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1.
J Child Adolesc Trauma ; 17(2): 373-381, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38938958

RESUMO

The purpose of this project is to assess, for practicing pediatric nurses in the U.S., what is the impact of the Stewards of Children Child Sexual Abuse (CSA) program on their attitudes about reporting suspected CSA. A sample size of 32 nurses completed an online 2-hour continuing education course by Stewards of Children, with a pre/post-test survey. A modified 14-item version of the Teachers Reporting Attitudes Scale for Child Sexual Abuse (TRAS-CSA) was used to measure the nurses' attitudes before and after educational training. The surveys were analyzed to assess changes in attitudes using two-tailed sign tests. Nurses' commitment to reporting CSA is high, even before training. Nurses' confidence in the system of reporting and in the response of authorities related to CSA increased after taking the Stewards of Children online course. While these results are limited in strength by low sample sizes and some null changes, they indicate that trainings like the Stewards of Children course can positively impact nurses' attitudes towards reporting CSA, particularly with regards to confidence in reporting, and therefore warrant further investigation into CSA training for nurses and its effects. Supplementary Information: The online version contains supplementary material available at 10.1007/s40653-023-00581-7.

2.
Sci Adv ; 9(28): eadh1003, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37450600

RESUMO

Preliminary analyses of asteroid Ryugu samples show kinship to aqueously altered CI (Ivuna-type) chondrites, suggesting similar origins. We report identification of C-rich, particularly primitive clasts in Ryugu samples that contain preserved presolar silicate grains and exceptional abundances of presolar SiC and isotopically anomalous organic matter. The high presolar silicate abundance (104 ppm) indicates that the clast escaped extensive alteration. The 5 to 10 times higher abundances of presolar SiC (~235 ppm), N-rich organic matter, organics with N isotopic anomalies (1.2%), and organics with C isotopic anomalies (0.2%) in the primitive clasts compared to bulk Ryugu suggest that the clasts formed in a unique part of the protoplanetary disk enriched in presolar materials. These clasts likely represent previously unsampled outer solar system material that accreted onto Ryugu after aqueous alteration ceased, consistent with Ryugu's rubble pile origin.


Assuntos
Carbono , Meteoroides , Carbono/análise , Sistema Solar , Silicatos
3.
Nat Commun ; 12(1): 436, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33469027

RESUMO

Many interpretations have been proposed to explain the presence of jarosite within Martian surficial sediments, including the possibility that it precipitated within paleo-ice deposits owing to englacial weathering of dust. However, until now a similar geochemical process was not observed on Earth nor in other planetary settings. We report a multi-analytical indication of jarosite formation within deep ice. Below 1000 m depth, jarosite crystals adhering on residual silica-rich particles have been identified in the Talos Dome ice core (East Antarctica) and interpreted as products of weathering involving aeolian dust and acidic atmospheric aerosols. The progressive increase of ice metamorphism and re-crystallization with depth, favours the relocation and concentration of dust and the formation of acidic brines in isolated environments, allowing chemical reactions and mineral neo-formation to occur. This is the first described englacial diagenetic mechanism occurring in deep Antarctic ice and supports the ice-weathering model for jarosite formation on Mars, highlighting the geologic importance of paleo ice-related processes on this planet. Additional implications concern the preservation of dust-related signals in deep ice cores with respect to paleoclimatic reconstructions and the englacial history of meteorites from Antarctic blue ice fields.

