Forward Stepwise Discriminant Function Analysis Research Articles

Revision of the <em>Calotheca nigrotessellata</em> species group from southern Africa, with description of two new species (Coleoptera: Chrysomelidae, Galerucinae, Alticini)

Calotheca Heyden is a mostly sub-Saharan flea beetle genus, comprising twenty-seven species previously included in Blepharida Chevrolat. The examination of new material is revealing a high species richness, as there is high intraspecific variability. Calotheca luteomaculata sp. nov. from Zimbabwe and the Republic of South Africa, and C. luteotessellata sp. nov. from the Republic of South Africa are here described and attributed to the C. nigrotessellata (Baly) species group, mainly based on genitalic characters. Photographs of the main diagnostic characters are supplied, including the median lobe of the aedeagus and spermatheca. A forward stepwise discriminant function analysis, using morphometric variables, has been performed. It supports the attribution of the examined specimens to the three species here considered, thus adding characters useful for their identification. Information on geographical distribution and host plants are also provided.

Individual Identification of Male Ural Owls Based on Territorial Calls

Effective individual identification is important in many aspects of animal studies. Leg bands and wing tags are commonly used to mark individual birds in the field; however, for nocturnal or cryptic birds it is difficult to directly observe individual tags due to darkness or dense vegetation. Alternatively, some studies suggest that many birds have individually distinctive vocalizations, and these differences could be used to identify individuals. Here we assessed the possibility of identifying individual Ural Owls (Strix uralensis) based on their defensive territorial hooting calls. During breeding season, we recorded hooting calls of 15 males in 2018 and of 16 males in 2019 respectively at the Dagangzi national forest in northeastern China. We measured 19 variables for each call. Using forward stepwise discriminant function analysis, we correctly classified 92.8% of the calls of individuals in 2018 and 93.9% in 2019, based on leave-one-out cross validation. The most important discriminating variables included duration of the interval between the first and second notes, duration of the interval between the second and third notes, the third note duration, and the number of “humps” (upward projections in a note in the sound spectrogram) in the first note. The calls of individuals remained stable both within a breeding season and between years. Our results suggest that territorial calls are effective for identifying male Ural Owl individuals, and this technique could contribute to population surveys and long-term monitoring.

The Roles of Growth, Maturation, Physical Fitness, and Technical Skills on Selection for a Portuguese Under-14 Years Basketball Team.

This study investigated the roles of growth, maturation, physical fitness, and technical skills on selection onto an under-14 years basketball team. The sample consisted of 150 male players, aged 13.3 ± 0.7 years, divided into selected (SE—top players chosen by coaching staff to form an elite regional team) and non-selected (NSE—remaining players) groups. Anthropometry, body composition, biological maturation, and training experience data were collected using standard procedures. Physical fitness was assessed using the Yo-Yo IE2, sit-ups, handgrip, squat jump, countermovement jump, 3 kg medicine ball throw, 20 m sprint, and T-Test. Technical skills were acquired using the American Alliance for Health, Physical Education, Recreation, and Dance (AAHPERD)’s basketball-specific test battery. Groups were compared using a Student’s t test and multivariate analysis of covariance (MANCOVA), with training experience and biological maturation as covariates. A forward stepwise discriminant function analysis was employed to identify variables that maximized the separation between groups. The results showed that SE players were taller, had greater fat-free mass, greater strength, power, and agility, and were technically more skillful compared with NSE players (p < 0.05) when controlling for training experience and maturation. It was also found that players were best discriminated by the 3 kg medicine ball throw and control dribble, revealing the importance of qualified training to achieve excellence in youth basketball. 92.7% of the basketballers were correctly classified into their original groups. It is therefore confirmed that the additional effects of training experience and biological maturation positively influenced the performance of young basketball players. We recommend that coaches focus not only on players’ body sizes, but also on their skill level, especially during adolescence, when selecting teams in order to promote sustainable long-term development.

Multivariate Profiles of Selected versus Non-Selected Elite Youth Brazilian Soccer Players.

