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A very precise measurement of the magnetic moment of a single electron bound to a carbon nucleus, combined with a state-of-the-art calculation in the framework of bound-state quantum electrodynamics, gives a new value of the atomic mass of the electron that is more precise than the currently accepted one by a factor of 13. Electron mass to unprecedented precision The atomic mass of the electron is a key parameter for fundamental physics. A precise determination is a challenge because the mass is so low. Sven Sturm and colleagues report on a new determination of the electron's mass in atomic units. The authors measured the magnetic moment of a single electron bound to a reference ion (a bare nucleus of carbon-12). The results were analysed using state-of-the-art quantum electrodynamics theory to yield a mass value with a precision that exceeds the current literature value by more than an order of magnitude. The quest for the value of the electron’s atomic mass has been the subject of continuing efforts over the past few decades 1 , 2 , 3 , 4 . Among the seemingly fundamental constants that parameterize the Standard Model of physics 5 and which are thus responsible for its predictive power, the electron mass m e is prominent, being responsible for the structure and properties of atoms and molecules. It is closely linked to other fundamental constants, such as the Rydberg constant R ∞ and the fine-structure constant α (ref. 6 ). However, the low mass of the electron considerably complicates its precise determination. Here we combine a very precise measurement of the magnetic moment of a single electron bound to a carbon nucleus with a state-of-the-art calculation in the framework of bound-state quantum electrodynamics. The precision of the resulting value for the atomic mass of the electron surpasses the current literature value of the Committee on Data for Science and Technology (CODATA 6 ) by a factor of 13. This result lays the foundation for future fundamental physics experiments 7 , 8 and precision tests of the Standard Model 9 , 10 , 11 .

Inner-shell electrons naturally sense the electric field close to the nucleus, which can reach extreme values beyond 10 15  V cm −1 for the innermost electrons 1 . Especially in few-electron, highly charged ions, the interaction with the electromagnetic fields can be accurately calculated within quantum electrodynamics (QED), rendering these ions good candidates to test the validity of QED in strong fields. Consequently, their Lamb shifts were intensively studied in the past several decades 2 , 3 . Another approach is the measurement of gyromagnetic factors ( g factors) in highly charged ions 4 – 7 . However, so far, either experimental accuracy or small field strength in low- Z ions 5 , 6 limited the stringency of these QED tests. Here we report on our high-precision, high-field test of QED in hydrogen-like 118 Sn 49+ . The highly charged ions were produced with the Heidelberg electron beam ion trap (EBIT) 8 and injected into the ALPHATRAP Penning-trap setup 9 , in which the bound-electron g factor was measured with a precision of 0.5 parts per billion (ppb). For comparison, we present state-of-the-art theory calculations, which together test the underlying QED to about 0.012%, yielding a stringent test in the strong-field regime. With this measurement, we challenge the best tests by means of the Lamb shift and, with anticipated advances in the g -factor theory, surpass them by more than an order of magnitude. A high-precision, high-field test of quantum electrodynamics measuring the bound-electron g factor in hydrogen-like tin is described, which—together with state-of-the-art theory calculations—yields a stringent test in the strong-field regime.

State-of-the-art optical clocks 1 achieve precisions of 10 −18 or better using ensembles of atoms in optical lattices 2 , 3 or individual ions in radio-frequency traps 4 , 5 . Promising candidates for use in atomic clocks are highly charged ions 6 (HCIs) and nuclear transitions 7 , which are largely insensitive to external perturbations and reach wavelengths beyond the optical range 8 that are accessible to frequency combs 9 . However, insufficiently accurate atomic structure calculations hinder the identification of suitable transitions in HCIs. Here we report the observation of a long-lived metastable electronic state in an HCI by measuring the mass difference between the ground and excited states in rhenium, providing a non-destructive, direct determination of an electronic excitation energy. The result is in agreement with advanced calculations. We use the high-precision Penning trap mass spectrometer PENTATRAP to measure the cyclotron frequency ratio of the ground state to the metastable state of the ion with a precision of 10 −11 —an improvement by a factor of ten compared with previous measurements 10 , 11 . With a lifetime of about 130 days, the potential soft-X-ray frequency reference at 4.96 × 10 16 hertz (corresponding to a transition energy of 202 electronvolts) has a linewidth of only 5 × 10 −8 hertz and one of the highest electronic quality factors (10 24 ) measured experimentally so far. The low uncertainty of our method will enable searches for further soft-X-ray clock transitions 8 , 12 in HCIs, which are required for precision studies of fundamental physics 6 . Penning trap mass spectrometry is used to measure the electronic transition energy from a long-lived metastable state to the ground state in highly charged rhenium ions with a precision of 10 −11 .

