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<jats:p> This issue of <jats:italic>Science</jats:italic> includes the program of the 2022 AAAS Annual Meeting. The hybrid 2022 AAAS Annual Meeting will be held in Philadelphia, and online, February 17-20. Registration and program are now available! The theme of the AAAS Annual Meeting is <jats:italic>Empower With Evidence</jats:italic> . </jats:p> <jats:p> For more information on the meeting, please visit <jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="www.aaas.org/meetings/">www.aaas.org/meetings/</jats:ext-link> . </jats:p>

<jats:title>Using carbon-14</jats:title> <jats:p> Carbon-14 or radiocarbon, a radioactive isotope produced in the upper atmosphere by cosmic rays, is rapidly incorporated into the terrestrial carbon cycle and provides a way to calculate the age of carbon-bearing materials as old as 55,000 years. Heaton <jats:italic>et al</jats:italic> . review recent progress that has allowed the construction of better radiocarbon age calibration curves and discuss the new insights into climate processes, the Sun, Earth’s geodynamo, and the carbon cycle that have emerged from these efforts. —HJS </jats:p>

<jats:title>AMPlifying type 2 immunity</jats:title> <jats:p> Antimicrobial proteins (AMPs) are a frontline defense against pathogenic microorganisms at mucosal surfaces. These cationic molecules inactivate their targets primarily by disrupting cell walls and membranes. Hu <jats:italic>et al</jats:italic> . found that small proline-rich protein 2A (SPRR2A) is a bactericidal protein produced in the gut that targets Gram-positive bacteria and is phylogenetically distinct from all other known AMPs (see the Perspective by Harris and Wickramasinghe). SPRR2A production is selectively enhanced by type 2 cytokines such as interleukin-4 and -13 that are elicited by helminth infection. Mice lacking SPRR2A are unable to prevent intestinal bacteria from invading the intestinal barrier after helminths damage the intestinal epithelium. SPRR2A is thus a critical component of type 2 immunity that protects against the bacterial invasion and dissemination that follow helminth infection. —STS </jats:p>

<jats:title>Selective subatomic separations</jats:title> <jats:p> Membranes are thin materials used to selectively separate gases or liquids and are used on a range of scales from benchtop experiments to industrial processes. Challenges arise in separating materials with very similar sizes or chemical properties, particularly at the smallest scales. Kidambi <jats:italic>et al</jats:italic> . review advances in using atomically thin two-dimensional materials such as graphene or hexagonal boron nitride for the separation of subatomic species, including electrons, hydrogen isotopes, and gases. The authors explore the scope to scale up the sizes of these membranes and their potential use in applications relating to energy, microscopy, and electronics. —MSL </jats:p>

<jats:title>Synapse stabilization</jats:title> <jats:p> Early in brain development, neurons connect to each other enthusiastically. With development, an overabundance of synapses is winnowed down to refine efficiently connected circuits. Inactive synapses are prime targets for elimination, whereas active synapses tend to be retained. Gomez-Castro <jats:italic>et al</jats:italic> . took a closer look at how those choices are made (see the Perspective by Blum and Lopes). When postsynaptic adenosine receptors are muted or do not find enough extracellular adenosine, synapses get eliminated. Neurotransmitter-dependent signaling pathways drive protein kinase A to phosphorylate the postsynaptic scaffolding molecule gephyrin. Together with a partner synaptogenic membrane protein, gephyrin is required for the stabilization of γ-aminobutyric acid receptors. Adenosine receptors thus detect synaptic activity and in turn drive the stabilization of synapses that produce such activity. —PJH </jats:p>

<jats:p> A recent <jats:italic>Science</jats:italic> editorial on the social and political headwinds that have blunted, obfuscated, and confused public behavior in the United States’ COVID-19 response cautioned both politicians who appoint themselves scientists and scientists—including virologists and epidemiologists—to stay in their lanes. The warning raises an important question: Should science add another lane? </jats:p>

<jats:p>As nations look to cut emissions of the gas, some researchers want to pull it out of the air</jats:p>

<jats:p>Skin and nerves from pigs lacking immune-provoking sugar could help patients today</jats:p>