We describe a new algorithm for robust principal component analysis (PCA) of electromagnetic (EM) array data, extending previously developed multivariate methods to include arrays with large data gaps, and only partial overlap between site occupations. Our approach is based on a criss-cross regression scheme in which polarization parameters and spatial...
Low-angle normal faulting is widely discussed as a possible mechanism for continental extension, however, unambiguous evidence for seismogenic low-angle normal faulting is lacking. Here, we investigate seismicity along a short segment of the Pumqu-Xianza Rift (PXR) in southern Tibet, where the HiCLIMB seismic array recorded over 500 earthquakes between 2004...
We describe novel hybrid algorithms for inversion of electromagnetic geophysical data, combining the computational and storage efficiency of a conjugate gradient approach with an Occam scheme for regularization and step-length control. The basic algorithm is based on the observation that iterative solution of the symmetric (Gauss-Newton) normal equations with conjugate...
Organisms use a variety of environmental cues to orient their movements in three-dimensional space. Here, we show that the upward movement of young Chinook salmon (Oncorhynchus tshawytscha) emerging from gravel nests is influenced by the geomagnetic field. Fish in the ambient geomagnetic field travelled farther upwards through substrate than did...
The influence of the flood pulse on fish populations has been posited, but infrequently tested or quantified. Here, we tested the effect of habitat on population size, using Prochilodus nigricans as a case study species. Floodplain habitat was based on the littoral zone area occupied by P. nigricans to feed....
Some eyespots are thought to deflect attack away from the vulnerable body, yet there is limited empirical evidence for this function and its adaptive advantage. Here, we demonstrate the conspicuous ventral hindwing eyespots found on Bicyclus anynana butterflies protect against invertebrate predators, specifically praying mantids. Wet season (WS) butterflies with...
The inaccessibility of open ocean habitat and the cryptic nature of small animals are fundamental problems when assessing the distribution of oceanic-stage sea turtles and other marine animals sharing similar life-history traits. Most methods that estimate patterns of abundance cannot be applied in situations that are extremely data limited. Here,...
We used simulated magnetic displacements to test orientation preferences of juvenile steelhead trout (Oncorhynchus mykiss) exposed to magnetic fields existing at the northernmost and southernmost boundaries of their oceanic range. Fish reared in natural magnetic conditions distinguished between these two fields by orienting in opposite directions, with headings that would...
To better understand the role of tensegrity structures in biological systems and their application to robotics, the Dynamic Tensegrity Robotics Lab at NASA Ames Research Center, Moffett Field, CA, USA, has developed and validated two software environments for the analysis, simulation and design of tensegrity robots. These tools, along with...
A wide variety of organisms show morphologically plastic responses to environmental
stressors but in general these changes are not reversible. Though less common, reversible
morphological structures are shown by a range of species in response to changes in predators,
competitors, or food. Theoretical analysis indicates that reversible plasticity increases fitness...
For decades, the bio-duck sound has been recorded in the Southern Ocean,
but the animal producing it has remained a mystery. Heard mainly during
austral winter in the Southern Ocean, this ubiquitous sound has been
recorded in Antarctic waters and contemporaneously off the Australian
west coast. Here, we present conclusive...
Few studies to date have demonstrated widespread biological impacts of ocean
acidification (OA) under conditions currently found in the natural environment.
From a combined survey of physical and chemical water properties
and biological sampling along the Washington–Oregon–California coast in
August 2011, we show that large portions of the shelf waters...
North Atlantic right whales (Eubalaena glacialis) were found in an important nineteenth century whaling area east of southern Greenland, from which they were once thought to have been extirpated. In 2007–2008, a 1-year passive acoustic survey was conducted at five sites in and near the ‘Cape Farewell Ground’, the former...
A critical seasonal event for anadromous Chinook salmon (Oncorhynchus tshawytscha) is the time at which adults migrate from the ocean to breed in freshwater. We investigated whether allelic variation at the circadian rhythm genes, OtsClock1a and OtsClock1b, underlies genetic control of migration timing among 42 populations in North America. We...
Mucous-mesh grazers (pelagic tunicates and thecosome pteropods) are common in oceanic waters and efficiently capture, consume and repackage particles many orders of magnitude smaller than themselves. They feed using an adhesive mucous mesh to capture prey particles from ambient seawater. Historically, their grazing process has been characterized as non-selective, depending...
Density-independent and density-dependent variables both affect the spatial distributions of species. However, their effects are often separately addressed using different analytical techniques. We apply a spatially explicit regression framework that incorporates localized, interactive and threshold effects of both density-independent (water temperature) and density-dependent (population abundance) variables, to study the spatial...
Fluxes of sulphur dioxide to wheat were measured over two growing seasons. The deposition velocity, vg, depended primarily on affinities of surfaces for SO2 and varied from less than 0.1 to about 1.5cms−1. Stomata were an important sink, and diurnal changes in stomatal resistance accounted for most of the variation...
The dipyridophenazine (dppz) based ruthenium polypyridyl complexes are known as molecular ‘light-switches’ for DNA. This property is poised to serve in diagnostic and therapeutic applications, but the poor cellular uptake restricts their use in live cells. Herein, we show that the cellular uptake, and more interestingly and surprisingly, the nuclear...
