functions of infant age, however, that male allocare is a negative function of temperature and female allocare is a positive function of temperature. Specifically, we tested the energetic stress hypothesis, which predicts that the energetic burden of females in a severe environment favour an increased rate of male allocare during the seasons of high energetic stress. We analyzed the allocare difference between high energetic stress season (Mar - Apr), when temperature was low, food availability was scarce, and infants were young, and low energetic stress season (Jun - Aug), based on data obtained during June 2003 - June 2004. Our results supported the energetic stress hypothesis because male allocare in high energetic stress season was higher than that of in low energetic stress season and female allocate was reverse. Therefore, we propose it is the energetic stress on female that make male allocare possible. Male take these interests for other aims and meet some functional hypothesis, which are addressed from the perspective of the male.
文摘Aiming at gradually developing and perfecting the task-based teaching method, the essay, with enlightment from the Krashen's Input Hypothesis, discusses some issues about input, output, activities and teacher's role in this method.
文摘Giora proposed that general principle of salience: salient comprehension of figurative and meanings are processed first and literal language be governed by a more meaning salience determines the type of processing invoked. According to the Graded Salience Hypothesis, processing familiar metaphors should involve the activation of both their metaphoric and literal meanings, regardless of the type of context in which they are embedded. Processing less familiar metaphors should activate the literal meaning in both types of contexts; however, in the literally biased context, it should be the only one activated. Processing familiar idioms in context biased towards the idiomatic meaning should evoke their figurative meaning almost exclusively, because their figurative meaning is much more salient than their literal meaning. However, processing less familiar idioms in an idiomatic context should activate both their literal and idiomatic meanings because both meanings enjoy similar salience status.
文摘Inflammatory bowel disease(IBD),including both ulcerative colitis(UC) and Crohn's disease(CD),emerged and dramatically increased for about a century.Despite extensive research,its cause remains regarded as unknown.About a decade ago,a series of findings made me suspect that saccharin may be a key causative factor for IBD,through its inhibition on gut bacteria and the resultant impaired inactivation of digestive proteases and over digestion of the mucus layer and gut barrier(the Bacteria-Protease-Mucus-Barrier hypothesis).It explained many puzzles in IBD such as its emergence and temporal changes in last century.Recently I further found evidence suggesting sucralose may be also linked to IBD through a similar mechanism as saccharin and have contributed to the recent worldwide increase of IBD.This new hypothesis suggests that UC and CD are just two symptoms of the same morbidity,rather than two different diseases.They are both caused by a weakening in gut barrier and only differ in that UC is mainly due to increased infiltration of gut bacteria and the resultant recruitment of neutrophils and formation of crypt abscess,while CD is mainly due to increased infiltration of antigens and particles from gut lumen and the resultant recruitment of macrophages and formation of granulomas.It explained the delayed appearance but accelerated increase of CD over UC and many other phenomena.This paper aims to provide a detailed description of a unified hypothesis regardingthe etiology of IBD,including the cause and mechanism of IBD,as well as the relationship between UC and CD.
基金supported by"1000-talent Program"of China,and National Science Foundation of China(Grant No.41622301)to WL
文摘Compared with the measureable but limited K isotope variation in geological samples,biological samples have much larger variations in δ^41 values:from-1.3‰ to+1.1‰ relative to the international K standard NIST SRM 3141a.Notably,higher plants generally have δ^41 values that are lower than igneous rocks,whereas sea plants(algae)have δ^41 values that are higher than seawater;the range in δ^41K values of plants encompasses the δ^41 values of both igneous rocks and seawater.Plant cells utilize different K uptake mechanisms in response to highand low-K conditions.In a low-K environment,plant cells use energy-consuming ion pumps for active uptake of K;plant cells in high-K environments use non-energy-consuming ion channels.Based on these facts and on K isotope data from sea and land plants,it is hypothesized that the different K uptake mechanisms are accompanied by distinct K isotope fractionation behaviors or vital effects.The enrichment of light K isotopes in terrestrial plants could be attributed to preferential transport of isotopically light K in the energy-consuming active uptake process by K ion pumps in the membranes of plant root cells.On the other hand,the enrichment of heavy K isotopes in algae may be caused by a combination of the lack of K isotope fractionation during K uptake from seawater via ion channels and the preferential efflux of light K isotopes across the cell membrane back to the seawater.The large variation of K isotope compositions in biological samples therefore may reflect the diversity of isotopic vital effects for K in organisms,which implies the great potential of K isotopes in biogeochemical studies.
基金supported by the Natural Science Foundation of China(Grant No.40871253 and 70873119)
文摘The mineral resources exploitation stage and the economic growth rate are various in different regions of Xinjiang Autonomous region. Using the method of location quotient, this paper identifies and classifies the intensive regions of three types of mineral resources, known as coal, oil and natural gas, respectively. The intensive regions of economic growth were also identified, according to the rate of per capita GDP growth at prefecture, autonomous prefecture and city. The relationships between different mineral resources and economic growth are different, for example, the relationship between economic growth and coal resource is positive, while the relationship between economic growth and oil resource, or natural gas resource is negative. This study empirically examines the effects of natural resources on economic growth of Xinjiang. The results show that whilst natural resources have a positive impact on growth, and can make a negative impact on growth through the transmission channels, such as investment, manufacture, human capital, and scientific and technologic innovation. Moreover, it studies the transmission channels, that is, the effect of natural resources on the other explanatory variables, and calculates the indirect effect of natural resources on growth for each transmission channel, and comprehensive effects of natural resources on growth. The calculated result of comprehensive effects indicates that the positive direct effects of natural resources on growth are shown to outweigh the negative indirect effect of Xinjiang autonomous region.
