Magnetoencephalography (MEG) is a method to study electrical activity in the brain. MEG signals are modeled by primary currents, which represent neuronal activity, and associated passive volume currents, which depend on the conductivity distribution within the body. The effect of conductivity inhomogeneities can be described as if additional virtual source currents were present. Virtual sources help to understand conductivity effects independently from the sensor array properties. The Volume Current Formulation (VCF) of the virtual sources focuses on altered patterns of volume currents, whereas in the Secondary Current Formulation (SCF) the virtual sources are at locations where conductivity changes. We derived and compared these formulations for deviations from a reference conductivity distribution. In VCF, the virtual sources are located only where the conductivity deviation is non-zero, but their orientation and magnitude depend on the local electric field. In contrast, in SCF, both the location and the orientation of the virtual sources are determined by the conductivity distribution, typically by the anatomical tissue boundaries. In SCF, however, all conductivity boundaries, including those in the reference distribution, generally need to be considered. For spherically symmetric reference conductivity, in VCF the radial component of a virtual source does not contribute to any component of the magnetic field, whereas in SCF the radial component of a virtual source does not contribute to the radial component but contributes to the tangential components of the magnetic field. Complementary descriptions using VCF and SCF were illustrated in a model for fontanels in infants.
Packet analysis tools conventionally present capture data through tabular packet lists, constraining the analyst to a sequential view that obscures the relational structure of network communication. This paper presents Galaxy Tracer, a browser-native packet capture exploration system in which the default interface is an interactive three-dimensional network topology rather than a packet list. Hosts appear as spatially positioned nodes, conversations as edges, and protocol groupings as visually distinct clusters. A synchronized packet list remains available as a secondary view, sharing filter state with the topology so that structural and tabular inspection function as one continuous workflow. The system parses PCAP and PCAPNG formats, dissects over 90 protocols, and renders the topology through Three.js. The paper argues that the third spatial dimension is not merely aesthetic but analytically meaningful: it reveals density, clustering, host centrality, and communication scale that are difficult to perceive in list-only tools.
Exploring Europa, one of Jupiter's icy moons, is crucial for advancing our understanding of extraterrestrial geology and potential habitability. At present, study of gravity anomalies represents the best way to interrogate Europa's seafloor; however, current and expected global gravity models are insufficient for detecting and characterizing specific geologic features due to their coarse resolution. This study aims to determine whether Line-of-Sight (LoS) gravity signatures derived from Doppler residuals can be used to identify specific geological features on Europa's seafloor, such as mountain ranges, valleys, impact basins, rift zones, and subduction zones. Here, we assess the detectability of these features and evaluate whether the resolution from Europa Clipper would be sufficient to distinguish them. Our findings indicate that the expected LoS Doppler residual data likely will not provide sufficient resolution to differentiate between various geological formations on Europa's seafloor, primarily due to the spatial scale of the expected features compared to the spacecraft's distance from the surface. These limitations suggest that gravity signatures alone may not offer enough information for the interpretation of Europa's seafloor geology.
The λ -fold complete 3-uniform hypergraph on v vertices has the edge multiset consisting of λ copies of each 3-element subset of its vertex set. A tight 6-cycle, denoted TC_6 , is a hypergraph with vertex set {a,b,c,d,e,f} and edge set {{a,b,c}, {b,c,d}, {c,d,e}, {d,e,f}, {e,f,a}, {f,a,b}} . We give necessary and sufficient conditions on v for the existence of a TC_6 -decomposition of the λ -fold complete 3-uniform hypergraph on v vertices for any positive integer λ .
Tall fescue-dominated pasturelands are widespread in the eastern United States and typically lack substantial plant diversity. Establishing native wildflowers into tall fescue pastures has the potential to benefit bee populations and boost pollinator ecosystem services. In this study, tall fescue pastures at five on-farm sites in Virginia, USA, were planted with wildflowers native to North America and paired with sites with conventional tall fescue pastures. Honeybee apiaries were established at the ten locations, and variables related to hive strength were measured over two years. The main study objectives were to: (1) compare metrics of hive strength between diversified and conventional pastures, (2) determine whether honeybees used native-sown wildflowers as a source of pollen, and (3) explore whether native-sown wildflowers were visited more by honeybees and other pollinators compared with nonnative, unsown forbs. Diversified pastures had many more plant species and blooms compared with conventional pastures, but this had little effect on hive parameters. Pollen DNA metabarcoding revealed that honeybee diets were similar regardless of whether hives were associated with diversified or conventional pastures. Honeybees foraged mostly on plants in the surrounding landscape—especially white clover (Trifolium repens) and less so on native wildflowers. Native-sown wildflowers received more visits from native pollinators, however. We hypothesize that the native-sown wildflowers had little impact on hive strength metrics because honeybees had access to abundant, white clover blooms and other flowering species in these landscapes. Native wildflowers that bloom in late summer/early autumn after white clover blooms diminish may be of greater value to honeybees in pasture settings.
