A robust digital predistortion(DPD)technique utilizing negative feedback iteration is introduced for linearizing power amplifiers(PAs)in long term evolution(LTE)/5G systems.Different from the conventional direct learn...A robust digital predistortion(DPD)technique utilizing negative feedback iteration is introduced for linearizing power amplifiers(PAs)in long term evolution(LTE)/5G systems.Different from the conventional direct learning and indirect learning structure,the proposed DPD suggests a two-step method to identify the predistortion.Firstly,a negative feedback based iteration is used to estimate the optimal DPD signal.Then the corresponding DPD parameters are extracted by forward modeling with the input signal and optimal DPD signal.The iteration can be applied to both single-band and dual-band PAs,which will achieve superior linear performance than the conventional direct learning DPD while having a relatively low computational complexity.The measurement is carried out on a broadband Doherty PA(DPA)with a 200 MHz bandwidth LTE signal at 2.1 GHz,and on a 5G DPA with two 10 MHz LTE signals at 3.4/3.6 GHz for validation in dual-band scenarios.展开更多
Waveform control method was commonly adopted to reduce the spatter of CO2 arc welding and improve the weld formation. It certainly would reduce the self-regulation ability of arc due to the adoption of segmented const...Waveform control method was commonly adopted to reduce the spatter of CO2 arc welding and improve the weld formation. It certainly would reduce the self-regulation ability of arc due to the adoption of segmented constant current control which especially led to arc" blowout with the abrupt change oat" arc" length or downward welding. Therefore alterative wire-feed system based on arc voltage negative feedback was put forward to improve the .stability of arc" length in this paper. Double closed-loop and double fuzzy P1 regulation were adopted in this system. Fuzzy control of induced voltage was adopted in the inner-loop which improved the stability and fast response of wire-feed system. Fuzz)" control of arc" voltage negative feedback was used in the outer-loop whose output .served as the input of negative feedback regulation of inner-loop induced voltage. This method could remain arc" length and weld penetration unchan, ged on the basils of reducing spatter and improving formation and it was proved by downward welding tests.展开更多
One of the ingredients of the anthropogenic global warming hypothesis is the existence of large positive feedback in the climate system. An example is polar ice that, once melted, turns into blacker water that will in...One of the ingredients of the anthropogenic global warming hypothesis is the existence of large positive feedback in the climate system. An example is polar ice that, once melted, turns into blacker water that will increase radiation absorption and this rein-forces the melting. This causes a run-away scenario with a point of no return. Here it is shown that the polar ice can also have negative feedback aspects, where a melting of polar ice will cause it to reappear.展开更多
Over the past three decades, neurophysiologists studying the neural circuitry responsible for control of skeletal muscles have developed several different general theories of sensorimotor control. These have usually i...Over the past three decades, neurophysiologists studying the neural circuitry responsible for control of skeletal muscles have developed several different general theories of sensorimotor control. These have usually invoked one or more of the sources of proprioceptive signals (e.g. muscle spindle and Golgi tendon organ afferents) in positive or negative feed-back loops to the homonymous alpha motoneurones. In this paper we consider to analyze the role of posi-tive feedback in combination of negative feedback due to important role of them in stabilizing the neu-romuscular system.展开更多
The design and fabrication of an ultra-broadband power amplifier based on a GaN HEMT, which operates in the frequency range from 3 to 8 GHz, is presented in this paper. A TGF2023-02 GaN HEMT chip from Tri Quint is ado...The design and fabrication of an ultra-broadband power amplifier based on a GaN HEMT, which operates in the frequency range from 3 to 8 GHz, is presented in this paper. A TGF2023-02 GaN HEMT chip from Tri Quint is adopted and modeled. A novel negative feedback structure is applied in the circuit. The measured results show that the amplifier module has a wide range frequency response that is almost consistent with those of simulation at frequencies from 3 to 6.5 GHz. The measured power gain is greater than 7 dB between 3 and 6.5 GHz.The saturated output power is 38.5 dBm under DC bias of Vds =D28 V, Vgs D =-3:5 V at the frequency of 5.5 GHz.展开更多
In this study, the temporal structure of the variation of North Atlantic Oscillation (NAO) and its impact on regional climate variability are analyzed using various datasets. The results show that blocking formation...In this study, the temporal structure of the variation of North Atlantic Oscillation (NAO) and its impact on regional climate variability are analyzed using various datasets. The results show that blocking formations in the Atlantic region are sensitive to the phase of the NAO. Sixty-seven percent more winter blocking days are observed during the negative phase compared to the positive phase of the NAO. The average length of blocking during the negative phase is about 11 days, which is nearly twice as long as the 6-day length observed during the positive phase of the NAO. The NAO-related differences in blocking frequency and persistence are associated with changes in the distribution of the surface air temperature anomaly, which, to a large extent, is determined by the phase of the NAO. The distribution of regional cloud amount is also sensitive to the phase of the NAO. For the negative phase, the cloud amounts are significant, positive anomalies in the convective zone in the Tropics and much less cloudiness in the mid latitudes. But for the positive phase of the NAO, the cloud amount is much higher in the mid-latitude storm track region. In the whole Atlantic region, the cloud amount shows a decrease with the increase of surface air temperature. These results suggest that there may be a negative feedback between the cloud amount and the surface air t.emperature in the Atlantic region.展开更多
