Ridge Density Research Articles

Thai Twin Registry: Description of the Initial Stage

The present study describes the initial phase of the Thai Twin Registry (TTR) in Khon Kaen University, a pioneer research university located in the Northeast of Thailand. The initial steps of the study included the analysis of dermatoglyphic information in Thai twins for answering the research question: Are monozygotic (MZ) and dizygotic (DZ) twins different in dermatoglyphic variables? Subjects were 212 twin pairs (131 MZ and 81 [corrected] DZ), consisting of 155 males and 269 females. Four types of fingerprint pattern (FP) - that is, arch, radial loop, ulnar loop, and whorl - were classified and analyzed and compared between MZ and DZ twins. The arch radial loop and whorl frequencies differ between MZ and DZ twins. When comparing FP in each finger, only the right little finger shows a statistically different FP, while the FP similarity average from 10 homologous fingers of co-twins was greater in MZ than DZ twins. By using the Area Under the Receiver Operating Characteristic curve analysis, the MZ twins could be differentiated from DZ twins by the FP similarity. Summarizing, this valuable report about TTR was conducted by analysis of FP data, which indicated that the MZ and DZ twins exhibited FP pattern and FP similarity differences. Other dermatoglyphic studies of the existing FP database, such as finger ridge count, finger ridge density, and minutia, will be considered for ongoing research at the TTR.

A study of sex differences in fingerprint ridge density in a North Indian young adult population

Fingerprints have considerable value in morphological, biological, anthropological and forensic studies. Fingerprints collected from the crime scene and from the items of evidence of crime have been successfully used to identify suspects, victims or any other person who had touched the surface in question. The thickness of epidermal ridges varies between individuals; females are supposed to have finer ridges than males and therefore a greater ridge density. The present research is an attempt to distinguish sex from fingerprint ridge density in the radial, ulnar and lower areas of a fingerprint in a North Indian population. A total of 194 individuals (97 males and 97 females) aged between 18 and 25 years were included in the study and fingerprints were collected from each finger of the participants. Thus, a total of 1940 fingerprints were obtained and epidermal ridges were counted in the radial, ulnar, and lower areas of each fingerprint. The radial and ulnar areas are the 5 mm × 5 mm areas on the radial and ulnar side of the central core respectively while the lower area is designated as 5 mm × 5 mm area adjoining the flexion crease of the terminal phalanx on a fingerprint. The fingerprint ridge density in radial, ulnar and lower areas and between sexes was compared statistically using t-test. The results indicate that the females tend to have a significantly higher ridge density than males in the three areas analyzed in the study. The fingerprint ridge density in the ulnar and radial areas of the fingerprints is significantly higher than the lower area. The present study suggests that the fingerprint ridge density can be a relevant and useful morphological parameter in distinguishing sex of a latent fingerprint of unknown origin from the scene of crime. The findings can also be useful in identification of mutilated remains when a dismembered hand is brought for medico-legal examination.

Is there a sex difference in palm print ridge density?

Analysis of fingerprints and palm prints at the crime scene is vital to identify the suspect and establish a crime. Dermatoglyphics can even be valuable in identification of a dismembered hand during medicolegal investigations to establish the identity of an individual in cases of mass disasters/mass homicides. The present research studies the variation in ridge density in different areas of the palm prints among men and women. The four prominent areas were analysed on the palm prints that included central prominent part of the thenar eminence (P1), hypothenar region; inner to the proximal axial triradius (P2), medial mount; proximal to the triradius of the second digit (P3) and lateral mount; proximal to the triradius of the fifth digit (P4). The mean palm print ridge density was significantly higher among women than men in all the designated areas in both hands except for the P3 area in the right hand. Statistically significant differences were observed in the palm print ridge density between the different palm areas in men and women in right and left hands. No significant right-left differences were observed in the palm print ridge density in any of the four areas of palm prints among men. In women, right-left differences were observed only in the P3 and P4 areas of palm prints. This preliminary study indicates that though the palm print ridge density is a sexually dimorphic variable, its utility for estimation of sex in forensic identification may be limited owing to significant overlapping of values.

