Post Pandemic Praxis: A Meditation on Psalm 23

As universities and colleges begin to define ways to move forward in a post-COVID year, Psalm 23 offers some thoughtful practices for how to return to a new normal while still dealing with the side effects of pandemic pivoting. This article considers what provisions the Lord offers through the paradigm of Psalm 23. This Psalm offers helpful perspective, context, an overarching vision of life, and specific steps that are vital in recovering from valley experiences as people move towards a restored and flourishing new normal

Variable-focus microscopy and UV surface dissolution imaging as complementary techniques in intrinsic dissolution rate determination

This work reports a novel approach to the assessment of the surface properties of compacts used in Surface Dissolution Imaging (SDI). SDI is useful for determining intrinsic dissolution rate (IDR), an important parameter in early stage drug development. Surface topography, post-compaction and post-SDI run, have been measured using a non-contact, optical, three-dimensional microscope based on focus variation, the Alicona Infinite Focus Microscope, with the aim of correlating the IDRs to the surface properties. Ibuprofen (IBU) was used as a model poorly-soluble drug. DSC and XRD were used to monitor possible polymorphic changes that may have occurred post-compaction and post-SDI run. IBUs IDR decreased from 0.033 mg/min/cm2 to 0.022 mg/min/cm2 from 10 to 20 min, respectively, during the experiment. XRD and DSC showed no form changes during the SDI run. The surface topography images showed that a distinct imprint was embossed on the surfaces of some compacts which could affect IDRs. Surface parameter values were associated with the SDI experiments which showed strong correlations with the IDR values. The variable-focus microscope can be used as a complimentary tool in the determination of IDR values from the SDI

Site-selective spectroscopy and level ordering in C-phycocyanin

We present a combined fluorescence and hole-burning study of the biliprotein C-phycocyanin. Sharp zero-phonon holes compare with a broad structureless fluorescence. This finding is rationalized in terms of the special level structure in this pigment, the fast energy-transfer processes and a lack of correlation of the energies of the emissive states

A convenient design of growth tube

A convenient design of growth tub

Sand and gravel deposits of the coast and inner shelf East Coast, Northland Peninsula, New Zealand

The east coast of Northland has a narrow and steep inner shelf which reaches depths of 50m within 1.5 km offshore. Mixed sand and gravel sediments occur at 30-50m depths as thin (1-10m), discontinuous, sheet deposits underlain by planed, bedrock surfaces. The deposits lie off rocky sections of the coast which form high standing cliffs between drowned embayments. Coastal deposits are predominantly situated in the embayments as localised pockets totalling only 15% of the shoreline length. The hinterland consists of a dissected block of greywackes which are deeply weathered to clay except for unweathered coastal cliff exposures. During the Pleistocene, the coast and inner shelf have evolved under conditions of relative tectonic stability in comparison to much larger sea level fluctuations. Coastal sand and gravel sediments were derived predominantly from erosion of coastal rock, rather than from hinterland fluvial sources. In addition, a high regional shell sand content of 40% varies from 2-82% between beaches depending upon contributions of sediment from other sources. Beach morpho-dynamics display a quasi-seasonal pattern with a tendency to erosion in winter, accretion in spring-early summer, and a variable response in summer-autumn, although episodes of erosion are possible at any time of the year. Short term beach changes of 20-40m in two years were greater than <10m historical changes determined from air photos for the last 30-40 years. A comparison of inner shelf sediment samples within and between five areas along the coast did not show either marked textural or geographic groupings. The gravel deposits were not interpreted as relict fluvial as has been previously proposed, and are now thought to have been derived directly from the erosion of adjacent coastal exposure s during sea level highs 20-40m below present in the last glaciations and since the post-glacial transgression. Shell presently forms 36-56% of the inner shelf gravel fraction and is derived from contemporary inner shelf communities. The shell is mixed within the deposits to a depth of at least 1.5m, and to the base of one of the deposits. Other sediment and core data suggest that the deposits are now at least palimpsest and may be modern. Detailed studies of sediment mobility in the shallowest (20m deep) deposit indicate that sediment up to 50mm diameter is actively involved in a seabed transport system within the deposit, and that the deposits are presently evolving in terms of their sediment characteristics and spatial distribution of facies. The major implication of these findings for a proposal to dredge inner shelf deposits is that coastal erosion is not likely at the five deposits located off cliffed, rocky coasts. This conclusion is less certain for the shallowest deposit which is adjacent to a long, sand beach, but it is thought that dredging would have very little adverse physical effect