文摘The food habits hypothesis (FHH) stands as one of the most striking and often-cited interspecific patterns to emerge from comparative studies of endothermic energetics. The FHH identifies three components of diet that potentially produce variability in mass-independent BMR, i.e. food quality, food availability, and food predictability or environmental productivity. The hypothesis predicts that species with diets of low energy content and/or low digestibility should evolve low mass-independent BMRs. The effects of food habits on BMR have been widely investigated at the interspecific level, but the variation between individuals and populations has been largely ignored. Our focus is to compare predictions derived from interspecific studies with data collected from within-species studies to explore the mechanisms and functional significance of adaptive responses predicted by the food-habits hypothesis among birds. We conclude that if BMR is correlated with daily energy expenditure, then organisms that can lower BMR will reduce daily energy expenditure and hence, food requirements. Birds that lower BMR in stressful environments may increase survival. Nevertheless, the mechanism (s) by which birds eating a low quality diet reduce BMR and whether lower BMR affects fitness remain to be determined [Current Zoology 56 (6): 759-766, 2010].
文摘This paper studies the web third-person effect (WTPE) hypothesis in the context of news websites and social media. Specifically, the study examines the role of social media metrics (i.e., shares and likes of news articles) in shaping users' opinion about the websites. Users' news sharing intention in social media is also investigated. Based on a structured online questionnaire (N = 7,404), the results confirm that WTPE can be found in social media metrics without the presence of specific message content. It should be noted that the effect was found at three perceptual levels, self, friends, and other users. Regarding intention for news sharing, text was indicated as the most important reason among Internet users. Finally, the work demonstrates significant correlations between WTPE and article characteristics that influence people's attitudes to share news online.
文摘We report that Western Sandpipers (Calidris mauri) on Alaska’s Yukon-Kuskokwim River Delta exhibited aggregated breeding behavior at a relatively small spatial scale. Prior to clutch initiation, males performing song flight displays on a 36 ha plot were aggregated as were subsequent initial nesting attempts on the plot. We tested three hypotheses commonly invoked to explain aggregated breeding in territorial species (social mate choice, predation, and material resources hypotheses), and found support for the material resources hypothesis, as dispersed individuals were more often associated with tundra habitat patches, and aggregated individuals nested more often in undulating-tundra habitat patches compared to patch availability. The pattern of habitat occupancy conformed to an ideal despotic distribution with aggregated nesting birds in undulating-tundra patches experiencing lower reproductive success. On our study plot, older, more aggressive males solicited females more often, and defended larger, more dispersed sites in tundra habitat patches, compared to younger, less aggressive males that were aggregated in undulating-tundra habitat patches. Breeding aggregations are often concentrated on or near a critical resource. In contrast, Western Sandpiper breeding aggregations occur when dominant and/or older individuals exclude younger, subordinate individuals from preferred habitat. Although many taxa of non-colonial birds have been reported to aggregate breeding territories, this is the first quantitative report of aggregated breeding behavior in a non-colonial monogamous shorebird species prior to hatch.
基金Supported by a grant from the National Natural Sciences Foundation of China(No.81071773,30973447,30973471)
文摘Cancer metastasis is the most important factor causing patients death. Cancer diseases will be controllable if metastasis does not happen. Concerning the mechanism of cancer metastasis, there are still many points to be clarified. Currently, the mechanism of cancer metastasis has been explained from several aspects of its biological behaviors. Here we briefly summarized some newly-developed metastasis models to provide a global glance at this topic.
文摘Human activity could be changing the Earth's foundations themselves, as we affect multiple systems interacting in feedback mechanisms changing the atmosphere, hydrosphere, cryosphere, biosphere, and even the lithosphere (solid surface) and asthenosphere (deformable semi-molten rock layer beneath). Anthropogenic movement of ice, water and sediment alters viscosity and movement of the asthenosphere; this induces earthquakes, tsunamis, volcanism and rifting, and may induce plate-tectonic-change. These processes may account for the timing of unexplained contemporary Icelandic, New Zealand, Chilean, Japanese and Indonesian seismicity, volcanism and magma movement. Climate-change and sea-level rise are creating: slip-planes from differential water pore-pressures and/or weakening of previous fault-planes; sediment-change and altered hydrology and reservoir-mass, inducing isostasy and further change in pore-pressure. Loss of plant biomass and diversity alter hydrology, precipitation and transpiration, causing isostasy and further sediment- and climate-change. Increased ocean-mass, temperatures and acidity, reduced oceanic oxygenation, and increased transport of (organic) sediments elevate the production and destabilisation of gas-hydrates, causing slumps and tsunamis. Isostasy and altered viscosity of the asthenosphere increase seismicity, slope and faulting, which are the prime triggers for slumping and tsunamis. Altered asthenosphere flows hasten subduction and rifting landward of subduction, enhancing volcanism. All of these processes predominantly coincide, temporally and spatially, in the coasts and continental margins, and the Pacific ring-of-fire, although response times and extents may vary from immediate to multi-millennial scales and from negligible to catastrophic. Contemporary Icelandic seismic and volcanic activity is explained by depleted magma reserves on the north-western side of the mid-ocean ridge as asthenosphere moves from the constructive boundary under deglaciating and rising Greenland.
