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A single-crystal diamond X-ray pixel detector with embedded graphitic electrodes

The first experimental results from a new transmissive diagnostic instrument for synchrotron X-ray beamlines are presented. The instrument utilizes a single-crystal chemical-vapour-deposition diamond plate as the detector material, with graphitic wires embedded within the bulk diamond acting as electrodes. The resulting instrument is an all-carbon transmissive X-ray imaging detector. Within the instrument's transmissive aperture there is no surface metallization that could absorb X-rays, and no surface structures that could be damaged by exposure to synchrotron X-ray beams. The graphitic electrodes are fabricated in situ within the bulk diamond using a laser-writing technique. Two separate arrays of parallel graphitic wires are fabricated, running parallel to the diamond surface and perpendicular to each other, at two different depths within the diamond. One array of wires has a modulated bias voltage applied; the perpendicular array is a series of readout electrodes. X-rays passing through the detector generate charge carriers within the bulk diamond through photoionization, and these charge carriers travel to the nearest readout electrode under the influence of the modulated electrical bias. Each of the crossing points between perpendicular wires acts as an individual pixel. The simultaneous read-out of all pixels is achieved using a lock-in technique. The parallel wires within each array are separated by 50 µm, determining the pixel pitch. Readout is obtained at 100 Hz, and the resolution of the X-ray beam position measurement is 600 nm for a 180 µm size beam.




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Focusing with saw-tooth refractive lenses at a high-energy X-ray beamline

The Advanced Photon Source 1-ID beamline, operating in the 40–140 keV X-ray energy range, has successfully employed continuously tunable saw-tooth refractive lenses to routinely deliver beams focused in both one and two dimensions to experiments for over 15 years. The practical experience of implementing such lenses, made of silicon and aluminium, is presented, including their properties, control, alignment, and diagnostic methods, achieving ∼1 µm focusing (vertically). Ongoing development and prospects towards submicrometre focusing at these high energies are also mentioned.




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Comprehensive characterization of TSV etching performance with phase-contrast X-ray microtomography

A complete method of comprehensive and quantitative evaluation of through-silicon via reliability using a highly sensitive phase-contrast X-ray microtomography was established. Quantitative characterizations include 3D local morphology and overall consistency of statistics.




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Hard X-ray phase-contrast-enhanced micro-CT for quantifying interfaces within brittle dense root-filling-restored human teeth

Phase-contrast enhanced micro-computed tomography reveals huge discontinuities at the interfaces between dental fillings and the tooth substrate. Despite the complex micromorphology, gaps in bonding could be visualized and quantified in 3D.




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A temperature-controlled cold-gas humidifier and its application to protein crystals with the humid-air and glue-coating method

The room-temperature experiment has been revisited for macromolecular crystallography. Despite being limited by radiation damage, such experiments reveal structural differences depending on temperature, and it is expected that they will be able to probe structures that are physiologically alive. For such experiments, the humid-air and glue-coating (HAG) method for humidity-controlled experiments is proposed. The HAG method improves the stability of most crystals in capillary-free experiments and is applicable at both cryogenic and ambient temperatures. To expand the thermal versatility of the HAG method, a new humidifier and a protein-crystal-handling workbench have been developed. The devices provide temperatures down to 4°C and successfully maintain growth at that temperature of bovine cytochrome c oxidase crystals, which are highly sensitive to temperature variation. Hence, the humidifier and protein-crystal-handling workbench have proved useful for temperature-sensitive samples and will help reveal temperature-dependent variations in protein structures.




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Protein crystal structure determination with the crystallophore, a nucleating and phasing agent

Obtaining crystals and solving the phase problem remain major hurdles encountered by bio-crystallographers in their race to obtain new high-quality structures. Both issues can be overcome by the crystallophore, Tb-Xo4, a lanthanide-based molecular complex with unique nucleating and phasing properties. This article presents examples of new crystallization conditions induced by the presence of Tb-Xo4. These new crystalline forms bypass crystal defects often encountered by crystallographers, such as low-resolution diffracting samples or crystals with twinning. Thanks to Tb-Xo4's high phasing power, the structure determination process is greatly facilitated and can be extended to serial crystallography approaches.




