Phragmites australis, the common reed, has been a component of North American marshes for thousands of years. However, a novel genetic lineage, Phragmites australis australis, […]

The post Climate change conundrum: Invasive reed makes much more methane appeared first on Smithsonian Insider.

Shallow-water seagrasses can’t survive without enough light. And fish, shrimp, crabs and other creatures we rely on for food can’t survive without seagrasses. Smithsonian biologist […]

The post Ecosystems on the Edge: Underwater Light and Seagrass appeared first on Smithsonian Insider.

When scientists discuss global change, they often focus on the amount of carbon in the atmosphere and vegetation. But soil contains more carbon than air […]

The post Fungi may determine the future of soil carbon appeared first on Smithsonian Insider.

A 57-acre research plot at a University of Michigan forest preserve northwest of Ann Arbor has been added to a Smithsonian Institution global network used […]

The post University of Michigan forest preserve joins Smithsonian global network appeared first on Smithsonian Insider.

We know some types of fungi turn ants into zombies, but fungi are not always the bad guys. In the case of orchids, fungi are […]

The post The Secret Life of Orchids – Part I: Fungi appeared first on Smithsonian Insider.

This year’s El Niño event is one of the strongest on record and is still ramping up. Large parts of the tropics are turning into […]

The post Major El Nino Perfect opportunity for Global Change Research appeared first on Smithsonian Insider.

Rattlesnake, zebra and peacock plants have a new wild relative, discovered by Rodolfo Flores, Panamanian botanist and intern at the Smithsonian Tropical Research Institute (STRI). […]

The post Smithsonian Botanist Discovers New Ground-Flowering Plant in Panama appeared first on Smithsonian Insider.

With net in hand and eyes peeled, Mauren Turcatel spent two-weeks last October chasing blood-thirsty predators through the Amazon jungle of Brazil. One-by-one they appeared […]

The post Blood-thirsty jungle horse-flies catch big chill from Smithsonian entomologist appeared first on Smithsonian Insider.

Profound ideas don’t need to be complicated. A simple cube made of aluminum tubing, a centerpiece of a new exhibit “Life in One Cubic Foot,” […]

The post From Rochester to Polynesia, a simple cube unveils Earth’s dazzling biological diversity appeared first on Smithsonian Insider.

In the dark recesses of an underground fungus garden, a Panamanian leaf-cutting ant plucks a tuft of mycelia, the wispy part of the basidiomycete fungus […]

The post Mystery solved? Ants Protect Young From Infection By Cocooning Them in Fungus appeared first on Smithsonian Insider.

By now, most of the United States has started to feel the first cool caresses of winter. Everything is pumpkin spiced, and the last crickets […]

The post Feathered diplomats unite pupils in North and Central America appeared first on Smithsonian Insider.

Coastal marine environments are impacted by human disturbance. Dock pilings allow MarineGEO researchers to study these impacts in a standardized way around the world to […]

The post The incredible marine diversity under boat docks appeared first on Smithsonian Insider.

If you are a plant, when life aboveground turns harsh, you have few options. Some orchids respond by going dormant, spending years to decades underground […]

The post Dormant Orchids Need Fungi to Rise Again appeared first on Smithsonian Insider.

Living trees can rot from the inside out, leaving only a hollowed trunk. Wood rot in living trees can cause overestimates of global carbon pools, […]

The post Measuring trees with the speed of sound appeared first on Smithsonian Insider.

Caribbean coral reefs have become biologically and economically degraded habitats. The relative weight of the big factors in this ecological catastrophe–pollution, overfishing, warming and ocean […]

The post Coral reefs grow faster, healthier when parrotfish are abundant appeared first on Smithsonian Insider.

A tiny invasive insect from Asia might have an effect on Chesapeake Bay waters. The emerald ash borer is killing millions of ash trees in […]

The post Invasive ash borer found in Smithsonian Environmental Research Center forest; ash deaths may impact Chesapeake waters appeared first on Smithsonian Insider.

