Skip to main content
U.S. flag

An official website of the United States government

Articles

Browse more than 65,000 articles authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.

Filter Total Items: 78946

First observation of the ground-state electron-capture of 40K First observation of the ground-state electron-capture of 40K

Potassium-40 is a widespread, naturally occurring isotope whose radioactivity impacts estimated geological ages spanning billions of years, nuclear structure theory, and subatomic rare-event searches—including those for dark matter and neutrinoless double-beta decay. The decays of this long-lived isotope must be precisely known for its use as a geochronometer, and to account for its...
Authors
L. Hariasz, M. Stukel, P.C.F. Di Stefano, B.C. Rasco, K.P. Rykaczewski, N.T. Brewer, D.W. Stracener, Y. Liu, Z. Gai, C. Rouleau, J. B. Carter, J. Kostensalo, J. Suhonen, H. Davis, E.D. Lukosi, K.C. Goetz, R.K. Grzywacz, M. Mancuso, F. Petricca, A. Fijalkowska, M. Wolinska-Cichocka, J. Ninkovic, P. Lechner, R.B. Ickert, Leah E. Morgan, P.R. Renne, I. Yavin

Rare 40K decay with implications for fundamental physics and geochronology Rare 40K decay with implications for fundamental physics and geochronology

Potassium-40 is a widespread, naturally occurring isotope whose radioactivity impacts subatomic rare-event searches, nuclear structure theory, and estimated geological ages. A predicted electron-capture decay directly to the ground state of argon-40 has never been observed. The KDK (potassium decay) collaboration reports strong evidence of this rare decay mode. A blinded analysis reveals...
Authors
M. Stukel, L. Hariasz, P.C.F. Di Stefano, B.C. Rasco, K.P. Rykaczewski, N.T. Brewer, D.W. Stracener, Y. Liu, Z. Gai, C. Rouleau, J. B. Carter, J. Kostensalo, J. Suhonen, H. Davis, E.D. Lukosi, K.C. Goetz, R.K. Grzywacz, M. Mancuso, F. Petricca, A. Fijalkowska, M. Wolinska-Cichocka, J. Ninkovic, P. Lechner, R.B. Ickert, Leah E. Morgan, P.R. Renne, I. Yavin

Variation in herbivore space use: Comparing two savanna ecosystems with different anthrax outbreak patterns in southern Africa Variation in herbivore space use: Comparing two savanna ecosystems with different anthrax outbreak patterns in southern Africa

Background The distribution of resources can affect animal range sizes, which in turn may alter infectious disease dynamics in heterogenous environments. The risk of pathogen exposure or the spatial extent of outbreaks may vary with host range size. This study examined the range sizes of herbivorous anthrax host species in two ecosystems and relationships between spatial movement...
Authors
Yen-Hua Huang, Norman Owen-Smith, Michelle D. Henley, J. Werner Kilian, Pauline L. Kamath, Sunday O. Ochai, Henriette van Heerden, John K.E. Mfune, Wayne M. Getz, Wendy Christine Turner

Ten best practices for effective phenological research Ten best practices for effective phenological research

The number and diversity of phenological studies has increased rapidly in recent years. Innovative experiments, field studies, citizen science projects, and analyses of newly available historical data are contributing insights that advance our understanding of ecological and evolutionary responses to the environment, particularly climate change. However, many phenological data sets have
Authors
Richard Primack, Amanda S. Gallinat, Elizabeth R. Ellwood, Theresa M. Crimmins, Mark D. Schwartz, Michelle Staudinger, Abraham J. Miller-Rushing

Satellite tracking reveals use of Biscayne National Park by sea turtles tagged in multiple locations Satellite tracking reveals use of Biscayne National Park by sea turtles tagged in multiple locations

Although historical observations date back to the 1800’s, there is little information on sea turtle occupancy within Biscayne National Park (BNP). The park is located along the Florida reef tract and is dominated by the Gulfstream, which acts as a corridor for many marine animals. Here we used satellite telemetry to determine areas of use in BNP for two species of imperiled sea turtles...
Authors
Kristen Hart, Allison Benscoter, Haley M. Turner, Michael Cherkiss, Andrew Crowder, Jacquelyn C. Guzy, David Roche, Christopher R. Sasso, Glenn D. Goodwin, Derek A. Burkholder