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Quantifying nanoparticles in clays and soils with a small-angle X-ray scattering method

Clays and soils produce strong small-angle X-ray scattering (SAXS) because they contain large numbers of nanoparticles, namely allophane and ferrihydrite. These nanoparticles are amorphous and have approximately spherical shape with a size of around 3–10 nm. The weight ratios of these nanoparticles will affect the properties of the clays and soils. However, the nanoparticles in clays and soils are not generally quantified and are sometimes ignored because there is no standard method to quantify them. This paper describes a method to quantify nanoparticles in clays and soils with SAXS. This is achieved by deriving normalized SAXS intensities from unit weight of the sample, which are not affected by absorption. By integrating the normalized SAXS intensities over the reciprocal space, one obtains a value that is proportional to the weight ratio of the nanoparticles, proportional to the square of the difference of density between the nanoparticles and the liquid surrounding the nanoparticles, and inversely proportional to the density of the nanoparticles. If the density of the nanoparticles is known, the weight ratio of the nanoparticles can be calculated from the SAXS intensities. The density of nanoparticles was estimated from the chemical composition of the sample. Nanoparticles in colloidal silica, silica gels, mixtures of silica gel and α-aluminium oxide, and synthetic clays have been quantified with the integral SAXS method. The results show that the errors of the weight ratios of nanoparticles are around 25% of the weight ratio. It is also shown that some natural clays contain large fractions of nanoparticles; montmorillonite clay from the Mikawa deposit, pyrophillite clay from the Shokozan deposit and kaolinite clay from the Kanpaku deposit contain 25 (7), 10 (2) and 19 (5) wt% nanoparticles, respectively, where errors are shown in parentheses.




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In meso crystallogenesis. Compatibility of the lipid cubic phase with the synthetic digitonin analogue, glyco-diosgenin

Digitonin has long been used as a mild detergent for extracting proteins from membranes for structure and function studies. As supplied commercially, digitonin is inhomogeneous and requires lengthy pre-treatment for reliable downstream use. Glyco-diosgenin (GDN) is a recently introduced synthetic surfactant with features that mimic digitonin. It is available in homogeneously pure form. GDN is proving to be a useful detergent, particularly in the area of single-particle cryo-electron microscopic studies of membrane integral proteins. With a view to using it as a detergent for crystallization trials by the in meso or lipid cubic phase method, it was important to establish the carrying capacity of the cubic mesophase for GDN. This was quantified in the current study using small-angle X-ray scattering for mesophase identification and phase microstructure characterization as a function of temperature and GDN concentration. The data show that the lipid cubic phase formed by hydrated monoolein tolerates GDN to concentrations orders of magnitude in excess of those used for membrane protein studies. Thus, having GDN in a typical membrane protein preparation should not deter use of the in meso method for crystallogenesis.




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Protein crystal structure determination with the crystallophore, a nucleating and phasing agent

The unique nucleating and phasing capabilities of the crystallophore, Tb-Xo4, are illustrated through challenging cases.




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A temperature-controlled cold-gas humidifier and its application to protein crystals with the humid-air and glue-coating method

A new temperature-controllable humidifier for X-ray diffraction has been developed. It is shown that the humidifier can successfully maintain protein crystal growth at a temperature lower than room temperature.




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High-resolution phonon energy shift measurements with the inelastic neutron spin echo technique

An energy resolution of <10 µeV for the measurement of phonon energy change is achieved with the inelastic neutron spin echo technique on a conventional neutron triple-axis spectrometer.




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Optimization of crystallization of biological macromolecules using dialysis combined with temperature control

This article describes rational strategies for the optimization of crystal growth using precise in situ control of the temperature and chemical composition of the crystallization solution through dialysis, to generate crystals of the specific sizes required for different downstream structure determination approaches.




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Equatorial aberration of powder diffraction data collected with an Si strip X-ray detector by a continuous-scan integration method

Exact and approximate formulas for equatorial aberration of a continuous-scan Si strip detector are compared.




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Dark-field electron holography as a recording of crystal diffraction in real space: a comparative study with high-resolution X-ray diffraction for strain analysis of MOSFETs

A detailed theoretical and experimental comparison of dark-field electron holography (DFEH) and high-resolution X-ray diffraction (HRXRD) is performed. Both techniques are being applied to measure elastic strain in an array of transistors and the role of the geometric phase is emphasized.




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Structure variations within RSi2 and R2Si3 silicides. Part II. Structure driving factors

Most articles dealing with R2TSi3 compounds are only interested in one specific composite or in a series of composites with varying T elements while keeping R fixed (or vice versa). The present work gives an overview of the complete range of 2:1:3 silicides, similar those of Hoffmann & Pöttgen (2001) and Pan et al. (2013). In contrast to the work of Hoffmann & Pöttgen (2001), reasons for formation of the different symmetries and superstructures are discussed. Here, crystallographic properties are in[the] focus, whereas physical and magnetic properties are omitted because those are given by Pan et al. (2013). READS LIKE AN ABSTRACT, please re-write and remove references if possible. Should be two sentences max.




