Double Skew-Dual Scaling: A Conjoint Scaling of Two Sets of Objects Related by a Dominance Matrix

Consider two sets of objects, {alpha(1), em leader, alpha(n)} and {beta(1), em leader, beta(m), such as n subjects solving m tasks, or n stimuli presented first and m stimuli presented second in a pairwise comparison experiment. Let any pair (alpha(i), beta(j)) be associated with a real number a(ij), interpreted as the degree of dominance of alpha(i) over beta(j) (e.g., the probability of alpha(i) relating in a certain way to beta(j)). Intuitively, the problem addressed in this paper is how to conjointly, in a "naturally" coordinated fashion, characterize the alpha-objects and beta-objects in terms of their overall tendency to dominate or be dominated. The gist of the solution is as follows. Let A denote the nxm matrix of a(ij) values, and let there be a class of monotonic transformations straight phi with nonnegative codomains. For a given straight phi, a complementary matrix B is defined so that straight phi(a(ij))+straight phi(b(ij))=const, and one computes vectors D(alpha) and D(beta) (the dominance values for alpha-objects and beta-objects) by solving the equations straight phi(A) straight phi(D(beta))/Sigma;straight phi(D(beta))=straight phi(D(alpha)) and straight phi(B(T)) straight phi(D(alpha))/Sigmastraight phi(D(alpha))=straight phi(D(beta)), where (T) is transposition, Sigma is the sum of elements, and straight phi applies elementwise. One also computes vectors S(alpha) and S(beta) (the subdominance values for alpha-objects and beta-objects) by solving the equations straight phi(B) straight phi(S(beta))/Sigmastraight phi(S(beta))=straight phi(S(alpha)) and straight phi(A(T)) straight phi(S(alpha))/Sigmastraight phi(S(alpha))=straight phi(S(beta)). The relationship between S-vectors and D-vectors is complex: intuitively, D(alpha) characterizes the tendency of an alpha-object to dominate beta-objects with large dominance values, whereas S(alpha) characterizes the tendency of an alpha-objects to fail to dominate beta-objects with large subdominance values. For classes containing more than one straight phi-transformation, one can choose an optimal straight phi as the one maximizing some measure of discrimination between individual elements of vectors straight phi(D(alpha)), straight phi(D(beta)), straight phi(S(alpha)), and straight phi(S(beta)), such as the product or minimum of these vectors' variances. The proposed analysis of dominance matrices has only superficial similarities with the classical dual scaling (Nishisato, 1980). Copyright 1999 Academic Press.     

Prenatal, perinatal and neonatal stimulation: a survey of neonatal nurseries

A recent survey was conducted on stimulation of mothers and babies during pregnancy and the neonatal period. The survey was responded to by 82 neonatology staff members from Neonatal Intensive Care Units (NICUs) at hospitals in the United States. Some forms of stimulation were extremely common including (1) skin-to-skin following birth in the delivery room (83% of hospitals); (2) containment (swaddling and surrounded by blanket rolls) in the NICU (86%); (3) music in the NICU (72%); (4) rocking in the NICU (85%); (5) kangaroo care (98%); (6) non-nutritive sucking during tubefeedings in the NICU (96%); and (7) breastfeeding in the NICU (100%). Other forms of stimulation occurred less frequently including (1) pregnancy massage (19%); (2) labor massage (30%); (3) the Doula (assistant who comforts during labor and delivery) (30%); (4) waterbeds in the NICU (23%); and (5) preterm infant massage in the NICU (38%).     

Personality patterns of suicide attempters: gender differences in Ukraine

In the present study, an attempt has been made to investigate the complete 'pattern' of a suicide attempter (SA) within the set of Big Five traits. Two models were used: M1, which includes the five main dimensions of Big Five in the analysis; and M2, which includes facets of those dimensions which were identified as important in M1. The study consisted of a group of SA (men - 326, women - 299) and a group of healthy volunteers (HV) (men - 143, women - 190) with a similar age range. Discriminant analysis (DA) showed that the factors most significant in discriminating the personality pattern of a male SA are (in decreasing order): (E) Extraversion, (N) Neuroticism, (C) Conscientiousness and (O) Openness; and for a female SA these factors were (E) Extraversion, (C) Conscientiousness and (A) Agreeableness. In M2 for men, the largest contribution to pattern recognition is (N3) Depression. Moreover, in M2 for men significant characteristics were (in descending order): (E6) Positive Emotions, (O1) Fantasy, (E4) Activity, and also (N2) Angry Hostility, (C3) Dutifulness, (C4) Achievement Striving, (C2) Order and (O6) Values; and for women: (E4) Activity, (C6) Deliberation, (C2) Order, (A6) Tender-Mindedness, (E5) Excitement Seeking, (E6) Positive Emotions, (C4) Achievement Striving, (A2) Straightforwardness, (C5) Self-Discipline and (E1) Warmth. Analysis of the obtained data demonstrates that suicide attempts amongst males, can largely be associated with personality variables reflecting negative emotions; while female suicide attempts are primarily associated with variables regarding activity and self-regulation.     

