bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of increasing population size and vegetation productivity on elephant distribution in the Kruger National Park
Authors: YOUNG KIM D. , FERREIRA SALAMON M. , Van AARDE RUDOLPH J. 
Published: March 2009

AbstractDecisions to reduce the impacts of large herbivores on biodiversity in protected areas are often based on controlling their numbers. However, numbers per se may not be the foremost consideration when managing impacts. This is because density‐related changes in distribution can also affect habitat utilization and hence, impact. In this study we tested whether changes in the distribution of African elephants are associated with increasing population size. We used spatially explicit count data collected during the dry seasons from 1998 to 2004 in South Africa's Kruger National Park. We did this at five spatial scales and in landscapes defined by vegetation, geology, climate and soils. We then investigated whether observed distributions and grid‐cell‐specific densities were associated with the remotely sensed Normalized Difference Vegetation Index (NDVI) as a measure of productivity and therefore food resource availability at the landscape scale. Consistent with density mediated changes, we found that elephant grid‐cell occupancy increased with population size, while grid‐cell‐specific density became less variable. In addition, the combined distribution of bull groups and breeding herds became less clumped with increasing population size. We further found that within landscapes elephants were present on grid‐cells with higher NDVI values, but that the influence of NDVI during the dry season on densities among landscapes may be weak. These results suggest that NDVI was more indicative of structural habitat choices such as woody vegetation than food availability per se. Our study highlights the need to consider factors other than population size alone when formulating management decisions to reduce large herbivore impacts on biodiversity in protected areas.
Flooding and grazing promote germination and seedling establishment in the perennial grass Paspalum dilatatum
Authors: CORNAGLIA PATRICIA S. , SCHRAUF GUSTAVO E. , DEREGIBUS V. ALEJANDRO 
Published: March 2009

AbstractSeed germination and seedling emergence are key processes for population recruitment. Flooding and grazing are disturbances forming gaps that may strongly influence recruitment patterns in space and time, but their combined effects and action mechanisms have rarely been addressed. In this study we analysed the effects of microhabitat conditions associated with winter flooding and spring‐summer defoliation on seed germination and seedling establishment of Paspalum dilatatum, a dominant perennial C4 grass in native grasslands of the Flooding Pampa, Argentina. The dynamics of seedling emergence from natural seed banks and buried seeds was studied in a factorial experiment with flooding and defoliation treatments applied to soil monoliths (mesocosms) collected from natural grassland. Additional laboratory experiments were applied to investigate seed germination under different combinations of temperature, light quality and simulated flooding. Seed germination and seedling emergence of P. dilatatum were promoted by flooding and high intensity defoliation. Gaps generated by flooding were maintained by high intensity defoliation exercising a synergistic effect on survival seedlings. Flooding resulted in the breaking of seed dormancy and higher germination rates associated with alternating temperature and the activation of the phytochrome system. Our results indicate that microhabitat conditions associated with the disturbances forming gaps, such as flooding and heavy grazing, synergistically promote the recruitment process of this dominant grass species.
Vehicle fatigue damage caused by road irregularities
Authors: BOGSJÖ K. , RYCHLIK I. 
Published: March 2009

ABSTRACTRoad roughness causes fatigue‐inducing loads in travelling vehicles. Road sections with a high degree of roughness are of special interest because these have a significant impact on vehicle's fatigue life. This study is focused on the statistical description and analysis of vehicle damage caused by irregularities. Standard statistical analysis tools are not straightforwardly applicable because of the non‐stationary property of the irregularities. However, it is found that the road irregularities' influence on vehicles can be accurately described using a ‘local’ narrow‐band approximation of the fatigue damage intensity.
Changes in alternative brain‐derived neurotrophic factor transcript expression in the developing human prefrontal cortex
Authors: Wong Jenny , Webster Maree J. , Cassano Hope , Weickert Cynthia S. 
Published: March 2009

