Two new Miocene limpets (Fissurellidae) from southern California, with notes on other fossil occurrences of the family in northwestern North America

Two new fissurellid limpets (Mollusca: Gastropoda: Fissurellidae), Fissurella? stantoni n. sp. and Scelidotoma aldersoni n. sp., are described from Miocene deposits in southern California. Fissurella? stantoni is described from a single specimen from the middle Miocene Topanga Canyon Formation in the Santa Monica Mountains, Los Angeles County, California. Scelidotoma aldersoni is described from two specimens, one from the middle Miocene Topanga Canyon Formation, and another provisionally (cf.) identified specimen of an internal mold from the middle Miocene “Vaqueros” Formation on Santa Cruz Island, Santa Barbara County, southern California. Other unreported fossil occurrences of Scelidotoma are a juvenile specimen attributed only to genus collected in the middle Eocene Crescent Formation in Washington state and S. bella from the Pliocene part of the San Diego Formation, San Diego County, California. The Scelidotoma occurrences extend the chronostratigraphic range of S. bella from the Holocene (living) to the middle Pliocene, and the range of the genus back to the middle Eocene

The Park City Consolidated Mine Madison County, Missouri

The purpose of this study is the application of the principles of mining geology to a search for additional ore in one of Missouri\u27s lead mines and to provide in the literature a general analysis of the type of lead deposit found in Southeast Missouri whereby future prospecting and development work on similar deposits may be more efficiently carried on. The study consists of a thorough consideration of the geology and operation of the mine being worked by the Park City Consolidated Mines Company, Missouri Division, at Fredericktown, Madison County, Missouri. The field work was conducted during the months of June and July 1947. This included a Brunton and tape traverse of the mine workings and a thorough familiarization with the mine workings and a thorough familiarization with the mining method --Introduction, page 1

Micro- and nano-size hydrogrossular-like clusters in pyrope crystals from ultra-high-pressure rocks of the Dora-Maira Massif, western Alps

The supracrustal metamorphic rocks of the Dora-Maira Massif, western Alps, have been intensively studied. Certain ultra-high-pressure lithologies contain coesite and nearly end-member composition pyrope, Mg₃Al₂Si₃O₁₂, making this locality petrologically and mineralogically unique. Structural OH⁻, loosely termed “water”, in pyrope crystals of different composition has been investigated numerous times, using different experimental techniques, by various researchers. However, it is not clear where the minor OH⁻ is located in them. IR single-crystal spectra of two pyropes of composition {Mg_(2.79),Fe²⁺_(0.15),Ca_(0.04)}_(Σ2.98)[Al]_(2.02)(Si)_(2.99)O₁₂ and {Mg_(2.90),Fe²⁺_(0.04),Ca_(0.02)}_(Σ2.96)[Al]_(2.03)(Si)₃O₁₂ were recorded at room temperature (RT) and 80 K. The spectra show five distinct OH⁻ bands located above 3600 cm⁻¹ at RT and seven narrow bands at 80 K and additional fine structure. The spectra were curve fit and the OH⁻ stretching modes analyzed and assigned. It is argued that OH⁻ is located in microscopic- and nano-size Ca₃Al₂H₁₂O₁₂-like clusters. The basic substitution mechanism is the hydrogarnet one, where (H₄O₄)⁴⁻ ⇔ (SiO₄)⁴⁻, and various local configurations containing different numbers of (H₄O₄)⁴⁻ groups define the cluster type. The amounts of H₂O range between 5 and 100 ppm by weight, depending on the IR calibration adopted, and are variable among crystals. Hydrogrossular-like clusters are also present in a synthetic pyrope with a minor Ca content grown hydrothermally at 900 °C and 20 kbar, as based on its IR spectra at RT and 80 K. Experiment and nature are in agreement, and OH⁻ groups are partitioned into various barely nano-size hydrogrossular-like clusters. This proposal is new and significant mineralogical, petrological, and geochemical implications result. Ca and proton ordering occur. Hypothetical “defect” and/or coupled-substitution mechanisms to account for structural OH⁻ are not needed to interpret experimental results. OH⁻ incorporation in pyrope of different generations at Dora-Maira is discussed and OH- could potentially be used as an indicator of changing P_(H₂O)(a_(H₂O)) – T conditions in a metamorphic cycle. Published experimental hydration, dehydroxylation, and hydrogen diffusion results on Dora-Maira pyropes can now be interpreted atomistically

