Rapid Decay Research Articles

Narrowband Solar-Blind Photodetection of the Plasmonic (In0.3Ga0.7)2O3 Detector via the Synergetic Enhancement of Small-Sized Ag-Nanoparticle Photoabsorbance and Surface Modification.

Currently, research on Ag nanoparticles (AgNPs) predominantly focuses on UV/visible photodetection and UV emission, seemingly overlooking the significance of Ag in enhancing deep ultraviolet photon detection. In this work, (In0.3Ga0.7)2O3 thin films were fabricated by plasma-enhanced chemical vapor deposition. Due to the unique photoabsorbance characteristic and better interaction with photons of small-sized AgNPs, they effectively suppress the UVB absorbance caused by energy band engineering in the (In0.3Ga0.7)2O3 thin film while enhancing photoabsorbance in UVC due to the surface plasmon effect. Therefore, under the synergistic effect of enhanced photon absorbance and hot electron transfer, the performance of the detector is significantly improved, and its responsivity (R), external quantum efficiency, and detectivity (D*) are 193 mA/W, approximately 100%, and 1014 Jones, respectively, at a bias of -6 V. The fast response time and decay time are 634.6 and 194.1 ms, respectively; the rapid decay facilitated by AgNPs is attributed to the increased indirect recombination rate. AgNPs exhibit excellent narrowband response characteristics and absorbance properties in specific wavelength bands for the InGaO photodetector. This research lays the foundation for the practical application of localized surface plasmon resonance-enhanced photon-sensing capabilities.

Solar Flare Effects in the Martian Ionosphere and Magnetosphere: 3‐D Time‐Dependent MHD‐MGITM Simulation and Comparison With MAVEN and MGS

AbstractA comprehensive modeling study has been conducted to investigate space weather effects at Mars during the 10 September 2017 solar flare, utilizing an integrated framework that combines the global magnetohydrodynamic (MHD) model and Mars Global Ionosphere‐Thermosphere Model (MGITM). This is the first time the thermosphere‐ionosphere‐magnetosphere system is self‐consistently simulated under realistic, time‐varying conditions. Our simulations align well with observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN). Recognizing that complexities due to highly disturbed upstream conditions and rotating crustal fields obscure solar flare effects in orbit‐to‐orbit comparisons, we perform controlled simulations of nonflare and flare cases and exploit their contrast to quantify spatiotemporal variations in flare impact. Our results highlight pronounced and rapid dayside ionospheric perturbations, contrasting with weaker and delayed nightside responses. Notably, in the topside ionosphere, and C densities increase primarily on the dayside below 300 km altitude, peaking with an increase of 20%–30%. The density shows a more significant increase of up to 50%, extending into the magnetosphere and nightside via plasma transport, increasing its total loss rate by 14%. We observe distinct altitude‐dependent patterns in dayside electron density enhancements in percent, characterized by a weakening with altitude and a rapid decay below 150 km in line with the flare development, and a gradual intensification between 150–300 km due to plasma transport and flare‐induced atmospheric upwelling. Earlier Mars Global Surveyor observations were limited to the low‐altitude pattern due to atmospheric expansion and missed the higher altitude variations observed by MAVEN.

Asymptotics of solutions of special second-order linear recurrencies with polynomial coefficients and boundary effects of polynomial filters

In this paper we prove that classical discrete orthogonal polynomials (Hahn polynomials on an equidistant grid with unit weights) of high degrees have extremely small values near the endpoints (we call this property “rapid decay near the endpoints”) but extremely large values between these grid points and their roots are very close to the grid points near the endpoints. These results imply important general boundary effects for stable linear polynomial filters (we call this property “rapid boundary attenuation”).Our results give interesting examples of nontrivial asymptotics of practically important solutions of special second-order linear recurrencies with polynomial coefficients studied by M.Petkovšek; to his memory we dedicate this paper.

Electronic Spectrum of α-Hydrofulvenyl Radical (C6H7), and a Simple and Accurate Recipe for Predicting Adiabatic Ionization Energies of Resonance-Stabilized Hydrocarbon Radicals.

