Behavioral impulse and time pressure jointly influence intentional inhibition: evidence from the Free Two-Choice Oddball task.

Intentional inhibition is a crucial component of self-regulation, yet it is under-researched, because it is difficult to study without external stimuli or overt behaviors. Although Free-Choice tasks have been developed, it remains unclear how two key design features (i.e., behavioral impulse and time pressure) affect their sensitivity to intentional inhibition. To investigate this, the present study developed a Free Two-Choice Oddball task, which generated both an inhibition rate index and a response time (RT) index. Two experiments were conducted to systematically manipulate the ratio of the reactive standard to oddball trials and reaction time limit, inducing diverse behavioral impulses and different time pressures. The following findings were obtained from the critical Free-Choice trials. In the equal ratio condition, participants demonstrated comparable RTs for both the standard and oddball responses. In the moderate-ratio condition, participants exhibited longer RTs for the oddball than standard responses under low- but not high-time pressure. In the high-ratio condition, while RTs for the oddball responses were longer than those for the standard responses under both the high- and low-time pressures, participants displayed a decreased inhibition rate under the high-time pressure compared to the low-time pressure. Finally, participants exhibited a reduced inhibition rate in the high-ratio condition compared to the moderate-ratio condition. Together, these findings suggest that Free-Choice tasks can reflect intentional inhibition under specific conditions, and intentional inhibition is susceptible to both behavioral impulse and time pressure, while also establishing the theoretical and methodological foundations for subsequent research.

Resting respiratory sinus arrhythmia moderates the within-person relations of parental emotional expressivity and children's prosocial behaviors.

Parental supportive emotional expressivity could contribute to children's prosocial behaviors, and such an effect may differ for children with different levels of resting respiratory sinus arrhythmia (RSA). This study disentangled the stable differences across dyads (i.e., between-person effects) from the dynamic associations between parental expressivity and children's prosocial behaviors within dyads (i.e., within-person effects) and determined how resting RSA functioned as a susceptibility factor in such effects. The longitudinal design consisted of three measurements with a 1-year interval performed among 208 school-aged children (48.6% girls; Han nationality) and their parents (153 mothers and 55 fathers). The initial measurement was conducted when the children were 7 years old (Mage  = 7.13, SDage  = .33). Resting RSA was calculated at the first measurement; parents reported children's prosocial behaviors and parental expressivity at each of the three measurements. The results demonstrated significant between- and within-person effects of parental expressivity on children's prosocial behaviors and found a moderating role of children's resting RSA in the within-person effects. These findings suggest that children displayed more prosocial behaviors when parents showed more supportive expressivity both across and within dyads, and higher resting RSA operated as a differential susceptibility factor in the intraindividual fluctuations in parental expressivity.

Aggressive behaviors predict greater intraindividual reaction time variability in children: Evidence from cross-lagged panel models.

Deficits in attentional control or inhibitory control are distinct features of childhood aggressive behaviors. Lower attentional control or inhibitory control is considered to predict more aggressive behaviors, while few studies have documented the possible predictive effects of aggressive behaviors on attentional control or inhibitory control. The present study examined the bidirectional relations between aggressive behaviors and both inhibitory control and attentional control in 169 Chinese primary school children (75 girls, Mage = 7.15, SDage = 0.33), annually for 3 years starting at age 7. The No-go accuracy on a Go/No-go task was used as the index of inhibitory control, and the intraindividual reaction time variability (IIRTV) of correct Go trials indicated attentional control. The aggressive behaviors subscale of the child behavior checklist-Chinese version was used to assess the children's aggressive behaviors. The results demonstrated a significant and stable predictive effect of previous aggressive behaviors on subsequent attentional control, with more aggressive behaviors predicting greater IIRTV at both the between-child and within-child levels. No significant effects of inhibitory control or attentional control on aggressive behaviors or sex-specific patterns were found. The findings suggest the negative impact of childhood aggressive behaviors on attentional control and underscore the importance of early prevention and intervention for childhood aggressive behaviors.

Different adverse childhood experiences and adolescents' altruism: The mediating role of life history strategy.

