Are American Interlocking Directorates Associated with Brain Circulation and do They Translate into Higher Corporate Performance?

This study explores interlocking directorates, with specific focus on those connections when a director sits as an inside director for an American corporation and an outside director for firm located outside of North America. The goal of this study is to explore the spatial relationship between the personal histories of directors and the headquarter's location of the corporate boards on which they sit. First, it was found that a geographical relationship in the interlocking network of American companies exists. Second, it was determined that domestic personal histories played a significant role as 96.5 percent of directors attended a university in the United States and 93.4 percent directors were born there. When North American universities and North American births were deleted from the sample, a geographical pattern also emerges for Asian firms. Finally, the study found that the lone region that consistently displayed greater firm performance where a director's personal history and the interlocked company were the same as Asia.     

A moving group of young stars in Carina–Vela

Accurate two-colour photometry and proper motions of 7096 young X-ray stars in the ROSAT All-Sky Survey Bright Star Catalogue, version 1RXS, are extracted from the Tycho-2 Catalogue. The sample is dominated by red main-sequence and possibly pre-main-sequence stars. On a global proper motion convergence map, two features are very prominent: the nearby section of the Gould Belt and the Hyades convergent point. The appearance of the Gould Belt feature with its peak at ( l =2443, b =−126) is quite similar to that of Hipparcos OB stars. When only stars with proper motions drawing close to that point are selected, strong concentrations of stars in the direction of the Sco–Cen complex are found. Another concentration, not corresponding to any known OB association, is detected between the position of the Lower Centaurus Crux and Vela OB2 associations. It is a new young moving group located in Carina and Vela, and a near extension of the Sco–Cen complex. Contrary to the classical Gould Belt OB associations, the Carina–Vela moving group has a considerable geometric depth, the closest members being as near as 30 pc from the Sun. IC 2391, one of the youngest and closest open clusters on the sky, is a part of the Carina–Vela moving group. The Carina–Vela moving group does not link the Sco–Cen complex with the Vela OB associations, because the latter is much more distant than the outer limit of the sample. It is more likely that the young late-type population of the Scorpio–Centaurus–Carina moving group stretches towards the Sun and possibly beyond it.     

Molecular gas species in the lunar atmosphere

There is good evidence for the existence of very small amounts of methane, ammonia and carbon dioxide in the very tenuous lunar atmosphere which consists primarily of the rare gases helium, neon and argon. All of these gases, except⁴⁰Ar, originate from solar wind particles which impinge on the lunar surface and are imbedded in the surface material. Here they may form molecules before being released into the atmosphere, or may be released directly, as is the case for rare gases. Evidence for the existence of the molecular gas species is based on the pre-dawn enhancement of the mass peaks attributable to these compounds in the data from the Apollo 17 Lunar Mass Spectrometer. Methane is the most abundant molecular gas but its concentration is exceedingly low, 1 × 10³ mol cm^?3, slightly less than³⁶Ar, whereas the solar wind flux of carbon is approximately 2000 times that of³⁶Ar. Several reasons are advanced for the very low concentration of methane in the lunar atmosphere.     

Monazite–xenotime thermochronometry: methodology and an example from the Nepalese Himalaya