Water surface greenhouse gas (GHG) emissions in freshwater reservoirs are closely related to limnological processes in the water column. Affected by both reservoir operation and seasonal changes, variations in the hydro-morphological conditions in the river–reservoir continuum will create distinctive patterns in water surface GHG emissions. A one-year field survey was carried out in the Pengxi River–reservoir continuum, a part of the Three Gorges Reservoir (TGR) immediately after the TGR reached its maximum water level. The annual average water surface CO 2 and CH 4 emissions at the riverine background sampling sites were 6.23 ± 0.93 and 0.025 ± 0.006 mmol h −1  m −2 , respectively. The CO 2 emissions were higher than those in the downstream reservoirs. The development of phytoplankton controlled the downstream decrease in water surface CO 2 emissions. The presence of thermal stratification in the permanent backwater area supported extensive phytoplankton blooms, resulting in a carbon sink during several months of the year. The CH 4 emissions were mainly impacted by water temperature and dissolved organic carbon. The greatest water surface CH 4 emission was detected in the fluctuating backwater area, likely due to a shallower water column and abundant organic matter. The Pengxi River backwater area did not show significant increase in water surface GHG emissions reported in tropical reservoirs. In evaluating the net GHG emissions by the impoundment of TGR, the net change in the carbon budget and the contribution of nitrogen and phosphorus should be taken into consideration in this eutrophic river–reservoir continuum.

Herein hyperbranched polyethyleneimine (hPEI) cryogels are reported for the selective and reversible adsorption of elemental chlorine. The cryogels are prepared in an aqueous solution by crosslinking with glutaraldehyde at subzero temperatures. The final macroporous composites bearing ammonium chloride groups are obtained after freeze‐drying. The cryogels CG1[Cl]–CG3[Cl] adsorb chlorine with capacities of 0.22–0.26 g Cl2/g cryogel as an average over three adsorption‐desorption cycles. The adsorption process is based on the reversible and selective halogen bonding of chlorides (Cl−) with chlorine (Cl2) forming the corresponding trichloride ([Cl3]−) species, indicated by Raman spectroscopy. The reversibility of chlorine adsorption is shown by applying heat and vacuum to the loaded cryogel CG1[Cl3] releasing 63% of the adsorbed chlorine within 3 h and 72% within 16 h. The unique ability to selectively adsorb chlorine in the presence of other gases is successfully employed for the selective adsorption of chlorine from a gas mixture, potentially enabling the recycling of chlorine from tail gas streams. Quaternized polyethyleneimine‐based cryogels CG[Cl] are used for the reversible adsorption of chlorine. The chlorine is adsorbed by chemisorption forming the corresponding trichlorides CG[Cl3] by halogen bonding. Using these cryogels, chlorine is selectively adsorbed in the presence of oxygen and nitrogen potentially enabling gas separation processes in the chemical industry.

Background There are limited options for the treatment of behavioral and psychological symptoms of dementia (BPSD). Objective Evaluate the efficacy and safety of using atypical antipsychotics for BPSD among patients residing in long-term care. Setting Long term care community facility in the United States. Methods Retrospective observational study of patients residing in a long-term care facility with a diagnosis of dementia not trauma-induced with documented BPSD treated with an atypical antipsychotic for at least 2 weeks. Paper medical records were reviewed from January 1, 1990 until March 23, 2010. Main outcome measure Behavioral/psychological efficacy outcomes were documented beginning 2 weeks after atypical antipsychotic therapy was initiated and safety outcomes were documented from the time of atypical antipsychotic initiation, until the last documentation available. Efficacy and safety outcomes were documented as part of routine clinical practice based on the responsible clinician. Results A total of 85 distinct atypical antipsychotic treatment periods for 73 unique patients were included. Nearly 50% of patients continued atypical antipsychotic treatment for at least 1 year and 5.6% of treatments were discontinued due to an adverse event. Patients’ behavioral/psychological outcomes improved for 52 (61%) treatments, remained stable for 17 (20%) treatments, and worsened for 16 (19%) treatments. Adverse events were reported by 57% of patients, with the most common adverse events being metabolic, fall related, and extrapyramidal symptoms. The odds ratio for an adverse event was 1.08 (p = 0.03) for every 90 day increase in duration of treatment. Conclusion In patients who reside in a long-term care setting, atypical antipsychotic treatment improved BPSD, but also increased the potential risk of adverse events.

