A temporal dimension to the influence of pollen rewards on bee behaviour and fecundity in Aloe tenuior

The net effect of pollen production on fecundity in plants can range from negative – when self-pollen interferes with fecundity due to incompatibility mechanisms, to positive – when pollen availability is associated with increased pollinator visitation and fecundity due to its utilization as a reward. We investigated the responses of bees to pollen and nectar rewards, and the effects of these rewards on pollen deposition and fecundity in the hermaphroditic succulent shrub Aloe tenuior. Self-pollinated plants failed to set fruit, but their ovules were regularly penetrated by self-pollen tubes, which uniformly failed to develop into seeds as expected from ovarian self-incompatibility (or strong early inbreeding depression). Bees consistently foraged for pollen during the morning and early afternoon, but switched to nectar in the late afternoon. As a consequence of this differential foraging, we were able to test the relative contribution to fecundity of pollen- versus nectar-collecting flower visitors. We exposed emasculated and intact flowers in either the morning or late afternoon to foraging bees and showed that emasculation reduced pollen deposition by insects in the morning, but had little effect in the afternoon. Despite the potential for self-pollination to result in ovule discounting due to late-acting self-sterility, fecundity was severely reduced in artificially emasculated plants. Although there were temporal fluctuations in reward preference, most bee visits were for pollen rewards. Therefore the benefit of providing pollen that is accessible to bee foragers outweighs any potential costs to fitness in terms of gender interference in this species

How Much Does It Cost to Go Off-Grid with Renewables? A Case Study of a Polygeneration System for a Neighbourhood in Hermosillo, Mexico

As governments and companies struggle to meet their own objectives for the energy transition, more innovative social and technological measures are needed to reduce Greenhouse Gas (GHG) emissions. For this purpose, an assessment of an off-grid polygeneration system, which can serve the electric and cooling demand of a neighbourhood in Hermosillo, Mexico, has been conducted. Energy computations have been done, the energy demand of one dwelling has been measured to ascertain the correctness of the computations, and a demand model for the entire neighbour-hood has been created. Based on the model, an off-grid polygeneration system has been designed, which uses a biodiesel engine, PV panels, and an absorption chiller. The system has been optimized for its economic performance and is compared to the currently used system. The results show that the polygeneration system with higher energy efficiency could reduce GHG emissions down to 14%. However, electricity in Hermosillo is heavily subsidized making it harder for innovative systems to compete. Moreover, even without the state subsidies to the end-user, the polygeneration system has still a nearly 30% higher Net Present Cost (NPC) than the conventional system over its project lifetime of 20 years. Nonetheless, with precise political incentives and further advances in the applied technologies, small-scale renewable polygeneration systems could become cost-efficient alternatives in the near future.Postprint (author's final draft

Common carp (Cyprinus carpio L.) alters its feeding niche in response to changing food resources: direct observations in simulated ponds

We used customized fish tanks as model fish ponds to observe grazing, swimming, and conspecific social behavior of common carp (Cyprinus carpio) under variable food-resource conditions to assess alterations in feeding niche. Different food and feeding situations were created by using only pond water or pond water plus pond bottom sediment or pond water plus pond bottom sediment and artificial feeding. All tanks were fertilized twice, prior to stocking and 2 weeks later after starting the experiment to stimulate natural food production. Common carp preferred artificial feed over benthic macroinvertebrates, followed by zooplankton. Common carp did not prefer any group of phytoplankton in any treatment. Common carp was mainly benthic in habitat choice, feeding on benthic macroinvertebrates when only plankton and benthic macroinvertebrates were available in the system. In the absence of benthic macroinvertebrates, their feeding niche shifted from near the bottom of the tanks to the water column where they spent 85% of the total time and fed principally on zooplankton. Common carp readily switched to artificial feed when available, which led to better growth. Common carp preferred to graze individually. Behavioral observations of common carp in tanks yielded new information that assists our understanding of their ecological niche. This knowledge could be potentially used to further the development of common carp aquaculture

Mitochondrial dysfunction is an important cause of neurological deficits in an inflammatory model of multiple sclerosis

Neuroinflammation can cause major neurological dysfunction, without demyelination, in both multiplesclerosis (MS) and a mouse model of the disease (experimental autoimmune encephalomyelitis; EAE), but the mechanisms remain obscure. Confocal in vivo imaging of the mouse EAE spinal cord reveals that impaired neurological function correlates with the depolarisation of both the axonal mitochondria and the axons themselves. Indeed, the depolarisation parallels the expression of neurological deficit at the onset of disease, and during relapse, improving during remission in conjunction with the deficit. Mitochondrial dysfunction, fragmentation and impaired trafficking were most severe in regions of extravasated perivascular inflammatory cells. The dysfunction at disease onset was accompanied by increased expression of the rate-limiting glycolytic enzyme phosphofructokinase-2 in activated astrocytes, and by selective reduction in spinal mitochondrial complex I activity. The metabolic changes preceded any demyelination or axonal degeneration. We conclude that mitochondrial dysfunction is a major cause of reversible neurological deficits in neuroinflammatory disease, such as MS

Shifting Home Energy Consumption Through a Holistic Understanding of the Home System of Practice

This chapter describes the concept of the home system of practice, which can be used to provide a deeper understanding of the social system of the home and inform long-term solutions for enabling domestic energy reduction. More traditional methods have attempted to persuade occupants to change behaviour through the use of information campaigns and feedback technology. However, these interventions are usually short lived as they ignore the underlying reasons for practices to occur. A more effective solution is through practice-oriented design, which co-creates innovative technology with the user. In addition, the emergence and use of automated technology enables practices to act independently of the user. Yet, the success of automation is also reliant on an understanding of the home system of practice, occupant needs and skills

