Head Length Measurements Research Articles

Condition, Reproductive Fitness, and Fluctuating Asymmetry in Brook Stickleback: Responses to Anthropogenic Runoff

Multiple indicators have been used to assess the degree of exposure of fish to anthropogenic chemicals in their stream habitats. We hypothesized that brook stickleback (Culaea inconstans) in a headwater stream receiving urban and agricultural runoff (South Fork Whitewater River, SFWR) would exhibit poorer condition, reduced reproductive fitness, and a greater left side to right side morphological asymmetry (i.e., fluctuating asymmetry or FA) than fish from a nearby headwater stream with a forested drainage basin (Garvin Brook). Male and female fish were collected from both streams just prior to spawning in 2013–2015. In 2013 and 2014, fish were assessed for overall condition (Fulton’s K), internal measures of condition (hepatosomatic index, HSI) and reproductive fitness (gonadosomatic index [GSI], total oocyte count, and oocyte mass). In 2015, measurements of head length, jaw length, eye diameter, pectoral fin length, and pelvic fin length were made on both sides of each fish for assessing degree of FA. We observed declining condition with fish size, increased liver size, and reduced oocyte counts and oocyte size in female brook stickleback in SFWR relative to those from Garvin Brook. SFWR females had significantly higher FA than Garvin females for all structures assessed, except pelvic fin length. FA also was slightly higher for all structures in SFWR males compared to Garvin males, but differences were not significant. A composite FA index combining all measurements from an individual fish into a single value displayed highly significant differences for female fish (SFWR FA >> Garvin FA), but not for male fish (SFWR FA = Garvin FA). Exposure of brook stickleback to reduced water quality in SFWR during early development appears to increase morphological asymmetry in female (but not male) fish, and continuing exposure to compromised water quality throughout life impacts both general condition and reproductive fitness of stickleback, especially older female fish, in SFWR.

Volumetric measurements of paranasal sinuses and examination of sinonasal communication in healthy Shetland ponies: anatomical and morphometric characteristics using computed tomography

BackgroundDespite clinical importance and frequent occurrence of sinus disease, little is known about the size of paranasal sinuses and their communication in ponies and small horses. To examine the shape and volume of the paranasal sinuses and evaluate the sinonasal communication, three-dimensional (3D) reconstructions of computed tomography (CT) datasets of 12 healthy adult Shetland ponies were performed and analysed. Linear measurements of head length and width were taken. Using semi-automatic segmentation, 3D-models of all sinus compartments were created. Volumetric measurement of the seven sinus compartments were conducted and statistical analysis was performed. Sinus volumes were compared between the left and right sinuses and the relation to age and head size was evaluated.ResultsStructure and shape of the paranasal sinus system in Shetland ponies was similar to that of large horses. All seven sinus compartments on each side of the head were identified (rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, middle conchal sinus, frontal sinus, sphenopalatine sinus). The existence of a bilateral cranial and a caudal system formed by a maxillary septum was visible in all 12 individuals. The volumetric sizes of the left and right sinuses did not differ significantly (p > 0.05). A positive correlation between the size of the paranasal sinuses and the head length was shown. A relation between sinus volumes and age could not be proved in adult ponies aged > six years. Communication between single sinus compartments was identified. Furthermore, communication with the nasal cavity over the nasomaxillary aperture (Apertura nasomaxillaris) and a common sinonasal channel (Canalis sinunasalis communis) as well as its splitting up into a rostral and a caudolateral channel could be seen. Examination of the sinonasal communication was challenging and only a descriptive evaluation was possible.ConclusionsOur findings concerning the size, shape and volumetric dimensions of Shetland pony CT images could help improve CT interpretation of abnormal clinical cases as well as aiding clinicians to develop and select appropriate instruments for medical inspection and treatments.

Three-Dimensional Calvarial Growth in Spring-Assisted Cranioplasty for Correction of Sagittal Synostosis.

