Differences In Relative Length Research Articles

The lionfishes: Comparative development of Pterois volitans, Dendrochirus barberi, and D. hemprichi (Scorpaeniformes: Scorpaenidae: Pteroinae) and discrimination of their early life stages from non-pteroine scorpaenid genera in the Western North Atlantic.

Despite the threat that lionfishes pose to non-native marine ecosystems worldwide, their early life stages (ELS) remain difficult to distinguish from morphologically similar taxa due to inadequate descriptions and poorly defined taxonomic characters. Two members of the Indo-Pacific marine assemblage commonly known as lionfishes, zebrafishes, firefishes, turkeyfishes, and butterfly-cods (Scorpaeniformes: Scorpaenidae: Pteroinae) are invasive in the Western North Atlantic (WNA). Here, we describe the ELS of Pterois volitans, Dendrochirus barberi, and two transforming larvae and an early juvenile of D. hemprichi; review the early development of D. zebra and a larva described as D. bellus; identify characteristics that distinguish P. volitans from the four members of Dendrochirus; and compile meristic and distribution data for all currently valid species of lionfishes worldwide based on recent revisions and updated nomenclature. We also briefly describe a small juvenile of two poorly known non-pteroine deep-water scorpaenids, and discuss characteristics that distinguish the five pteroines from non-pteroine scorpaenid genera in the WNA. Differences in relative length and elevation of the parietal and nuchal spines, and in pigmentation patterns distinguish P. volitans from the four members of Dendrochirus. Pterois volitans has parietal spines two or more times longer than the nuchals with both sets of spines oriented about 30° above the longitudinal axis of the head, whereas the four members of Dendrochirus have relatively short parietal and nuchal spines subequal in length that lay flatter against the cranium (i.e., elevation ≤15° above longitudinal axis of head). Transforming larvae of the four members of Dendrochirus also develop saddles of pigment along the dorsal and ventral margins of the body that P. volitans lacks at the sizes examined. One or more of the following suite of traits distinguish larvae of the five pteroines from those of non-pteroine scorpaenids and other morphologically similar taxa: the presence or absence of a "shield" of pigment over the dorsolateral margin of the visceral mass (may be reduced or augmented with scattered blotches of pigment in larger larvae of some taxa); the relative length, elevation, and placement of the parietal and nuchal spines; the presence or absence of a small slit behind the fourth gill arch; differences in pectoral-fin length, shape, and extent of pigmentation; the relative size, length, and placement of spines along the posterior shelf of the preopercle (PPO); and the presence or absence, number, and placement of spine(s) along the opercle.

Interspecific variability in internal anatomy in Terebellides Sars, 1835 (Annelida, Trichobranchidae) revealed with micro-CT

The number of new species described of the genus Terebellides Sars, 1835 (Annelida, Trichobranchidae) in the eastern Atlantic Ocean has greatly increased in the last years. Eleven of these species, all originally described in NE Atlantic Ocean, from the Barents Sea to the Gulf of Guinea, have been studied using micro-computed tomography (micro-CT) thus revealing interspecific differences in several elements of the internal anatomy such as the proportion between stomach regions and size of nephridia, and in the number of lamellae in the digestive gland. Two stomach morphotypes have been distinguished regarding differences in relative length between regions, as well as two morphotypes of nephridia according to their size and wall thickness, and four types of the digestive gland regarding their number of lamellae. Differences in nephridia sizes is the only character apparently related to the geographic distribution of species (i.e. NE Atlantic vs. Gulf of Guinea) but examination of more taxa is needed. A third distinct region was distinguished in the stomach, named here as mid stomach, that differs from the fore and hind stomach in epithelia thickness and by lacking connective muscular sheath. The potential of the micro-CT technique in the search for internal anatomical characters with taxonomic value is discussed.

Interpreting alignment-free sequence comparison: what makes a score a good score?

