Population differentiation is a fundamental process of evolution, and many evolutionary studies, such as population genetics, phylogeography and conservation biology, all require the inference of population differenti...Population differentiation is a fundamental process of evolution, and many evolutionary studies, such as population genetics, phylogeography and conservation biology, all require the inference of population differentiation. Recently, there has been a lot of debate over the validity of FST （and its analogue Gsr） as a measure for population genetic differentiation, notably since the proposal of the new index D in 2008. Although several papers reviewed or explored specific features of these statistical measures, a succinct account of this bewildering issue with an overall update appears to be desirable. This is the purpose of the present review. The available statistics generally fall into two categories, represented by Fsv and D, respectively. None of them is perfect in measuring population genetic differentiation. Nevertheless, they each have advantages and are valuable for current re- search. In practice, both indices should be calculated and a comparison of them can generate useful insights into the evolutionary processes that influence population differentiation. FsT （GsT） has some unique irreplaceable characteristics assuring its standing as the default measure for the foreseeable near future. Also, it will continue to serve as the standard for any alternative measures to contrast with. Instead of being anxious about making choice between these indices, one should pay due attention to the equili-brium status and the level of diversity （especially Hs） of the populations, since they largely sway the power of a given statistic to address a specific question. We provide a multi-faceted comparative summary of the various statistics, which can serve as a basic reference for readers to guide their applications [Current Zoology 61 （5）： 886-897, 2015].展开更多
Less attention has been given to soil enzymes that contribute to beneficial rhizosphere interactions in intercropping systems.Therefore,we performed a field experiment by growing faba bean,lupine,and maize in mono and...Less attention has been given to soil enzymes that contribute to beneficial rhizosphere interactions in intercropping systems.Therefore,we performed a field experiment by growing faba bean,lupine,and maize in mono and mixed cultures in a moderately fertile soil.We measured shoot biomass and the kinetic parameters(maximal velocity(V max)and Michaelis-constant(K m))of three key enzymes in the rhizosphere:Leucine-aminopeptidase(LAP),β-1,4-N-acetylglucosaminidase(NAG),and phosphomonoesterase(PHO).Faba bean benefitted in mixed cultures by greater shoot biomass production with both maize and lupine compared to its expected biomass in monoculture.Next,LAP and NAG kinetic parameters were less responsive to mono and mixed cultures across the crop species.In contrast,both the V max and K m values of PHO increased in the faba bean rhizosphere when grown in mixed cultures with maize and lupine.A positive relative interaction index for shoot P and N uptake for faba bean showed its net facilitative interactions in the mixed cultures.Overall,these results suggest that over-productivity in intercropping is crop-specific and the positive intercropping effects could be modulated by P availability.We argue that the enzyme activities involved in nutrient cycling should be incorporated in further research.展开更多
BACKGROUND Despite recent meta-analyses of randomized controlled trials(RCTs),there remains no consensus regarding the preferred surgical treatment for humeral shaft fractures.The fragility index(FI)is an emerging too...BACKGROUND Despite recent meta-analyses of randomized controlled trials(RCTs),there remains no consensus regarding the preferred surgical treatment for humeral shaft fractures.The fragility index(FI)is an emerging tool used to evaluate the robustness of RCTs by quantifying the number of participants in a study group that would need to switch outcomes in order to reverse the study conclusions.AIM To investigate the fragility index of randomized control trials assessing outcomes of operative fixation in proximal humerus fractures.METHODS We completed a systematic review of RCTs evaluating the surgical treatment of humeral shaft fractures.Inclusion criteria included:articles published in English;patients randomized and allotted in 1:1 ratio to 2 parallel arms;and dichotomous outcome variables.The FI was calculated for total complications,each complication individually,and secondary surgeries using the Fisher exact test,as previously published.RESULTS Fifteen RCTs were included in the analysis comparing open reduction plate osteosynthesis with dynamic compression plate or locking compression plate,intramedullary nail,and minimally invasive plate osteosynthesis.The median FI was 0 for all parameters analyzed.Regarding individual outcomes,the FI was 0 for 81/91(89%)of outcomes.The FI exceeded the number lost to follow up in only 2/91(2%)outcomes.CONCLUSION The FI shows that data from RCTs regarding operative treatment of humeral shaft fractures are fragile and does not demonstrate superiority of any particular surgical technique.展开更多