Spring-assisted cranioplasty (SAC) is a minimally invasive technique for treating sagittal synostosis in young infants. Yet, follow-up data on cranial growth in patients who have undergone SAC are lacking. This project aimed to understand how the cranial shape develops during the postoperative period, from spring insertion to removal. 3D head scans of 30 consecutive infants undergoing SAC for sagittal synostosis were acquired using a handheld scanner pre-operatively, immediately postoperatively, at follow-up and at spring removal; 3D scans of 41 age-matched control subjects were also acquired. Measurements of head length, width, height, circumference, and volume were taken for all subjects; cephalic index (CI) was calculated. Statistical shape modeling was used to compute 3D average head models of sagittal patients at the different time points. SAC was performed at a mean age of 5.2 months (range 3.3-8.0) and springs were removed 4.3 months later. CI increased significantly (P < 0.001) from pre-op (69.5% ± 2.8%) to spring removal (74.4% ± 3.9%), mainly due to the widening of head width, which became as wide as for age-matched controls; however, the CI of controls was not reached (82.3% ± 6.8%). The springs did not constrain volume changes and allowed for natural growth. Population mean shapes showed that the bony prominences seen at the sites of spring engagement settle over time, and that springs affect the overall 3D head shape of the skull. In conclusion, results reaffirmed the effectiveness of SAC as a treatment method for nonsyndromic single suture sagittal synostosis.

Morphometric characteristics of craniofacial features in patients with schizophrenia

Background: High incidence of craniofacial dysmorphology in patients with schizophrenia confirms the developmental disruptions during embryonic period. Anthropometry of head and face can give us several clues regarding the maldevelopment of brain. The aim of this study was to assess various dimensions of skull in Schizophrenics. Methods: One hundred and one (101) male and female patients that have been diagnosed with chronic schizophrenia were selected from a psychiatric hospital and 101 healthy controls, which were mostly the paramedical staff of another hospital, were included in the study. The age for both the groups was between 20 to 60 years. The head length, width and height and coronal, axial and sagittal arc lengths, and also body height and weight and BMI of participants were measured. Results: Mean anthropometric measurements of head length, width and height were 18.92, 14.08 and 12.69 in patients and 18.90, 13.89 and 13.38 centimeter in control, also axial, coronal and sagittal arc lengths were 55.85, 35.21 and 33.00 in patients and 55.70, 34.54 and 32.19 centimeter in control group, respectively. Compared to controls the patients had significantly increased coronal (P< 0.022) and Sagittal (P< 0.001) arc lengths. The patients also showed significantly lesser head height (P< 0.001) as compared with controls. Conclusion: The linear measurements of skull in patients with Schizophrenia do not significantly differ from normal populations and/or have slightly differences. Future studies may investigate whether head can be an anatomical marker for patients with schizophrenia.

Relationships between morphometric variables and age for captive individuals may not accurately estimate the age of free-ranging juvenile koalas (Phascolarctos cinereus)

Several studies report methods for determining the age of juvenile Queensland koalas (Phascolarctos cinereus adustus) but these are mostly based on data from captive populations, because observing the birth of koalas in their natural habitat is extremely rare. We identified the exact date of birth for two male joeys by initially observing one within minutes and the other within hours of their birth, at St Bees Island, central Queensland. Successive measurements of head length, as these individuals matured, were used to construct a growth curve for free-ranging juveniles. When tested, only one previously published growth curve (based on body mass) was able to accurately estimate the age of the two joeys. Both methods were then tested for precision using morphometric data for other juvenile koalas in the St Bees population. The estimation of age of juvenile koalas was considerably more precise when based on head length. These results demonstrate the inaccuracy that may be inherent in growth curves derived from captive animals and also show that estimates of age based on data from individuals in a particular population or locality may not be accurate throughout the range of a species.

Predicting Walleye Total Length from Head and Mandible Measurements

AbstractTo supplement harvest information on walleye Sander vitreus collected in Lake Erie creel surveys, we assessed whether walleye size structure and growth could be estimated by using total lengths (TL) predicted from measurements of head length (HL) and mandible length (ML). Regression models were developed by using measurements taken from 124 tournament‐caught walleyes sampled in late May 2003. In most cases, HL and ML explained more than 90% of the variation in TL (r2 &gt; 0.90); however, residuals (absolute values) were frequently 10 mm or more. Despite estimation errors, the length‐frequency distributions predicted from HL and ML models were not significantly different from observed distributions. Tests of the models with an additional 72 walleyes collected in June 2003 produced similar results. Predicted mean lengths at age for June walleyes ages 2–4 did not differ significantly from mean lengths at age estimated from observed TL. Use of an HL model developed for Minnesota walleyes yielded results similar to those of the Lake Erie models, suggesting that development of population‐specific models may not be necessary. Given the accuracy and ease of measurement, we suggest that HL be used to predict walleye TL rather than ML; however, prediction errors indicate that age–length keys constructed by using TL predicted from HL should be validated before use.