Facile Synthesis and Morphology Control of Bamboo-Type TiO2 Nanotube Arrays for High-Efficiency Dye-Sensitized Solar Cells

We report fast synthesis of bamboo-type TiO2 nanotube arrays via anodization of Ti in nonhazardous electrolyte under alternating voltage condition for applications as photoanodes in high-efficiency dye-sensitized solar cells (DSSCs). Formation mechanism of bamboo-type nanotubes is also explored. The low-voltage step reduces pH and ion-diffusion gradient inside TiO2 nanotubes and induces formation of bamboo ridges on outer tube walls when a second high-voltage step is conducted. Ridge spacing and length of bamboo-type nanotubes can be facilely tuned by adjusting time of high-voltage step and electrolyte composition. All DSSCs based on bamboo-type TiO2 nanotube arrays show higher efficiencies than those based on smooth-walled nanotubes with the same tube length due to enhanced surface area of bamboo-type nanotubes for dye loading. It is also noted that DSSC efficiency increases with the ridge density of bamboo-type nanotubes of the same length. For example, DSSC based on bamboo-type nanotubes (8 μm long) wi...

Sex identification from fingertip features in Egyptian population

Identification of an individual plays a vital part of any medico-legal investigation. Fingerprints are considered to be one of the most reliable methods of identification. The present study was conducted on 752 healthy adult Egyptian subjects (380 males and 372 females) with age ranged from 20 to 30 years. Consents were obtained from all participants and their 10 digits were photographed to determine the sexual dimorphism by some fingertip features (ridge count, square area, finger breadth and finally ridge density) in Egyptians. Statistical analysis was made using a multivariate logistic regression variation analyses. Results showed that females tend to have statistically significant shorter (narrower) finger breadth (right: male > 9.54 ≥ female, left: male > 9.38 ≥ female), smaller square area (right: male ≥ 16.1 > female, left: male > 15.1 ≥ female), more ridge count (right: female > 21.0 ≥ male, left: female > 21.2 ≥ male), and higher ridge density (right: female >1.35 ≥ male, left: female > 1.5 ≥ male) when compared with males. The ridge density of the left hand was the most single accurate parameter in correct sex determination. The best classification accuracy of 82% was generated upon combining ridge count, square area and ridge density. It was concluded that fingertip features of Egyptians can be used by medico-legal experts for accurate sex identification.

An analysis of fingerprint ridge density in the Indo-Mauritian population and its application to gender determination

Gender determination is an important aspect of personal identification, which is often required in medicolegal practice. Many experts believe that there are finer and more epidermal ridges on the fingers of women as compared with men. However, it is important to establish numerical cut-off values in terms of ridge counts to facilitate the gender determination within a particular population. The present study was conducted in the Department of Forensic Medicine, SSR Medical College, Mauritius with the objective to describe the ridge density in the Indo-Mauritian population and to devise a numerical model which is capable of identifying the sex of an individual from this population on the basis of the ridge counts obtained from the corresponding finger prints. The study was focused on 200 healthy medical students (100 men and 100 women) within the age range of 20-30 years. Multivariate analysis of variance results shows a significant gender difference in the sense that women tend to have higher ridge density then men in the distal region of all 10 digits (F = 41.83, P ≤ 0.005). The maximum mean ridge density over all fingers in men (12.26∼12) is less than the minimum mean ridge density over all fingers in women (12.71∼13). A linear discriminant function is derived from numerical modelling, which is used to predict (with a high reliability index, 0.92) the sex of the person whose fingerprints are obtained.

표준 주름판을 이용한 주름 구성요소 분석

In order to provide a fundamental understanding of cloth surface smoothness, the wrinkle components in the AATCC standard replica were studied. Using an image acquisition system with a line light source and a camera, images of the replica were obtained. Four images of each replication were taken at intervals of <TEX>$90^{\circ}$</TEX> degree rotations. The wrinkle ridges in the image were extracted using Canny edge detection, while the shade generated by the wrinkles was obtained using line threshold method. The ridge density, the distribution of ridge-to-ridge distance and the shade length distribution were measured and calculated. The three factors measured showed a strong non-linear relationship with the replication grades.

