Extinction Intensity Research Articles

Improved SERS activity of TiN microstructures by surface modification with Au

Over the years, numerous outstanding research groups around the world have been working tirelessly on metallic SERS substrates. Although these efforts have led to the development of various sensors and pushed the field forward, today this line of research seems saturated and exhausted. In this work, we address this issue by exploring an emerging topic in recent literature: the fabrication of high-performance TiN SERS-active structures. TiN thin film was sputtered onto pyramidal Si microstructures. Spectroscopic ellipsometry measurements confirmed the plasmonic properties of the TiN material above its plasma wavelength of 515 nm. The Si-TiN surface was subsequently modified with an Au layer, which was then transformed into Au nanoparticles (Au NPs) during the Rapid Thermal Annealing process. The Si-TiN-AuNPs samples exhibited the highest extinction intensity, as well as the best SERS signal intensity for the model Raman reporter molecule. Further analysis of the SERS data showed that the presence of the Au thin film only moderately increased SERS activity, while Au NPs enhanced the SERS signal by one order of magnitude. Final Si-TiN-AuNPs platforms were successfully employed for the detection of vitamin B12, demonstrating a low limit of detection (8.57•10–8 M) along with excellent point-to-point repeatability.Graphical abstract

Palladium catalyzed carbon-carbon bond formation on tunable quinolines with DFT study

The synthesis of new quinoline fluorophores was accomplished through a meticulous four-step molecular assembly utilizing Suzuki and acid-amine cross-coupling reactions. The integrity of each fluorophore was rigorously confirmed via comprehensive spectroscopic analyses, including 1H and 13C NMR, DEPT-135, H-H COSY, HSQC NMR and HRMS techniques. Subsequently, the absorbance and emission spectra of the newly synthesized fluorophores were thoroughly investigated. Notably, these fluorophores displayed impressive characteristics, with high intensity and significant molar extinction coefficients, along with Stokes shifts ranging from 0.5052 × 104 to 0.6234 × 104 in acetonitrile (ACN) solvent. Absorbance spectra were found to confine within the 320–360 nm range, while emission spectra were consistently observed within the 380–450 nm range upon excitation at 350 nm. The electronic structure of the molecules was elucidated using techniques such as Density Functional Theory (DFT) and Molecular Electrostatic Potential (MEP) mapping. Additionally, the calculated global reactivity parameters provided valuable insights. In particular, compound 8b exhibited a distinctly larger energy gap compared to other fluorophores, demonstrating its exceptional properties. The comparison between experimental and theoretical UV-Vis spectra also showcased the remarkable consistency and quality of the synthesized fluorophores, highlighting the significant potential of this work in the field of fluorophore development.

Respiratory protein-driven selectivity during the Permian-Triassic mass extinction

Extinction selectivity determines the direction of macroevolution, especially during mass extinction; however, its driving mechanisms remain poorly understood. By investigating the physiological selectivity of marine animals during the Permian-Triassic mass extinction, we found that marine clades with lower O2-carrying capacity hemerythrin proteins and those relying on O2 diffusion experienced significantly greater extinction intensity and body-size reduction than those with higher O2-carrying capacity hemoglobin or hemocyanin proteins. Our findings suggest that animals with high O2-carrying capacity obtained the necessary O2 even under hypoxia and compensated for the increased energy requirements caused by ocean acidification, which enabled their survival during the Permian-Triassic mass extinction. Thus, high O2-carrying capacity may have been crucial for the transition from the Paleozoic to the Modern Evolutionary Fauna.

Cacao Water Use, Canopy Characteristics and Yield as Affected by Irrigation and Shade in a Rainforest Zone of Nigeria