4.
Geochim Cosmochim Acta ; 269: 639-660, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32020947

RESUMO

We carried out a coordinated mineralogical and isotopic study of a Wark-Lovering (WL) rim on a Ca,Al-rich inclusion (CAI) from the reduced CV3 chondrite Vigarano. The outermost edge of the CAI mantle is mineralogically and texturally distinct compared to the underlying mantle that is composed of coarse, zoned melilite (Åk~10-60) grains. The mantle edge contains fine-grained gehlenite with hibonite and rare grossite that likely formed by rapid crystallization from a melt enriched in Ca and Al. These gehlenite and hibonite layers are surrounded by successive layers of spinel, zoned melilite (Åk~0-10), zoned diopside that grades outwards from Al,Ti-rich to Al,Ti-poor, and forsteritic olivine intergrown with diopside. These layered textures are indicative of sequential condensation of spinel, melilite, diopside, and forsterite onto hibonite. Anorthite occurs as a discontinuous layer that corrodes adjacent melilite and Al-diopside, and appears to have replaced them, probably even later than the forsterite layer formation. Based on these observations, we conclude that the WL rim formation was initiated by flash melting and extensive evaporation of the original inclusion edge, followed by subsequent gas-solid reactions under highly dynamic conditions. All the WL rim minerals are 16O-rich (Δ17O = ~-23‰), indicating their formation in an 16O-rich nebular reservoir. Our Al-Mg measurements of hibonite, spinel, and diopside from the WL rim, as well as spinel and Al,Ti-diopside in the core, define a single, well-correlated isochron with an inferred initial 26Al/27Al ratio of (4.94 ± 0.12) × 10-5. This indicates that the WL rim formed shortly after the host CAI. In contrast, the lack of 26Mg excesses in the WL rim anorthite suggest its later formation or later isotopic disturbance in the solar nebula, after 26Al had decayed.

5.
Chem Erde ; 79(4)2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32020946

RESUMO

A coordinated mineralogical and oxygen isotopic study of four fine-grained calcium-, aluminum-rich inclusions (CAIs) from the ALHA77307 CO3.0 carbonaceous chondrite was conducted. Three of the inclusions studied, 05, 1-65, and 2-119, all have nodular structures that represent three major groups, melilite-rich, spinel-rich, and hibonite-rich, based on their primary core mineral assemblages. A condensation origin was inferred for these CAIs. However, the difference in their primary core mineralogy reflects unique nebular environments in which multiple gas-solid reactions occurred under disequilibrium conditions to form hibonite, spinel, and melilite with minor perovskite and Al,Ti-rich diopside. A common occurrence of a diopside rim on the CAIs records a widespread event that marks the end of their condensation as a result of isolation from a nebular gas. An exception is a rare inclusion 2-112 that contains euhedral spinel crystals embedded in melilite, suggesting this CAI had been re-melted. All of the fine-grained CAIs analyzed in ALHA77307 are uniformly 16O-rich with an average Δ17O value of ~-22 ± 5‰ (2σ), indicating no apparent correlation between their textures and oxygen isotopic compositions. We therefore conclude that a prevalent 16O-rich gas reservoir existed in a region of the solar nebula where CO3 fine-grained CAIs formed, initially by condensation and then later, some of them were reprocessed by melting event(s).

6.
Science ; 314(5806): 1720-4, 2006 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-17170291

RESUMO

Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution in abundance and composition. Some organics are similar, but not identical, to those in interplanetary dust particles and carbonaceous meteorites. A class of aromatic-poor organic material is also present. The organics are rich in oxygen and nitrogen compared with meteoritic organics. Aromatic compounds are present, but the samples tend to be relatively poorer in aromatics than are meteorites and interplanetary dust particles. The presence of deuterium and nitrogen-15 excesses suggest that some organics have an interstellar/protostellar heritage. Although the variable extent of modification of these materials by impact capture is not yet fully constrained, a diverse suite of organic compounds is present and identifiable within the returned samples.


