Nature
The cannabis crop
The cannabis crop
Nature. doi:10.1038/525S2a
Author: Julie Gould
Cannabis is one of humanity's oldest cultivated crops. But despite its long history and many uses, hard facts on its evolution and impact on the human body are in short supply. By Julie Gould.
Botany: The cultivation of weed
Botany: The cultivation of weed
Nature. doi:10.1038/525S4a
Author: Lucas Laursen
Researchers are getting closer to answering the centuries-old question of how to label cannabis varieties — a necessary step to bring the plant into mainstream agriculture.
Drug development: The treasure chest
Drug development: The treasure chest
Nature. doi:10.1038/525S6a
Author: Brian Owens
Pharmaceutical research into the chemicals found in cannabis has so far supplied only one licensed medicine. But scientists think there could be hundreds more.
Perspective: Close the knowledge gap
Perspective: Close the knowledge gap
Nature. doi:10.1038/525S9a
Authors: Jonathan Page & Mark Ware
Nations with cannabis programmes should respond to a lack of research. Canada can be a leader, say Jonathan Page and Mark Ware.
A potted history
A potted history
Nature. doi:10.1038/525S10a
Author: Stephanie Pain
For thousands of years cannabis has been valued as a versatile herbal medicine. In the twentieth century, prescription gave way to proscription. Might this ancient remedy be about to regain its healing reputation? By Stephanie Pain
Israel: Research without prejudice
Israel: Research without prejudice
Nature. doi:10.1038/525S12a
Author: Emily Sohn
How one Mediterranean country is pushing the frontiers of medical cannabis knowledge.
Perspective: Be clear about the real risks
Perspective: Be clear about the real risks
Nature. doi:10.1038/525S14a
Author: Matthew Hill
The assertion that cannabis use can cause schizophrenia is not borne out by the evidence, says Matthew Hill.
Medical marijuana: Showdown at the cannabis corral
Medical marijuana: Showdown at the cannabis corral
Nature. doi:10.1038/525S15a
Author: Michael Eisenstein
Researchers are gathering clinical data for medical marijuana against a backdrop of deregulation and opportunism.
Cannabis: 4 big questions
Cannabis: 4 big questions
Nature. doi:10.1038/525S18a
Author: Julie Gould
As restrictions around cannabis research ease, scientists are exploring how the plant could be medically useful. Here are four of the hardest questions they face.
Marine science: Storms bring ocean nutrients to light
Marine science: Storms bring ocean nutrients to light
Nature 525, 7570 (2015). doi:10.1038/525460a
Authors: Jaime Palter
Ships and ocean-observing robots have been used to quantify the amount of nutrients that a storm brings up from the Stygian ocean depths to the sunlit surface — a first step in assessing how storms affect oceanic biomass production.
Nuclear physics: Neutrons with a twist
Nuclear physics: Neutrons with a twist
Nature 525, 7570 (2015). doi:10.1038/525462a
Authors: Robert W. Boyd
Neutrons do not normally have orbital angular momentum. But the demonstration that a beam of neutrons can acquire this property, 23 years after it was shown in photons, offers the promise of improved imaging technologies. See Letter p.504
Evolutionary biology: Infection elevates diversity
Evolutionary biology: Infection elevates diversity
Nature 525, 7570 (2015). doi:10.1038/525464a
Authors: Aneil F. Agrawal
Chromosomal shuffling in parental eggs or sperm can create new characteristics in the next generation. In fruit flies, it seems that mothers with a parasitic infection produce more such recombinant offspring than uninfected mothers.
Computational astrophysics: Monstrous galaxies unmasked
Computational astrophysics: Monstrous galaxies unmasked
Nature 525, 7570 (2015). doi:10.1038/525465a
Authors: Romeel Davé
The enigma of how the most luminous galaxies arise is closer to being solved. New simulations show that these are long-lived massive galaxies powered by prodigious gas infall and the recycling of supernova-driven outflows. See Letter p.496
Hallmarks of pluripotency
Hallmarks of pluripotency
Nature 525, 7570 (2015). doi:10.1038/nature15515
Authors: Alejandro De Los Angeles, Francesco Ferrari, Ruibin Xi, Yuko Fujiwara, Nissim Benvenisty, Hongkui Deng, Konrad Hochedlinger, Rudolf Jaenisch, Soohyun Lee, Harry G. Leitch, M. William Lensch, Ernesto Lujan, Duanqing Pei, Janet Rossant, Marius Wernig, Peter J. Park & George Q. Daley
Stem cells self-renew and generate specialized progeny through differentiation, but vary in the range of cells and tissues they generate, a property called developmental potency. Pluripotent stem cells produce all cells of an organism, while multipotent or unipotent stem cells regenerate only specific lineages or tissues. Defining stem-cell potency relies upon functional assays and diagnostic transcriptional, epigenetic and metabolic states. Here we describe functional and molecular hallmarks of pluripotent stem cells, propose a checklist for their evaluation, and illustrate how forensic genomics can validate their provenance.