Alignment-free methods are alternatives to alignment-based methods when searching sequence data sets. The output from an alignment-free sequence comparison is a similarity score, the interpretation of which is not straightforward. We propose objective functions to interpret and calibrate outputs from alignment-free searches, noting that different objective functions are necessary for different biological contexts. This leads to advantages: visualising and comparing score distributions, including those from true positives, may be a relatively simple method to gain insight into the performance of different metrics. Using an empirical approach with both DNA and protein sequences, we characterise different similarity score distributions generated under different parameters. In particular, we demonstrate how sequence length can affect the scores. We show that scores of true positive sequence pairs may correlate significantly with their mean length; and even if the correlation is weak, the relative difference in length of the sequence pair may significantly reduce the effectiveness of alignment-free metrics. Importantly, we show how objective functions can be used with test data to accurately estimate the probability of true positives. This can significantly increase the utility of alignment-free approaches. Finally, we have developed a general-purpose software tool called KAST for use in high-throughput workflows on Linux clusters.

Biomechanics as driver of aggregation of tethers in adherent membranes.

Cell adhesion is an important cellular process and is mediated by adhesion proteins residing on the cell membrane. Sometimes, two types of linker proteins are involved in adhesion, and they can segregate to form domains through a poorly understood size-exclusion process. We present an experimental and theoretical study of adhesion via linkers of two different sizes, realised in a mimetic model-system, based on giant unilamellar vesicles interacting with supported lipid bilayers. Here, adhesion is mediated by DNA linkers with two different lengths, but with the same binding enthalpy. We study the organisation of these linkers into domains as a function of relative fraction of long and short DNA constructs. Experimentally, we find that, irrespective of the composition, the adhesion domains are uniform with coexisting DNA bridge types, despite their relative difference in length of 9 nm. However, simulations suggest formation of nanodomains of the minority fraction at short length scales, which is below the optical resolution of the microscope. The nano-aggregation is more significant for long bridges, which are also more stable.

Cytogenetic Diversity and Characterization of Vicia sativa Subspecies

Background: Vicia sativa L. is variable genus comprised of several subspecies. Close relative species and subspecies of the cultivated species are easily usable gene sources because they have gained resistance against a wide range of biotic and abiotic stresses. The main objectives of this study are to identify and describe the cytogenetical and karyological characteristics of subspecies in the Vicia sativa complex.Methods: The research material consisted of multiple entries collected from the five subspecies of nine taxa. All cytological observations made from root tips. Six chromosomal parameters (chromosome length, relative length, long arm length, short arm length, arm ratio and centromeric index) and five karyotype asymmetric parameters (difference in relative length, total form percentage, intrachromosomal asymmetry index, interchromosomal asymmetry index and mean centromeric asymmetry) were determined.Result: It was determined that the chromosome number of subspecies were 2n =10-12. The haploid chromosome lengths of subspecies were 15.86-33.88 µm and the average chromosome lengths varied between 2.64-5.65 µm. According to the intrachromosomal karyotype asymmetry index analysis, subsp. segetalis was the most asymmetric karyotype and subsp. sativa “Antalya” was the most symmetric karyotype. According to the interchromosomal karyotype asymmetry index analysis, subsp. angustifolia was the most asymmetric karyotype and subsp. nigra was the most symmetric karyotype.

Well-founded practice or personal preference: a comparison of established techniques for measuring ulnar variance in healthy children and adolescents

