ALBERT

Description: Corrigendum: Mapping tree density at a global scale Nature 532, 7598 (2016). doi:10.1038/nature16178 Authors: T. W. Crowther, H. B. Glick, K. R. Covey, C. Bettigole, D. S. Maynard, S. M. Thomas, J. R. Smith, G. Hintler, M. C. Duguid, G. Amatulli, M.-N. Tuanmu, W. Jetz, C. Salas, C. Stam, D. Piotto, R. Tavani, S. Green, G. Bruce, S. J. Williams, S. K. Wiser, M. O. Huber, G. M. Hengeveld, G.-J. Nabuurs, E. Tikhonova, P. Borchardt, C.-F. Li, L. W. Powrie, M. Fischer, A. Hemp, J. Homeier, P. Cho, A. C. Vibrans, P. M. Umunay, S. L. Piao, C. W. Rowe, M. S. Ashton, P. R. Crane & M. A. Bradford Nature525, 201–205 (2015); doi:10.1038/nature14967In the first boldface paragraph of this Article, the global number of trees should be approximately ‘1.30 trillion’ (rather than ‘1.39 trillion’) for tropical and subtropical forests and ‘0.66 trillion’ (rather than ‘0.61

Description: Extinct mid-ocean ridges record past plate boundary reorganizations, and identifying their locations is crucial to developing a better understanding of the drivers of plate tectonics and oceanic crustal accretion. Frequently, extinct ridges cannot be easily identified within existing geophysical data sets, and there are many controversial examples that are poorly constrained. We analyze the axial morphology and gravity signal of 29 well-constrained, global, large-scale extinct ridges that are digitized from global data sets, to describe their key characteristics. Additionally, the characteristics of a representative collection of active spreading centers are analyzed to review the present-day variation in the bathymetry and gravity signal of ridges in different tectonic settings such as backarc basin ridges, microplate ridges, and large-scale plate boundaries with varied spreading rates. Uncertain extinct ridge-like structures are evaluated in comparison with the signals of well-defined extinct ridges, and we assess whether their morphology and gravity signals are within the range seen at extinct (or active) ridges. There is significant variability in extinct ridge morphology; yet we find that the majority of well-defined extinct ridges have a trough form and a negative free-air gravity anomaly. We compile available data on the spreading characteristics of extinct ridges prior to cessation, such as their spreading rates and duration of spreading, and find significant differences between ridge subtypes and between oceans. Large-scale extinct mid-ocean ridges persist much longer than extinct microplate spreading ridges and extinct backarc basin spreading ridges before cessation. Extinct fragmented plate and microplate spreading centers have the highest pre-extinction spreading rates, and they have greater median relief at their axial segments, suggesting that different crustal accretion styles could lead to different morphology after spreading cessation. Backarc basin ridges have more pronounced relief when they have been active for longer before cessation, which supports theories of reduced magmatic supply as the basin width increases. Extinct ridges in the Atlantic Ocean have the lowest spreading rates prior to cessation and tend to persist for twice as long as those in the Pacific before extinction. There are a larger number of extinct ridges preserved within marginal basins than expected for their combined area; these ridges may relate to the complexity of the plate boundaries in these regions. Our review of a large number of controversial extinct ridge locations offers some insight into which proposed locations are more likely to have been former spreading centers, and our analysis further leads to the discovery of several previously unidentified structures in the south of the West Philippine Basin that likely represent extinct ridges and a possible extinct ridge in the western South Atlantic. We make available our global compilation of data and analyses of individual ridges in a global extinct ridge data set at the GPlates Portal webpage 1 .

Description: Author(s): B. R. Marks, P. A. DeYoung, J. K. Smith, T. Baumann, J. Brown, N. Frank, J. Hinnefeld, M. Hoffman, M. D. Jones, Z. Kohley, A. N. Kuchera, B. Luther, A. Spyrou, S. Stephenson, C. Sullivan, M. Thoennessen, N. Viscariello, and S. J. Williams The neutron-unbound nucleus Be 13 was populated with a nucleon exchange reaction from a 71 MeV/u secondary B 13 beam. The decay-energy spectrum was reconstructed using invariant mass spectroscopy based on Be 12 fragments in coincidence with neutrons. The data could be described with an s -wave resonance… [Phys. Rev. C 92, 054320] Published Mon Nov 23, 2015

Description: Author(s): R. Dunlop, G. C. Ball, J. R. Leslie, C. E. Svensson, I. S. Towner, C. Andreoiu, S. Chagnon-Lessard, A. Chester, D. S. Cross, P. Finlay, A. B. Garnsworthy, P. E. Garrett, J. Glister, G. Hackman, B. Hadinia, K. G. Leach, E. T. Rand, K. Starosta, E. R. Tardiff, S. Triambak, S. J. Williams, J. Wong, S. W. Yates, and E. F. Zganjar A high-precision branching-ratio measurement for the superallowed β + decay of 74 Rb was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electron-positron tagging array (SCEPTAR), composed of 10 thin plastic scintillators, was used to d... [Phys. Rev. C 88, 045501] Published Tue Oct 01, 2013

Description: Low concentrations (tens to hundreds of parts per million) of water in nominally anhydrous minerals (NAMs) of the mantle have been shown to significantly affect the rheology, depth of depressurization melting, and many other properties of the mantle. In this contribution, we evaluate the effect of trace concentrations of water in NAMs on melting of lower continental crust. Water locked in structural sites and in fluid inclusions in nominally anhydrous minerals in lower crustal granitoids may act as a flux for partial melting of these source rocks. Water concentrations of 3000 ppm in minerals that make up large volumes of crustal rocks (K-feldspar, plagioclase, quartz) would lower the dry solidus of granite by 273 °C at 1 GPa. Measurements and maps of water concentration in variably deformed samples of the Stevenson Granite from northern Saskatchewan (Canada) show that, during deformation and recrystallization of K-feldspar megacrysts, water migrated from the interior of megacrysts to finer-grained matrix material. Dark, fine-grained, water-richer matrix material consisting of quartz, plagioclase, alkali feldspar, and fine iron oxides are interpreted to be former melt films that resulted, at least in part, from fluxing by NAM-derived water. Deformation may play a role in moving water from NAMs to phase boundaries where generation of partial melt may lead to further rock weakening and further release of water from NAMs.