AIM: To investigate executive function in Japanese adolescents and adults with autism spectrum disorders(ASD) compared to Japanese controls.METHODS: Thirty-three individuals with ASD and 33 controls participated. The ...AIM: To investigate executive function in Japanese adolescents and adults with autism spectrum disorders(ASD) compared to Japanese controls.METHODS: Thirty-three individuals with ASD and 33 controls participated. The ASD and control groups' demographic variables were matched for gender(male/female: 20/13 vs 20/13), age(26.1 ± 11.5 vs 26.8 ± 9.6), years of education(13.2 ± 2.9 vs 14.2 ± 1.9), full-scale intelligence quotient(IQ)(103.0 ± 16.7 vs 103.7 ± 14.7), performance IQ(96.2 ± 16.1 vs 97.8 ± 15.0), and verbal IQ(107.9 ± 16.3 vs 107.7 ± 14.4). Participants performed the Wisconsin Card Sorting Test(WCST), which assesses the executive processes involved in problem solving and cognitive flexibility, and the Continuous Performance Test(CPT), which assesses attention and impulsivity. Symptoms were assessed by the Autism-Spectrum Quotient Japanese version(AQ-J). First, we compared the scores of the WCST between the groups using a Mann-Whitney U-test and conducted an analysis of covariance for the variables with the scores of category archives and CPT scores as covariates. Second, we analyzed the correlation between the scores of the WCST and the AQ-J in the ASD group using Pearson's r.RESULTS: The total errors(TE) and the percentages of perseverative errors of the Milner type(%PEM) and Nelson type(%PEN) among the TE in the ASD group were significantly worse compared with the control group(ASD vs Control, respectively: TE: 16.0 ± 6.2 vs 12.6 ± 3.5, P = 0.012; %PEM: 11.7 ± 10.7 vs 6.6 ± 8.9, P = 0.037; %PEN: 20.1 ± 14.5 vs 8.7 ± 10.4, P = 0.0011). In contrast, no significant difference was observed between the two groups in the scores of categories achieved on the WCST or the CPT. An analysis of covariance revealed significant differences between the groups in the %PEN scores(P = 0.0062) but not in the TE or the %PEM scores. These results suggest that Japanese adolescents and adults with ASD have cognitive inflexibility. Furthermore, our results suggest that Japanese adolescents and adults with ASD may have difficulties using negative feedback because perseverative errors of the Nelson type indicate persistence in choosing the incorrect reaction. By contrast, there was no significant correlation between the WCST and AQ-J scores.CONCLUSION: We confirmed the presence of cognitive inflexibility in Japanese adolescents and adults with ASD. Our results also indicated that subjects with ASD may not use negative feedback effectively.展开更多
According to different applications,the performance parameters of the several Geo-Electromagnetic Magnetic Induction Sensors( GEMISs) which are the most representative in the world are compared. After discussing the s...According to different applications,the performance parameters of the several Geo-Electromagnetic Magnetic Induction Sensors( GEMISs) which are the most representative in the world are compared. After discussing the several key technologies for improving the performance of GEMISs,the main conclusions are as follows: the application bandwidth can be expanded by adopting flux negative feedback( 1 m Hz-10 k Hz);"laminated"core structure is useful for suppressing eddy current loss; the effective permeability of the core has increased observably after adding flux concentrators to the two ends of the core; the chopper amplifier is a useful method to suppress 1/f noise for reducing the GEMIS's output noise; the indoor calibration scheme based on"long straight solenoid"proposed to obtain sensor sensitivity. Accordingly,the problem how to reduce the noise of GEMIS is urgent need to be solved,which will improve the performance of GEMIS. And there is plenty of work requires further study on parameters ' optimization of coil and core. In the future,miniaturization,intelligence and three-axis measurement are the development directions of GEMIS.展开更多
It is considered three phases of development of a tropical cyclone: the origin, the steady-state regime and the termination, coinciding with three phases of self-oscillatory process: oscillation buid-up, dynamic balan...It is considered three phases of development of a tropical cyclone: the origin, the steady-state regime and the termination, coinciding with three phases of self-oscillatory process: oscillation buid-up, dynamic balance and failure of self-oscillations. The rough size of energy of a cyclone, as column of air rotating with high speed, at initial and final stages of development and comparison of the received sizes with nuclear and hydrogen bombs is calculated. The model of the electronic oscillator with negative active conductivity by the numerical solution of the equation of the Van-der-Pol is analyzed. Formal coincidence of transient in this model with increase of capacity of vortical air formation, that allows to make mnemonic model of a cyclone in the form of volume self-oscillatory system is shown. The numerical solution of the made equations allows to construct schedules of dynamic process for each of particles of the investigated environment. The general recipe on restraint of development of a cyclone by compulsory entering into it of attenuation is given. Realization of this recipe by means of group of platforms with powerful wind-electrogenerator and the fans and uses of a principle of negative feedback is shown. The results of laboratory experiment confirming idea, taken as a principle struggle against an arising air whirlwind, by transformation of a laminar stream in chaotic, turbulent are resulted. For fuller check offered a wind-energetic method of struggle against a cyclone carrying out of more scale experiment is necessary.展开更多
