Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Infant Ment Health J ; 39(3): 303-311, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29767412

RESUMO

Drawing on previous studies and the collective experience of conducting rigorous evaluations as part of the Tribal Maternal, Infant, and Early Childhood Home Visiting grants, we outline methodological considerations that will inform future research in tribal communities, particularly in the area of home visiting. The methodological issues we discuss are study design choices, measurement and data collection, and including community members in all aspects of the research.


Assuntos
Serviços de Saúde da Criança , Assistência à Saúde Culturalmente Competente/métodos , Serviços de Saúde do Indígena , Visita Domiciliar , Serviços de Saúde Materna , Projetos de Pesquisa , Adulto , Alaska , Pré-Escolar , Feminino , Humanos , Indígenas Norte-Americanos , Lactente , Recém-Nascido , Masculino , Avaliação das Necessidades , New Mexico , Gravidez , Washington , Adulto Jovem
2.
J Prim Prev ; 36(4): 275-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25921835

RESUMO

Growth in federal, state, and private funding is fueling the initiation of home visiting programs around the country. As communities expand home visiting programs, they need information to help them successfully start up new sites. This paper documents lessons learned about home visiting installation and initial implementation from the replication of the First Born(®) Program in six counties in New Mexico. Specifically, we examine how well sites met staffing, family referral and enrollment, program model fidelity, and financing goals in the first year of providing services. Data come from semi-structured interviews with program staff and document review. The findings are likely to be valuable to a wide spectrum of communities starting or expanding home visiting services, as well as to public and private funders of programs.


Assuntos
Visita Domiciliar , Cuidado do Lactente/normas , Serviços de Saúde Materno-Infantil/organização & administração , Pais/educação , Cuidado Pós-Natal/normas , Pré-Escolar , Implementação de Plano de Saúde/economia , Implementação de Plano de Saúde/métodos , Implementação de Plano de Saúde/organização & administração , Humanos , Lactente , Cuidado do Lactente/métodos , Recém-Nascido , Serviços de Saúde Materno-Infantil/economia , Serviços de Saúde Materno-Infantil/legislação & jurisprudência , Modelos Organizacionais , New Mexico , Patient Protection and Affordable Care Act , Cuidado Pós-Natal/métodos , Avaliação de Programas e Projetos de Saúde , Estados Unidos
3.
Nat Commun ; 14(1): 2254, 2023 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-37080977

RESUMO

Biominerals, such as nacreous bivalve shells, are important archives of environmental information. Most marine calcifiers form their shells from amorphous calcium carbonate, hypothesised to occur via particle attachment and stepwise crystallisation of metastable precursor phases. However, the mechanism of this transformation, including the incorporation of trace elements used for environmental reconstructions, are poorly constrained. Here, using shells of the Mediterranean mussel, we explore the formation of nacre from the meso- to the atomic scale. We use a combination of strontium pulse-chase labelling experiments in aquaculture and correlated micro- to sub-nanoscale analysis to show that nacre grows in a dynamic two-step process with extensional and space-filling growth components. Furthermore, we show that nacre crystallizes via localised dissolution and reprecipitation within nanogranules. Our findings elucidate how stepwise crystallization pathways affect trace element incorporation in natural biominerals, while preserving their intricate hierarchical ultrastructure.

4.
Phys Rev Lett ; 109(20): 202502, 2012 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-23215475

RESUMO

The interaction of an E/A=70-MeV (7)Be beam with a Be target was used to populate levels in (6)Be following neutron knockout reactions. The three-body decay of the ground and first excited states into the α+p+p exit channel were detected in the High Resolution Array. Precise three-body correlations extracted from the experimental data allowed us to obtain insight into the mechanism of the three-body democratic decay. The correlation data are in good agreement with a three-cluster-model calculation and thus validate this theoretical approach over a broad energy range.

5.
Phys Rev Lett ; 109(20): 202505, 2012 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-23215478

RESUMO

We report final-state-exclusive measurements of the light charged fragments in coincidence with (26)Ne residual nuclei following the direct two-proton removal from a neutron-rich (28)Mg secondary beam. A Dalitz-plot analysis and comparisons with simulations show that a majority of the triple-coincidence events with two protons display phase-space correlations consistent with the (two-body) kinematics of a spatially correlated pair-removal mechanism. The fraction of such correlated events, 56(12)%, is consistent with the fraction of the calculated cross section, 64%, arising from spin S=0 two-proton configurations in the entrance-channel (shell-model) (28)Mg ground state wave function. This result promises access to an additional and more specific probe of the spin and spatial correlations of valence nucleon pairs in exotic nuclei produced as fast secondary beams.