Unconditionally Selective Dependence of Random Variables on External Factors

What is the meaning of saying that random variables {X(1), em leader, X(n)} (such as aptitude scores or hypothetical response time components), not necessarily stochastically independent, are selectively influenced respectively by subsets {Gamma(1), em leader, Gamma(n)} of a factor set Phi upon which the joint distribution of {X(1), em leader, X(n)} is known to depend? One possible meaning of this statement, termed conditionally selective influence, is completely characterized in Dzhafarov (1999, Journal of Mathematical Psychology, 43, 123-157). The present paper focuses on another meaning, termed unconditionally selective influence. It occurs when two requirements are met. First, for i=1, em leader, n, the factor subset Gamma(i) is the set of all factors that effectively change the marginal distribution of X(i). Second, if {X(1), em leader, X(n)} are transformed so that all marginal distributions become the same (e.g., standard uniform or standard normal), the transformed variables are representable as well-behaved functions of the corresponding factor subsets {Gamma(1), em leader, Gamma(n)} and of some common set of sources of randomness whose distribution does not depend on any factors. Under the constraint that the factor subsets {Gamma(1), em leader, Gamma(n)} are disjoint, this paper establishes the necessary and sufficient structure of the joint distribution of {X(1), em leader, X(n)} under which they are unconditionally selectively influenced by {Gamma(1), em leader, Gamma(n)}. The unconditionally selective influence has two desirable properties, uniqueness and nestedness: {X(1), em leader, X(n)} cannot be influenced selectively by more than one partition {Gamma(1), em leader, Gamma(n)} of the factor set Phi, and the components of any subvector of {X(1), em leader, X(n)} are selectively influenced by the components of the corresponding subpartition of {Gamma(1), em leader, Gamma(n)}. Copyright 2001 Academic Press.     

Recursion, language, and starlings

It has been claimed that recursion is one of the properties that distinguishes human language from any other form of animal communication. Contrary to this claim, a recent study purports to demonstrate center-embedded recursion in starlings. I show that the performance of the birds in this study can be explained by a counting strategy, without any appreciation of center-embedding. To demonstrate that birds understand center-embedding of sequences of the form A(n) B(n) (such as A(1) A(2) B(2) B(1) , or A(3) A(4) A(5) B(5) B(4) B(3) ) would require not only that they discriminate such patterns from other patterns, but that they appreciate that elements must be bound from the outside in (thus, in the above examples, A(1) B(1) , A(2) B(2) , A(3) B(3) , A(4) B(4) , A(5) B(5) are bound pairs). This has not been shown in nonhuman species, and sentences with this structure are difficult even for humans to parse. There appears to be no evidence to date that nonhuman species understand recursion.     

高、低强迫症状个体的词语再认差异

比较了高强迫症状（High obsessive compulsive symptom, HOC）和低强迫症状（Low obsessive compulsive symptom, LOC）被试对于不同类型词语（强迫症敏感词、情绪词和中性词）再认成绩和记忆信心的差异。结果发现,HOC组记忆保存量显著低于LOC组（p<0.05）,表明HOC组对强迫症敏感词存在一定的偏好;通过对被试反应信心的检测和信号侦察论的应用,发现HOC组对中性词再认正误的判断觉察能力（d’值）低于LOC组（边缘显著：p＝0.054）;在正确反应信心上,被试类型和词语类型间存在交互作用,F(1,22)=4.60,p<0.05。本研究认为HOC组辨别能力的缺损可能导致其记忆信心方面的降低,这种假设还需要进一步的认知和脑功能研究来证实。     

A case-based approach to the development of practice-based competencies for accreditation of and training in graduate programs in genetic counseling