ObjectivesUlnar variance is a clinical measure used to determine the relative difference in length between the radius and ulna. We aimed to examine consistency in ulnar variance measurements and normative data in children and adolescents using the perpendicular and the Hafner methods.MethodsTwo raters measured ulnar variance on hand radiographs of 350 healthy children. Participants’ mean calendar and skeletal ages were 12.3 ± 3.6 and 12.0 ± 3.7 years, 52% were female. Raters used the perpendicular method, an adapted version of the perpendicular method (in which the distal radial articular surface is defined as a sclerotic rim) and the Hafner method, being the distance between the most proximal points of the ulnar and radial metaphyses (PRPR) and the distance between the most distal points of both (DIDI). Intraclass correlation coefficients (ICCs) for intermethod consistency and inter- and intrarater agreement were calculated using a two-way ANOVA model. Variability and limits of agreement were determined using the Bland-Altman method.ResultsThe interrater ICC was 0.75 (95% CI, 0.61–0.84) for the adapted perpendicular method, 0.88 (95% CI, 0.80–0.93) for PRPR, and 0.94 (95% CI, 0.90–0.97) for DIDI. The intermethod consistency ICC was 0.60 (95% CI, 0.48–0.70) for perpendicular versus PRPR and 0.60 (95% CI, 0.49–0.70) for perpendicular versus DIDI. The intrarater ICC was 0.88 (95% CI, 0.70–0.95) for perpendicular, 0.90 (95% CI, 0.83–0.94) for PRPR, and 0.81 (95% CI, 0.69–0.89) for DIDI. The perpendicular method was not useable in 38 cases (skeletal age ≤ 9 years) and the Hafner method in 79 cases (skeletal age ≥ 12 years).ConclusionsThe perpendicular and Hafner methods show moderate intermethod consistency. The Hafner method is preferred for children with skeletal ages < 14 years, with good to excellent inter- and intrarater agreement. The adapted perpendicular method is recommended for patients with skeletal ages ≥ 14 years.Key Points• The perpendicular method for measuring ulnar variance requires extended instructions to ensure good interrater agreement in pediatric and adolescent patients.• The Hafner method is recommended for ulnar variance measurement in children with unfused growth plates and up to a skeletal age of 13 years, and the perpendicular method is recommended for children with fused growth plates and from skeletal age 14 and older.• The mean ulnar variance measured in this study for each skeletal age group (range, 5–18 years) is provided, to serve as a reference for future ulnar variance measurements using both methods in clinical practice.

A simple, effective, universal, and reusable osteotomy tool for jaw reconstructions with microvascular fibula transplants

Precise, expensive individual saw guides are used with increasing frequency for the reconstruction of mandibular defects with fibular grafts. In this report, an alternative is presented - the Multiuse Cutting Jig (MUC-Jig, proprietary development). It is reusable, suitable for all patients, requires simple planning based on conventional CT imaging, and is more economical. To investigate its precision, we conducted a nonblinded experimental study, with ten participating craniomaxillofacial surgeons. Osteotomies of four different fibula segments were carried out at the same angulation, with groups defined according to the proximal and distal fixed angulation: 45°, 30°, 15°, or 0°. The sagittal cut was performed proximally, with the coronal cut performed distally. The resulting 40 segments (n = 40) were analyzed with their Tx length (primary endpoint) and osteotomy angles, and compared to the original planning. The mean (SD) relative deviation of all grafts from the original planning was -0.08 mm (1.12) in length and -0.71° (3.15) for the angle. Only 45° (-2.04 ± 3.71°) and 30° (-1.07 ± 2.52°) cuts differed significantly (p < 0.05) from smaller angle grafts. The mean (SD) absolute deviation was 0.81 mm (0.27) in length and 2.13° (0.93) in graft angles. For individual transplants, 45° cuts (1.28 ± 1.03 mm) differed significantly (p < 0.005) from others. We observed no differences in relative length or absolute angle deviation. The MUC-Jig is precise and cost-effective for osteotomies with medium angles and smooth reconstructions of template-guided procedures.