Using a combination of resonant two-photon two-color ionization (R2C2PI) and laser-induced fluorescence/dispersed fluorescence spectroscopy, we have examined the 2A″ ← 2A″ transition of the resonance-stabilized α-hydrofulvenyl radical, produced from methylcyclopentadiene dimer in a jet-cooled discharge. Like the related 1,4-pentadienyl and cyclohexadienyl radicals, the α-hydrofulvenyl Ã-state lifetime is orders of magnitude shorter than the predicted f-value implies, indicative of rapid nonradiative decay. The transition is fully allowed by symmetry but considerably weakened by transition moment interference. Intensity borrowing among a' modes brings about static (i.e., Condon) and vibronic (i.e., Herzberg-Teller) moments of similar size, the result being a spectrum substantially less origin-dominated than is usually observed for extensively delocalized radicals. Twenty -state modes and twelve -state modes are identified with high confidence and assignments for several others are suggested. In addition, from a series of two-color appearance potential scans with the -state zero-point level serving as an intermediate, we obtain a field-free adiabatic ionization energy (AIE) of 7.012(1) eV. For a set of 21 resonance-stabilized radicals bearing 5 to 11 carbon atoms, it emerges that the field-free AIE obtained by R2C2PI methods under jet-cooled conditions lies very close to the average of B3LYP/6-311G++(d,p) (with harmonic zero-point energy) and CBS-QB3 0 K calculations, with a mean absolute deviation of only 0.010(7) eV (approximately 1 kJ/mol). On average, this represents a nearly 10-fold improvement in accuracy over CBS-QB3 predictions for the same set of radicals.

Toward High-Performance Electrochemical Ammonia Synthesis by Circumventing the Surface H-Mediated N2 Reduction.

The rapid performance decay with potentials is a significant obstacle to achieving an efficient electrocatalytic N2 reduction reaction (eNRR), which is typically attributed to competition from hydrogen evolution. However, the potential-dependent competitive behavior and reaction mechanism are still under debate. Herein, we theoretically defined N2 adsorption, H mediation, and H2 evolution as three crucial regions along the potentials by revisiting the potential-dependent competitive adsorption between N2 and H on FeN4 and RuN4 catalysts. We revealed that the surface H-mediated mechanism makes eNRR feasible at low potentials but introduces sluggish reaction kinetics, showing a double-edged sword nature. In view of this, we proposed a new possibility to achieve high-performance NH3 synthesis by circumventing the H-mediated mechanism, where the ideal catalyst should have a wide potential interval with N2-dominated adsorption to trigger direct eNRR. Using this mechanistic insight as a new criterion, we proposed a theoretical protocol for eNRR catalyst screening, but almost none of the theoretically reported electrocatalysts passed the assessment. This work not only illustrates the intrinsic mechanism behind the low-performance dilemma of eNRR but also points out a possible direction toward designing promising catalysts with high selectivity and high current density.

Group acceptance sampling plan based on truncated life tests for Type-I heavy-tailed Rayleigh distribution

This study on the Type-I heavy-tailed Rayleigh (TI-HTR) distribution is a special case of Type-I heavy-tailed (TI-HT) family of distributions was studied. The characteristics were derived, including the moment and its measures, quantile function, reliability measures, and other statistical properties as well as parameter estimation using the maximum likelihood method and penalized likelihood estimation. The behavior of its various functions were shown graphically. Analytically, we showed that model linearly grows near the origin and exhibits rapid exponential decay. However, the tail behavior cannot equal the traditional heavy-tail in the power law sense, hence it is called the type-I heavy-tail. Interestingly, we designed a group acceptance plan (GASP) and demonstrated usefulness with both assumed and maximum likelihood estimates. The GASP under the TI-HTR distribution is preferable when the parameter values are small. The distribution was used to model real-life data sets to justify its usefulness. The results of the application of the model to both COVID-19 and Cancer data showed that the model fits the two data better than the competing models and also suggest that inference from the model is better than those of the competitors. In estimating the parameters, the penalized likelihood procedure perform considerably better with minimum standard error of the estimates. From the Cramér-von Mises test results which guides against the heavy-tail sensitivity, the TI-HTR distribution offers a better model for fitting fast decaying exponential data since it has the least statistics in both datasets.

