Origin of mesosiderites as a natural consequence of planet formation

The mineral composition of mesosiderites is described and a theory of the origin and evolution of these meteorites is presented. It is suggested that the asteroid parent body of the mesosiderites also formed in the inner solar system, perhaps just within the orbit of Mars. As a result of close planetary encounters, some bodies that formed near Earth or Venus were gravitationally perturbed into non-circular orbits; a few such bodies passed through the mesosiderite region at high relative velocities, colliding with and destroying a few of the native asteroids. Olivine-rich silicate mantles shattered into small pieces, but the stronger metal cores remained as large fragments. Much of the debris remained in circular orbits and accreted to the basaltic regoliths of intact native asteroids at low relative velocities. The large core fragments that collided with the crust greatly enriched restricted regions of the surface in metal. These localized regions were the mesosiderite progenitors; they accounted for only about 1% of the surface area of the parent bodies

A Durational Analysis of Inter-Syllabic and Intra-Syllabic /r/ Blends

No abstract provided by author

Increasing Low-income Residents’ Access to Fresh Produce through a Local Mobile Pantry

Seeds that Feed (STF) is a mobile food pantry located in Fayetteville, Arkansas. STF receives produce from local farmers to distribute to residents in low-income housing sites throughout Northwest Arkansas. According to Feeding America, food insecurity affected 14.3% Washington County, Arkansas’ population in 2016. The purpose of this study was to determine if STF’s model is an effective way to increase individuals’ access to fresh fruits and vegetables and increase their potential to meet the United States Department of Agriculture’s Food Patterns (USDA-FP) for to fruit and vegetable consumption. Twenty-three participants from three sites completed the study. A survey was used to collect basic demographics and dietary patterns. Record was taken of what foods each participant received on the survey day including plans for preparation and to whom it would be served. All anonymous responses were statistically analyzed using Excel. The results indicated that the likelihood to meet the USDA-FP for overall fruit and vegetable intake increased significantly after receiving approximately one cup of fruit and 1 ½ cups of vegetables from STF. A positive correlation was found between the number of times participants received produce from STF and participant’s total fruit intake and total intake of the “red/orange” and “other” vegetable subgroups. Therefore, STF’s model appears to be an effective method to increase access to fresh produce. Future research could utilize STF’s model to assess the potential for other supplemental nutrition programs to help low-income residents meet the USDA-FP and reduce food insecurity via mobile pantry

Parental Influence on Weight Biases in School-Age Children

Obesity rates have rapidly increased in America over the past few decades, and with this rise comes an increase in the negative psychosocial consequences experienced by victims of weight bias. Although a fair amount of research on weight bias (i.e., the negative attitudes or beliefs one holds toward overweight individuals) has been done in adults and adolescents, limited research has been done in young children. This study worked to fill gaps in the literature by investigating if children between the ages of five and nine would show weight biases, if the biases against individuals would vary by the ethnicity and gender of the target, and if children’s biases related to parents’ biases and health habits. To measure bias, children completed an explicit Anti-Fat Attitudes Questionnaire and a more implicit Figure Rating Scale examining biases toward individuals of varying gender and ethnicity. Parents also completed the Anti-Fat Attitudes Questionnaire and a health habits survey. Children displayed significant biases against overweight individuals, with more bias relating to the controllability of obesity. Children did not show different biases toward individuals of different genders and ethnicity, nor did their biases relate to parental views

The association of posttraumatic stress disorder and quality of life during the first year after acute coronary syndrome

Acute coronary syndrome [ACS, including unstable angina (UA) or myocardial infarction (MI)] events can be psychologically traumatic experiences for patients given their unpredictable, sudden onset and life-threatening nature [1]. Although posttraumatic stress disorder (PTSD) is commonly associated with index events of war or assault, PTSD is also associated with life-threatening illness and in particular ACS with approximately 12% of patients developing PTSD [1] and [2]. PTSD due to ACS has a multitude of consequences, including increased risk of ACS recurrence and mortality [3] and [4] in addition to PTSD itself being a debilitating psychiatric condition. Sufferers of PTSD are burdened by symptoms that include re-experiencing the traumatic event via intrusive thoughts, flashbacks, or nightmares; avoiding reminders of the index event; persistent negative alterations in cognition and mood; or physiologic hyperarousal. As such, ACS-induced PTSD is likely associated with substantial detriment in quality of life (QOL). However, few studies have measured this association, and no study has investigated it among a general ACS population or longitudinally. Rather, prior studies were composed of ACS patients only in intensive care units (ICUs) or among armed-services veterans [5], [6] and [7] or are notable for limitations such as cross-sectional designs [5] and [7]