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A new ZnII metallocryptand with unprecedented diflexure helix induced by V-shaped di­imidazole building blocks

A new ZnII metallocryptand is presented, with an unprecedented diflexure helix.




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Crystallographic snapshots of the EF-hand protein MCFD2 complexed with the intracellular lectin ERGIC-53 involved in glycoprotein transport

This article reports conformational polymorphisms of the EF-hand protein MCFD2 which is involved in glycoprotein transport..




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Crystal structure of the Schizosaccharomyces pombe U7BR E2-binding region in complex with Ubc7

Endoplasmic reticulum (ER)-associated degradation (ERAD) is a protein quality-control pathway in eukaryotes in which misfolded ER proteins are polyubiquitylated, extracted and ultimately degraded by the proteasome. This process involves ER membrane-embedded ubiquitin E2 and E3 enzymes, as well as a soluble E2 enzyme (Ubc7 in Saccharomyces cerevisiae and UBE2G2 in mammals). E2-binding regions (E2BRs) that recruit these soluble ERAD E2s to the ER have been identified in humans and S. cerevisiae, and structures of E2–E2BR complexes from both species have been determined. In addition to sequence and structural differences between the human and S. cerevisiae E2BRs, the binding of E2BRs also elicits different biochemical outcomes with respect to E2 charging by E1 and E2 discharge. Here, the Schizosaccharomyces pombe E2BR was identified and purified with Ubc7 to resolve a 1.7 Å resolution co-crystal structure of the E2BR in complex with Ubc7. The S. pombe E2BR binds to the back side of the E2 as an α-helix and, while differences exist, it exhibits greater similarity to the human E2BR. Structure-based sequence alignments reveal differences and conserved elements among these species. Structural comparisons and biochemistry reveal that the S. pombe E2BR presents a steric impediment to E1 binding and inhibits E1-mediated charging, respectively.




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Structure of an RNA helix with pyrimidine mismatches and cross-strand stacking

The structure of a 22-base-pair RNA helix with mismatched pyrimidine base pairs is reported. The helix contains two symmetry-related CUG sequences: a triplet-repeat motif implicated in myotonic dystrophy type 1. The CUG repeat contains a U–U mismatch sandwiched between Watson–Crick pairs. Additionally, the center of the helix contains a dimerized UUCG motif with tandem pyrimidine (U–C/C–U) mismatches flanked by U–G wobble pairs. This region of the structure is significantly different from previously observed structures that share the same sequence and neighboring base pairs. The tandem pyrimidine mismatches are unusual and display sheared, cross-strand stacking geometries that locally constrict the helical width, a type of stacking previously associated with purines in internal loops. Thus, pyrimidine-rich regions of RNA have a high degree of structural diversity.




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STS or Sociology and anthropology with a focus on criminal justice?




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Native bees prove resilient in competition with invasive African honey bees

The spread of Africanized honey bees across Central America has had a much smaller impact on native tropical bee species than scientists previously predicted...

The post Native bees prove resilient in competition with invasive African honey bees appeared first on Smithsonian Insider.




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Remains of William Taylor White (1837-1852) donated to Smithsonian with his coffin and clothing

White, who was a student at Columbian College from Accomack County, Va., died of pneumonia and complications from a mitral heart defect. When his coffin was unearthed, his identity was a deep mystery.

The post Remains of William Taylor White (1837-1852) donated to Smithsonian with his coffin and clothing appeared first on Smithsonian Insider.




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Newly discovered prehistoric turtle co-existed with world’s biggest snake

About as thick as a standard dictionary, this turtle’s shell may have warded off attacks by the Titanoboa, thought to have been the world’s biggest snake, and by other, crocodile-like creatures living in its neighborhood 60 million years ago.

The post Newly discovered prehistoric turtle co-existed with world’s biggest snake appeared first on Smithsonian Insider.




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Super sensitive telescope will detect “killer” asteroids and comets on collision course with Earth

This innovative facility will be at the front line of Earth defense by searching for "killer" asteroids and comets. It will map large portions of the sky nightly, making it an efficient sleuth for not just asteroids but also supernovae and other variable objects.

The post Super sensitive telescope will detect “killer” asteroids and comets on collision course with Earth appeared first on Smithsonian Insider.