The design and performances of a high dynamic range DC-AC current sensor utilizing Giant Magneto-Impedance (GMI) are presented. The sensor is based on a GMI element with negative feedback. The sensing element is a 30 ...The design and performances of a high dynamic range DC-AC current sensor utilizing Giant Magneto-Impedance (GMI) are presented. The sensor is based on a GMI element with negative feedback. The sensing element is a 30 μm diameter GMI Co-based amorphous wire. It is curled to a toroidal core of 2 cm diameter. A bias magnetic field of about 650 A/m is applied to the GMI element to obtain an asymmetric GMI effect. A strong negative feedback is introduced to ensure linearity in a wide dynamic range. Analog conditioning electronics was fully developed. This includes a square wave oscillator based on an inverter trigger;a peak detector and a high gain amplifier with zero adjust. The GMI element is driven at a 3 MHz frequency and 5 mA peak-to-peak current. The closed-loop operations are investigated and the performances of the sensor are presented. DC current measurements are performed. The sensor exhibits good sensitivity and very good linearity, free from hysteresis, in a wide dynamic range of ±40 A. The sensitivity is about 0.24 V/A and the linearity error is about 0.02% of the full scale (FS). The hysteresis error is smaller than the measurement accuracy. AC current measurements using the developed sensor have also been successfully achieved. The sensor bandwidth in closed-loop was about 1.7 kHz.展开更多
It is observed by in situ stain that LDH (1 5) ...nNAD + can probably enter the nucleopore and can be bound bound specifically with the genes that encode them. During the in vitro expression, the dilution of heart nuc...It is observed by in situ stain that LDH (1 5) ...nNAD + can probably enter the nucleopore and can be bound bound specifically with the genes that encode them. During the in vitro expression, the dilution of heart nuclear DNA fragments could enhance the expression activity of LDH/DNA and the amount of expressed LDH (1 5) is in proportion to the amount of dissociable LDH (1 5) on the LDH/DNA. With the integration of 14C Leu to the proteins, it is also observed that the addition of LDH (1 5) ...nNAD + can suppress the in vitro expression activity of LDH/DNA. AFM observation shows that the regulation sequence at the both ends of active genes may be bound with such active factors as proteins encoded by the genes which probably is the main molecular switch of gene expression and regulation we have been always searching for. Our work shows the prospective application of the combination of AFM and isotope labeling in the research of biological reaction.展开更多
Although both protein arginine methylation(PRMT)and jasmonate(JA)signaling are crucial for regulating plant development,the relationship between these processes in the control of spikelet development remains unclear.I...Although both protein arginine methylation(PRMT)and jasmonate(JA)signaling are crucial for regulating plant development,the relationship between these processes in the control of spikelet development remains unclear.In this study,we used the CRISPR/Cas9 technology to generate two OsPRMT6a loss-of-function mutants that exhibit various abnormal spikelet structures.Interestingly,we found that OsPRMT6a can methylate arginine residues in JA signal repressors OsJAZ1 and OsJAZ7.We showed that arginine methylation of OsJAZ1 enhances the binding affinity of OsJAZ1 with the JA receptors OsCOI1a and OsCOI1b in the presence of JAs,thereby promoting the ubiquitination of OsJAZ1 by the SCF^(OsCOI1a/OsCOI1b) complex and degradation via the 26S proteasome.This process ultimately releases OsMYC2,a core transcriptional regulator in the JA signaling pathway,to activate or repress JA-responsive genes,thereby maintaining normal plant(spikelet)development.However,in the osprmt6a-1 mutant,reduced arginine methylation of OsJAZ1 impaires the interaction between OsJAZ1 and OsCOI1a/OsCOI1b in the presence of JAs.As a result,OsJAZ1 proteins become more stable,repressing JA responses,thus causing the formation of abnormal spikelet structures.Moreover,we discovered that JA signaling reduces the OsPRMT6a mRNA level in an OsMYC2-dependent manner,thereby establishing a negative feedback loop to balance JA signaling.We further found that OsPRMT6a-mediated arginine methylation of OsJAZ1 likely serves as a switch to tune JA signaling to maintain normal spikelet development under harsh environmental conditions such as high temperatures.Collectively,our study establishes a direct molecular link between arginine methylation and JA signaling in rice.展开更多
Phytohormone ethylene plays pivotal roles in plant response to developmental and environmental signals. During the past few years, the emerging evidence has led us to a new understanding of the signaling mechanisms an...Phytohormone ethylene plays pivotal roles in plant response to developmental and environmental signals. During the past few years, the emerging evidence has led us to a new understanding of the signaling mechanisms and regulatory networks of the ethylene action. In this review, we focus on the major advances made in the past three years, particularly the findings leading to new paradigms and the observations under debate. With the recent demonstration of the regulation of the protein stability of numerous key signaling components including EIN3, ELL1, EIN2, ETR2, EBFI/EBF2, and ETPI/ETP2, we highlight proteasome-dependent protein degradation as an essential regulatory mechanism that is widely adopted in the ethylene signaling pathway. We also discuss the implication of the negative feedback mechanism in the ethylene signaling pathway in light of ethylene-induced ETR2 and EBF2 gene expression. Meanwhile, we summarize the controversy on the involvement of MKK9-MPK3/6 cascade in the ethylene signaling versus biosynthesis pathway, and discuss the possible role of this MAPK module in the ethylene action. Finally, we describe the complex interactions between ethylene and other signaling pathways including auxin, light, and plant innate immunity, and propose that EIN3/ EIL1 act as a convergence point in the ethylene-initiated signaling network.展开更多
