Halcyornis toliapicus (aves: Lower Eocene, England) indicates advanced neuromorphology in Mesozoic Neornithes

Our recent X-ray micro computer-tomographic (μCT) investigations of Prophaethon shrubsolei and Odontopteryx toliapica from the Lower Eocene London Clay Formation of England revealed the avian brain to have been essentially modern in form by 55 Ma, but that an important vision-related synapomorphy of living birds, the eminentia sagittalis of the telencephalon, was poorly developed. This evidence suggested that the feature probably appeared close to the end of the Mesozoic. Here we use μCT analysis to describe the endocranium of Halcyornis toliapicus, also from the London Clay Formation. The affinities of Halcyornis have been hotly debated, with the taxon referred to the Charadriiformes (Laridae), Coraciiformes (Alcedinidae, and its own family Halcyornithidae) and most recently that Halcyornithidae may be a possible senior synonym of Pseudasturidae (Pan-Psittaciformes). Unlike Prophaethon and Odontopteryx, the eminentia sagittalis of Halcyornis is strongly developed and comparable to that of living species. Like those London Clay taxa, the eminentia sagittalis occupies a rostral position on the telencephalon. The senses of Halcyornis appear to have been well developed. The length of the cochlear duct of the inner ear indicates a hearing sensitivity within the upper range of living species, and enlarged olfactory lobes suggest a reasonable reliance on sense of smell. The optic nerves were especially well developed which, together with the strong development of the eminentia sagittalis, indicates a high degree of visual specialization in Halcyornis. The advanced development of the eminentia sagittalis further supports a Mesozoic age for the appearance of this structure and associated neural architectural complexity found in extant Aves. The eminentia sagittalis of living Psittaciformes is situated caudally on the telencephalon, making a Pan-Psittaciformes relationship unlikely for Halcyorni

Catastrophic drought in the Afro-Asian monsoon region during Heinrich Event 1

Between 18,000 and 15,000 years ago, large amounts of ice and meltwater entered the North Atlantic during Heinrich Stadial 1. This caused substantial regional cooling, but major climatic impacts also occurred in the tropics. Here we demonstrate that the height of this stadial, ca. 17-16,000 years ago ("Heinrich Event 1"), coincided with one of the most extreme and widespread megadroughts of the last 50,000 years or more in the Afro-Asian monsoon region, with potentially serious consequences for Paleolithic cultures. Late Quaternary tropical drying commonly is attributed to southward drift of the Intertropical Convergence Zone, but the broad geographic range of the H1 Megadrought suggests that severe, systemic weakening of Afro-Asian rainfall systems also occurred, probably in response to sea surface cooling

Origin of complex crystal structures of elements at pressure

We present a unifying theory for the observed complex structures of the sp-bonded elements under pressure based on nearly free electron picture (NFE). In the intermediate pressure regime the dominant contribution to crystal structure arises from Fermi-surface Brillouin zone (FSBZ) interactions - structures which allow this are favoured. This simple theory explains the observed crystal structures, transport properties, the evolution of internal and unit cell parameters with pressure. We illustrate it with experimental data for these elements and ab initio calculation for Li.Comment: 4 pages 5 figure