This study determined whether a multivariate profile more effectively discriminated selected than non-selected elite youth Brazilian soccer players. This examination was carried out on 66 youth soccer players (selected, n = 28, mean age 16.3 ± 0.1; non-selected, n = 38, mean age 16.7 ± 0.4) using objective instruments. Multivariate profiles were assessed through anthropometric characteristics, biological maturation, tactical-technical skills, and motor performance. The Student’s t-test identified that selected players exhibited significantly higher values for height (t = 2.331, p = 0.02), lean body mass (t = 2.441, p = 0.01), and maturity offset (t = 4.559, p < 0.001), as well as performed better in declarative tactical knowledge (t = 10.484, p < 0.001), shooting (t = 2.188, p = 0.03), dribbling (t = 5.914, p < 0.001), speed – 30 m (t = 8.304, p < 0.001), countermovement jump (t = 2.718, p = 0.008), and peak power tests (t = 2.454, p = 0.01). Forward stepwise discriminant function analysis showed that declarative tactical knowledge, running speed –30 m, maturity offset, dribbling, height, and peak power correctly classified 97% of the selected players. These findings may have implications for a highly efficient selection process with objective measures of youth players in soccer clubs.

Distinctiveness in the Territorial Calls of Great Horned Owls within and among Years

Many animals have vocalizations that are individually distinguishable. Researchers can use these differences to facilitate monitoring of individuals. To be an effective monitoring tool, vocalizations must be recognizable throughout a season and preferably throughout an animal's lifetime. We assessed whether the territorial calls of Great Horned Owls (Bubo virginianus) are individually distinct, both within a season and over several years. Both males and females could be readily identified by their territorial calls. Based on a comparison of within- to between-individual coefficients of variation and a multivariate analysis of variance (MANOVA), nearly all vocal characteristics we measured carried individually distinct information. Using forward stepwise discriminant function analysis (DFA), we found that the internote interval between the last short and first long note of the call was the most useful for identifying both individual males and females. The duration and minimum and maximum frequency of long notes were important for discriminating among individual males whereas the number of notes and total call duration were important characteristics for identifying individual females. Using cross-validation DFA, both male and female Great Horned Owls were accurately assigned to location both throughout a season and among years. Correct assignment of males was reduced across recording sessions and among years compared to within a recording session, but was still greater than expected by chance. Together, our results suggest that individually distinct vocalizations could be an effective tool for identification of Great Horned Owls for long-term monitoring.Muchos animales tienen vocalizaciones que son distinguibles individualmente. Los investigadores pueden usar estas diferencias para facilitar el monitoreo de individuos. Para ser una herramienta de monitoreo efectiva, las vocalizaciones deben ser reconocibles a través de una estación y preferentemente a lo largo de la vida de un animal. Evaluamos si las llamadas territoriales de Bubo virginianus son distinguibles individualmente, en una estación y a lo largo de varios años. Tanto los machos como las hembras pudieron ser identificados por sus llamadas territoriales. Basados en una comparación de coeficientes de variación de un individuo y entre individuos y un análisis de la varianza multivariado (MANOVA), casi todas las características vocales que medimos tuvieron información distintiva individual. Usando análisis de función discriminante (AFD) por pasos hacia adelante, encontramos que el intervalo entre la última nota corta y la primera nota larga del llamado fue el más útil para identificar a los individuos machos y hembras. La duración y las frecuencias máximas y mínimas fueron importantes para la discriminación entre los individuos machos, mientras que el número de notas y la duración total del llamado fueron características importantes para la identificación de los individuos hembras. Usando el AFD de validación cruzada, tanto los machos como las hembras de B. virginianus fueron asignados con precisión a una ubicación a lo largo de una estación y entre años. La asignación correcta de machos fue más baja entre distintas sesiones de grabación y entre años comparada con una misma sesión de grabación, pero de todas maneras fue mayor que la esperada por azar. En conjunto, nuestros resultados sugieren que las vocalizaciones distinguibles individualmente pueden ser una herramienta efectiva para la identificación de individuos de B. virginianus en monitoreos a largo plazo.

Morphoscopic trait expressions used to identify Southwest Hispanics.

Hispanics represent the largest and fastest growing minority in the United States. It is increasingly important to understand the skeletal morphology and regional variation within this diverse group. This research focuses on the eight cranial morphoscopic traits of Southwest Hispanics from Birkby et al. (J Forensic Sci 2008;53(1):29-33) and 18 additional traits. Frequency distributions assessed the prevalence of trait expressions in Southwest Hispanic, African-American, and European-American samples. Forward stepwise discriminant function analysis indicated the best traits for differentiating these three groups. Six of the Birkby et al.'s traits are prevalent in the Southwest Hispanic sample and the best traits to distinguish the three groups are as follows: incisor shoveling, anterior malar projection, nasal sill, oval window visualization, enamel extensions, anterior nasal spine, nasal aperture width, and alveolar prognathism. This research demonstrates the efficacy of morphoscopic traits in ancestry determinations and the utility of the aforementioned traits in discriminating Southwest Hispanics, African Americans, and European Americans.