Symbiotic root nodules are root lateral organs of plants in which nitrogen-fixing bacteria(rhizobia)convert atmospheric nitrogen to ammonia.The formation and number of nodules in legumes are precisely controlled by a ...Symbiotic root nodules are root lateral organs of plants in which nitrogen-fixing bacteria(rhizobia)convert atmospheric nitrogen to ammonia.The formation and number of nodules in legumes are precisely controlled by a rhizobia-induced signal cascade and host-controlled autoregulation of nodulation(AON).However,how these pathways are integrated and their underlying mechanisms are unclear.Here,we report that microRNA172c(miR172c)activates soybean(Glycine max)R hizobia-induced CLE1(GmRICI)and GmRIC2 by removing the transcriptional repression of these genes by Nodule Number Control 1(NNC1),leading to the activation of the AON pathway.NNC1 interacts with GmNINa,the soybean ortholog of Lotus NODULE INCEPTION(NIN),and hampers its transcriptional activation o i G m RICI and GmRIC2.Importantly,GmNINa acts as a transcriptional activator of miR172c.Intriguingly,NNC1 can transcriptionally repress miR172c expression,adding a negative feedback loop into the NNC1 regulatory network.Moreover,GmNINa interacts with NNC1 and can relieve the NNC1-mediated repression of miR172c transcription.Thus,the GmNINa-miR172c-NNC1 network is a master switch that coordinately regulates and optimizes NF and AON signaling,supporting the balance between nodulation and AON in soybean.展开更多
apamvcin was first isolated from a strain of Sreptomyces hygroscopicus in the early 1970s froma soil sample taken on Easter Island. Because the antiproliferative effects of rapamycin on yeast cell, as well as B and T ...apamvcin was first isolated from a strain of Sreptomyces hygroscopicus in the early 1970s froma soil sample taken on Easter Island. Because the antiproliferative effects of rapamycin on yeast cell, as well as B and T lymphocytes, it was first identified as an antimicrobial agent with potent immunosuppressive activity and has been used in antirejection therapy.展开更多
Hippo signaling plays a crucial role in growth control and tumor suppression by regulating cell proliferation,apoptosis,and differentiation.How Hippo signaling is regulated has been under extensive investigation.Over ...Hippo signaling plays a crucial role in growth control and tumor suppression by regulating cell proliferation,apoptosis,and differentiation.How Hippo signaling is regulated has been under extensive investigation.Over the past three years,an increasing amount of data have supported a model of actin cytoskeleton blocking Hippo signaling activity to allow nuclear accumulation of a downstream effector,Yki/Yap/Taz.On the other hand,Hippo signaling negatively regulates actin cytoskeleton organization.This review p rovides insight on the mutual regulatory mechanisms between Hippo signaling and actin cytoskeleton for a tight control of cell behaviors during animal development,and points out outstanding questions for further investigations.展开更多
A fully integrated 40 Gbit/s optical receiver analog front-end (AFE) including a transimpedance amplifier (TIA) and a limiting amplifier (LA) for short distance communication is described in this paper. The prop...A fully integrated 40 Gbit/s optical receiver analog front-end (AFE) including a transimpedance amplifier (TIA) and a limiting amplifier (LA) for short distance communication is described in this paper. The proposed TIA employs a modified regulated cascode (RGC) configuration as input stage, and adopts a third order interleaving active feedback gain stage. The LA utilizes nested active feedback, negative capacitance, and inductor peaking technology to achieve high voltage gain and wide bandwidth. The tiny photo current received by the receiver AFE is amplified to a single-ended voltage swing of 200 mV(p-p). Simulation results show that the receiver AFE provides conversion gain of up to 83 dBΩ and bandwidth of 34.7 GHz, and the equivalent input noise current integrated from 1 MHz to 30 GHz is about 6.6 μA(rms).展开更多
(i) The structure and function of the meridian (channel and collateral) described by ancient medical doctors may correspond to the blood circulation, nerve control and neurohumoral modulation of modern medicine. (ii) ...(i) The structure and function of the meridian (channel and collateral) described by ancient medical doctors may correspond to the blood circulation, nerve control and neurohumoral modulation of modern medicine. (ii) The needling, which can injure the tissue, is a noxious stimulation inducing pain. Acupuncture manipulation, such as lifting and thrusting, twisting and twirling, or electroacupuncture (EA) with the sufferable biggest intensity for patients should be a stronger pain stimulation. The needling sensation of soreness, numbness, distension and heaviness is a deep pain. (iii) There is an intrinsic analgesic system in brain, which centers around the periventricular and periaqueductal grey matter, contains endorphins as possible mediators, goes through the descending inhibition system in medulla oblon-gata, and acts on the gating mechanism in spinal cord. Itcould be producing analgesia while the system is activated. (iv) NRM might be a supraspinal center modulating pain, and the R-S neurons could展开更多
A new mixed-integrator-based bi-quad cell is proposed. An alternative synthesis mechanism of complex poles is proposed compared with source-follower-based bi-quad cells which is designed applying the positive feedback...A new mixed-integrator-based bi-quad cell is proposed. An alternative synthesis mechanism of complex poles is proposed compared with source-follower-based bi-quad cells which is designed applying the positive feedback technique. Using the negative feedback technique to combine different integrators, the proposed bi-quad cell synthesizes complex poles for designing a continuous time filter. It exhibits various advantages including compact topology, high gain, no parasitic pole, no CMFB circuit, and high capability. The fourth-order Butterworth lowpass filter using the proposed cells has been fabricated in 0.18μm CMOS technology. The active area occupied by the filter with test buffer is only 200 × 170 μm^2. The proposed filter consumes a low power of 201 μW and achieves a 68.5 dB dynamic range.展开更多
基金National Key R&D Program of China under Grant No.2018YFB1801603 and No.2017YFF0206201National Sci⁃ence and Technology Major Project under Grant 2017ZX03001024,NSFC under Grant No.61801259 and Beijing National Research Center for Infor⁃mation Science and Technology(BNRist).