6.
Phys Rev Lett ; 104(11): 112701, 2010 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-20366470

RESUMO

Spectroscopic factors have been extracted for proton-rich 34Ar and neutron-rich 46Ar using the (p, d) neutron transfer reaction. The experimental results show little reduction of the ground state neutron spectroscopic factor of the proton-rich nucleus 34Ar compared to that of 46Ar. The results suggest that correlations, which generally reduce such spectroscopic factors, do not depend strongly on the neutron-proton asymmetry of the nucleus in this isotopic region as was reported in knockout reactions. The present results are consistent with results from systematic studies of transfer reactions but inconsistent with the trends observed in knockout reaction measurements.

7.
Rand Health Q ; 8(4)2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32582465

RESUMO

In 2015, First 5 LA contracted with the RAND Corporation to perform an implementation and outcomes evaluation of its Welcome Baby universal home visitation program. RAND designed and executed a mixed-methods implementation and outcomes evaluation program that examined program fidelity across 12 sites in Los Angeles County, each site's community referral and resource process, staff and participant experiences with the program, factors that may influence program attrition, short-term outcomes, and the relationship between program fidelity and outcomes. Data from multiple sources were used, including interviews with staff and focus groups with participants, quantitative data from staff and participant surveys, data collected by staff and entered into an administrative database, and document review. There was significant variation across the sites in meeting fidelity thresholds. Staff qualifications and training, reflective supervision, enrolling clients in the maternity ward, and service dosage elements were most challenging. Sites performed well in participant perceptions of their home visitor, supervisory requirements, and home visit content. Considerable variation in sites' community referral and resource process was also found. Welcome Baby participants achieved better outcomes compared to local and national benchmarks in more than half of the areas measured, including more positive parenting practices, higher levels of any breastfeeding, and safer sleep environments. Few clear patterns were evident in terms of relationships between meeting fidelity thresholds and outcomes. It is important to note challenges in evaluation, such as the lack of data to assess some of the fidelity and outcome domains.

8.
J Cosmet Sci ; 60(3): 337-45, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19586601

RESUMO

During hair coloring a number of disulfide bonds in cystine are oxidized (1) to create cysteic acid, forming binding sites for metal ions such as Ca(2+ )and Cu(2+ )from tap water (2). The increased uptake of these metals can have a detrimental impact on fiber properties-for example, reducing shine and causing a poor wet and dry feel (3). In addition, the increased uptake of copper can also contribute to further fiber damage during subsequent coloring due to its ability to take part in metal-induced radical chemistry (4). It is important to know where in the fibers these metals are located in order to either effectively remove these metals or control their chemistry. Nanoscale secondary ion mass spectrometry (NanoSIMS) has been used to locate the calcium and copper within hair that has been treated with a colorant and washed multiple times in tap water containing these ions. Untreated hair is used as a baseline standard material. Images with up to 50-nm spatial resolution of the preferential locations of calcium uptake were obtained, showing a high concentration of calcium in the cuticle region of colored hair, specifically in the sulfur-rich regions (A-layer and exocuticle).


Assuntos
Cálcio/farmacocinética , Cobre/farmacocinética , Tinturas para Cabelo , Cabelo/metabolismo , Humanos , Espectrometria de Massa de Íon Secundário
9.
Rand Health Q ; 7(4): 6, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30083418

RESUMO

The past two decades have been characterized by a growing body of research from diverse disciplines-child development, psychology, neuroscience, and economics, among others-demonstrating the importance of establishing a strong foundation in the early years of life. The research evidence has served to document the range of early childhood services that can successfully put children and families on the path toward lifelong health and well-being, especially those at greatest risk of poor outcomes. As early childhood interventions have proliferated, researchers have evaluated whether the programs improve children's outcomes and, when they do, whether the improved outcomes generate benefits that can outweigh the program costs. This study examines a set of evaluations that meet criteria for scientific rigor and synthesizes their results to better understand the outcomes, costs, and benefits of early childhood programs. The authors focus on evaluations of 115 early childhood programs serving children or parents of children from the prenatal period to age 5. Although preschool is perhaps the best-known early childhood intervention, the study also reviewed such programs as home visiting, parent education, government transfers providing cash and in-kind benefits, and those that use a combination of approaches. The findings demonstrate that most of the reviewed programs have favorable effects on at least one child outcome and those with an economic evaluation tend to show positive economic returns. With this expanded evidence base, policymakers can be highly confident that well-designed and -implemented early childhood programs can improve the lives of children and their families.