Predicting the sex of the Sedge Warbler (Acrocephalus schoenobaenus) by discriminant analysis

Sexual size dimorphism was examined in 273 immature Sedge Warblers (Acrocephalus schoenobaenus) caught in northern Poland during autumn migration in 2008 and 2009. Each individual was measured (wing, tail, head to bill, bill length, bill width, bill height, two measurements of tarsus width and hind claw length) and a blood sample was taken for molecular sexing. A forward stepwise discriminant function analysis was used and three discriminant functions were proposed for sexing Sedge Warblers. The first function, ap-plied to the nine measurements, identified wing and bill length as the best measurements for sexing and correctly classified 82% of individuals. The second and third functions, ap-plied to only wing length and tail length, identified the former as the best single measure-ment, and these two correctly classified 83% and 82% individuals, respectively. These functions may be used as a tool for sexing Sedge Warblers when blood sampling is impos-sible, such as in historical ringing records. However, the functions may be valid only for young birds in north and central Europe measured by experienced ringers.

Use of parasites as tags in delineating stocks of Atlantic cod ( Gadus morhua) from the southern Gulf of St. Lawrence and the Cape Breton Shelf

Parasites were inventoried on and in 470 Atlantic cod ( Gadus morhua) collected from the southern Gulf of St. Lawrence, NAFO (North Atlantic Fisheries Organization) division 4T, and Cape Breton Shelf (NAFO subdivision 4Vn) in September of 2004 and 2005, and August 2006, respectively. Forward stepwise discriminant function analysis (DFA) of the 4T samples indicated that the nematodes, Hysterothylacium aduncum, and Pseudoterranova decipiens and the acanthocephalans Echinorhynchus gadi and Corynosoma strumosum were significant in the classification of cod to eastern or western 4T. Cross-validation yielded a classification efficiency of 74% overall, thereby supporting the findings of earlier mark-recapture studies which have indicated that 4T cod are comprised of discrete eastern and western spawning groups. Further analyses indicated that western 4T cod was distinct not only from eastern 4T cod, but also differed from cod from the Smokey Channel and Cape Breton Shelf slopewaters (4Vn), with rates of misclassification ranging from 6% to 9%. Hence, “parasite tags” may prove useful for monitoring the exploitation of cod from western 4T during their annual migration through the Cabot Strait and while over-wintering along the edge of the Cape Breton Shelf where mixing with eastern 4T and 4Vn cod may occur. Similar results could be achieved with migrant cod from eastern 4T through analyses of parasite markers together with host meristic or morphometric parameters.

Variation in Eastern Cottonwood (&lt;I&gt;Populus deltoides&lt;/I&gt; Bartr.) Phloem Sap Content Caused by Leaf Development May Affect Feeding Site Selection Behavior of the Aphid, &lt;I&gt;Chaitophorous populicola&lt;/I&gt; Thomas (Homoptera: Aphididae)

Apterous populations of Chaitophorous populicola Thomas (Homoptera: Aphididae) appear to track Eastern cottonwood (Populus deltoides Bartr.) leaf development. Few aphids occur on mature leaves. Marked individual aphids on leaves of different developmental stages were observed through a period of new leaf initiation. Nymph and adult C. populicola frequently track leaf development by moving up to younger leaves. A comparison of phloem sap constituents and leaf toughness among leaf developmental stages revealed some differences that could be used by C. populicola to determine leaf age. Phloem sap exudates, collected from P. deltoides leaves of different developmental stages, were analyzed by high-performance liquid chromatography for free amino acids and the phenolic glycoside salicin. Sucrose concentration in exudates, indicative of phloem sap exudation rate, was uniform among leaf stages. Of 20 amino acids examined, only aspartic acid and gamma-amino-n-butyric acid (GABA) concentrations differed significantly between leaf stages. Forward stepwise discriminant function analysis showed that seven of the amino acids analyzed are useful for classifying leaf maturity groupings. Aphid-infested cottonwoods had lower cystine concentrations in phloem sap than aphid-free plants. Salicin concentration was significantly higher in new leaves. Leaf toughness was assessed by lignin density and distance measurements in petiole cross-sections. Rapidly expanding leaves had significantly less lignification and new leaves had shorter distances to the vascular bundles than senescent leaves. These physiological and phytochemical differences among P. deltoides leaf developmental stages may contribute to the leaf stage selection patterns exhibited by the aphid, C. populicola.

