Assessing complexity in hominid dental evolution: Fractal analysis of great ape and human molars

OBJECTIVES: Molar crenulation is defined as the accessory pattern of grooves that appears on the occlusal surface of many mammalian molars. Although frequently used in the characterization of species, this trait is often assessed qualitatively, which poses unavoidable subjective biases. The objective of this study is to quantitatively test the variability in the expression of molar crenulation in primates and its association with molar size and diet. METHODS: The variability in the expression of molar crenulation in hominids (human, chimpanzee, gorilla, and orangutan) was assessed with fractal analysis using photographs of first, second and third upper and lower molars. After this, representative values for 29 primate species were used to evaluate the correlation between molar complexity, molar size, and diet using a phylogenetic generalized least squares regression. RESULTS: Results show that there are statistically significant differences in fractal dimensions across hominid species in all molars, with orangutan molars presenting higher values of occlusal complexity. Our results indicate that there is no significant association between molar complexity and molar size or diet. DISCUSSION: Our results show higher levels of occlusal complexity in orangutans, thus supporting previously published observations. Our analyses, however, do not indicate a clear association between molar complexity and molar size or diet, pointing to other factors as the major drivers of complexity. To our knowledge, our study is the first one to use fractal analysis to measure occlusal complexity in primates. Our results show that this approach is a rapid and cost-effective way to measure molar complexity

Dental evolutionary rates and its implications for the Neanderthal–modern human divergence

The origin of Neanderthal and modern human lineages is a matter of intense debate. DNA analyses have generally indicated that both lineages diverged during the middle period of the Middle Pleistocene, an inferred time that has strongly influenced interpretations of the hominin fossil record. This divergence time, however, is not compatible with the anatomical and genetic Neanderthal affinities observed in Middle Pleistocene hominins from Sima de los Huesos (Spain), which are dated to 430 thousand years (ka) ago. Drawing on quantitative analyses of dental evolutionary rates and Bayesian analyses of hominin phylogenetic relationships, I show that any divergence time between Neanderthals and modern humans younger than 800 ka ago would have entailed unexpectedly rapid dental evolution in early Neanderthals from Sima de los Huesos. These results support a pre–800 ka last common ancestor for Neanderthals and modern humans unless hitherto unexplained mechanisms sped up dental evolution in early Neanderthals

Morphological integration in the gorilla, chimpanzee, and human neck.

OBJECTIVES: Although integration studies are important to understand the evolution of organisms' traits across phylogenies, vertebral integration in primates is still largely unexplored. Here we describe and quantify patterns of morphological integration and modularity in the subaxial cervical vertebrae (C3-C7) in extant hominines incorporating the potential influence of size. MATERIALS AND METHODS: Three-dimensional landmarks were digitized on 546 subaxial cervical vertebrae from 141 adult individuals of Gorilla gorilla, Pan troglodytes, and Homo sapiens. Integration and modularity, and the influence of size effects, were quantified using geometric morphometric approaches. RESULTS: All subaxial cervical vertebrae from the three species show a strong degree of integration. Gorillas show the highest degree of integration; conversely, humans have the lowest degree of integration. Analyses of allometric regression residuals show that size is an important factor promoting integration in gorillas, with lesser influence in chimpanzees and almost no effect in humans. DISCUSSION: Results point to a likely ancestral pattern of integration in non-human hominines, whereby the degree of integration decreases from cranial to caudal positions. Humans deviate from this pattern in the cranialmost (C3) and, to a lesser extent, in the caudalmost (C7) vertebrae, which are less integrated. These differences can be tentatively related to the emergence of bipedalism due to the presence of modern human-like C3 in australopiths, which still preserve a more chimpanzee-like C7

Neanderthal teeth from Lezetxiki (Arrasate, Iberian Peninsula): New insights and reassessment

Objectives: We reassess the taxonomic assignment and stratigraphic context of a permanent upper first molar and a permanent lower third premolar recovered from the archeological site of Lezetxiki in the North of the Iberian Peninsula. Materials and Methods: We assessed the external and internal morphology of the teeth using qualitative descriptions, crown diameters, dental tissue proportions, and geometric morphometrics. The teeth from Lezetxiki were compared with Middle Pleistocene specimens, Neanderthals, Upper Paleolithic modern humans, and recent modern humans. Results: Both teeth were consistent with a Neanderthal classification. The upper first molar shows taurodontism, and its cusp proportions and overall morphology match those of Neanderthals. Geometric morphometric analyses of occlusal anatomy classify this molar as a Neanderthal with a posterior probability of 76%. The lower third premolar, which was originally classified as a lower fourth premolar, also shows a Neanderthal morphology. This premolar is classified as a Neanderthal with a posterior probability of 60%. Discussion: These teeth represent the only adult Neanderthal teeth from the Western Pyrenees region found to date. The teeth were found at a stratigraphic level (designated Level III) that marks the transition level from Mousterian to Aurignacian, and are among the most recent Neanderthal remains from the north of the Iberian Peninsula