The American Board of Genetic Counseling (ABGC) sponsored a consensus development conference with participation from directors of graduate programs in genetic counseling, board members, and expert consultants. Using a collective, narrative, and case-based approach, 27 competencies were identified as embedded in the practice of genetic counseling. These competencies were organized into four domains of skills: Communication; Critical Thinking; Interpersonal, Counseling, and Psychosocial Assessment; and Professional Ethics and Values. The adoption of a competency framework for accreditation has a variety of implications for curriculum design and implementation. We report here the process by which a set of practice-based genetic counseling competencies have been derived; and in an accompanying article, the competencies themselves are provided. We also discuss the application of the competencies to graduate program accreditation as well as some of the implications competency-based standards may have for education and the genetic counseling profession. These guidelines may also serve as a basis for the continuing education of practicing genetic counselors and a performance evaluation tool in the workplace.The Consortium includes Directors of established graduate programs in genetic counseling and members of the ABGC Board of Directors who participated in the Consensus Development Conference held in January 1994: Diane Baker (University of Michigan/ABGC); Bonnie Baty (ABGC); Joan Burns (University of Wisconsin); Debra Collins (ABGC); Virginia Corson (ABGC); Beth Fine (Northwestern University/ABGC); Elizabeth Gettig (University of Pittsburgh); Verle Headings (Howard University); Jacqueline Hecht (University of Texas); Carl Huether (University of Cincinnati); Bonnie LeRoy (University of Minnesota); Joan Marks (Sarah Lawrence College); Anne Matthews (University of Colorado); Roberta Palmour (McGill University); Lorna Phelps (Medical College of Virginia); Kimberly Quaid (Indiana University); Joan Scott (ABGC); Ann Smith (ABGC); Helen Travers (ABGC); Judith Tsipis (Brandeis University); Ann Walker (University of California-Irvine/ABGC); Jon Weil (University of California-Berkeley); S. Robert Young (University of South Carolina); Randi Zinberg (Mount Sinai School of Medicine, New York).     

CONTRASTS AND INTERACTIONS REDUX:

Abstract— This reply to Abelson (this issue) and Petty, Fabrigar, Wegener, and Priester (this issue) is couched within the framework of five basic principles advising that we (1) hang on to what we predicted long enough to test it ( Tarzan's leap ), (2) be wary of beguiling statistical designs that may not address the question of interest (the Sirens' song), (3) not allow well-worn habits of thinking to ensnare our perceptions ( Lavoisier's crease ), (4) weigh the possibility of more than one correct hypothesis ( the dayyan's decree ), and (5) not confuse unplanned with planned contrasts ( the archer's aim ).     

Brightness for different surround conditions: the effect of transient glare

We measured the effect of a transient glare source on t heperceived brightness of astandard luminance (L(STD)) patch (0.5 cd/m2) as a function of the surround luminance (Ls). In the experiment, both increment and decrement stimuli were dependent on the value of the Ls (0.01, 0.2, 0.4, 0.6, 0.8, 1.0, 1.5, or 2.0 cd/m2). We adopted a magnitude comparison paradigm using constant stimuli to determine the test matching luminance (L(M)). When L(S) was lower than the luminance of the patch, which corresponds to increments, LM was lower than L(STD), and this effect was highest for the lowest L(S). There was a small but noticeable cusp as increments shifted to decrements. As L(S) increased further (i.e., as the decrement grew), L(M) flattened out below L(STF). The overall pattern of results could be interpreted in terms of the concept of contrast brightness, with consideration of the intrinsic differences in brightness evaluations between decrements and increments.     

Practice-based competencies for accreditation of and training in graduate programs in genetic counseling