Variability of Finger Ridge Density among Thai Adolescents

Finger ridge density (RD) is the number of finger ridges that touch the diagonal line drawn between a square of 25 mm2 which is placed on the core of the fingerprint image. It has been useful as a sex determination aid in forensic practice as its values are significantly higher in females than males. The present study was aimed at investigating the RD of Thai adolescents aged between 10 and 12 years old. Subjects were 130 schoolboys and 130 schoolgirls were randomly selected and signed informed consent forms prior to printing each individual’s ten fingers by using the adhesive transparent tape technique. The Microsoft Word program was applied for precise counting of RD. The mean RD differences between left and right hands, boys and girls, radial and ulnar areas were statistically tested. The likelihood ratio was computed to obtain the probability inferences of sex, and posterior probabilities were estimated using Bayes’ theorem. Results revealed as follows: (1) The mean RDs (ridges per 25 mm2) of boys and girls were not significantly different across the radial (15.89 vs. 16.19, respectively) and ulnar areas (15.84 vs. 16.00, respectively). For each sex, mean RDs in the radial and the ulnar were not statistically different. (2) The mean RDs in both sexes were greater in the left hand fingers compared to the right hand, and were statistically significant only in girls. (3) For the ulnar area, the RD of 13 or less is most likely to be of from male origin and that of 17 or more has a low probability of being of female origin. Comparing the radial area, an RD of 14 or less has a low probability of being of male origin while a weak probability of the RD of 17 or more is most likely being of female origin.

The nanoanatomical basis of sexual dimorphism in iridescent butterfly colouration

Structurally generated colours are at least as commonplace and varied components of animal signals as pigment colours, yet we know far less about the former, both in terms of the patterns and phenotypic variation and of their underlying correlates and causes. Many butterflies exhibit bright and iridescent colour signals that arise from a characteristic ‘ridge-lamellar’ scale surface nanoarchitecture. Although there are multiple axes of functional variation in these traits, few have been investigated. Here we present evidence that sexual dimorphism in the expression of a sexually homologous ridge-lamellar trait (iridescent ultraviolet) is mediated by sex differences in the density of lamellar-bearing scale ridges. This trait – ridge density – has also been causally related to iridescent signal variation in other coliadines (e.g. C. eurytheme), which suggests that it may offer a common basis to both intra- and intersexual differences in ultraviolet wing reflectance among these butterflies.

Determination of Gender Differences from Fingerprints Ridge Density in Two Northern Indian Population of Chandigarh Region

Ridge width influences the number of ridges present in a specified area of a fingerprint epidermal ridge density and several researches have been carried out on this aspect of fingerprints. The present study has been carried out to examine ridge density differences in two Northern Indian populations (Khatri and Bania). In the present study it has been found that 92% of Khatri females have a mean ridge density above 13, whereas 76% of Khatri males have (a mean ridge density) below 13, while in Bania, 100% of females have mean ridge density above 14 and 80% of males below 14. The study suggests that there are significant differences in epidermal ridge density between males and females within each of the two populations and also significant differences between the two populations. This study will provide additional information for the fingerprint examiner in analyzing finger impressions and narrowing down an investigation involving a large number of samples.

Sex differences in fingerprint ridge density in the Mataco-Mataguayo population

Ridge density (RD), the number of digital ridges per unit area, varies according to sex, age, and population origin. The main objective of this study was to determine the extent of sexual dimorphism in RD and to set the age at which it appears, in an Amerindian sample from the Mataco-Mataguayo population. The sample studied for this research consisted of 99 males and 110 females, between 6 and 25 years old, which amounts to a total of 2090 fingerprints. Ridge count was carried out on distal radial and distal ulnar and on proximal regions of each finger to explore the RD patterns in order to identify similarities and differences among samples, areas, age groups, and sexes. RD decreased with age and, at all ages, RD was higher on the distal (radial and ulnar) areas, followed by the proximal sides. Females were found to have higher RD than males when older than 12 years, but not when younger. In the radial area, the Mataco-Mataguayo population, in both sexes, presented the RD similar to Spanish samples, but higher than all other populations analysed to date using this method. Variations in RD in the Amerindian population based on sex, age, and topology were confirmed in this work, and it is postulated that these variations are due to developmental differences among individuals and populations. A comparison between the Mataco-Mataguayo and Spanish populations is presented.