The formation of submillimetre-bright galaxies from gas infall over a billion years
The formation of submillimetre-bright galaxies from gas infall over a billion years
Nature 525, 7570 (2015). doi:10.1038/nature15383
Authors: Desika Narayanan, Matthew Turk, Robert Feldmann, Thomas Robitaille, Philip Hopkins, Robert Thompson, Christopher Hayward, David Ball, Claude-André Faucher-Giguère & Dušan Kereš
Submillimetre-bright galaxies at high redshift are the most luminous, heavily star-forming galaxies in the Universe and are characterized by prodigious emission in the far-infrared, with a flux of at least five millijanskys at a wavelength of 850 micrometres. They reside in haloes with masses about 1013 times that of the Sun, have low gas fractions compared to main-sequence disks at a comparable redshift, trace complex environments and are not easily observable at optical wavelengths. Their physical origin remains unclear. Simulations have been able to form galaxies with the requisite luminosities, but have otherwise been unable to simultaneously match the stellar masses, star formation rates, gas fractions and environments. Here we report a cosmological hydrodynamic galaxy formation simulation that is able to form a submillimetre galaxy that simultaneously satisfies the broad range of observed physical constraints. We find that groups of galaxies residing in massive dark matter haloes have increasing rates of star formation that peak at collective rates of about 500–1,000 solar masses per year at redshifts of two to three, by which time the interstellar medium is sufficiently enriched with metals that the region may be observed as a submillimetre-selected system. The intense star formation rates are fuelled in part by the infall of a reservoir gas supply enabled by stellar feedback at earlier times, not through major mergers. With a lifetime of nearly a billion years, our simulations show that the submillimetre-bright phase of high-redshift galaxies is prolonged and associated with significant mass buildup in early-Universe proto-clusters, and that many submillimetre-bright galaxies are composed of numerous unresolved components (for which there is some observational evidence).
Controlling neutron orbital angular momentum
Controlling neutron orbital angular momentum
Nature 525, 7570 (2015). doi:10.1038/nature15265
Authors: Charles W. Clark, Roman Barankov, Michael G. Huber, Muhammad Arif, David G. Cory & Dmitry A. Pushin
The quantized orbital angular momentum (OAM) of photons offers an additional degree of freedom and topological protection from noise. Photonic OAM states have therefore been exploited in various applications ranging from studies of quantum entanglement and quantum information science to imaging. The OAM states of electron beams have been shown to be similarly useful, for example in rotating nanoparticles and determining the chirality of crystals. However, although neutrons—as massive, penetrating and neutral particles—are important in materials characterization, quantum information and studies of the foundations of quantum mechanics, OAM control of neutrons has yet to be achieved. Here, we demonstrate OAM control of neutrons using macroscopic spiral phase plates that apply a ‘twist’ to an input neutron beam. The twisted neutron beams are analysed with neutron interferometry. Our techniques, applied to spatially incoherent beams, demonstrate both the addition of quantum angular momenta along the direction of propagation, effected by multiple spiral phase plates, and the conservation of topological charge with respect to uniform phase fluctuations. Neutron-based studies of quantum information science, the foundations of quantum mechanics, and scattering and imaging of magnetic, superconducting and chiral materials have until now been limited to three degrees of freedom: spin, path and energy. The optimization of OAM control, leading to well defined values of OAM, would provide an additional quantized degree of freedom for such studies.
Cell-fate determination by ubiquitin-dependent regulation of translation
Cell-fate determination by ubiquitin-dependent regulation of translation
Nature 525, 7570 (2015). doi:10.1038/nature14978
Authors: Achim Werner, Shintaro Iwasaki, Colleen A. McGourty, Sofia Medina-Ruiz, Nia Teerikorpi, Indro Fedrigo, Nicholas T. Ingolia & Michael Rape
Metazoan development depends on the accurate execution of differentiation programs that allow pluripotent stem cells to adopt specific fates. Differentiation requires changes to chromatin architecture and transcriptional networks, yet whether other regulatory events support cell-fate determination is less well understood. Here we identify the ubiquitin ligase CUL3 in complex with its vertebrate-specific substrate adaptor KBTBD8 (CUL3KBTBD8) as an essential regulator of human and Xenopus tropicalis neural crest specification. CUL3KBTBD8 monoubiquitylates NOLC1 and its paralogue TCOF1, the mutation of which underlies the neurocristopathy Treacher Collins syndrome. Ubiquitylation drives formation of a TCOF1–NOLC1 platform that connects RNA polymerase I with ribosome modification enzymes and remodels the translational program of differentiating cells in favour of neural crest specification. We conclude that ubiquitin-dependent regulation of translation is an important feature of cell-fate determination.
In the name of beauty
In the name of beauty
Nature 525, 7570 (2015). doi:10.1038/525425a
The ugly truth is that the plastic microbeads found in many skin scrubs and other personal-care products are a serious pollutant of the marine environment. They should be phased out rapidly.
UN approves global to-do list for next 15 years
UN approves global to-do list for next 15 years
Nature 525, 7570 (2015). http://www.nature.com/doifinder/10.1038/525434a
Author: Jeff Tollefson
Sustainable development goals aim to wipe out poverty without wrecking the environment.