What underlies the benefits of environmental enrichment on the brain? : investigation of a neurotrophin-stimulaed kinase reveals its role in regulating sociability and experience-dependent changes in hippocampal gene expression

Cognitive impairment, as a result of developmental issues, age and diseases such as dementia have the potential to affect anyone, and are a significant source of socioeconomic burden to both the healthcare system and the families of those affected. Environmental enrichment has emerged as a non-pharmacological intervention that can improve cognitive function and ameliorate the effects of cognitive impairment. Understanding the mechanisms underpinning these enrichment-mediated benefits are of great interest for designing effective interventions to boost cognitive function. MSK1 is thought to act as a transducer of MAPK signalling to gene expression within neurons, in response to extracellular signals upregulated by environmental enrichment, by phosphorylating the nuclear transcription factor CREB, and modifying chromatin structure through histone H3 phosphorylation. As such, MSK1 is positioned to play an important role in mediating neuronal changes within the hippocampus in response to environmental enrichment by regulating activity-dependent transcriptional changes. Here, mice homozygous for a kinase-inactivate form of MSK1 fail to phosphorylate CREB in response to BDNF-TrkB stimulation, and the kinase activity of MSK1 is demonstrated to regulate over half of the transcriptional changes induced following 3 months of environmental enrichment. Genes regulated by MSK1 included the IEGs Egr1 and Arc/Arg3.1, and appeared to be involved in restructuring the hippocampal extracellular environment, regulating primary cilium structure and MAPK signalling. Interestingly expression of MSK1 itself and MAPK pathway signalling appeared to be regulated in a homeostatic manner by environmental enrichment. Further experiments with a shorter 1 week period of enrichment indicated a potential role for the kinase activity of MSK1 in a transient environmental enrichment-induced decrease in AMPAR-mediated glutamatergic transmission and a potential effect in remodelling CA3/CA1 synaptic signalling, however both 1 week and 5 week periods of EE failed to show an MSK1 kinase activity-dependent effect on several aspects of CA1 neuron morphology, synaptic transmission, short-term presynaptic plasticity and synaptic transmission. Exposure to 1 week and 5 week periods of EE was also associated with xiv decreased postsynaptic expression of calcium-permeable AMPARs which could act as a potential form of EE-regulated metaplasticity at SC/CA1 synapses. Behavioural assays also revealed a novel role for MSK1 in regulating novelty-motivated behaviour, with kinase inactivation associated with reduced object investigation and impaired social memory, regardless of enrichment. This work implicates MSK1 as an important regulator of experience-dependent structural and synaptic changes within the hippocampus, further adding to the body of work characterising the kinase function of MSK1 already established by the Frenguelli lab

Will Renunciation of a Bequest or Failure to Claim a Statutory Share Constitute a Taxable Gift

In 1948 the 80th Congress amended the Internal Revenue Code in an effort to eliminate the discrimination theretofore enjoyed by residents of states which had adopted the community property system.\u27 Substantial equalization in the estate and gift tax fields is expected to follow from the marital deduction and gift tax splitting privileges. Moreover, these changes have focused attention upon a problem which caused considerable concern to conservative tax advisors even before the 1948 Tax Amendment. It has long been a doubtful question whether the renunciation of testamentary benefits would be held to constitute a taxable gift. The Act and the proposed regulations make it reasonably clear that a widow will not incur a gift tax as a result of renouncing a bequest or failing to claim her statutory share. But what of a child who (1) renounces a legacy, or (2) fails to claim a statutory share where such right exists because of his parent\u27s failure to mention him in the will? Will he be deemed to have made a taxable gift? The purpose of this note is to analyze the probable basis of gift tax liability in these two latter situations

Extended Photometry for the DEEP2 Galaxy Redshift Survey: A Testbed for Photometric Redshift Experiments