Dual‐Gradient Concentration Distribution in Sb−Cu Alloy Nanoarrays for Robust Sodium‐Ion Storage

AbstractAlloy‐type materials are attractive for anodes in sodium‐ion batteries (SIBs) owing to their high theoretical capacities and overall performance. However, the accumulation of stress/strain during repeated cycling results in electrode pulverization, leading to rapid capacity decay and eventual disintegration, thus hindering their practical applications. Herein, we report a 3D coral‐like Sb−Cu alloy nanoarray with gradient distribution of both elements. The array features a Sb‐rich bottom and a Cu‐rich top with increasing Sb and decreasing Cu concentrations from top to bottom. The former is the active component that provides the high capacity, whereas the latter serves as an inert additive that acts against volume variation. The gradual transition in composition within the electrode introduces a ladder‐type volume expansion effect, facilitating a smooth distribution and effective release of stress, thereby ensuring the wanted mechanical stability and structural integrity. The as‐developed nanoarray affords a high reversible capacity (460 mAh g−1 at 0.5 C), stable cycling (89 % retention over 120 cycles at 1.0 C), and superior rate capability (354 mAh g−1 at 10 C). The concentration dual‐gradient strategy paves a new pathway of designing alloy‐type materials forSIBs.

Whole genome re-sequencing reveals high altitude adaptation signatures and admixture in Ladakhi cattle

Ladakhi cattle, native to the high-altitude region of Ladakh in northern India (ranging from 3,000 to 5,000 m above sea level), have evolved unique genetic adaptations to thrive in harsh environmental conditions, such as hypoxia, extreme cold, and low humidity. This study explored the genome of Ladakhi cattle to investigate genetic structure, selection signatures, and adaptive mechanisms. Whole genome sequencing reads, generated on Illumina NovaSeq 6000 platform, were aligned to the Bos taurus reference genome with BWA-MEM. SNPs were identified and filtered using GATK and bcftools, and functionally annotated with SnpEff. For population genomic analysis, PCA and admixture modeling assessed genetic structure, while Neighbor-Joining trees, LD decay, nucleotide diversity (π), and FST evaluated phylogenetic relationships and genetic variation. Selective sweeps were detected using RAiSD, and gene-set enrichment and protein–protein interaction analyses were conducted to explore functional pathways related to adaptation. The study revealed 3,759,279 unique SNPs and demonstrated that Ladakhi cattle form a distinct genetic cluster with an estimated admixture of 68 % Bos indicus and 32 % Bos taurus ancestry. Key findings include rapid linkage disequilibrium decay, low inbreeding level, and the identification of selection signatures and genes associated with hypoxia response, energy metabolism, and cold adaptation. Mean nucleotide diversity (π, 0.0037) and FST values indicated moderate genetic differentiation from other breeds. The analysis highlighted selection signatures for genes like HIF1A, ENO4, ANGPT1, EPO, NOS3, MAPK3, HMOX1, BCL2,CAMK2D, MTOR, AKT2,PIK3CB, and MAP2K1, among others, including various keratin and heat shock proteins. The interaction between genes associated with hypoxia signaling (HIF-1) and other enriched pathways such as PI3K, mTOR, NFκB, ERK, and ER stress, reveals a complex mechanism for managing hypoxic stress in Ladakhi cattle. These findings offer valuable insights for breeding programs aimed at enhancing livestock resilience in extreme environments and enhance understanding of mammalian adaptation to high-altitude conditions.

Sentinel chicken surveillance reveals previously undetected circulation of West Nile virus in the Netherlands

ABSTRACT West Nile virus (WNV) was first detected in the Netherlands in 2020, with circulation observed in birds, mosquitoes, and humans in two geographical areas. Usutu virus (USUV) has been circulating in the Netherlands since 2016. Following the detection of WNV in the Netherlands, we investigated the possible use of petting zoos as urban sentinel sites to examine the extent of WNV and USUV circulation around the two WNV outbreak locations. Chickens at petting zoos and in backyards were sampled within a 15-kilometer radius of the confirmed WNV circulation areas at three timepoints over one year (2021–2022). Sera were analysed using a protein microarray for binding antibodies to orthoflavivirus NS1 antigens and reactive samples were confirmed through micro-focus reduction neutralization tests (mFRNT). Furthermore, mosquitoes at sampling locations were collected to assess their blood feeding behaviour. This serosurvey detected the circulation of USUV and WNV in petting zoo and backyard chickens in 2021, both within and outside the 2020 outbreak areas. The WNV circulation was not detected by other existing surveillance schemes in mosquitoes, wild birds, horses and humans. In addition, the results show rapid decay of USUV antibodies in approximately 20 weeks. Our findings support the utility and the added value of petting zoo chickens as sentinels for monitoring USUV and WNV circulation compared to other available methods. Seroconversions observed in petting zoos and backyard chickens living in or near densely populated urban areas further highlighted potential public health risks that went undetected.

