877 research outputs found
Elephant cognition in primate perspective
On many of the staple measures of comparative psychology, elephants show no obvious differences from other mammals, such as primates: discrimination learning, memory, spontaneous tool use, etc. However, a range of more naturalistic measures have recently suggested that elephant cognition may be rather different. Wild elephants sub-categorize humans into groups, independently making this classification on the basis of scent or colour. In number discrimination, elephants show no effects of absolute magnitude or relative size disparity in making number judgements. In the social realm, elephants show empathy into the problems faced by others, and give hints of special abilities in cooperation, vocal imitation and perhaps teaching. Field data suggest that the elephantâs vaunted reputation for memory may have a factual basis, in two ways. Elephantsâ ability to remember large-scale space over long periods suggests good cognitive mapping skills. Elephantsâ skill in keeping track of the current locations of many family members implies that working memory may be unusually developed, consistent with the laboratory finding that their quantity judgements do not show the usual magnitude effects.Publisher PDFPeer reviewe
Floral display and habitat fragmentation: Effects on the reproductive success of the threatened massâflowering Conospermum undulatum (Proteaceae)
Fragmentation of natural vegetation is currently one of the largest threats to plant populations and their interactions with pollinators. Plant reproductive susceptibility to habitat fragmentation has been investigated in many species; however, the response of wild massâflowering species is poorly known, with research limited to mainly boreal plant species. Here, we studied twelve remnant populations of the threatened massâflowering shrub Conospermum undulatum in the southwest Australian biodiversity hotspot, each presenting different population size, level of isolation, and floral display. We assessed the impact of fragmentation on (a) fruit and seed production; and (b) seed germination. To gain a deeper understanding of factors influencing the reproductive success of C. undulatum, we performed pollinator exclusion and selfâpollination treatments to experimentally assess the mating system of this threatened shrub. We found C. undulatumto be strictly selfâincompatible and totally reliant on pollinators visiting with an outcrossed pollen load to complete the reproductive cycle. Further, we found that fruit production dropped from 35% to Synthesis and applications. Our results demonstrate the important relationship between pollinators and floral morphology in plants of southwest Australia that have coevolved with native pollinators and developed characteristic flower morphologies over long time frames. Indeed, due to its characteristic pollination mechanism, the selfâincompatible C. undulatum can only rely on specialized native pollinators for pollen flow and cannot rely on its massâflowering trait to attract generalist pollinators from coflowering species; neither can it compensate for the lack of visitors by promoting geitonogamy. Consequently, fragmentation has a significant effect on the reproductive output of C. undulatum, and size, isolation, and floral display of populations are important factors to be considered when planning conservation actions for the species
Early Career Experiences of Pediatricians Pursuing or Not Pursuing Fellowship Training
BACKGROUND AND OBJECTIVES: Choosing career paths can be difficult decisions for residents contemplating fellowship training. This study compares the experiences of early career pediatricians who did and did not pursue fellowships.
METHODS: We analyzed national, weighted data from pediatricians 8 to 10 years after residency (n = 842). Work environment, workâlife balance, and satisfaction were compared for pediatricians who had pursued fellowship training (fellowship trained) and those who did not pursue fellowship training (generalist trained). Logistic and linear regression examined the independent effects of fellowship training while controlling for demographic differences.
RESULTS: A total of 39% of the pediatricians (328/842) pursued fellowship training. The fellowship-trained group was less likely than the generalist-trained group to spend time in direct patient care and more likely to report learning opportunities in their work environment. This group was also more likely to report an income of â„$150â000, although no difference was found when only full-time pediatricians were examined. Generalist-trained pediatricians were more likely to work <50 hours per week, have flexibility with their schedules, and be satisfied with time spent with their own children. Pediatricians in both the fellowship-trained and generalist-trained groups generally found their work to be rewarding and were satisfied with their lives.