Comparison of frequency and severity of longitudinal stent deformation among various drug-eluting stents: An intravascular ultrasound study

BackgroundLongitudinal stent deformation (LSD) in drug-eluting stents (DES) has been described as a disruption of stent structure. This study aimed to compare first- versus second-generation DES with respect to their actual stent length post deployment. MethodsA total of 617 DES for de novo coronary lesions in 552 patients were analyzed. Intravascular ultrasound (IVUS) was utilized to compare the degree and rate of LSD among six different DES types. IVUS-measured stent length was compared to the labeled length for calculation of absolute difference in stent length and relative absolute difference (absolute difference divided by the labeled length). ResultsThe baseline characteristics were comparable between groups, except for higher calcification in the sirolimus-eluting stent (SES) group (p=0.037). The absolute and relative difference in length showed the lowest degree in the SES group and the highest degree in the Endeavor zotarolimus-eluting stent group (p=0.085 and 0.078, respectively). The percentage of more than 5% relative absolute difference was the lowest in the SES group compared to the other groups (p=0.018). However, the percentage of significant (>15%) relative absolute difference was similar among groups (p=0.99). In multivariate linear regression analysis, labeled stent length and stent diameter, but not stent type, were identified as independent correlates to the absolute and relative difference in the actual stent length post-deployment. ConclusionThis IVUS analysis confirms that among second-generation DES, there is overall similar frequency and severity of LSD when deploying in common coronary lesions.

Comparison of stent axial integrity in first- versus second-generation drug-eluting stents: insights from intravascular ultrasound analysis

Background: Longitudinal stent deformation (LSD) is a recently reported complication of coronary intervention. To date, however, the axial integrity of stents has not been systematically examined. This study aimed to assess the rate of LSD after implantation using intravascular ultrasound (IVUS). Methods: A total of 182 drug-eluting stents (DES) of 165 patients who underwent IVUS after implantation for de-novo lesions were included. Stent length was determined using automatic pullback device. The absolute value of the difference in length [IVUS - label], and the absolute value of the relative difference in length [(IVUS- label)/label] were analyzed. Results: Stent distribution was as follows: 38.4% sirolimus-eluting stents (SES); 18.7% paclitaxel-eluting stents (PES); 20.3% Cobalt-chromium everolimus-eluting stents (Cc-EES); and 22.5% Platinum-chromium everolimus-eluting stents (Pc-EES). The absolute difference in length did not differ among groups. There were no differences in the absolute value of the relative difference between the Pc-EES and any other stents. The absolute relative difference of >5% was lower in the SES group (p=0.027). Significant change (>15%) in length was low and similar among groups. ![Figure][1] Conclusions: This IVUS analysis proved that SES has the lowest differences in stent length and that there are no significant differences in axial stent integrity among PES and second-generation DES. The anecdotal reports of LSD are unsubstantiated in contemporary clinical practice. [1]: pending:yes

Population diversity and analysis of cytogenetic affinities between different Silybum marianum L. populations from Iran

Cytogenetic diversity on ten different Silybum marianum populations was evaluated in this study by using karyotype decomposition technique. The obtained results from karyologic studies of root tip samples showed that the base number of chromosomes was x = 17 in all the considered populations and the number of chromosomes were 2n = 2x = 34. Regarding the ploidy level, all the populations were diploid. According to Stebbin’s classification of karytype symmetry, all the populations were placed in “2B” category, indicating the similar evolutionary situations of the populations. The obtained results from the variance analysis of the resulted data from measuring the characteristics showed that there is a significant difference; as for the probability of 0.1, between the populations, regarding the total chromosome lengths (TL), sum of long arms (Sla), coefficient of variability of centromic index (CVci) and the asymmetric index (AI) and there is a significant difference (p < 0.05) regarding the longest and shortest chromosomes (LC, SC), sum of short arms (SSa), difference in relative lengths (DRL) and the ratio of long to short arms (AR). This indicated the diversity in the size and symmetry of chromosomes among the considered populations. Factor analysis provided three factors that justified nearly 96 % of the total variations between the populations, such that in the first factor, the difference in the relative length and the total chromosome length had the greatest role in creating variations in the populations by having the highest specific vector coefficients. For the 2nd factor, the asymmetric index and variation coefficient of centromic index had a great importance for the variance between the populations. For the 3rd factor, the relative length difference had the most important role in establishing this factor. Cluster analysis with dendrogram sectioning at the distance of 10.59 categorized populations in 4 groups. The least Euclidean distance was observed between the populations in Ahvaz and Sari and the most Euclidean distance was between the populations of Ahvaz and Rasht. The results from cluster variances analyses showed that all the characteristics, apart from DRL had significant diversity between the groups. Regarding the characteristics related to genome length, the populations of Ahvaz, Sari and Esfahan had the highest amounts and Kurdestan population in the 4th group had the highest value regarding AI, CVci and AR characteristics.