文摘A robust digital predistortion(DPD)technique utilizing negative feedback iteration is introduced for linearizing power amplifiers(PAs)in long term evolution(LTE)/5G systems.Different from the conventional direct learning and indirect learning structure,the proposed DPD suggests a two-step method to identify the predistortion.Firstly,a negative feedback based iteration is used to estimate the optimal DPD signal.Then the corresponding DPD parameters are extracted by forward modeling with the input signal and optimal DPD signal.The iteration can be applied to both single-band and dual-band PAs,which will achieve superior linear performance than the conventional direct learning DPD while having a relatively low computational complexity.The measurement is carried out on a broadband Doherty PA(DPA)with a 200 MHz bandwidth LTE signal at 2.1 GHz,and on a 5G DPA with two 10 MHz LTE signals at 3.4/3.6 GHz for validation in dual-band scenarios.
文摘Waveform control method was commonly adopted to reduce the spatter of CO2 arc welding and improve the weld formation. It certainly would reduce the self-regulation ability of arc due to the adoption of segmented constant current control which especially led to arc" blowout with the abrupt change oat" arc" length or downward welding. Therefore alterative wire-feed system based on arc voltage negative feedback was put forward to improve the .stability of arc" length in this paper. Double closed-loop and double fuzzy P1 regulation were adopted in this system. Fuzzy control of induced voltage was adopted in the inner-loop which improved the stability and fast response of wire-feed system. Fuzz)" control of arc" voltage negative feedback was used in the outer-loop whose output .served as the input of negative feedback regulation of inner-loop induced voltage. This method could remain arc" length and weld penetration unchan, ged on the basils of reducing spatter and improving formation and it was proved by downward welding tests.
文摘One of the ingredients of the anthropogenic global warming hypothesis is the existence of large positive feedback in the climate system. An example is polar ice that, once melted, turns into blacker water that will increase radiation absorption and this rein-forces the melting. This causes a run-away scenario with a point of no return. Here it is shown that the polar ice can also have negative feedback aspects, where a melting of polar ice will cause it to reappear.
文摘Over the past three decades, neurophysiologists studying the neural circuitry responsible for control of skeletal muscles have developed several different general theories of sensorimotor control. These have usually invoked one or more of the sources of proprioceptive signals (e.g. muscle spindle and Golgi tendon organ afferents) in positive or negative feed-back loops to the homonymous alpha motoneurones. In this paper we consider to analyze the role of posi-tive feedback in combination of negative feedback due to important role of them in stabilizing the neu-romuscular system.
基金supported by the Natural Science Foundation of Zhejiang Province(No.Z1110937)
文摘The design and fabrication of an ultra-broadband power amplifier based on a GaN HEMT, which operates in the frequency range from 3 to 8 GHz, is presented in this paper. A TGF2023-02 GaN HEMT chip from Tri Quint is adopted and modeled. A novel negative feedback structure is applied in the circuit. The measured results show that the amplifier module has a wide range frequency response that is almost consistent with those of simulation at frequencies from 3 to 6.5 GHz. The measured power gain is greater than 7 dB between 3 and 6.5 GHz.The saturated output power is 38.5 dBm under DC bias of Vds =D28 V, Vgs D =-3:5 V at the frequency of 5.5 GHz.
文摘In this study, the temporal structure of the variation of North Atlantic Oscillation (NAO) and its impact on regional climate variability are analyzed using various datasets. The results show that blocking formations in the Atlantic region are sensitive to the phase of the NAO. Sixty-seven percent more winter blocking days are observed during the negative phase compared to the positive phase of the NAO. The average length of blocking during the negative phase is about 11 days, which is nearly twice as long as the 6-day length observed during the positive phase of the NAO. The NAO-related differences in blocking frequency and persistence are associated with changes in the distribution of the surface air temperature anomaly, which, to a large extent, is determined by the phase of the NAO. The distribution of regional cloud amount is also sensitive to the phase of the NAO. For the negative phase, the cloud amounts are significant, positive anomalies in the convective zone in the Tropics and much less cloudiness in the mid latitudes. But for the positive phase of the NAO, the cloud amount is much higher in the mid-latitude storm track region. In the whole Atlantic region, the cloud amount shows a decrease with the increase of surface air temperature. These results suggest that there may be a negative feedback between the cloud amount and the surface air t.emperature in the Atlantic region.