Heat capacity and entropy behavior of andradite: a multi-sample and −methodological investigation

Andradite, ideal end-member formula Ca_3 Fe^(3+)_2Si_3O_(12), is one of the common rock-forming garnets found in the Earth's crust. There are several outstanding questions regarding andradite's thermodynamic and physical property behavior. Three issues are: i) Could there be differences in the thermodynamic properties, namely heat capacity, C_p , between synthetic and natural andradite crystals, as observed in the Ca-garnet grossular, Ca_3Al_2Si_3O_(12)? ii) What is the thermal nature of the low-temperature magnetic-phasetransition behavior of andradite? and iii) How quantitative are older published calorimetric (i. e., adiabatic and DSC) heat-capacity results? In this work, four natural nearly end-member single crystals and two synthetic polycrystalline andradite samples were carefully characterized by optical microscope examination, X-ray powder diffraction, microprobe analysis, and IR and UV/VIS single-crystal spectroscopy. The IR spectra of the different samples commonly show a main intense OH stretching band located at 3563 cm^(-1), but other OH bands can sometimes be observed as well. Structural OH concentrations, calculated from the IR spectra, vary from about 0.006 to 0.240 wt% H_2O. The UV/VIS spectra indicate that there can be slight, but not fully understood, differences in the electronic state between synthetic and natural andradite crystals. The C_p behavior was determined by relaxation calorimetry between 2 and 300 K and by differential scanning calorimetry (DSC) methods between 150/300 and 700/950 K, employing the same andradite samples that were used for the other characterization measurements. The low-temperature C_p results show a magnetic phase transition with a Néel temperature of 11.3 ± 0.2 K, which could be slightly affected by the precise electronic state of Fe^(2+/3+) in the crystals. The published adiabatic calorimetry results on andradite do not provide a full and correct thermal description of this magnetic transition. The calorimetric Cp measurements give a best estimate for the standard third-law entropy at 298.15 K for andradite of S^o ≈ 324 ± 2 J/mol · K vs. the value of 316.4 ± 2.0 J/mol · K, as given in an early adiabatic investigation. Both natural and synthetic crystals give similar S o values within experimental uncertainty of about 1.0%, but one natural andradite, richer in OH, may have a very slightly higher value around S^o≈ 326 J/mol·K. Low-temperature DSC measurements made below 298 K agree excellently with those from relaxation calorimetry. The DSC measurements above 298 K show a similarity in C_p behavior among natural and synthetic andradites. A C_p polynomial for use above room temperature to approximately 1000 K was calculated from the data on synthetic andradite giving: C_p (J/mol·K) = 599.09 (±14) 2709.5 (±480)· T^(0.5) 1.3866 (±0.26)· 10^7 · T^2 + 1.6052 (±0.42) · 10^9 · T^3

Vinculin controls focal adhesion formation by direct interactions with talin and actin

Focal adhesions (FAs) regulate cell migration. Vinculin, with its many potential binding partners, can interconnect signals in FAs. Despite the well-characterized structure of vinculin, the molecular mechanisms underlying its action have remained unclear. Here, using vinculin mutants, we separate the vinculin head and tail regions into distinct functional domains. We show that the vinculin head regulates integrin dynamics and clustering and the tail regulates the link to the mechanotransduction force machinery. The expression of vinculin constructs with unmasked binding sites in the head and tail regions induces dramatic FA growth, which is mediated by their direct interaction with talin. This interaction leads to clustering of activated integrin and an increase in integrin residency time in FAs. Surprisingly, paxillin recruitment, induced by active vinculin constructs, occurs independently of its potential binding site in the vinculin tail. The vinculin tail, however, is responsible for the functional link of FAs to the actin cytoskeleton. We propose a new model that explains how vinculin orchestrates FAs