AbstractIn this study, we determined when and through which promoter brain‐derived neurotrophic factor (BDNF) transcription is regulated during the protracted period of human frontal cortex development. Using quantitative real‐time polymerase chain reaction, we examined the expression of the four most abundant alternative 5′ exons of the BDNF gene (exons I, II, IV, and VI) in RNA extracted from the prefrontal cortex. We found that expression of transcripts I–IX and VI–IX was highest during infancy, whereas that of transcript II–IX was lowest just after birth, slowly increasing to reach a peak in toddlers. Transcript IV–IX was significantly upregulated within the first year of life, and was maintained at this level until school age. Quantification of BDNF protein revealed that levels followed a similar developmental pattern as transcript IV–IX. In situ hybridization of mRNA in cortical sections showed the highest expression in layers V and VI for all four BDNF transcripts, whereas moderate expression was observed in layers II and III. Interestingly, although low expression of BDNF was observed in cortical layer IV, this BDNF mRNA low‐zone decreased in prominence with age and showed an increase in neuronal mRNA localization. In summary, our findings show that dynamic regulation of BDNF expression occurs through differential use of alternative promoters during the development of the human prefrontal cortex, particularly in the younger age groups, when the prefrontal cortex is more plastic.
Differential representation of Pavlovian–instrumental transfer by prefrontal cortex subregions and striatum
Authors: Homayoun Houman , Moghaddam Bita 
Published: March 2009

AbstractEnvironmental cues that once predicted reward can restore extinguished behavior directed toward that reward. This process may be modeled by the Pavlovian–instrumental transfer (PIT) paradigm where a previously learned Pavlovian conditioned stimulus (CS) elicits a representation of the reward associated with that CS, prompts motivation toward the absent reward, and triggers an instrumental action. We recorded in the medial and orbital prefrontal cortex (mPFC and OFC) and dorsal striatum (DS) of freely moving rats during PIT and found that a Pavlovian CS, as compared with neutral or no stimuli, amplified the phasic neuronal responses to instrumental nosepokes (‘transfer’ event). In mPFC and OFC, but not the DS, representation of the transfer event correlated with the strength of PIT behavior. Neurons in all three regions showed CS‐selective amplification of Pavlovian approaches toward the reward delivery site. Whereas striatal neurons represented transfer and approach behavior through mostly segregated neuronal subsets, overlapping subsets represented these events in the mPFC and OFC. These findings suggest that parallel phasic activation of mPFC and OFC neuronal subsets participates in the transfer from Pavlovian incentives to instrumental actions.
The natriuretic effect of oxytocin blocks medial tuberomammillary polydipsia and polyuria in male rats
Authors: Mahía Javier , Bernal Antonio , García del Rio C. , Puerto Amadeo 
Published: March 2009

AbstractLesions of the tuberomammillary complex, a neuroanatomical system closely related to the hypothalamic supraoptic and paraventricular nuclei, induce strong polydipsia in male rats. It was recently demonstrated that this increase in water intake is immediate, persistent, follows circadian rhythms and appears to be related to sodium regulation. The present study found that urine osmolality was significantly lower in tuberomammillary‐lesioned animals vs. their respective controls at 8:00 h after surgery. Therefore, the aim of the present study was to examine the natriuretic effect of intraperitoneal oxytocin (OT) administration on medial ventral tuberomammillary nucleus (E3) polydipsia and polyuria of lesioned and control male rats. At 24:00 h post‐lesion, OT blocked the hyperdipsic and polyuric responses of E3‐lesioned animals but not those of non‐lesioned controls, which did however significantly increase their water intake. Moreover, urinary osmolality and sodium excretion increased in E3 ‐lesioned animals that received OT but not in lesioned controls receiving physiological saline (992 ± 187.19 vs. 215.83 ± 23.39 mOsm/kg; 1.68 ± 0.13 vs. 0.47 ± 0.1 mEq/L). At 48:00 h post‐lesion, OT administration also induced a higher intake of water and of simultaneously offered hypertonic NaCl (1.5%) in E3‐lesioned animals. These results are interpreted in terms of the hypothalamic systems involved in sodium and water homeostasis.
Why the Rigour–Relevance Gap in Management Research Is Unbridgeable
Authors: Kieser Alfred , Leiner Lars 
Published: March 2009