Chromosome numbers are not fixed in Agaonidae (Hymenoptera: Chalcidoidea)

Agaonidae (the pollinators of fig trees, Ficus spp., Moraceae) are a distinctive family of chalcid wasps with uncertain affinities within the Chalcidoidea. Chromosome numbers have only been described previously for one species (Blastophaga psenes, 2n = 12, the pollinator of F. carica, of subgenus Ficus). In this paper, we used a modified technique to analyze the karyology of three Ceratosolen species, Ceratosolen solmsi, C. graveli and C. emarginatus which are associated with figs of Ficus subgenus Sycomorus. Their karyotypes are 2n = 10. All the chromosomes are metacentric (NF = 20) with little difference in relative lengths, making them hard to distinguish. The variation in chromosome numbers that we have detected suggests that karyology can usefully complement molecular-based studies of the phylogeny of fig wasps.

Atomistic Simulation Study of Striped Phase Separation in Mixed-Ligand Self-Assembled Monolayer Coated Nanoparticles

Atomistic molecular dynamics simulations are performed to study the stripelike patterns formed by phase separation of immiscible surfactants grafted on spherical surfaces. In previous work (Phys. Rev. Lett. 2007, 99, 226106), we showed that the formation of a striped phase for a mixture of two different length surfactants does not depend on the detailed chemistry of the molecules. Rather, the pattern is stabilized by increased conformational entropy related to the geometry of the molecules. In this paper, we extend the atomistic simulations of our earlier study to investigate the dependence of stripe thickness on charges on the head groups, the relative length difference of the tail, and the strength of the repulsion between the surfactants. Previously, we studied the dependence of the tilt angle for a homoligand surfactant on a nanoparticle surface (J. Phys. Chem. C 2007, 111, 15857). Here, we study the dependence of the tilt angle for mixed-ligand surfactants on a spherical nanoparticle surface. We obse...

Automatic Segmentation of Calcifications in Intravascular Ultrasound Images Using Snakes and the Contourlet Transform

It is valuable to detect calcifications in intravascular ultrasound images for studies of coronary artery diseases. An image segmentation method based on snakes and the Contourlet transform is proposed to automatically and accurately detect calcifications. With the Contourlet transform, an original image is decomposed into low-pass bands and band-pass directional sub-bands. The 2-D Renyi's entropy is used to adaptively threshold the low-pass bands in a multiresolution hierarchy to determine regions-of-interest (ROIs). Then a mean intensity ratio, reflecting acoustic shadowing, is presented to classify calcifications from noncalcifications and obtain initial contours of calcifications. The anisotropic diffusion is used in bandpass directional sub-bands to suppress noise and preserve calcific edges. Finally, the contour deformation in the boundary vector field is used to obtain final contours of calcifications. The method was evaluated via 60 simulated images and 86 in vivo images. It outperformed a recently proposed method, the Santos Filho method, by 2.76% and 14.53%, in terms of the sensitivity and specificity of calcification detection, respectively. The area under the receiver operating characteristic curve increased by 0.041. The relative mean distance error, relative difference degree, relative arc difference, relative thickness difference and relative length difference were reduced by 5.73%, 19.79%, 11.62%, 12.06% and 20.51%, respectively. These results reveal that the proposed method can automatically and accurately detect calcifications and delineate their boundaries. (E-mail: yywang@fudan.edu.cn)

Delineation and Distribution of Zephyranthes Species (amaryllidaceae) Endemic to the Southeastern United States

ABSTRACT Three closely related, midwinter to spring-flowering, mesic species of Zephyranthes (Amaryllidaceae) are endemic to the southeastern United States: Z. atamasca, Z. treatiae, and Z. simpsonii. The taxonomic level of the distinctiveness of Z. treatiae from Z. atamasca is discussed. Based on herbarium, cytological, and field studies, and on Principal Component Analysis and pictorialized scatter diagram analysis, we conclude that all three taxa are distinct at the species level. They are distinguished by differences in relative lengths of floral elements. Illustrations, a distribution map, and a key are provided.