10.
Pediatrics ; 139(1)2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27980028

RESUMO

BACKGROUND AND OBJECTIVES: Evaluations of home visiting models have shown that they can reduce children's health care use in the first year of life. Models that exclusively use nurses as home visitors may cost more and be infeasible given nursing shortages in some locations. The goal of this study was to test whether a universal home visiting model employing a nurse-parent educator team as home visitors reduces health care use in the first year of life. METHODS: This study was a randomized controlled clinical trial of an intensive home visiting program delivered in homes of primary caregivers and their first-born children in Santa Fe, New Mexico. Intention-to-treat and contamination-adjusted intention-to-treat models were estimated, and 244 primary caregivers participated in the survey. RESULTS: In their first year of life, treatment group children were one-third less likely to visit the emergency department (control group mean, MC = 0.42, treatment group mean, MT = 0.28, P = .02) and were also 41% less likely to have visited a primary care provider ≥9 times (MC = 0.49, MT = 0.29, P < .001). We found no differences between the treatment and control groups for hospitalizations or injuries requiring medical attention. The universal program reduced infant health care use for high-risk and lower-risk families. CONCLUSIONS: Children in families randomly assigned to the program had less health care use in their first year, demonstrating that a universal prevention home visiting model delivered by a nurse-parent educator team can reduce infant health care use.


Assuntos
Serviços de Saúde da Criança/estatística & dados numéricos , Visita Domiciliar , Serviço Hospitalar de Emergência/estatística & dados numéricos , Estudos de Viabilidade , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Masculino , New Mexico , Enfermeiros de Saúde Comunitária , Pais/educação , Equipe de Assistência ao Paciente , Revisão da Utilização de Recursos de Saúde/estatística & dados numéricos
11.
Geobiology ; 15(2): 240-253, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27696636

RESUMO

Until now, descriptions of intracellular biomineralization of amorphous inclusions involving alkaline-earth metal (AEM) carbonates other than calcium have been confined exclusively to cyanobacteria (Couradeau et al., 2012). Here, we report the first evidence of the presence of intracellular amorphous granules of AEM carbonates (calcium, strontium, and barium) in unicellular eukaryotes. These inclusions, which we have named micropearls, show concentric and oscillatory zoning on a nanometric scale. They are widespread in certain eukaryote phytoplankters of Lake Geneva (Switzerland) and represent a previously unknown type of non-skeletal biomineralization, revealing an unexpected pathway in the geochemical cycle of AEMs. We have identified Tetraselmis cf. cordiformis (Chlorophyta, Prasinophyceae) as being responsible for the formation of one micropearl type containing strontium ([Ca,Sr]CO3 ), which we also found in a cultured strain of Tetraselmis cordiformis. A different flagellated eukaryotic cell forms barium-rich micropearls [(Ca,Ba)CO3 ]. The strontium and barium concentrations of both micropearl types are extremely high compared with the undersaturated water of Lake Geneva (the Ba/Ca ratio of the micropearls is up to 800,000 times higher than in the water). This can only be explained by a high biological pre-concentration of these elements. The particular characteristics of the micropearls, along with the presence of organic sulfur-containing compounds-associated with and surrounding the micropearls-strongly suggest the existence of a yet-unreported intracellular biomineralization pathway in eukaryotic micro-organisms.


