In order to raise the detection precision of the extended binary phase shift keying (EBPSK) receiver, a detector based on the improved particle swarm optimization algorithm (IMPSO) and the BP neural network is des...In order to raise the detection precision of the extended binary phase shift keying (EBPSK) receiver, a detector based on the improved particle swarm optimization algorithm (IMPSO) and the BP neural network is designed. First, the characteristics of EBPSK modulated signals and the special filtering mechanism of the impacting filter are demonstrated. Secondly, an improved particle swarm optimization algorithm based on the logistic chaos disturbance operator and the Cauchy mutation operator is proposed, and the EBPSK detector is designed by utilizing the IMPSO-BP neural network. Finally, the simulation of the EBPSK detector based on the MPSO-BP neural network is conducted and the result is compared with that of the adaptive threshold-based decision, the BP neural network, and the PSO-BP detector, respectively. Simulation results show that the detection performance of the EBPSK detector based on the IMPSO-BP neural network is better than those of the other three detectors.展开更多
AIM: To determine whether efflux systems contribute to multidrug resistance of H pylori. METHODS: A chloramphenicol-induced multidrug resistance model of six susceptible H pylori strains (5 isolates and H pylori NCTC1...AIM: To determine whether efflux systems contribute to multidrug resistance of H pylori. METHODS: A chloramphenicol-induced multidrug resistance model of six susceptible H pylori strains (5 isolates and H pylori NCTC11637) was developed. Multidrug-resistant (MDR) strains were selected and the minimal inhibitory concentration (MIC) of eryth-romycin, metronidazole, penicillin G, tetracycline, and ciprofloxacin in multidrug resistant strains and their parent strains was determined by agar dilution tests. The level of mRNA expression of hefA was assessed by fluorescence real-time quantitative PCR. A H pylori LZ1026 knockout mutant (ΔH pylori LZ1026) for (puta-tive) efflux protein was constructed by inserting the kanamycin resistance cassette from pEGFP-N2 into hefA, and its susceptibility profiles to 10 antibiotics were evaluated. RESULTS: The MIC of six multidrug-resistant strains (including 5 clinical isolates and H pylori NCTC11637) increased signifi cantly (≥ 4-fold) compared with their parent strains. The expression level of hefA gene was significantly higher in the MDR strains than in their parent strains (P = 0.033). A H pylori LZ1026 mutant was successfully constructed and the ΔH pylori LZ1026 was more susceptible to four of the 10 antibiotics. All the 20 strains displayed transcripts for hefA that con-fi rmed the in vitro expression of these genes.CONCLUSION: The efflux pump gene hefA plays an important role in multidrug resistance of H pylori.展开更多
AIM:To study the safety and effectiveness of propofol sedation for outpatient colonoscopy.METHODS:Propofol was given by bolus injection with an age-adjusted standard protocol consisting of 60 mg for patients < 70 y...AIM:To study the safety and effectiveness of propofol sedation for outpatient colonoscopy.METHODS:Propofol was given by bolus injection with an age-adjusted standard protocol consisting of 60 mg for patients < 70 years old,40 mg for patients age 70-89 years,and 20 mg for those ≥ 90 years,and additional injections of 20 mg propofol were given up to a maximum of 200 mg.The principal parameters were the occurrence of adverse events within 24 h after colonoscopy and overall satisfaction for this procedure.Secondary parameters included successful procedure,respiratory depression,and other complications.RESULTS:Consecutive patients were entered prospectively and all 2101 entered successfully completed outpatient colonoscopy.The mean dose of propofol used was 96.4 mg(range 40-200 mg).Younger patients required higher doses of propofol than older patients(20-40 years vs ≥ 61 years:115.3 ± 32 mg vs 89.7 ± 21 mg,P < 0.001).Transient supplemental oxygen supply was needed by five patients(0.2%);no other complications occurred.The questionnaires were completed by 1820(87%) of 2101 patients and most rated their overall satisfaction as excellent(80%) or good(17%).The majority(65%) of patients drove home or to their office after their colonoscopy.Most(99%) were willing to repeat the same procedure.No incidents occurred within 24 h after colonoscopy.CONCLUSION:Propofol sedation using a dose < 200 mg proved both safe and practical for outpatient colonoscopy.展开更多