Assuntos
Meteoroides , Compostos Orgânicos/análise , Carbono/análise , Poeira Cósmica/análise , Deutério/análise , Nitrogênio/análise , Isótopos de Nitrogênio/análise , Oxigênio/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Astronave
7.
Science ; 314(5806): 1728-31, 2006 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-17170293

RESUMO

Infrared spectra of material captured from comet 81P/Wild 2 by the Stardust spacecraft reveal indigenous aliphatic hydrocarbons similar to those in interplanetary dust particles thought to be derived from comets, but with longer chain lengths than those observed in the diffuse interstellar medium. Similarly, the Stardust samples contain abundant amorphous silicates in addition to crystalline silicates such as olivine and pyroxene. The presence of crystalline silicates in Wild 2 is consistent with mixing of solar system and interstellar matter. No hydrous silicates or carbonate minerals were detected, which suggests a lack of aqueous processing of Wild 2 dust.


Assuntos
Hidrocarbonetos/análise , Meteoroides , Silicatos/análise , Poeira Cósmica/análise , Astronave , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Science ; 314(5806): 1735-9, 2006 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-17170295

RESUMO

The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk.

9.
Science ; 314(5804): 1439-42, 2006 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-17138898

RESUMO

Coordinated transmission electron microscopy and isotopic measurements of organic globules in the Tagish Lake meteorite shows that they have elevated ratios of nitrogen-15 to nitrogen-14 (1.2 to 2 times terrestrial) and of deuterium to hydrogen (2.5 to 9 times terrestrial). These isotopic anomalies are indicative of mass fractionation during chemical reactions at extremely low temperatures (10 to 20 kelvin), characteristic of cold molecular clouds and the outer protosolar disk. The globules probably originated as organic ice coatings on preexisting grains that were photochemically processed into refractory organic matter. The globules resemble cometary carbon, hydrogen, oxygen, and nitrogen (CHON) particles, suggesting that such grains were important constituents of the solar system starting materials.


Assuntos
Carbono/análise , Hidrogênio/análise , Meteoroides , Nitrogênio/análise , Isótopos de Carbono/análise , Deutério/análise , Gelo , Isótopos de Nitrogênio/análise , Oxigênio/análise , Temperatura , Raios Ultravioleta
10.
Science ; 309(5735): 737-41, 2005 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-15994379

RESUMO

An interplanetary dust particle contains a submicrometer crystalline silicate aggregate of probable supernova origin. The grain has a pronounced enrichment in 18O/16O (13 times the solar value) and depletions in 17O/16O (one-third solar) and 29Si/28Si (<0.8 times solar), indicative of formation from a type II supernova. The aggregate contains olivine (forsterite 83) grains <100 nanometers in size, with microstructures that are consistent with minimal thermal alteration. This unusually iron-rich olivine grain could have formed by equilibrium condensation from cooling supernova ejecta if several different nucleosynthetic zones mixed in the proper proportions. The supernova grain is also partially encased in nitrogen-15-rich organic matter that likely formed in a presolar cold molecular cloud.


Assuntos
Poeira Cósmica/análise , Compostos de Ferro/análise , Compostos de Magnésio/análise , Meteoroides , Silicatos/análise , Cristalização , Isótopos/análise , Nitrogênio/análise , Isótopos de Nitrogênio/análise , Isótopos de Oxigênio/análise , Silício/análise , Temperatura
11.
Science ; 300(5616): 105-8, 2003 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-12610229

RESUMO

We have identified six circumstellar silicate grains within interplanetary dust particles (IDPs). Their extrasolar origins are demonstrated by their extremely anomalous oxygen isotopic compositions. Three 17O-rich grains appear to originate from red giant or asymptotic giant branch stars. One 16O-rich grain may be from a metal-poor star. Two 16O-poor grains have unknown stellar sources. One of the grains is forsterite, and two are amorphous silicate "GEMS" (glass with embedded metal and sulfides), which is consistent with astronomical identifications of crystalline and amorphous silicates in the outflows of evolved stars. These observations suggest cometary origins of these IDPs and underscore the perplexing absence of silicates among circumstellar dust grains from meteorites.


Assuntos
Astronomia , Poeira Cósmica , Isótopos de Oxigênio , Silicatos , Fenômenos Astronômicos , Carbono , Meteoroides , Sistema Solar , Temperatura
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