INTRODUCTION: The present study sought to investigate whether the relationship between childhood trauma, childhood socioeconomic (SES), and adolescents' altruism were mediated by their life history strategies and different adverse childhood experiences may function diversely on altruism, with two waves of data collected 6 months apart in a longitudinal design among Chinese adolescents. METHODS: A total of 658 adolescents (Mage = 13.51, SD = 0.73 at T1) were recruited and completed the online survey; their life history strategies were measured by the Mini-K, the Delayed of Gratification Questionnaire (DOG), and the Chinese version of the Adolescent Risk-Taking Questionnaire (ARQ-RB) together, and their altruism was collected again after six months. RESULTS: After controlling for gender and their altruism at T1, the results showed that childhood trauma (i.e., emotional maltreatment, physical maltreatment), as well as low SES and fast life history strategy, were significantly negatively correlated with adolescents' altruism at T2. Importantly, life history strategy at T1 mediated the relationship between T1 emotional maltreatment, T1 low SES, and adolescents' altruism at T2. However, the effect of physical maltreatment on altruism was not mediated by life history strategy. CONCLUSIONS: This study indicated that emotional maltreatment and low SES can affect adolescents' altruism by influencing the formation of adolescents' life history strategies. The findings revealed the different influences of adverse childhood experiences on adolescents' altruism, which supplied new empirical evidence for the life history theory and provided certain reference values for cultivating adolescents' altruism.

Effects of Helicopter Parenting, Tiger Parenting and Inhibitory Control on the Development of Children's Anxiety and Depressive Symptoms.

Helicopter parenting and tiger parenting may increase the risks of anxiety and depression in children. However, it is unclear how these parenting styles affect the developmental outcomes and trajectories of anxiety and depressive symptoms, and how children's internal inhibitory control (IC) moderates such effects. The present study aimed to examine this issue. A sample of 172 typically developing children (77 girls; Mage = 7.14, SDage = 0.33) and their parents participated in the study. Parents reported children's anxiety and depressive symptoms using the Child Behavior Checklist each year from the first measurement (T1) to the third measurement (T3) and reported their helicopter parenting and tiger parenting at T1. Children completed the Go/No-go task at T1 to measure their IC. Higher T1 helicopter parenting impeded the declines in anxiety and depression over time, and higher T1 tiger parenting predicted more anxiety and depressive symptoms at T3. However, such effects were only observed in children with low IC, and higher IC buffered the adverse impacts of both helicopter parenting and tiger parenting on children's anxiety and depressive symptoms. These findings revealed that helicopter parenting and tiger parenting had negative impacts on the developmental trajectories and outcomes of anxiety and depression in children and suggest that IC plays an important role in alleviating the risks of anxiety and depression among children in adverse environments.

Parent-Child Discrepancies in Perceived Parental Control and Their Associations with Children's Prosocial Behaviors in Early Adolescence within Chinese Families.

How parent-child discrepancies in perceived parental control associate with children's prosocial behaviors remains unknown. This study examined this issue in 578 Chinese children (297 girls, Mage = 10.85, SDage = 0.72) and their mothers and fathers. Parents and children reported parental psychological and behavioral control, and children reported their prosocial behaviors. The latent difference scores modeling showed that compared to parents' perceptions, children's higher perceptions of guilt induction were related to more public prosocial behaviors; higher perceptions of love withdrawal were linked to fewer altruistic, compliant, emotional, and dire prosocial behaviors; and higher reporting of solicitation was associated with more general prosocial behaviors. The findings revealed the association between parent-child discrepancies and early adolescents' prosocial behaviors, supporting both the discrepancy-maladaptive hypotheses and the discrepancy-adaptive hypotheses within Chinese families.

Childhood trauma, intraindividual reaction time variability, baseline respiratory sinus arrhythmia, and perceived relapse tendency among males with substance use disorders.

Background: People with substance use disorders (SUDs) who have experienced serious childhood trauma may have executive function impairments contributing to relapse. Baseline respiratory sinus arrhythmia (RSA) reflects physiological regulation capacity, which has been found to buffer the negative effects of childhood trauma. Baseline RSA has also been found to be related to intraindividual reaction time variability (IIRTV), which is an index of executive function.Objectives: The present study examined the relationship between childhood trauma and perceived relapse tendency, the mediation role of IIRTV, and the moderation role of baseline RSA.Methods: The study is cross-sectional, a total of 110 males with SUDs participated (Mage = 46.45 years, SD = 11.24). The Childhood Trauma Questionnaire and Intention to Rehabilitate Questionnaire were used to assess childhood trauma and perceived relapse tendency, the two-choice oddball task was used to measure IIRTV, and electrocardiogram (ECG) data were collected to obtain baseline RSA.Results: IIRTV mediated the relationship between childhood trauma and perceived relapse tendency (Coeff = 0.049, Boot CI [0.004, 0.121]); interaction of childhood trauma and Baseline RSA negatively influences IIRTV (ß = -0.208, t = -2.022, p = .046).Conclusion: The results suggest that males with SUDs who have experienced serious childhood trauma may have executive function impairments that contribute to relapse, and baseline RSA may buffer the negative effect of childhood trauma on IIRTV. These findings suggest that the prevention of relapse through cognitive enhancement can be complemented by the enhancement of physiological regulation.

