bluuebunny/crossref_metadata_2025_split huggingface dataset:
Herbivore metabolism and stoichiometry each constrain herbivory at different organizational scales across ecosystems
Authors: Hillebrand Helmut , Borer Elizabeth T. , Bracken Matthew E. S. , Cardinale Bradley J. , Cebrian Just , Cleland Elsa E. , Elser James J. , Gruner Daniel S. , Stanley Harpole W. , Ngai Jacqueline T. , Sandin Stuart , Seabloom Eric W. , Shurin Jonathan B. , Smith Jennifer E. , Smith Melinda D. 
Published: April 2009

AbstractPlant‐herbivore interactions mediate the trophic structure of ecosystems. We use a comprehensive data set extracted from the literature to test the relative explanatory power of two contrasting bodies of ecological theory, the metabolic theory of ecology (MTE) and ecological stoichiometry (ES), for per‐capita and population‐level rates of herbivory across ecosystems. We found that ambient temperature and herbivore body size (MTE) as well as stoichiometric mismatch (ES) both constrained herbivory, but at different scales of biological organization. Herbivore body size, which varied over 11 orders of magnitude, was the primary factor explaining variation in per‐capita rates of herbivory. Stoichiometric mismatch explained more variation in population‐level herbivory rates and also in per‐capita rates when we examined data from within functionally similar trophic groups (e.g. zooplankton). Thus, predictions from metabolic and stoichiometric theories offer complementary explanations for patterns of herbivory that operate at different scales of biological organization.
Self‐recognition affects plant communication and defense
Authors: Karban Richard , Shiojiri Kaori 
Published: April 2009

AbstractAnimals have the ability to distinguish self from non‐self, which has allowed them to evolve immune systems and, in some instances, to act preferentially towards individuals that are genetically identical or related. Self‐recognition is less well known for plants, although recent work indicates that physically connected roots recognize self and reduce competitive interactions. Sagebrush uses volatile cues emitted by clipped branches of self or different neighbours to increase resistance to herbivory. Here, we show that plants that received volatile cues from genetically identical cuttings accumulated less natural damage than plants that received cues from non‐self cuttings. Volatile communication is required to coordinate systemic processes such as induced resistance and plants respond more effectively to self than non‐self cues. This self/non‐self discrimination did not require physical contact and is a necessary first step towards possible kin recognition and kin selection.
Efficacy Beliefs in Coach–Athlete Dyads: Prospective Relationships Using Actor–Partner Interdependence Models
Authors: Jackson Ben , Beauchamp Mark R. 
Published: April 2009

The overall purpose of the study was to investigate prospective actor and partner effects (cf. Kenny, Kashy, & Cook, 2006) of interpersonal efficacy beliefs in relation to relationship commitment, satisfaction, and effort within coach–athlete dyads. Fifty youth tennis players (mean age = 15.52 years, SD = 1.45) and their coaches (mean age = 40.17 years, SD = 13.71) provided data related to their self‐efficacy, other‐efficacy, and relation‐inferred self‐efficacy (RISE) beliefs mid‐way through the competitive season. Three months later, participants provided data regarding personal effort, as well as relationship commitment and satisfaction. Actor–partner interdependence model analyses revealed positive actor effects for self‐efficacy in relation to effort, and for other‐efficacy in relation to commitment, effort, and satisfaction. Partner effects for other‐efficacy were found in relation to relationship commitment and effort. Finally, actor and partner effects were also evident for RISE beliefs; however, these relationships were moderated by the individual's role (i.e. athlete or coach), such that the direction of actor and partner effects differed for athletes and coaches. Implications for fostering effective coach–athlete relationships are discussed.Cette recherche avait pour objectif général l’étude des retombées éventuelles sur l’acteur et son partenaire (Cf.: Kenny, Kashy & Cook, 2006) des croyances en l’efficience interpersonnelle en relation avec l’implication, la satisfaction et l’effort au sein de la dyade entraîneur‐athlète. Cinquante jeunes joueurs de tennis (âge moyen = 15,52; σ= 1,45) et leurs entraîneurs (âge moyen = 40,17; σ= 13,71) ont fourni des données relatives à leurs représentations concernant l’auto‐efficience, l’efficience d’autrui et l’auto‐efficience émanant de la relation (RISE), cela au milieu de la période des compétitions. Trois mois plus tard, les sujets ont donné des informations se rapportant à leur effort personnel, leur implication relationnelle et leur satisfaction. Les analyses relevant du modèle de l’interdépendance acteur‐partenaire ont révélé des conséquences positives pour l’acteur en ce qui concerne l’auto‐efficience en relation avec l’effort et l’efficience d’autrui en relation avec l’implication, l’effort et la satisfaction. Les effets du partenaire pour l’efficacité d’autrui étaient en relation avec l’effort et l’implication relationnelle. Finalement, les effets du partenaire et de l’acteur apparaissaient également pour les croyances RISE; ces relations étaient toutefois modulées par les rôles individuels (athlète ou entraîneur), de telle sorte que le sens des effets acteur‐partenaire différait pour les athlètes et les entraîneurs. On réfléchit aux applications permettant d’améliorer l’efficacité des relations athlète‐entraîneur.
Entry, Exit and Productivity: Empirical Results for German Manufacturing Industries
Authors: Wagner Joachim 
Published: April 2009