基金Supported by Research grants from the Japanese Ministry of Health,Labor and Welfare,No.H22-seishin-ippan-001the Japan Society for the Promotion of Science(JSPS) through a Grant-in-Aid for Scientific Research,No.22390225,No.25293250 and No.24591680+3 种基金Challenging Exploratory Research,No.23659565the Japanese Ministry of Education,Culture,Sports,Science and Technology(MEXT) through a Grant-in-Aid for Scientific Research on Innovative Areas(Comprehensive Brain Science Network),No.25129704Priority Areas-Research on the Pathomechanisms of Brain Disorders,No.18023045the Japan Foundation for Neuroscience and Mental Health
文摘AIM: To investigate executive function in Japanese adolescents and adults with autism spectrum disorders(ASD) compared to Japanese controls.METHODS: Thirty-three individuals with ASD and 33 controls participated. The ASD and control groups' demographic variables were matched for gender(male/female: 20/13 vs 20/13), age(26.1 ± 11.5 vs 26.8 ± 9.6), years of education(13.2 ± 2.9 vs 14.2 ± 1.9), full-scale intelligence quotient(IQ)(103.0 ± 16.7 vs 103.7 ± 14.7), performance IQ(96.2 ± 16.1 vs 97.8 ± 15.0), and verbal IQ(107.9 ± 16.3 vs 107.7 ± 14.4). Participants performed the Wisconsin Card Sorting Test(WCST), which assesses the executive processes involved in problem solving and cognitive flexibility, and the Continuous Performance Test(CPT), which assesses attention and impulsivity. Symptoms were assessed by the Autism-Spectrum Quotient Japanese version(AQ-J). First, we compared the scores of the WCST between the groups using a Mann-Whitney U-test and conducted an analysis of covariance for the variables with the scores of category archives and CPT scores as covariates. Second, we analyzed the correlation between the scores of the WCST and the AQ-J in the ASD group using Pearson's r.RESULTS: The total errors(TE) and the percentages of perseverative errors of the Milner type(%PEM) and Nelson type(%PEN) among the TE in the ASD group were significantly worse compared with the control group(ASD vs Control, respectively: TE: 16.0 ± 6.2 vs 12.6 ± 3.5, P = 0.012; %PEM: 11.7 ± 10.7 vs 6.6 ± 8.9, P = 0.037; %PEN: 20.1 ± 14.5 vs 8.7 ± 10.4, P = 0.0011). In contrast, no significant difference was observed between the two groups in the scores of categories achieved on the WCST or the CPT. An analysis of covariance revealed significant differences between the groups in the %PEN scores(P = 0.0062) but not in the TE or the %PEM scores. These results suggest that Japanese adolescents and adults with ASD have cognitive inflexibility. Furthermore, our results suggest that Japanese adolescents and adults with ASD may have difficulties using negative feedback because perseverative errors of the Nelson type indicate persistence in choosing the incorrect reaction. By contrast, there was no significant correlation between the WCST and AQ-J scores.CONCLUSION: We confirmed the presence of cognitive inflexibility in Japanese adolescents and adults with ASD. Our results also indicated that subjects with ASD may not use negative feedback effectively.
基金Sponsored by the National Natural Science Foundation of China(Grant No.41274183)the Science and Technology Department of Jilin Province(Grant No.20150520095JH)
文摘According to different applications,the performance parameters of the several Geo-Electromagnetic Magnetic Induction Sensors( GEMISs) which are the most representative in the world are compared. After discussing the several key technologies for improving the performance of GEMISs,the main conclusions are as follows: the application bandwidth can be expanded by adopting flux negative feedback( 1 m Hz-10 k Hz);"laminated"core structure is useful for suppressing eddy current loss; the effective permeability of the core has increased observably after adding flux concentrators to the two ends of the core; the chopper amplifier is a useful method to suppress 1/f noise for reducing the GEMIS's output noise; the indoor calibration scheme based on"long straight solenoid"proposed to obtain sensor sensitivity. Accordingly,the problem how to reduce the noise of GEMIS is urgent need to be solved,which will improve the performance of GEMIS. And there is plenty of work requires further study on parameters ' optimization of coil and core. In the future,miniaturization,intelligence and three-axis measurement are the development directions of GEMIS.
文摘It is considered three phases of development of a tropical cyclone: the origin, the steady-state regime and the termination, coinciding with three phases of self-oscillatory process: oscillation buid-up, dynamic balance and failure of self-oscillations. The rough size of energy of a cyclone, as column of air rotating with high speed, at initial and final stages of development and comparison of the received sizes with nuclear and hydrogen bombs is calculated. The model of the electronic oscillator with negative active conductivity by the numerical solution of the equation of the Van-der-Pol is analyzed. Formal coincidence of transient in this model with increase of capacity of vortical air formation, that allows to make mnemonic model of a cyclone in the form of volume self-oscillatory system is shown. The numerical solution of the made equations allows to construct schedules of dynamic process for each of particles of the investigated environment. The general recipe on restraint of development of a cyclone by compulsory entering into it of attenuation is given. Realization of this recipe by means of group of platforms with powerful wind-electrogenerator and the fans and uses of a principle of negative feedback is shown. The results of laboratory experiment confirming idea, taken as a principle struggle against an arising air whirlwind, by transformation of a laminar stream in chaotic, turbulent are resulted. For fuller check offered a wind-energetic method of struggle against a cyclone carrying out of more scale experiment is necessary.