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Smithsonian ecologists to examine “dead zones” in Chesapeake Bay with $1.4 million NOAA grant

Breitburg and her team want to determine just how much stress they cause. Over the next five years they will conduct a series of lab and field experiments that examine how diel-cycling hypoxia and the associated acidification affects the growth and disease rates in striped bass, the eastern oyster and other ecologically and economically important Chesapeake Bay species. They will also study the animals’ behavioral responses to these changes.

The post Smithsonian ecologists to examine “dead zones” in Chesapeake Bay with $1.4 million NOAA grant appeared first on Smithsonian Insider.




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Environmental Research Center to help with Chesapeake Bay seagrass restoration

A research team from The Smithsonian Environmental Research Center and Virginia's Old Dominion University will be awarded $110,999 to develop a tool to help seagrass restorers predict which places will be the best for planting seagrasses, the Virginia Sea Grant has announced.

The post Environmental Research Center to help with Chesapeake Bay seagrass restoration appeared first on Smithsonian Insider.




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Smithsonian signs new giant panda agreement with China

The new agreement, effective immediately through Dec. 5, 2015, stipulates that the Smithsonian's National Zoological Park will conduct research in the areas of giant panda breeding and cub behavior.

The post Smithsonian signs new giant panda agreement with China appeared first on Smithsonian Insider.




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Smithsonian researchers help block ship-borne bioinvaders with new screening strategy

To help regulators and engineers develop and test such treatment systems, and ultimately enforce these standards, a team of researchers developed a statistical model to see how to count small, scarce organisms in large volumes of water accurately.

The post Smithsonian researchers help block ship-borne bioinvaders with new screening strategy appeared first on Smithsonian Insider.




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Don’t pick a fight with a eunuch spider. It has nothing to lose

In a recent study of the mating behavior of these Asian spiders, researchers found that 87.5 percent of males had both palps amputated during copulation.

The post Don’t pick a fight with a eunuch spider. It has nothing to lose appeared first on Smithsonian Insider.




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Work of 19th-century oologists enables researcher to track climate change with duck eggs

BROOKINGS, S.D. — Julie DeJong can’t set foot on the ground of an Oregon marsh to gather duck eggs on a spring day in 1875. […]

The post Work of 19th-century oologists enables researcher to track climate change with duck eggs appeared first on Smithsonian Insider.




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Lofty experiments with gliding ants reveals secrets of their unusual flight

One of the most challenging aspects of this research is simply studying these insects as they are falling, says Yanoviak, a tropical arthropod ecologist at the University of Arkansas, Little Rock. Small body size, rapid descent, and the long distances that they can fall, make accurate data taking a challenge.

The post Lofty experiments with gliding ants reveals secrets of their unusual flight appeared first on Smithsonian Insider.




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Scientists show that modern humans never co-existed with Homo erectus

New excavations in Indonesia and dating analyses by scientists at the Smithsonian and their colleagues show that modern humans never co-existed with Homo erectus.

The post Scientists show that modern humans never co-existed with <em>Homo erectus</em> appeared first on Smithsonian Insider.




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Video: A mummy ‘grows’ with CT scans and 3D digital technology

Using 2-dimensional and 3-dimensional CT scans, Natural History Museum anthropologists found that the brain and major organs were removed and rolls of linen filled out the abdominal cavity. This mummification method is evidence of superior embalming, indicating a person of higher status.

The post Video: A mummy ‘grows’ with CT scans and 3D digital technology appeared first on Smithsonian Insider.




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Unlocking the mysteries of Jefferson’s bible with high-tech analysis and microscopic testing

The Life and Morals of Jesus of Nazareth, more commonly known as the Jefferson bible, is a volume created by Thomas Jefferson containing passages he […]

The post Unlocking the mysteries of Jefferson’s bible with high-tech analysis and microscopic testing appeared first on Smithsonian Insider.




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Ability to raft with flotsam and use non-reef habitats helps tropical fish journey to new places, study finds

Depending on where the fish disperse from, the use of ‘stepping stones', flotsam or simply being an adult can help in the journey to find a new home.

The post Ability to raft with flotsam and use non-reef habitats helps tropical fish journey to new places, study finds appeared first on Smithsonian Insider.




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Crab pulsar dazzles astronomers with its gamma-ray beams

The same object that dazzled skygazers in 1054 C.E. continues to dazzle astronomers today by pumping out radiation at higher energies than anyone expected.

The post Crab pulsar dazzles astronomers with its gamma-ray beams appeared first on Smithsonian Insider.




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New genetic evidence confirms coyote migration route to Virginia and hybridization with wolves

In a new study researchers from the Smithsonian Conservation Biology Institute’s Center for Conservation and Evolutionary Genetics used DNA from coyote scat (feces) to trace the route that led some of the animals to colonize in Northern Virginia.