In January 1996, the American Board of Genetic Counseling (ABGC) adopted 27 practice-based competencies as a standard for assessing the training of graduate students in genetic counseling. These competencies were identified and refined through a collective, narrative process that took place from January through November 1994, and included directors of graduate programs in genetic counseling, ABGC board members and expert consultants. These competencies now form the basis of the document Requirements for Graduate Programs in Genetic Counseling Seeking Accreditation by the American Board of Genetic Counseling (American Board of Genetic Counseling, 1996). The competencies are organized into four domains and are presented and discussed in this article.The Consortium includes Directors of established graduate programs in genetic counseling and members of the ABGC Board of Directors who participated in the Consensus Development Conference held in January, 1994: Diane Baker (University of Michigan/ABGC); Bonnie Baty (ABGC); Joan Burns (University of Wisconsin); Debra Collins (ABGC); Virginia Corson (ABGC); Beth Fine (Northwestern University/ABGC); Elizabeth Gettig (University of Pittsburgh); Verle Headings (Howard University); Jacqueline Hecht (University of Texas); Carl Huether (University of Cincinnati); Bonnie LeRoy (University of Minnesota); Joan Marks (Sarah Lawrence College); Anne Matthews (University of Colorado); Roberta Palmour (McGill University); Lorna Phelps (Medical College of Virginia); Kimberly Quaid (Indiana University); Joan Scott (ABGC); Ann Smith (ABGC); Helen Travers (ABGC); Judith Tsipis (Brandeis University); Ann Walker (University of California-Irvine/ABGC); Jon Weil (University of California-Berkeley); S. Robert Young (University of South Carolina); Randi Zinberg (Mount Sinai School of Medicine, New York).     

A review of the tip-of-the-tongue experience

The tip-of-the-tongue experience (TOT) has intrigued psychologists for nearly a century. R. Brown and McNeil (1966) provided the first systematic exploration of the phenomenon, and the findings since their seminal study suggest that TOTs (a) are a nearly universal experience, (b) occur about once a week, (c) increase with age, (d) are frequently elicited by proper names, (e) often enable access to the target word's first letter, (f) are often accompanied by words related to the target, and (g) are resolved during the experience about half of the time. Important questions remain concerning TOTs: (a) Are emotional reactions necessary, (b) do only low frequency targets elicit TOTs, (c) do TOTs reflect incomplete target word activation or interference from related words, and (d) do spontaneous retrievals really occur? A more precise definition of the TOT experience is needed, as well as greater uniformity in the information gathered during TOTs.     

Predictor variables for a 100-km race time in male ultra-marathoners

In 169 male 100-km ultra-marathoners, the variables of anthropometry, training, and prerace experience, in order to predict race time, were investigated. In the bivariate analysis, age (r = .24), body mass (r = .20), Body Mass Index (r = .29), circumference of upper arm (r = .26), percent body fat (r = .45), mean weekly running hours (r = -.21), mean weekly running kilometers (r = -.43), mean speed in training (r=-.56), personal best time in a marathon (r = .65), the number of finished 100-km ultra-runs (r = .24), and the personal best time in a 100-km ultra-run (r = .72) were associated with race time. Stepwise multiple regression showed that training speed (p < .0001), mean weekly running kilometers (p < .0001), and age (p < .0001) were the best correlations for a 100-km race time. Performance may be predicted (n=169, r2 = .43) by the following equation: 100-km race time (min) = 1085.60 - 36.26 x (training speed, km/hr.) - 1.43 x (training volume, km/wk.) + 2.50 x (age, yr.). Overall, intensity of training might be more important for a successful outcome in a 100-km race than anthropometric attributes. Motivation to train intensely for such an ultra-endurance run should be explored as this might be the key for a successful finish.     

Reentry Women: A Literature Review With Recommendations for Counseling and Research

This article is a comprehensive literature review of the research regarding reentry women for 1980 to 1990, with recommendations for counseling and research. The article is divided into the following sections: (a) reentry trends; (b) general characteristics; (c) reasons for reentry; (d) personality; (e) role, values, and family; (f) satisfaction in the student role; (g) career choice; (h) reentry women after graduation; (i) research limitations; (j) research recommendations; and (k) conclusion. Research replications were found to be very limited and restricted to four areas: (a) reasons for reentry, (b) personality, (c) family variables, and (d) career choice.     

癌症病人的生活质量及心理干预研究

本研究在前期研究的基础上进一步探讨癌症病人的生活质量状况和心理干预的效果。运用病例对照实验设计 ,选用生活质量问卷 (QLQ C3 0 )作为主要测查工具 ,采用两因素混合实验方差分析统计方法 ,对 1 2 0名住院化疗病人进行了比较分析。结果显示 :躯体功能 (PF)、角色功能 (RF)、情绪功能(EF)、认知功能 (CF)和整体生活质量 (QL)得分在治疗前后和实验与对照组之间的交互作用均显著和非常显著 ;症状量表和单项症状中交互作用显著和非常显著的有 :疲乏 (FA)、呼吸困难 (DY)、失眠 (SL)、食欲丧失 (AP)。因此 ,化疗对病人的生活质量有明显的影响 ,经心理干预后癌症病人的各种功能状况和症状得到不同程度的改善。     

