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1. First description of migratory behavior of humpback whales from an Antarctic feeding ground to a tropical calving ground

   https://doi.org/10.1186/s40317-021-00266-8  

   Modest, Michelle; Irvine, Ladd; Andrews-Goff, Virginia; Gough, William; Johnston, David; Nowacek, Douglas; Pallin, Logan; Read, Andrew; Moore, Reny Tyson; Friedlaender, Ari (October 2021, Animal Biotelemetry)

   Abstract BackgroundDespite exhibiting one of the longest migrations in the world, half of the humpback whale migratory cycle has remained unexamined. Until now, no study has provided a continuous description of humpback whale migratory behavior from a feeding ground to a calving ground. We present new information on satellite-derived offshore migratory movements of 16 Breeding Stock G humpback whales from Antarctic feeding grounds to South American calving grounds. Satellite locations were used to demonstrate migratory corridors, while the impact of departure date on migration speed was assessed using a linear regression. A Bayesian hierarchical state–space animal movement model (HSSM) was utilized to investigate the presence of Area Restricted Search (ARS) en route. Results35,642 Argos locations from 16 tagged whales from 2012 to 2017 were collected. The 16 whales were tracked for a mean of 38.5 days of migration (range 10–151 days). The length of individually derived tracks ranged from 645 to 6381 km. Humpbacks were widely dispersed geographically during the initial and middle stages of their migration, but convened in two convergence regions near the southernmost point of Chile as well as Peru’s Illescas Peninsula. The state–space model showed almost no instances of ARS along the migratory route. The linear regression assessing whether departure date affected migration speed showed suggestive but inconclusive support for a positive trend between the two variables. Results suggestive of stratification by sex and reproductive status were found for departure date and route choice. ConclusionsThis multi-year study sets a baseline against which the effects of climate change on humpback whales can be studied across years and conditions and provides an excellent starting point for the investigation into humpback whale migration. 

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2. Boots on the Ground at Yaxnohcah: Ground-Truthing Lidar in a Complex Tropical Landscape

   https://doi.org/10.7183/2326-3768.4.3.314  

   Reese-Taylor, Kathryn; Hernández, Armando Anaya; Esquivel, F. C.; Monteleone, Kelly; Uriarte, Alejandro; Carr, Christopher; Acuña, Helga Geovannini; Fernandez-Diaz, Juan Carlos; Peuramaki-Brown, Meaghan; Dunning, Nicholas (August 2016, Advances in Archaeological Practice)

   Este trabajo propone un método de muestreo a fin de contrastar en el terreno los datos obtenidos a partir de imágenes LiDAR, que permitan al investigador verificar y/o predecir la precisión de los resultados sobre un área mayor. El estudio de caso aquí presentado se centra en el sitio de Yaxnohcah, ubicado en la Meseta Cárstica Central de la península de Yucatán. Está área se caracteriza por presentar una variedad de densos bosques tropicales húmedos y zonas de vegetación de humedal con pocos accesos de caminos y brechas. Para este estudio se seleccionaron veintiún bloques de 100 por 100 metros del área, que comprendió una muestra estratificada del 10 por ciento, e incluyeron ejemplos de varias zonas de vegetación distinta. Se realizó un recorrido de superficie por transectos a lo largo de los bloques, registrándose dos tipos de errores. Los Errores del Tipo 1 consisten de rasgos culturales identificados en campo, pero que no aparecen en el los Modelos Digital de Elevación (MDE) o en el Modelo de Superficie Digital (MSE). Los Errores de Tipo 2 consisten en rasgos que parecen culturales en el MDE o MSE, pero que en realidad son causadas por diferentes tipos de vegetación. De manera concurrente, realizamos un extenso reconocimiento de la vegetación en cada bloque, identificando las principales especies presentes, las diferentes alturas de dosel, así como las características generales de la topografía y los suelos. Los resultados del método de contrastación en el terreno demuestran que los datos lidar son sumamente confiables y es posible utilizar una muestra a fin de evaluar la precisión, la veracidad y la certidumbre de los datos sobre un área mayor. 

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3. BeetleVerse: A study on taxonomic classification of ground beetles

   Rayeed, S_M; East, Alyson; Stevens, Sam; Record, Sydne; Stewart, Charles V (July 2025, arXiv)

   Ground beetles are a highly sensitive and speciose biolog- ical indicator, making them vital for monitoring biodiver- sity. However, they are currently an underutilized resource due to the manual effort required by taxonomic experts to perform challenging species differentiations based on sub- tle morphological differences, precluding widespread ap- plications. In this paper, we evaluate 12 vision models on taxonomic classification across four diverse, long-tailed datasets spanning over 230 genera and 1769 species, with images ranging from controlled laboratory settings to chal- lenging field-collected (in-situ) photographs. We further ex- plore taxonomic classification in two important real-world contexts: sample efficiency and domain adaptation. Our re- sults show that the Vision and Language Transformer com- bined with an MLP head is the best performing model, with 97% accuracy at genus and 94% at species level. Sample efficiency analysis shows that we can reduce train data re- quirements by up to 50% with minimal compromise in per- formance. The domain adaptation experiments reveal sig- nificant challenges when transferring models from lab to in-situ images, highlighting a critical domain gap. Overall, our study lays a foundation for large-scale automated tax- onomic classification of beetles, and beyond that, advances sample-efficient learning and cross-domain adaptation for diverse long-tailed ecological datasets. 

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4. Can a ground‐based vehicle hear the shape of a room?

   https://doi.org/10.1111/sapm.12581  

   Boutin, Mireille; Kemper, Gregor (July 2023, Studies in Applied Mathematics)

   Abstract Assume that a ground‐based vehicle moves in a room with walls or other planar surfaces. Can the vehicle reconstruct the positions of the walls from the echoes of a single sound event? We assume that the vehicle carries some microphones and that a loudspeaker is either also mounted on the vehicle or placed at a fixed location in the room. We prove that the reconstruction is almost always possible if (1) no echoes are received from floors, ceilings, or sloping walls and the vehicle carries at least three noncollinear microphones, or if (2) walls of any inclination may occur, the loudspeaker is fixed in the room and there are four noncoplanar microphones. The difficulty lies in the echo‐matching problem: How to determine which echoes come from the same wall. We solve this by using a Cayley–Menger determinant. Our proofs use methods from computational commutative algebra. 

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5. A Positive Cloud‐to‐Ground Flash Caused by a Sequence of Bidirectional Leaders that Served to Form a Ground‐Reaching Branch of a Pre‐Existing Horizontal Channel

   https://doi.org/10.1029/2020JD033653  

   Wu, Bin; Lyu, Weitao; Qi, Qi; Ma, Ying; Chen, Lyuwen; Jiang, Ruijiao; Zhu, Yanan; Rakov, Vladimir A. (June 2021, Journal of Geophysical Research: Atmospheres)

   Abstract High‐speed video and electric field change data were used to analyze the initiation and propagation of four predominantly vertical bidirectional leaders making connection to a predominantly horizontal channel previously formed aloft. The four bidirectional leaders sequentially developed along the same path and served to form a positive branch of the horizontal in‐cloud channel, which became a downward positive leader producing a 135‐kA positive cloud‐to‐ground (+CG) return stroke. The positive (lower) end of each bidirectional leader elongated abruptly at the time of connection of the negative (upper) end to the pre‐existing channel aloft. Thirty‐six negative streamer‐like filaments (resembling recently reported “needles”) extended sideways over ∼110 to 740 m from the pre‐existing horizontal channel at speeds of ∼0.5 to 1.9 × 10⁷ m/s, in response to the injection of negative charge associated with the +CG. 

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