This paper describes a new catalog that supplements the existing DEEP2 Galaxy Redshift Survey photometric and spectroscopic catalogs with ugriz photometry from two other surveys; the Canada-France-Hawaii Legacy Survey (CFHTLS) and the Sloan Digital Sky Survey (SDSS). Each catalog is cross-matched by position on the sky in order to assign ugriz photometry to objects in the DEEP2 catalogs. We have recalibrated the CFHTLS photometry where it overlaps DEEP2 in order to provide a more uniform dataset. We have also used this improved photometry to predict DEEP2 BRI photometry in regions where only poorer measurements were available previously. In addition, we have included improved astrometry tied to SDSS rather than USNO-A2.0 for all DEEP2 objects. In total this catalog contains ~27,000 objects with full ugriz photometry as well as robust spectroscopic redshift measurements, 64% of which have r > 23. By combining the secure and accurate redshifts of the DEEP2 Galaxy Redshift Survey with ugriz photometry, we have created a catalog that can be used as an excellent testbed for future photo-z studies, including tests of algorithms for surveys such as LSST and DES.Comment: 12 pages, 6 figures and 5 tables. Accepted to The Astrophysical Journal Supplement. Catalogs are publicly available at http://deep.ps.uci.edu/DR4/photo.extended.htm

Prey Selection by Freshwater Predators with Different Foraging Strategies

We observed several freshwater predators, including the odonate larvae Pachydiplax longipennis and Anax junius, the hemipterans Notonecta unifasciata and Buenoa scimitra, the dytiscid larva Acilius semisulcatus, and juvenile Gambusia affinis, feeding on a variety of microcrustacean prey and determined the frequency of the component parts of predator–prey interactions (encounter, attack, capture, ingestion). Encounter rates were the most important determinant of predator selectivity when predators were presented with a variety of microcrustacean prey. When only copepod species were used as prey, however, both encounter rates and capture success were important in determining predator diets. We used our data to test hypotheses concerning relationships between predator foraging mode and patterns of prey selection: mobile predators exhibited stronger selection for sedentary prey than did sit-and-wait predators; our own and literature data also indicated that macroinvertebrate sit-and-wait predators are better able to capture, and have higher selectivity for evasive prey than do mobile predators. A predator's attack acceleration, however, may be a better predictor of its selectivity for evasive versus nonevasive prey than its mean swimming speed

Large-effect flowering time mutations reveal conditionally adaptive paths through fitness landscapes in Arabidopsis thaliana.

Contrary to previous assumptions that most mutations are deleterious, there is increasing evidence for persistence of large-effect mutations in natural populations. A possible explanation for these observations is that mutant phenotypes and fitness may depend upon the specific environmental conditions to which a mutant is exposed. Here, we tested this hypothesis by growing large-effect flowering time mutants of Arabidopsis thaliana in multiple field sites and seasons to quantify their fitness effects in realistic natural conditions. By constructing environment-specific fitness landscapes based on flowering time and branching architecture, we observed that a subset of mutations increased fitness, but only in specific environments. These mutations increased fitness via different paths: through shifting flowering time, branching, or both. Branching was under stronger selection, but flowering time was more genetically variable, pointing to the importance of indirect selection on mutations through their pleiotropic effects on multiple phenotypes. Finally, mutations in hub genes with greater connectedness in their regulatory networks had greater effects on both phenotypes and fitness. Together, these findings indicate that large-effect mutations may persist in populations because they influence traits that are adaptive only under specific environmental conditions. Understanding their evolutionary dynamics therefore requires measuring their effects in multiple natural environments

Assessing and Improving the Ecological Function of Linear Parks Along the Lower Los Angeles River Channel, Los Angeles County, California, US

Long overlooked by conservation groups and ecologists, urban open spaces are now seen as important contributors to biodiversity at various scales. Urban greenspaces often represent the only “nature” millions of human residents around the world ever interact with, and provide cooling and aesthetic relief from the urban hardscape. In the Los Angeles Metropolitan area, over the past three decades, non-profit advocacy groups and institutions have established a network of bike paths, neighborhood access points, habitat restoration, and recreational amenities along the Los Angeles River, a major urban waterway. We investigated the environmental contribution provided by numerous linear landscaped parks along the river, focusing on climate amelioration (i.e., cooling within heat islands) in the parks and surrounding neighborhoods, and on their contribution to local biodiversity, utilizing an indicator species approach. We conducted plant surveys of the parks, documenting locally native, non-local California native, and non-native species, and examined the occurrence of 15 riparian indicator species of wildlife in the parks and in 500-meter buffer zones surrounding each park utilizing citizen science data. We then explore correlations between indicator species richness and environmental variables. We note important occurrences of relict riparian vegetation in several linear parks, as well as both planted and naturally-occurring special-status plant and wildlife species. Finally, we discuss challenges to managing natural habitat in highly-urban parks, many of which support important relict vegetation and/or special-status species, and offer suggestions on how they may be improved

