AIM:To investigate usefulness of adherence to gastroesophageal reflux disease(GERD) guideline established by the Spanish Association of Gastroenterology.METHODS:Prospective,observational and multicentre study of 301 p...AIM:To investigate usefulness of adherence to gastroesophageal reflux disease(GERD) guideline established by the Spanish Association of Gastroenterology.METHODS:Prospective,observational and multicentre study of 301 patients with typical symptoms of GERD who should be managed in accordance with guidelines and were attended by gastroenterologists in daily practice.Patients(aged > 18 years) were eligible for inclusion if they had typical symptoms of GERD(heartburn and/or acid regurgitation) as the major complaint in the presence or absence of accompanying atypical symptoms,such as dyspeptic symptoms and/or supraesophageal symptoms.Diagnostic and therapeutic decisions should be made based on specific recommendations of the Spanish clinical practice guideline for GERD which is a widely disseminated and well known instrument among Spanish in digestive disease specialists.RESULTS:Endoscopy was indicated in 123(41%) patients:50 with alarm symptoms,32 with age > 50 years without alarm symptom.Seventy-two patients(58.5%) had esophagitis(grade A,23,grade B,28,grade C,18,grade D,3).In the presence of alarm symptoms,endoscopy was indicated consistently with recommendations in 98% of cases.However,in the absence of alarm symptoms,endoscopy was indicated in 33% of patients > 50 years(not recommended by the guideline).Adherence for proton pump inhibitors(PPIs) therapy was 80%,but doses prescribed were lower(half) in 5% of cases and higher(double) in 15%.Adherence regarding duration of PPI therapy was 69%;duration was shorter than recommended in 1%(4 wk in esophagitis grades C-D) or longer in 30%(8 wk in esophagitis grades A-B or in patients without endoscopy).Treatment response was higher when PPI doses were consistent with guidelines,although differences were not significant(95% vs 85%).CONCLUSION:GERD guideline compliance was quite good although endoscopy was over indicated in patients > 50 years without alarm symptoms;PPIs were prescribed at higher doses and longer duration.展开更多
Tethered cord syndrome is a progressive disease with a typically insidious onset in infants and children, and which can lead to persistent progress of neurological deficits and a high rate of disability without timely...Tethered cord syndrome is a progressive disease with a typically insidious onset in infants and children, and which can lead to persistent progress of neurological deficits and a high rate of disability without timely intervention. The purpose of this study was to investigate the curative effect of microsurgery in children with different types of tethered cord syndrome. In this study, we analyzed 326 patients with tethered cord syndrome, aged from 2 months to 14 years old, who were followed for 3-36 months after microscopic surgery. Based on clinical manifestations and imaging findings, these patients were classified into five types: tight ilium terminale (53 cases), lipomyelome- ningocele (55 cases), lipomatous malformation (124 cases), postoperative adhesions (56 cases), and split cord malformation (38 cases). All patients underwent microsurgery. Curative effects were measured before and 3 months after surgery by Spina Bifida Neurological Scale based on sensory and motor functions, reflexes, and bladder and bowel function. The results showed that Spina Bifida Neurological Scale scores improved in all five types after surgery. Overall effective rates in these patients were 75%. Effective rates were 91% in tight ilium terminale, 84% in lipomyelomeningocele, 65% in lipomatous malformation, 75% in postoperative adhesion, and 79% in split cord mal- formation. Binary logistic regression analysis revealed that types of tethered cord syndrome (lipoma-type or not) and symptom duration before surgery were independent influencing factors of surgical outcome. These results show that therapeutic effect is markedly different in patients with different types of tethered cord syndrome. Suitable clinical classification for tethered cord syndrome will be helpful in predicting prognosis and guiding treatment. This trial has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800016464).展开更多