The post New genetic evidence confirms coyote migration route to Virginia and hybridization with wolves appeared first on Smithsonian Insider.




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First Eld’s deer born from in vitro fertilization with help of Smithsonian Conservation Biology Institute scientists

Nearly 20 years after the Smithsonian Conservation Biology Institute became the first to produce an Eld’s deer fawn through artificial insemination, SCBI scientists have now contributed to the birth of the first Eld’s deer via in vitro fertilization.

The post First Eld’s deer born from in vitro fertilization with help of Smithsonian Conservation Biology Institute scientists appeared first on Smithsonian Insider.




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Smithsonian research with DNA barcoding is making seafood substitution easier to catch

Both investigations were carried out through DNA analysis of fish tissue performed in a laboratory using a U.S. Food and Drug Administration protocol that originated largely at the Smithsonian’s National Museum of Natural History. DNA from the fish in question was identified by matching it against a database of DNA fish barcodes that again, has its origins at the Smithsonian.

The post Smithsonian research with DNA barcoding is making seafood substitution easier to catch appeared first on Smithsonian Insider.




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Uganda park rangers with cell phones may help stop next world influenza epidemic

Today, Marra is helping launch an Animal Mortality Monitoring Program in Africa intended to serve as an early warning system for emerging infectious diseases that can pass from animal populations into the human population.

The post Uganda park rangers with cell phones may help stop next world influenza epidemic appeared first on Smithsonian Insider.



  • Q & A
  • Research News
  • Science & Nature
  • mammals
  • Migratory Bird Center
  • Smithsonian Conservation Biology Institute
  • Smithsonian's National Zoo


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As robins disperse, West Nile mosquitoes switch diet to humans: Q&A with Smithsonian ornithologist Peter Marra

A rising spike in West Nile virus is taking health officials across the country by surprise as this year more than 2,600 people in 45 states and the District of Columbia, have been stricken with severe symptoms of this mosquito-transmitted disease.

The post As robins disperse, West Nile mosquitoes switch diet to humans: Q&A with Smithsonian ornithologist Peter Marra appeared first on Smithsonian Insider.




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Rare whale beached in Hawaii infected with deadly marine-mammal virus

A rare Longman’s beaked whale found stranded on the Hawaiian island of Maui in 2010 has scientists in Hawaii on the alert for a deadly disease known as morbillivirus which can lead to high mortality rates in dolphins and other marine mammals.

The post Rare whale beached in Hawaii infected with deadly marine-mammal virus appeared first on Smithsonian Insider.




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Smithsonian launches Global Marine Biodiversity Project with $10 million donation

The goal of the project—the Smithsonian’s Tennenbaum Marine Observatories—is to monitor the ocean’s coastal ecosystems over a long period of time.

The post Smithsonian launches Global Marine Biodiversity Project with $10 million donation appeared first on Smithsonian Insider.




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Galactic thief: “I would have gotten away with it but for those meddling astronomers!”

One of the closest galaxies to the Milky Way almost got away with theft....

The post Galactic thief: “I would have gotten away with it but for those meddling astronomers!” appeared first on Smithsonian Insider.





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Common tropical bat uses echolocation with precision previously considered impossible, new experiments reveal

Using echolocation alone the bats found, identified and captured insects perched motionless and silent on the leaves of plants.

The post Common tropical bat uses echolocation with precision previously considered impossible, new experiments reveal appeared first on Smithsonian Insider.




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New study proves the remora’s sucker disc is in fact a highly modified dorsal fin / Q&A with taxonomist David Johnson

The remora's sucker disc is "one of the most remarkable and most highly modified skeletal structures among vertebrates."

The post New study proves the remora’s sucker disc is in fact a highly modified dorsal fin / Q&A with taxonomist David Johnson appeared first on Smithsonian Insider.




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With no credit to Cupid, white-naped crane couples remain faithful for life

Chris Crowe, keeper of the National Zoo’s 15 white-naped cranes, is well acquainted with the strong attachments these graceful Asian birds form with their mates.

The post With no credit to Cupid, white-naped crane couples remain faithful for life appeared first on Smithsonian Insider.




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Russian Meteor Q&A with Smithsonian Expert Marc Fries

Marc Fries, a research associate in the Smithsonian’s National Museum of Natural History and senior scientist at the Planetary Science Institute in Tucson, answers some basic questions about meteorites.

The post Russian Meteor Q&A with Smithsonian Expert Marc Fries appeared first on Smithsonian Insider.