Non-Equilibrium Large N Yukawa Dynamics: marching through the Landau pole

The non-equilibrium dynamics of a Yukawa theory with N fermions coupled to a scalar field is studied in the large N limit with the goal of comparing the dynamics predicted from the renormalization group improved effective potential to that obtained including the fermionic backreaction. The effective potential is of the Coleman-Weinberg type. Its renormalization group improvement is unbounded from below and features a Landau pole. When viewed self-consistently, the initial time singularity does not arise. The different regimes of the dynamics of the fully renormalized theory are studied both analytically and numerically. Despite the existence of a Landau pole in the model, the dynamics of the mean field is smooth as it passes the location of the pole. This is a consequence of a remarkable cancellation between the effective potential and the dynamical chiral condensate. The asymptotic evolution is effectively described by a quartic upright effective potential. In all regimes, profuse particle production results in the formation of a dense fermionic plasma with occupation numbers nearly saturated up to a scale of the order of the mean field. This can be interpreted as a chemical potential. We discuss the implications of these results for cosmological preheating.Comment: 36 pages, 14 figures, LaTeX, submitted to Physical Review

Impact of Immersive Training on Senior Chemical Engineering Students\u27 Prioritization of Process Safety Decision Criteria

Every year new safety features and regulations are employed within the process industry to reduce risks associated with operations. Despite these advancements chemical plants remain hazardous places, and the role of the engineer will always involve risk mitigation through real time decision making. Results from a previous study by Kongsvik et al., 2015 indicated that there were three types of decisions in major chemical plants: strategic decisions, operational decisions, and instantaneous decisions. The study showed the importance for improving upon engineers’ operational and instantaneous choices when tasked with quick solutions in the workforce. In this research study, we dive deeper to understand how senior chemical engineering students’ prioritize components of decision making such as budget, productivity, relationships, safety, and time, and how this prioritization may change as a result of participation in a digital immersive training environment called Contents Under Pressure. More specifically, we seek to address the following two research questions: (1) How do senior chemical engineering students prioritize safety in comparison to criteria such as budget, personal relationships, plant productivity, and time in a process safety context, and (2) How does senior chemical engineering students’ prioritization of decision making criteria (budget, personal relationships, plant productivity, safety, and time) change after exposure to a virtual process safety decision making environment? As part of this study, 187 senior chemical engineering students from three separate institutions completed a pre- and post-reflection survey around their engagement with Contents Under Pressure and asked them to rank their prioritizations of budget, productivity, relationships, safety, and time. Data was analyzed using descriptive statistics, and Friedman and Wilcoxon-sign-rank post hoc analyses were completed to determine any statistical differences between the rankings of decision making factors before and after engagement with Contents Under Pressure. Simulating process safety decision making with interactive educational supports may increase students’ understanding of genuine workplace environments and factors that contribute to process safety, without the real world hazards that result from poor decision making. By understanding how students prioritize these factors, chemical engineering curricula can be adapted to focus on the areas of process safety decision making where students need the largest improvement, thereby better preparing them to enter the engineering workforce

The influence of sensory experience on the glutamatergic synapse

The ability of glutamatergic synaptic strength to change in response to prevailing neuronal activity is believed to underlie the capacity of animals, including humans, to learn from experience. This learning better equips animals to safely navigate challenging and potentially harmful environments, while reinforcing behaviours that are conducive to survival. Early descriptions of the influence of experience on behaviour were provided by Donald Hebb who showed that an enriched environment improved performance of rats in a variety of behavioural tasks, challenging the widely-held view at the time that psychological development and intelligence were largely predetermined through genetic inheritance. Subsequent studies in a variety of species provided detailed cellular and molecular insights into the neurobiological adaptations associated with enrichment and its counterparts, isolation and deprivation. Here we review those experience-dependent changes that occur at the glutamatergic synapse, and which likely underlie the enhanced cognition associated with enrichment. We focus on the importance of signalling initiated by the release of BDNF, and a prime downstream effector, MSK1, in orchestrating the many structural and functional neuronal adaptations associated with enrichment. In particular we discuss the MSK1-dependent expansion of the dynamic range of the glutamatergic synapse, which may allow enhanced information storage or processing, and the establishment of a genomic homeostasis that may both stabilise the enriched brain, and may make it better able to respond to novel experiences