Coral reefs are home to some of the most colorful, diverse life on the planet. And yet, for all their fame as biodiversity hotspots, it’s […]

The post Coral reef eavesdropping unveils burrowed, romantic male singers appeared first on Smithsonian Insider.

To catch lizards on the offshore islands close to St. Croix in the Caribbean, Smithsonian herpetologist Nicole Angeli uses a lasso of thread looped at […]

The post Mongooses wiped them out. Now Nicole Angeli wants the St. Croix ground lizard home again appeared first on Smithsonian Insider.

How specific fungi interact with seeds in tropical forest soils may be the ultimate arbiter in the struggle for survival among tropical trees. “Depending on […]

The post Study reveals soil fungi has final say in survival of seeds from tropical trees appeared first on Smithsonian Insider.

White-tailed deer don’t like to eat the invasive plants Japanese stilt grass, garlic mustard or barberry. Native oak seedlings and tulip poplar, on the other […]

The post Too many hungry deer are lowering diversity of native plants in eastern U.S. forests appeared first on Smithsonian Insider.

Long before colonists landed on the shores of New England, Native Americans harvested cranberries from peaty bogs and marshes. Following the Pilgrims reliance on the […]

The post The cranberry: America’s founding fruit appeared first on Smithsonian Insider.

Each year from summer into fall, ornamental crape myrtle trees in the southern and central U.S. lay out a visual feast of vibrant flowers in […]

The post Crape myrtle trees aren’t native to the US, but hungry native birds still find them tasty appeared first on Smithsonian Insider.

The cationic cyclo­metallated iridium(III) complex [Ir(C9H7N2)2(C12H8N2)](PF6) has been synthesized and crystallized by the inter-diffusion method. It contains an unknown number of solvent mol­ecules and has a different space-group symmetry (C2/c) structure than its solvatomorph (P21/c).

It is shown how to reconstruct the stacking sequence from the pairwise correlation functions between layers in close-packed structures. First, of theoretical interest, the analytical formulation and solution of the problem are presented when the exact pairwise correlation counts are known. In the second part, the practical problem is approached. A simulated annealing procedure is developed to solve the problem using as initial guess approximate solutions from previous treatments. The robustness of the procedure is tested with synthetic data, followed by an experimental example. The developed approach performs robustly over different synthetic and experimental data, comparing favorably with the reported methods.

This work considers the scaling properties characterizing the hyperuniformity (or anti-hyperuniformity) of long-wavelength fluctuations in a broad class of one-dimensional substitution tilings. A simple argument is presented which predicts the exponent α governing the scaling of Fourier intensities at small wavenumbers, tilings with α > 0 being hyperuniform, and numerical computations confirm that the predictions are accurate for quasiperiodic tilings, tilings with singular continuous spectra and limit-periodic tilings. Quasiperiodic or singular continuous cases can be constructed with α arbitrarily close to any given value between −1 and 3. Limit-periodic tilings can be constructed with α between −1 and 1 or with Fourier intensities that approach zero faster than any power law.

When creating a System Composer architecture model, if the following functions are called with an invalid or missing stereotype, it can cause the model to get corrupted and might lead to a MATLAB crash:

• addComponent
• addPort
• connect

The GDC Compliance Advisory Board (CAB) provides insight into how to interpret the Strong Consumer Authentication (SCA) mandate described in PSD 2 without jeopardizing data privacy concerns protected by GDPR. 

The cationic complex in the title compound, [Ir(C9H7N2)2(C12H8N2)]PF6, comprises two phenylpyrazole (ppz) cyclometallating ligands and one 1,10-phenanthroline (phen) ancillary ligand. The asymmetric unit consists of one [Ir(ppz)2(phen)]+ cation and one [PF6]− counter-ion. The central IrIII ion is six-coordinated by two N atoms and two C atoms from the two ppz ligands as well as by two N atoms from the phen ligand within a distorted octahedral C2N4 coordination set. In the crystal structure, the [Ir(ppz)2(phen)]+ cations and PF6− counter-ions are connected with each other through weak intermolecular C—H...F hydrogen bonds. Additional C—H...π interactions between the rings of neighbouring cations consolidate the three-dimensional network. Electron density associated with additional disordered solvent molecules inside cavities of the structure was removed with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s). The title compound has a different space-group symmetry (C2/c) from its solvatomorph (P21/c) comprising 1.5CH2Cl2 solvent molecules per ion pair.