Paths from socioemotional behavior in middle childhood to personality in middle adulthood

Continuity in individual differences from socioemotional behavior in middle childhood to personality characteristics in middle adulthood was examined on the assumption that they share certain temperament-related elements. Socioemotional characteristics were measured using teacher ratings at ages 8 (N = 369; 53% males) and 14 (95% of the initial sample). Personality was assessed at age 42 (63% of the initial sample; 50% males) using a shortened version of the NEO Personality Inventory (NEO-PI); the Karolinska Scales of Personality (KSP); and the Adult Temperament Questionnaire (ATQ). Three models were tested using structural equation modeling. The results confirmed paths (a) from behavioral activity to adult Extraversion and Openness (NEO-PI), sociability (KSP), and surgency (ATQ); (b) from well-controlled behavior to adult conformity (KSP) and Conscientiousness (NEO-PI); and (c) from negative emotionality to adult aggression (KSP). The paths were significant only for one gender, and more frequently for males than for females. The significant male paths from behavioral activity to all indicators of adult activity and from well-controlled behavior to adult conformity started at age 8, whereas significant female paths from behavioral activity to adult sociability and from well-controlled behavior to adult Conscientiousness started at age 14. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Salutary proximal processes and distal mood and anxiety vulnerability outcomes of mindfulness training: a pilot preventive intervention

The present study evaluated the effect of a brief mindfulness-based preventive intervention on (a) dispositional (MAAS; Brown & Ryan, 2003) and state (SMS; Tanay & Bernstein, 2010) mindfulness; (b) putative proximal factors/processes engendered through the development of mindfulness, including increased decentering (EQ-D; Fresco et al., 2007) and reduced experiential avoidance (AAQ; Hayes et al., 2004); and (c) distal mood and anxiety vulnerability factors, including reduced depression-related dysfunctional attitudes, (DAS; de Graaf, Roelofs, & Huibers, 2009), anxiety sensitivity (ASI-3; Taylor et al., 2007), and negative affectivity (PANAS-NA; Watson, Clark, & Tellegen, 1988) among a university-community sample in Israel. Fifty-three adult participants between the ages of 20 and 52 (M(age)=25.2 years, SD(age)=4.3 years; 65.4% women) were recruited from the Haifa University community. Nineteen participants were randomly assigned to an experimental condition (M(age)=25.3 years, SD(age)=4.3 years; 66% women) and studied prospectively over the course of a four-session (21-day) mindfulness skills training intervention; and 34 participants were randomly assigned to a no-intervention (control) condition (M(age)=24.9 years, SD(age)=2.4years; 64.7% women) and studied prospectively. Findings demonstrate statistically robust and clinically significant relations between mindfulness and the theorized proximal and distal mood and anxiety vulnerability factors. Findings are discussed with respect to their theoretical implications for better understanding mindfulness-psychopathology vulnerability relations, clinical implications for larger-scale universal and selective transdiagnostic prevention efforts, and future directions for this area of research.     

An n-dimensional Weber Law and the Corresponding Fechner Law

Weber's law of 1834, DeltaS/S=c for the just noticeable difference (jnd), can be written as S+DeltaS=kS, k=1+c. It follows that the stimulus decrement required to elicit one jnd of sensation is S-DeltaS*=k(-1)S. If generalized for two stimulus dimensions and two corresponding response dimensions, Weber's law would have to state such equations for all directions of change in the plane. A two-dimensional Weber law with exactly these properties is realized by [S(x)+DeltaS(x)(straight theta), S(y)+DeltaS(y)(straight theta)]=[k(sin(straight theta))S(x), k(cos(straight theta))S(y)] which determines the stimulus coordinates for all stimuli just noticeably different from the stimulus (S(x), S(y)) in all directions 0R(2)) is [x, y]mapsto[log(k)(x), log(k)(y)]. The solution is generalized to arbitrarily many dimensions by substituting the sin and cos in the generalized Weber law by the standard coordinates of a unit vector. Copyright 2000 Academic Press.     

