Frequency Of Finger Research Articles

Millisecond fluid pattern formation in the nip of a gravure printing machine

Rapid fluid splitting in a gravure printing press is studied using high-speed video imaging. The fluid flow and dynamics of the liquid-air meniscus in the wedge between a rigid printing cylinder and a planar substrate plate is singular at the contact point, and the capillary pressure behind the meniscus appears to diverge here. In case of lamella splitting conditions (in contrast to point splitting) a continuous meniscus is forming over the complete width of the contact zone. Spontaneous pattern formation, i.e. viscous fingering, is observed. We study the effect of a periodic gravure pattern on the movement of the liquid meniscus close to the nip. Differently from earlier observations on smooth surfaces we find that finger frequency does not algebraically scale with printing velocity, but exhibts a lock-in phenomenon. Pattern size scales with integer multiples of the raster width of the gravure pattern. We elaborate a tentative explanation for the rapid emptying of gravure cells in the moment of lift-off of the printing form and substrate, indicating that finger instability and cell emptying flows are mutually coupled by the local pressure gradients on the 10-μm scale.

Frequency of finger looking during finger counting is related to children's working memory capacities

ABSTRACTFinger counting can be useful in solving arithmetic problems, noticeably because it reduces the working memory demand of mental calculations. However, proprioceptive information might not be sufficient to keep track of the number of fingers raised during problem solving, and visual input may play an important role in this process. The present study was designed to address this question and shows that 8-year-old children look at their fingers in 60% of the trials during finger counting when solving additive problems. Moreover, our results reveal that the frequency of finger looking is negatively correlated with working memory capacities and is higher for more difficult problems. These findings suggest that finger looking is recruited in managing the cognitive demand of the arithmetic task, probably by providing additional external cues to monitor the number of steps that have to be incremented during finger counting.

Auditory-motor coupling of bilateral finger tapping in children with and without DCD compared to adults

The ability to modulate bilateral finger tapping in time to different frequencies of an auditory beat was studied. Twenty children, 7years of age, 10 with and 10 without developmental coordination disorder (DCD), and 10 adults tapped their left index and right middle fingers in an alternating pattern in time with an auditory signal for 15s (four trials each, randomly, at 0.8, 1.6, 2.4, 3.2Hz per finger). Dominant and non-dominant finger data were collapsed since no differences emerged. All three groups were able to modulate their finger frequency across trials to closely approximate the signal frequency but children with DCD were unable to slow down to the lowest frequency. Children with DCD were more variable in tap accuracy (SD of relative phase) and between finger coordination than typically developing children who were respectively more variable than the adults. Children with DCD were unable to consistently synchronize their finger with the beat. Adults were tightly synchronized and often ahead of the beat while children without DCD tended to be behind the beat. Overall, these results indicated that children with DCD can only broadly match their finger movements to an auditory signal with variability and poor synchronicity as key features of their auditory-fine-motor control. Individual inspection of the data revealed that five children with DCD had difficulty matching the slowest frequencies and that these children also had higher variability and lower percentile MABC scores from the movement assessment battery for children (MABC) than other children with DCD. Three children with DCD were more variable only at higher frequencies and two performed like typically developing children.

Bradykinesia in cirrhotic patients with early hepatic encephalopathy is related to a decreased glucose uptake of frontomesial cortical areas relevant for movement initiation

Bradykinesia is one of the first symptoms of hepatic encephalopathy (HE). Recently it has been suggested that bradykinesia in HE is due to disturbances in movement initiation. Areas involved in self-initiated movement are the motor- and premotor cortex, the supplementary motor cortex, the motor areas of the cingulate gyrus, and part of the frontomesial- and parietal cortex. The present study aimed to test the hypothesis that bradykinesia in HE is due to a functional disturbance of these areas. Fourteen cirrhotics with grade 0-I HE were examined. Patients with alcoholic cirrhosis or concomitant cerebral disorder were excluded. Patients underwent a 3-dimensional computer-assisted movement analysis for forearm pronation and supination, hand tapping and finger tapping and a (18)F-fluorodesoxy-glucose-PET-examination during rest, analysed with statistical parametric mapping (SPM99). The frequency of finger- and hand tapping was significantly correlated to the glucose metabolism of the motor area of the cingulate gyrus and frontomedial, frontodorsal and parietal cortical areas known to be activated with self-initiated movements. A decrease of movement frequency was associated with a reduction of glucose metabolism within these areas. These data support the hypothesis that bradykinesia in cirrhotics with HE is caused by an alteration of movement initiation.

A study of dermatoglyphics and the simian crease in familial deafness.

The frequency of finger and palmar dermatoglyphic patterns was studied in 239 patients with familial deafness, their 155 unaffected parents and siblings and 456 hearing school-children. Differences be