Objective To investigate the clinical applications of coronary CT angiography in patients with suspected coronary artery disease and identify factors that affect CT findings. Methods Medical records of patients suspec...Objective To investigate the clinical applications of coronary CT angiography in patients with suspected coronary artery disease and identify factors that affect CT findings. Methods Medical records of patients suspected of coronary artery disease over a period of 12 months from a tertiary teaching hospital were retrospectively reviewed. Patient age, sex (male/female), duration of symptoms and abnormal rates of coronary CT angiography scans were analysed to investigate the relationship among these parameters. The patients by age were characterized into five groups: under 36 years, 36-45 years, 46-55 years, 56455 years and more than 66 years, respectively; while the duration of symptoms was also classified into five groups: less than one week, one week to one month, one to three months, three to six months and more than six months. Results Of the 880 patient records reviewed, 800 met the above study criteria. Five hundred and forty nine patients demonstrated abnormal CT findings (68.6%). There was no significant difference in the percentage of abnormal CT findings based on patient sex and the duration of symptoms (P = 0.14). The abnormal rates of coronary CT angiography, however, increased significantly with increasing age (P 〈 0.001); with patients over 65 years of age 2.5 times more likely to have an abnormal CT scan relative to a patient under 45 years. A significant difference was found between abnormal coronary CT angiography and the duration of symptoms (P = 0.012). Conclusions Our results indicate coronary CT angiography findings are significantly related to the patient age group and duration of symptoms. Clinical referral for coronary CT angiography of patients with suspected coronary artery disease needs to be justified with regard to the judicious use of this imaging modality.展开更多
Mountainous areas have been long recognized as particularly important for the planet and sustainable mountain development is a global priority. In order to improve the socioeconomic development perspectives of mountai...Mountainous areas have been long recognized as particularly important for the planet and sustainable mountain development is a global priority. In order to improve the socioeconomic development perspectives of mountain societies, efficient and well-targeted energy strategies should be formed. An important step towards this direction is adequate understanding of local conditions and specific features that affect energy sector. This procedure allows the inclusion of "locality" in energy planning and so, decentralized energy production is facilitated. The present study attempts to determine the particular energy identity of mountainous areas. Greece, which is the second most mountainous country in the EU, has been selected as a case study. Essential features of the mountainous space have been selected, namely altitude, inclination, remoteness, lack of productive activities, old buildings/vernacular architecture, in order to explore their interrelation with the energy sector. Based on literature review and research findings the interaction between mountainous character and energy is outlined. Therefore, a framework of the characteristics of mountain energy identity is composed, which can provide support to the formation of specialized energy policy for mountainous areas. Some of the main findings of the present study include the significantly increased energy loads of mountainous areas, the abundance of renewable energy potential in high – altitude areas, the vulnerability of mountain societies to energy poverty and the difficulties in sitting energy projects in the restricted usable space of mountains. Since the literature regarding mountains and energy is rather poor the present paper aspires to be a step towards highlighting the importance of energy issues for mountain areas and societies. By determining the features of mountain energy identity energy planning in high – altitude areas and so, helping make energy planning more effective, such research works can be parts of sustainable development strategies for mountainous areas.展开更多
Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually ...Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually have unique shape. Its geometrical shape assumed as tapered hollow pipe. This study aims to find the effect of bamboo taper to its strength properties on center point bending test. The ratio between the Modulus of Rupture (S~) calculated in the center point, and the maximum bending stress along the beam is called strength ratio of taper (Ct). The theoretical calculation results Ct value is 1 if the taper lower than 0.023, while Ct value become lower if the taper is higher than 0.023. The survey on Ampel (Bambusa vulgaris Schrad.), Tali (Gigantochloa apus (BI. Ex Schult. f) Kurz), Gombong (Gigantochloa verticillata (Willd.) Munro), and Mayan (Gigantochloa robusta Kurz.) found that the overall taper range is -0.0047-0.0088 and 0-0.0127 for inner and outer taper respectively. On that overall range the Ct value is always 1, so it is reasonable to ignore the taper effect on one point bending test.展开更多
