Puzzles

2011 ◽  
Author(s):  
Anany Levitin ◽  
Maria Levitin
Keyword(s):  
Ring Finger ◽  
Middle Finger ◽  
The Other ◽  
Left Hand ◽  
Matching Pair ◽  
The Right ◽  
Little Finger

1. A Wolf, a Goat, and a Cabbage A man finds himself on a riverbank with a wolf, a goat, and a head of cabbage. He needs to transport all three to the other side of the river in his boat. However, the boat has room for only the man himself and one other item (either the wolf, the goat, or the cabbage). In his absence, the wolf would eat the goat, and the goat would eat the cabbage. Show how the man can get all these “passengers” to the other side. 2. Glove Selection There are 20 gloves in a drawer: 5 pairs of black gloves, 3 pairs of brown, and 2 pairs of gray. You select the gloves in the dark and can check them only after a selection has been made. What is the smallest number of gloves you need to select to guarantee getting the following? (a) At least one matching pair (b) At least one matching pair of each color 3. Rectangle Dissection Find all values of n > 1 for which one can dissect a rectangle into n right triangles, and outline an algorithm for doing such a dissection. 4. Ferrying Soldiers A detachment of 25 soldiers must cross a wide and deep river with no bridge in sight. They notice two 12-year-old boys playing in a rowboat by the shore. The boat is so tiny, however, that it can only hold two boys or one soldier. How can the soldiers get across the river and leave the boys in joint possession of the boat? How many times does the boat pass from shore to shore in your algorithm? 5. Row and Column Exchanges Can one transform the left table in Figure 2.1 into the right table by exchanging its rows and columns? 6. Predicting a Finger Count A little girl counts from 1 to 1000 using the fingers of her left hand as follows. She starts by calling her thumb 1, the first finger 2, middle finger 3, ring finger 4, and little finger 5.

scholarly journals Bilateral anatomical variations of the hand extensors

2016 ◽  
Vol 15 (2) ◽  
pp. 278-282
Author(s):  
Humberto Ferreira Arquez
Keyword(s):  
Anatomical Variation ◽  
Medical Science ◽  
Ring Finger ◽  
Anatomical Variations ◽  
Extensor Digitorum ◽  
Left Hand ◽  
Extensor Tendons ◽  
Right Hand ◽  
The Right ◽  
Little Finger

Background: The purpose of this paper is to describe an anatomical variation of the hand extensor on the little finger of the right hand which receives four tendons, condition unknown, as it is the first case reported so far in the literature. The human extensor tendons of hand often display an array of variations. Awareness of the anatomy and variations of the extensor tendons on the dorsum of the hand is necessary not only for the anatomist but also for surgeons when considering tendons for hand surgery, tendon rerouting or transplants. Materials and Methods: Bilateral anatomical variation in the upper limb was found during routine dissection in a 75-year-old male cadaver in the Morphology Laboratory at the University of Pamplona. The variations were recorded and photographed. Result: In the left hand the extensor digitorum there was a single tendon to the index, double tendon to the middle, triple tendon to the ring finger, a single tendon to the little finger or digiti minimi. The extensor digiti minimi has double tendon. In the right hand the extensor digitorum there was a single tendon to the index, triple tendon to the middle finger, triple tendons to the ring finger, a double tendon to the little finger. The extensor digiti minimi has double tendon. The little finger receives four tendons, 2 of extensor digitorum and 2 of extensor digiti minimi. The dorsum of the left hand and right showed juncturae tendinum type 2, between the extensors tendons in the 3rd intermetacarpal space; type 3, between the extensors tendons in the 4th inter metacarpal space. Conclusion: The presence of multiple tendons may alter the kinematics around the site of attachment to the phalanx. Knowledge of anatomical variations and normal anatomy of the extensor tendons, may be helpful while performing graft and tendon transfer operations.Bangladesh Journal of Medical Science Vol.15(2) 2016 p.278-282

scholarly journals REGRESSION ANALYSIS TO DETERMINE STATURE FROM HAND ANTHROPOMETRY AMONG ILOCANO POPULATION IN PHILIPPINES FOR PERSON IDENTIFICATION

2021 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
T.Nataraja Moorthy
Keyword(s):  
Ring Finger ◽  
Middle Finger ◽  
Size Analysis ◽  
Human Hand ◽  
Regression Equations ◽  
Person Identification ◽  
Left Hand ◽  
Length Measurements ◽  
The Right ◽  
Hand Length