Variations in climate drive behavior and survival of small desert tortoises Variations in climate drive behavior and survival of small desert tortoises

In the Mojave Desert, timing and amounts of precipitation profoundly affect availability of water and annual plant foods necessary for the threatened Agassiz’s desert tortoise (Gopherus agassizii) to survive, especially during prolonged droughts. As part of recovery actions to increase declining populations, we translocated 83 juvenile and young desert tortoises raised in head-start pens...
Authors
Kristin H. Berry, Jeremy S Mack, Kemp M. Anderson

Vertebrate population changes induced by hunting in Amazonian sustainable-use protected areas Vertebrate population changes induced by hunting in Amazonian sustainable-use protected areas

The purported sustainability of sustainable-use reserves (SURs) has been questioned in recent decades due to anthropogenic disturbance, including widespread game hunting. A fuller understanding of the drivers of harvest-induced game population changes in SURs is needed to inform this debate. We deployed 720 camera traps around 100 local communities both inside and outside nine SURs in...
Authors
Ricardo Sampaio, Ronaldo G. Morato, J. Andrew Royle, Mark I. Abrahams, Carlos A. Peres, Adriano G. Chiarello

Estuarine salinity extremes: Using the Coastal Salinity Index to quantify the role of droughts, floods, hurricanes, and freshwater flow alteration Estuarine salinity extremes: Using the Coastal Salinity Index to quantify the role of droughts, floods, hurricanes, and freshwater flow alteration

In the face of accelerating climate change, advancing understanding of how extreme climatic events influence estuarine salinities can help to inform resource management. Extreme salinities driven by droughts, hurricanes, floods, and freshwater flow alterations can lead to ecological transformations in estuarine ecosystems. Here, we applied the Coastal Salinity Index (CSI; Conrads and...
Authors
Laura Feher, Michael Osland, Christopher Swarzenski

Incorporating metapopulation dynamics to inform invasive species management: Evaluating bighead and silver carp control strategies in the Illinois River Incorporating metapopulation dynamics to inform invasive species management: Evaluating bighead and silver carp control strategies in the Illinois River

1. Invasive species management can benefit from predictive models that incorporate spatially explicit demographics and dispersal to guide resource allocation decisions. 2. We used invasive bigheaded carps (Hypophthalmichthys spp.) in the Illinois River, USA as a case study to create a spatially explicit model to evaluate the allocation of future management efforts. Specifically, we...
Authors
Jahn Kallis, Richard A. Erickson, David P. Coulter, Alison A. Coulter, Marybeth K. Brey, Matt Catalano, John M. Dettmers, James E. Garvey, Kevin Irons, Elizabeth A. Marschall, Kenneth A Rose, Mark L. Wildhaber, David C. Glover

Comparison of co-recorded analog and digital systems for characterization of responses and uncertainties Comparison of co-recorded analog and digital systems for characterization of responses and uncertainties

One of the most prominent challenges related to legacy seismic data is determining how these data can be appropriately used in modern research applications. The wide variety of instrumentation used in the analog era, the format of recording on paper wrapped around a helicorder drum, and limited metadata information introduces ambiguities that are not typical of modern digital data...
Authors
Thomas A. Lee, Adam T. Ringler, Robert E. Anthony, Miaki Ishii

Tree-ring derived avalanche frequency and climate associations in a high-latitude, maritime climate Tree-ring derived avalanche frequency and climate associations in a high-latitude, maritime climate

Snow avalanches are a natural hazard in mountainous areas worldwide with severe impacts that include fatalities, damage to infrastructure, disruption to commerce, and landscape disturbance. Understanding long-term avalanche frequency patterns, and associated climate and weather influences, improves our understanding of how climate change may affect avalanche activity. We used...
Authors
Erich H. Peitzsch, Eran Hood, John Harley, Daniel Kent Stahle, Nicholas E. Kichas, Gabriel J. Wolken
Was this page helpful?