Objective The most important complication after low anterior resection(LAR) for mid-low rectal cancer is symptomatic anastomotic leakage(AL). More than one-third of patients with rectal cancer who underwent LAR will h...Objective The most important complication after low anterior resection(LAR) for mid-low rectal cancer is symptomatic anastomotic leakage(AL). More than one-third of patients with rectal cancer who underwent LAR will have functional stomas during primary operation. The aim of this retrospective study was to evaluate the risk factors associated with clinical AL following LAR without diversional stomas.Methods Between 2012 and 2017, information about 578 consecutive patients with rectal tumors less than 12 cm from the anal verge who underwent LAR without diversional stomas by the same surgical team was collected retrospectively. A standardized extraperitonealized anastomosis and pelvic drainage were conducted for all patients during primary operations, and the outcome of interest was clinical AL. The associations between AL and 14 patient-related and surgical variables were examined by both univariate chi-square test and multivariate logistic regression analysis.Results The AL rate was 7.27%(42 of 578). Univariate and multivariate analyses showed that male sex(P = 0.018), mid-low rectal cancer(located 10 cm or less above the anal verge)(P = 0.041), presence of diabetes(odds ratio = 2.117), longer duration of operation(odds ratio = 1.890), and intraoperative contamination(odds ratio = 2.163) were risk factors of AL for LAR without diversional stoma and independently predictive of clinical AL. Nearly 83.3%(35 of 42) of leakage could be cured by persistent pelvic irrigation-suction-drainage without surgical intervention. Only 7 patients(16.7%) with severe complications, such as peritonitis, and fistula, required reoperation, and functional stoma was used as a salvage treatment.Conclusion From the findings of this retrospective survey, we identified that mid-low rectal cancer and male sex were independent risk factors for developing clinical AL after LAR without diversional stomas, as well as longer duration of operation, presence of diabetes, and contamination of the operative field. Moreover, we deemed that LAR without diversional stomas for mid-low rectal cancers was safe, effective, and feasible. Extraperitonealized anastomosis and pelvic drainage obtained a relatively low rate of AL and avoided unnecessary functional stomas. Pelvic irrigation-suction-drainage was an effective procedure to resolve AL, and functional stoma was potentially used as a salvage modality for serious leakage.展开更多
OBJECTIVE: To investigate the antidepressant-likeeffect of active fraction of Polyrhachis vicina Roger(AFPR) in a rat depression model, and to elucidate the underlying mechanism.METHODS: AFPR was extracted with ethano...OBJECTIVE: To investigate the antidepressant-likeeffect of active fraction of Polyrhachis vicina Roger(AFPR) in a rat depression model, and to elucidate the underlying mechanism.METHODS: AFPR was extracted with ethanol followed by petroleum ether. Its antidepressant-like effect was investigated in mice by tail suspension test(TST), forced swimming test(FST) and open field test(OPT). A repeated dose of reserpine(0.5 mg/kg, daily for 14 d) was used to establish a rat depression model. Fluoxetine was used as positive control agent. The effect of AFPR on reserpine-induced ptosis, hypothermia and akinesia, the levels of monoamines and their metabolites, and the activity of monoamine oxidase(MAO) in hippocampus and prefrontal cortex were determined.RESULTS: Administration of AFPR by gavage at 160 and 320 mg/kg significantly reduced the duration of immobility in the FST and TST, and did not affect locomotor activity in the OPT. In the reserpine-induced depression model, AFPR attenuated anhedonia, demonstrated by reversing hypothermia, akinesia and sucrose consumption. AFPR significantly increased the concentration of monoamines, including dopamine, serotonin, noradrenaline and acetylcholine.CONCLUSION: AFPR normalized the metabolism rates of noradrenaline, serotonin and dopamine,and the activity of MAO, which were altered by chronic reserpine exposure. The findings suggest that modulation of the monoaminergic neurotransmitter system likely underlies the antidepressant-like effect of AFPR.展开更多
Male-male competition and female mate choice may both play important roles in driving and maintaining reproductive isolation between species. When previously allopatric species come into secondary contact with each ot...Male-male competition and female mate choice may both play important roles in driving and maintaining reproductive isolation between species. When previously allopatric species come into secondary contact with each other due to introductions, they provide an opportunity to evaluate the identity and strength of reproductive isolating mechanisms. If reproductive isolation is not maintained, hybridization may occur. We examined how reproductive isolating mechanisms medi- ate hybridization between endemic populations of the Red River pupfish Cyprinodon rubrofluviati- lis and the recently introduced