There has been need to improve crop and water productivity considering the need for agricultural intensification in the realm of increasing water scarcity and drought in several regions of the world. Information is limited about the effects of irrigation on cacao water use (evapotranspiration) especially, during the terminal drought situation of the dry season in the rainforest agroecology of Nigeria. The effects of shade and dry season irrigation was examined on tree water use, canopy characteristics and pod and bean yields of cacao (Theobroma cacao L.). Treatments were 2 by 2 factorial combinations of irrigation intervals (5 and 10 days) and shade and no-shade (open sun) laid out in a split-plot scheme with 3 replications. Shade regimes constituted the main plots and irrigation intervals the sub-plot treatments. Irrigation water was delivered at 5-and 10-day intervals on emitter lines using gravity drip system. Irrigation combinations affected cacao canopy characteristics (leaf area index) and light integrals (photosynthetic active radiation (PAR) and canopy light attenuation (extinction coefficient, k) within the cacao field. The unshaded-irrigation had higher proportion of incident radiation (I) transmitted (Io) through the canopy (IO/I), PAR intensity, and canopy extinction coefficients (k) compared with the shaded plus irrigations at 5-and 10-day intervals. Cumulative seasonal irrigation (12119 and 8483 mm), soil moisture contents (19.6 to 13.7 %) and cacao water use (ETc: 3.8 and 3.2 mm.day-1) differed for the respective 5- and 10-day irrigation intervals. The unshaded plus 5- and 10-day irrigation intervals out-yielded the shaded-irrigation combinations for number and weights of pods and beans. Pod and bean yields were significantly different under irrigation treatments, the 5-day irrigation produced greater number and heavier pods and beans compared with the 10-day irrigation. For the shade-irrigation combinations the range of values were: weights of pods (78000 to 6000 kg/plant), beans (4.8 to 3.2 t/ha) and water productivities: Irrigation WUE: 0.45 to 0.33 mm/kg/ha) and ET WUE: 0.11 to 0.09 mm/kg/ha). The shade-irrigation strategy enhanced cacao leaf area index, water use and bean yields and ameliorated climate stress.

Three-dimensional structure and transport flux of springtime smoke aerosols over the Indochina Peninsula

Springtime smoke aerosols attributable to biomass burning on the Indochina Peninsula (ICP) are a major source of absorbing aerosols globally, and play a nonnegligible perturbing role in climate change. Using smoke extinction profiles provided by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument, and aerosol and meteorological reanalyses for the period 2007–2021, this study investigated the three-dimensional structure and transport flux of springtime smoke aerosols over the ICP. Stratified analysis revealed that CALIOP-derived peaks of smoke aerosol optical depth (SAOD) and smoke mass flux (SMF) at altitudes of 0–2 km occur over the central ICP, which is the main source region. Driven by a southwesterly jet stream and updrafts, massive amounts of smoke aerosols are transported toward the northeast of the ICP, resulting in the largest stratified SAOD and SMF observed at altitudes of 2–4 km. Over the main smoke source regions, the estimated springtime SMF was approximately 0.4 Tg accumulated through a distance of 2° latitude at altitudes of 2–4 km. Meteorological analyses indicated a path for the transport of smoke aerosols to the mid-troposphere. Smoke aerosols in the source region are first lifted thermally to the 600-hPa level. Lifting then continues to the 500-hPa level via the combined effects of topography and frequent, deep, and dry convective updrafts over the mountainous areas of the northern ICP. The smoke aerosols are subsequently transported to South China and the western Pacific owing to strong westerly winds and weak vertical motion. Further analyses demonstrated that differences in meteorological conditions between daytime and nighttime have substantial impact on the vertical structure of smoke aerosols, particularly over the northeast of ICP. Compared to daytime, enhanced updrafts and moisture transport at night favor further lifting of smoke aerosols and greater extinction intensity owing to increased hygroscopic growth.

Tunable hybridized plasmons-phonons in a graphene/mica-nanofilm heterostructure.

Graphene plasmons exhibit significant potential across diverse fields, including optoelectronics, metamaterials, and biosensing. However, the exposure of all surface atoms in graphene makes it susceptible to surrounding interference, including losses stemming from charged impurity scattering, the dielectric environment, and the substrate roughness. Thus, designing a dielectric environment with a long lifetime and tunability is essential. In this study, we created a van der Waals (vdW) heterostructure with graphene nanoribbons and mica nano-films. Through Fourier-transform infrared spectroscopy, we identified hybrid modes resulting from the interaction between graphene plasmons and mica phonons. By doping and manipulating the structure of graphene, we achieved control over the phonon-plasmon ratio, thereby influencing the characteristics of these modes. Phonon-dominated modes exhibited stable resonant frequencies, whereas plasmon-dominated modes demonstrated continuous tuning from 1140 to 1360 cm-1 in resonance frequency, accompanied by an increase in extinction intensity from 0.1% to 1.2%. Multiple phonon couplings limited frequency modulation, yielding stable resonances unaffected by the gate voltage. Mica substrates offer atomic level flatness, long phonon lifetimes, and dielectric functionality, enabling hybrid modes with high confinement, extended lifetimes (up to 1.9 picoseconds), and a broad frequency range (from 750 cm-1 to 1450 cm-1). These properties make our graphene and mica heterostructure promising for applications in chemical sensing and integrated photonic devices.

