Comment on "Measurement of quantum states of neutrons in the Earth's gravitational field"

In the paper by V.V. Nesvizhevsky et al., Phys. Rev. D 67, 102002 (2003), it is argued that the lowest quantum state of neutrons in the Earth's gravitational field has been experimentally identified. While this is most likely correct, it is imperative to investigate all alternative explanations of the result in order to close all loopholes, as it is the first experiment ever claimed to have observed gravitational quantum states. Here we show that geometrical effects in the experimental setup can mimic the results attributed to gravity. Modifications of the experimental setup to close these possible loopholes are suggested.Comment: 4 pages, to appear in Phys.Rev.

A Passively Mode-locked Nanosecond Laser with an Ultra-narrow Spectral Width

Many different mode-locking techniques have been realized in the past [1, 2], but mainly focused on increasing the spectral bandwidth to achieve ultra-short coherent light pulses with well below picosecond duration. In contrast, no mode-locked laser scheme has managed to generate Fourier-limited nanosecond long pulses, which feature narrow spectral bandwidths (~MHz regime) instrumental to applications in spectroscopy, efficient excitation of molecules, sensing, and quantum optics. The related limitations are mainly caused by the adverse operation timescales of saturable absorbers, as well as by the low strength of the nonlinear effects typically reachable through nanosecond pulses with manageable energies

β-Adrenoceptor activation depresses brain inflammation and is neuroprotective in lipopolysaccharide-induced sensitization to oxygen-glucose deprivation in organotypic hippocampal slices

<p>Abstract</p> <p>Background</p> <p>Inflammation acting in synergy with brain ischemia aggravates perinatal ischemic brain damage. The sensitizing effect of pro-inflammatory exposure prior to hypoxia is dependent on signaling by TNF-α through TNF receptor (TNFR) 1. Adrenoceptor (AR) activation is known to modulate the immune response and synaptic transmission. The possible protective effect of <inline-formula><m:math xmlns:m="http://www.w3.org/1998/Math/MathML" name="1742-2094-7-94-i1"><m:mover accent="true"><m:mi>α</m:mi><m:mo>˜</m:mo></m:mover></m:math></inline-formula> and <inline-formula><m:math xmlns:m="http://www.w3.org/1998/Math/MathML" name="1742-2094-7-94-i2"><m:mover accent="true"><m:mi>β</m:mi><m:mo>˜</m:mo></m:mover></m:math></inline-formula>AR activation against neuronal damage caused by tissue ischemia and inflammation, acting in concert, was evaluated in murine hippocampal organotypic slices treated with lipopolysaccharide (LPS) and subsequently subjected to oxygen-glucose deprivation (OGD).</p> <p>Method</p> <p>Hippocampal slices from mice were obtained at P6, and were grown <it>in vitro </it>for 9 days on nitrocellulose membranes. Slices were treated with β1(dobutamine)-, β2(terbutaline)-, α1(phenylephrine)- and α2(clonidine)-AR agonists (5 and 50 μM, respectively) during LPS (1 μg/mL, 24 h) -exposure followed by exposure to OGD (15 min) in a hypoxic chamber. Cell death in the slice CA1 region was assessed by propidium iodide staining of dead cells.</p> <p>Results</p> <p>Exposure to LPS + OGD caused extensive cell death from 4 up to 48 h after reoxygenation. Co-incubation with β1-agonist (50 μM) during LPS exposure before OGD conferred complete protection from cell death (P < 0.001) whereas the β2-agonist (50 μM) was partially protective (p < 0.01). Phenylephrine was weakly protective while no protection was attained by clonidine. Exposure to both β1- and β2-agonist during LPS exposure decreased the levels of secreted TNF-α, IL-6 and monocyte chemoattractant protein-1 and prevented microglia activation in the slices. Dobutamine remained neuroprotective in slices exposed to pure OGD as well as in TNFR1^-/-and TNFR2^-/-slices exposed to LPS followed by OGD.</p> <p>Conclusions</p> <p>Our data demonstrate that activation of both β1- and β2-receptors is neuroprotective and may offer mechanistic insights valuable for development of neuro-protective strategies in neonates.</p

Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?

<p>Abstract</p> <p>Background</p> <p>Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. <it>Birgus latro </it>Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. <it>B. latro </it>has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as <it>B. latro </it>have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of <it>B. latro</it>, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide.</p> <p>Results</p> <p>The primary and secondary olfactory centers dominate the brain of <it>B. latro </it>and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two suggest <it>that B. latro </it>has visual and mechanosensory skills that are comparable to those of marine Crustacea.</p> <p>Conclusions</p> <p>In parallel to previous behavioral findings that <it>B. latro </it>has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab <it>Coenobita clypeatus </it>suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in <it>B. latro </it>brains surpasses that in other terrestrial arthropods, as e.g. the honeybee <it>Apis mellifera </it>or the moth <it>Manduca sexta</it>, by two orders of magnitude suggesting that <it>B. latro </it>in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.</p

Hemoglobin induces inflammation after preterm intraventricular hemorrhage by methemoglobin formation.

Cerebral intraventricular hemorrhage (IVH) is a major cause of severe neurodevelopmental impairment in preterm infants. To date, no therapy is available that prevents infants from developing serious neurological disability following IVH. Thus, to develop treatment strategies for IVH, it is essential to characterize the initial sequence of molecular events that leads to brain damage. In this study, we investigated extracellular hemoglobin (Hb) as a causal initiator of inflammation in preterm IVH

Governance for sustainable urban development: the double function of SDG indicators

At the core of the 2030 Agenda for Sustainable Development is the imperative of monitoring progress and holding policy-makers accountable. For this purpose, 17 Sustainable Development Goals (SDGs) and 230 global indicators were established with the double function of being a report card and a management tool. In the light of a pilot study about the experiences of local planning officials in the City of Gothenburg, Sweden, in relation to the suggested indicators for SDG 11, ‘Make cities and human settlements inclusive, safe, resilient and sustainable’, and a comparison with findings in four other cities, the paper argues for a need to reprioritize indicator criteria to serve better governance for sustainable development in diverse urban contexts worldwide