Traveling waves and spreading properties for a reaction-diffusion competition model with seasonal succession*

In this paper, we investigate the propagation dynamics of a reaction–diffusion competition model with seasonal succession in the whole space. Under the weak competition condition, the corresponding kinetic system admits a globally stable positive periodic solution ( u ^ ( t ) , v ^ ( t ) ) . By the method of upper and lower solutions and the Schauder fixed point theorem, we first obtain the existence and nonexistence of traveling wave solutions connecting (0, 0) to ( u ^ ( t ) , v ^ ( t ) ) . Then we use the comparison arguments to establish the spreading properties for a large class of solutions.

Lexical Competition Effects in Aphasia

<p>Some aphasic patients show single word production deficits in some situations where object naming is required (e.g., they perform well when objects are presented in unrelated groups (e.g., Cat, Fork, Bread...), but deteriorate when the same items are presented in semantically related groups (e.g., Cat, Cow, Dog...)) (see Wilshire & McCarthy, 2002). We investigated whether context-sensitive single-word production impairments reflect an impaired ability to resolve lexical competition. Three groups of participants (non-fluent aphasics, fluent aphasics, and older controls) completed four tasks that manipulated lexical competition: 1) A category exemplar task, where a high competition condition involved generating items from broad categories (e.g., Animals: "Cat. Dog" etc.), and a low competition condition involved generating items from narrow categories (e.g., Pets: Cat. Dog" etc); 2) A verb generation task, where participants were presented with objects and were required to generate related verbs. The high competition objects were related to a range of verbs (e.g., Penny: Spend"/"Pay"/"Buy" etc), and the low competition objects were related to one dominant verb (e.g., Scissors: "Cut"); 3) A name agreement task where a high competition condition involved naming low name agreement objects (e.g., Artist/Painter), and a low competition condition involved naming of high name agreement objects (e.g., Anchor), and; 4) A sentence completion task, where extrinsic competition was introduced via presentation of auditory distracters. The low competition distracters did not make sense (e.g., Barry wisely chose to pay the RANGE: "Bill"/"Cashier" etc), whereas the high competition distracters did (e.g., Barry wisely chose to pay the FINE: "Bill"/Cashier" etc). Our first hypothesis was that all participants would show high competition costs in increased response latencies and/or decreased accuracy. At the group level, this hypothesis was supported in all four tasks. At the individual level, there was mixed support as some participants showed predicted effects on the verb generation, name agreement, and sentence completion tasks. The second hypothesis was that exaggerated competition costs would occur in some or all non-fluent aphasics. At the group level this hypothesis was not clearly supported on any task. At the individual level there was mixed support, with some indications that non-fluents may be more likely to show significant competition effects than fluents. The third hypothesis was that non-fluent aphasics with relatively well preserved single word production but relatively impaired sentence production may be most likely to show exaggerated lexical competition effects. There was little support for this hypothesis. It was concluded that the data do not support the hypothesis that context-sensitive single-word production impairments are symptomatic of an impaired ability to resolve lexical competition. However, we have gained information on how heterogeneous aphasics perform on tasks that manipulate lexical competition, and we have gained some insights that may direct future research down a path towards more informative results, and increased knowledge on the complex process of speech production.</p>

Lexical Competition Effects in Aphasia

<p>Some aphasic patients show single word production deficits in some situations where object naming is required (e.g., they perform well when objects are presented in unrelated groups (e.g., Cat, Fork, Bread...), but deteriorate when the same items are presented in semantically related groups (e.g., Cat, Cow, Dog...)) (see Wilshire & McCarthy, 2002). We investigated whether context-sensitive single-word production impairments reflect an impaired ability to resolve lexical competition. Three groups of participants (non-fluent aphasics, fluent aphasics, and older controls) completed four tasks that manipulated lexical competition: 1) A category exemplar task, where a high competition condition involved generating items from broad categories (e.g., Animals: "Cat. Dog" etc.), and a low competition condition involved generating items from narrow categories (e.g., Pets: Cat. Dog" etc); 2) A verb generation task, where participants were presented with objects and were required to generate related verbs. The high competition objects were related to a range of verbs (e.g., Penny: Spend"/"Pay"/"Buy" etc), and the low competition objects were related to one dominant verb (e.g., Scissors: "Cut"); 3) A name agreement task where a high competition condition involved naming low name agreement objects (e.g., Artist/Painter), and a low competition condition involved naming of high name agreement objects (e.g., Anchor), and; 4) A sentence completion task, where extrinsic competition was introduced via presentation of auditory distracters. The low competition distracters did not make sense (e.g., Barry wisely chose to pay the RANGE: "Bill"/"Cashier" etc), whereas the high competition distracters did (e.g., Barry wisely chose to pay the FINE: "Bill"/Cashier" etc). Our first hypothesis was that all participants would show high competition costs in increased response latencies and/or decreased accuracy. At the group level, this hypothesis was supported in all four tasks. At the individual level, there was mixed support as some participants showed predicted effects on the verb generation, name agreement, and sentence completion tasks. The second hypothesis was that exaggerated competition costs would occur in some or all non-fluent aphasics. At the group level this hypothesis was not clearly supported on any task. At the individual level there was mixed support, with some indications that non-fluents may be more likely to show significant competition effects than fluents. The third hypothesis was that non-fluent aphasics with relatively well preserved single word production but relatively impaired sentence production may be most likely to show exaggerated lexical competition effects. There was little support for this hypothesis. It was concluded that the data do not support the hypothesis that context-sensitive single-word production impairments are symptomatic of an impaired ability to resolve lexical competition. However, we have gained information on how heterogeneous aphasics perform on tasks that manipulate lexical competition, and we have gained some insights that may direct future research down a path towards more informative results, and increased knowledge on the complex process of speech production.</p>

