Proceedings of the Natural Academy of Sciences

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  • Measuring constraints on human life histories [Population Biology]
    [Jul 2015]

    Human life histories combine late age at first reproduction, long reproductive span, relatively high fertility, and substantial postreproductive survival. However, even among the most fecund populations, human fertility falls far below its theoretical maximum. The extent of parental care required for successful offspring recruitment and widespread fertility decline under proper...
    Categories: Journal Articles
  • Statistical universals of human music [Psychological and Cognitive Sciences]
    [Jul 2015]

    Music has been called “the universal language of mankind.” Although contemporary theories of music evolution often invoke various musical universals, the existence of such universals has been disputed for decades and has never been empirically demonstrated. Here we combine a music-classification scheme with statistical analyses, including phylogenetic comparative methods, to...
    Categories: Journal Articles
  • Intergenerational mediators of anxious temperament [Psychological and Cognitive Sciences]
    [Jul 2015]

    Understanding the heritability of neural systems linked to psychopathology is not sufficient to implicate them as intergenerational neural mediators. By closely examining how individual differences in neural phenotypes and psychopathology cosegregate as they fall through the family tree, we can identify the brain systems that underlie the parent-to-child transmission of...
    Categories: Journal Articles
  • Twentieth century surge of excess male mortality [Social Sciences]
    [Jul 2015]

    Using historical data from 1,763 birth cohorts from 1800 to 1935 in 13 developed countries, we show that what is now seen as normal—a large excess of female life expectancy in adulthood—is a demographic phenomenon that emerged among people born in the late 1800s. We show that excess adult male...
    Categories: Journal Articles
  • In This Issue [This Week in PNAS]
    [Jul 2015]

    Evaluating household-based interventions against influenza Hong Kong’s high urban population density provides an ideal breeding ground for influenza. Image courtesy of Kenneth Chung (photographer). Household-based interventions such as increased hand hygiene and face masks are crucial for combating influenza. The efficacy of such interventions is traditionally assessed by measuring their...
    Categories: Journal Articles
  • microRNAs and inherited retinal dystrophies [Genetics]
    [Jul 2015]

    Inherited retinal dystrophies (IRD) are a heterogeneous group of blinding diseases that affect more than 200,000 Americans and millions worldwide (1). Identification of genes that are responsible for IRD when defective is of great importance to the basic understanding as well as development of efficient gene diagnosis and treatment. Thus...
    Categories: Journal Articles
  • Partial account of adolescent impulsivity [Psychological and Cognitive Sciences]
    [Jul 2015]

    Adults have been concerned about adolescent impetuosity for centuries. The rashness of youth has been blamed for many teenage indiscretions, from juvenile delinquency to unprotected sex and substance use. At the turn of the 21st century, research on the development of self-control in adolescence added functional brain imaging as a...
    Categories: Journal Articles
  • Music across cultures [Anthropology]
    [Jul 2015]

    Singing, rhythmic movement to music, and musical instruments, blown or struck, are pervasive, with a deep history (1). Ethnomusicologists do not dispute the existence of core abilities that support a variety of musical activities across cultures, but they are generally averse to notions of universals involving musical structure or form...
    Categories: Journal Articles
  • CRY signaling does not require the Trp triad [Plant Biology]
    [Jul 2015]

    For over 100 years it has been known that a blue light photoreceptor regulates growth and development in plants under low-light conditions. These photoreceptors were termed cryptochomes (CRYs) because of their importance in cryptogamic plants and the cryptic aspects of their function and photochemistry (1, 2). Despite decades of progress...
    Categories: Journal Articles
  • Clonal reproduction: Alternatives to sex [Introductions]
    [Jul 2015]

    Evolutionary studies of clonal organisms have advanced considerably in recent years, but are still fledgling. Although recent textbooks on evolution or genetics might give the impression that nonsexual reproduction is an anomaly in the living world, clonality is the rule rather than the exception in many viruses, bacteria, and parasites...
    Categories: Journal Articles
  • Statistical energy conservation principle [Applied Mathematics]
    [Jul 2015]