abstractIn this paper we discuss, on the basis of system theory, the rigour–relevance gap in management research and the proposal to overcome it. From a system theory perspective, social systems are self‐referential or autopoietic, which means that communication elements of one system, such as science, cannot be authentically integrated into communication of other systems, such as the system of a business organization. Social systems can only irritate – provoke – each other, i.e. alter conditions in such a way that other systems are forced to respond. Because of the differences between management science and practice it is impossible to assess relevance of research output within the system of science. On the basis of our analysis we show that neither action research nor Mode 2 research nor recent approaches to collaborative research can succeed in producing research that is rigorous as well as relevant. Researchers and practitioners cannot collaboratively produce research, they can only irritate each other. However, sometimes irritations or provocations turn out inspiring.
TopoPlan: a topological path planner for real time human navigation under floor and ceiling constraints
Authors: Lamarche F. 
Published: March 2009

AbstractIn this article we present TopoPlan, a topological planner dedicated to real‐time humanoid path‐planning and motion adaptation to floor and ceiling constraints inside complex static environments. This planner analyzes unstructured 3D triangular meshes in order to automatically determine their topology. The analysis is based on a prismatic spatial subdivision which is analyzed, taking into account humanoid characteristics, in order to extract navigable surfaces and precisely identify environmental constraints such as floors, ceilings, walls, steps and bottlenecks. The technique also provides a lightweight roadmap computation covering all accessible free space. We demonstrate the properties of our topological planner within the context of two reactive motion control processes: an on‐the‐fly trajectory optimization and foot print generation process that correctly handles climbing of complex staircases, and a reactive ceiling adaptation process that handles beam avoidance and motion adaptation to irregular floors and ceilings. We further show that the computation cost of these processes is compatible with the real time animation of several dozens of virtual humans.
Example‐Based Rendering of Eye Movements
Authors: Banf Michael , Blanz Volker 
Published: March 2009

AbstractThis paper describes a model for example‐based, photo‐realistic rendering of eye movements in 3D facial animation. Based on 3D scans of a face with different gaze directions, the model captures the motion of the eyeball along with the deformation of the eyelids and the surrounding skin. These deformations are represented in a 3D morphable model.Unlike the standard procedure in facial animation, the eyeball is not modeled as a rotating 3D sphere located behind the skin surface. Instead, the visible region of the eyeball is part of a continuous face mesh, and displacements of the iris as well as occlusions by the lids are modeled in a texture mapping approach. The algorithm avoids artifacts that are widely encountered in 3D facial animation, and it presents a new concept of handling occlusions and discontinuities in morphing algorithms.
Does Export Openness Increase Firm‐level Output Volatility?
Authors: Buch Claudia M. , Döpke Jörg , Strotmann Harald 
Published: March 2009

AbstractThere is a widespread concern that increased trade may lead to increased instability and thus risk at the firm level. Greater export openness can indeed affect firm‐level volatility by changing the exposure and the reaction of firms to macroeconomic developments. The net effect is ambiguous from a theoretical point of view. This paper provides firm‐level evidence on the link between openness and volatility. Using comprehensive data on more than 21,000 German manufacturing firms for the period 1980–2001, we analyse the evolution of firm‐level output volatility and the link between volatility and export openness. Our paper has three main findings. First, firm‐level output volatility is significantly higher than the level of aggregate volatility, but it displays similar patterns. Second, increased export openness lowers firm‐level output volatility. This effect is primarily driven by variations along the extensive margin, i.e. by the distinction between exporters and non‐exporters. Variations along the intensive margin, i.e. the volume of exports, tend to have a dampening impact on volatility as well. Third, small firms are more volatile than large firms.
Tumefactive demyelinating disease treated with decompressive craniectomy
Authors: Nilsson P. , Larsson E.‐M. , Kahlon B. , Nordström C.‐H. , Norrving B. 
Published: March 2009