Abstract
From a model by Hopenhayn, three hypotheses can be derived: (H1) Firms that exit in year t were less productive in t -1 than firms that continue to produce in t. (H2) Firms that enter in year t are less productive than incumbent firms in year t. (H3) Surviving firms from an entry cohort were more productive than nonsurviving firms from this cohort in the start year. This paper uses unique newly available panel datasets for all manufacturing plants from Germany (1995-2002) to test these hypotheses. All three hypotheses are supported empirically for West and East Germany.
Life‐history traits associated with fragmentation vulnerability of lizards in the Thousand Island Lake, China
Authors: Wang Y. , Zhang J. , Feeley K. J. , Jiang P. , Ding P. 
Published: April 2009

AbstractFollowing habitat fragmentation, the remnant faunal community will undergo a period of species loss or ‘relaxation.’ Theory predicts that species with particular life‐history traits, such as a small population size, small geographical range, low fecundity and large body size, should be more vulnerable to fragmentation. In this study, we investigated the relationships between the above life‐history traits and the fragmentation vulnerability index (the number of islands occupied) of five lizard species inhabiting recently isolated land‐bridge islands in the Thousand Island Lake, China. Data on life‐history traits were collected from field surveys (population density) and from the literature (body size, clutch size and geographical range size). The species–area relationships for lizards sampled from the mainland versus on the islands differed significantly (i.e. the number of species inhabiting islands was decreased relative to similar‐sized areas on the mainland), indicating that species extinction has occurred on all of the study islands following isolation. For the fragmentation vulnerability index, model selection based on Akaike's information criterion identified natural density at mainland sites as the best correlate of vulnerability to fragmentation, supporting the hypothesis that rare species are most vulnerable to local extinction and will be lost first from fragmented landscapes. In contrast, there was little evidence for an effect of lizards' snout–vent length, clutch size or geographical range size on fragmentation vulnerability. Identification of species traits that render some species more vulnerable to fragmentation than others has important implications for conservation and can be used to aid direct management efforts.
Functional morphology and biomechanics of the tongue‐bite apparatus in salmonid and osteoglossomorph fishes
Authors: Camp Ariel L. , Konow Nicolai , Sanford Christopher P. J. 
Published: April 2009