The Influence of Second Toe and Metatarsal Length on Stress Fractures at the Base of the Second Metatarsal in Classical Dancers

Stress fractures at the base of the second metatarsal frequently occur in female classical dancers. There is a strong belief that a foot shape in which the first metatarsal or toe is shorter than the second metatarsal or toe increases the risk of this injury in dancers. However, there is a lack of empirical evidence to support this theory. The objective of this study was to examine the influence of the relative length difference between the first and second metatarsals and first and second toes on the frequency of stress fractures at the base of the second metatarsal in elite, female classical dancers. Both feet of 50 elite female classical dancers were measured for length differences between the first and second toes and first and second metatarsals. Retrospective analysis of dancers' medical histories revealed 17 feet with stress injury and 83 without. The mean of the difference between the metatarsal and toe length for the stress-injury group was compared to that of the control group. No difference between the groups was identified for first and second toe length difference (p = 0.865) and the relative difference between the ends of the first two metatarsals (p = 0.815). Dancers who had a stress injury at the base of the second metatarsal displayed similar variances in the two independent variables as dancers who had not had such an injury.

Automated neurite labeling and analysis in fluorescence microscopy images

To investigate the intricate nervous processes involved in many biological activities by computerized image analysis, accurate and reproducible labeling and measurement of neurites are prerequisite. We have developed an automated neurite analysis method to assist this task. Our approach can be considered as automated with certain user interaction in setting initial parameters. Single and connected centerlines along neurites are extracted. The computerized method can also generate branching and end points. Owing to its multi-scale flexibility, both thick and thin neurites are simultaneously detected. We employ the relative neurite length difference (defined as the difference between the lengths obtained by automated and manual analysis divided by the total length of the latter) and neurite centerline deviation (defined as the area of the regions enclosed by different paths between automated and manual analysis divided by the total length of the former) to evaluate the performance of our algorithm, which is of great interest in neurite analysis. The average of the relative length difference is about 0.02, while the average of the centerline deviation is about 2.8 pixels. The probabilities of the distributions being the same from the Kolmogorov-Smirnov (KS) test of the automatic and manual results are 99.79%. The KS test also shows no significant bias between different observers based on the proposed new validation scheme. With the accurate and automated extraction of neurite centerlines and measurement of neurite lengths, the proposed method, which greatly reduces human labor and improves efficiency, can serve as a candidate tool for large-scale neurite analysis beyond the capability of manual tracing methods.

Estimating the patient care costs of teaching in a teaching hospital

Purpose Because leaders at medical schools and teaching hospitals need current data to estimate the clinical costs of graduate medical education, the authors developed a new methodology to estimate the hospital costs associated with the presence of teaching physicians for the year 2002. Method A hospital accounting system was used to determine the case mix-adjusted direct variable costs for 41 522 inpatient admissions associated with or without a teaching physician. Results Prior to adjustment, teaching cases had greater median costs than non-teaching cases. After severity adjustment, teaching cases in aggregate were associated with an additional 4.4% of the total direct variable cost of inpatient admissions, or $3.6 million. The size of the teaching effect varied by service, ranging from −5.7% for medical services to 13 percent for behavioral services. The effect of teaching on cost centers such as laboratory, pharmacy, and radiology varied by specialty service. Teaching was associated with a negligible 0.7% relative difference in length of stay. Conclusion The incremental effects of teaching on hospital patient care costs are modest. These analyses can be repeated annually to detect changes in teaching costs and to target areas of excessive cost for interventions that improve efficiency. Our results and methods for identifying hospital costs associated with teaching services may prove useful in negotiations between academic health centers and affiliated teaching hospitals.