Distinct Mechanisms for Induction and Tolerance Regulate the Immediate Early Genes Encoding Interleukin 1β and Tumor Necrosis Factor α

Interleukin-1β and Tumor Necrosis Factor α play related, but distinct, roles in immunity and disease. Our study revealed major mechanistic distinctions in the Toll-like receptor (TLR) signaling-dependent induction for the rapidly expressed genes (IL1B and TNF) coding for these two cytokines. Prior to induction, TNF exhibited pre-bound TATA Binding Protein (TBP) and paused RNA Polymerase II (Pol II), hallmarks of poised immediate-early (IE) genes. In contrast, unstimulated IL1B displayed very low levels of both TBP and paused Pol II, requiring the lineage-specific Spi-1/PU.1 (Spi1) transcription factor as an anchor for induction-dependent interaction with two TLR-activated transcription factors, C/EBPβ and NF-κB. Activation and DNA binding of these two pre-expressed factors resulted in de novo recruitment of TBP and Pol II to IL1B in concert with a permissive state for elongation mediated by the recruitment of elongation factor P-TEFb. This Spi1-dependent mechanism for IL1B transcription, which is unique for a rapidly-induced/poised IE gene, was more dependent upon P-TEFb than was the case for the TNF gene. Furthermore, the dependence on phosphoinositide 3-kinase for P-TEFb recruitment to IL1B paralleled a greater sensitivity to the metabolic state of the cell and a lower sensitivity to the phenomenon of endotoxin tolerance than was evident for TNF. Such differences in induction mechanisms argue against the prevailing paradigm that all IE genes possess paused Pol II and may further delineate the specific roles played by each of these rapidly expressed immune modulators. © 2013 Adamik et al

The Spinal Cord Expression of Neuronal and Inducible Nitric Oxide Synthases and Their Contribution in the Maintenance of Neuropathic Pain in Mice

Background: Nitric oxide generated by neuronal (NOS1), inducible (NOS2) or endothelial (NOS3) nitric oxide synthases contributes to pain processing, but the exact role of NOS1 and NOS2 in the maintenance of chronic peripheral neuropathic pain as well as the possible compensatory changes in their expression in the spinal cord of wild type (WT) and NOS knockout (KO) mice at 21 days after total sciatic nerve ligation remains unknown. Methodology/Principal Findings: The mechanical and thermal allodynia as well as thermal hyperalgesia induced by sciatic nerve injury was evaluated in WT, NOS1-KO and NOS2-KO mice from 1 to 21 days after surgery. The mRNA and protein levels of NOS1, NOS2 and NOS3 in the spinal cord of WT and KO mice, at 21 days after surgery, were also assessed. Sciatic nerve injury led to a neuropathic syndrome in WT mice, in contrast to the abolished mechanical allodynia and thermal hyperalgesia as well as the decreased or suppressed thermal allodynia observed in NOS1-KO and NOS2-KO animals, respectively. Sciatic nerve injury also increases the spinal cord expression of NOS1 and NOS2 isoforms, but not of NOS3, in WT and NOS1-KO mice respectively. Moreover, the presence of NOS2 is required to increase the spinal cord expression of NOS1 whereas an increased NOS1 expression might avoid the up-regulation of NOS2 in the spinal cord of nerve injured WT mice. Conclusions/Significance: These data suggest that the increased spinal cord expression of NOS1, regulated by NOS2, might be responsible for the maintenance of chronic peripheral neuropathic pain in mice and propose these enzymes as interesting therapeutic targets for their treatment

Challenging Convention(s): Methodological Explorations in Contemporary Qualitative Inquiry

Based on a recent inaugural lecture, this article presents a critical appreciation and analysis of the application of different research methodologies to selected social and educational research contexts. The analysis is set against the backdrop of an ontological question concerning the possibility of truth. Specifically, it seeks to explore the untenability of any notion of absolute truth in contemporary qualitative inquiry, and examine the corollary implications for determining the nature, role and status of research. It is argued that the ability to challenge convention offers both the possibility and productive capacity to unsettle dominant research methodologies, while also critiquing normative social and professional research practices. Utilising three contrasting methodological frameworks: Gadamerian hermeneutics; Foucauldian theory; and Lacanian psychoanalytic theory; the narrative follows a journey of personal development and shows how seemingly different and diverse theoretical perspectives can reveal critical new insights on contemporary social research issues and practices, cultures and communities

Bringing CASE in from the cold: the teaching and learning of thinking

Thinking Science is a two-year program of professional development for teachers and thinking lessons for students in junior high school science classes. This paper presents research on the effects of Thinking Science on students’ levels of cognition in Australia. The research is timely with a general capability focused on critical thinking in the newly implemented F-10 curriculum in Australia. The design of the research was a quasi-experiment with pre and post-intervention cognitive tests conducted with participating students (n = 655) from nine cohorts in seven high schools. Findings showed significant cognitive gains compared with an age matched control group over the length of the program. Noteworthy, is a correlation between baseline cognitive score and school Index of Community Socio-Educational Advantage (ICSEA). We argue that the teaching of thinking be brought into the mainstream arena of educational discourse and the principles from evidence-based programs such as Thinking Science be universally adopted