AbstractThe tongue‐bite apparatus and its associated musculoskeletal elements of the pectoral girdle and neurocranium form the structural basis of raking, a unique prey‐processing behaviour in salmonid and osteoglossomorph fishes. Using a quantitative approach, the functional osteology and myology of this system were compared between representatives of each lineage, i.e. the salmonid Salvelinus fontinalis (N = 10) and the osteoglossomorph Chitala ornata (N = 8). Divergence was found in the morphology of the novel cleithrobranchial ligament, which potentially relates to kinematic differences between the raking lineage representatives. Salvelinus had greater anatomical cross‐sectional areas of the epaxial, hypaxial and protractor hyoideus muscles, whereas Chitala had greater sternohyoideus and adductor mandibulae mass. Two osteology‐based biomechanical models (a third‐order lever for neurocranial elevation and a modified four‐bar linkage for hyoid retraction) showed divergent force/velocity priorities in the study taxa. Salvelinus maximizes both force (via powerful cranial muscles) and velocity (through mechanical amplification) during raking. In contrast, Chitala has relatively low muscle force but more efficient force transmission through both mechanisms compared with Salvelinus. It remains unclear if and how behavioural modulation and specializations in the post‐cranial anatomy may affect the force/velocity trade‐offs in Chitala. Further studies of tongue‐bite apparatus morphology and biomechanics in a broader species range may help to clarify the role that osteology and myology play in the evolution of behavioural diversity.
The role of angiotensin‐(1–7) receptor Mas in spermatogenesis in mice and rats
Authors: Leal Marcelo C. , Pinheiro Sérgio V. B. , Ferreira Anderson J. , Santos Robson A. S. , Bordoni Leonardo S. , Alenina Natalia , Bader Michael , França Luiz R. 
Published: April 2009

AbstractEvidence regarding the components of the renin–angiotensin (Ang) system suggests that this system plays an important role in male reproduction. However, there are few data available in the literature on the effects of Ang‐(1–7) on the male reproductive system. The present study investigated the effects of the genetic deletion and chronic blockage of Ang‐(1–7) receptor Mas on spermatogenesis and male fertility. The localization of Mas in mouse and rat testes was determined by binding assays and immunofluorescence, whereas the testis structure and spermatogenic process were morphologically and stereologically analysed by light microscopy. Ang‐(1–7) binding and immunofluorescence revealed the presence of Mas in the testes of mice and rats. Although the total numbers of Sertoli and Leydig cells per testis and Leydig cell size were similar in both wild‐type and Mas‐deficient mice, Mas−/– animals exhibited a significant reduction in testis weight and a greater volume of apoptotic cells, giant cells and vacuoles in the seminiferous epithelium. In both mice and rats, an increased number of apoptotic cells were found during meiosis. Due to disturbed spermatogenesis, daily sperm production was markedly reduced in Mas−/– mice. Moreover, chronic infusion of A‐779 [an Ang‐(1–7) antagonist] in rats significantly increased the total number of apoptotic cells and primary spermatocytes in particular stages of spermatogenesis. Taken together, these findings strongly suggest that Ang‐(1–7) receptor Mas plays an important role in the regulation of spermatogenesis.
Petrosal anatomy and inner ear structures of the Late Jurassic Henkelotherium (Mammalia, Cladotheria, Dryolestoidea): insight into the early evolution of the ear region in cladotherian mammals
Authors: Ruf Irina , Luo Zhe‐Xi , Wible John R. , Martin Thomas 
Published: April 2009

AbstractThe petrosal anatomy and inner ear structure of Jurassic cladotherian mammals represent the ancestral morphological conditions (groundplan) from which modern therian mammals (marsupials and placentals) have evolved. We present the reconstruction of the petrosal and inner ear features of the Late Jurassic dryolestoid mammal Henkelotherium guimarotae from high‐resolution computed tomography and three‐dimensional imaging analysis. This study of Henkelotherium revealed a combination of derived and primitive features, including: cladotherian apomorphies, such as the promontorial sulcus for the internal carotid artery and reduced lateral trough; trechnotherian characters, such as an enclosed cochlear canaliculus for the perilymphatic duct, post‐promontorial tympanic sinus and caudal tympanic process; in addition to plesiomorphic mammalian features, such as the cavum supracochleare and prootic canal. The inner ear of Henkelotherium shows a division between the utricle and saccule, a cochlear canal coiled through at least 270°, a distinctive primary bony lamina for the basilar membrane, and a secondary bony lamina. The development of the primary and secondary bony laminae in the cochlear canal is suggested here to be correlated with the concurrent coiling of the bony canal and membranous duct of the inner ear cochlea, apomorphies of the more inclusive cladotherian clade that also represent the ancestral morphotype of modern therian mammals. Because these features are crucial for high‐frequency hearing in extant therian mammals, their early appearance in Late Jurassic cladotherians suggests a more ancient origination for high‐frequency hearing in mammalian history than previously thought.
Evolution of M1 crown size and cusp proportions in the genus Homo
Authors: Quam Rolf , Bailey Shara , Wood Bernard 
Published: April 2009