文摘Population differentiation is a fundamental process of evolution, and many evolutionary studies, such as population genetics, phylogeography and conservation biology, all require the inference of population differentiation. Recently, there has been a lot of debate over the validity of FST （and its analogue Gsr） as a measure for population genetic differentiation, notably since the proposal of the new index D in 2008. Although several papers reviewed or explored specific features of these statistical measures, a succinct account of this bewildering issue with an overall update appears to be desirable. This is the purpose of the present review. The available statistics generally fall into two categories, represented by Fsv and D, respectively. None of them is perfect in measuring population genetic differentiation. Nevertheless, they each have advantages and are valuable for current re- search. In practice, both indices should be calculated and a comparison of them can generate useful insights into the evolutionary processes that influence population differentiation. FsT （GsT） has some unique irreplaceable characteristics assuring its standing as the default measure for the foreseeable near future. Also, it will continue to serve as the standard for any alternative measures to contrast with. Instead of being anxious about making choice between these indices, one should pay due attention to the equili-brium status and the level of diversity （especially Hs） of the populations, since they largely sway the power of a given statistic to address a specific question. We provide a multi-faceted comparative summary of the various statistics, which can serve as a basic reference for readers to guide their applications [Current Zoology 61 （5）： 886-897, 2015].
文摘Less attention has been given to soil enzymes that contribute to beneficial rhizosphere interactions in intercropping systems.Therefore,we performed a field experiment by growing faba bean,lupine,and maize in mono and mixed cultures in a moderately fertile soil.We measured shoot biomass and the kinetic parameters(maximal velocity(V max)and Michaelis-constant(K m))of three key enzymes in the rhizosphere:Leucine-aminopeptidase(LAP),β-1,4-N-acetylglucosaminidase(NAG),and phosphomonoesterase(PHO).Faba bean benefitted in mixed cultures by greater shoot biomass production with both maize and lupine compared to its expected biomass in monoculture.Next,LAP and NAG kinetic parameters were less responsive to mono and mixed cultures across the crop species.In contrast,both the V max and K m values of PHO increased in the faba bean rhizosphere when grown in mixed cultures with maize and lupine.A positive relative interaction index for shoot P and N uptake for faba bean showed its net facilitative interactions in the mixed cultures.Overall,these results suggest that over-productivity in intercropping is crop-specific and the positive intercropping effects could be modulated by P availability.We argue that the enzyme activities involved in nutrient cycling should be incorporated in further research.
文摘BACKGROUND Despite recent meta-analyses of randomized controlled trials(RCTs),there remains no consensus regarding the preferred surgical treatment for humeral shaft fractures.The fragility index(FI)is an emerging tool used to evaluate the robustness of RCTs by quantifying the number of participants in a study group that would need to switch outcomes in order to reverse the study conclusions.AIM To investigate the fragility index of randomized control trials assessing outcomes of operative fixation in proximal humerus fractures.METHODS We completed a systematic review of RCTs evaluating the surgical treatment of humeral shaft fractures.Inclusion criteria included:articles published in English;patients randomized and allotted in 1:1 ratio to 2 parallel arms;and dichotomous outcome variables.The FI was calculated for total complications,each complication individually,and secondary surgeries using the Fisher exact test,as previously published.RESULTS Fifteen RCTs were included in the analysis comparing open reduction plate osteosynthesis with dynamic compression plate or locking compression plate,intramedullary nail,and minimally invasive plate osteosynthesis.The median FI was 0 for all parameters analyzed.Regarding individual outcomes,the FI was 0 for 81/91(89%)of outcomes.The FI exceeded the number lost to follow up in only 2/91(2%)outcomes.CONCLUSION The FI shows that data from RCTs regarding operative treatment of humeral shaft fractures are fragile and does not demonstrate superiority of any particular surgical technique.