Cerebral coherence in task-based fMRI hyperscanning: a new trick to an old dog

This study features an fMRI hyperscanning experiment, mapping the brains of the dyads from two fMRI sites, 305 km apart. There are two conditions: in half of the trials (the cooperation condition), the dyad had to collaborate to win and then split the reward, whereas in the other half (the competition condition), the winner took all the reward, thereby resulting in dynamic strategic interactions. Each subject took alternating turns as senders and receivers. To calculate the cerebral coherence in such jittered event-related fMRI tasks, we first estimated the feedback-related BOLD responses of each trial, using 8 finite impulse response functions (16 seconds), and then concatenated the beta volume series. With the right temporal-parietal junction (rTPJ) as the seed, the interpersonal connected brain areas in the cooperation and competition conditions were separately identified: the former condition with the right superior temporal gyrus (rSTG) and the latter with the left precuneus (lPrecuneus) (as well as some other regions of interest), both peaking at the designated frequency bin (1/16 s = 0.0625 Hz), but not in permuted pairs. In addition, the extended coherence analyses on shorter (12 s, or .083 Hz) and longer (20 s, or .05 Hz) concatenated volumes verified that only approximately in the trial length were the rTPJ-rSTG and rTPJ-lPrecuneus couplings found. In sum, our approach both showcases a flexible analysis method that widens the applicability of interpersonal coherence in the rapid event-related fMRI hyperscanning, and reveals a context-based interpersonal coupling between pairs in cooperation vs. competition.

Collaborations and deceptions in strategic interactions revealed by hyperscanning fMRI

Despite its ubiquity, deceiving as a social phenomenon is scarcely addressed with fMRI, partly due to the spontaneity and individual differences in cheating, and the contextual variability that fosters lying. In this hyperscanning fMRI study, the participant pairs (n=33) from Taipei and Tainan joined an opening-treasure-chest (OTC) game, where the dyads took alternative turns as senders (to inform) and receivers (to decide) for guessing the right chest. The cooperation condition was achieved by, upon successful guessing, splitting the $200NTD trial reward, thereby promoting mutual trust. The competition condition, in contrast, was done by, also upon winning, the latter receivers taking all the $150NTD reward, thereby encouraging strategic interactions. One key fMRI finding was the negative correlations between the connectivity of the right temporo-parietal junction (rTPJ), known as the theory-of-mind function, and amygdala, parahippocampal gyrus, and rostral anterior cingulate (rACC), to senders' behavioral lying rates. Furthermore, the Multi-Voxel Pattern Analysis (MVPA) over multiple searchlight-identified Region-Of-Interests (ROIs), in classifying either the "truthful vs. lying in $150" or the "truthful in $200 vs. truthful in $150" conditions achieved 61% and 84.5% accuracy, respectively, reflecting the idiosyncratic brain networks involved in distinguishing the social trust vs. deceptions in the dyadic interactions.

THE COMPETITIVENESS ANALYSIS OF EDIBLE BIRD NEST INDUSTRY IN MALAYSIA: APPLYING PORTER'S FIVE FORCE

The demand for EBN is continuous to growth and about 70 percent of world demand still cannot be fulfilled. Unfortunately, Malaysia only contributes 20 percent from world demand. The aims for this industry are to contribute about RM5 billion to Malaysian agricultural export and to achieve at least 40 percent of world demand. As being one of the most demanded EBN and being in the competition for leadership in world bird nest market, it can be specified that new market entrants and investments are important to fulfil the aims of government to this industry and for the growth of EBN industry. Thus, the objectives of this paper are to analysing the current competition condition of EBN industry in Malaysia and its opportunities for new entrants. This study revealed that the need of a huge capital and knowledge to conduct this business is essential and must come together. There is relatively low threat of substitution if the business premise is a shop lot. Despite the existence of buyer power in price negotiations, swiftlet house owners too could influence the process and assure themselves of higher markups when they organise a tender process with the help of the rancher’s association. Threat of rivalry is low especially with the setup of the rancher’s association to help each member who faced problems.