Stature determination aids the person identification during forensic investigation. The human hand research is the current topic of interest among forensic scientist, forensic medicine experts and anthropologists. Based on sample size analysis, the study involved consented 60 males and 60 females, age ranged from 18 to 55 years old. Stature and hand lengths measurements were made with Stadiometer and Vernier Calipers for analysis.  From each participant, ten hand length measurements, five from left and five from right hands were taken. The five length measurements in left hand are the inter-distance between the distal traverse crease of the wrist (LH) and tip of thumb (T), index finger (I), middle finger (M), ring finger (R) & little finger (L), as abbreviated LHT, LHI, LHM, LHR and LHL. Similarly, the right hand lengths indicated as RHT, RHI, RHM, RHR, and RHL.  The data were statistically analyzed by using SPSS software, version 23 and column chart. The information about age, gender, name, and place of origin of the participants was coded for easy reference. This study finally developed regression equations to determine stature from hand anthropometry among Ilocano population in Philippines for person identification

scholarly journals Analysis of the effect of fingertip size for sex differences in current perception thresholds with transcutaneous electrical stimulation in healthy subjects

2021 ◽  
Author(s):  
Shin-ichiro Seno ◽  
Hideaki Shimazu ◽  
Eiki Kogure ◽  
Atsushi Watanabe ◽  
Hiroko Kobayashi
Keyword(s):  
Sex Differences ◽  
Healthy Subjects ◽  
Index Finger ◽  
Ring Finger ◽  
Middle Finger ◽  
Perception Threshold ◽  
Left Hand ◽  
Current Perception Threshold ◽  
Males And Females ◽  
Little Finger

Abstract Objective This study aimed to measure the current perception threshold (CPT) of five fingertips of the left hand in healthy subjects and analyze whether sex differences in perception thresholds are suppressed when adjusting for fingertip size among males and females. Results For fingertips from the thumb to the little finger, the males’ CPT values were 1.03, 0.83, 0.86, 0.86, and 0.88 mA; the females’ results were 0.63, 0.55, 0.54, 0.51, and 0.50 mA. The CPTs were higher in males than in females for every fingertip. Upon adjusting for fingertip length, the log-transformed CPT values were found to have sex differences, except for the index finger: thumb, t(20.05) = 3.493, p = 0.002; middle finger, U(30) = 44.50, p = 0.005; ring finger, t(30) = 55.50, p = 0.018; little finger, U(30) = 30.00, p = 0.001. Similarly, the CPT values, transformed into log values when adjusting for the fingertip area, were found to have sex differences for three fingertips: thumb, t(18) = 2.649, p = 0.016; middle finger, U(20) = 12.00, p = 0.004; ring finger, t(18) = 2.206, p = 0.041. According to this study, sex differences in CPTs were not completely abolished by adjusting for fingertip length or area.

Choice Reaction Times for Structural Relationships between Possible Response Sequences

1993 ◽  
Vol 77 (3_suppl) ◽  
pp. 1203-1212 ◽  
Author(s):  
Kazunori Shidoji
Keyword(s):  
Index Finger ◽  
Ring Finger ◽  
Reaction Times ◽  
Middle Finger ◽  
Left Hand ◽  
Right Hand ◽  
Structural Relationships ◽  
Middle Ring ◽  
The Right ◽  
Choice Reaction Times

To investigate human motor programming, choice reaction times were measured on tasks for which subjects made choices between two alternative finger-tapping-movement sequences. The total-number-of-responses and the hierarchical editor models were tested. In Exp. 1 the choice was carried on the situations with the same total numbers of possible responses and different structural relations between alternative sequences. The right-hand reaction times in mirror choice (e.g., subject chose between the middle, index, and ring finger sequences of the left or right hand) were shorter than those in nonmirror choice (e.g., subject chose between the middle, index, and ring finger sequence on one hand and the middle, ring, and index finger sequence on the other hand); the total-number-of-responses model was not supported. In Exp. 2 two conditions had the same operation numbers of the hierarchical editor model. In Condition 1 subjects chose between the index finger of the right hand and the ring, index, and middle finger sequence of the left hand. In Condition 2 subjects chose between the index, ring, and middle finger sequences of the left or right hand. The reaction time in the former condition was shorter than that in the latter condition. Exp. 2 exhibited a counterexample of the hierarchical editor model that had been fairly robust in previous studies.