sheepshead minnow C. variegatus. In lab-based dominance trials, males of both species won the same number of competitions. However, male C. rubrofluviatilis that won competitions were more aggressive than C, variegatus winners, and more aggression was needed to win against competitor C. variagatus than allopatric C. rubrofluviatilis. Duration of fights also differed based on the relatedness of the competitor. In dichotomous mate choice trials, there were no conspecific or heterospecific preferences expressed by females of either species. Our findings that male-male aggression differs between closely and distantly related groups, but female choice does not suggest that male-male competition may be the more likely mechanism to impede gene flow in this system.展开更多
文摘AIM:To investigate usefulness of adherence to gastroesophageal reflux disease(GERD) guideline established by the Spanish Association of Gastroenterology.METHODS:Prospective,observational and multicentre study of 301 patients with typical symptoms of GERD who should be managed in accordance with guidelines and were attended by gastroenterologists in daily practice.Patients(aged > 18 years) were eligible for inclusion if they had typical symptoms of GERD(heartburn and/or acid regurgitation) as the major complaint in the presence or absence of accompanying atypical symptoms,such as dyspeptic symptoms and/or supraesophageal symptoms.Diagnostic and therapeutic decisions should be made based on specific recommendations of the Spanish clinical practice guideline for GERD which is a widely disseminated and well known instrument among Spanish in digestive disease specialists.RESULTS:Endoscopy was indicated in 123(41%) patients:50 with alarm symptoms,32 with age > 50 years without alarm symptom.Seventy-two patients(58.5%) had esophagitis(grade A,23,grade B,28,grade C,18,grade D,3).In the presence of alarm symptoms,endoscopy was indicated consistently with recommendations in 98% of cases.However,in the absence of alarm symptoms,endoscopy was indicated in 33% of patients > 50 years(not recommended by the guideline).Adherence for proton pump inhibitors(PPIs) therapy was 80%,but doses prescribed were lower(half) in 5% of cases and higher(double) in 15%.Adherence regarding duration of PPI therapy was 69%;duration was shorter than recommended in 1%(4 wk in esophagitis grades C-D) or longer in 30%(8 wk in esophagitis grades A-B or in patients without endoscopy).Treatment response was higher when PPI doses were consistent with guidelines,although differences were not significant(95% vs 85%).CONCLUSION:GERD guideline compliance was quite good although endoscopy was over indicated in patients > 50 years without alarm symptoms;PPIs were prescribed at higher doses and longer duration.
基金supported by the Science Foundation of Military Medical Research and Clinical Research Foundation of PLA General Hospital in China,No.2016FC-CXYY-1006(to AJS)a grant from the Application of Clinical Features of Capital City of Science and Technology Commission in China,No.Z171100001017140(to AJS)
文摘Tethered cord syndrome is a progressive disease with a typically insidious onset in infants and children, and which can lead to persistent progress of neurological deficits and a high rate of disability without timely intervention. The purpose of this study was to investigate the curative effect of microsurgery in children with different types of tethered cord syndrome. In this study, we analyzed 326 patients with tethered cord syndrome, aged from 2 months to 14 years old, who were followed for 3-36 months after microscopic surgery. Based on clinical manifestations and imaging findings, these patients were classified into five types: tight ilium terminale (53 cases), lipomyelome- ningocele (55 cases), lipomatous malformation (124 cases), postoperative adhesions (56 cases), and split cord malformation (38 cases). All patients underwent microsurgery. Curative effects were measured before and 3 months after surgery by Spina Bifida Neurological Scale based on sensory and motor functions, reflexes, and bladder and bowel function. The results showed that Spina Bifida Neurological Scale scores improved in all five types after surgery. Overall effective rates in these patients were 75%. Effective rates were 91% in tight ilium terminale, 84% in lipomyelomeningocele, 65% in lipomatous malformation, 75% in postoperative adhesion, and 79% in split cord mal- formation. Binary logistic regression analysis revealed that types of tethered cord syndrome (lipoma-type or not) and symptom duration before surgery were independent influencing factors of surgical outcome. These results show that therapeutic effect is markedly different in patients with different types of tethered cord syndrome. Suitable clinical classification for tethered cord syndrome will be helpful in predicting prognosis and guiding treatment. This trial has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800016464).