The effect of perceived interracial competition on psychological outcomes

There remains a dearth of research on causal roles of perceived interracial competition on psychological outcomes. Towards this end, this research experimentally manipulated perceptions of group-level competition between Black and White individuals in the U.S. and tested for effects on negative psychological outcomes. In Study 1 (N = 899), participants assigned to the high interracial competition condition (HRC) reported perceiving more discrimination, behavioral avoidance, intergroup anxiety, and interracial mistrust relative to low interracial competition (LRC) participants. Study 2 –a preregistered replication and extension—specifically recruited similar numbers of only Black and White participants (N = 1,823). Consistent with Study 1, Black and White participants in the HRC condition reported more discrimination, avoidance, anxiety, and mistrust. Main effects for race also emerged: Black participants perceived more interracial competition and negative outcomes. Racial income inequality moderated effects; competition effects were stronger in areas with higher levels of inequality. Implications for theory development are discussed.

Evolutionary Game Analysis on Strategies in “Main Manufacturer–Supplier” Mode Considering Technology Docking and Price Concluding under Competition Condition

This paper analyses the strategies of the substitutable suppliers competing to collaborate with a main manufacturer in “main manufacturer–supplier” (M-S) mode. In the research and development (R&D) of complex products, only one supplier can be chosen for one kind of part as a long-term collaboration partner with the manufacturer. The competition between substitutable suppliers focuses on the technology docking and price-concluding strategies. In this paper, one original supplier as the first-mover and one new supplier as the second-mover chose between the two strategies sequentially to compete for the collaborative preference of the manufacturer. We also took the delay cost brought by strategy changing into the consideration of the risks, which the suppliers and the manufacturer should prepare to share. With evolutionary game theory applied, we can conclude that the initial costs have little impact on suppliers’ making decisions, while the initial prices are correlated with both suppliers’ decision making. Results also show that hesitation and fluctuation periods exist in suppliers’ decision making, which have a relationship with existing strategy conditions, initial prices, and the cost caused by modifying the part. These results provide practical and reasonable managerial implications for M-S collaboration.

WECHAT, WERUN: A GROUP-BASED WALKING STUDY TO ENHANCE PHYSICAL ACTIVITY AMONG COMMUNITY-DWELLING OLDER ADULTS

The benefits of physical activity (PA) and social engagement for older adults are well established, yet the majority of adults over age 50 in the U.S. do not engage in regular exercise. We conducted a 4-week pre-post study with a one-month follow-up using a smart phone application called WeChat WeRun to explore the mechanisms of social engagement and competition to increase PA among older adults. Participants (N=40, mean age=65.7) were randomly assigned to one of two conditions. Participants in the activity competition condition used the WeRun to track their daily walking steps and interact via text with their group members for 4 weeks. The daily walking steps were displayed to the group and the participant with the highest daily steps in the group was indicated as the champion each day. Participants in the control group only used WeRun to track their own walking steps. Outcome variables included average weekly steps, exercise self-efficacy, and social engagement. The two-way repeated measures ANOVA results revealed that participants in the competition condition had higher average weekly steps and level of social engagement at the posttest, compared to those in the control group. Post hoc tests using the Bonferroni corrections revealed that the intervention increased their average weekly steps and social engagement from pretest to post-test, while these outcomes did not change in the control group. The effects were maintained at the one-month follow up. Discussion will consider the motivational role of competition and social interactions in increasing PA among older adults.

Investigation the Electronic Chain Supply Management System in a Competitive Atmosphere and by Attention to Environmental Issues

Nowadays, in a world that manufacturing enterprises are working under hard competition condition and produce. On the other hand, electronic chain supply management which is the result of using the internet in this kind of management has made the enterprises to evaluate the demands of costumes and helps them to reach their goals in a competitive atmosphere. In this way, enterprises do not pay attention to hazards of using different materials. The main purpose of this research is investigating the electronic chain management in a competitive atmosphere and the research shows that competitive pressure has a significant effect on the amount of acceptance of electronic chain supply management. Moreover, the positive and significant effect is observed in the acceptance of enterprises for electronic chain supply management for competing with competitors.