Functional Overlap of Finger Representations in Human SI and SII Cortices

2001 ◽  
Vol 86 (4) ◽  
pp. 1661-1665 ◽  
Author(s):  
Cristina Simões ◽  
Markus Mertens ◽  
Nina Forss ◽  
Veikko Jousmäki ◽  
Bernd Lütkenhöner ◽  
...  
Keyword(s):  
Index Finger ◽  
Ring Finger ◽  
Middle Finger ◽  
Response Latencies ◽  
Left Hand ◽  
Tactile Stimuli ◽  
Somatosensory Cortices ◽  
Somatosensory Evoked Fields ◽  
Left And Right ◽  
The Right

We aimed to find out to what extent functional representations of different fingers of the two hands overlap at the human primary and secondary somatosensory cortices SI and SII. Somatosensory evoked fields (SEFs) were recorded with a 306-channel neuromagnetometer from 8 subjects. Tactile stimuli, produced by diaphragms driven by compressed air, were delivered to the fingertips in three different conditions. First, the right index finger was stimulated once every 2 s. Then two other stimuli were interspersed, in different sessions, to right- or left-hand fingers (thumb, middle finger, or ring finger) between the successive right index finger stimuli. Strengths of the responses to right index finger stimuli were evaluated in each condition. Responses to right index finger stimuli were modeled by three current dipoles, located at the contralateral SI and the SII cortices of both hemispheres. The earliest SI responses, peaking around 65 ms, were suppressed by 18% ( P < 0.05) when the intervening stimuli were presented to the same hand; intervening stimuli to the other hand had no effect. The SII responses were bilaterally suppressed by intervening stimuli presented to either hand: in the left SII, the suppression was 39 and 42% ( P < 0.01) and in the right SII 67 and 72% ( P < 0.001) during left- and right-sided intervening stimuli, respectively. Left- and right-sided intervening stimuli affected similarly the SII responses and had no effect on the response latencies. The results indicate a strong and symmetric overlap of finger representations for both hands in the human SII cortices, and a weaker functional overlap for fingers of the same hand in the SI cortex.

An Analysis of Finger Pinch Strength in Children

1986 ◽  
Vol 30 (7) ◽  
pp. 667-671
Author(s):  
Sheik N. Irarhan
Keyword(s):  
Handgrip Strength ◽  
Ring Finger ◽  
Middle Finger ◽  
Pinch Strength ◽  
Maximal Strength ◽  
Strength Data ◽  
Left Hand ◽  
Right Hand ◽  
The Difference ◽  
The Right

This study examined 3 types of pinch strength and handgrip strength among children between the ages of 5.3 and 7.9 years. Maximal strength of four pulp pinches, the chuck pinch and the lateral pinch were measured as well as maximal handgrip strength. Data analysis showed that the chuck and lateral pinched were the strongest while the pulp pinch with the little finger was the weakest. The pulp pincnes with the index and with the middle finger were stronger than that with the ring finger. Males were slightly stronger than females, the difference being only 13%. The right hand pinches were not significantly stronger than left hand pinches, the difference being only 5%. The major hand of subjects with dominant left hand was only 84% as strong as the major hand of subjects with dominant right hand. Pinch strength increased with age by 50% for a 2.6 year difference.

Misperceived Positions of Interlaced Fingers

Perception ◽  
2019 ◽  
Vol 48 (9) ◽  
pp. 892-896
Author(s):  
Stuart Anstis
Keyword(s):  
Ring Finger ◽  
Middle Finger ◽  
Error Rates ◽  
The Other ◽  
The Right ◽  
As If

Interlacing one’s fingers can cause misperception of finger positions. Observer’s (O’s) fingers were interlaced in six different ways and experimenter (E) tapped two adjacent fingers in quick succession (e.g., tapping the right middle finger then the left ring finger). O had to state the perceived direction in which the tapping occurred, and errors were recorded. When hands were well separated, touching two adjacent fingers of one hand gave error rates of only 2.4%, and touching a finger on one hand then the other gave error rates of only 3.4%. Interlacing the fingers as if in prayer increased error rates to 9%. When hands were superimposed with finger pointing away from O’s body, error rates rose further to 30%. Observers knew which fingers were which, but they were confused about exactly where their fingers were. Thus, somatotopic was greatly superior to spatiotopic localization.

§ XI.—Hellenistic Mycenae

1923 ◽  
Vol 25 ◽  
pp. 408-428
Author(s):  
C. A. Boethius
Keyword(s):  
Common Type ◽  
The Other ◽  
The South ◽  
Left Hand ◽  
The Right

Among the ruins of the Hellenistic buildings at the south end of the Great Ramp, in the fourth or southern chamber (Pl. I. 34), three fragments of a stele (now in the Nauplia Museum) were found. The stele is of a simple and common type, and is made of the same white limestone as the other Mycenaean stele found by Tsountas, which it closely resembles even in its weathering. Except for the top left-hand corner and a gap on the right side the whole stele is preserved. It is ·969 m. in height, ·41–·436 m. in breadth (·41 m. at the ninth line of the inscription) and ·11–·125 m. thick. At the top there is a plain frieze, ·065 m. high : ·02 m. below the frieze begins an inscription which fills twenty lines and ends ·50 m. above the bottom of the stele. The letters are ·008–·01 m. high. The space between the lines is ·009–·011 m. The surface of the stone is very much worn, and it was consequently difficult to make out the letters and their accurate forms. The sketch (Fig. 93) shows the arrangement of the text.