Age-dependent extinction and the neutral theory of biodiversity.

Red Queen (RQ) theory states that adaptation does not protect species from extinction because their competitors are continually adapting alongside them. RQ was founded on the apparent independence of extinction risk and fossil taxon age, but analytical developments have since demonstrated that age-dependent extinction is widespread, usually most intense among young species. Here, we develop ecological neutral theory as a general framework for modeling fossil species survivorship under incomplete sampling. We show that it provides an excellent fit to a high-resolution dataset of species durations for Paleozoic zooplankton and more broadly can account for age-dependent extinction seen throughout the fossil record. Unlike widely used alternative models, the neutral model has parameters with biological meaning, thereby generating testable hypotheses on changes in ancient ecosystems. The success of this approach suggests reinterpretations of mass extinctions and of scaling in eco-evolutionary systems. Intense extinction among young species does not necessarily refute RQ or require a special explanation but can instead be parsimoniously explained by neutral dynamics operating across species regardless of age.

Scaling laws in the evolutionary processes of marine animals over the last 540 million years

Scaling laws are ubiquitous in modern biological systems. However, whether such patterns existed in deep-time biological systems is less investigated; the best-known example is the scaling law between the frequency and size of extinction events. Here, I show that the variation rates of biodiversity, origination intensity, extinction intensity, and body size of marine animals during the last 540 million years exhibited scaling laws. I then derive a general form of these scaling laws from a conceptual model with some principles of thermodynamics and assumptions about the global biological system. The results in this study suggest that the scaling laws systematically appearing in the biological metrics characterizing different aspects of the evolutionary processes of marine animals likely belong to the same universality class and probably derived from a set of common factors.

A wavelet analysis method to retrieve thermal conductivity and radiative properties of intense extinction and low conductive medium

The accurate acquisition of the physical properties of strongly extinction materials limits their application development. In order to solve the problem of large errors in the high temperature measurement of these materials, this paper constructs an inversion model for the radiative and conductive coupled heat transfer through wavelet decomposition coefficients, and compares it with traditional methods. The radiative and conductive coupled heat transfer model is solved by finite volume method and Monte Carlo method. Daubechies nine wavelet is used for signal wavelet analysis. It has been discovered that the wavelet decomposition parameters of the temperature field are mainly concentrated in the 4–8 wavelet frequency band of wavelet, it can separate from the random error that is mainly concentrated in the 1–3 frequency band of wavelet. Most of physical properties like the heating power, convective heat transfer coefficient, material thermal conductivity, extinction coefficient has a great impact on the waveform and amplitude of wavelet detail coefficient and approximation coefficient, and the change trend of approximation coefficient and detail coefficient amplitude is consistent with the trend of temperature field. However, the effect of scattering albedo on wavelet parameters is tiny. Through inversion, it is found that the inversion model based on wavelet decomposition parameters of 5–7 frequency band has higher accuracy when random error exists.

Hydrogen-Induced Aggregation of Au@Pd Nanoparticles for Eye-Readable Plasmonic Hydrogen Sensors.

Plasmonic materials provide a promising platform for optical hydrogen detection, but their sensitivities remain limited. Herein, a new type of eye-readable H2 sensor based on Au@Pd core-shell nanoparticle arrays (NAs) is reported. After exposed to 2% H2, Au@Pd (16/2) NAs demonstrate a dramatic decrease in the optical extinction intensity, along with an obvious color change from turquoise to gray. Experimental results and theoretical calculations prove that the huge optical change resulted from the H2-induced aggregation of Au@Pd nanoparticles (NPs), which remarkably alters the plasmon coupling effect between NPs. Moreover, we optimize the sensing behavior from two aspects. The first is selecting appropriate substrates (either rigid glass substrate or flexible polyethylene terephthalate substrate) to offer moderate adhesion force to NAs, ensuring an efficient aggregation of Au@Pd NPs upon H2 exposure. The second is adjusting the Pd shell thickness to control the extent of NP aggregation and thus the detection range of the as-prepared sensors. This work highlights the advantage of designing eye-readable plasmonic H2 sensors from the aspect of tuning the interparticle plasmonic coupling in NP assemblies. Au@Pd NAs presented here have several advantages in terms of simple fabrication method, eye-readability in air background at room temperature, tunable detection range, and high cost-effectiveness.

Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy Agent

Although plasmonic palladium (Pd) nanospheres are thermodynamically stable and have high photothermal conversion due to the free and bound electron coupling associated with the intrinsic high interband transition, they have not attracted attention as a photothermal conversion material for next-generation photothermal cancer therapy. This is because the Pd nanospheres generate the localized surface plasmon resonance (LSPR) intrinsically in the ultraviolet region, which is far away from the biological transparent window (750–900 nm). In this study, we controlled the LSP wavelength of Pd nanospheres by coating with high refractive index TiO2 shells taking advantage of the Pd LSPR which is highly sensitive to changes in the local refractive index around the nanospheres. Our calculations indicated that the absorption cross section at 808 nm (corresponding to the wavelength used for photothermal treatment) was increased by 4.5 times by redshifting the LSPR and increasing the extinction intensity associated with the coating with TiO2 shell. Experiments confirmed the theoretical prediction in that the LSPR of the synthesized Pd nanospheres with a diameter of 81 nm was significantly redshifted by coating with amorphous TiO2 shell, resulting in significant large extinction intensity at 808 nm. The photothermal conversion efficiency was estimated to be 50%. In vitro cell tests, HeLa cells incubated with 100–300 μg/mL TiO2-coated Pd nanospheres were efficiently killed by irradiating 808 nm laser (1.8 W) even though the nanospheres with the same concentrations showed little cytotoxicity. These results indicate that the Pd nanospheres coated with high refractive index shells can be promising as a photothermal therapy agent.

Collective Resonances of a Twisted Plasmonic Array Pair

Plasmonic SLR (surface lattice resonance) has sharp and intense extinction or absorption peaks, which facilitates a variety of optical and spectral applications, e.g., optical filters, absorbers, reflectors, sensors, etc. In this work, we propose a plasmonic array pair structure composed of two stacked finite square array panels. By twisting it, its plasmonic SLR changes, since the break of periodicity alters the inter-layer plasmonic coupling. Numerical simulation is carried out using the DDA (discrete dipole approximation) method. Simulation results show that its optical properties such as extinction spectra/absorption spectra change dramatically when the two-layer structure is twisted by only a small angle. More interestingly, two resonance peaks at different wavelengths show an inverse trend while twisting, one gets lower and broader, while the other gets higher and narrower. Dipole mapping of amplitude and phase is checked to reveal the plasmonic coupling under twist. The influence of environment/material permittivity on spectra is also examined. Results introduced in this work may work as a scientific tool to reveal more properties of plasmonic SLR and can serve as an angle sensor, tunable optical filter, chiral sensor, etc.

Decreasing Phanerozoic extinction intensity as a consequence of Earth surface oxygenation and metazoan ecophysiology

The decline in background extinction rates of marine animals through geologic time is an established but unexplained feature of the Phanerozoic fossil record. There is also growing consensus that the ocean and atmosphere did not become oxygenated to near-modern levels until the mid-Paleozoic, coinciding with the onset of generally lower extinction rates. Physiological theory provides us with a possible causal link between these two observations-predicting that the synergistic impacts of oxygen and temperature on aerobic respiration would have made marine animals more vulnerable to ocean warming events during periods of limited surface oxygenation. Here, we evaluate the hypothesis that changes in surface oxygenation exerted a first-order control on extinction rates through the Phanerozoic using a combined Earth system and ecophysiological modeling approach. We find that although continental configuration, the efficiency of the biological carbon pump in the ocean, and initial climate state all impact the magnitude of modeled biodiversity loss across simulated warming events, atmospheric oxygen is the dominant predictor of extinction vulnerability, with metabolic habitat viability and global ecophysiotype extinction exhibiting inflection points around 40% of present atmospheric oxygen. Given this is the broad upper limit for estimates of early Paleozoic oxygen levels, our results are consistent with the relative frequency of high-magnitude extinction events (particularly those not included in the canonical big five mass extinctions) early in the Phanerozoic being a direct consequence of limited early Paleozoic oxygenation and temperature-dependent hypoxia responses.

Constructing a Facile Biocomputing Platform Based on Smart Supramolecular Hydrogel Film Electrodes with Immobilized Enzymes and Gold Nanoclusters.