CONCLUSIONS: Although residents need to consider important life and career differences when contemplating fellowship training and general care, pediatricians in both groups can achieve overall life and career satisfaction
A comparison of the solvation power of the green solvent 2,2,5,5-tetramethyloxolane versus toluene via partition coefficients
2,2,5,5-tetramethyloxolane [previously published as 2,2,5,5-tetramethyltetrahydrofuran (TMTHF)] has recently been demonstrated as a greener and cleaner alternative to toluene in several applications. Assessing similarities in properties of toluene and 2,2,5,5-tetramethyloxolane is crucial for establishing this molecules potential to replace traditional non-polar organic solvents in the cleaner production of chemicals and materials. However, the Hansen solubility parameters (HSP) and Kamlet-Taft parameters (KT) give conflicting views on their similarities and differences, which necessitates a full comparative characterisation of the solvation environment of these two solvents. Such comparisons have been achieved through a direct and extensive determination of partition coefficients between each of the two solvents and water. The partition coefficients and Abraham's solvation parameter model have quantitatively clarified the similarities and differences in properties of 2,2,5,5-tetramethyloxolane and toluene. Solutes of high dipolarity and hydrogen-bond accepting ability tended to favour the aqueous phase in both systems, while large molar volume and high refractive indices favoured the organic phase. A significant difference between 2,2,5,5-tetramethyloxolane and toluene was observed for hydrogen-bond donating solutes. In general, such solutes strongly preferred the aqueous phase in the toluene/water system but preferred the organic phase in the 2,2,5,5-tetramethyloxolane/water system. This was due to the interaction of the protic solutes with the lone pairs of electrons on the ethereal oxygen of 2,2,5,5-tetramethyloxolane, a feature that is not present on toluene, and opens up new possibilities for applications of this sustainable solvent in liquid-liquid extraction, particularly in the isolation of natural products. As toluene is such an important solvent in the chemical industry, its replacement with a greener alternative such as 2,2,5,5-tetramethyloxolane would be hugely significant for cleaner synthesis, extractions and separations
Isolation, characterization, and crossâamplification of 20 microsatellite markers for Conospermum undulatum (Proteaceae)
PREMISE: Recent habitat fragmentation is posing a risk to the wavyâleaved smokebush, Conospermum undulatum (Proteaceae), a rare plant species endemic to southwestern Western Australia. Microsatellite markers are required to characterize the genetic diversity and structure of the species for conservation purposes and to facilitate ecological studies.
METHODS AND RESULTS: Illumina MiSeq highâthroughput sequencing was used to develop 20 novel microsatellite markers for C. undulatum. Polymorphism at each locus was assessed using 72 individuals from three natural populations. Nineteen markers were polymorphic, with the number of alleles per locus ranging from two to 21, and observed and expected heterozygosity ranging from 0.000 to 1.000 and 0.117 to 0.919, respectively. All markers successfully amplified in three congeneric species (C. stoechadis, C. canaliculatum and C. triplinervium).
CONCLUSIONS: The microsatellite markers will be useful for revealing patterns of genetic diversity, dispersal dynamics, and hybridization events for C. undulatum to inform future conservation efforts
Rhabdomyolysis After Laparoscopic Nephrectomy
BACKGROUND AND OBJECTIVES: Laparoscopic renal surgery has become a widely applied technique in recent years. The development of postoperative rhabdomyolysis is a known but rare complication of laparoscopic renal surgery. Herein, 4 cases of rhabdomyolysis and a review of the literature are presented with respect to pathogenesis, treatment, and prevention of this dire complication. METHODS: A retrospective review of over 600 laparoscopic renal operations over the past 8 years was performed. All cases of postoperative rhabdomyolysis were identified. A Medline search was performed to find articles related to the development of postoperative rhabdomyolysis. Cases of rhabdomyolysis developing after laparoscopic renal surgery and common risk factors between cases were identified. RESULTS: The incidence of postoperative rhabdomyolysis in our series is 0.67%. It is similar to the rate reported in other series. Male sex, high body mass index, prolonged operative times, and the lateral decubitus position are all risk factors in its development. CONCLUSION: The prevention and optimal management of postoperative rhabdomyolysis following laparoscopic renal surgery has yet to be defined. The risk factors we identified should be carefully addressed and minimized. A better understanding of the pathogenesis of rhabdomyolysis will also be a key component in its prevention
A multiple scale model for tumor growth
We present a physiologically structured lattice model for vascular tumor growth which accounts for blood flow and structural adaptation of the vasculature, transport of oxygen, interaction between cancerous and normal tissue, cell division, apoptosis, vascular endothelial growth factor release, and the coupling between these processes. Simulations of the model are used to investigate the effects of nutrient heterogeneity, growth and invasion of cancerous tissue, and emergent growth laws
- âŠ