Impact of Gender and Race on Fingerprint Recognition System in Egyptians Versus Malaysians

Finger prbus have been shown to be genetically determined, co11servative in their evolution, and different between and within population groups. Finger ridges and ridge patterns are highly heritable, chirable, and age-independem human traits and have been studied as a model qualltitative trait in humans for over 80 years. This study was corulucted 10 determine finger ridge count and pattern among Egyptians and Malaysian subjects in order to illicit the differences between them, as well as to determine sex impacts 0 11 both groups. Four equal groups of 100 persons each were included from Egyptian and Malaysian people of both sexes. All were healthy and within age range of ( 18-21) years old. ,BilateraL digital prints from each one were obtained by inking procedure. Ridge count per 25m.m2 is detennined together with assessment of ridge pattern rype. Statistical analysis was done with references to both sexes in both groups. Gender based variation in ridge count in both Egyptian and Malaysian subjects were detected, where males tend to have significantly lesser number of ridges compared to females. 505% ojmales werefowui to have a ridge count of J2. Beyond 12 ridges the number of males decreases rapidly and no male was found to have more tlwn I 5 ridges. On the other hatui, no fenwles were found to have 10 ridges. There was a highly statistical difference in ridge density between Egyptian arui Malaysian females, and no statistical difference between Egyptian and Malaysian males. Ridge patterns show significan.J variation among both sexes in the included groups. Ulnar loops were significantly greo.Jer in females than in males while in males whorls were significantly greater. Ulnar loops were the predomi11an.t ridge pattem among the EgyptiOJIS, while whorls were more common OJnong the Malaysians.

Gender differentiation by finger ridge count among South Indian population

The goal of this study is to determine the gender based on finger ridge count within a well-defined area. Rolled fingerprints were taken from 550 subjects (275 men and 275 women) belonging to South Indian population all within the age range of 18–65 years. Results show that women have a significantly higher ridge count than men. Application of Baye’s theorem suggests that a fingerprint possessing ridge density <13 ridges/25 mm 2 is most likely to be of male origin. Likewise, a fingerprint having ridge count >14 ridges/25 mm 2 are most likely to be of female origin. These results are helpful as a tool for fingerprint experts as they can be used as a presumptive indicator of gender based on the degree of ridge density.

Sex differences from fingerprint ridge density in Chinese and Malaysian population

The fingerprints are very typical for a human being. The present study was undertaken to study the gender differences in fingerprint ridge density in Chinese and Malaysian population. The study done on 200 subjects (100 males and 100 females) of Chinese origin and 100 subjects (50 males and 50 females) of Malaysian origin revealed that significant gender differences occur in the finger ridge density. Fingerprint mean ridge density of 12 ridges/25 mm 2 or less is found to be more likely to be of males and a mean ridge count of more the 13 ridges/25 mm 2 is more likely of female origin in Chinese subjects. Fingerprint mean ridge density of 11 ridges/25 mm 2 or less is found to be more likely to be of males and a mean ridge count of more the 13 ridges/25 mm 2 is more likely of female origin in Malaysian subjects.

Investigation of structural colors inMorphobutterflies using the nonstandard-finite-difference time-domain method: Effects of alternately stacked shelves and ridge density

We use the nonstandard-finite-difference time-domain (NS-FDTD) method to investigate the interaction of light with the complicated microstructures in the Morpho butterfly scales, which produce the well-known brilliant blue coloring. The NS-FDTD algorithm is particularly suitable to analyze such complex structures because the calculation can be performed in a short time with high accuracy on a relatively coarse numerical grid. We analyze (1) the microstructure obtained directly by binarizing an electron microgram of the cross section of a scale, (2) the reflection and diffraction properties of three model structures--flat, alternating, and tree-shaped alternating multilayers, and (3) an array of alternating multilayers with random noise superposed on the height of the structures. We found that the actual microstructure well reproduced the reflection spectrum in a blue region by integrating the reflection intensities over all the reflection angles. Under normal incidence, the flat multilayer mainly stresses on multilayer interference except for shorter wavelengths, while alternating multilayer rather enhances the effect of diffraction grating due to longitudinally repeating structure by strongly suppressing the reflection toward the normal direction. In the array of alternating multilayers, the reflection into larger angles is considerably suppressed and the spectral shape becomes different from that expected for a single alternating multilayer. This suppression mainly comes from the scattering of reflected light by adjacent structures, which is particularly prominent for the TM mode. Thus a clear difference between the TE and TM modes is observed with respect to the origin of spectral shape, though the obtained spectra are similar to each other. Finally, the polarization dependence of the reflection and the importance of the alternating multilayer are discussed.