Instar-specific head and body lengths of Hyalella (Amphipoda): criteria for starting and endpoints in experimental studies

Abstract Instar-specific data on head length and body length of Hyalella azteca was obtained from live specimens reared individually at 23 ± 1 °C under a 14L:10D photoperiod and with food ad lib. Both head length and body length were strong predictors of instar number through instars 1 – 10. The relationship between instar number and head length was linear (head length [μm] = 104.28 + 61.05[instar]; r2=0.98, P<0.001), whereas that between instar and body length was not (body length [μm] = 1339.28 + 55.82[instar]2; r2 = 0.97 , P< 0.001). Head length measurements were easier to obtain and were more accurate than body measurements. Both measurements can be obtained without injury to the animal, permitting repeated observations on the same individual.

Regression equations between body and head measurements in the broad-snouted Caiman (Caiman latirostris).

In the present study, regression equations between body and head length measurements for the broad-snouted caiman (Caiman latirostris) are presented. Age and sex are discussed as sources of variation for allometric models. Four body-length, fourteen head-length, and ten ratio variables were taken from wild and captive animals. With the exception of body mass, log-transformation did not improve the regression equations. Besides helping to estimate body-size from head dimensions, the regression equations stressed skull shape changes during the ontogenetic process. All age-dependent variables are also size-dependent (and consequently dependent on growth rate), which is possibly related to the difficulty in predicting age of crocodilians based on single variable growth curves. Sexual dimorphism was detected in the allometric growth of cranium but not in the mandible, which may be evolutionarily related to the visual recognition of gender when individuals exhibit only the top of their heads above the surface of the water, a usual crocodilian behavior.

A morphometric study of early ovarian development in pouch young of the brushtail possum (Trichosurus vulpecula)

Background Although the pattern of gonadal differentiation in marsupials is well documented, there is little information available on germ cell initiation and development. Furthermore, neither parameter has been well described for the brushtail possum (Trichosurus vulpecula). Methods A quantitative study of ovarian germ cell proliferation and the onset of folliculogenesis was undertaken in pouch young of the brushtail possum. Pouch-young age was estimated from measurements of head length and crown-rump length. Estimates of total ovary volume, the number of primary and meiotic germ cells, and the numbers of primordial follicles were made by using Cavalieri's principle and the optical disector. In addition, the age at which follicle growth began was determined. Results The estimated ages of the pouch young in the study ranged from 26 to 207 days postpartum. Body weight, ovary weight, and ovary volume were all highly correlated with estimated age. Germ cell meiotic activity was well established by day (d) 26 of pouch life. Germ cell numbers reached a maximum (691 × 103/ovary) at d67 postpartum and then declined with increasing age. Primordial follicles were first evident at d67. Primary follicles were first seen at d97, secondary follicles at d105, and antral follicles at d155. Conclusions This first quantitative study of ovarian follicle development in the female pouch young of the brushtail possum provides a basis for the temporal definition of ovarian maturation in this marsupial species. The pattern of germ cell proliferation and development is similar to that seen in eutharian mammals. © 1996 Wiley-Liss, Inc.

A morphometric study of early ovarian development in pouch young of the brushtail possum (Trichosurus vulpecula)

Although the pattern of gonadal differentiation in marsupials is well documented, there is little information available on germ cell initiation and development. Furthermore, neither parameter has been well described for the brushtail possum (Trichosurus vulpecula). A quantitative study of ovarian germ cell proliferation and the onset of folliculogenesis was undertaken in pouch young of the brushtail possum. Pouch-young age was estimated from measurements of head length and crown-rump length. Estimates of total ovary volume, the number of primary and meiotic germ cells, and the numbers of primordial follicles were made by using Cavalieri's principle and the optical disector. In addition, the age at which follicle growth began was determined. The estimated ages of the pouch young in the study ranged from 26 to 207 days postpartum. Body weight, ovary weight, and ovary volume were all highly correlated with estimated age. Germ cell meiotic activity was well established by day (d) 26 of pouch life. Germ cell numbers reached a maximum (691 x 10(3)/ovary) at d67 postpartum and then declined with increasing age. Primordial follicles were first evident at d67. Primary follicles were first seen at d97, secondary follicles at d105, and antral follicles at d155. This first quantitative study of ovarian follicle development in the female pouch young of the brushtail possum provides a basis for the temporal definition of ovarian maturation in this marsupial species. The pattern of germ cell proliferation and development is similar to that seen in eutharian mammals.