文摘This paper develops a hypothesis of the four factors from the cause of fraudulent financial reporting in terms of thoughts, culture, motive, opportunity and economic trade-off. Then tests whether independent directors monitor and improve the quality of financial report on the basis of 1 170 firms in China by means of OLS regression. The evidence is consistent with the hypothesis.
文摘The authors investigate the impact of the recent financial crisis on dividend payout policies in the United States. The results are as follows. The authors find that: (l) Firms must have good financial profiles to support a policy of increasing dividend payouts during a financial crisis; (2) Overall firms increasing dividend payouts are also engaged in stock repurchases; (3) Firms choosing to increase cash dividend payouts seem to have low opportunity costs, that is, they do not have as many exercisable stock options that they may need in the face of possible future redemptions; and (4) During a financial crisis, the aforementioned trade-off between exercisable stock options and increased dividend payouts would peak, as the stock price slides to where it could be expected to V-bound and then became moderate when stock price recovered. The abovementioned findings are consistent with the "silver- lining" hypothesis which the authors proffer to suggest that the storm of economic bad times often creates circumstances that influence dividend payout strategies for firms traded on exchanges in the United States, and different dividend payout strategies may be strategically elected to reveal to the market participants a silver-lining in the cloud of bad times.
文摘This paper discusses how college English teaching can be carried out based on the output-driven hypothesis. It consists of three sections. Section one briefly describes the views of the output-driven hypothesis with relevant theoretical explanations. Section two further illustrates how such teaching practice can be conducted in terms of the teaching objectives, teaching procedures, and methods, and assessment focuses. Section three points out the potential challenges faced by university English teachers when the hypothesis is tested
文摘This paper is focused on the study of the urban form of Tomar, which was founded in Portugal by the Order of the Temple during the 12th century. It is centered on the site where the Order of the Temple was created, Jerusalem, and also on the Templar European headquarters, Paris, in Marais neighborhood; as well as on its headquarters in Portugal, Tomar; and finally, on Angra which was set up in Azores at the beginning of the Portuguese discoveries in 1427. While exploring possible Templar principles on setting up medieval geometric cities, the aim of this paper is to expose that Tomar is a truly relevant case on that process and, therefore, that Portugal have had a significant role on medieval geometric urbanism. The achievements of this paper show that the selected territories share common settlement principles which are based on both similar geometric rules and analogous hierarchy schemes. Regarding that, it will be possible to state that cultural and population exchanges with France should not be considered as the sole factor to shape European medieval urbanity. Portugal should have had a role on that process, too. At least, it should be possible to explore other hypothesis on further pieces of research, according to the exposed arguments.
文摘In October 1996, The Dhaka Stock Exchange (DSE) adopted trading halts for individual stocks, collectively known as "circuit breakers", to reduce the stock market volatility. This paper reviews the existing circuit breakers literature and developed five hypothesis--"Magnet Effect", "Cool off-Heating (C-H) Effect", "Information Hypothesis", "Volatility Spillover Hypothesis" and "Trading Interferences Hypothesis"--which could be tested empirically not only in the Dhaka Stock Exchange but any stock exchanges around the world. This paper also suggests most appropriate econometric models for empirical testing. GARCH for inter day data and Event Study methodology for intra day data. Moreover, to test the robustness non-parametric tests need to use along with parametric one. Considering the stock market bubbles in 1996, it has been found that it was optimal for the regulators to adopt this trading halt, but not for the market. It failed to protect the market. However, this might be the consequences of misconceptions about the purpose and effectiveness of circuit breakers. Despite many arguments contrary to this mechanism and absence of any conclusive empirical evidence for a fragile stock exchange like DSE, it may be useful sometimes to replace the "invisible hand of the marketplace" with the "visible hand of the market regulators".
文摘In the past few years, the notion of task complexity has been receiving substantial attention in the field of second language acquisition. This paper explores task complexity from the cognitive perspective by analyzing two studies with Skehan's limited capacity hypothesis and Robinson's cognition hypothesis. The two studies, namely You-Jin Kim's (2012) and Mirdamadi and Jong (2015), explore on how linguistic complexity affects language performance. Two hypotheses, Skehan's limited capacity hypothesis and Robinson's cognition hypothesis, explain the two studies from the cognitive perspective by predicting either that increasing task complexity reduces a pool of attentional capacity during task performance or that increasing complex tasks promotes greater accuracy and complexity of speech and writing. It is suggested that language teaching, syllabus designing in particular, should be based on the basis of task complexity.