AbstractPrevious research into tooth crown dimensions and cusp proportions has proved to be a useful way to identify taxonomic differences in Pliocene and Pleistocene fossil hominins. The present study has identified changes in both M1 crown size and cusp proportions within the genus Homo, with M1 overall crown size reduction apparently occurring in two main stages. The first stage (a reduction of ca. 17%) is associated with the emergence of Homo ergaster and Homo erectus sensu stricto. The second stage (a reduction of ca. 10%) occurs in Homo sapiens, but the reduced modern human M1 tooth crown size was only attained in Upper Paleolithic times. The absolute sizes of the individual cusps are highly positively correlated with overall crown size and dental reduction produces a reduction in the absolute size of each of the cusps. Most of the individual cusps scale isometrically with crown size, but the paracone shows a negative allometric relationship, indicating that the reduction in paracone size is less than in the other M1 cusps. Thus, the phylogenetically oldest cusp in the upper molars also seems to be the most stable cusp (at least in the M1). The most striking change in M1 cusp proportions is a change in the relative size of the areas of the paracone and metacone. The combination of a small relative paracone and a large relative metacone generally characterizes specimens attributed to early Homo, and the presence of this character state in Australopithecus and Paranthropus suggests it may represent the primitive condition for the later part of the hominin clade. In contrast, nearly all later Homo taxa, with the exception of Homo antecessor, show the opposite condition (i.e. a relatively large paracone and a relatively small metacone). This change in the relationship between the relative sizes of the paracone and metacone is related to an isometric reduction of the absolute size of the metacone. This metacone reduction occurs in the context of relative stability in the paracone as crown size decreases. Among later Homo taxa, both Homo heidelbergensis and Homo neanderthalensis show a further reduction of the metacone and an enlargement of the hypocone. Fossil and contemporary H. sapiens samples show a trend toward increasing the relative size of the protocone and decreasing the relative size of the hypocone. In Europe, modern human M1 cusp proportions are essentially reached during the Upper Paleolithic. Although some variation was documented among the fossil taxa, we suggest that the relative size of the M1 paracone and metacone areas may be useful for differentiating the earliest members of our genus from subsequent Homo species.
Morphological and immunocytochemical characteristics indicate the yield of early progenitors and represent a quality control for human mesenchymal stem cell culturing
Authors: Haasters Florian , Prall Wolf Christian , Anz David , Bourquin Carole , Pautke Christoph , Endres Stefan , Mutschler Wolf , Docheva Denitsa , Schieker Matthias 
Published: April 2009

AbstractHuman mesenchymal stem cells (hMSC) are a heterogeneous cell population, which is reflected in varying morphological and biological properties. Three subpopulations with intrinsic characteristics can be distinguished: small rapidly self‐renewing cells, spindle‐shaped cells and large, flattened cells. Unfortunately, it has neither been possible to morphologically define these distinct cells consistently, nor to relate them to specific surface marker features. Here, the primary hMSC subpopulations of three donors are clearly defined by maximum cell diameter and area. Furthermore, these cells were stained for the putative hMSC surface markers CD105, CD90 as well as CD73, and evaluated by three‐colour flow cytometry and simultaneous multicolour immunocytochemistry. Interestingly, cell cultures with a high rate of triple‐positive hMSC featured a higher content of rapidly self‐renewing cells. On the other hand, a higher fraction of flattened cells correlated with a loss of one or more hMSC surface markers. The expression of CD73 showed the highest heterogeneity. Immunocytochemistry further confirmed that flattened cells mainly lack CD73 expression, whereas rapidly self‐renewing cells were steadily positive for all three hMSC markers. In the literature, hMSC properties are especially conceded to rapidly self‐renewing cells, whereas flattened cells have been suggested to represent early stages of lineage‐specific progenitors. We reveal that among the recently suggested surface markers, CD73 is the most sensitive, as it seems to be down‐regulated in the early stages of differentiation. Our morphological and immunocytochemical characterization of hMSC subpopulations indicates the yield of early multipotent hMSC and thereby provides a quality control approach for hMSC culturing.
From fish to modern humans – comparative anatomy, homologies and evolution of the pectoral and forelimb musculature
Authors: Diogo R. , Abdala V. , Aziz M. A. , Lonergan N. , Wood B. A. 
Published: April 2009