Assuntos
Carbonatos/análise , Clorófitas/química , Clorófitas/metabolismo , Citoplasma/química , Lagos/microbiologia , Redes e Vias Metabólicas , Fitoplâncton/microbiologia , Suíça
12.
J Orthop Res ; 24(8): 1587-96, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16779825

RESUMO

Physical wear of orthopedic implants is inevitable. CoCr alloy samples, typically used in joint reconstruction, corrode rapidly after removal of the protective oxide layer. The behavior of CoCr pellets immersed in human serum, foetal bovine serum (FBS), synovial fluid, albumin in phosphate-buffered saline (PBS), EDTA in PBS, and water were studied using X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS). The difference in the corrosive nature of human serum, water, albumin in PBS and synovial fluid after 5 days of immersion was highlighted by the oxide layer, which was respectively 15, 3.5, 1.5, and 1.5 nm thick. The thickness of an additional calcium phosphate deposit from human serum and synovial fluid was 40 and 2 nm, respectively. Co and Cr ions migrated from the bulk metal surface and were trapped in this deposit by the phosphate anion. This may account for the composition of wear debris from CoCr orthopedic implants, which is known to consist predominantly of hydroxy-phosphate compounds. Known components of synovial fluid including proteoglycans, pyrophosphates, phospholipids, lubricin, and superficial zone protein (SZP), have been identified as possible causes for the lack of significant calcium phosphate deposition in this environment. Circulation of these compounds around the whole implant may inhibit calcium phosphate deposition.


Assuntos
Fosfatos de Cálcio/química , Ligas de Cromo/química , Sangue Fetal/química , Falha de Prótese , Líquido Sinovial/química , Albuminas/química , Animais , Soluções Tampão , Bovinos , Corrosão , Ácido Edético/química , Humanos , Técnicas In Vitro , Cloreto de Sódio , Espectrometria de Massa de Íon Secundário , Espectrometria por Raios X , Estresse Mecânico , Água/química
13.
Geobiology ; 14(5): 440-56, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27185586

RESUMO

Ambient inclusion trails (AITs) are tubular microstructures thought to form when a microscopic mineral crystal is propelled through a fine-grained rock matrix. Here, we report a new occurrence of AITs from a fossilized microbial mat within the 1878-Ma Gunflint Formation, at Current River, Ontario. The AITs are 1-15 µm in diameter, have pyrite as the propelled crystal, are infilled with chlorite and have been propelled through a microquartz (chert) or chlorite matrix. AITs most commonly originate at the boundary between pyrite- and chlorite-rich laminae and chert-filled fenestrae, with pyrite crystals propelled into the fenestrae. A subset of AITs originate within the fenestrae, rooted either within the chert or within patches of chlorite. Sulphur isotope data ((34) S/(32) S) obtained in situ from AIT pyrite have a δ(34) S of -8.5 to +8.0 ‰, indicating a maximum of ~30 ‰ fractionation from Palaeoproterozoic seawater sulphate (δ(34) S ≈ +20 ‰). Organic carbon is common both at the outer margins of the fenestrae and in patches of chlorite where most AITs originate, and can be found in smaller quantities further along some AITs towards the terminal pyrite grain. We infer that pyrite crystals now found within the AITs formed via the action of heterotrophic sulphate-reducing bacteria during early diagenesis within the microbial mat, as pore waters were becoming depleted in seawater sulphate. Gases derived from this process such as CO2 and H2 S were partially trapped within the microbial mat, helping produce birds-eye fenestrae, while rapid microquartz precipitation closed porosity. We propose that propulsion of the pyrite crystals to form AITs was driven by two complementary mechanisms during burial and low-grade metamorphism: firstly, thermal decomposition of residual organic material providing CO2 , and potentially CH4 , as propulsive gases, plus organic acids to locally dissolve the microquartz matrix; and secondly, reactions involving clay minerals that potentially led to enhanced quartz solubility, plus increases in fluid and/or gas pressure during chlorite formation, with chlorite then infilling the AITs. This latter mechanism is novel and represents a possible way to generate AITs in environments lacking organic material.


Assuntos
Bactérias/metabolismo , Fósseis , Sedimentos Geológicos/química , Elementos Químicos , Microscopia , Ontário , Rios , Espectrometria por Raios X
14.
Sci Rep ; 6: 20572, 2016 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-26853562