Sex dimorphism in digital formulae of children

This paper presents results of a study designed to: 1) test for a sex difference in the relative lengths of the finger bones, including the second-to-fourth digit ratio (2D:4D), using left-hand radiographs taken in young children, 2) test whether sex differences can be explained by sex differences in fetal growth, and 3) test the serial stability of sex differences in relative digit lengths, including 2D:4D. Results are presented from 1,060 subjects of the California Child Health and Development Studies. One serial replication at about 9 years old is available from 271 subjects. Results indicate that relative digit lengths are sex-dimorphic in children (Manning et al. [1998] Hum. Reprod. 13:3000-3004, [2004] Early Hum. Dev. 80:161-168). Sex differences in digit length ratios are more pronounced within sibships, where shared family factors are controlled, and are not strongly associated with gross measures of fetal growth, like birth length or weight. Thus, sex differences in the fetal growth of the body are not implicated in sex differences in digital formulae, leaving open the possibility of more direct hormonal and/or genetic causation. However, 2D:4D declined between ages 6-8 in a longitudinal sample, and was a less consistent sex-dimorphic marker than 3D:4D across ethnic groups, suggesting that 3D:4D may be a better marker of perinatal sex differentiation. Prior conflicting findings about 2D:4D may be partly explained by variations in age and ethnicity of populations studied.

The relative lengths and weights of metacarpals and metatarsals in baboons ( papio hamadryas)

The lengths and weights of metacarpals and metatarsals were measured in two collections of baboon skeletons—33 animals, all born and raised in the wild, and 60 animals, nearly all born and raised in captivity. For both length and weight, ratios were constructed for all possible pairings of the five bones in each individual hand and foot. The pattern of results was not identical for the two collections, but substantial sex differences existed in both collections for many of the ratios calculated. Nearly all of the large sex differences were in the direction of the length or weight ratio being smaller for males than for females. For the length ratios showing the largest sex differences, those differences were larger for the right hand than for the left, and larger for the left foot than for the right, but this pattern was less evident for the weight ratios. Some length ratios for human fingers show sex differences of the sort seen in the metacarpals and metatarsals of these baboons, and the human differences in relative length exist early in life. The implication is that the marked sex difference in androgen exposure during prenatal development may effect the relative size of the individual bones of the extremities in male and female humans and baboons. The relative sizes of the bones of the hand and foot may provide helpful supplemental information on the relations between species, thus making the study of hand and foot bones in other primates and mammals worthwhile.

Effects of rearing density, size grading and parental factors on sex ratios of the sea bass (Dicentrarchus labrax L.) in intensive aquaculture

Abstract The effects of rearing density and size grading on sex ratios in 30 families of sea bass reared in the same tank from the fertilization stage onwards were investigated. Two extreme density treatments (high versus low) were applied in quadruplicates throughout the labile period for sex determination. An excess of males (88%) was found in all groups. Growth was faster under low density from 49 to 191 days post fertilization (p.f.) (27–10% relative difference in length) and was then equivalent between the two groups until the end of the treatments (414 days p.f.). Density had no effect on sex ratio, suggesting that the high densities usually applied in aquaculture are not involved in the systematic excess of males reported in farmed populations. The fish were genotyped at three to six microsatellite loci. This allowed them to be assigned to the individual breeders used in the mating design. The percentage of females was significantly influenced by both the dam and the sire, highlighting the existence of genetic variation of sex ratio. Repeated size grading performed from 84 to 199 days p.f. had no effect on the sex ratio of the overall population studied showing that sex determination had not been affected by the treatment. However, the highest percentages of females were found in the lead classes from 84 days p.f. Most of the fish in this lead group were descended from one dam and the percentage of females found in the individual families were higher in this class than in the non-graded group. These results show that females start growing faster than males long before morphological sexual differentiation occurs.