Many biologists assume, as Darwin did, that natural selection acts mainly on late embryonic or postnatal development. This view is consistent with von Baer's observations of morphological divergence at late stages. It is also suggested by the conserved morphology and common molecular genetic mechanisms of pattern formation seen in embryos. I argue here, however, that differences in adult morphology may be generated at a variety of stages. Natural selection may have a major action on developmental mechanisms during the organogenetic (...) period, because this is when many adult traits are specified. Evolutionary changes in these early developmental mechanisms probably include subtle shifts in the timing of gene expression. Changes of this kind have little or no gross effect on the anatomy of the embryo; they are only phenotypically expressed, or readily detected, when amplified at later stages. The phylotypic stage, the developmental hourglass, modularity, and von Baerian divergence are reassessed in terms of these arguments. BioEssays 21:604–613, 1999. © 1999 John Wiley & Sons, Inc. (shrink)

Objects are reminiscent of actions often performed with them: knife and apple remind us on peeling the apple or cutting it. Mnemonic representations of object-related actions (action codes) evoked by the sight of an object may constrain and hence facilitate recognition of unrolling actions. The present fMRI study investigated if and how action codes influence brain activation during action observation. The average number of action codes (NAC) of 51 sets of objects was rated by a group of n = 24 (...) participants. In an fMRI study, different volunteers were asked to recognize actions performed with the same objects presented in short videos. To disentangle areas reflecting the storage of action codes from those exploiting them, we showed object-compatible and object-incompatible (pantomime) actions. Areas storing action codes were considered to positively co-vary with NAC in both object-compatible and object-incompatible action; due to its role in tool-related tasks, we here hypothesized left anterior inferior parietal cortex (aIPL). In contrast, areas exploiting action codes were expected to show this correlation only in object-compatible but not incompatible action, as only object-compatible actions match one of the active action codes. For this interaction, we hypothesized ventrolateral premotor cortex (PMv) to join aIPL due to its role in biasing competition in IPL. We found left anterior intraparietal sulcus (IPS) and left posterior middle temporal gyrus (pMTG) to co-vary with NAC. In addition to these areas, action codes increased activity in object-compatible action in bilateral PMv, right IPS, and lateral occipital cortex (LO). Findings suggest that during action observation, the brain derives possible actions from perceived objects, and uses this information to shape action recognition. In particular, the number of expectable actions quantifies the activity level at PMv, IPL, and pMTG, but only PMv reflects their biased competition while observed action unfolds. (shrink)

© 2016 Regents of the University of California.The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous (...) tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 117 reviews are many that are new or heavily revised, including those on Pentaquarks and Inflation. The complete Review is published online in a journal and on the website of the Particle Data Group. The printed PDG Book contains the Summary Tables and all review articles but no longer includes the detailed tables from the Particle Listings. A Booklet with the Summary Tables and abbreviated versions of some of the review articles is also available. (shrink)

Early zoological researches by P.S. Pallas and K.E. von Baer in their letters to the zoologists of Berlin. The centenaries which are celebrated in 1991 and 1992 in memory of P.S. Pallas (1791) and K.E. von Baer (born 1792) caused the following studies of hitherto unpublished sources, preserved in the collections of the Museum für naturkunde in Berlin. The earliest zoological works of Pallas are discussed in relation to his last publication on the “Zoographia Rosso-Asiatica” which should have (...) been finished in Berlin. Some years after the death of Pallas, Baer also contacted the Berlin zoologists K.A. Rudolphi and M.H. Lichtenstein, asking for help, when he was going to establish zoology and a zoological museum at the University of Königsberg. (shrink)

Se editan los textos centrales de la conferencia pronunciada en 1860 por K. E. y. Baer, según la rara edición que hizo de la misma en ¡862. Su mostración imaginativa de lo diferente que sería nuestra representación de la realidad natural con el USO de otros cánones espacio-temporales, puede volver a interesar hoy, sobre todo, al llamado Constructivismo,Zentrale Texte des Vortrages von 1860, den It E. y. Baer lii Petesbrug hielt, nach der seltenen Ausgabe von 1862, sowie ibre (...) spanische Ubersetzung sind hier herausgegeben. Seine imaginative Darstellung der ganz verschiedenen Auffasung der Natur nach der Veránderung des Raum-Zeit-Mai3stabes gelten jinmer noch als Anregung ciner fruchtbaren Reflexion, tiberhaupt in Zeiten des sogenannten Konstruktivismus. (shrink)

Over the last two decades, semantic theory has been marked by a continuing shift from a static view of meaning to a dynamic one. The increasing interest in extending semantic analysis from isolated sentences to larger units of discourse has fostered the intensive study of anaphora and coreference, and this has engendered a shift from viewing meaning as truth conditions to viewing it as the potential to change the "informational context".

Background Health care workers (HCWs) are susceptible to moral stress and distress when they are faced with morally challenging situations where it is difficult to act in line with their moral standards. In times of crisis, such as disasters and pandemics, morally challenging situations are more frequent, due to the increased imbalance between patient needs and resources. However, the concepts of moral stress and distress vary and there is unclarity regarding the definitions used in the literature. This study aims to (...) map and analyze the descriptions used by HCWs regarding morally challenging situations (moral stress) and refine a definition through conceptual analysis. Methods Qualitative data were collected in a survey of 16,044 Swedish HCWs who attended a COVID-19 online course in autumn 2020. In total, 643 free-text answers with descriptions of moral stress were analyzed through content analysis. Results Three themes emerged from the content analysis (1) “Seeing, but being prevented to act; feeling insufficient/inadequate and constrained in the profession,” (2) “Someone or something hindered me; organizational structures as an obstacle,” and (3) “The pandemic hindered us; pandemic-related obstacles.” The three themes correspond to the main theme, “Being prevented from providing good care.” Discussion The main theme describes moral stress as various obstacles to providing good care to patients in need and acting upon empathic ability within the professional role. The themes are discussed in relation to established definitions of moral stress and are assessed through conceptual analysis. A definition of moral stress was refined, based on one of the established definitions. Conclusions On the basis of the study results and conceptual analysis, it is argued that the presented definition fulfils certain conditions of adequacy. It is essential to frame the concept of moral stress, which has been defined in different ways in different disciplines, in order to know what we are talking about and move forward in developing prevention measures for the negative outcomes of this phenomenon. (shrink)

Several lines of evidence suggest that children born via Cesarean section are at greater risk for adverse health outcomes including allergies, asthma and obesity. Vaginal seeding is a medical procedure in which infants born by C-section are swabbed immediately after birth with vaginal secretions from the mother. This procedure has been proposed as a way to transfer the mother's vaginal microbiome to the child, thereby restoring the natural exposure that occurs during vaginal birth that is interrupted in the case of (...) babies born via C-section. Preliminary evidence indicates partial restoration of microbes. However, there is insufficient evidence to determine the health benefits of the procedure. Several studies, including trial, are currently underway. At the same time, in the clinic setting, doctors are increasingly being asked to by expectant mothers to have their babies seeded. This article reports on the current research on this procedure and the issues it raises for regulators, researchers, physicians, and patients. (shrink)