RESUMO

Coralline algae are a significant component of the benthic ecosystem. Their ability to withstand physical stresses in high energy environments relies on their skeletal structure which is composed of high Mg-calcite. High Mg-calcite is, however, the most soluble form of calcium carbonate and therefore potentially vulnerable to the change in carbonate chemistry resulting from the absorption of anthropogenic CO2 by the ocean. We examine the geochemistry of the cold water coralline alga Lithothamnion glaciale grown under predicted future (year 2050) high pCO2 (589 µatm) using Electron microprobe and NanoSIMS analysis. In the natural and control material, higher Mg calcite forms clear concentric bands around the algal cells. As expected, summer growth has a higher Mg content compared to the winter growth. In contrast, under elevated CO2 no banding of Mg is recognisable and overall Mg concentrations are lower. This reduction in Mg in the carbonate undermines the accuracy of the Mg/Ca ratio as proxy for past temperatures in time intervals with significantly different carbonate chemistry. Fundamentally, the loss of Mg in the calcite may reduce elasticity thereby changing the structural properties, which may affect the ability of L. glaciale to efficiently function as a habitat former in the future ocean.


Assuntos
Carbonato de Cálcio/química , Dióxido de Carbono/metabolismo , Rodófitas/metabolismo , Carbonato de Cálcio/metabolismo , Dióxido de Carbono/química , Ecossistema , Magnésio/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanotecnologia , Rodófitas/crescimento & desenvolvimento , Estações do Ano , Espectrometria de Massa de Íon Secundário , Temperatura , Difração de Raios X
15.
Biomaterials ; 74: 200-16, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26461115

RESUMO

Following neurotrauma, oxidative stress is spread via the astrocytic syncytium and is associated with increased aquaporin 4 (AQP4), inflammatory cell infiltration, loss of neurons and glia and functional deficits. Herein we evaluate multimodal polymeric nanoparticles functionalized with an antibody to an extracellular epitope of AQP4, for targeted delivery of an anti-oxidant as a therapeutic strategy following partial optic nerve transection. Using fluorescence microscopy, spectrophotometry, correlative nanoscale secondary ion mass spectrometry (NanoSIMS) and transmission electron microscopy, in vitro and in vivo, we demonstrate that functionalized nanoparticles are coated with serum proteins such as albumin and enter both macrophages and astrocytes when administered to the site of a partial optic nerve transection in rat. Antibody functionalized nanoparticles synthesized to deliver the antioxidant resveratrol are effective in reducing oxidative damage to DNA, AQP4 immunoreactivity and preserving visual function. Non-functionalized nanoparticles evade macrophages more effectively and are found more diffusely, including in astrocytes, however they do not preserve the optic nerve from oxidative damage or functional loss following injury. Our study highlights the need to comprehensively investigate nanoparticle location, interactions and effects, both in vitro and in vivo, in order to fully understand functional outcomes.


Assuntos
Doenças do Sistema Nervoso Central/tratamento farmacológico , Nanopartículas , Polímeros/uso terapêutico , Animais , Aquaporina 4/genética , Feminino , Polímeros/química , Ratos
16.
J Biomed Mater Res A ; 73(4): 456-67, 2005 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-15900610

RESUMO

The corrosion and dissolution of high- and low-carbon CoCrMo alloys, as used in orthopedic joint replacements, were studied by immersing samples in phosphate-buffered saline (PBS), water, and synovial fluid at 37 degrees C for up to 35 days. Bulk properties were analyzed with a fine ion beam microscope. Surface analyses by X-ray photoelectron spectroscopy and Auger electron spectroscopy showed surprisingly that synovial fluid produced a thin oxide/hydroxide layer. Release of ions into solution from the alloy also followed an unexpected pattern where synovial fluid, of all the samples, had the highest Cr concentration but the lowest Co concentration. The presence of carbide inclusions in the alloy did not affect the corrosion or the dissolution mechanisms, although the carbides were a significant feature on the metal surface. Only one mechanism was recognized as controlling the thickness of the oxide/hydroxide interface. The analysis of the dissolved metal showed two mechanisms at work: (1) a protein film caused ligand-induced dissolution, increasing the Cr concentration in synovial fluid, and was explained by the equilibrium constants; (2) corrosion at the interface increased the Co in PBS. The effect of prepassivating the samples (ASTM F-86-01) did not always have the desired effect of reducing dissolution. The release of Cr into PBS increased after prepassivation. The metal-synovial fluid interface did not contain calcium phosphate as a deposit, typically found where samples are exposed to calcium rich bodily fluids.


