bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of ring-tailed lemur Lemur catta populations in south-western Madagascar
Authors: Randrianjaka Sylvain , Calkins Samantha , Sefczek Timothy M. , Frasier Cynthia L. , Randriamampionona Richard , Rakotoniaina Jean Claude , de Roland Lily-Arison R. , Baden Andrea L. , Louis Edward E. 
Published: May 2023

AbstractAnthropogenic activities are negatively affecting the flora and fauna of Madagascar, including its Endangered flagship lemur species, the ring-tailed lemur Lemur catta. Population numbers at some sites are rapidly declining, yet much of the species' habitat is insufficiently surveyed. Because widespread population assessments are critical to guiding conservation management strategies, additional data are needed to monitor L. catta population trends and to identify the limits of their geographical range. Here we report survey results confirming the presence of this species at 65 of 83 sites in southern and south-western Madagascar, including three subpopulations that were previously considered likely to be locally extinct. We identified a minimum of 792 L. catta individuals (summing only maximum group sizes at each site) and as many as 1,221 individuals (using estimated population counts). These findings help refine the distribution of L. catta and reaffirm their presence in areas of their historical geographical range. Identifying species occupancy at sites such as these provides valuable data to support species conservation, but also highlights the need for additional surveys throughout the range of the species.
Non‐Synchronous Rotation on Europa Driven by Ocean Currents
Authors: Ashkenazy Yosef , Tziperman Eli , Nimmo Francis 
Published: May 2023

AbstractIt has been suggested that the ice shell of Jupiter's moon Europa may drift non‐synchronously due to tidal torques. Here we argue that torques applied by the underlying ocean are also important and can result in non‐synchronous rotation. The resulting spin rate can be slightly slower than the synchronous angular rate that would have kept the same point of the ice shell facing Jupiter. We develop an ice shell rotation model, driven by ocean stress calculated using a high‐resolution state‐of‐the‐art ocean general circulation model, and take into account the viscoelastic deformation of the ice shell. We use the ice shell model results together with observed limits on the ice shell drift speed to constrain ice shell parameters such as effective viscosity, which is currently uncertain by at least four orders of magnitude. Our results suggest, at best, sluggish ice shell convection. Depending on the relaxation time scale of the ice shell and on the ocean currents, the ice shell may exhibit negligible drift, constant drift, or oscillatory drift superimposed on random fluctuations. The expected rotation rate exceeds ∼30 m/yr; future spacecraft observations can be used to test these predictions and yield insight into the properties of the ice shell and underlying ocean.
Greenland Ice Sheet Ice Slab Expansion and Thickening
Authors: Jullien N. , Tedstone A. J. , Machguth H. , Karlsson N. B. , Helm V. 
Published: May 2023

AbstractWe use airborne accumulation radar data acquired over the Greenland Ice Sheet between 2002 and 2018 to identify changes in ice slab extent and thickness. We show that ice slabs several meters thick were already present at least as early as 2002. Between 2012 and 2018, they expanded by 13,400–17,600 inland, or 37%–44%. Our results document that the extremely warm summer of 2012 produced near‐surface ice layers at higher elevations, enabling ice slabs to develop with only moderate melting in the following summers. With repeat flights along a transect in southwest Greenland, we show that moderate melting primarily causes slab thickening through uniform accretion on top of the ice slabs, while large melting events can also trigger localized accretion below existing ice slabs.
Tropical Cyclone Stalling Shifts Northward and Brings Increasing Flood Risks to East Asian Coast
Authors: Zhang Lujia , Cheng Tat Fan , Lu Mengqian , Xiong Rui , Gan Jianping 
Published: May 2023

AbstractTropical cyclone (TC) stalling has been widely perceived to yield a greater threat of flooding. Understanding the effect of stalling and its long‐term trends will enhance adaptation strategies to cyclone‐associated disasters. We show that stalling prolongs western North Pacific TCs to live 24 hr longer and produces 23% greater 24‐hr rainfall accumulations in a more concentrated area, which is more prominent over a 72‐hr rolling period. More importantly, we discover a northward migration of TC stalling (∼0.7°N decade−1) over 1979–2020, bringing increasingly higher flood risks to the highly‐populated East Asian coast. Further diagnoses suggest the role of binary cyclone interactions in TC stalling, whereby the second larger TC slows down the smaller one by weakening the northwestward steering flows. The northward shift of TC stalling can be explained by a similar trend in binary TC cases and environmental fields. Our findings are robust across various best track and precipitation products.
Short Time‐Scale Variability of Ammonium, Nitrate, and Nitrogen Loss Dynamics During an Upwelling‐Induced Bloom at the Oregon Shelf
Authors: Segura‐Noguera M. , Álvarez‐Salgado X. A. , Siedlecki S. , Hales B. R. 
Published: May 2023