The enanti­opure monopyrrolidine derivative (2S)-methyl (Z)-5-(2-tert-but­oxy-1-cyano-2-oxo­ethyl­idene)pyrrolidine-2-carboxyl­ate, C13H18N2O4, (1), represents a potential ligand and an attractive inter­mediate for the synthesis of chiral metal com­plexes. At the mol­ecular level, the com­pound features an intra­molecular N—H⋯O hydrogen bond; neighbouring mol­ecules inter­act via N—H⋯N contacts to form chains along [100]. Due to its elemental com­position, resonant scattering of the target com­pound is entirely insignificant for diffraction experiments with Mo Kα and small even for Cu Kα radiation. A preliminary study with the harder radiation type confirmed the chiral space group and the suitability of the single crystal chosen; as expected, the results concerning the absolute structure remained com­pletely inconclusive. A second data collection with the longer wavelength gave satisfactory quality indicators for the correct handedness of the mol­ecule, albeit with high standard uncertainties. The absolute configuration has been assessed independently: CD spectra for both enanti­omers of the target mol­ecule were calculated and the spectrum for the S-configured stereoisomer was in agreement with the experiment. The Cotton effect of (1) may be ascribed to π–π* transitions from HOMO to LUMO and from HOMO to LUMO+1. As both independent techniques agree with respect to the handedness of the target mol­ecule, the absolute structure may be assigned with a high degree of confidence.

The positional change of nitro­gen-7 of the RNA constituent guanosine to the bridgehead position-5 leads to the base-modified nucleoside 5-aza-7-de­aza­guanosine. Contrary to guanosine, this mol­ecule cannot form Hoogsteen base pairs and the Watson–Crick proton donor site N3—H becomes a proton-acceptor site. This causes changes in nucleobase recognition in nucleic acids and has been used to construct stable `all-purine' DNA and DNA with silver-mediated base pairs. The present work reports the single-crystal X-ray structure of 7-iodo-5-aza-7-de­aza­guanosine, C10H12IN5O5 (1). The iodinated nucleoside shows an anti conformation at the glycosylic bond and an N conformation (O4'-endo) for the ribose moiety, with an anti­periplanar orientation of the 5'-hy­droxy group. Crystal packing is controlled by inter­actions between nucleobase and sugar moieties. The 7-iodo substituent forms a contact to oxygen-2' of the ribose moiety. Self-pairing of the nucleobases does not take place. A Hirshfeld surface analysis of 1 highlights the contacts of the nucleobase and sugar moiety (O—H⋯O and N—H⋯O). The concept of pK-value differences to evaluate base-pair stability was applied to purine–purine base pairing and stable base pairs were predicted for the construction of `all-purine' RNA. Furthermore, the 7-iodo substituent of 1 was functionalized with benzo­furan to detect motional constraints by fluorescence spectroscopy.

Structure-mining finds and returns the best-fit structures from structural databases given a measured pair distribution function data set. Using databases and heuristics for automation it has the potential to save experimenters a large amount of time as they explore candidate structures from the literature.

The Debye scattering equation (DSE) is generalized and augmented in order to account for moderate texture effects, yielding the differential cross section as a function of atomic coordinates and texture coefficients subject to symmetry constraints. Implications for the evaluation of the pair distribution function (PDF) as a direct transform of powder diffraction data from textured samples are also discussed.

The analytical solution of the problem of X-ray spherical-wave Laue diffraction in a single crystal with a linear change of thickness on the exit surface is derived. General equations are applied to a specific case of plane-wave Laue diffraction in a thick crystal under the conditions of the Borrmann effect.

(The Paypers) AML data and tech company Vital4 has revealed its partnership with UK-based