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Many retired people engage in volunteer opportunities as a means to give back to their communities, stay physically and intellectually active, and build and expand their social networks. However, our semi-structured interviews of six retirees found that they typically avoid searching for volunteer opportunities through websites and social media due to a lack of trust in those tools and a concern for privacy. Instead, they rely on word-of-mouth communication facilitated through emails with individuals and organizations they trust. To support this type of communication, we designed an adaptive interaction mechanism in the form of a newsletter with volunteer opportunities that are personalized using recommender system technology. The newsletter mechanism leverages personal connections through user-defined preference-based communities that allow users to share volunteer opportunities with their peers. 

Generative models for 3D shapes represented by hierar- chies of parts can generate realistic and diverse sets of out- puts. However, existing models suffer from the key practi- cal limitation of modelling shapes holistically and thus can- not perform conditional sampling, i.e. they are not able to generate variants on individual parts of generated shapes without modifying the rest of the shape. This is limiting for applications such as 3D CAD design that involve adjust- ing created shapes at multiple levels of detail. To address this, we introduce LSD-StructureNet, an augmentation to the StructureNet architecture that enables re-generation of parts situated at arbitrary positions in the hierarchies of its outputs. We achieve this by learning individual, probabilis- tic conditional decoders for each hierarchy depth. We eval- uate LSD-StructureNet on the PartNet dataset, the largest dataset of 3D shapes represented by hierarchies of parts. Our results show that contrarily to existing methods, LSD- StructureNet can perform conditional sampling without im- pacting inference speed or the realism and diversity of its outputs. 

Abstract Glucocorticoids are regularly used as biomarkers of relative health for individuals and populations. Around the Western Antarctic Peninsula (WAP), baleen whales have and continue to experience threats, including commercial harvest, prey limitations and habitat change driven by rapid warming, and increased human presence via ecotourism. Here, we measured demographic variation and differences across the foraging season in blubber cortisol levels of humpback whales (Megaptera novaeangliae) over two years around the WAP. Cortisol concentrations were determined from 305 biopsy samples of unique individuals. We found no significant difference in the cortisol concentration between male and female whales. However, we observed significant differences across demographic groups of females and a significant decrease in the population across the feeding season. We also assessed whether COVID-19-related reductions in tourism in 2021 along the WAP correlated with lower cortisol levels across the population. The decline in vessel presence in 2021 was associated with a significant decrease in humpback whale blubber cortisol concentrations at the population level. Our findings provide critical contextual data on how these hormones vary naturally in a population over time, show direct associations between cortisol levels and human presence, and will enable comparisons among species experiencing different levels of human disturbance. 

Abstract Low-surface-brightness galaxies (LSBGs) are excellent probes of quenching and other environmental processes near massive galaxies. We study an extensive sample of LSBGs near massive hosts in the local universe that are distributed across a diverse range of environments. The LSBGs with surface-brightness ${\mu }_{\mathrm{eff},\mathit{g}}>24.2\mathrm{mag}{\mathrm{arcsec}}^{-2}$are drawn from the Dark Energy Survey Year 3 catalog while the hosts with masses $9.0<\log \left({\mathcal{M}}_{\star }/M_{\odot }\right)<11.0$comparable to the Milky Way and the Large Magellanic Cloud are selected from the z0MGS sample. We study the projected radial density profiles of LSBGs as a function of their color and surface brightness around hosts in both the rich Fornax–Eridanus cluster environment and the low-density field. We detect an overdensity with respect to the background density, out to 2.5 times the virial radius for both hosts in the cluster environment and the isolated field galaxies. When the LSBG sample is split byg−icolor or surface brightnessμ_eff,g, we find the LSBGs closer to their hosts are significantly redder and brighter, like their high-surface-brightness counterparts. The LSBGs form a clear “red sequence” in both the cluster and isolated environments that is visible beyond the virial radius of the hosts. This suggests preprocessing of infalling LSBGs and a quenched backsplash population around both host samples. More so, the relative prominence of the “blue cloud” feature implies that preprocessing is ongoing near the isolated hosts compared to the cluster environment where the LSBGs are already well processed. 

Let $$G$$ be one of the two multigraphs obtained from $$K_4-e$$ by replacing two edges with a double-edge while maintaining a minimum degree of~2. We find necessary and sufficient conditions on $$n$$ and $$\lambda$$ for the existence of a $$G$$-decomposition of $$^{\lambda}K_n$$. 

Consider the multigraph obtained by adding a double edge to $$K_4-e$$. Now, let $$D$$ be a directed graph obtained by orientating the edges of that multigraph. We establish necessary and sufficient conditions on $$n$$ for the existence of a $$(K^{*}_{n},D)$$-design for four such orientations.