AbstractAmmonium, a key intermediate nutrient, is typically low to undetectable on the Oregon coast, particularly as active upwelling delivers high onshore flow of ammonium‐poor waters. However, during bloom and post‐bloom conditions large ammonium concentrations and uptake rates have been described. High‐frequency on board nitrate + nitrite and ammonium analysis synchronized with continuous data from a towed profiling vehicle (equipped with in situ temperature, salinity, dissolved oxygen, and beam attenuation sensors), allowed us to describe coupled high‐resolution physico‐chemical dynamics of inorganic nitrogen in seven cross‐shelf transects, over several days, during an active phytoplankton bloom following cessation of upwelling favorable winds. We present first‐of‐their‐kind high‐resolution cross‐sections showing a build‐up, both within a thin plume of onshore‐originated water, and in mid‐to‐bottom on‐shore water columns, from undetectable values to up to 8 µM of ammonium. The plume extended across the shelf at mid‐depth and was identified in all transects. We also detected a decrease of nitrate in distinct water masses close to the mid‐shelf seabed, associated with low dissolved oxygen, and identified and quantified the amount of nitrogen lost. We found that nitrogen loss was minimal on the first days of relaxation conditions, and increased up to 12 μM off Newport. Combining nitrogen fluxes from benthic incubation chambers and N loss calculated with the NO tracer, we estimated that denitrification in sediments could not account for all N loss, requiring 22%–86% to occur elsewhere. Close association of N loss with particle‐rich, low O2 waters suggests the possibility that particle‐aggregate micro‐environments could provide additional sites for water column denitrification.
How Moisture Shapes Low‐Level Radiative Cooling in Subsidence Regimes
Authors: Fildier B. , Muller C. , Pincus R. , Fueglistaler S. 
Published: May 2023

AbstractRadiative cooling of the lowest atmospheric levels is of strong importance for modulating atmospheric circulations and organizing convection, but detailed observations and a robust theoretical understanding are lacking. Here we use unprecedented observational constraints from subsidence regimes in the tropical Atlantic to develop a theory for the shape and magnitude of low‐level longwave radiative cooling in clear‐sky, showing peaks larger than 5–10 K/day at the top of the boundary layer. A suite of novel scaling approximations is first developed from simplified spectral theory, in close agreement with the measurements. The radiative cooling peak height is set by the maximum lapse rate in water vapor path, and its magnitude is mainly controlled by the ratio of column relative humidity above and below the peak. We emphasize how elevated intrusions of moist air can reduce low‐level cooling, by sporadically shading the spectral range which effectively cools to space. The efficiency of this spectral shading depends both on water content and altitude of moist intrusions; its height dependence cannot be explained by the temperature difference between the emitting and absorbing layers, but by the decrease of water vapor extinction with altitude. This analytical work can help to narrow the search for low‐level cloud patterns sensitive to radiative‐convective feedbacks: the most organized patterns with largest cloud fractions occur in atmospheres below 10% relative humidity and feel the strongest low‐level cooling. This motivates further assessment of favorable conditions for radiative‐convective feedbacks and a robust quantification of corresponding shallow cloud dynamics in current and warmer climates.
Effects of Lake Baikal on Summertime Precipitation Climatology Over the Lake Surface
Authors: Lee Hyunho , Ganbat Gantuya , Jin Han‐Gyul , Seo Jaemyeong Mango , Moon Sungju , Bok Hyejeong , Baik Jong‐Jin 
Published: May 2023