文摘The design and performances of a high dynamic range DC-AC current sensor utilizing Giant Magneto-Impedance (GMI) are presented. The sensor is based on a GMI element with negative feedback. The sensing element is a 30 μm diameter GMI Co-based amorphous wire. It is curled to a toroidal core of 2 cm diameter. A bias magnetic field of about 650 A/m is applied to the GMI element to obtain an asymmetric GMI effect. A strong negative feedback is introduced to ensure linearity in a wide dynamic range. Analog conditioning electronics was fully developed. This includes a square wave oscillator based on an inverter trigger;a peak detector and a high gain amplifier with zero adjust. The GMI element is driven at a 3 MHz frequency and 5 mA peak-to-peak current. The closed-loop operations are investigated and the performances of the sensor are presented. DC current measurements are performed. The sensor exhibits good sensitivity and very good linearity, free from hysteresis, in a wide dynamic range of ±40 A. The sensitivity is about 0.24 V/A and the linearity error is about 0.02% of the full scale (FS). The hysteresis error is smaller than the measurement accuracy. AC current measurements using the developed sensor have also been successfully achieved. The sensor bandwidth in closed-loop was about 1.7 kHz.
文摘It is observed by in situ stain that LDH (1 5) ...nNAD + can probably enter the nucleopore and can be bound bound specifically with the genes that encode them. During the in vitro expression, the dilution of heart nuclear DNA fragments could enhance the expression activity of LDH/DNA and the amount of expressed LDH (1 5) is in proportion to the amount of dissociable LDH (1 5) on the LDH/DNA. With the integration of 14C Leu to the proteins, it is also observed that the addition of LDH (1 5) ...nNAD + can suppress the in vitro expression activity of LDH/DNA. AFM observation shows that the regulation sequence at the both ends of active genes may be bound with such active factors as proteins encoded by the genes which probably is the main molecular switch of gene expression and regulation we have been always searching for. Our work shows the prospective application of the combination of AFM and isotope labeling in the research of biological reaction.
基金We thank Prof.Qiang Cai(College of Life Sciences,Wuhan University)and Prof.Zheng Yuan(School of Life Sciences and Biotechnology,Shanghai Jiao Tong University)for providing morphology data for the eg1-1 and eg2-1D mutants.This work was supported by grants from the National Key R&D Program of China(2022YFD1200100)STI2030-Major Projects(2023ZD0406802)the National Natural Science Foundation of China(no.92035301 and no.31771765).
文摘Although both protein arginine methylation(PRMT)and jasmonate(JA)signaling are crucial for regulating plant development,the relationship between these processes in the control of spikelet development remains unclear.In this study,we used the CRISPR/Cas9 technology to generate two OsPRMT6a loss-of-function mutants that exhibit various abnormal spikelet structures.Interestingly,we found that OsPRMT6a can methylate arginine residues in JA signal repressors OsJAZ1 and OsJAZ7.We showed that arginine methylation of OsJAZ1 enhances the binding affinity of OsJAZ1 with the JA receptors OsCOI1a and OsCOI1b in the presence of JAs,thereby promoting the ubiquitination of OsJAZ1 by the SCF^(OsCOI1a/OsCOI1b) complex and degradation via the 26S proteasome.This process ultimately releases OsMYC2,a core transcriptional regulator in the JA signaling pathway,to activate or repress JA-responsive genes,thereby maintaining normal plant(spikelet)development.However,in the osprmt6a-1 mutant,reduced arginine methylation of OsJAZ1 impaires the interaction between OsJAZ1 and OsCOI1a/OsCOI1b in the presence of JAs.As a result,OsJAZ1 proteins become more stable,repressing JA responses,thus causing the formation of abnormal spikelet structures.Moreover,we discovered that JA signaling reduces the OsPRMT6a mRNA level in an OsMYC2-dependent manner,thereby establishing a negative feedback loop to balance JA signaling.We further found that OsPRMT6a-mediated arginine methylation of OsJAZ1 likely serves as a switch to tune JA signaling to maintain normal spikelet development under harsh environmental conditions such as high temperatures.Collectively,our study establishes a direct molecular link between arginine methylation and JA signaling in rice.
文摘Phytohormone ethylene plays pivotal roles in plant response to developmental and environmental signals. During the past few years, the emerging evidence has led us to a new understanding of the signaling mechanisms and regulatory networks of the ethylene action. In this review, we focus on the major advances made in the past three years, particularly the findings leading to new paradigms and the observations under debate. With the recent demonstration of the regulation of the protein stability of numerous key signaling components including EIN3, ELL1, EIN2, ETR2, EBFI/EBF2, and ETPI/ETP2, we highlight proteasome-dependent protein degradation as an essential regulatory mechanism that is widely adopted in the ethylene signaling pathway. We also discuss the implication of the negative feedback mechanism in the ethylene signaling pathway in light of ethylene-induced ETR2 and EBF2 gene expression. Meanwhile, we summarize the controversy on the involvement of MKK9-MPK3/6 cascade in the ethylene signaling versus biosynthesis pathway, and discuss the possible role of this MAPK module in the ethylene action. Finally, we describe the complex interactions between ethylene and other signaling pathways including auxin, light, and plant innate immunity, and propose that EIN3/ EIL1 act as a convergence point in the ethylene-initiated signaling network.