Insights into the conversion of dissolved organic phosphorus favors algal bloom, arsenate biotransformation and microcystins release of Microcystis aeruginosa.

Little information is available on influences of the conversion of dissolved organic phosphorus (DOP) to inorganic phosphorus (IP) on algal growth and subsequent behaviors of arsenate (As(V)) in Microcystis aeruginosa (M. aeruginosa). In this study, the influences factors on the conversion of three typical DOP types including adenosine-5-triphosphate disodium salt (ATP), ß-glycerophosphate sodium (ßP) and D-glucose-6-phosphate disodium salt (GP) were investigated under different extracellular polymeric secretions (EPS) ratios from M. aeruginosa, and As(V) levels. Thus, algal growth, As(V) biotransformation and microcystins (MCs) release of M. aeruginosa were explored in the different converted DOP conditions compared with IP. Results showed that the three DOP to IP without EPS addition became in favor of algal growth during their conversion. Compared with IP, M. aeruginosa growth was thus facilitated in the three converted DOP conditions, subsequently resulting in potential algal bloom particularly at arsenic (As) contaminated water environment. Additionally, DOP after conversion could inhibit As accumulation in M. aeruginosa, thus intracellular As accumulation was lower in the converted DOP conditions than that in IP condition. As(V) biotransformation and MCs release in M. aeruginosa was impacted by different converted DOP with their different types. Specifically, DMA concentrations in media and As(III) ratios in algal cells were promoted in converted ßP condition, indicating that the observed dissolved organic compositions from ßP conversion could enhance As(V) reduction in M. aeruginosa and then accelerate DMA release. The obtained findings can provide better understanding of cyanobacteria blooms and As biotransformation in different DOP as the main phosphorus source.

Real-time dynamics of noise-like vector pulses in a figure-eight fiber laser.

The vector nature of noise-like pulses (NLPs) in a figure-eight erbium-doped fiber laser based on the nonlinear amplifier loop mirror (NALM) configuration is experimentally investigated. After achieving the operation regime of NLPs, both the group velocity locked noise-like vector pulses (GVL-NLVPs) and the polarization locked noise-like vector pulses (PL-NLVPs) are observed in the cavity. By virtue of the dispersive Fourier transform (DFT) technique, their spectral evolution and the energy vibration are measured and analyzed in real time. We also obtain another state of noise-like vector pulses (NLVPs) with combined characteristics of GVL-NLVPs and PL-NLVPs. It is shown that the NLVPs are sensitive to the cavity birefringence. Our results would be beneficial to complement the understanding of vector dynamics of NLPs in ultrafast fiber lasers.

Graphene-enhanced polarization-insensitive all-optical wavelength conversion based on four-wave mixing.

All-optical wavelength conversion technology based on four-wave mixing (FWM) effect is a promising development need of the modern high-speed optical signal processing system. In this work, we report on the polarization insensitive four-wave mixing based on graphene for all optical wavelength conversion. To overcome the polarization sensitivity of FWM, a dual-pump configuration was proposed based on the combination of graphene and the optical fibers. Our experimental results illustrate that by using the dual pump configuration, the FWM-based wavelength conversion efficiency, can be enhanced by graphene with about 8 dB when the state of polarization of the two pumps are parallel. This proposed all-optical wavelength converter based on graphene may provide a new approach for the next generation optical communications and signal processing.

Gonadotropin-releasing hormone agonist for the preservation of ovarian function in survivors of haematopoietic stem cell transplantation for haematological diseases.