IR spectroscopy and OH^– in silicate garnet: The long quest to document the hydrogarnet substitution

There has been much research undertaken on structural OH^– in various nominally anhydrous minerals including the common silicate garnets (i.e., X_3Y_2Si_3O_(12), where X = Mg, Fe^(2+), Mn^(2+), and Ca and Y = Al, Fe^(3+), and Cr^(3+)). However, it is still largely not understood where small concentrations of H atoms are incorporated in the garnet crystal structure. In this work, the IR single-crystal spectra of end-member or approaching end-member composition andradite, pyrope, and almandine are measured. Both a natural and synthetic andradite sample show a broad, asymmetric OH^–-stretching mode at 3563 cm^(–1) that splits into two narrower modes at lower temperatures. They are located at 3575 and 3557 cm^(–1) at 80 K with the higher wavenumber mode being considerably more intense compared to that at lower energy. These results are analyzed together with published IR spectra of synthetic end-member katoite, pyrope, and almandine also recorded at low temperature. These garnets show similar IR behavior with a broad OH^– band at room temperature that splits into two narrower bands at lower temperatures and with a similar intensity relationship as shown by andradite. This behavior is indicative of the hydrogarnet substitution. The measured IR spectra of natural almandine- and pyrope-rich (Dora Maira, Italy) crystals, on the other hand, show different spectroscopic features with several OH^– modes that are not consistent with the hydrogarnet mechanism. An analysis of the energy of the OH^–-stretching mode is made for various composition hydrogarnet clusters [i.e., X_3Y_2(O_4H_4)_3, where X = Mg, Fe^(2+), Mn^(2+) and Ca and Y = Al and Fe^(3+)] in terms of crystal-chemical properties and local atomic configurations. The OH^– mode energy, which lies roughly between 3660 and 3550 cm^(–1) at RT for various end-member garnets, is a function of the mass of the X- and Y-cations due to mode coupling and/or mixing. In addition, the strength of the chemical bonding between the X- and Y-cations and the O^2–anion of the OH^– dipole plays a role in affecting the wavenumber of the OH^–-stretching vibration. OH^– mode broadening, observed in the spectra of end-member garnets, is primarily a result of thermal anharmonic disorder, especially with regard to the light H cation. OH mode broadening in intermediate solid-solution composition garnets is a function of both thermal effects and variations in local cation configurations around the OH^– dipole(s). Published IR spectra of certain high-pressure pyrope-rich garnets, both synthetic and natural, are analyzed and arguments made that OH^– can often be incorporated as the hydrogarnet or hydropyrope substitution. IR spectra similar in appearance, having multiple relatively narrow OH^– modes that are distinct from those indicating the hydrogarnet substitution, can be observed for certain synthetic end-member and various composition natural pyropes from Dora Maira and some natural spessartines. This indicates that other common OH^– substitution mechanisms, which have yet to be determined, can also occur in different silicate garnets

Anomalously High Recruitment of the 2010 Gulf Menhaden (Brevoortia patronus) Year Class: Evidence of Indirect Effects from the Deepwater Horizon Blowout in the Gulf of Mexico