AIM: To investigate the tolerance development against the relaxant effect of nitric oxide donating drug isosorbide dinitrate (ISDN) and sodium nitropruside (SNP) in internal anal sphincter (IAS) smooth muscle. METHODS...AIM: To investigate the tolerance development against the relaxant effect of nitric oxide donating drug isosorbide dinitrate (ISDN) and sodium nitropruside (SNP) in internal anal sphincter (IAS) smooth muscle. METHODS: Relaxation responses of ISDN, and electrical fi eld stimulation (EFS) were obtained before and after tolerance induction by ISDN incubation. RESULTS: ISDN (10-7-10-4 mol/L) and SNP (10-8-10-4 mol/L) caused a concentration-dependent relaxation on the basal tonus of the isolated rabbit IAS strips. After a period of 2 h incubation of the 6 x 10-4 mol/L ISDN the relaxation effects of ISDN and SNP did not change compared to control strips. EFS evoked frequency-dependent relaxation in internal anal sphincter smooth muscle and Emax obtained from control strips were not changed in ISDN tolerance-inducing condition. In this study nitrate tolerance was not observed in rabbit IAS smooth muscle. CONCLUSION: This result shows that nitric oxide donating drugs relaxes the internal anal sphincter of the rabbits without the development of tolerance.展开更多
Constantine is a big city, particular because of its site and history. But it is especially a city that currently polarizes a huge interest from public authorities, researchers, as well as citizens represented by asso...Constantine is a big city, particular because of its site and history. But it is especially a city that currently polarizes a huge interest from public authorities, researchers, as well as citizens represented by associations that are militating to safeguard and promote the city. Making Constantine "a regional capital, a metropolis" is the ambitious urban project of this city authorities. It is a prestigious project, but at the same time, a double-edged sword. With the emergence of this project, a new conception of the city and its image is induced, the one that conjures new canons of urban modernity, with the whole discourse that sustains it and indicators that materialize it. A new attitude toward the current city of Constantine has emerged, from both the authorities and citizens. The inhabitants are continuing in spite of all to invest their city and do not accept that the natural process of appropriation of space may be stopped indefinitely. The author will try to expose the conflict situationof a changing city inside numerous and varied issues, as well as stakes and challenges.展开更多
Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activ...Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern.展开更多
AIM: To detect and evaluate the antibodies against Helicobacter pylori (H pylori) neutrophil-activating protein (HP-NAP) in patients with gastric cancer and other gastroduodenal diseases.METHODS: Recombinant HP-...AIM: To detect and evaluate the antibodies against Helicobacter pylori (H pylori) neutrophil-activating protein (HP-NAP) in patients with gastric cancer and other gastroduodenal diseases.METHODS: Recombinant HP-NAP was prepared from a prokaryotic expression system in Escherichia coll. Serum positivity and level of HP-NAP-specific antibodies in sera from 43 patients with gastric cancer, 28 with chronic gastritis, 28 with peptic ulcer, and 89 healthy controls were measured by rHP-NAP-based ELISA. rHP-NAP-stimulated production of interleukin-8 (IL-8) and growth-related oncogene (GROα) cytokines in the culture supernatant of SGC7901 gastric epithelial cells was also detected.RESULTS: The serum positivity and mean absorbancevalue of HP-NAP-specific antibodies in the gastriccancer group (97.7% and 1.01 ± 0.24) were significantly higher than those in the chronic gastritisgroup (85.7% and 0.89 ± 0.14, P 〈 0.005) and healthy control group (27.7% and 0.65 ± 0.18, P 〈 0.001). The sensitivity and specificity of ELISA for the detection of HP-NAP-specific antibodies were 95.5% and 91.5%, respectively. HP-NAP could slightly upregulate IL-8 production in gastric epithelial cell lines but had no effect on GROα production.CONCLUSION: Infection with virulent H py/ori strains secreting HP-NAP is associated with severe gastroduodenal diseases, and HP-NAP may play a role in the development of gastric carcinoma, rHP-NAP- based ELISA can be used as a new method to detect H pylori infection. The direct effect of HP-NAP on gastric epithelial cells may be limited, but HP-NAP may contribute to inflammatory response or carcinogenesis by activating neutrophils.展开更多