Monazite-xenotime thermochronometry involves the integration of petrographic, geochronological, and geochemical techniques to explore the thermal evolution of igneous and metamorphic rocks containing these accessory minerals. The method is illustrated in this paper by application to an orthogneiss sample from the Everest region of the Nepalese Himalaya that contains leucogranitic segregations produced by in-situ anatexis. Observations of phase relationships and the internal structure of accessory minerals made using both transmitted light and electron microscopy revealed the existence of multiple generations of monazite and xenotime and guided microsampling efforts to isolate grain fragments of Himalayan (Tertiary) and pre-Himalayan age. Nearly concordant U-Pb isotopic ratios for 13 single monazite and xenotime grains ranged in age from 28.37 to 17.598 Ma, making determination of the timing of anatexis difficult without additional information. Presuming that monazite and xenotime were in equilibrium over that entire interval, temperatures estimated from the yttrium contents of dated monazites range from 677-535 °C. Only the highest temperatures are consistent with experimental constraints on the conditions necessary to produce anatectic melts of appropriate composition, implying that the ~25.4-24.8 Ma dates for the grains with high apparent equilibration temperatures provide the best estimates for the age of anatexis. Two monazite crystals yielded ²⁰⁷Pb/²³⁵U dates that are statistically indistinguishable from the ²⁰⁷Pb/²³⁵U dates of coexisting xenotime crystals, permitting the application of both quantitative Y-partitioning and semi-quantitative Nd-partitioning thermometers as a cross-check for internal consistency. One of these sub-populations of accessory minerals, with a mean ²⁰⁷Pb/²³⁵U date of 22.364ǂ.097 Ma, provides inconsistent Y-partitioning (641ᆻ °C) and Nd-partitioning (515-560 °C) temperatures. We suspect the discrepancy may be caused by the high Th concentration (6.12 wt% ThO₂) in this subpopulation's monazite. The Y-partitioning thermometer was derived from experimental data for the (Ce, Y)PO₄ binary and may be inappropriate for application to high-Th monazites. For the other subpopulation (mean ²⁰⁷Pb/²³⁵U date=22.11ǂ.22 Ma), the Y- and Nd-partitioning temperatures are indistinguishable: 535ᇅ and 525-550 °C, respectively. This consistency strongly suggests that the sample experienced a temperature of ~535 °C at 22.11 Ma. This finding is tectonically important because temperatures at higher structural levels were much higher (by ~100 °C) at the same time, lending support to earlier suggestions of a major structural discontinuity within the upper part of the Himalayan metamorphic core at this longitude. An additional finding of uncertain importance is that inherited monazite and xenotime yielded U-Pb discordia with indistinguishable upper intercept ages (465.5NJ.7 and 470ᆟ Ma, respectively) and application of the Y-partitioning thermometer to the inherited monazites produced a restricted range of model temperatures averaging 470 °C. Whether or not these temperatures are geologically meaningful is unclear without independent corroboration of the assumption of equilibrium between the inherited monazites and xenotimes, but it appears that monazite-xenotime thermochronometry may be useful for "seeing through" high-grade metamorphism to extract temperature-time information about inherited mineral suites.     

Increasing Use of Human-Dominated Habitats as CO<Subscript>2</Subscript> Emissions Warm and Acidify Oceans

Urban and artificial structures are increasingly added to the world’s coasts during a time in which changing climate is forecast to drive shifts in naturally occurring habitats. We ask whether the role of artificial structures as marine habitats will increase in importance relative to their natural counterparts, particularly as natural habitats are negatively affected by ocean warming and acidification. To evaluate this model, we contrasted use of natural (kelp forest and turfing algae) and artificial habitat (plastic pier-piling) by a nest-building amphipod (Cymadusa pemptos) under current and future climate conditions of CO₂ and temperature. Under future conditions, amphipod populations in mesocosms increased, but this did not lead to greater proportional colonization of kelp and turf. Instead, colonization doubled in artificial habitats, and there was increasing production and occupation of nests on artificial habitats relative to natural habitats. In an age when human modification of natural substrata is increasingly cited as an agent of wildlife decline, understanding the future role of artificial habitats as replacement dwellings for natural habitats is critical. We pioneer an understanding of the future role of natural and artificial habitats, identifying the possibility that the role of urban structures as marine habitats may only increase.     

Chert provenance analysis at the Mack Canyon Site,Sherman County,Oregon: An evaluative study

Chert is the most frequent lithic raw material in the Columbia Plateau, but archaeologists have made few attempts to link chert artifacts to their quarries in this area. The Mack Canyon Site in north-central Oregon is near a chert source, providing an opportunity to compare provenance analysis techniques. Macroscopic and microscopic visual attributes and element concentrations were determined for 26 samples from six sources in the Columbia Plateau. Additional concentration data from two other sources were included for comparison. Four artifacts were selected from the Mack Canyon Site for comparison to the nearby outcrop. Although all of the artifacts were macroscopically indistinguishable from the local material, microscopic attributes and element concentrations indicate that only one of the artifacts came from the outcrop. Linking chert artifacts and quarries through statistical analysis of element concentrations holds promise for the Columbia Plateau. © 1996 John Wiley & Sons, Inc.     