Identifying the β-to-α phase transition during the long cycling process in Na2FePO4F cathode

Na2FePO4F has emerged as a promising cathode for large-scale electrochemical energy storage, primarily due to its abundance of raw materials and distinctive two-dimensional ion channels. Counterintuitively, pristine Na2FePO4F lacks the long-term stability typically seen in polyanionic cathodes, which severely impedes its practical application. Traditionally, the origin of this problem has been only phenomenologically attributed to the poor intrinsic electronic conductivity and structural instability of Na2FePO4F. Here, we identify that rapid capacity fading of Na2FePO4F is closely related to the β-to-α phase transition during the long cycling process. Furthermore, we develop a practical high-entropy doping strategy and the corresponding microstructure engineering to mitigate the impact of the phase transition on the crystal structure, thereby increasing the capacity retention from 56 % to 94 % over 400 cycles at 0.5C in coin cell, and attain almost 100 % capacity retention after 300 cycles at 0.1C in pouch cell. Overall, this work unveils the mechanism of rapid capacity decay in Na2FePO4F and lays the groundwork for the rational design of durable polyanionic electrodes.

Regulatory logic and transposable element dynamics in nematode worm genomes.

Genome sequencing has revealed a tremendous diversity of transposable elements (TEs) in eukaryotes but there is little understanding of the evolutionary processes responsible for TE diversity. Non-autonomous TEs have lost the machinery necessary for transposition and rely on closely related autonomous TEs for critical proteins. We studied two mathematical models of TE regulation, one assuming that both autonomous tranposons and their non-autonomous relatives operate under the same regulatory logic, competing for transposition resources, and one assuming that autonomous TEs self-attenuate transposition while non-autonomous transposons continually increase, parasitizing their autonomous relatives. We implemented these models in stochastic simulations and studied how TE regulatory relationships influence transposons and populations. We found that only outcrossing populations evolving with Parasitic TE regulation resulted in stable maintenance of TEs. We tested our model predictions in Caenorhabditis genomes by annotating TEs in two focal families, autonomous LINEs and their non-autonomous SINE relatives and the DNA transposon Mutator . We found broad variation in autonomous - non-autonomous relationships and rapid mutational decay in the sequences that allow non-autonomous TEs to transpose. Together, our results suggest that individual TE families evolve according to disparate regulatory rules that are relevant in the early, acute stages of TE invasion.

Ionic Covalent Organic Framework Membrane as Active Separator for Highly Reversible Zinc-Sulfur Battery.

Zinc-sulfur (Zn-S) batteries exhibit a high theoretical energy density, nontoxicity, and cost-effectiveness, demonstrating significant potential for integration into large-scale energy storage systems. However, the phenomenon of polysulfide (including dissolved S8 and Sx2-) shuttling is a major issue that results in rapid capacity decay and a short lifespan, limiting the practical performance of sulfur-based batteries. Herein, we fabricated an ionic covalent organic framework (iCOF) membrane as an active separator for the Zn-S battery. Sulfonic acid groups were introduced to the COF membrane, providing abundant negative charge sites in its pore wall. By combining size sieving and charge interaction between the polysulfide and pore wall, the iCOF membrane inhibited the crossover of polysulfides to the Zn metal anode without affecting the transport of metal ions. The Zn-S battery with the iCOF membrane as the separator shows a high-performance and low attenuation rate of 0.05% per cycle over 300 cycles at 2.5 A g-1. This study emphasizes the significance of separator design in enhancing Zn-S batteries and showcases the potential of functionalized framework materials for the development of high-performance energy storage systems.

Towards an information-based theory of structure.

We call for a theory of the particle-scale structure of materials that is based on the general notion of information rather than its special case of symmetry. An inherent limitation to the symmetry-based understanding of structure is described. The rapid decay in interaction strength with interparticle distance is used to argue for the representability of a system locally through the neighbourhoods of its constituent particles. The extracopularity coefficient E is presented as a local quantifier of information and compared to point group order |G|, a local quantifier of symmetry. The former is found to have nearly double the resolution of the latter for a set of commonly encountered coordination geometries. A proof is given for the generality of extracopularity over point symmetry. Some practical challenges and future perspectives are discussed.

Internal Conversion Cascade in a Carbon Nanobelt: A Multiconfigurational Quantum Dynamical Study.