Description: We studied two groups of adult macaque monkeys to determine the time course of adult neurogenesis in the dentate gyrus of the hippocampus. In the first group, six adult monkeys (Macaca mulatta) received a single injection of the thymidine analog BrdU (75 mg/kg), which is incorporated into replicating DNA and serves as a marker for new cell birth. Brain tissue was collected 48 h, 2 wk, and 6 wk after BrdU injection to examine the initial stages of neurogenesis. Because mature neurons were not evident at 6 wk, we examined tissue collected over a longer time course in a second study. In this study, eight monkeys (Macaca fascicularis) who were subjects in a separate exercise study received 10 weekly injections of BrdU (75 mg/kg), and brain tissue was collected at 16 and 28 wk from the first injection. Based on the timing of expression of neuronal cell markers (βIII-tubulin, doublecortin, NeuN), the extent of dendritic arborization, and acquisition of mature cell body morphology, we show that granule cell maturation in the dentate gyrus of a nonhuman primate is protracted over a minimum of a 6-mo time period, more than 6 times longer than in rodents. The lengthened time course for new cell maturation in nonhuman primates may be appropriate for preservation of neural plasticity over their longer life span and is relevant to our understanding of antidepressant and other therapies that have been linked to neurogenesis in humans.

Description: The Mississippian Strathclyde Group of the Midland Valley of Scotland yields some of the earliest non-marine ostracods. The succession records shallow marine, deltaic, estuarine, lagoonal, lacustrine, fluvial and swamp environments representing a series of staging-posts between fully marine and limnetic settings. Macrofossils and ostracods are assigned to marine, marginal marine, brackish and freshwater environments based on their faunal assemblage patterns. Key brackish to freshwater ostracods are Geisina arcuata, Paraparchites circularis n. sp., Shemonaella ornata n. sp. and Silenites sp. A, associated with the bivalves Anthraconaia, Carbonicola, Cardiopteridium, Curvirimula, Naiadites, the microconchid ‘Spirorbis’, Spinicaudata and fish. Many Platycopina and Paraparchiticopina ostracods are interpreted as euryhaline, which corresponds with their occurrence in marine to coastal plain water bodies, and supports the ‘estuary effect’ hypothesis of non-marine colonization. The success of non-marine colonization by ostracods was dependent on the intrinsic adaptations of ostracod species to lower salinities, such as new reproductive strategies and the timing of extrinsic mechanisms to drive non-marine colonization, such as sea-level change. The genus Carbonita is the oldest and most common freshwater ostracod, and went on to dominate freshwater environments in the Late Palaeozoic.

Description: Explanations for women's underrepresentation in math-intensive fields of science often focus on sex discrimination in grant and manuscript reviewing, interviewing, and hiring. Claims that women scientists suffer discrimination in these arenas rest on a set of studies undergirding policies and programs aimed at remediation. More recent and robust empiricism, however, fails to support assertions of discrimination in these domains. To better understand women's underrepresentation in math-intensive fields and its causes, we reprise claims of discrimination and their evidentiary bases. Based on a review of the past 20 y of data, we suggest that some of these claims are no longer valid and, if uncritically accepted as current causes of women's lack of progress, can delay or prevent understanding of contemporary determinants of women's underrepresentation. We conclude that differential gendered outcomes in the real world result from differences in resources attributable to choices, whether free or constrained, and that such choices could be influenced and better informed through education if resources were so directed. Thus, the ongoing focus on sex discrimination in reviewing, interviewing, and hiring represents costly, misplaced effort: Society is engaged in the present in solving problems of the past, rather than in addressing meaningful limitations deterring women's participation in science, technology, engineering, and mathematics careers today. Addressing today's causes of underrepresentation requires focusing on education and policy changes that will make institutions responsive to differing biological realities of the sexes. Finally, we suggest potential avenues of intervention to increase gender fairness that accord with current, as opposed to historical, findings.

Description: Author(s): P. Finlay, S. Ettenauer, G. C. Ball, J. R. Leslie, C. E. Svensson, C. Andreoiu, R. A. E. Austin, D. Bandyopadhyay, D. S. Cross, G. Demand, M. Djongolov, P. E. Garrett, K. L. Green, G. F. Grinyer, G. Hackman, K. G. Leach, C. J. Pearson, A. A. Phillips, C. S. Sumithrarachchi, S. Triambak, and S. J Williams A high-precision half-life measurement for the superallowed β^{+} emitter ^{26} Al ^{m} was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T_{1/2} =6346.54±0.46_{stat} ±0.60_{syst}   ms, consistent with, but 2.5 times more precise than, the previous world average. The ^{2... [Phys. Rev. Lett. 106, 032501] Published Fri Jan 21, 2011

Description: Drago (1) makes a number of good points about the need to consider historical trends and culture in understanding women's underrepresentation in math-intensive fields. We agree with some of these points and have no position on others. Nevertheless, we want to point out that the main point—that we should consider historical and cultural influences in sex segregation—is something that we have done consistently in our publications on this topic, including this one (2–4). In online SI Text accompanying our article, we reiterated a point we have made in numerous past articles, namely, that sex cannot be considered in isolation from...