More Like this

1. The fascinating story of axial ligand dependent spectroscopy and redox-properties in iron( ii ) phthalocyanines

   https://doi.org/10.1039/d3dt02565a  

   Ziegler, Christopher J; Nemykin, Victor N (November 2023, Dalton Transactions)

   Iron phthalocyanines play crucial fundamental and applied roles ranging from bulk colorants to components of advanced materials. In this mini-review, we discuss the influence of axial ligand identity on spectroscopic and redox properties of iron(ii) phthalocyanines. 

   more » « less
2. The s Process and Beyond

   https://doi.org/10.1146/annurev-nucl-102422-080857  

   Lugaro, Maria; Pignatari, Marco; Reifarth, René; Wiescher, Michael (September 2023, Annual Review of Nuclear and Particle Science)

   Neutron captures produce the vast majority of abundances of elements heavier than iron in the Universe. Beyond the classical slow ( s) and rapid ( r) processes, there is observational evidence for neutron-capture processes that operate at neutron densities in between, at different distances from the valley of β stability. Here, we review the main properties of the s process within the general context of neutron-capture processes and the nuclear physics input required to investigate it. We describe massive stars and asymptotic giant branch stars as the s-process astrophysical sites and discuss the related physical uncertainties. We also present current observational evidence for the s process and beyond, which ranges from stellar spectroscopic observations to laboratory analysis of meteorites. 

   more » « less
3. Dispersion of deep-sea hydrothermal plumes at the Endeavour Segment of the Juan de Fuca Ridge: a multiscale numerical study

   https://doi.org/10.3389/fmars.2023.1213470  

   Xu, Guangyu; German, Christopher R (July 2023, Frontiers in Marine Science)

   A multiscale numerical framework has been developed to investigate the dispersion of deep-sea hydrothermal plumes that originate from the Endeavour Segment of the Juan de Fuca Ridge located in the Northeast Pacific. The analysis of simulation outputs presented in this study provides insights into the influences of tidal forcing and the buoyancy flux associated with hydrothermal venting on ocean circulation and plume dispersion in the presence of pronounced seafloor topography. The results indicate that tidal forcing drives anti-cyclonic circulation near the ridge-axis, while hydrothermal venting induces cyclonic circulation around vent fields within the axial rift valley. Tidal forcing has a notable impact on plume dispersion, particularly near the large topographic features to the north of the Endeavour Segment. Furthermore, plume dispersion exhibits notable inter-annual variability, with a northbound trajectory in 2016 and a southbound trajectory in 2021. The study also reveals that both buoyancy fluxes and tidal forcing enhance the mixing of hydrothermal plumes with ambient seawater. 

   more » « less
4. Mapping the Iron Age in Southern Africa: Magnetometry at two Iron Age villages in Western Zambia

   https://doi.org/10.1016/j.jas.2024.105937  

   McKeeby, Zachary (March 2024, Journal of Archaeological Science)

   In recent years the use of near-surface geophysical survey – especially magnetometry – has been on the rise across sub-Saharan Africa, illustrating its utility at both large and/or built-up sites with stone architecture, as well as smaller and more ephemeral village sites in equatorial and sub-tropical regions of the continent. This article describes geophysical surveys and excavations at Nanga and Kanono, two Iron Age village sites in the Machile Valley, Western Zambia, undertaken between 2019 and 2022. Surveys allowed for detailed analyses of village layouts and showed the relationship between domestic areas and areas of iron production. Subsequent ground-truthing of both domestic and iron production areas elucidated differential spatial patterns of iron production stages (i.e., smelting and smithing) between village sites dating to between 800 and 1400, and allowed for the identification, excavation, and analyses of several Early Iron Age smelting furnaces. 

   more » « less
5. Generalization of the two-point-source resolution criterion in the presence of noise

   https://doi.org/10.1364/OL.494910  

   Wani, Pranav; Usmani, Kashif; Javidi, Bahram (January 2023, Optics Letters)

   The two-point-source resolution criterion is widely used to quantify the performance of imaging systems. The two main approaches for the computation of the two-point-source resolution are the detection theoretic and visual analyses. The first assumes a shift-invariant system and lacks the ability to incorporate two different point spread functions (PSFs), which may be required in certain situations like computing axial resolution. The latter approach, which includes the Rayleigh criterion, relies on the peak-to-valley ratio and does not properly account for the presence of noise. We present a heuristic generalization of the visual two-point-source resolution criterion using Gaussian processes (GP). This heuristic criterion is applicable to both shift-invariant and shift-variant imaging modalities. This criterion can also incorporate different definitions of resolution expressed in terms of varying peak-to-valley ratios. Our approach implicitly incorporates information about noise statistics such as the variance or signal-to-noise ratio by making assumptions about the spatial correlation of PSFs in the form of kernel functions. Also, it does not rely on an analytic form of the PSF. 

   more » « less