Predicting the Sex of Dovekies by Discriminant Analysis

We examined sexual dimorphism of Dovekie (Alle alle) from the breeding colony in Hornsund (south Spitsbergen). Each bird was sexed using DNA extracted from blood. Body morphometrics including flattened wing, head-bill, tarsus length, bill width and body mass were recorded in 331 birds caught during the breeding season in 2003-2006. Analysis of measurements of mated pairs showed that males are usually bigger than females in case of head-bill length, bill width and body mass. Only head-bill length was significantly correlated within a pair (r69 = 0.354, P < 0.005). A forward stepwise discriminant function analysis (DFA) was used to evaluate sexual size dimorphism in Dovekie. The first function, applied to 4 measurements, identified head-bill length and bill width as the best measurements for sexing and correctly classified 70% of our sample (but only 38% better than chance). The second function, which was applied to only 3 parameters (excluding bill width), identified head-bill length as the best measurement for sexing and correctly classified 65% of our sample (30% better than chance). In Dovekie, a species having a high degree of overlap between the sexes, discriminant function should be used with caution. It is recommended that a combination of morphometrics, behavior observation and genetic analysis be used to obtain the highest accuracy in sexing individuals correctly.

Nontraditional atherosclerotic risk factors and extent of coronary atherosclerosis in patients with combined impaired fasting glucose and impaired glucose tolerance

Partially inconsistent data exist on mutual relations between nontraditional atherosclerotic risk factors, including the magnitude of insulin resistance (IR), as well as on their relevance for atherogenesis in the metabolic syndrome. Subjects exhibiting combined impaired fasting glucose and impaired glucose tolerance (IFG/IGT) are exposed to an exceptionally high risk for atherogenesis and development of type 2 diabetes mellitus. Because of islet Β-cell dysfunction, the usefulness of commonly used indices of IR is limited in IFG/IGT. Our aim was to assess the relationship between extent of angiographic coronary artery disease (CAD) and nontraditional atherosclerotic risk factors (including IR by a clamp-based golden standard method) in IFG/IGT. Fifty-three subjects (32 men, 21 women; mean age, 55 ± 11 years) with stable angina, preserved left ventricular systolic function, and IFG/IGT were divided into 3 groups: group A (no coronary stenoses >50%, n = 22), group B (1-vessel CAD, n = 15), and group C (2/3-vessel CAD, n = 16). Insulin sensitivity was quantified by a hyperinsulinemic euglycemic clamp technique and expressed as M. M value, plasma homocysteine (Hcy) level, and asymmetric dimethyl- l-arginine (ADMA)/ l-arginine ratio were independent determinants of CAD extent as shown by forward stepwise discriminant function analysis. Compared with group A ( M = 32.7 ± 9.3 μmol/kg fat-free mass [FFM] per minute; Hcy, 8.1 ± 1.4 μmol/L), lower M and higher Hcy levels were found in group B ( M = 16.9 ± 8.2 μmol/kg FFM per minute, P < .001; Hcy, 11.2 ± 2.9 μmol/L, P = .003) and C ( M = 16.4 ± 7.8 μmol/kg FFM per minute, P < .001; Hcy, 12.8 ± 3.9 μmol/L, P < .001). The ADMA/ l-arginine ratio was increased in group C (0.0078 ± 0.0011) compared with group A (0.0063 ± 0.0013, P = .03) and B (0.0058 ± 0.0012, P = .01). Multivariate correlates ( P < .05) of plasma Hcy concentrations were M ( β = −.34 ± .12, P = .008), creatinine clearance ( β = −.23 ± .10, P = .03) and fasting insulin ( β = .25 ± .12, P = .04). This indicates an additive contribution of IR, plasma Hcy, and elevated ADMA/ l-arginine ratio to the extent of angiographic CAD in combined IFG/IGT.