Highly migratory marine species can travel long distances and across entire ocean basins to reach foraging and breeding grounds, yet gaps persist in our knowledge of oceanic dispersal and habitat use. This is especially true for sea turtles, whose complex life history and lengthy pelagic stage present unique conservation challenges....
Air-breathing marine animals face a complex set of physical challenges associated with diving that affect the decisions of how to optimize feeding. Baleen whales (Mysticeti) have evolved bulk-filter feeding mechanisms to efficiently feed on dense prey patches. Baleen whales are central place foragers where oxygen at the surface represents the...
Accurate estimation of historical abundance provides an essential baseline for judging the recovery of the great whales. This is particularly challenging for whales hunted prior to twentieth century modern whaling, as population-level catch records are often incomplete. Assessments of whale recovery using pre-modern exploitation indices are therefore rare, despite the...
Leafcutter ants cut trimmings from plants, carry them to their underground nests and cut them into smaller pieces before inoculating them with a fungus that serves as a primary food source for the colony. Cutting is energetically costly, so the amount of cutting is important in understanding foraging energetics. Estimates...
Sporosarcina pasteurii is known to produce calcite or biocement in the presence of urea and Ca²⁺. Herein, we report the use of novel ultramicrosensors such as pH, Ca²⁺, and redox sensors, along with a scanning electrochemical microscope (SECM), to monitor a real-time, bacteria-mediated urea hydrolysis process and subsequent changes in...
Nanotechnology is of increasing significance. Curation of nanomaterial data into electronic databases offers opportunities to better understand and predict nanomaterials’ behaviour. This supports innovation in, and regulation of, nanotechnology. It is commonly understood that curated data need to be sufficiently complete and of sufficient quality to serve their intended purpose....
Previous studies have reported that the metastable vaterite phase of calcium carbonate can be stabilized in solution by acidic additives. Here we demonstrate that vaterite can also be stabilized directly at surfaces by engineered peptides. Our data show that the mineralisation occurs in a 'self-templating' process where calcium ions restructure...
Linking marine epizootics to a specific aetiology is notoriously difficult. Recent diagnostic successes show that marine disease diagnosis requires both modern, cutting-edge technology (e.g. metagenomics, quantitative realtime PCR) and more classic methods (e.g. transect surveys, histopathology and cell culture). Here, we discuss how this combination of traditional and modern approaches...
NMR spectroscopy is the go-to technique for determining the solution structures of organic, organometallic, and even macromolecular species. However, structure determination of nanoscale aqueous inorganic clusters by NMR spectroscopy remains an unexplored territory. The few hydroxobridged inorganic species well characterized by ¹H Nuclear Magnetic Resonance spectroscopy (¹H-NMR) do not provide...
Low-frequency vibrations are foundational for material properties including thermal conductivity and chemical reactivity. To resolve the intrinsic molecular conformational dynamics in condensed phase, we implement time-resolved third-harmonic generation (TRTHG) spectroscopy to unravel collective skeletal motions in calcite, water, and aqueous salt solution in situ. The lifetime of three Raman-active modes...
Western North Pacific gray whales (WGWs), once considered extinct, are critically endangered with unknown migratory routes and reproductive areas. We attached satellite-monitored tags to seven WGWs on their primary feeding ground off Sakhalin Island, Russia, three of which subsequently migrated to regions occupied by non-endangered eastern gray whales (EGWs). A...
A low-voltage plateau at ∼0.3 V is discovered during the deep sodiation of Na₃V₂(PO₄)₃ by combined computational and experimental studies. This new low-voltage plateau doubles the sodiation capacity of Na₃V₂(PO₄)₃, thus turning it into a promising anode for Na-ion batteries.
The ubiquity and importance of parasite co-infections in populations of free-living animals is beginning to be recognized, but few studies have demonstrated differential fitness effects of single infection versus co-infection in free-living populations. We investigated interactions between the emerging bacterial disease bovine tuberculosis (BTB) and the previously existing viral disease...
The metal organic framework, MOF-74(Ni), was synthesized in a continuous flow microwave-assisted reactor obtaining a high space-time yield (~90 g h⁻¹ L⁻¹) and 96.5% conversion of reagents. Separation of the nucleation and growth steps was performed by using uniform and rapid microwave heating to induce nucleation, which allowed a substantial...
The study of the effects of diethyldithiocarbamate (DEDTC) in some diseases is in focus for many years. However, DEDTC is a metal chelator that can present neurotoxicity as side effects. Here we investigate the effect of DEDTC on brain Zinc (Zn) content and behavior. To address this issue we used...
Combined plasmonic nanocrystals and metal–organic framework thin-films are fabricated for sensing gases in the near-infrared range. This nanocomposite thin-film shows a highly sensitive response in near-infrared absorption, which is attributed to preconcentration of gas molecules in metal–organic framework pores causing close proximity to the electromagnetic fields at the plasmonic nanocrystal...