Niveles de infección de helmintos de Rattus rattus (Rodentia: Muridae) en la ciudad de Corrientes, Argentina

The aim of this study was to describe the infection levels of helminths of Rattus rattus in Corrientes city, Corrientes Province, Argentina. In order to determine the role of rodents as potential reservoirs for zoonotic parasites, different indices of helminth infection were assessed with respect to sex, age, season and urban landscapes. A total of 107 individuals of R. rattus were examined. Seven species of helminths were found. The values of total prevalence, mean intensity and mean abundance were 68%, 20 and 13, respectively. Nippostrongylus brasiliensis was the species more prevalent and abundant. The results showed that the age of the rodents and the season of capture had effects on the helminth infection.El objetivo del trabajo fue describir los niveles de infección de Rattus rattus en la ciudad de Corrientes, provincia de Corrientes, Argentina. Con el objetivo de determinar el rol de los roedores como reservorios potenciales de parásitos zoonóticos, se analizó la distribución de helmintos respecto al sexo, edad, estación del año y ambientes urbanos. Un total de 107 individuos de R. rattus fueron examinados. Se identificaron siete especies de helmintos. Los valores de prevalencia total, intensidad media y abundancia media fueron 68%, 20 y 13, respectivamente. Nippostrongylus brasiliensis fue la especie más prevalente y abundante. Los resultados demostraron que la edad de los roedores y la estación del año tuvieron efectos en la infección con helmintos.Facultad de Ciencias Naturales y Muse

Niveles de infección de helmintos de Rattus rattus (Rodentia: Muridae) en la ciudad de Corrientes, Argentina

The aim of this study was to describe the infection levels of helminths of Rattus rattus in Corrientes city, Corrientes Province, Argentina. In order to determine the role of rodents as potential reservoirs for zoonotic parasites, different indices of helminth infection were assessed with respect to sex, age, season and urban landscapes. A total of 107 individuals of R. rattus were examined. Seven species of helminths were found. The values of total prevalence, mean intensity and mean abundance were 68%, 20 and 13, respectively. Nippostrongylus brasiliensis was the species more prevalent and abundant. The results showed that the age of the rodents and the season of capture had effects on the helminth infection.El objetivo del trabajo fue describir los niveles de infección de Rattus rattus en la ciudad de Corrientes, provincia de Corrientes, Argentina. Con el objetivo de determinar el rol de los roedores como reservorios potenciales de parásitos zoonóticos, se analizó la distribución de helmintos respecto al sexo, edad, estación del año y ambientes urbanos. Un total de 107 individuos de R. rattus fueron examinados. Se identificaron siete especies de helmintos. Los valores de prevalencia total, intensidad media y abundancia media fueron 68%, 20 y 13, respectivamente. Nippostrongylus brasiliensis fue la especie más prevalente y abundante. Los resultados demostraron que la edad de los roedores y la estación del año tuvieron efectos en la infección con helmintos.Facultad de Ciencias Naturales y Muse