AbstractThis study investigates the impacts of Lake Baikal, the largest by volume and the deepest freshwater lake in the world, on its nearby precipitation climate. Satellite observations and a reanalysis data set reveal that summertime precipitation amount is smaller over Lake Baikal than around it. A 15‐year regional climate simulation at a cloud‐resolving scale supports the smaller precipitation, and another simulation in which the lake is replaced by forest shows that the lake reduces summertime precipitation over it by 15%. The lake decreases daytime near‐surface air temperature, resulting in more convectively stable atmosphere over the lake. Latent heat flux is reduced along with the weakened convection, and the lower‐level moisture convergence and upper‐level moisture divergence over the lake are weakened.
Turning Lakes Into River Gauges Using the LakeFlow Algorithm
Authors: Riggs Ryan M. , Allen George H. , Brinkerhoff Craig B. , Sikder Md. Safat , Wang Jida 
Published: May 2023

AbstractRivers and lakes are intrinsically connected waterbodies yet they are rarely used to hydrologically constrain one another with remote sensing. Here we begin to bridge the gap between river and lake hydrology with the introduction of the LakeFlow algorithm. LakeFlow uses river‐lake mass conservation and observations from the Surface Water and Ocean Topography (SWOT) satellite to provide river discharge estimates of lake and reservoir inflows and outflows. We test LakeFlow performance at three lakes using a synthetic SWOT data set assuming the maximum measurement errors defined by the mission science requirements, and we include modeled lateral inflow and lake evaporation data to further constrain the mass balance. We find that LakeFlow produces promising discharge estimates (median Nash‐Sutcliffe efficiency = 0.88, relative bias = 14%). LakeFlow can inform water resources management by providing global lake inflow and outflow estimates, highlighting a path for recognizing rivers and lakes as an interconnected system.
Spatial Resolution in Inverse Problems: The EZIE Satellite Mission
Authors: Madelaire Michael , Laundal Karl , Gjerloev Jesper , Hatch Spencer , Reistad Jone , Vanhamäki Heikki , Waters Colin , Ohma Anders , Mesquita Rafael , Merkin Viacheslav 
Published: May 2023

AbstractInverse modeling has become one of the primary methods for studying ionospheric electrodynamics, especially when using magnetic field measurements from below the ionosphere. We present a method for quantifying the spatial resolution in an inverse model for non‐uniformly sampled spatial data. This method provides a tool for assessing if a model can resolve the physical phenomena of interest. We quantify the spatial resolution for the Spherical Elementary Current System basis functions to model the ionospheric dynamics. Our results apply to models with spatially confined model parameters, unlike spherical harmonics where the model parameters describe the amplitude of global surface functions. The method is demonstrated for the upcoming Electrojet Zeeman Imaging Explorer cubesat mission which will provide spatially distributed remote sensing measurements of the magnetic field in the mesosphere. We show that, including measurements from a single ground magnetometer can significantly improve the spatial resolution. However, the impact of including a ground magnetometer depends on the relative position of the station with respect to the mesospheric measurements. In addition, a method for reducing two regularization parameters to one is presented. Reducing the amount of regularization parameters simplifies the optimization problem and facilitates a fair comparison between the models with and without a ground magnetometer.
Frequency unlocking-based MEMS bifurcation sensors
Authors: Qiao Yan , Shi Zhan , Xu Yutao , Wei Xueyong , Elhady Alaaeldin , Abdel-Rahman Eihab , Huan Ronghua , Zhang Wenming 
Published: May 2023

AbstractMEMS resonators exhibit rich dynamic behaviors under the internal resonance regime. In this work, we present a novel MEMS bifurcation sensor that exploits frequency unlocking due to a 1:3 internal resonance between two electrostatically coupled micro-resonators. The proposed detection mechanism allows the sensor to operate in binary (digital) and analog modes, depending on whether the sensor merely detects a significant jump event in the peak frequency upon unlocking or measures the shift in the peak frequency after unlocking and uses it in conjunction with a calibration curve to estimate the corresponding change in stimulus. We validate the success of this sensor paradigm by experimentally demonstrating charge detection. High charge resolutions are achieved in binary mode, up to 0.137 fC, and in analog mode, up to 0.01 fC. The proposed binary sensor enables extraordinarily high detection resolutions due to the excellent frequency stability under internal resonance and the high signal-to-noise ratio of the shift in peak frequency. Our findings offer new opportunities for high-performance ultrasensitive sensors.
Dynamic control of high-voltage actuator arrays by light-pattern projection on photoconductive switches
Authors: Bacheva Vesna , Firouzeh Amir , Leroy Edouard , Balciunaite Aiste , Davila Diana , Gabay Israel , Paratore Federico , Bercovici Moran , Shea Herbert , Kaigala Govind 
Published: May 2023

