The role of speed and incline in the spontaneous choice of technique in classical roller-skiing

Cross-country skiers change technique depending on terrain (incline) and effort (work rate; speed at a particular incline or resistance). The literature is not unequivocal about the influence of incline or speed on the choice of technique, i.e., which of these act as a ‘control parameter’. Identifying task related control parameters for spontaneous technique shifts assists elucidating which mechanisms are active for triggering technique transitions. The aim of this study was to investigate whether speed or incline acted as such control parameter for technique shifts during classic style roller skiing. In this study, we kept the exercise intensity constant while changing two potential control parameters (speed and incline). Thus, any effect of work rate was excluded.Eight male competitive cross-country skiers performed roller skiing on a treadmill while incline was altered from 3 to 11% and back to 3% each minute by 1% and speed changed accordingly to obtain a constant work rate. This protocol was performed at three submaximal work rates (170, 200, and 230 W) to obtain various combinations of speed and incline.The athletes were free to choose their technique (double poling, double poling with kick and diagonal stride), which was identified using continuous phase analysis on the motion of the skis. Physiological response (heart rate, oxygen uptake) was recorded continuously.The incline seemed to affect choice of technique shift more than speed: the ANOVA for repeated measures on all work rates showed no significant effect of incline (p > 0.2) and an effect for speed (p < 0.001). No effect of protocol order (increasing versus decreasing incline) was found for transitions. The physiological response was lowest for conditions of steep incline-low speed and was affected by protocol order. Cycle rate was affected by incline only in the double poling technique.Possible mechanisms related to the triggering of technique transitions are discussed.     

Emergent complexity: What uphill analysis or downhill invention cannot do

In these notes we review emergent phenomena in complex systems, emphasizing ways to identify potential underlying universal mechanisms that generate complexity. The discussion focuses on the emergence of collective behavior in dynamical systems when they are poised near a critical point of a phase transition, either by tuning or by self-organization. We then present the rationale for our proposal that the brain is naturally poised near criticality and review recent results as well as the implications of this view of the functioning brain.     

Adolescent anxiety and aggression can be differentially predicted by electrocortical phase reset variables

Increasing evidence supports the notion that both internalizing (e.g., anxiety) and externalizing (e.g., aggression) behavioral dysregulation are associated with abnormal communication between brain regions. Electroencephalographic (EEG) signals across two electrode sites are said to be coherent with one another when they show consistent phase relations. However, periods of desynchrony with shifting of phase relations are a necessary aspect of information processing. The components of EEG phase reset (‘locking’ when two regions remain in synchrony, and ‘shifting’ when the two regions desynchronize momentarily) show dramatic changes across development. We collected resting EEG data from typically developing 12 to 15-year-olds and calculated phase shift and lock values in the alpha frequency band across 14 pairs of electrodes varying in inter-electrode distance. A composite measure of participants’ aggression levels was positively associated with phase shifting, particularly in the low alpha frequency range, most strongly over the left hemisphere, consistent with the relatively greater left-prefrontal activity reported in aggressive adults. A composite measure of anxiety levels was positively associated with alpha phase locking at sites over both hemispheres, consistent with changes in connectivity reported during anxious thinking in adults. Associations with anxiety could not be explained by traditional EEG coherence measures and suggest that phase shifting and locking might provide an important non-invasive associate of clinically problematic behavior.     

Quantum perichoresis: Quantum field theory and the Trinity

The main thesis of this article is that the Trinitarian theological doctrine of perichoresis can be metaphorically interpreted as a form of Divine phase entanglement with the world. Such entanglement would entail non-local, relational holism and superposition through which the immanent unity of the Trinity is economically present in creation. Christ kenoticly empties himself of the immanent perichoresis of the Trinity in order to enter the economic perichoresis of the creation. The Spirit is then the continuing perichoretic love of God sanctifying the creation toward life and fulfillment from within. It is the Trinity in ongoing perichoretic entanglement with the creation, affirming Divine ubiquity and panentheism.     

Why the brain needs language in order to be self-conscious

It has been argued that natural language, in the form of inner speech, plays a central role in self-consciousness. However, it is not quite clear why. In this paper, we present a novel answer to the why question. According to the thesis presented in this paper, the brain as a physical system is limited in observing itself and relies on the mediation of natural language for the reconstruction of its phase space trajectory. Drawing on knowledge gathered on the measurement of dynamical systems, we detail the unique properties of natural language that may support this reconstruction.     