Geochemical Signatures in Scales Record Stream of Origin in Westslope Cutthroat Trout

AbstractWe used laser ablation inductively coupled plasma mass spectrometry (ICP‐MS) to quantify the elemental composition of Mg: Ca, Mn: Ca, Sr: Ca, Ba: Ca, and Pb: Ca ratios in scales from juvenile westslope cutthroat trout Oncorhynchus clarkii lewisi collected from 13 streams in three major drainages (North Fork, South Fork, and Middle Fork) of the upper Flathead River system in Montana during summer 2001 and 2002. We also determined element: Ca levels within natal streams in summer 2001 and 2002. The concentrations of Sr: Ca and Ba: Ca in westslope cutthroat trout scales were highly correlated with those in the water. The multivariate elemental signatures of the scales differed significantly among streams. A forward stepwise discriminant function analysis was used to classify individual fish, first to the drainage of origin and then to the natal stream while considering all 13 streams simultaneously. At the drainage level, cross‐validated classification accuracy was 91% in the Middle Fork, 81% in the North Fork, and 78% in the South Fork; overall accuracy was 82%. Of the fish that were correctly classified at the drainage level, 88% were correctly classified to their natal stream at accuracy levels of 100% in the Middle Fork, 88% in the North Fork, and 80% in the South Fork. Finally, the Mn: Ca, Sr: Ca, and Ba: Ca ratios in westslope cutthroat trout scales were significantly correlated with values in the otoliths of individual fish, suggesting that scales may provide a nonlethal alternative to otoliths as natural markers. Our data indicate that elemental signatures in scales may be used as natural tags to identify the natal stream origin of westslope cutthroat trout in the upper Flathead River system and in other similar freshwater environments. However, future work needs to determine whether elemental signatures are sufficiently stable over time to allow for accurate classification of adult fish after emigration from natal streams.

Vocal identification of individual African Wood Owls Strix woodfordii: a technique to monitor long‐term adult turnover and residency

The hoot‐calls of Wood Owls Strix woodfordii, recorded in the Kruger National Park, South Africa, from 1986 to 1998, are sufficiently different to distinguish individuals. Thirteen hoot‐call variables, measured from recordings over this period, show that male and female Wood Owls have such temporal stability that these calls can be used reliably as a long‐term census technique. manova, based on ordinations from principal component analysis, was used to identify individuals statistically between sampling periods. A forward stepwise discriminant function analysis achieved 100% classification success of individual male (n = 3) and female (n = 4) owls from a single sampling period. For all the individuals recorded over the whole study period we achieved a classification success of 80.9% (n = 9) for male hoot calls and of 96.3% (n = 13) for female calls. We found mean occupation periods of 82.25 and 65 months and annual turnover rates of 19.3% and 13.65% for males and females, respectively. Our survey, using vocalizations, is unique since we use data collected over a 12‐year period to derive estimates of population turnover in Wood Owls, and consider what questions can be addressed in similar studies.

Difference in symptom profile between generalized anxiety disorder and anxiety secondary to hyperthyroidism.

The differential diagnosis between subclinical hyperthyroidism and Generalized Anxiety Disorder (GAD) is often a difficult problem to solve without laboratory examination. The aim of this pilot study was to assess whether there are differences in the symptom profile between these two disorders. Fifty patients took part in the study: Twenty-five were hyperthyroid patients, and twenty-five were GAD patients. The diagnosis was based on the TSH values and the DSM-IV criteria, respectively. The Hamilton Anxiety Scale (HAS) and the list of fifty-one symptoms produced by the detailed expansion of HAS items were used to quantify the anxiety symptomatology. The differences in the frequencies between the two diagnostic groups were calculated at each categorical response for every item of both scales. Forward Stepwise Discriminant Function Analysis was performed twice using HAS items and the fifty-one-list items. The symptoms of anxiety in subclinical hyperthyroidism were not identical to those of GAD. Four Hyperthyroid/Anxiety Indices (HAI I-IV) were developed. These indices reach optimum classification of patients (3 of them reach 100% sensitivity and specificity). The results of the current study suggest that it is possible to differentiate between GAD and subclinical cases of hyperthyroidism by the careful study of clinical symptomatology. This may be of particular help in isolated areas without laboratory support, but replication of the indices in other samples is indicated.