Carbon nanobelts feature intriguing photophysical properties, due to their high symmetry and structural rigidity. Here, we consider a (6,6) armchair carbon nanobelt, i.e., the very first carbon nanobelt to be synthesized [Povie et al., Science 2017, 356, 172] and characterize the internal conversion dynamics using multiconfigurational quantum dynamics via the multi-layer multiconfiguration time-dependent Hartree (ML-MCTDH) method. A symmetry-adapted linear vibronic coupling Hamiltonian for 26 electronic states and 210 vibrational modes is employed. Electronic excitations are found to decay through a dense manifold of excited states, which interact via multiple conical intersections, while inducing minimal geometry change. It is shown that a rapid coherent decay, exhibiting a nonvanishing quantum flux on a time scale of less than 50 fs, transitions toward a slower, decoherent decay at longer times. As previously suggested in the literature, electronic relaxation is hindered by phonon bottlenecks such that a stepwise internal conversion cascade is observed. The computed vibronic absorption spectrum is shown to be in good agreement with the experimental spectrum.

An Utrastable Mg/Zr Modified P2‐Type Na2/3Ni1/3Mn2/3O2 Cathode Material for High‐Power Sodium‐Ion Batteries

AbstractP2‐Na2/3Ni1/3Mn2/3O2 demonstrates high energy density owing to its high specific capacity and high discharge voltage, but suffering from rapid performance decay due to severe structural degradation and aggravated surface side reaction during high‐voltage cycling. Herein, a Mg/Zr modified Na0.67Ni0.25Mg0.08Mn0.64Zr0.03O2 cathode is proposed with good structural stability and excellent cycling performance, showing reversible capacity of 123.2 mAh g−1 (0.1 C) and capacity retention of 99.1% after 100 cycles. The cycling stability is outstanding among P2‐type cathodes reported so far. In situ XRD analyses reveal a suppressed P2‐O2 phase transition after Mg modification, further incorporation of Zr greatly stabilizes the layered structure as some Zr ions reside in the Na layer providing a pinning effect to reduce the slide of TMO2 layer. First‐principles calculations suggest that oxygen loss in Na0.67Ni0.25Mg0.08Mn0.64Zr0.03O2 cathode is suppressed as Zr incorporation prevents the formation of oxygen vacancies. XPS analyses verify a Zr─O protective layer self‐segregated on particle surface during material synthesis. The expanded Na+ transport channel confirmed by the XRD analysis well explains the favored Na‐ion mobility verified by a high reversible capacity of 105.5 mAh/g at 20 C. This work sheds new light on providing a practical P2‐structured cathode material for high‐power sodium ion batteries.

An Alternative Model for the Orbital Decay of M82 X-2: The Anomalous Magnetic Braking of a Bp Star

Recently, the first pulsating ultraluminous X-ray source M82 X-2 was reported to be experiencing a rapid orbital decay at a rate of Ṗ=−(5.69±0.24)×10−8ss−1 based on 7 yr NuSTAR data. To account for the observed orbital-period derivative, it requires a mass transfer rate of ∼200Ṁedd ( Ṁedd is the Eddington accretion rate) from the donor star to the accreting neutron star. However, other potential models cannot be completely excluded. In this work, we propose an anomalous magnetic braking (AMB) model to interpret the detected orbital decay of M82 X-2. If the donor star is an Ap/Bp star with an anomalously strong magnetic field, the magnetic coupling between strong surface magnetic field and irradiation-driven wind from the surface of the donor star could cause an efficient angular-momentum loss, driving a rapid orbital decay observed in M82 X-2. The AMB mechanism of an Ap/Bp star with a mass of 5.0–15.0 M ⊙ and a surface magnetic field of 3000–4500 G could produce the observed Ṗ of M82 X-2. We also discuss the possibility of other alternative models including the companion star expansion and a surrounding circumbinary disk.

Electrochemical sintering of lithium metal constrained by buffer layer in anode-free all-solid-state batteries

Anode-free all-solid-state lithium-metal batteries hold promise in energy density. However, they often suffer from rapid capacity decay, and the underlying mechanisms remain unclear, especially at high current densities. Here, failure mechanism is studied systematically for garnet solid electrolyte in Li anode-free all-solid-state batteries. By combining morphology evolution analysis and quantitative assessments, the decreased Coulombic efficiency for solid electrolyte at high current densities is attributed to large amounts of lump-shaped lithium deposits via the electrochemical sintering. The lump-shaped lithium deposits encapsulate numerous voids and solid electrolyte interphase leading to irreversible capacities. Furthermore, serious pulverization of lithium deposits is observed after long cycles. An addition of polydimethylsiloxane membrane is attempted to constrain electrochemical sintering of lithium and compact lithium metal deposits, leading to prolonged cycling performance.