Influence of Food Type on the Growth of a Riverine Amphipod,Gammarus fasciatus

A laboratory experiment and natural-diet study were conducted to examine the feeding ecology and importance of food type for growth of Gammarus fasciatus from the Ohio River. To determine effects on growth, amphipods were fed four diets: (1) filamentous algae (Cladophora) and diatoms, (2) dead animal matter (chironomids), (3) coarse particulate organic matter (CPOM), and (4) fine particulate organic matter (FPOM). Organic matter was obtained by shredding preconditioned sycamore leaves (Platanus occidentalis). Growth was evaluated from weekly measurements of head length. There were no significant differences in growth among food types before week 3 of the experiment, but from week 4 to week 6, amphipods fed algae and dead animal matter were significantly larger than those maintained on CPOM and FPOM. Gut analysis of natural populations showed that G. fasciatus consumed all food types used in the laboratory study. The weighted proportions of filamentous algae and animal matter in riverine populations increased consistently from smallest to largest size-class. The availability of, and ability to use, algae and animal matter by G. fasciatus benefits natural populations in large rivers by enabling them to exploit seasonal changes in the relative abundance of different food sources.

Nonparametric Estimation of a Ratio of Multivariate Means and Applications

Utilizing the work of Puri and Sen in multivariate nonparametric theory, this paper describes methods for obtaining nonparametric point and interval estimates for a common ratio, say α, which exists between certain elements of the mean vector of a multivariate population. These are then applied to estimate α on the basis of measurements of head length and head breadth of pairs of brothers and growth of pairs of plants. Some advantages of the nonparametric method are explained.

Body condition and population regulation by food resources in moose.

In southwestern Québec, non-harvested moose populations stabilize at a density of ≈0.40 animal·km-2. In an attempt to test population regulation by food resources, we investigated moose body condition near this equilibrium density (0.37) and at 2 lower densities (0.22 and 0.17). Annual population growth rates were evaluated at 4, 18, and 24% respectively. We predicted that moose in the high density area would exhibit growth retardation and poorer body condition, compared to moose in the lower density areas. Measurements of head length, cranial breadth, heart weight, and kidney weight were collected from 443 moose killed during the regular autumn harvesting seasons of 1981 and 1982. There was no indication that body condition was poorer at high moose density, and hence no evidence that foraging conditions were deteriorated. We concluded that food limitation was not sufficient to explain the differences in population growth rates. Predation by wolves and/or black bears is presented as an alternative and testable hypothesis.

Growth and development of the Murid Pseudomys novaehollandiae

Growth of the hind foot, head and weight were studied from birth to 150 days of age in a captive colony of P. novaaehollandiae, and development of external body features was recorded from birth to weaning. The altricial young were sparsely haired and blind at birth and a juvenile pelage was present by about 10 days. The eyes opened at 15 (13-19) days and the young were weaned during the fourth week. Instantaneous relative growth rates showed that growth (weight) during the first 40 days was multiphasic and that the growth rate changed considerably at both the opening of the eyes and weaning. The relationships of seven body measurements (head and body, head, ear, foreleg, hind leg, hind foot and tail) were compared to a linear equivalence of weight; all showed a sigmoidal relationship except that of head and body, which was a straight line. Hind foot and head length measurements of growing animals reached 90% of adult size at about 26 days, and weight at about 85 days. In Australian murids, one group grows relatively quickly and another grows slowly.

The Effect of Storage in Vitro on the Dna Content of Bull Spermatozoa

Bull spermatozoa were aged in vitro for periods of up to 9 days. Microspectro. photometric measurements were made of the nuclear DNA content of the sperm heads using ultraviolet absorption, acridine orange fluorescence, and Feulgen staining and of the nuclear histone content using fast green staining. The surface area of the sperm heads was calculated from linear measurements of head length and width.