Background:  Tumefactive demyelinating disease (TDD) is a rare primary demyelinating disease with diagnostic and therapeutic challenges.Methods and results:  We report a 50‐year old woman with TDD successfully treated with decompressive craniectomy and corticosteroids. The patient presented with seizures, subacute progressive hemispheric syndrome, and a tumourlike abnormality on MRI. Demyelinating disease was initially considered unlikely. Due to a rapidly evolving herniation syndrome hemicraniectomy was performed. Outcome was favourable with only very mild neurological deficits 6 weeks later.Conclusion:  TDD should be considered as a differential diagnosis in tumour‐like presentations, and appears to have distinctive neuroimaging features. In the advent of treatement failure from high dose corticosteroids and plasmapheresis and development of severe mass effect, decompressive hemicraniectomy is an important treatment option.
What are we saving? Developing a standardized approach for conservation action
Authors: Sitas N. , Baillie J. E. M. , Isaac N. J. B. 
Published: March 2009

AbstractAre all species equal in terms of conservation attention? We developed a novel framework to assess the level of conservation attention given to 697 threatened mammals and 100 critically endangered amphibian species. Our index of conservation attention provides a quantitative framework for assessing how conservation resources are allocated, based on the degree to which conservation interventions have been proposed and implemented. Our results provide evidence of the strong biases in global conservation attention. We find that most threatened species receive little or no conservation, and that the small number receiving substantial attention is extremely biased. Species most likely to receive conservation attention are those which are well‐studied, charismatic and that live in the developed world. Conservation status and evolutionary distinctiveness appear to have little importance in conservation decision‐making at the global scale. Most species inhabit the tropics and are both poorly known and uncharismatic. Therefore, the majority of biodiversity is being ignored by current conservation action.
Functional aspects of the mucus‐producing glands of the Systellommatophoran slug, Veronicella floridana
Authors: COOK ANTHONY 
Published: March 2009

The mucus‐producing glands of the tropical slug Veronicella floridana Leidy were examined histochemically. The bulk of the dorsal mucus is a carboxylated mucopolysaccharide produced by deeply embedded gland cells which contribute to inflated common ducts. Little mucus is apparent on the dorsal surface of an unirritated slug, giving the dorsal aspect of the animal a dry appearance. Measurements of the rate of water loss of whole animals indicate that water is lost significantly more slowly than from the equivalent area of water.The foot possesses regular transverse ridges and the pedal mucus is produced largely by a set of gland cells associated with each ridge. This mucus is a mixture of mucopolysaccharides and protein. The suprapedal gland which also contributes to the pedal mucus is extremely small and produces a weakly acidic and neutral mucopolysaccharide and a protein. There is no specialization in the leading edge of the foot and no Semper's organ. The cleft between the foot and the body is unciliated and bears few specialized gland cells.Compared with the mucus produced by Limax pseudoflavus, the pedal mucus of Veronicella is of comparable function and composition though produced by glands of different derivations. The dorsal mucus is histochemically different from that of Limax though similar in physical appearance. Whilst the dorsal mucus of Limax is freely distributed over exposed surfaces, that of Veronicella is held in reserve in inflated ducts resulting in a dry leathery appearance and a depressed rate of water loss.
Phylogenetic aspects of tooth and jaw structure of the Medaka, Oryzias latipes, and other beloniform fishes
Authors: PARENTI LYNNE R. 
Published: March 2009

