Louis Reichardt: The long climb to science's summits

From the highest mountains to biology's own Everest—the brain—Reichardt tackles the biggest challenges of climbing and biology

Shadows, Signals, and Stability in Einsteinian Cubic Gravity

We conduct a preliminary investigation into the phenomenological implications of Einsteinian cubic gravity (ECG), a 4-dimensional theory of gravity cubic in curvature of interest for its unique formulation and properties. We find an analytic approximation for a spherically symmetric black hole solution to this theory using a continued fraction ansatz. This approximate solution is valid everywhere outside of the horizon and we use it to study the orbit of massive test bodies near a black hole, specifically computing the innermost stable circular orbit. We compute constraints on the ECG coupling parameter imposed by Shapiro time delay. We then compute the shadow of an ECG black hole and find it to be larger than its Einsteinian counterpart in general relativity for the same value of the mass. Applying our results to Sgr A*, we find that departures from general relativity are small but in principle distinguishable

NT-3, like NGF, Is Required for Survival of Sympathetic Neurons, but Not Their Precursors

AbstractSuperior cervical ganglia of postnatal mice with a targeted disruption of the gene for neurotrophin-3 have 50% fewer neurons than those of wild-type mice. In culture, neurotrophin-3 increases the survival of proliferating sympathetic precursors. Both precursor death (W. ElShamy et al., 1996, Development 122, 491–500) and, more recently, neuronal death (S. Wyatt et al., 1997, EMBO J. 16, 3115–3123) have been described in mice lacking NT-3. Consistent with the second report, we found that, in vivo, neurogenesis and precursor survival were unaffected by the absence of neurotrophin-3 but neuronal survival was compromised so that only 50% of the normal number of neurons survived to birth. At the time of neuron loss, neurotrophin-3 expression, assayed with a lacZ reporter, was detected in sympathetic target tissues and blood vessels, including those along which sympathetic axons grow, suggesting it may act as a retrograde neurotrophic factor, similar to nerve growth factor. To explore this possibility, we compared neuron loss in neurotrophin-3-deficient mice with that in nerve growth factor-deficient mice and found that neuronal losses occurred at approximately the same time in both mutants, but were less severe in mice lacking neurotrophin-3. Eliminating one or both neurotrophin-3 alleles in mice that lack nerve growth factor does not further reduce sympathetic neuron number in the superior cervical ganglion at E17.5 but does alter axon outgrowth and decrease salivary gland innervation. Taken together these results suggest that neurotrophin-3 is required for survival of some sympathetic neurons that also require nerve growth factor

Dietary fibers inhibit obesity in mice, but host responses in the cecum and liver appear unrelated to fiber-specific changes in cecal bacterial taxonomic composition

Peer reviewedPublisher PD

Specific substrate-driven changes in human faecal microbiota composition contrast with functional redundancy in short-chain fatty acid production

The Rowett Institute and Biomathematics & Statistics Scotland receive financial support from the Scottish Government Rural and Environmental Sciences and Analytical Services. Nicole Reichardt was funded by a Scottish Government Strategic Partnership on Food and Drink Science. We would like to thank Donna Henderson for carrying out GC analysis and Alan Walker for help and advice with bioinformatic sequence analysis. Supplementary information is available at ISME Journal’s website.Peer reviewedPostprin

Managing inventories of reusable containers for food take-away at a restaurant

peer reviewedSingle-use packaging in the food services sector accounts for a substantial amount of waste, leading some restaurants to offer customers reusable containers for take-away or delivery orders. Once used, customers may return these containers to the same restaurant or another restaurant in the reusable container network or they may not return them at all. The restaurant hence faces both uncertain demand and returns for reusable containers and needs to decide on the number of containers to stock to serve its customers. We formulate this problem by modeling it as a continuous-time Markov Decision Process. Through a numerical study, we investigate the effect that different balances of demand and return intensities and their coupling have on the average total cost for the restaurant. We find that greater demand and return coupling reduces average costs, but the effects are most beneficial when the overall demand and returns of the restaurant are balanced. The restaurant can reduce costs by optimizing the supplier visit frequency in addition to the inventory level of clean containers after the supplier visit. The supplier's choice of the level of the visit cost is important as smaller scale restaurants may be penalized by a larger supplier visit cost, dissuading them from participating in reusable container systems

Total HDAC inhibitory effects of supernatants from gut bacterial strains.

<p>(A) Screening of cell free supernatants (CFS) from 79 bacterial strains for total HDAC inhibition on whole HT-29 cells. Trichostatin A (TSA) is a negative control. (B) CFS of three selected bacterial strains tested for HDAC inhibition on HT-29 whole cell and HT-29 cell lysates. Trichostatin A (TSA) is used as a negative control. Significances tested against YCFA ** (p<0.005) *** (P<0.001).</p