文摘Objective To investigate the clinical applications of coronary CT angiography in patients with suspected coronary artery disease and identify factors that affect CT findings. Methods Medical records of patients suspected of coronary artery disease over a period of 12 months from a tertiary teaching hospital were retrospectively reviewed. Patient age, sex (male/female), duration of symptoms and abnormal rates of coronary CT angiography scans were analysed to investigate the relationship among these parameters. The patients by age were characterized into five groups: under 36 years, 36-45 years, 46-55 years, 56455 years and more than 66 years, respectively; while the duration of symptoms was also classified into five groups: less than one week, one week to one month, one to three months, three to six months and more than six months. Results Of the 880 patient records reviewed, 800 met the above study criteria. Five hundred and forty nine patients demonstrated abnormal CT findings (68.6%). There was no significant difference in the percentage of abnormal CT findings based on patient sex and the duration of symptoms (P = 0.14). The abnormal rates of coronary CT angiography, however, increased significantly with increasing age (P 〈 0.001); with patients over 65 years of age 2.5 times more likely to have an abnormal CT scan relative to a patient under 45 years. A significant difference was found between abnormal coronary CT angiography and the duration of symptoms (P = 0.012). Conclusions Our results indicate coronary CT angiography findings are significantly related to the patient age group and duration of symptoms. Clinical referral for coronary CT angiography of patients with suspected coronary artery disease needs to be justified with regard to the judicious use of this imaging modality.
文摘Mountainous areas have been long recognized as particularly important for the planet and sustainable mountain development is a global priority. In order to improve the socioeconomic development perspectives of mountain societies, efficient and well-targeted energy strategies should be formed. An important step towards this direction is adequate understanding of local conditions and specific features that affect energy sector. This procedure allows the inclusion of "locality" in energy planning and so, decentralized energy production is facilitated. The present study attempts to determine the particular energy identity of mountainous areas. Greece, which is the second most mountainous country in the EU, has been selected as a case study. Essential features of the mountainous space have been selected, namely altitude, inclination, remoteness, lack of productive activities, old buildings/vernacular architecture, in order to explore their interrelation with the energy sector. Based on literature review and research findings the interaction between mountainous character and energy is outlined. Therefore, a framework of the characteristics of mountain energy identity is composed, which can provide support to the formation of specialized energy policy for mountainous areas. Some of the main findings of the present study include the significantly increased energy loads of mountainous areas, the abundance of renewable energy potential in high – altitude areas, the vulnerability of mountain societies to energy poverty and the difficulties in sitting energy projects in the restricted usable space of mountains. Since the literature regarding mountains and energy is rather poor the present paper aspires to be a step towards highlighting the importance of energy issues for mountain areas and societies. By determining the features of mountain energy identity energy planning in high – altitude areas and so, helping make energy planning more effective, such research works can be parts of sustainable development strategies for mountainous areas.
文摘Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually have unique shape. Its geometrical shape assumed as tapered hollow pipe. This study aims to find the effect of bamboo taper to its strength properties on center point bending test. The ratio between the Modulus of Rupture (S~) calculated in the center point, and the maximum bending stress along the beam is called strength ratio of taper (Ct). The theoretical calculation results Ct value is 1 if the taper lower than 0.023, while Ct value become lower if the taper is higher than 0.023. The survey on Ampel (Bambusa vulgaris Schrad.), Tali (Gigantochloa apus (BI. Ex Schult. f) Kurz), Gombong (Gigantochloa verticillata (Willd.) Munro), and Mayan (Gigantochloa robusta Kurz.) found that the overall taper range is -0.0047-0.0088 and 0-0.0127 for inner and outer taper respectively. On that overall range the Ct value is always 1, so it is reasonable to ignore the taper effect on one point bending test.
基金Supported by a grant from the Education Department of Sichuan Province(No.16ZA0197)
文摘Objective The most important complication after low anterior resection(LAR) for mid-low rectal cancer is symptomatic anastomotic leakage(AL). More than one-third of patients with rectal cancer who underwent LAR will have functional stomas during primary operation. The aim of this retrospective study was to evaluate the risk factors associated with clinical AL following LAR without diversional stomas.Methods Between 2012 and 2017, information about 578 consecutive patients with rectal tumors less than 12 cm from the anal verge who underwent LAR without diversional stomas by the same surgical team was collected retrospectively. A standardized extraperitonealized anastomosis and pelvic drainage were conducted for all patients during primary operations, and the outcome of interest was clinical AL. The associations between AL and 14 patient-related and surgical variables were examined by both univariate chi-square test and multivariate logistic regression analysis.Results The AL rate was 7.27%(42 of 578). Univariate and multivariate analyses showed that male sex(P = 0.018), mid-low rectal cancer(located 10 cm or less above the anal verge)(P = 0.041), presence of diabetes(odds ratio = 2.117), longer duration of operation(odds ratio = 1.890), and intraoperative contamination(odds ratio = 2.163) were risk factors of AL for LAR without diversional stoma and independently predictive of clinical AL. Nearly 83.3%(35 of 42) of leakage could be cured by persistent pelvic irrigation-suction-drainage without surgical intervention. Only 7 patients(16.7%) with severe complications, such as peritonitis, and fistula, required reoperation, and functional stoma was used as a salvage treatment.Conclusion From the findings of this retrospective survey, we identified that mid-low rectal cancer and male sex were independent risk factors for developing clinical AL after LAR without diversional stomas, as well as longer duration of operation, presence of diabetes, and contamination of the operative field. Moreover, we deemed that LAR without diversional stomas for mid-low rectal cancers was safe, effective, and feasible. Extraperitonealized anastomosis and pelvic drainage obtained a relatively low rate of AL and avoided unnecessary functional stomas. Pelvic irrigation-suction-drainage was an effective procedure to resolve AL, and functional stoma was potentially used as a salvage modality for serious leakage.