Role of L-type Ca2+ channel isoforms in the extinction of conditioned fear

Dihydropyridine (DHP) L-type Ca(2+) channel (LTCC) antagonists, such as nifedipine, have been reported to impair the extinction of conditioned fear without interfering with its acquisition. Identification of the LTCC isoforms mediating this DHP effect is an essential basis to reveal their role as potential drug targets for the treatment of specific anxiety disorders. Ca(V)1.2 and Ca(V)1.3 are the predominant LTCCs in the mammalian brain. However, since no isoform-selective DHP blockers are available, their individual contribution to fear memory extinction is unknown. We used a novel mouse model expressing DHP-insensitive Ca(V)1.2 LTCCs (Ca(V)1.2DHP(-/-) mice) to address this question. In line with previous studies, wild-type (WT) mice treated with systemic nifedipine displayed markedly impaired fear extinction. This DHP effect was completely abolished in Ca(V)1.2DHP(-/-) mice, indicating that it is mediated by Ca(V)1.2, but not by Ca(V)1.3 LTCCs. Supporting this conclusion, Ca(V)1.3-deficient mice (Ca(V)1.3(-/-)) showed extinction identical to the respective WT mice. The inhibition of fear extinction was not observed after intracerebroventricular (i.c.v.) application of different doses of nifedipine, suggesting that this effect is secondary to inhibition of peripheral Ca(V)1.2 channels. The LTCC activator BayK, which lacks neurotoxic effects in Ca(V)1.2DHP(-/-) mice, did not influence the extinction time course. In summary, we demonstrate that LTCC signaling through the Ca(V)1.2 isoform of LTCCs interferes with fear memory extinction, presumably via a peripherally mediated mechanism. Activation of other LTCC isoforms (predominantly Ca(V)1.3) is not sufficient to accelerate extinction of conditioned fear in mice.     

Microswitch programs for persons with multiple disabilities: an overview of the responses adopted for microswitch activation

Background: To introduce a person with multiple disabilities to a microswitch-aided program, one has to select a plausible response(s), that is, a response(s) that can be performed reliably and without excessive effort by the person and can successfully activate the microswitch(es) available (producing preferred stimuli). This paper provides an overview of the responses adopted for microswitch activation in research studies during the last 20 years. Method: Computerized and manual searches were carried out to identify the studies published between 1986 and 2005. Forty-eight research studies were identified. They concerned the use of (1) a single (typical) response, (2) a single (non-typical) response, (3) multiple (typical and non-typical) responses, and (4) multiple (vocal) responses. Results and discussion: The results showed that 151 of the 190 participants involved in the studies had a positive outcome (i.e., clear increases in their responding, which suggested that they had learned the association between responding and consequent preferred stimuli). Failures were largely concentrated in the first group of studies. The discussion focused on (a) the importance of selecting plausible responses for increasing the chances of success, (b) the need of non-typical responses for persons with minimal motor behavior, (c) implications of programs with multiple responses on engagement and choice, and (d) relevance of using vocal utterances. Some suggestions for future research concerning these points were also examined.     

Rhythmic performance during a whole body movement: dynamic analysis of force-time curves

The purpose of this study was to investigate rhythmic performance during two-legged hopping in place. In particular, it was tested whether (a) timing control is independent of force control, (b) a dynamic timer model explains rhythmic performance, and (c) it is a force related parameter that carries the timing information. Eleven participants performed two-legged hopping at their preferred hopping frequency (PHF) and at two hopping frequencies set by an external rhythmic stimulus as lower (LHF) and higher (HHF) than their PHF, respectively. A force plate was used to record the ground reaction force (GRF) time curves during two-legged hopping. The primary temporal and force related parameters determined from the GRF-time curves were the durations of the cycle of movement (t(cycle)), of the contact phase (t(contact)), of the flight phase (t(flight)), the magnitude of peak force (Fz(peak)) and the rate of peak force development (RFD). Control of t(cycle) was independent of force control as shown by the non-significant correlations between t(cycle) and the force parameters of the GRF-time curve. Lag 1 autocorrelations of t(cycle) were not significant in any of the HF, thereby a dynamic timer model is considered to explain the timing of t(cycle) during two-legged hopping. RFD varied more than any other GRF-time curve parameter, exhibited consistent significant strong correlations with the GRF-time curve parameters and significant negative lag 1 autocorrelations in PHF, thus, it was highlighted as the potent timing control parameter. Finally, we provide a practical application for the optimization of rhythmic performance.