A series of combined measurements was made at the Naval Air Station North Island (NASNI) Installation Restoration Site 5, Unit 2 during July and August 2013. Combined measurements included CO₂ respiration rate, CO₂ radiocarbon content to estimate chlorinated hydrocarbon (CH) mineralization and a zone of influence (ZOI) model. CO₂ was...
The regiodivergent O- to C- or N-carboxyl transfer of pyrazolyl carbonates is described, with DMAP giving preferential N-carboxylation and triazolinylidenes promoting selective C-carboxylation (both with up to >99 : 1 regioselectivity). An enantioselective O- to C-carboxyl variant using NHC catalysis is demonstrated (up to 92% ee), while mechanistic and DFT studies outline...
Small-angle X-ray scattering (SAXS) studies of aqueous [Ta₆O₁₉]⁸⁻
compared to prior studies of aqueous [Nb₆O₁₉]⁸⁻ reveals key
differences in behaviour, which is likely at the root of the difficultly
in developing polyoxotantalate chemistry. Specifically, where
contact ion-pairing dominates between [Nb₆O₁₉]⁸⁻ and its
counterions, solvent-separated ion-pairing between [Ta₆O₁₉]⁸⁻
and its counterions...
Climate-driven changes in biotic interactions can profoundly alter ecological communities, particularly when they impact foundation species. In marine systems, changes in herbivory and the consequent loss of dominant habitat forming species can result in dramatic community phase shifts, such as from coral to macroalgal dominance when tropical fish herbivory decreases,...
A novel method of copper indium diselenide nanoparticle
(CuInSe₂ NP) synthesis using a two-step, continuous flow,
solar microreactor is reported here. This method allows for
exceedingly fast heating and short reaction times using only
radiative heat transfer from simulated, concentrated solar
radiation. Chalcopyrite and sphalerite CuInSe₂ phases have
both been...
This study describes the combined experimental and computational elucidation of the mechanism and
origins of stereoselectivities in the NHC-catalyzed dynamic kinetic resolution (DKR) of α-substituted-β-ketoesters. Density functional theory computations reveal that the NHC-catalyzed DKR proceeds by two
mechanisms, depending on the stereochemistry around the forming bond: 1) a concerted, asynchronous...
We demonstrate a novel synthetic route to fabricate a one-dimensional
peapod-like Sb@C structure with disperse Sb
submicron-particles encapsulated in carbon submicron-tubes.
The synthetic route may well serve as a general methodology
for fabricating carbon/metallic fine structures by thermally
reducing their carbon-coated metal oxide composites.
Restricted rotations of chemical bonds can lead to the presence of persistent conformational chirality in molecules 10 lacking stereocenters. We report the development of first-ofa- kind predictive rules that enable identification of conformational chirality and prediction of racemization barriers in the diarylether heptanoid (DAEH) natural products that do not possess...
Disease dilution (reduced disease prevalence with increasing biodiversity) has been described for
many different pathogens. Although the mechanisms causing this phenomenon remain unclear,
the disassembly of communities to predictable subsets of species, which can be caused by
changing climate, land use, or invasive species, underlie one important hypothesis. In this...
The reaction conditions for the synthesis of Cu-BTC (BTC = benzene-1,3,5-tricarboxylic acid) were elucidated using a continuous-flow microreactor-assisted solvothermal system to achieve crystal size and phase control. A high-rate synthesis of Cu-BTC metal-organic frameworks with BET surface area of more than 1600 m²/g (Langmuir surface area of more than 2000...
Sexual conflict over mating can result in sex specific morphologies and behaviors that
allow each sex to exert control over the outcome of reproduction. Genital traits, in
particular, are often directly involved in conflict interactions. Via genital manipulation,
we experimentally investigated whether genital traits in red-sided garter snakes influence
copulation...
Despite the considerable advances of deposition technologies, it remains a significant challenge to form conformal deposition on surface of nanoporous carbons. Here, we introduce a new ambient hydrolysis deposition method that employs and controls pre-adsorbed water vapor on nanoporous carbons to define the deposition of TiO₂. We converted the deposited...
TAML activators promise a novel water treatment approach
by efficiently catalysing peroxide-based degradation of
chemicals of high concern at environmental concentrations.
Green design ethics demands an exploration of TAML
toxicity. Exposure to high concentrations of certain activators
caused adverse effects in zebrafish. At typical TAML
operational concentrations, development was not...
We, for the first time, employ magnesiothermic reaction to convert microwave-irradiated graphite oxide to pure graphene. The magnesiothermic reaction raises the carbon to oxygen atomic ratio from 22.2 to 165.7 and maintains a high surface area. The new strategy demonstrates an efficient method for obtaining highly pure graphene materials.
This manuscript describes the role of non-classical hydrogen bonds (NCHBs), specifically C–H···O interactions, in modern synthetic organic transformations. Our goal is to point out the seminal examples where C–H···O interactions have been invoked as a key stereocontrolling element and to provide predictive value in recognizing future and/or potential C–H···O interactions...
A field campaign, the Slope Experiment near La Fouly (SELF-2010), was conducted to monitor the evening transition of slope flows on clear-sky days from July to September 2010 in a narrow valley of the Swiss Alps. A steep west-facing slope with inclinations ranging from 25° to 45° was instrumented from...