Head Depth and Head Speed During Competitive Backstroke Ledge Starts

Recently, a commercially available starting ‘ledge’ designed to reduce foot slippage during the execution of the backstroke start was introduced in competitive swimming. For the purpose of identifying potential safety consequences, the present study investigated the effect of ledge use on head depths, speeds, and distances in backstroke starts of athletes with no prior or only novice familiarity of the ledge. Competitive backstroke starts were performed with and without ledges by high school-aged (14.5 to 19.2 yr, N = 61) swimmers in 1.52 m of water during a closed testing session. A SIMI Reality Motion System in a calibrated space using three cameras was employed for filming starts. Dependent measures were initial head height (Yset), distance from wall at entry (Xentry), entry angle (Angleentry), horizontal velocity at head entry (XVelentry), resultant velocity at entry (ResVelentry), maximum depth of the center of the head (Ymhd), resultant velocity at maximum head depth (ResVelmhd), and distance from the wall at maximum head depth (Xmhd). The ledge (L) condition showed significant increases compared to the non-ledge (NL) condition in Xentry (L 1.61 ± 0.59 m, NL 1.50 ± 0.53 m, p \u3c .001), ResVelentry (L 3.44 ± 0.97 m·s-1, NL 3.08 ± 1.00 m·s-1, p \u3c .001), Angleentry (L 43.13 ± 16.97°, NL 39.66 ± 18.11°, p = .030), Xmhd (L 4.18 ± 0.58 m, NL 4.09 ± 0.63 m, p = .008), and Ymhd (L 0.54 ± 0.21 m, NL 0.49 ± 0.18,

Static Critical Behavior of the Spin-Freezing Transition in the Geometrically Frustrated Pyrochlore Antiferromagnet Y2Mo2O7

Some frustrated pyrochlore antiferromagnets, such as Y2Mo2O7, show a spin-freezing transition and magnetic irreversibilities below a temperature Tf similar to what is observed nonlinear magnetization measurements on Y2Mo2O7 that provide strong evidence that there is an underlying thermodynamic phase transition at Tf, which is characterized by critical exponents \gamma \approx 2.8 and \beta \approx 0.8. These values are typical of those found in random spin glasses, despite the fact that the level of random disorder in Y2Mo2O7 is immeasurably small.Comment: Latex file, calls for 4 encapsulated postscript figures (included). Submitted to Phys. Rev. Letters

Nuclear Magnetic Resonance and Hyperfine Structure

Contains research objectives and reports onAlfred P. Sloan Foundatio

Western Indian Ocean marine and terrestrial records of climate variability: a review and new concepts on land-ocean interactions since AD 1660

We examine the relationship between three tropical and two subtropical western Indian Ocean coral oxygen isotope time series to surface air temperatures (SAT) and rainfall over India, tropical East Africa and southeast Africa. We review established relationships, provide new concepts with regard to distinct rainfall seasons, and mean annual temperatures. Tropical corals are coherent with SAT over western India and East Africa at interannual and multidecadal periodicities. The subtropical corals correlate with Southeast African SAT at periodicities of 16–30 years. The relationship between the coral records and land rainfall is more complex. Running correlations suggest varying strength of interannual teleconnections between the tropical coral oxygen isotope records and rainfall over equatorial East Africa. The relationship with rainfall over India changed in the 1970s. The subtropical oxygen isotope records are coherent with South African rainfall at interdecadal periodicities. Paleoclimatological reconstructions of land rainfall and SAT reveal that the inferred relationships generally hold during the last 350 years. Thus, the Indian Ocean corals prove invaluable for investigating land–ocean interactions during past centuries

Building Irish families through surrogacy: medical and judicial issues for the advanced reproductive technologies

Surrogacy involves one woman (surrogate mother) carrying a child for another person/s (commissioning person/couple), based on a mutual agreement requiring the child to be handed over to the commissioning person/couple following birth. Reasons for seeking surrogacy include situations where a woman has non-functional or absent reproductive organs, or as a remedy for recurrent pregnancy loss. Additionally, surrogacy may find application in any medical context where pregnancy is contraindicated, or where a couple consisting of two males seek to become parents through oocyte donation. Gestational surrogacy is one of the main issues at the forefront of bioethics and the advanced reproductive technologies, representing an important challenge to medical law. This analysis reviews the history of surrogacy and clinical and legal issues pertaining to this branch of reproductive medicine. Interestingly, the Medical Council of Ireland does not acknowledge surrogacy in its current practice guidelines, nor is there specific legislation addressing surrogacy in Ireland at present. We therefore have developed a contract-based model for surrogacy in which, courts in Ireland may consider when confronted with a surrogacy dispute, and formulated a system to resolve any potential dispute arising from a surrogacy arrangement. While the 2005 report by the Commission on Assisted Human Reproduction (CAHR) is an expert opinion guiding the Oireachtas' development of specific legislation governing assisted human reproduction and surrogacy, our report represents independent scholarship on the contractual elements of surrogacy with particular focus on how Irish courts might decide on surrogacy matters in a modern day Ireland. This joint medico-legal collaborative also reviews the contract for services arrangement between the commissioning person/s and the surrogate, and the extent to which the contract may be enforced