Probabilistic impact assessment of EV charging on residential UK LV networks

(paper accepted) The electricity demand from high penetrations of electric vehicles (EVs) in the UK may result in significant asset capacity issues (transformers and cables) and/or voltage drops in residential low voltage (LV) networks. This paper presents a probabilistic impact assessment of realistic EV charging on nine UK LV networks that are part of the ‘My Electric Avenue’ project. A deterministic impact assessment is initially compared against the stochastic to highlight the benefits of the latter. Monte Carlo simulations (considering 1-min resolution data) are undertaken to cater for domestic and EV load profile uncertainties. Results show that simplified (deterministic) analyses cannot truly quantify the impacts of EVs in LV networks. More importantly, the probabilistic assessment highlights that technical problems in these LV networks may occur for EV penetrations larger than 30%, and that 20 and 50% of the feeders and transformers, respectively, may exceed their capacity limits for high penetrations. Guidelines to adapt the probabilistic approach to help a network planner are finally discussed

Exploring novel North Water Polynya ecosystems under climate change

Climate change is rapidly reshaping species distributions in the Arctic, which could profoundly impact ecosystem structure and function. While considerable effort has focused on projecting future species distributions, assessing the impacts of range-shifting species on recipient communities and subsequent disruptions to food webs remains largely unstudied. Here, we address this gap by combining species distribution models and ecosystem models to explore the emergence of novel ecosystems in the North Water Polynya. The North Water Polynya is an open-water area between Greenland and Canada, surrounded by sea ice and one of the world’s most productive ocean ecosystems. Using existing literature and projections from species distribution models of four marine species, we develop six plausible future ecosystem scenarios for the North Water Polynya. These scenarios include changing biomass of primary producers, changing biomass and size structure of copepods, shifting abundances of forage fish species, and the establishment of killer whales. We find that the biomass of higher trophic levels show pronounced decreases in response to the decrease in pelagic primary producers, with polar bear biomass halving compared to present conditions. Changes in the copepod size structure has the largest impact on the entire ecosystem compared to the other novel ecosystem scenarios, suggesting a strong reliance of higher trophic levels on large, lipid-rich copepods. We further show that increasing capelin with a simultaneous decrease in Arctic cod biomass causes large decreases in the biomass of marine mammals such as polar bear, beluga and ringed seal. Finally, we show the establishment of killer whales as a key novel predator could have cascading top-down effects on the North Water Polynya ecosystem. The framework presented here provides an approach for exploring the emergence of novel ecosystems and highlights how climate change could disrupt a high Arctic ecosystem

Coping with strangers: how familiarity and active interactions shape group coordination in Corydoras aeneus.

Social groups composed of familiar individuals exhibit better coordination than unfamiliar groups; however, the ways familiarity contributes to coordination are poorly understood. Prior social experience probably allows individuals to learn the tendencies of familiar group-mates and respond accordingly. Without prior experience, individuals would benefit from strategies for enhancing coordination with unfamiliar others. We used a social catfish, Corydoras aeneus, that uses discrete, observable tactile interactions to assess whether active interactions could facilitate coordination, and how their role might be mediated by familiarity. We describe this previously understudied physical interaction, 'nudges', and show it to be associated with group coordination and cohesion. Furthermore, we investigated nudging and coordination in familiar/unfamiliar pairs. In all pairs, we found that nudging rates were higher during coordinated movements than when fish were together but not coordinating. We observed no familiarity-based difference in coordination or cohesion. Instead, unfamiliar pairs exhibited significantly higher nudging rates, suggesting that unfamiliar pairs may be able to compensate for unfamiliarity through increased nudging. By contrast, familiar individuals coordinated with comparatively little nudging. Second, we analysed nudging and cohesion within triplets of two familiar and one unfamiliar individual (where familiar individuals had a choice of partner). Although all individuals nudged at similar rates, the unfamiliar group-mate was less cohesive than its familiar group-mates and spent more time alone. Unfamiliar individuals that nudged their group-mates more frequently exhibited higher cohesion, indicating that nudging may facilitate cohesion for the unfamiliar group-mate. Overall, our results suggest that nudges can mitigate unfamiliarity, but that their usage is reduced in the case of familiar individuals, implying a cost is associated with the behaviour