In situ transformation from P phase to μ phase in rhenium-containing single-crystal superalloy during thermal exposure

An in situ phase transformation from P to μ in a rhenium-containing superalloy during high-temperature exposure has been investigated by transmission electron microscopy. The orientation relationship between the phases is found as (1–12)_μ // (1?0?0)_P and [2?4?1]_μ // [0?1?1]_P. An atomic model of the μ/P interface was built to reveal a perfectly coherent interface with lattice misfits of only 0.421 and 1.098%. Considering the small lattice distortions and the similar elemental composition of the phases, it is concluded that the phase transformation from P to μ is favourable.     

Family expressed emotion prior to onset of psychosis

This study compared components of expressed emotion (EE; rejection, warmth, protectiveness, and fusion) across three samples: two in which the subjects had an established schizophrenic or mood disorder, and a third in which the subjects were at high risk for an initial psychosis. METHODS: Family members rated themselves on the Social Adjustment Scale-III and, in the prodromal sample, estimated the duration of the prodrome. RESULTS: Scores were all but identical in the two established-disorder samples but were markedly higher than scores in the prodromal sample on all four factors. In mothers, warmth (decreasing), rejection, protectiveness, and fusion (increasing) were significantly correlated with duration of prodrome, whereas for fathers, warmth and protectiveness were similarly correlated. CONCLUSION: These data suggest that expressed emotion is largely reactive to deterioration manifested by the young person developing a psychotic disorder, rather than a trait of family members.     

The perception of available social support is related to reduced cardiovascular reactivity in phase II cardiac rehabilitation patients

Objective  Numerous studies have observed a relationship between social support (SS) and post coronary event survival. Laboratory research suggests one mechanism regulating this relationship may be exaggerated cardiovascular reactivity (CVR). What has not been as well explored is (1) whether the SS-CVR relationship holds up for a heart diseased sample, and (2) whether this relationship is evidenced only in supportive environments or can be found as a function of generalized perception of being socially supported. Thus, the purpose of this study was to examine the relationship of perceived SS and a locally supportive presence to CVR to a speech-induced stressor in post coronary event patients. Method  Forty-one Phase II cardiac rehabilitation patients participated in a research protocol that consisted of BP and HR measurement during two identical affective stress interviews where local support was systematically varied by presence or absence of a friendly small pet dog. Perception of SS was assessed by completion of psychosocial questionnaire packet that included measures of SS, anger expression and pet attachment. Results  Repeated measures ANCOVAs revealed that patients who believed they had greater SS available to them during difficult times exhibited significantly less CVR for MAP (p<.007) and DBP (p<.024). No significant main effects for local support (pet presence) and no interactions between local and perceived support were found. Conclusions  These findings are of interest as they: (a) demonstrate an association between reduced CVR and higher (amounts of) SS in a clinical sample; (b) demonstrate this effect in a sample medicated to dampen CV levels and surges; (c) suggest that perceived amount of SS provides an ameliorative influence on CVR independent of situational support; (d) suggest that for certain conditions pet-models of support may be ineffective at establishing an local support presence.     

Identification and integration of sensory modalities: Neural basis and relation to consciousness

A key question in studying consciousness is how neural operations in the brain can identify streams of sensory input as belonging to distinct modalities, which contributes to the representation of qualitatively different experiences. The basis for identification of modalities is proposed to be constituted by self-organized comparative operations across a network of unimodal and multimodal sensory areas. However, such network interactions alone cannot answer the question how sensory feature detectors collectively account for an integrated, yet phenomenally differentiated experiential content. This problem turns out to be different from, although related to, the binding problem. It is proposed that the neural correlate of an enriched, multimodal experience is constituted by the attractor state of a dynamic associative network. Within this network, unimodal and multimodal sensory maps continuously interact to influence each other’s attractor state, so that a feature change in one modality results in a fast re-coding of feature information in another modality. In this scheme, feature detection is coded by firing-rate, whereas firing phase codes relational aspects.     

Necessary condition for forward progression in ballistic walking

Ballistic walking requires an appropriate configuration of posture and velocity at toe-off to avoid backward falling. In this study, we investigated a determinant of the state of the body center of mass (COM) at the toe-off with regard to ballistic walking. We used an inverted pendulum model to represent ballistic trajectories and the necessary condition for forward progression by a simple relationship between the COM states (position and velocity) at toe-off. This condition was validated through a computer simulation of a 7-link musculoskeletal model and measurement experiments of human movements involving stepping and walking. The results of the model simulation were in good agreement with some of the results predicted by the inverted pendulum model. The measurement experiments of walking and stepping movements showed that most COM states at toe-off satisfied the condition for forward progression and the measured trajectories during single support phase were similar to the ballistic trajectories although humans are capable of walking in non-ballistic ways. These results suggested that the necessary condition for forward progression can predict the COM states at toe-off for efficient movement and for avoiding backward falling during single support phase.