Gulf menhaden (Brevoortia patronus) exhibited unprecedented juvenile recruitment in 2010 during the year of the Deepwater Horizon well blowout, exceeding the prior 39-year mean by more than four standard deviations near the Mississippi River. Abundance of that cohort remained exceptionally high for two subsequent years as recruits moved into older age classes. Such changes in this dominant forage fish population can be most parsimoniously explained as consequences of release from predation. Contact with crude oil induced high mortality of piscivorous seabirds, bottlenose dolphin (Tursiops truncatus), waders, and other fish-eating marsh birds, all of which are substantial consumers of Gulf menhaden. Diversions of fresh water from the Mississippi River to protect coastal marshes from oiling depressed salinities, impairing access to juvenile Gulf menhaden by aquatic predators that avoid low-salinity estuarine waters. These releases from predation led to an increase of Gulf menhaden biomass in 2011 to 2.4 million t, or more than twice the average biomass of 1.1 million t for the decade prior to 2010. Biomass increases of this magnitude in a major forage fish species suggest additional trophically linked effects at the population-, trophic-level and ecosystem scales, reflecting an heretofore little appreciated indirect effect that may be associated with major oil spills in highly productive marine waters

Heat capacity and entropy behavior of andradite: a multi-sample and −methodological investigation

Andradite, ideal end-member formula Ca_3 Fe^(3+)_2Si_3O_(12), is one of the common rock-forming garnets found in the Earth's crust. There are several outstanding questions regarding andradite's thermodynamic and physical property behavior. Three issues are: i) Could there be differences in the thermodynamic properties, namely heat capacity, C_p , between synthetic and natural andradite crystals, as observed in the Ca-garnet grossular, Ca_3Al_2Si_3O_(12)? ii) What is the thermal nature of the low-temperature magnetic-phasetransition behavior of andradite? and iii) How quantitative are older published calorimetric (i. e., adiabatic and DSC) heat-capacity results? In this work, four natural nearly end-member single crystals and two synthetic polycrystalline andradite samples were carefully characterized by optical microscope examination, X-ray powder diffraction, microprobe analysis, and IR and UV/VIS single-crystal spectroscopy. The IR spectra of the different samples commonly show a main intense OH stretching band located at 3563 cm^(-1), but other OH bands can sometimes be observed as well. Structural OH concentrations, calculated from the IR spectra, vary from about 0.006 to 0.240 wt% H_2O. The UV/VIS spectra indicate that there can be slight, but not fully understood, differences in the electronic state between synthetic and natural andradite crystals. The C_p behavior was determined by relaxation calorimetry between 2 and 300 K and by differential scanning calorimetry (DSC) methods between 150/300 and 700/950 K, employing the same andradite samples that were used for the other characterization measurements. The low-temperature C_p results show a magnetic phase transition with a Néel temperature of 11.3 ± 0.2 K, which could be slightly affected by the precise electronic state of Fe^(2+/3+) in the crystals. The published adiabatic calorimetry results on andradite do not provide a full and correct thermal description of this magnetic transition. The calorimetric Cp measurements give a best estimate for the standard third-law entropy at 298.15 K for andradite of S^o ≈ 324 ± 2 J/mol · K vs. the value of 316.4 ± 2.0 J/mol · K, as given in an early adiabatic investigation. Both natural and synthetic crystals give similar S o values within experimental uncertainty of about 1.0%, but one natural andradite, richer in OH, may have a very slightly higher value around S^o≈ 326 J/mol·K. Low-temperature DSC measurements made below 298 K agree excellently with those from relaxation calorimetry. The DSC measurements above 298 K show a similarity in C_p behavior among natural and synthetic andradites. A C_p polynomial for use above room temperature to approximately 1000 K was calculated from the data on synthetic andradite giving: C_p (J/mol·K) = 599.09 (±14) 2709.5 (±480)· T^(0.5) 1.3866 (±0.26)· 10^7 · T^2 + 1.6052 (±0.42) · 10^9 · T^3

Interpreting the Neutron's Electric Form Factor: Rest Frame Charge Distribution or Foldy Term?

The neutron's electric form factor contains vital information on nucleon structure, but its interpretation within many models has been obscured by relativistic effects. I demonstrate that, to leading order in the relativistic expansion of a constituent quark model, the Foldy term cancels exactly against a contribution to the Dirac form factor F_1 to leave intact the naive interpretation of G^n_E as arising from the neutron's rest frame charge distribution.Comment: 13 page