OBJECTIVE: To explore the characteristics of Helicobacter pylori (H. pylori) antigen in serum and to evaluate its clinical diagnostic value. METHODS: Enzyme-linked immunosorbant assay (ELISA) was developed to detect t...OBJECTIVE: To explore the characteristics of Helicobacter pylori (H. pylori) antigen in serum and to evaluate its clinical diagnostic value. METHODS: Enzyme-linked immunosorbant assay (ELISA) was developed to detect the soluble H. pylori antigen (S-Hp) and circulatory specific H. pylori antigen immunocomplexes (Hp-IC) in serum. RESULTS: The positive rate of S-Hp was 90.91% from 66 patients with H. pylori infection, which was much greater than 0% found in 28 controls (P展开更多
We present a new normal basis multiplication scheme using a multiplexer-based algorithm. In this algorithm, the proposed multiplier processes in parallel and has a multiplexer-based structure that uses MUX and XOR gat...We present a new normal basis multiplication scheme using a multiplexer-based algorithm. In this algorithm, the proposed multiplier processes in parallel and has a multiplexer-based structure that uses MUX and XOR gates instead of AND and XOR gates. We show that our multiplier for type-1 and type-2 normal bases saves about 8% and 16%, respectively, in space complexity as compared to existing normal basis multipliers. Finally, the proposed architecture has regular and modular con-figurations and is well suited to VLSI implementations.展开更多
In this paper, variations of shear wave splitting in the 2013 Lushan Ms7.0 earthquake sequence were studied. By analyzing shear wave particle motion of local events in the shear wave window, the fast polarization dire...In this paper, variations of shear wave splitting in the 2013 Lushan Ms7.0 earthquake sequence were studied. By analyzing shear wave particle motion of local events in the shear wave window, the fast polarization directions and the delay time between fast and slow shear waves were derived from seismic recordings at eight stations on the southern segment of the Longmenshan fault zone. In the study region, the fast polarization directions show partition characteristics from south to north. And the systematic changes of the time delays between two split shear waves were also observed. As for spatial distribution, the NE fast polarization directions are consistent with the Longmenshan fault strike in the south of focal region, whereas the NW fast direction is parallel to the direction of regional principal compressive stress in the north of focal region. Stations BAX and TQU are respectively located on the Central and Front-range faults, and because of the direct influence of these faults, the fast directions at both stations show particularity. In time domain, after the main shock, the delay times at stations increased rapidly, and decreased after a period of time. Shear-wave splitting was caused mostly by stress-aligned microcracks in rock below the stations. The results demonstrate changes of local stress field during the main shock and the aftershocks. The stress on the Lushan Ms7.0 earthquake region increased after the main shock, with the stress release caused by the aftershocks and the stress reduced in the late stage.展开更多
The origin of the anomalous transport feature appearing at a conductance G 0.7× (2e2/h) in quasi-lD ballistic devices-the so-called 0.7 anomaly-represents a long standing puzzle. Several mechanisms have been pr...The origin of the anomalous transport feature appearing at a conductance G 0.7× (2e2/h) in quasi-lD ballistic devices-the so-called 0.7 anomaly-represents a long standing puzzle. Several mechanisms have been proposed to explain it, but a general consensus has not been achieved. Proposed explanations have been based on quantum interference, the Kondo effect, Wigner crystallization, and other phenomena. A key open issue is whether the point defects that can occur in these low-dimensional devices are the physical cause behind this conductance anomaly. Here we adopt a scanning gate microscopy technique to map individual impurity positions in several quasi-lD constrictions and correlate these with conductance characteristics. Our data demonstrate that the 0.7 anomaly can be observed irrespective of the presence of localized defects, and we conclude that the 0.7 anomaly is a fundamental property of low-dimensional systems.展开更多