OBJECTIVE: Administration of GnRH agonist (GnRHa) prior to chemotherapy may decreases the risk of gonadal dysfunction in patients with tumors. However, relevant data in haematopoietic stem cell transplantation (HSCT) recipients has not yet been established. Hence, the present study was designed to evaluate the clinical efficacy of GnRHa cotreatment prior to myeloablative regimens on ovarian protection in female survivors of HSCT for haematological diseases. PATIENTS AND METHODS: Eligible patients were divided into a GnRHa group and a control group. Medical records regarding age at HSCT; diagnosis/indication for HSCT; pre- and posttransplantation serum sex hormone levels; menstruation and perimenopausal symptoms after HSCT were collected and compared. The primary and secondary outcome was the incidence of premature ovarian insufficiency (POI) symptoms associated with hypoestrogenism. RESULTS: A total of 330 patients were enrolled in the study: 19 patients were lost to follow-up, and clinical information was obtained in 311 patients. There was no significant difference in the primary outcome of follow-up between the two groups (78.50% [84 of 107] for the GnRHa group versus 83.33% [170 of 204] for the control group). The adjusted relative risks (RR) and 95% confidence interval (CI) were 1.19 and 0.73-1.93 (P = 0.487). Among patients who received cotreatment with GnRHa, 62.62% (67 of 107) complained of perimenopausal symptoms, which was significantly lower than the 74.51% (152 of 204) in the control group (adjusted RR: 1.46, 95% CI: 1.04-2.06, P = 0.031). CONCLUSION: GnRHa cotreatment may not decrease the POI rate in HSCT survivors. However, it may reduce perimenopausal symptoms in this population, suggesting a potential benefit of GnRHa in clinical practice and warrant further researches.

Responses of nickel bioavailability and toxicity of Prorocentrum Donghaienses to dissolved organic matter (DOM) fractions incubated in urea.

Urea, nickel (Ni) and dissolved organic matter (DOM) from land varied with different sources have a great impact on the offshore ecosystem. The heterogeneity of Ni bioavailability and toxicity of Prorocentrum donghaiense influenced by DOM fractions incubated in urea was investigated in this study. On the occasion, chlorophyll (Chl a) concentration, growth rate, and photosynthesis parameters were monitored to track changes occurring in the test organism. Chl a concentration and photosynthesis parameters in the treatment of hydrophilic DOM (HPI) with Ni-free was significantly higher than that in the control treatment, and similar data were shown in the treatment of hydrophobic DOM（HPO）with the low Ni environment (0.17µmol L-1). However, the opposite phenomena were observed in the treatments of HPO with the higher Ni environment (over 170µmol L-1). Moreover, the EC50 of Ni for P.donghaiense incubated in HPO was relatively lower than that in HPI and control treatment, which implied that HPO elevated the toxicity of Ni. Therefore, the varied DOM compositions because of different origins, as a chelating agent and potential nutrient source in coastal waters, shows the significantly different bioavailability and toxicity of Ni with the increasing inputs of urea, which in turn influences the dynamics of phytoplankton.

The Effect of CRHBP rs10062367 Polymorphism and Parenting Styles on Internalizing Problems in Preschoolers: The Moderating Effect of Sensory Processing Sensitivity.

The present study aimed to examine how CRHBP rs10062367 polymorphism interacted with parenting styles and sensory processing sensitivity (SPS) to impact on preschoolers' internalizing problems. A total of 446 preschoolers (Mage = 4.55, SD = 1.07) participated in the study and their saliva were extracted to genotype the CRHBP rs10062367 polymorphism, and their parents were invited to complete a battery of questionnaires to assess parenting styles, preschoolers' SPS, and internalizing problems. Results indicated that high SPS preschoolers with A allele exhibited fewer internalizing problems under the condition of positive parenting while they exhibited more internalizing problems under the condition of negative parenting. The findings provide support for the Differential Susceptibility Model/Biological Sensitivity to Context Theory that A allele of rs10062367 and high SPS might be the "susceptibility markers" of children to environments.

Six1 Promotes Epithelial-Mesenchymal Transition in Bronchial Epithelial Cells via the TGFß1/Smad Signalling Pathway.