Much research has asserted that high shear forces are necessary for the formation of aerobic granular sludge in Sequencing Batch Reactors (SBRs). In order to distinguish the role of shear and dissolved oxygen on granule formation, two separate experiments were conducted with three bench-scale SBRs. In the first experiment, an SBR was operated with five sequentially decreasing superficial upflow gas velocities ranging from 1.2 to 0.4 cm s−1. When less than 1 cm s−1 shear was applied to the reactor, aerobic granules disintegrated into flocs, with corresponding increases in SVI and effluent suspended solids. However, the dissolved oxygen also decreased from 8 mg L−1 to 5 mg L−1, affecting the Feast/Famine regime in the SBR and the substrate removal kinetics. A second experiment operated two SBRs with an identical shear force of 1.2 cm s−1, but two dissolved oxygen concentrations. Even when supplied a high shear force, aerobic granules could not form at a dissolved oxygen less than 5 mg L−1, with a Static Fill. These results indicate that the substrate removal kinetics and dissolved oxygen are more significant to granule formation than shear force.

The rare-earth crisis, which peaked in the summer of 2011 with the prices of both light and heavy rare earths soaring to unprecedented levels, brought about the widespread realization that the long-term availability and price stability of rare earths could not be guaranteed. This triggered a rapid response from manufacturers involved in rare earths, as well as governments and national and international funding agencies. In the case of rare-earth-containing permanent magnets, three possibilities were given quick and serious consideration: (I) increased recycling of devices containing rare earths; (II) the search for new, mineable, rare-earth resources beyond those in China; and (III) the development of high-energy-product permanent magnets with little or no rare-earth content used in their manufacture. The Replacement and Original Magnet Engineering Options (ROMEO) project addresses the latter challenge using a two-pronged approach. With its basis on work packages that include materials modeling and advanced characterization, the ROMEO project is an attempt to develop a new class of novel permanent magnets that are free of rare earths. Furthermore, the project aims to minimize rare-earth content, particularly heavy-rare-earth (HRE) content, as much as possible in Nd-Fe-B-type magnets. Success has been achieved on both fronts. In terms of new, rare-earth-free magnets, a Heusler alloy database of 236,945 compounds has been narrowed down to approximately 20 new compounds. Of these compounds, Co 2 MnTi is expected to be a ferromagnet with a high Curie temperature and a high magnetic moment. Regarding the reduction in the amount of rare earths, and more specifically HREs, major progress is seen in electrophoretic deposition as a method for accurately positioning the HRE on the surface prior to its diffusion into the microstructure. This locally increases the coercivity of the rather small Nd-Fe-B-type magnet, thereby substantially reducing the dependence on the HREs Dy and Tb, two of the most critical raw materials identified by the European Commission. Overall, the ROMEO project has demonstrated that rapid progress can be achieved when experts in a specific area are brought together to focus on a particular challenge. With more than half a year of the ROMEO project remaining, further progress and additional breakthroughs can be expected.

A fully pearlitic steel was deformed by high-pressure torsion up to very high strains, and the changes in the microstructure were determined by analytic and conventional transmission electron microscopy. The imposed strain leads to a fragmentation and an alignment of the cementite lamellae parallel to the shear plane. The electron energy-loss near-edge-fine structures of the Fe-L^sub 2,3^-edge of the iron matrix and the cementite lamellae were measured with high spatial resolution. The results indicated that after high-pressure torsion, the iron matrix contains finely dispersed carbon-rich areas that do not show the electronic fingerprint of cementite. However, the refinement in microstructure leads to an enormous increase in mechanical strength. [PUBLICATION ABSTRACT]