Far-infrared optical properties of BI2SR2CACU2O8

The reflectance of crystals of Bi2Sr2 CaCu2O8 has been measured in the far-infrared region at 100 K in the normal state and at 1.5 K in the superconducting state. The normal-state properties are dominated at low frequency by a narrow Drude-like peak in the real part of the optical conductivity. At higher frequency there is substantial absorption above this Drude absorption that can be parametrized with two broad oscillators centered at roughly 400 and 1000 cm(-1) in the optical conductivity. In the superconducting state, there is a sharp reflectance edge at 300 cm(-1) associated with a threshold in the real part of the optical conductivity, but it is not certain that this is a conventional energy gap

Full lifetime perspectives on the costs and benefits of lay date variation in tree swallows

Animals must balance various costs and benefits when deciding when to breed. The costs and benefits of breeding at different times have received much attention, but most studies have been limited to investigating short-term season-to-season fitness effects. However, breeding early, versus late, in a season may influence lifetime fitness over many years, trading off in complex ways across the breeder?s lifepan. In this study, we examined the complete life histories of 867 female tree swallows (Tachycineta bicolor) breeding in Ithaca, New York, between 2002 and 2016. Earlier breeders outperformed later breeders in short-term measures of reproductive output and offspring quality. Though there were weak indications that females paid long-term future survival costs for breeding early, lifetime fledgling output was markedly higher overall in early-breeding birds. Importantly, older females breeding later in the season did not experience compensating life-history advantages that suggested an alternative equal-fitness breeding strategy. Rather, most or all of the swallows appear to be breeding as early as they can, and differences in lay dates appear to be determined primarily by differences in individual quality or condition. Lay date had a significant repeatability across breeding attempts by the same female, and the first lay date of females fledged in our population was strongly influenced by the first lay date of their mothers, indicating the potential for ongoing selection on lay date. By examining performance over the entire lifespan of a large number of individuals, we were able to clarify the relationship between timing of breeding and fitness and gain new insight into the sources of variability in this important life history trait.Fil: Winkler, David Ward. Cornell University; Estados UnidosFil: Hallinger, Kelly K.. Cornell University; Estados UnidosFil: Pegan, Teresa M.. University of Michigan; Estados UnidosFil: Taff, Conor C.. Cornell University; Estados UnidosFil: Verhoeven, Mo A.. University of Groningen; Países BajosFil: Van Oordt, David Chang. Cornell University; Estados UnidosFil: Stager, Maria. University of Montana; Estados UnidosFil: Uehling, Jennifer J.. Cornell University; Estados UnidosFil: Vitousek, Maren N.. Cornell University; Estados UnidosFil: Andersen, Michael J.. University of New Mexico; Estados UnidosFil: Ardia, Daniel R.. Franklin & Marshall College; Estados UnidosFil: Belmaker, Amos. Tel Aviv University; IsraelFil: Ferretti, Valentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Forsman, Anna M.. University Of Central Florida; Estados UnidosFil: Gaul, Jennifer R.. International High School at La Guardia Community College; Estados UnidosFil: Llambias, Paulo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Orzechowski, Sophia C.. Harvard University; Estados UnidosFil: Shipley, Ryan. Max Planck Institute For Animal Behavior; AlemaniaFil: Wilson, Maya. Virginia Polytechnic Institute. Department Of Geological Sciences; Estados UnidosFil: Yoon, Hyun Seok. University of Tennessee; Estados Unido