Hunter‐gatherer response to late Holocene climatic variability in northern and central Australia

Sum probability analysis of 1275 radiometric ages from 608 archaeological sites across northern and central Australia demonstrates a changing archaeological signature that can be closely correlated with climate variability over the last 2 ka. Results reveal a marked increase in archaeological records across northern and central Australia over the last 2 ka, with notable declines in western and northern Australia between ca. AD 700 and 1000 and post‐AD 1500 – two periods broadly coeval with the Medieval Climatic Anomaly and the Little Ice Age as they have been documented in the Asia–Pacific region. Latitudinal and longitudinal analysis of the dataset suggests the increase in archaeological footprint was continent wide, while the declines were greatest from 9 to 20° S, 110 to 135° E and 143 to 150° E. The change in the archaeological data suggests that, combined with an increase in population over the late Holocene, a disruption or reorganisation of pre‐European resource systems occurred across Australia between ca. AD 700 and 1000 and post‐AD 1500. These archaeological responses can be broadly correlated with transitions of the El Niño–Southern Oscillation (ENSO) mean state on a multi‐decadal to centennial timescale. The latter involve a shift towards the La Niña‐like mean state with wetter conditions in the Australian region between AD 700 and 1150. A transition period in ENSO mean state occurred across Australia during AD 1150–1300, with persistent El Niño‐like and drier conditions to ca. AD 1500, and increasing ENSO variability post‐AD 1500 to the present. Copyright © 2010 John Wiley & Sons, Ltd.     

Accuracy of a pre-trained sentiment analysis (SA) classification model on tweets related to emergency response and early recovery assessment: the case of 2019 Albanian earthquake

Traditionally, earthquake impact assessments have been made via fieldwork by non-governmental organisations (NGO's) sponsored data collection; however, this approach is time-consuming, expensive and often limited. Recently, social media (SM) has become a valuable tool for quickly collecting large amounts of first-hand data after a disaster and shows great potential for decision-making. Nevertheless, extracting meaningful information from SM is an ongoing area of research. This paper tests the accuracy of the pre-trained sentiment analysis (SA) model developed by the no-code machine learning platform MonkeyLearn using the text data related to the emergency response and early recovery phase of the three major earthquakes that struck Albania on the 26th November 2019. These events caused 51 deaths, 3000 injuries and extensive damage. We obtained 695 tweets with the hashtags: #Albania #AlbanianEarthquake, and #albanianearthquake from the 26th November 2019 to the 3rd February 2020. We used these data to test the accuracy of the pre-trained SA classification model developed by MonkeyLearn to identify polarity in text data. This test explores the feasibility to automate the classification process to extract meaningful information from text data from SM in real-time in the future. We tested the no-code machine learning platform's performance using a confusion matrix. We obtained an overall accuracy (ACC) of 63% and a misclassification rate of 37%. We conclude that the ACC of the unsupervised classification is sufficient for a preliminary assessment, but further research is needed to determine if the accuracy is improved by customising the training model of the machine learning platform.

     

Mesospheric bore formation from large-scale gravity wave perturbations observed by collocated all-sky OH imager and sodium lidar

On 9 October 2007, long-horizontal-wavelength gravity waves were observed for the first time to steepen and form mesospheric bores at the altitude of ～87 km, by an all-sky OH imager located at Fort Collins (41°N, 105°W), Colorado. The collocated sodium lidar simultaneously observed the presence of a temperature inversion layer as the ducting region. One mesospheric bore uniquely later evolved into a large-amplitude soliton-like perturbation. When the gravity wave and the associated soliton-like perturbation passed through the lidar beams, the lidar detected strong vertical disturbance at 90 km, indicating convective instability. A large cold front system recorded several hours before in the troposphere was aligned to phase fronts of these large gravity waves. For all of the 7 mesospheric bores observed over a 5 year period, we found a similar alignment with a cold front 1000–1500 km away as the likely source of these large-scale gravity waves.