The prenatal hormonal environment plays an important role in organizing sex differences in the morphology, physiology and behavior of humans as well as other vertebrates. Currently, all related research on rodents has...The prenatal hormonal environment plays an important role in organizing sex differences in the morphology, physiology and behavior of humans as well as other vertebrates. Currently, all related research on rodents has been focused on Myomorpha. This study presents data on sex differences in the anogenital distance (AGD) and the ratio of the second to the fourth digit length (2D:4D) from 44 wild David's rock squirrels Sciurotamias davidianus captured from the Qinling Mountains, China. This was the first study of a species from Sciuromorpha. The AGD as well as body mass are sexually dimorphic. There are no sex differences or lateral asymmetry in 2D:4D. Significant correlation was not found between AGD and 2D:4D for any paw. The findings indicate that 2D:4D may not be fixed or influenced by the prenatal steroidal environment in David's rock squirrels [Current Zoology 60 (2): 180-185, 2014].展开更多
基金The National Natural Science Foundation of China (No.60872075)the National High Technology Research and Development Program of China (863 Program) (No. 2008AA01Z227)
文摘In order to raise the detection precision of the extended binary phase shift keying (EBPSK) receiver, a detector based on the improved particle swarm optimization algorithm (IMPSO) and the BP neural network is designed. First, the characteristics of EBPSK modulated signals and the special filtering mechanism of the impacting filter are demonstrated. Secondly, an improved particle swarm optimization algorithm based on the logistic chaos disturbance operator and the Cauchy mutation operator is proposed, and the EBPSK detector is designed by utilizing the IMPSO-BP neural network. Finally, the simulation of the EBPSK detector based on the MPSO-BP neural network is conducted and the result is compared with that of the adaptive threshold-based decision, the BP neural network, and the PSO-BP detector, respectively. Simulation results show that the detection performance of the EBPSK detector based on the IMPSO-BP neural network is better than those of the other three detectors.
文摘AIM: To determine whether efflux systems contribute to multidrug resistance of H pylori. METHODS: A chloramphenicol-induced multidrug resistance model of six susceptible H pylori strains (5 isolates and H pylori NCTC11637) was developed. Multidrug-resistant (MDR) strains were selected and the minimal inhibitory concentration (MIC) of eryth-romycin, metronidazole, penicillin G, tetracycline, and ciprofloxacin in multidrug resistant strains and their parent strains was determined by agar dilution tests. The level of mRNA expression of hefA was assessed by fluorescence real-time quantitative PCR. A H pylori LZ1026 knockout mutant (ΔH pylori LZ1026) for (puta-tive) efflux protein was constructed by inserting the kanamycin resistance cassette from pEGFP-N2 into hefA, and its susceptibility profiles to 10 antibiotics were evaluated. RESULTS: The MIC of six multidrug-resistant strains (including 5 clinical isolates and H pylori NCTC11637) increased signifi cantly (≥ 4-fold) compared with their parent strains. The expression level of hefA gene was significantly higher in the MDR strains than in their parent strains (P = 0.033). A H pylori LZ1026 mutant was successfully constructed and the ΔH pylori LZ1026 was more susceptible to four of the 10 antibiotics. All the 20 strains displayed transcripts for hefA that con-fi rmed the in vitro expression of these genes.CONCLUSION: The efflux pump gene hefA plays an important role in multidrug resistance of H pylori.
文摘AIM:To study the safety and effectiveness of propofol sedation for outpatient colonoscopy.METHODS:Propofol was given by bolus injection with an age-adjusted standard protocol consisting of 60 mg for patients < 70 years old,40 mg for patients age 70-89 years,and 20 mg for those ≥ 90 years,and additional injections of 20 mg propofol were given up to a maximum of 200 mg.The principal parameters were the occurrence of adverse events within 24 h after colonoscopy and overall satisfaction for this procedure.Secondary parameters included successful procedure,respiratory depression,and other complications.RESULTS:Consecutive patients were entered prospectively and all 2101 entered successfully completed outpatient colonoscopy.The mean dose of propofol used was 96.4 mg(range 40-200 mg).Younger patients required higher doses of propofol than older patients(20-40 years vs ≥ 61 years:115.3 ± 32 mg vs 89.7 ± 21 mg,P < 0.001).Transient supplemental oxygen supply was needed by five patients(0.2%);no other complications occurred.The questionnaires were completed by 1820(87%) of 2101 patients and most rated their overall satisfaction as excellent(80%) or good(17%).The majority(65%) of patients drove home or to their office after their colonoscopy.Most(99%) were willing to repeat the same procedure.No incidents occurred within 24 h after colonoscopy.CONCLUSION:Propofol sedation using a dose < 200 mg proved both safe and practical for outpatient colonoscopy.