INTRODUCTION: The homeodomain transcription factor sine oculis homeobox homolog 1 (Six1) plays a crucial role in embryogenesis and is not expressed in normal adult tissue but is expressed in many pathological processes, including airway remodelling in asthma. The current study aimed to reveal the effects of Six1 in regulating the airway remodelling and its possible mechanism. METHODS: A mouse model of ovalbumin-induced asthma-associated airway wall remodelling and a bronchial epithelial cell (16HBE) model of transforming growth factor ß1 (TGFß1)-induced epithelial-mesenchymal transition (EMT) were used to investigate the role of Six1. Then, 16HBE cells were transformed with Six1 expression vectors and treated with a TGFß1 pathway inhibitor to determine the role of Six1 in EMT. The effect of Six1 and its possible mechanism were assessed by immunohistochemistry, RT-PCR, and Western blot. RESULTS: Six1 expression was elevated in the lungs in an OVA mouse model of allergic asthma and in 16HBE cells treated with TGFß1. Six1 overexpression promoted an EMT-like phenotype with a decreased protein expression of E-cadherin and increased protein expression of α-smooth muscle actin (α-SMA) as well as fibronectin in 16HBE cells; these effects appeared to promote TGFß1 and phospho-Smad2 (pSmad2) production, which are the main products of the TGFß1/Smad signalling pathway, which could be reduced by a TGFß1 inhibitor. CONCLUSION: These data reveal that Six1 and TGFß1 are potentially a part of an autocrine feedback loop that induces EMT, and these factors can be reduced by blocking the TGFß1/Smad signalling pathway. As such, these factors may represent a promising novel therapeutic target for airway remodelling in asthma.

Intraindividual reaction time variability as an index of attentional control acts as a moderator of the longitudinal relationships between marital quality and children's externalizing problems.

The current study investigated whether trial-to-trial intraindividual reaction time variability (IIRTV), which serves as an index of attentional control fluctuations, moderates the effect of marital quality at 7 years of age on the development of children's externalizing problems from 7 to 9 years of age (N = 197). At the first assessment (T1), a flanker task was administered to children for assessing their IIRTV. The Chinese version of a marital quality questionnaire (Evaluating and Nurturing Relationship Issues, Communication, and Happiness [ENRICH]) and the Chinese version of the Child Behavior Checklist (CBCL) were completed by children's mothers to assess marital quality and children's externalizing problems. At the second and third assessments (T2 and T3), children's externalizing problems were reassessed by their mothers. Growth curve analyses showed that boys' externalizing problems were relatively high and significantly decreased over time, whereas girls' externalizing problems were relatively low and stable. Importantly, the results indicated that boys' IIRTV (but not girls' IIRTV) and parental marital quality interactively predict the concurrent and developmental trajectories of externalizing problems. Specifically, boys with greater IIRTV were found to exhibit a relatively persistent high level of externalizing problems in the context of poor parental marital quality, whereas boys with lower IIRTV were found to exhibit a relatively low level of externalizing problems over time regardless of their parental marital quality. The findings suggest that poorer attentional control indexed by greater IIRTV is a robust predictor of boys' externalizing problems and that better attentional control indexed by lower IIRTV may buffer the negative impact of adverse family environment on the development of boys' externalizing problems.

Dexmedetomidine maintains blood-brain barrier integrity by inhibiting Drp1-related endothelial mitochondrial dysfunction in ischemic stroke.

Stroke is the second leading cause of death and long-term disability worldwide, which lacks effective treatment. Perioperative stroke is associated with much higher rates of mortality and disability. The neuroprotective role of dexmedetomidine (Dex), a highly selective agonist of alpha2-adrenergic receptor, has been reported in a stroke rat model, and it was found that pretreatment of Dex before stroke could alleviate blood-brain barrier (BBB) breakdown. However, the underlying mechanisms are still unknown. As the brain endothelial cells are the main constituents of BBB and in high demand of energy, mitochondrial function of endothelial cells plays an important role in the maintenance of BBB. Given that dynamin-related protein 1 (Drp1) is a protein mediating mitochondrial fission, with mitochondrial fusion that balances mitochondrial morphology and ensures mitochondria function, the present study was designed to investigate the possible role of Drp1 in endothelial cells involved in the neuroprotective effects of Dex in ischemic stroke. Our results showed that preconditioning with Dex reduced infarction volume, alleviated brain water content and BBB damage, and improved neurological scores in middle cerebral artery occlusion rats. Meanwhile, Dex enhanced cell activity and decreased cell apoptosis in oxygen-glucose deprivation human brain microvascular endothelial cells in vitro. These protective effects of Dex were correlated with the mitochondrial morphology integrality of endothelial cells, mediated by increased phosphorylation of serine 637 in Drp1, and could be reversed by α2-adrenergic receptor antagonist Yohimbine and AMP-activated protein kinase inhibitor Compound C. These findings suggest new molecular pathways involved in the neuroprotective effects of Dex in ischemic stroke. As Dex is routinely used as a sedative drug clinically, our findings provide molecular evidence that it has perioperative neuroprotection from ischemic stroke.

