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Dispersal in microbes: fungi in indoor air are dominated by outdoor air and show dispersal limitation at short distances.
The indoor microbiome is a complex system that is thought to depend on dispersal from the outdoor biome and the occupants' microbiome combined with selective pressures imposed by the occupants' behaviors and the building itself. We set out to determine the pattern of fungal diversity and composition in indoor air on a local scale and to identify processes behind that pattern. We surveyed airborne fungal assemblages within 1-month time periods at two seasons, with high replication, indoors and outdoors, within and across standardized residences at a university housing facility. Fungal assemblages indoors were diverse and strongly determined by dispersal from outdoors, and no fungal taxa were found as indicators of indoor air. There was a seasonal effect on the fungi found in both indoor and outdoor air, and quantitatively more fungal biomass was detected outdoors than indoors. A strong signal of isolation by distance existed in both outdoor and indoor airborne fungal assemblages, despite the small geographic scale in which this study was undertaken (<500 m). Moreover, room and occupant behavior had no detectable effect on the fungi found in indoor air. These results show that at the local level, outdoor air fungi dominate the patterning of indoor air. More broadly, they provide additional support for the growing evidence that dispersal limitation, even on small geographic scales, is a key process in structuring the often-observed distance-decay biogeographic pattern in microbial communities
Fermi surface, possible unconventional fermions, and unusually robust resistive critical fields in the chiral-structured superconductor AuBe
The noncentrosymmetric superconductor (NCS) AuBe is investigated using a
variety of thermodynamic and resistive probes in magnetic fields of up to 65~T
and temperatures down to 0.3~K. Despite the polycrystalline nature of the
samples, the observation of a complex series of de Haas-van Alphen (dHvA)
oscillations has allowed the calculated bandstructure for AuBe to be validated.
This permits a variety of BCS parameters describing the superconductivity to be
estimated, despite the complexity of the measured Fermi surface. In addition,
AuBe displays a nonstandard field dependence of the phase of dHvA oscillations
associated with a band thought to host unconventional fermions in this chiral
lattice. This result demonstrates the power of the dHvA effect to establish the
properties of a single band despite the presence of other electronic bands with
a larger density of states, even in polycrystalline samples. In common with
several other NCSs, we find that the resistive upper critical field exceeds
that measured by heat capacity and magnetization by a considerable factor. We
suggest that our data exclude mechanisms for such an effect associated with
disorder, implying that topologically protected superconducting surface states
may be involved
Pennsylvania Folklife Vol. 31, No. 3
• Jamison City • Domestic Architecture in Lancaster County • Conversation with Marguerite de Angeli • Who Put the Turnip on the Grave? • Pennsylfawnisch Deitsch un Pfalzer: Dialect Comparisons Old and New • John Philip Boehm: Pioneer Pennsylvania Pastor • The Search for our German Ancestors • Aldes un Neieshttps://digitalcommons.ursinus.edu/pafolklifemag/1095/thumbnail.jp
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