Tooth structure is described for adult male, female, and juvenile Oryzias latipes (Temminck & Schlegel), the Medaka. Adult males have enlarged, unicuspid teeth posteriorly on the premaxilla and dentary. Oral teeth are smaller and more numerous in females, in which no tooth is notably larger than the others. Juveniles have numerous small teeth from about 3 mm SL (standard length) onwards. By about 16 mm SL, males begin to develop the large posterior teeth, as well as other secondary sexual characters. Lower and upper pharyngeal teeth of both males and females are fine, and in numerous even rows.The large, posterior oral teeth of males are fully‐ankylosed to the attachment bone, and, hence, are not depressible. In female Medaka, as in the Halfbeak Dermogenys pusillus van Hasselt, the oral teeth have a ring of unmineralized collagen at the base, and are not depressible. Pharyngeal teeth of Medaka have a ring of unmineralized collagen at the base, and a distinct wedge of collagen absent posteriorly, such that the pharyngeal teeth may be depressed.Bone in adult Medaka is acellular. Incompletely mineralized teeth, acellular bone, a protrus‐ible upper oral jaw, and a mobile branchial apparatus with an interhyal bone, form a complex characteristic of advanced teleosts. The Medaka differs in several ways from the model advanced teleost: absence of an interhyal bone, ascending and articular processes of the premaxilla, and the rostral cartilage, as well as presence of cartilaginous symphyses between the dentaries and premaxillae, all contribute to the fixed or nonprotrusible jaws.Reduction in the premaxilla is a derived character within beloniform fishes for which an enlarged, beaked outer jaw is considered plesiomorphic.
Ecology of an Indian grassland millipede Streptogonopus phipsoni (Diplopoda: Polydesmoidea)
Authors: Bhakat Som Nath 
Published: March 2009

Each of stadia II‐VII and adults (stadia VIII) of Streptogonopus phipsoni (Pocock) can be distinguished by segment numbers, length, breadth and paired legs. Sexes are separate from stadium IV and sex ratios in immature stages were more or less 50% throughout the year, but high proportions of adult females are noted from June to September. High ratios of immature to adult were related to the breeding periods, from May to October, and in other months adults increased in proportion as a result of heavy mortality of immatures.Adults were aggregated in distribution from April to October while solitary individuals were common in other months of the year.Population density of S. phipsoni varied from 0.25 to 98 m‐2 on the soil surface and 1 to 11.75 m‐2 in the lower layer (0–7 cm deep). Biomass ranged from 12.25 to 2253 mg‐2 on the surface and 50.75 to 424.75 mg‐2 in the lower layer (0–7 cm deep).A positive and significant correlation was found between mean monthly population density and mean monthly rainfall. Streptogonopus phipsoni appears to complete its life cycle in one or two years
The ovarian cycle and control of ovulation
Authors: Hodges J. K. 
Published: March 2009

The ovarian cycle of primates is a sequence of events reflecting follicular growth and development, the ovulation of a mature oocyte and the formation of a functional corpus luteum. A typical cycle generally consists of three phases: (1) the follicular or proliferative phase, (2) ovulation and (3) the luteal or secretory phase. Within this general pattern exists considerable species variation in terms of cycle length, timing of ovulation, presence or absence of menstruation and influence of season.Details of the basic physiological mechanisms controlling cyclic ovarian function in primates are known for only a few species. Concentrating on information derived from studies in women and in rhesus and marmoset monkeys, this paper examines some of the hormonal mechanisms underlying the primate ovarian cycle with particular reference to the factors controlling preovulatory follicular development during the follicular phase.
Social organization in the pheasant (Phasianus colchicus): harem formation, mate selection and the role of mate guarding
Authors: RIDLEY M. W. , HILL D. A. 
Published: March 2009

Harem formation and mate selection were studied in the pheasant in order to determine the advantages of territorial harem defence polygyny to the two sexes. We investigated the factors affecting harem size and the advantage to a female in remaining with one territorial male during breeding.Female group size declined during late March and early April as females moved from large overlapping ranges into smaller, more widely dispersed breeding ranges. The proportion of female groups accompanied by males increased during this period.Some males had a disproportionate share of females. Settled females were monogamous but, because a female's nest was generally outside the male's territory, her home range was larger than his territory.Harem members were usually from the same winter group. Harem size was not related to territory quality in terms of food supply or nesting cover. Females were loyal to one male in more than one year even if his territory position changed. Older, territory‐owning males had more females, both adult and immature, than males with newly‐established territories. Harem size was not correlated with territory size.We conclude that the mating system of the pheasant is based on mate guarding which protects females not only from the risk of predation or injury, but also from excessive energy expenditure incurred through being chased by other males. When escorted by a territorial male, females spent three times as much time feeding, one‐fifth as much time running, and one‐tenth as much time alert, as they did when not guarded.