Actinic Skin Damage and Mortality - the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study

BACKGROUND: Exposure to sunlight may decrease the risk of several diseases through the synthesis of vitamin D, whereas solar radiation is the main cause of some skin and eye diseases. However, to the best of our knowledge, the association of sun-induced skin damage with mortality remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: Subjects were 8472 white participants aged 25-74 years in the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. Cardiovascular disease mortality, cancer mortality, and all-cause mortality were obtained by either a death certificate or a proxy interview, or both. Actinic skin damage was examined and recorded by the presence and severity (absent, minimal, moderate, or severe) of overall actinic skin damage and its components (i.e., fine telangiectasia, solar elastosis, and actinic keratoses). Cox regression and Kaplan-Meier methods were applied to explore the associations. A total of 672 cancer deaths, 1500 cardiovascular disease deaths, and 2969 deaths from all causes were documented through the follow-up between 1971 and 1992. After controlling for potential confounding variables, severe overall actinic skin damage was associated with a 45% higher risk for all-cause mortality (95% CI: 1.22, 1.72; P<0.001), moderate overall skin damage with a 20% higher risk (95% CI: 1.08., 1.32; P<0.001), and minimal overall skin damage with no significant mortality difference, when compared to those with no skin damage. Similar results were obtained for all-cause mortality with fine telangiectasia, solar elastosis, and actinic keratoses. The results were similar for cancer and cardiovascular disease mortality. CONCLUSIONS: The present study gives an indication of an association of actinic skin damage with cardiovascular disease, cancer and all-cause mortality in white subjects. Given the lack of support in the scientific literature and potential unmeasured confounding factors, this finding should be interpreted with caution. More independent studies are needed before any practical recommendations can be made

Spectral hole burning: examples from photosynthesis

The optical spectra of photosynthetic pigment–protein complexes usually show broad absorption bands, often consisting of a number of overlapping, ‘hidden’ bands belonging to different species. Spectral hole burning is an ideal technique to unravel the optical and dynamic properties of such hidden species. Here, the principles of spectral hole burning (HB) and the experimental set-up used in its continuous wave (CW) and time-resolved versions are described. Examples from photosynthesis studied with hole burning, obtained in our laboratory, are then presented. These examples have been classified into three groups according to the parameters that were measured: (1) hole widths as a function of temperature, (2) hole widths as a function of delay time and (3) hole depths as a function of wavelength. Two examples from light-harvesting (LH) 2 complexes of purple bacteria are given within the first group: (a) the determination of energy-transfer times from the chromophores in the B800 ring to the B850 ring, and (b) optical dephasing in the B850 absorption band. One example from photosystem II (PSII) sub-core complexes of higher plants is given within the second group: it shows that the size of the complex determines the amount of spectral diffusion measured. Within the third group, two examples from (green) plants and purple bacteria have been chosen for: (a) the identification of ‘traps’ for energy transfer in PSII sub-core complexes of green plants, and (b) the uncovering of the lowest k = 0 exciton-state distribution within the B850 band of LH2 complexes of purple bacteria. The results prove the potential of spectral hole burning measurements for getting quantitative insight into dynamic processes in photosynthetic systems at low temperature, in particular, when individual bands are hidden within broad absorption bands. Because of its high-resolution wavelength selectivity, HB is a technique that is complementary to ultrafast pump–probe methods. In this review, we have provided an extensive bibliography for the benefit of scientists who plan to make use of this valuable technique in their future research