基金the National Key Research and Development Program of China(2016YFA0500503)the National Natural Science Foundation of China(31730066 and 31230050)+1 种基金the Ministry of Agriculture of the People's Public of China(2018ZX0800919B and 2014ZX0800929B)Huazhong Agricultural University Scientific&Technological Selfinnovation Foundation(2015RC014).
文摘Symbiotic root nodules are root lateral organs of plants in which nitrogen-fixing bacteria(rhizobia)convert atmospheric nitrogen to ammonia.The formation and number of nodules in legumes are precisely controlled by a rhizobia-induced signal cascade and host-controlled autoregulation of nodulation(AON).However,how these pathways are integrated and their underlying mechanisms are unclear.Here,we report that microRNA172c(miR172c)activates soybean(Glycine max)R hizobia-induced CLE1(GmRICI)and GmRIC2 by removing the transcriptional repression of these genes by Nodule Number Control 1(NNC1),leading to the activation of the AON pathway.NNC1 interacts with GmNINa,the soybean ortholog of Lotus NODULE INCEPTION(NIN),and hampers its transcriptional activation o i G m RICI and GmRIC2.Importantly,GmNINa acts as a transcriptional activator of miR172c.Intriguingly,NNC1 can transcriptionally repress miR172c expression,adding a negative feedback loop into the NNC1 regulatory network.Moreover,GmNINa interacts with NNC1 and can relieve the NNC1-mediated repression of miR172c transcription.Thus,the GmNINa-miR172c-NNC1 network is a master switch that coordinately regulates and optimizes NF and AON signaling,supporting the balance between nodulation and AON in soybean.
基金This work was supported by grants from National Natural Science Foundation of China (No. 30971312) and the Key Project of Beijing Municipal Education Commission Sci-Tech Development Program (No. KZ201110025028).
文摘apamvcin was first isolated from a strain of Sreptomyces hygroscopicus in the early 1970s froma soil sample taken on Easter Island. Because the antiproliferative effects of rapamycin on yeast cell, as well as B and T lymphocytes, it was first identified as an antimicrobial agent with potent immunosuppressive activity and has been used in antirejection therapy.
基金This work was partly supported by the National Science Foundation.
文摘Hippo signaling plays a crucial role in growth control and tumor suppression by regulating cell proliferation,apoptosis,and differentiation.How Hippo signaling is regulated has been under extensive investigation.Over the past three years,an increasing amount of data have supported a model of actin cytoskeleton blocking Hippo signaling activity to allow nuclear accumulation of a downstream effector,Yki/Yap/Taz.On the other hand,Hippo signaling negatively regulates actin cytoskeleton organization.This review p rovides insight on the mutual regulatory mechanisms between Hippo signaling and actin cytoskeleton for a tight control of cell behaviors during animal development,and points out outstanding questions for further investigations.
基金supported by the National Natural Science Foundation of China (60976029)
文摘A fully integrated 40 Gbit/s optical receiver analog front-end (AFE) including a transimpedance amplifier (TIA) and a limiting amplifier (LA) for short distance communication is described in this paper. The proposed TIA employs a modified regulated cascode (RGC) configuration as input stage, and adopts a third order interleaving active feedback gain stage. The LA utilizes nested active feedback, negative capacitance, and inductor peaking technology to achieve high voltage gain and wide bandwidth. The tiny photo current received by the receiver AFE is amplified to a single-ended voltage swing of 200 mV(p-p). Simulation results show that the receiver AFE provides conversion gain of up to 83 dBΩ and bandwidth of 34.7 GHz, and the equivalent input noise current integrated from 1 MHz to 30 GHz is about 6.6 μA(rms).
文摘(i) The structure and function of the meridian (channel and collateral) described by ancient medical doctors may correspond to the blood circulation, nerve control and neurohumoral modulation of modern medicine. (ii) The needling, which can injure the tissue, is a noxious stimulation inducing pain. Acupuncture manipulation, such as lifting and thrusting, twisting and twirling, or electroacupuncture (EA) with the sufferable biggest intensity for patients should be a stronger pain stimulation. The needling sensation of soreness, numbness, distension and heaviness is a deep pain. (iii) There is an intrinsic analgesic system in brain, which centers around the periventricular and periaqueductal grey matter, contains endorphins as possible mediators, goes through the descending inhibition system in medulla oblon-gata, and acts on the gating mechanism in spinal cord. Itcould be producing analgesia while the system is activated. (iv) NRM might be a supraspinal center modulating pain, and the R-S neurons could
文摘A new mixed-integrator-based bi-quad cell is proposed. An alternative synthesis mechanism of complex poles is proposed compared with source-follower-based bi-quad cells which is designed applying the positive feedback technique. Using the negative feedback technique to combine different integrators, the proposed bi-quad cell synthesizes complex poles for designing a continuous time filter. It exhibits various advantages including compact topology, high gain, no parasitic pole, no CMFB circuit, and high capability. The fourth-order Butterworth lowpass filter using the proposed cells has been fabricated in 0.18μm CMOS technology. The active area occupied by the filter with test buffer is only 200 × 170 μm^2. The proposed filter consumes a low power of 201 μW and achieves a 68.5 dB dynamic range.