Herein, fluorescent gold nanoclusters (AuNCs) and horseradish peroxidase (HRP) were simultaneously embedded into self-assembled dipeptide supramolecular films of N-fluorenylmethoxycarbonyl diphenylalanine (Fmoc-FF) on the surface of ITO electrodes (Fmoc-FF/AuNCs/HRP) by using a simple single-step process. In the films, both the fluorescence property of AuNCs and the bioelectrocatalytic property of HRP were well maintained and could be reversibly regulated by pH-sensitive structural changes in the Fmoc-FF hydrogel films. Cu(II)/EDTA in the solution could lead to the aggregation/disaggregation of AuNCs and further quenching/dequenching the fluorescence signal from the films. Meanwhile, the blue complexes formed by Cu(II) and EDTA could produce a UV-vis signal in the solution. In addition, the coordinated Cu(II) in the films enhanced the electrocatalytic capacity toward the reduction of H2O2 and could switch the current signal. A biomolecular logic circuit was built based on the smart film electrode system by using pH, the concentrations of EDTA, Cu(II) and H2O2 as inputs, while the fluorescence intensity (FL), current (I) and UV-vis extinction (E) of the solution as outputs. Various logic devices were fabricated using the uniform platform, consisting of an encoder/decoder, demultiplexer, dual-transfer gate, keypad lock, digital comparator, half adder, and controlled NOT (CNOT) gate. Specifically, an electronic three-value logic gate, gullibility (ANY) gate, was first mimicked in this biocomputing system. This work not only demonstrated the construction of a new type of multivalued logic gate by using a dipeptide micromolecular matrix but also provided a new approach for designing sophisticated biologic functions, establishing smart multianalyte biosensing or fabricating biology information processing through the use of a simple film system.

Color Changes in Ag Nanoparticle Aggregates Placed in Various Environments: Their Application to Air Monitoring.

Fresh Ag nanoparticles (NPs) dispersed on a transparent SiO2 exhibit an intense optical extinction band originating in localized surface plasmon resonance (LSPR) in the visible range. The intensity of the LSPR band weakened when the Ag NPs was stored in ambient air for two weeks. The rate of the weakening and the LSPR wavelength shift, corresponding to visual chromatic changes, strongly depended on the environment in which Ag NPs were set. The origin of a chromatic change was discussed along with both compositional and morphological changes. In one case, bluish coloring followed by a prompt discoloring was observed for Ag NPs placed near the ventilation fan in our laboratory, resulted from adsorption of large amounts of S and Cl on Ag NP surfaces as well as particle coarsening. Such color changes deduce the presence of significant amounts of S and Cl in the environment. In another case, a remarkable blue-shift of the LSPR band was observed for the Ag NPs stored in the desiccator made of stainless steel, originated in the formation of CN and/or HCN compounds and surface roughening. Their color changed from maroon to reddish, suggesting that such molecules were present inside the desiccator.

Palladium-rich plasmonic nanorattles with enhanced LSPRs via successive galvanic replacement mediated by co-reduction.

Catalytic transformations under light irradiation have been extensively demonstrated by the excitation of the localized surface plasmon resonances (LSPRs) in noble metal-based nanoparticles. To fully harness the potential of noble metal-based nanocatalysts, it is fundamentally imperative to explore hybrid nano-systems with the most desirable enhanced LSPRs and intrinsic catalytic activities. Pd-containing hollow multimetallic nanostructures transformed from the sacrificial template of Ag via galvanic replacement reaction (GRR) offer such ideal platforms to gain quantitative insights into nanoparticle-catalyzed reactions. In this work, we successfully fabricated Pd-rich plasmonic nanorattles by means of co-reduction mediated GRR using CTAC-stabilized Au@Ag nanocuboids as templates and H2PdCl4 as a Pd precursor in the presence of ascorbic acid (AA) acting as a mild reducing agent. Successive titration of Au@Ag nanocuboids with the Pd precursor in the presence of AA modulates the rate of the galvanic replacement reaction as well as effective diffusion of Pd into the Ag matrix, resulting in increased dimensions and enlarged cavity sizes. Reduction of oxidized Ag+ back to Ag0 by AA, along with the deposition of Pd to form homogeneously mixed bimetallic layers not only prevents LSPRs peak from damping with increasing Pd content but also ensures the enhanced catalytic activities. Through precise control of added H2PdCl4 titrant, an unconventional steep increase in extinction intensity accompanied by tunable plasmon resonances shifted towards the NIR spectral region was experimentally observed due to the increasing physical cross-sections and plasmon hybridization in hollow nanorattles. Four colloids of Pd-rich nanorattles obtained by addition of different amounts of the H2PdCl4 titrant were used as catalysts for reduction of 4-nitrothiophenol in the presence of NaBH4 monitored by SERS.