The COMT rs4680 polymorphism, family functioning and preschoolers' attentional control indexed by intraindividual reaction time variability.

Trial-to-trial intraindividual reaction time variability (IIRTV) serves as an index of attentional control and related endogenous brain function. What determinants contribute to preschoolers' attentional control indexed by IIRTV remains unknown. The present study examined how catechol-o-methyltransferase (COMT) rs4680 polymorphism interacted with family functioning (cohesion and adaptability) to impact on preschoolers' attentional control indexed by IIRTV. One hundred forty-four preschool children (Mage  = 4.19, SD = 0.63) completed the flanker task to assess their IIRTV. Their parents were asked to fill out the Family Adaptability and Cohesion Evaluation Scale II to assess family functioning. After controlling for age, socioeconomic status (SES) and mean reaction time, results showed that the COMT rs4680 polymorphism was positively associated with preschoolers' IIRTV at the 5% significance level (p = .02) but not after multiple testing adjustment (p = .08). Moreover the COMT rs4680 polymorphism significantly interacted with family functioning to impact on preschoolers' IIRTV and the interaction effects remained significant after correction for multiple testing (p = .01, ΔR2  = 0.06 in congruent conditions; p = .04, ΔR2  = 0.04 in combined conditions). In addition, the significant interaction between SES and COMT rs4680 polymorphism was also found in the present study (p = .01, ΔR2  = 0.05 in congruent conditions; p = .05, ΔR2  = 0.03 in combined conditions). No sex differences were found in the present sample. The findings of the present study expand our knowledge about the gene × environment underpinnings of children's attentional control and endogenous brain function, and provide evidence for the Vantage Sensitivity model on children's development.

Dynamic behaviors of multiple-soliton pulsation in an L-band passively mode-locked fiber laser with anomalous dispersion.

As a universal phenomenon in nonlinear optical systems, the soliton pulsating behavior is useful to achieve high pulse energy and can further enrich the complex soliton dynamics. To the best of our knowledge, herein we have demonstrated the observation of multiple-soliton pulsations in an L-band mode-locked fiber laser based on a nonlinear amplifying loop mirror with anomalous dispersion for the first time. Based on the dispersive Fourier transform method, we find that the pulsations in the multi-soliton regime are accompanied with the pulse width breathing and spectrum oscillation. In addition, the corresponding number of pulsating solitons increases linearly from 8 to 16 with the pump power. Our findings can facilitate a better understanding of the complex mechanism of soliton pulsations.

Perceived stress of the COVID-19 pandemic and adolescents' depression symptoms: The moderating role of character strengths.

The outbreak of COVID-19 could increase adolescents' psychological distress and have a detrimental effect on their mental health. However, the negative effect of the COVID-19 pandemic on adolescents' mental health might be moderated by their existing psychological resources. The present study sought to investigate whether the relationship between adolescents' perceived stress of the COVID-19 pandemic and their depression symptoms was alleviated by their character strengths. A total of 617 adolescents were recruited and completed the online survey during the COVID-19 pandemic. The results indicated that adolescents' perceived stress of the COVID-19 pandemic was significantly positively correlated with their depression symptoms. Character strengths were significantly negatively correlated with adolescents' perceived stress of the COVID-19 pandemic and their depression symptoms. Moreover, the moderating effect of character strengths on the relationship between adolescents' perceived stress of the COVID-19 pandemic and their depression symptoms was significant. Therefore, adolescents' character strengths as a protective factor could buffer the effect of perceived stress of the COVID-19 pandemic on their depression symptoms and contribute to maintaining their mental health.

Simultaneous generation and real-time observation of loosely bound solitons and noise-like pulses in a dispersion-managed fiber laser with net-normal dispersion.

We demonstrate the coexisting dynamics of loosely bound solitons and noise-like pulses (NLPs) in a passively mode-locked fiber laser with net-normal dispersion. The total pulse number of the single soliton bunch under the NLP operation regime almost increases linearly with increasing pump power, whereas the average pulse spacing decreases accordingly. Furthermore, pulse-to-pulse separation between adjacent soliton pulses in one soliton bunch keeps in the range of hundreds of picoseconds, which decreases from left to right with the change of time. Besides, the real-time observation has been performed by utilizing the time-stretch method, showing that each one of the loosely bound solitons on the NLP operation is actually composed of chaotic wave packets with random intensities. These findings obtained will facilitate the in-depth understanding of nonlinear pulse behaviors in ultrafast optics.