Sex differences from fingerprint ridge density in the Indian population

Determination of individuality is one of the prime concerns in forensic investigation. The study of fingerprints is widely used in providing a clue regarding identity. The present study was undertaken to study the sex differences in fingerprint ridge density in the Indian population. The study done on 100 males and 100 females revealed that significant sex differences occur in the fingerprint ridge density. The present study shows a statistically significant difference in fingerprint ridge densities of male and female fingerprints in people of Indian origin. A mean fingerprint ridge density of 12 ridges/25 mm 2 or less is found to be more likely to be of males and a mean ridge count of more the 12 ridges/25 mm 2 is more likely to be of female origin.

Variability of fingerprint ridge density in a sample of Spanish Caucasians and its application to sex determination

Despite the fact that the differences in epidermal ridge density between men and women have been accepted for some time, they have only been thoroughly demonstrated in a small number of populations. The aim of this study is to determine whether such differences exist in a sample of the Spanish population by counting epidermal ridges within three well-defined fingerprint areas. If significant gender differences do exist, then the likelihood of inferring gender from given ridge densities will be explored. The data used in this study was obtained from all 10 fingerprints of 200 individuals of the Spanish Caucasian population (100 males and 100 females) between the ages of 20 and 30. Results show that women tend to have a significantly higher ridge density than men in the distal region of all 10 fingers (radial and ulnar count areas), but not in the proximal region (lower count area). The application of Bayes’ theorem, assuming that prior probabilities known for each sex, indicate a threshold for discrimination of sexes.

Gender Determination using Fingertip Features

Several previous studies have investigated the gender difference of the fingerprint features. However, regarding to the statistical significance of such differences, inconsistent results have been obtained. To resolve this problem and to develop a method for gender determination, this work proposes and tests three fingertip features for gender determination. Fingerprints were obtained from 115 normal healthy adults comprised of 57 male and 58 female volunteers. All persons were born in Taiwan and were of Han nationality. The age range was18-35 years. The features of this study are ridge count, ridge density, and finger size, all three of which can easily be determined by counting and calculation. Experimental results show that the tested ridge density features alone are not very effective for gender determination. However, the proposed ridge count and finger size features of left little fingers are useful, achieving a classification accuracy of 75% (P-value

The effect of heterogeneous second phase on the machinability evaluation of spheroidal graphite cast irons in the WEDM process

This paper presents an investigation about the relationships between the heterogeneous second phase and the machinability evaluation of the ferritic SG cast irons in the wire electric discharge machining (WEDM) process. The factors of second phase considered are the quantity, diameter and area fraction of spheroidal graphite particles. The experimental specimens adopted a range of 2.1–4.1 mass% to change the carbon content for clarifying the effect of graphite particles on the machinability evaluation of the ferritic SG cast irons. The machining performance evaluations performed by the experiment are the ridge density, discharge density, material removal rate (MRR) and surface roughness (SR). The conclusions reveal that the more ridge density promotes the amount of discharge density and promote the machining efficiency in the WEDM process. The formation of the ridges is closely related to the quantity and shape of graphite particles. The status of graphite particles are found to be an important factor in determining the material removal rate (MRR) and surface roughness (SR).

Sex Determination from Fingerprint Ridge Density

This study was conducted with an aim to establish a relationship between sex and fingerprint ridge density. The fingerprints were taken from 500 subjects (250 males and 250 females) in the age group of 18-60 years. After taking fingerprints, the ridges were counted in the upper portion of the radial border of each print for all ten fingers and mean value was calculated. The results have shown that a finger print ridge of < 13 ridges/25 mm2 is more likely of male origin and finger print ridge of > 14 ridges/25 mm2 is more likely of female origin. It has been successful to support the hypothesis that women tend to have a statistically significant greater ridge density than men. Keywords: Fingerprint, Ridge density, Sex, Personal identification Internet Journal of Medical Update Vol. 2 (2) 2007: pp. 1-4