goseigo ni mirareru onsokotai

The spatial distribution and competition for the use of resources between sheep —transhumant merino— and chamois Rupicapra pyrenaica parva. Cabrera, 1910) has been analyzed during the summer grazing period in the Cantabrian range. The studied area, —a 750 ha. wide high pass— was divided into sectors depending on geophysical variables (substratum, aspect and elevation) and vegetation types. Sheep land use was analyzed by direct observation of the flock and by means of enquiries to the shepherd. Chamois were studied before and during the time sheep were present in the pastureland, with the help of fixed itineraries that enabled us to visually cover the whole area. The assessment of land use was carried out by corrected frequency and preference index for each of the studied environmental variables. Sheep grazed in the whole area excepting for beech woods (Fagus sylvatica), rocky and steep zones and dense scrub patches.The location of the sheepfolds —shelters, enclosures and associated pastures— is a key factor in the management of the pastoral system. They are usually placed in a central position from where the flock make their every day course, normally directed to higher zones, in the studied area, chamois distribution is limited by the scarcity of zones over 1.800 m., and by the strong sheep grazing pressure at all elevations. Chamois leave the areas grazed by the sheep flock, creating an almost total segregation. They occupy steep rocky slopes and the beech woods edges close to them, both situated furthest away from the sheepfolds.[es] Durante el periodo estival de utilización de los pastos de puerto en la Cordillera Cantábrica, se analiza la distribución espacial de las ovejas —merinas trashumantes— y rebecos —Rupicapra pyrenaica parva. Cabrera 1910— y su posible competencia en el uso de los recursos. Como referencia se llevó a cabo una sectorización del territorio —750 ha.— según variables geofísicas (sustrato geológico, orientación y altitud) y tipos de vegetación. La utilización de los pastos por las ovejas fue analizada por seguimiento directo del rebaño y mediante encuestas al pastor. Los rebecos se estudiaron antes y durante la estancia de las ovejas, con itinerarios fijos que permitían cubrir visualmente toda el área de estudio. El uso del territorio se analiza mediante frecuencias corregidas e índices de preferencia para cada uno de los sectores temáticos considerados. Las ovejas pastaron toda el área rechazando tan solo los hayedos, las zonas rocosas de mayor pendiente y las manchas cerradas de matorral. La ubicación de las majadas (refugio nocturno y pastos asociados) es un aspecto clave en el aprovechamiento del puerto.Se sitúan en posición central, desde la que se realizan recorridos —careos— hacia pastos situados normalmente en zonas más altas. La distribución de rebecos se ve limitada por la escasa representación de cotas superiores a 1.800 m. de altitud, así como por la fuerte presión que ejercen las ovejas al pastorear en todos los niveles altitudinales. Durante la estancia estival de las ovejas, los rebecos abandonan las áreas utilizadas por el rebaño, realizándose una segregación espacial casi completa. Se instalan en lugares rocosos con fuerte pendiente y en los bordes de hayedo próximos, localizados en las zonas más alejadas de las majadas. [fr] La distribution spatiale des ovins —merinos transhumants— et des chamois —Rupicapra pyrenaica parva (Cabrera, 1910)— et leur concurrence éventuelle pour l'utilisation des ressources, est analysée pendant la période estivale en alpages dans la Chaîne Cantabrique. Comme référence, une sectorisation du territoire —750 ha.— a été réalisée, d'après des variables géophysiques (substrat, exposition et altitude) et les types de végétation.L'utilisation des pâturages par les ovins a été analysée par suivi direct du troupeau et au moyen d'enquêtes auprès du berger. Les chamois ont été étudiés avant et pendant le séjour des moutons en alpage, en réalisant des itinéraires fixés, qui permettaient de couvrir visuellement la totalité de la zone d'étude. L'usage du territoire est analysé á l'aide de fréquences corrigées et d'indices de préférence pour chacun des secteurs thématiques considérés.Les moutons ont pâturé sur toute la zone, en refusant uniquement les hêtraies, les zones rocheuses avec une plus forte pente et les taches de buisson plus dense. La localisation des bergeries (refuge nocturne et pâturages associés) est un point clé dans l'utilisation de l'alpage. Ils se situent dans une position centrale, depuis laquelle sont effectués les parcours vers des pâturages qui se trouvent normalement sur les zones les plus hautes. La distribution des chamois est limitée par la réduite représentation de niveaux d'altitude supérieurs à 1.800 mètres, de même que par la forte pression exercée par les moutons qui pâturent sur tous les niveaux d'altitude. Pendant le séjour estival des moutons, les chamois abandonnent les zones utilisées par le troupeau, d'où une ségrégation spatiale presque complète. Ils s'installent dans les endroits rocheux ayant une plus forte pente, qui se trouvent dans les zones les plus éloignées des bergeries

The origin of the protostellar jet GGD 34

GGD 34 is a protostellar jet with wiggles which are accompanied by "sine-like" variations in the radial velocity of the emitting material by as much as 60 km s(-1). Thus GGD 34 is an interesting object to understand the physical mechanisms involved in the generation of wiggles in protostellar jets. In this work we present high resolution images obtained with the Canada-France-Hawaii Telescope (CFHT) which shows that GCD 34 consists of a narrow (unresolved) jet roughly bisecting an extended faint envelope. The [S II] emission from the working surface has an arrow shaped morphology; the body of the jet is clearly distinguished as well as two backtails disposed in an approximately symmetric manner with respect to the jet axis. The H alpha emission is concentrated at the head of the jet indicating that the gas is significantly more excited at this location tin particular at the so-called Knot 5); we suggest that Knot 5 traces the location of the Mach disk since spectra of GGD 34 indicate that it is a light beam of gas. The high resolution images also show that the envelope around GGD 34 connects smoothly with the back tails at the head of the jet. We speculate whether it traces the backflow; the expected backflow velocity is shown to be similar to 32 km s(-1) which is consistent with the degree of excitation of the envelope. However, an accurate determination of the proper motion of the head is necessary to check whether this interpretation is correct. We also present radiocontinuum (3.6 and 6 cm) VLA observations and report the detection of a radio source close to the apex of the cavity from which the jet emerges. This radio source has a spectral index of 0.7+/-0.5, consistent within error with the value of 0.6 expected for a thermal jet. We suggest that this radio object is associated with the source of the outflow. Additional (12)CO(3-2) observations obtained with the JCMT show molecular gas redshifted by similar to 2.5 km s(-1) with respect to the cloud at this location

Insulation Design of Low Voltage Electrical Motors Fed by PWM Inverters

This paper proposes a model to determine the partial discharge inception voltage of magnet wires, including the effect of elevated temperatures, and shows its applicability to the complete range of wire geometries considered in IEC Standard 60317-13