    Understanding the complexity of anisotropic turbulent processes over a wide range of spatiotemporal scales in engineering shear turbulence as well as climate atmosphere ocean science is a grand challenge of contemporary science with important societal impact. In such inhomogeneous turbulent dynamical systems there is a large dimensional phase space with...
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  • Graphene microphone and ultrasonic radio [Applied Physical Sciences]
    [Jul 2015]

    We present a graphene-based wideband microphone and a related ultrasonic radio that can be used for wireless communication. It is shown that graphene-based acoustic transmitters and receivers have a wide bandwidth, from the audible region (20∼20 kHz) to the ultrasonic region (20 kHz to at least 0.5 MHz). Using the...
    Categories: Journal Articles
  • Intrinsic (un)foldase activity of GroEL [Biophysics and Computational Biology]
    [Jul 2015]

    The prototypical chaperonin GroEL assists protein folding through an ATP-dependent encapsulation mechanism. The details of how GroEL folds proteins remain elusive, particularly because encapsulation is not an absolute requirement for successful re/folding. Here we make use of a metastable model protein substrate, comprising a triple mutant of Fyn SH3, to...
    Categories: Journal Articles
  • Artificial cloning of domestic animals [Colloquium Paper]
    [Jul 2015]

    Domestic animals can be cloned using techniques such as embryo splitting and nuclear transfer to produce genetically identical individuals. Although embryo splitting is limited to the production of only a few identical individuals, nuclear transfer of donor nuclei into recipient oocytes, whose own nuclear DNA has been removed, can result...
    Categories: Journal Articles
  • Sex is an old, inherent attribute of eukaryotes [Colloquium Paper]
    [Jul 2015]

    Sexual reproduction and clonality in eukaryotes are mostly seen as exclusive, the latter being rather exceptional. This view might be biased by focusing almost exclusively on metazoans. We analyze and discuss reproduction in the context of extant eukaryotic diversity, paying special attention to protists. We present results of phylogenetically extended...
    Categories: Journal Articles
  • Clonal evolutionary processes in cancer [Colloquium Paper]
    [Jul 2015]

    Clonal evolutionary processes can drive pathogenesis in human diseases, with cancer being a prominent example. To prevent or treat cancer, mechanisms that can potentially interfere with clonal evolutionary processes need to be understood better. Mathematical modeling is an important research tool that plays an ever-increasing role in cancer research. This...
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  • Asexual invaders and the costs of sex [Colloquium Paper]
    [Jul 2015]

    The high prevalence of sexual reproduction is considered a paradox mainly for two reasons. First, asexuals should enjoy various growth benefits because they seemingly rid themselves of the many inefficiencies of sexual reproduction—the so-called costs of sex. Second, there seems to be no lack of asexual origins because losses of...
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  • Clonality and plant sexual reproduction [Colloquium Paper]
    [Jul 2015]

    Flowering plants possess an unrivaled diversity of mechanisms for achieving sexual and asexual reproduction, often simultaneously. The commonest type of asexual reproduction is clonal growth (vegetative propagation) in which parental genotypes (genets) produce vegetative modules (ramets) that are capable of independent growth, reproduction, and often dispersal. Clonal growth leads to...
    Categories: Journal Articles
  • Clonal reproduction in vertebrate animals [Colloquium Paper]
    [Jul 2015]

    A synopsis is provided of different expressions of whole-animal vertebrate clonality (asexual organismal-level reproduction), both in the laboratory and in nature. For vertebrate taxa, such clonal phenomena include the following: human-mediated cloning via artificial nuclear transfer; intergenerational clonality in nature via parthenogenesis and gynogenesis; intergenerational hemiclonality via hybridogenesis and kleptogenesis;...
    Categories: Journal Articles
  • Genetic therapy and cloning [Colloquium Paper]
    [Jul 2015]

    There are, in mankind, two kinds of heredity: biological and cultural. Cultural inheritance makes possible for humans what no other organism can accomplish: the cumulative transmission of experience from generation to generation. In turn, cultural inheritance leads to cultural evolution, the prevailing mode of human adaptation. For the last few...
    Categories: Journal Articles