Unveiling the Enigma of Molar Incisor Hypomineralisation: Causes, Consequences and Management Strategies

Abstract Molar incisor hypomineralisation (MIH) is a defect in the development of tooth enamel, affecting permanent first molars and incisors. This article explores MIH causes, consequences and management strategies for dental professionals. MIH is widespread, ranging from 2.4% to 40.2% globally. South America has the highest prevalence, while Africa has the lowest. Clinically, MIH presents as demarcated white, yellow or brownish opacities on the enamel surface. Affected teeth are fragile and prone to chipping, hypersensitivity and caries. MIH disrupts the tooth’s structure, increasing the risk of fractures, dentin exposure, pulp inflammation and rapid tooth decay. It can also lead to poor oral hygiene, aesthetic concerns and reduced quality of life for children. The causes of MIH are multifactorial and involve systemic or environmental factors during pre-natal or post-natal tooth development. Potential factors include childhood illnesses, antibiotic use, environmental toxins and Vitamin D deficiency. Early diagnosis and intervention are crucial for MIH management. Treatment options depend on the severity of the condition and may involve remineralisation, desensitisation, fluoride therapy, pit and fissure sealants, restorations or extractions. MIH is a common dental concern in children. Early management by dental professionals can help prevent complications and improve oral health outcomes.

Fast diffusion and stable topotactic reaction in single crystal conversion anode

Conversion electrodes typically have high theoretical specific capacity, but mostly suffer large structural changes during charge/discharge and result in poor cycling stability. The optimization of the polycrystalline materials is the mostly used strategy, however, these polycrystalline materials are intrinsically vulnerable to grain-boundary (intergranular) fracture caused by the anisotropic volume change during sodiation/desodiation, resulting in rapid impedance growth and capacity decay. Herein, we propose an alternative pathway to design single-crystal materials as potential conversion anodes. As an example, SnO2 with different crystallinities is successfully synthesized via solvothermal methods and compared to determine the implications of different crystallinity for the electrochemical properties of conversion anodes. It is demonstrated that the single-crystal SnO2 not only has faster Na+ diffusion dynamics but also maintains structural stability via topotactic reaction. Further optimization of the electron conduction and structural robustness is realized by uniformly covering a graphitic carbon shell on the surface of single-crystal SnO2 nanosheets. The modified single-crystal SnO2 exhibits a high reversible capacity of 436.2 mA h g–1 and maintains a high capacity of 257.1 mA h g-1 and remarkable capacity retention of about 98.9% after 9000 cycles at 5000 mA g-1. The deep understandings of the topotactic reaction in single crystal conversion anode in this work provide a theoretical foundation and new direction for further developing electrode materials with excellent electrochemical performance, especially high rate capabilities, and long cyclability.

Near-Inertial Response of a Salinity-Stratified Ocean

Abstract We study the near-inertial response of the salinity-stratified north Bay of Bengal to monsoonal wind forcing using 6 years of hourly observations from four moorings. The mean annual energy input from surface winds to near-inertial mixed layer currents is 10–20 kJ m−2, occurring mainly in distinct synoptic “events” from April–September. A total of fifteen events are analyzed: Seven when the ocean is capped by a thin layer of low-salinity river water (fresh) and eight when it is not (salty). The average near-inertial energy input from winds is 40% higher in the fresh cases than in the salty cases. During the fresh events, 1) mixed layer near-inertial motions decay about two times faster and 2) near-inertial kinetic energy below the mixed layer is reduced by at least a factor of three relative to the salty cases. The near-inertial horizontal wavelength was measured for one fresh and one salty event; the fresh was about three times shorter initially. A linear model of near-inertial wave propagation tuned to these data reproduces 2); the thin (10 m) mixed layers during the fresh events excite high modes, which propagate more slowly than the low modes excited by the thicker (40 m) mixed layers in the salty events. The model does not reproduce 1); the rapid decay of the mixed layer inertial motions in the fresh events is not explained by the linear wave propagation at the resolved scales; a different and currently unknown set of processes is likely responsible.