Regime Shifts in an Early Triassic Subtropical Ecosystem

The Early Triassic was one of the most remarkable time intervals in Earth History. To begin with, life on Earth had to face one of the largest subaerial volcanic degassing, the Siberian Traps, followed by a plethora of accompanying environmental hazards with pronounced and repeated climatic changes. These changes not only led to repeated and, for several marine nektonic clades, intense extinction events but also to significant changes in terrestrial ecosystems. The Early Triassic terrestrial ecosystems of the southern subtropical region (Pakistan) are not necessarily marked by abrupt extinction events but by extreme shifts in composition. Modern ecological theories describe such shifts as catastrophic regime shifts. Here, the applicability of modern ecological theories to these past events is tested. Abrupt shifts in ecosystems can occur when protracted changing abiotic drivers (e.g. climate) reach critical points (thresholds or tipping points) sometimes accentuated by stochastic events. Early Triassic terrestrial plant ecosystem changes stand out from the longer term paleobotanical records because changes of similar magnitude have not been observed for many millions of years before and after the Early Triassic. To date, these changes have been attributed to repeated severe environmental perturbations, but here an alternative explanation is tested: the initial environmental perturbations around the Permian–Triassic boundary interval are regarded here as a main cause for a massive loss in terrestrial ecosystem resilience with the effect that comparatively small-scale perturbations in the following ∼5 Ma lead to abrupt regime shifts in terrestrial ecosystems.

A gold nanodot array imprinting process based on solid-state dewetting for efficient oxide-free photovoltaic devices

We report the development of an efficient imprinting process for the formation of metal (Au) nanodot arrays using a square-patterned medium substrate. Solid-state dewetting is induced by differences in the surface energy of the metal film and the interface energy between the substrate and the metal film. Thus, uniform metal nanodot arrays were transferred to the desired substrate by controlling the interfacial surface free energy between the metal film and the substrate. Optical extinction measurements showed an intense extinction peak at 550 nm, corresponding to the simulated result. Imprinting of the Au-nanodot arrays on the substrate enhanced the light trapping function and supported the electrical properties of a polymer electrode. In addition, the combination of a transparent conducting oxide-free device with the Au-nanodot arrays and a polymer electrode resulted in enhanced performance. This can be attributed to the fact that the Au-nanodot arrays allowed higher charge extraction, as confirmed by electrical analyses. Finally, a next-generation approach of imprinting metal nanodot arrays was introduced through the controlled solid-state dewetting mechanism in a specific area, which can be applicable not only in the development of optoelectronic devices but also in semiconductor processes requiring metal nanostructures.

High Preservation Potential of Paleogeographic Range Size Distributions in Deep Time.

AbstractReconstructing geographic range sizes from fossil data is a crucial tool in paleoecology, elucidating macroecological and macroevolutionary processes. Studies examining links between range size and extinction risk may also offer a predictive tool for identifying species most vulnerable in the "sixth mass extinction." However, the extent to which paleogeographic ranges can be recorded reliably in the fossil record is unknown. We perform simulation-based extinction experiments to examine (1) the fidelity of paleogeographic range size preservation in deep time, (2) the relative performance of different methods for reconstructing range size, and (3) the reliability of detecting patterns of extinction "selectivity" on range size. Our results suggest both that relative paleogeographic range size can be consistently reconstructed and that selectivity patterns on range size can be preserved under many extinction intensities, even when sedimentary rocks are scarce. By identifying patterns of selectivity across Earth's history, paleontologists can thus augment neontological work that aims to predict and prevent extinctions of living species. Last, we find that introducing "false extinctions" in the fossil record can produce spurious range-selectivity signals. Errors in the temporal ranges of species may pose a larger barrier to reconstructing range size-extinction risk signals than the spatial distribution of fossiliferous sediments.

Estimating survival probability using the terrestrial extinction history for the search for extraterrestrial life

Several exoplanets have been discovered to date, and the next step is the search for extraterrestrial life. However, it is difficult to estimate the number of life-bearing exoplanets because our only template is based on life on Earth. In this paper, a new approach is introduced to estimate the probability that life on Earth has survived from birth to the present based on its terrestrial extinction history. A histogram of the extinction intensity during the Phanerozoic Eon is modeled effectively with a log-normal function, supporting the idea that terrestrial extinction is a random multiplicative process. Assuming that the fitted function is a probability density function of extinction intensity per unit time, the estimated survival probability of life on Earth is sim0.15 from the beginning of life to the present. This value can be a constraint on f_i in the Drake equation, which contributes to estimating the number of life-bearing exoplanets.