scholarly journals Handedness results from complementary hemispheric dominance, not global hemispheric dominance: evidence from mechanically coupled bilateral movements

2018 ◽  
Vol 120 (2) ◽  
pp. 729-740 ◽  
Author(s):  
Elizabeth J. Woytowicz ◽  
Kelly P. Westlake ◽  
Jill Whitall ◽  
Robert L. Sainburg
Keyword(s):  
Motor Control ◽  
Dynamic Control ◽  
The Other ◽  
Hemispheric Dominance ◽  
Control Mechanisms ◽  
Left Hand ◽  
Right Hand ◽  
Other Hand ◽  
Task Component ◽  
The Right

Two contrasting views of handedness can be described as 1) complementary dominance, in which each hemisphere is specialized for different aspects of motor control, and 2) global dominance, in which the hemisphere contralateral to the dominant arm is specialized for all aspects of motor control. The present study sought to determine which motor lateralization hypothesis best predicts motor performance during common bilateral task of stabilizing an object (e.g., bread) with one hand while applying forces to the object (e.g., slicing) using the other hand. We designed an experimental equivalent of this task, performed in a virtual environment with the unseen arms supported by frictionless air-sleds. The hands were connected by a spring, and the task was to maintain the position of one hand while moving the other hand to a target. Thus the reaching hand was required to take account of the spring load to make smooth and accurate trajectories, while the stabilizer hand was required to impede the spring load to keep a constant position. Right-handed subjects performed two task sessions (right-hand reach and left-hand stabilize; left-hand reach and right-hand stabilize) with the order of the sessions counterbalanced between groups. Our results indicate a hand by task-component interaction such that the right hand showed straighter reaching performance whereas the left hand showed more stable holding performance. These findings provide support for the complementary dominance hypothesis and suggest that the specializations of each cerebral hemisphere for impedance and dynamic control mechanisms are expressed during bilateral interactive tasks. NEW & NOTEWORTHY We provide evidence for interlimb differences in bilateral coordination of reaching and stabilizing functions, demonstrating an advantage for the dominant and nondominant arms for distinct features of control. These results provide the first evidence for complementary specializations of each limb-hemisphere system for different aspects of control within the context of a complementary bilateral task.

scholarly journals Comparable behaviour of ring and little fingers due to an artificial reduction in thumb contribution to hold objects

2020 ◽  
Author(s):  
Banuvathy Rajakumar ◽  
Varadhan SKM
Keyword(s):  
Normal Force ◽  
Safety Margin ◽  
Ring Finger ◽  
Middle Finger ◽  
Human Hand ◽  
Mechanical Advantage ◽  
Free Condition ◽  
Normal Forces ◽  
Fixed Condition ◽  
Little Finger

AbstractBackgroundThe human hand plays a crucial role in accomplishing activities of daily living. The contribution of each finger in the human hand is remarkably unique in establishing object stabilization. According to the mechanical advantage hypothesis, the little finger tends to exert a greater normal force than the ring finger during a supination moment production task to stabilize the object. Similarly, during pronation, the index finger produces more normal force when compared with the middle finger. Hence, the central nervous system employs the peripheral fingers for torque generation to establish the equilibrium as they have a mechanical advantage of longer moment arms for normal force. In our study, we tested whether the mechanical advantage hypothesis is supported in a task in which the contribution of thumb was artificially reduced. We also computed the safety margin of the individual fingers and thumb.MethodologyFifteen participants used five-finger prismatic precision grip to hold a custom-built handle with a vertical railing on the thumb side. A slider platform was placed on the railing such that the thumb sensor could move either up or down. There were two experimental conditions. In the “Fixed” condition, the slider was mechanically fixed, and hence the thumb sensor could not move. In the “Free” condition, the slider platform on which the thumb sensor was placed could freely move. In both conditions, the instruction was to grasp and hold the handle (and the platform) in static equilibrium. We recorded tangential and normal forces of all the fingers.ResultsThe distribution of fingertip forces and moments changed depending on whether the thumb platform was movable (or not). In the free condition, the drop in the tangential force of thumb was counteracted by an increase in the normal force of the ring and little finger. Critically, the normal forces of the ring and little finger were statistically equivalent. The safety margin of the index and middle finger did not show a significant drop in the free condition when compared to fixed condition.ConclusionWe conclude that our results does not support the mechanical advantage hypothesis at least for the specific mechanical task considered in our study. In the free condition, the normal force of little finger was comparable to the normal force of the ring finger. Also, the safety margin of the thumb and ring finger increased to prevent slipping of the thumb platform and to maintain the handle in static equilibrium during the free condition. However, the rise in the safety margin of the ring finger was not compensated by a drop in the safety margin of the index and middle finger.

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