AbstractThe ability to control high-voltage actuator arrays relies, to date, on expensive microelectronic processes or on individual wiring of each actuator to a single off-chip high-voltage switch. Here we present an alternative approach that uses on-chip photoconductive switches together with a light projection system to individually address high-voltage actuators. Each actuator is connected to one or more switches that are nominally OFF unless turned ON using direct light illumination. We selected hydrogenated amorphous silicon (a-Si:H) as our photoconductive material, and we provide a complete characterization of its light to dark conductance, breakdown field, and spectral response. The resulting switches are very robust, and we provide full details of their fabrication processes. We demonstrate that the switches can be integrated into different architectures to support both AC and DC-driven actuators and provide engineering guidelines for their functional design. To demonstrate the versatility of our approach, we demonstrate the use of the photoconductive switches in two distinctly different applications—control of µm-sized gate electrodes for patterning flow fields in a microfluidic chamber and control of cm-sized electrostatic actuators for creating mechanical deformations for haptic displays.
Impedance spectroscopy of the cell/nanovolcano interface enables optimization for electrophysiology
Authors: Maïno Nicolas , Bertsch Arnaud , Renaud Philippe 
Published: May 2023

AbstractVolcano-shaped microelectrodes have demonstrated superior performance in measuring attenuated intracellular action potentials from cardiomyocyte cultures. However, their application to neuronal cultures has not yet yielded reliable intracellular access. This common pitfall supports a growing consensus in the field that nanostructures need to be pitched to the cell of interest to enable intracellular access. Accordingly, we present a new methodology that enables us to resolve the cell/probe interface noninvasively through impedance spectroscopy. This method measures changes in the seal resistance of single cells in a scalable manner to predict the quality of electrophysiological recordings. In particular, the impact of chemical functionalization and variation of the probe’s geometry can be quantitatively measured. We demonstrate this approach on human embryonic kidney cells and primary rodent neurons. Through systematic optimization, the seal resistance can be increased by as much as 20-fold with chemical functionalization, while different probe geometries demonstrated a lower impact. The method presented is therefore well suited to the study of cell coupling to probes designed for electrophysiology, and it is poised to contribute to elucidate the nature and mechanism of plasma membrane disruption by micro/nanostructures.
Deep sampling of gRNA in the human genome and deep-learning-informed prediction of gRNA activities
Authors: Zhang Heng , Yan Jianfeng , Lu Zhike , Zhou Yangfan , Zhang Qingfeng , Cui Tingting , Li Yini , Chen Hui , Ma Lijia 
Published: May 2023

AbstractLife science studies involving clustered regularly interspaced short palindromic repeat (CRISPR) editing generally apply the best-performing guide RNA (gRNA) for a gene of interest. Computational models are combined with massive experimental quantification on synthetic gRNA-target libraries to accurately predict gRNA activity and mutational patterns. However, the measurements are inconsistent between studies due to differences in the designs of the gRNA-target pair constructs, and there has not yet been an integrated investigation that concurrently focuses on multiple facets of gRNA capacity. In this study, we analyzed the DNA double-strand break (DSB)-induced repair outcomes and measured SpCas9/gRNA activities at both matched and mismatched locations using 926,476 gRNAs covering 19,111 protein-coding genes and 20,268 non-coding genes. We developed machine learning models to forecast the on-target cleavage efficiency (AIdit_ON), off-target cleavage specificity (AIdit_OFF), and mutational profiles (AIdit_DSB) of SpCas9/gRNA from a uniformly collected and processed dataset by deep sampling and massively quantifying gRNA capabilities in K562 cells. Each of these models exhibited superlative performance in predicting SpCas9/gRNA activities on independent datasets when benchmarked with previous models. A previous unknown parameter was also empirically determined regarding the “sweet spot” in the size of datasets used to establish an effective model to predict gRNA capabilities at a manageable experimental scale. In addition, we observed cell type-specific mutational profiles and were able to link nucleotidylexotransferase as the key factor driving these outcomes. These massive datasets and deep learning algorithms have been implemented into the user-friendly web service http://crispr-aidit.com to evaluate and rank gRNAs for life science studies.
Scientific echosounder data provide a predator’s view of Antarctic krill (Euphausia superba)
Authors: Cox M. J. , Smith A. J. R. , Brierley A. S. , Potts J. M. , Wotherspoon S. , Terauds A. 
Published: May 2023