基金Supported by Grants from the National Natural Science Foundation of China(No.81560663,81773924,U1402221,81573636)Beijing Natural Science Foundation(7182114)+7 种基金PUMC Youth Fund(3332016058)CAMS Innovation Fund for Medical Sciences(CIFMS)(2016-I2M-1-004)the Scientific Research Foundation of the Higher Education Institutions of Hunan Province(15K091)Project of NDRC and State Administration of Traditional Chinese Medicine(60011000)Hunan Provincial Key Laboratory for Standardization of Important Chinese Herbal Pieces(BG201701,4981-0901020)The State Key Laboratory Fund Open Project(GTZK201610)China Postdoctoral Science Foundation(2013M540066)Beijing Key Laboratory of New Drug Mechanisms and Pharmacological Evaluation Study(BZ0150)
文摘OBJECTIVE: To investigate the antidepressant-likeeffect of active fraction of Polyrhachis vicina Roger(AFPR) in a rat depression model, and to elucidate the underlying mechanism.METHODS: AFPR was extracted with ethanol followed by petroleum ether. Its antidepressant-like effect was investigated in mice by tail suspension test(TST), forced swimming test(FST) and open field test(OPT). A repeated dose of reserpine(0.5 mg/kg, daily for 14 d) was used to establish a rat depression model. Fluoxetine was used as positive control agent. The effect of AFPR on reserpine-induced ptosis, hypothermia and akinesia, the levels of monoamines and their metabolites, and the activity of monoamine oxidase(MAO) in hippocampus and prefrontal cortex were determined.RESULTS: Administration of AFPR by gavage at 160 and 320 mg/kg significantly reduced the duration of immobility in the FST and TST, and did not affect locomotor activity in the OPT. In the reserpine-induced depression model, AFPR attenuated anhedonia, demonstrated by reversing hypothermia, akinesia and sucrose consumption. AFPR significantly increased the concentration of monoamines, including dopamine, serotonin, noradrenaline and acetylcholine.CONCLUSION: AFPR normalized the metabolism rates of noradrenaline, serotonin and dopamine,and the activity of MAO, which were altered by chronic reserpine exposure. The findings suggest that modulation of the monoaminergic neurotransmitter system likely underlies the antidepressant-like effect of AFPR.
文摘Male-male competition and female mate choice may both play important roles in driving and maintaining reproductive isolation between species. When previously allopatric species come into secondary contact with each other due to introductions, they provide an opportunity to evaluate the identity and strength of reproductive isolating mechanisms. If reproductive isolation is not maintained, hybridization may occur. We examined how reproductive isolating mechanisms medi- ate hybridization between endemic populations of the Red River pupfish Cyprinodon rubrofluviati- lis and the recently introduced sheepshead minnow C. variegatus. In lab-based dominance trials, males of both species won the same number of competitions. However, male C. rubrofluviatilis that won competitions were more aggressive than C, variegatus winners, and more aggression was needed to win against competitor C. variagatus than allopatric C. rubrofluviatilis. Duration of fights also differed based on the relatedness of the competitor. In dichotomous mate choice trials, there were no conspecific or heterospecific preferences expressed by females of either species. Our findings that male-male aggression differs between closely and distantly related groups, but female choice does not suggest that male-male competition may be the more likely mechanism to impede gene flow in this system.