文摘AIM: To investigate the tolerance development against the relaxant effect of nitric oxide donating drug isosorbide dinitrate (ISDN) and sodium nitropruside (SNP) in internal anal sphincter (IAS) smooth muscle. METHODS: Relaxation responses of ISDN, and electrical fi eld stimulation (EFS) were obtained before and after tolerance induction by ISDN incubation. RESULTS: ISDN (10-7-10-4 mol/L) and SNP (10-8-10-4 mol/L) caused a concentration-dependent relaxation on the basal tonus of the isolated rabbit IAS strips. After a period of 2 h incubation of the 6 x 10-4 mol/L ISDN the relaxation effects of ISDN and SNP did not change compared to control strips. EFS evoked frequency-dependent relaxation in internal anal sphincter smooth muscle and Emax obtained from control strips were not changed in ISDN tolerance-inducing condition. In this study nitrate tolerance was not observed in rabbit IAS smooth muscle. CONCLUSION: This result shows that nitric oxide donating drugs relaxes the internal anal sphincter of the rabbits without the development of tolerance.
文摘Constantine is a big city, particular because of its site and history. But it is especially a city that currently polarizes a huge interest from public authorities, researchers, as well as citizens represented by associations that are militating to safeguard and promote the city. Making Constantine "a regional capital, a metropolis" is the ambitious urban project of this city authorities. It is a prestigious project, but at the same time, a double-edged sword. With the emergence of this project, a new conception of the city and its image is induced, the one that conjures new canons of urban modernity, with the whole discourse that sustains it and indicators that materialize it. A new attitude toward the current city of Constantine has emerged, from both the authorities and citizens. The inhabitants are continuing in spite of all to invest their city and do not accept that the natural process of appropriation of space may be stopped indefinitely. The author will try to expose the conflict situationof a changing city inside numerous and varied issues, as well as stakes and challenges.
基金Under the auspices of National 'Eleventh Five-Year Plan' Science and Technology Support Project (No. 2009BADB2B0302)Science and Technology Major Project of Fujian Province,the European Union Seventh Framework Project (No. 247608)
文摘Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern.
基金Supported by Grants from Guangdong Natural Science Foundation Project,5004750National Key Development Project,973 Program 2002CB513206
文摘AIM: To detect and evaluate the antibodies against Helicobacter pylori (H pylori) neutrophil-activating protein (HP-NAP) in patients with gastric cancer and other gastroduodenal diseases.METHODS: Recombinant HP-NAP was prepared from a prokaryotic expression system in Escherichia coll. Serum positivity and level of HP-NAP-specific antibodies in sera from 43 patients with gastric cancer, 28 with chronic gastritis, 28 with peptic ulcer, and 89 healthy controls were measured by rHP-NAP-based ELISA. rHP-NAP-stimulated production of interleukin-8 (IL-8) and growth-related oncogene (GROα) cytokines in the culture supernatant of SGC7901 gastric epithelial cells was also detected.RESULTS: The serum positivity and mean absorbancevalue of HP-NAP-specific antibodies in the gastriccancer group (97.7% and 1.01 ± 0.24) were significantly higher than those in the chronic gastritisgroup (85.7% and 0.89 ± 0.14, P 〈 0.005) and healthy control group (27.7% and 0.65 ± 0.18, P 〈 0.001). The sensitivity and specificity of ELISA for the detection of HP-NAP-specific antibodies were 95.5% and 91.5%, respectively. HP-NAP could slightly upregulate IL-8 production in gastric epithelial cell lines but had no effect on GROα production.CONCLUSION: Infection with virulent H py/ori strains secreting HP-NAP is associated with severe gastroduodenal diseases, and HP-NAP may play a role in the development of gastric carcinoma, rHP-NAP- based ELISA can be used as a new method to detect H pylori infection. The direct effect of HP-NAP on gastric epithelial cells may be limited, but HP-NAP may contribute to inflammatory response or carcinogenesis by activating neutrophils.