AbstractRaw acoustic data were collected in East Antarctica from the RSV Aurora Australis during two surveys: the Krill Availability, Community Trophodynamics and AMISOR Surveys (KACTAS) and the Krill Acoustics and Oceanography Survey (KAOS) in the East Antarctic (centre coordinate 66.5° S, 63° E). The KACTAS survey was conducted between 14th to 21st January and 2001, and the KAOS survey was conducted between 16 January and 1 February 2003. We examine the Antarctic krill (Euphausia superba) component of these surveys and provide scientific echosounder (EK500 and EK60) data collected at 38, 120 and 200 kHz, cold water (−1 °C) echosounder calibration parameters and accompanying krill length frequency distributions obtained from trawl data. We processed the acoustic data to apply calibration values and remove noise. The processed data were used to isolate echoes arising from swarms of krill and to estimate metrics for each krill swarm, including internal density and individual swarm biomass. The krill swarm data provide insights to a predators’ views of krill distribution and density.
Experimental investigation on the hazard of geyser created by an entrapped air release in baffle-drop shafts
Authors: Yang Qinghua , Yang Qian 
Published: May 2023

AbstractThe geyser phenomenon seriously threatens the safe operation of deep tunnel drainage systems and drop shaft structural safety. To simulate the geyser process in a baffle-drop shaft, a 1:50 scale model test system was used to research the response relationship between the geyser mechanism and test parameters such as water depth, inlet pressure, and inlet volume. The results show that the pressure in a baffle-drop shaft fluctuates sharply during the geyser process. This is caused by the release of a high-pressure air mass, and high-speed movement of the air–water mixture causes a local pressure imbalance in the drop shaft. A prediction formula for the maximum geyser height of a baffle-drop shaft was established by a multiple linear regression model. Geyser occurrence conditions for the baffle-drop shaft were proposed combined with the response relationship between different influence variables and geyser intensity. Except for the inlet pressure, submerged state of the baffles, and measured location, the hydrodynamic load on the bottom of the baffles is also related to the randomness of the air–water mixture jetted on the baffle bottom. The maximum hydrodynamic load on the baffle bottom during the geyser is 10 times the hydrodynamic load on the baffle surface under normal discharge conditions. This research provides a theoretical reference for the structural design and safe operation of baffle-drop shafts.
High-resolution microbiome analysis reveals exclusionary Klebsiella species competition in preterm infants at risk for necrotizing enterocolitis
Authors: Coleman Spencer , Unterhauser Katrin , Rezaul Karim , Ledala Nagender , Lesmes Stephanie , Caimano Melissa J. , Zhou Yanjiao , Jackson Eric , Gratalo Dawn , Driscoll Mark D. , Matson Adam P. 
Published: May 2023

AbstractIntestinal colonization with Klebsiella has been linked to necrotizing enterocolitis (NEC), but methods of analysis usually failed to discriminate Klebsiella species or strains. A novel ~ 2500-base amplicon (StrainID) that spans the 16S and 23S rRNA genes was used to generate amplicon sequence variant (ASV) fingerprints for Klebsiella oxytoca and Klebsiella pneumoniae species complexes (KoSC and KpSC, respectively) and co-occurring fecal bacterial strains from 10 preterm infants with NEC and 20 matched controls. Complementary approaches were used to identify cytotoxin-producing isolates of KoSC. Klebsiella species colonized most preterm infants, were more prevalent in NEC subjects versus controls, and replaced Escherichia in NEC subjects. Single KoSC or KpSC ASV fingerprinted strains dominated the gut microbiota, suggesting exclusionary Klebsiella competition for luminal resources. Enterococcus faecalis was co-dominant with KoSC but present infrequently with KpSC. Cytotoxin-producing KoSC members were identified in most NEC subjects and were less frequent in controls. Few Klebsiella strains were shared between subjects. We conclude that inter-species Klebsiella competition, within an environment of KoSC and E. faecalis cooperation, appears to be an important factor for the development of NEC. Preterm infants seem to acquire Klebsiella primarily through routes other than patient-to-patient transmission.