AbstractIn a recent study Diogo & Abdala [(2007) J Morphol 268, 504–517] reported the results of the first part of a research project on the comparative anatomy, homologies and evolution of the pectoral muscles of osteichthyans (bony fish and tetrapods). That report mainly focused on actinopterygian fish but also compared these fish with certain non‐mammalian sarcopterygians. This study, which reports the second part of the research project, focuses mainly on sarcopterygians and particularly on how the pectoral and forelimb muscles have evolved during the transitions from sarcopterygian fish and non‐mammalian tetrapods to monotreme and therian mammals and humans. The data obtained by our own dissections of all the pectoral and forelimb muscles of representative members of groups as diverse as sarcopterygian fish, amphibians, reptiles, monotremes and therian mammals such as rodents, tree‐shrews, colugos and primates, including humans, are compared with the information available in the literature. Our observations and comparisons clearly stress that, with regard to the number of pectoral and forelimb muscles, the most striking transition within sarcopterygian evolutionary history was that leading to the origin of tetrapods. Whereas extant sarcopterygian fish have an abductor and adductor of the fin and a largely undifferentiated hypaxial and epaxial musculature, extant salamanders such as Ambystoma have more than 40 pectoral and forelimb muscles. There is no clear increase in the number of pectoral and forelimb muscles within the evolutionary transition that led to the origin of mammals and surely not to that leading to the origin of primates and humans.
Immunohistochemical localization of Clara cell secretory proteins (CC10‐CC26) and Annexin‐1 protein in rat major salivary glands
Authors: Cecchini Maria Paola , Merigo Flavia , Cristofoletti Mirko , Osculati Francesco , Sbarbati Andrea 
Published: April 2009

AbstractThe oral cavity is continuously bathed by saliva secreted by the major and minor salivary glands. Saliva is the first biological medium to confront external materials that are taken into the body as part of food or drink or inhaled volatile substances, and it contributes to the first line of oral defence. In humans, it has been shown that sputum and a variety of biological fluids contain Clara cell secretory proteins (CC10–CC26). Various studies of the respiratory apparatus have suggested their protective effect against inflammatory response and oxidative stress. Recently, CC10 deficiency has been related to the protein Annexin‐1 (ANXA1), which has immunomodulatory and anti‐inflammatory properties. Considering the defensive role of both Clara cell secretory proteins and ANXA1 in the respiratory apparatus, and the importance of salivary gland secretion in the first line of oral defence, we decided to evaluate the expression of CC10, CC26 and ANXA1 proteins in rat major salivary glands using immunohistochemistry. CC10 expression was found only in the ductal component of the sublingual gland. Parotid and submandibular glands consistently lacked CC10 immunoreactivity. In the parotid gland, both acinar and ductal cells were always CC26‐negative, whereas in the submandibular gland, immunostaining was localized in the ductal component and in the periodic acid Schiff (PAS)‐positive area. In the sublingual gland, ductal cells were always positive. Acinar cells were not immunostained at all. ANXA1 was expressed in ductal cells in all three major glands. In parotid and sublingual glands, acinar cells were negative. In submandibular glands, immunostaining was present in the mucous PAS‐positive portion, whereas serous acinar cells were consistently negative. The existence of some CC10‐CC26–ANXA1‐positive cells in rat salivary glandular tissue is an interesting preliminary finding which could support the hypothesis, suggested for airway tissue, that these proteins have a defensive and protective role. Protein expression heterogeneity in the different portions of the glands could be an important clue in further investigations of their role.