Meteorites on Mars observed with the Mars Exploration Rovers

Reduced weathering rates due to the lack of liquid water and significantly greater typical surface ages should result in a higher density of meteorites on the surface of Mars compared to Earth. Several meteorites were identified among the rocks investigated during Opportunity’s traverse across the sandy Meridiani plains. Heat Shield Rock is a IAB iron meteorite and has been officially recognized as ‘‘Meridiani Planum.’’ Barberton is olivine-rich and contains metallic Fe in the form of kamacite, suggesting a meteoritic origin. It is chemically most consistent with a mesosiderite silicate clast. Santa Catarina is a brecciated rock with a chemical and mineralogical composition similar to Barberton. Barberton, Santa Catarina, and cobbles adjacent to Santa Catarina may be part of a strewn field. Spirit observed two probable iron meteorites from its Winter Haven location in the Columbia Hills in Gusev Crater. Chondrites have not been identified to date, which may be a result of their lower strengths and probability to survive impact at current atmospheric pressures. Impact craters directly associated with Heat Shield Rock, Barberton, or Santa Catarina have not been observed, but such craters could have been erased by eolian-driven erosion.Additional co-authors: DW Ming, RV Morris, PA de Souza Jr, SW Squyres, C Weitz, AS Yen, J Zipfel, T Economo

Assessing tidal marsh resilience to sea-level rise at broad geographic scales with multi-metric indices

Tidal marshes and the ecosystem services they provide may be at risk from sea-level rise (SLR). Tidal marsh resilience to SLR can vary due to differences in local rates of SLR, geomorphology, sediment availability and other factors. Understanding differences in resilience is critical to inform coastal management and policy, but comparing resilience across marshes is hindered by a lack of simple, effective analysis tools. Quantitative, multi-metric indices are widely employed to inform management of benthic aquatic ecosystems, but not coastal wetlands. Here, we develop and apply tidal marsh resilience to sea-level rise (MARS) indices incorporating ten metrics that contribute to overall marsh resilience to SLR. We applied MARS indices to tidal marshes at 16 National Estuarine Research Reserves across the conterminous U.S. This assessment revealed moderate resilience overall, although nearly all marshes had some indication of risk. Pacific marshes were generally more resilient to SLR than Atlantic ones, with the least resilient marshes found in southern New England. We provide a calculation tool to facilitate application of the MARS indices to additional marshes. MARS index scores can inform the choice of the most appropriate coastal management strategy for a marsh: moderate scores call for actions to enhance resilience while low scores suggest investment may be better directed to adaptation strategies such as creating opportunities for marsh migration rather than attempting to save existing marshes. The MARS indices thus provide a powerful new approach to evaluate tidal marsh resilience and to inform development of adaptation strategies in the face of SLR

Atomic response to strong laser pulses

We formulate a semiclassical model for the collective response of an atom to a strong laser pulse and use it to study the behavior of the valence shell of xenon. We find that, in a monochromatic wave, a fraction of the shell ionizes rapidly and the rest is driven coherently. The energy distributions of the emitted electrons show reasonable agreement with experimental distributions that are generated via single-particle ionization, indicating that the spectra are independent of the ionization dynamics. The remaining part of the shell is driven coherently and expands with time, thus exerting minimal effect on the core. We also analyze the effects of pulse shape, pulse duration, and the ponderomotive potential. In particular, we present results for femtosecond pulses

Molecular-dynamics simulations of atomic ionization by strong laser fields

We use molecular-dynamics simulations to study the competition between sequential and collective ionization in low-Z atoms by strong laser fields. The model shows sequential ionization at low fields, changing to collective ionization at large fields. The field strength at which this occurs is lower for higher frequencies. We also study the ionization as a function of pulse length and find that collective ionization is favored for shorter pulses

Search for Magnetic Monopoles Trapped in Matter

There have been many searches for magnetic monopoles in flight, but few for monopoles in matter. We have searched for magnetic monopoles in meteorites, schists, ferromanganese nodules, iron ores and other materials. The detector was a superconducting induction coil connected to a SQUID (Superconducting Quantum Interference Device) with a room temperature bore 15 cm in diameter. We tested a total of more than 331 kg of material including 112 kg of meteorites. We found no monopole and conclude the overall monopole/nucleon ratio in the samples is $<1.2 \times 10^{-29}$ with a 90\% confidence level.Comment: 6 pages, rev tex, no figure