文摘OBJECTIVE: To explore the characteristics of Helicobacter pylori (H. pylori) antigen in serum and to evaluate its clinical diagnostic value. METHODS: Enzyme-linked immunosorbant assay (ELISA) was developed to detect the soluble H. pylori antigen (S-Hp) and circulatory specific H. pylori antigen immunocomplexes (Hp-IC) in serum. RESULTS: The positive rate of S-Hp was 90.91% from 66 patients with H. pylori infection, which was much greater than 0% found in 28 controls (P
文摘We present a new normal basis multiplication scheme using a multiplexer-based algorithm. In this algorithm, the proposed multiplier processes in parallel and has a multiplexer-based structure that uses MUX and XOR gates instead of AND and XOR gates. We show that our multiplier for type-1 and type-2 normal bases saves about 8% and 16%, respectively, in space complexity as compared to existing normal basis multipliers. Finally, the proposed architecture has regular and modular con-figurations and is well suited to VLSI implementations.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40904023, 41274063 and 41174070)Scientific Investigation of April 20, 2013 M7.0 Sichuan Lushan Earthquake
文摘In this paper, variations of shear wave splitting in the 2013 Lushan Ms7.0 earthquake sequence were studied. By analyzing shear wave particle motion of local events in the shear wave window, the fast polarization directions and the delay time between fast and slow shear waves were derived from seismic recordings at eight stations on the southern segment of the Longmenshan fault zone. In the study region, the fast polarization directions show partition characteristics from south to north. And the systematic changes of the time delays between two split shear waves were also observed. As for spatial distribution, the NE fast polarization directions are consistent with the Longmenshan fault strike in the south of focal region, whereas the NW fast direction is parallel to the direction of regional principal compressive stress in the north of focal region. Stations BAX and TQU are respectively located on the Central and Front-range faults, and because of the direct influence of these faults, the fast directions at both stations show particularity. In time domain, after the main shock, the delay times at stations increased rapidly, and decreased after a period of time. Shear-wave splitting was caused mostly by stress-aligned microcracks in rock below the stations. The results demonstrate changes of local stress field during the main shock and the aftershocks. The stress on the Lushan Ms7.0 earthquake region increased after the main shock, with the stress release caused by the aftershocks and the stress reduced in the late stage.
基金This work was supported by the Italian Ministry of Research (Ministero dell'Istruzione, dell'Universitae della Ricerca (MIUR)-Fondo per gli Investimenti della Ricerca di Base (FIRB) project No. RBID08B3FM) and by the Italian Ministry of Foreign Affairs (Ministero degli Affari Esteri, Direzione Generale per la Promozione del Sistema Paese, progetto: Nanoelettronica quantistica per le tecnologie delle informazioni). Two of us (C.R. and W.W.) thank the Swiss National Science Foundation (SNSF) financial support.
文摘The origin of the anomalous transport feature appearing at a conductance G 0.7× (2e2/h) in quasi-lD ballistic devices-the so-called 0.7 anomaly-represents a long standing puzzle. Several mechanisms have been proposed to explain it, but a general consensus has not been achieved. Proposed explanations have been based on quantum interference, the Kondo effect, Wigner crystallization, and other phenomena. A key open issue is whether the point defects that can occur in these low-dimensional devices are the physical cause behind this conductance anomaly. Here we adopt a scanning gate microscopy technique to map individual impurity positions in several quasi-lD constrictions and correlate these with conductance characteristics. Our data demonstrate that the 0.7 anomaly can be observed irrespective of the presence of localized defects, and we conclude that the 0.7 anomaly is a fundamental property of low-dimensional systems.
文摘The prenatal hormonal environment plays an important role in organizing sex differences in the morphology, physiology and behavior of humans as well as other vertebrates. Currently, all related research on rodents has been focused on Myomorpha. This study presents data on sex differences in the anogenital distance (AGD) and the ratio of the second to the fourth digit length (2D:4D) from 44 wild David's rock squirrels Sciurotamias davidianus captured from the Qinling Mountains, China. This was the first study of a species from Sciuromorpha. The AGD as well as body mass are sexually dimorphic. There are no sex differences or lateral asymmetry in 2D:4D. Significant correlation was not found between AGD and 2D:4D for any paw. The findings indicate that 2D:4D may not be fixed or influenced by the prenatal steroidal environment in David's rock squirrels [Current Zoology 60 (2): 180-185, 2014].