Assuntos
Ortopedia/métodos , Cloreto de Sódio/farmacologia , Líquido Sinovial/metabolismo , Vitálio/farmacologia , Água/farmacologia , Materiais Biocompatíveis , Soluções Tampão , Cálcio/química , Fosfatos de Cálcio/química , Carbono/química , Cromo/química , Temperatura Alta , Humanos , Hidróxidos/química , Íons , Teste de Materiais , Modelos Químicos , Fosfatos/farmacologia , Próteses e Implantes , Espectrometria por Raios X , Propriedades de Superfície , Temperatura , Termodinâmica , Fatores de Tempo
17.
Rand Health Q ; 4(3): 3, 2014 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-28560073

RESUMO

This article describes the evaluation of the New Mexico Home Visiting Competitive Development Grant, which sought to pilot test the use of implementation supports to improve the development and implementation of home visiting programs. Each community was to use Getting To Outcomes® (GTO) and ECHO® (Extension for Community Healthcare Outcomes) to support their work. The GTO framework promotes capacity for high-quality programming by specifying ten steps that practitioners should take and by providing support to complete those steps. ECHO involves specialists providing training and technical assistance via distance technology to community practitioners in rural areas to improve the quality of services. The grant was delayed, and the project's scope shifted significantly from the original plan. The evaluation documents significant challenges in meeting grant goals. A local team hired to facilitate GTO did not use it as designed, and no communities were trained in GTO. The coalitions that were developed operated with few resources or accountability, and made little progress on plans to enhance services. Only two of the four communities started home visiting after nearly a year and a half. ECHO was used with fidelity with those two programs. There was no change in the continuum of services to support children and families. Due to delays and lack of implementation of the proposed intervention, the evaluation was not able to assess the project's impact on child or family outcomes, nor did the project serve as a robust pilot test of the use of GTO and ECHO to improve home visiting implementation.

18.
Rand Health Q ; 2(1): 11, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-28083233

RESUMO

In Louisiana, the Community Foundation of Shreveport-Bossier pools funds from sources in Caddo and Bossier Parishes, manages the funds, and allocates the funding within the two-parish region. (The City of Shreveport is in Caddo Parish; the city of Bossier City is in Bossier Parish.) In 2008, the foundation selected education, health, and poverty as priority areas for its investments in children and families, and it asked the RAND Corporation to assist the community in identifying priority strategies within these three focus areas. RAND researchers developed a unique framework based on the intersection of needs, assets, and best practices. Applying this framework to the Shreveport-Bossier community, they identified health care providers, public school teachers, and Barksdale Air Force Base as strong assets that can help the community address three high-need areas: infant health, child maltreatment, and educational attainment. The "Needs-Assets-Best Practices" framework developed to assist the Shreveport-Bossier community can be applied in many other settings; this article can be viewed as a case study of the application of the framework.

19.
Geobiology ; 8(5): 403-16, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20597990

RESUMO

We here show that nano-scale mapping of elements commonly utilized in biological cycles provides a promising new additional line of evidence when evaluating the extent of the contribution of biology to microbialites. Our case study comes from Lake Clifton in Western Australia, a unique environment where living domical and conical microbialites occur in close proximity to ≤ 4000-year-old fossilized equivalents. The outer margins of a partially lithified, actively growing Lake Clifton microbialite are characterized by abundant filamentous cyanobacteria within a loosely cemented aragonite matrix. Nano-scale chemical maps have been successfully matched to specific morphological features such as trichomes, sheaths and putative extracellular polymeric substances (EPS). A suite of elements (C, O, Mg, N, Si, S) is concentrated within cyanobacterial sheaths, with carbon, magnesium, nitrogen and sulfur also enriched within trichomes and putative EPS. Calcium distribution highlights the sites of aragonite mineralization. In contrast, the fossilized Lake Clifton microbialite contains only rare, extensively degraded cyanobacterial filaments, the mean diameter of which is <50% of the living equivalents. Nevertheless, nano-scale chemical maps can again be matched with morphological features. Here, poorly preserved filamentous microfossils are highlighted by enrichments in nitrogen and sulfur. Magnesium is no longer concentrated within the filaments, instead it co-occurs with calcium and oxygen in the calcite cement. Extension of this study to a ~2720-million-year-old stromatolitic microbialite from the Tumbiana Formation of Western Australia shows that similar nano-scale signals, in particular nitrogen and sulfur enrichments, are characteristic of stromatolite laminations, even when morphological microfossils are absent. The close similarities of nano-scale elemental distributions in organic material from modern and ancient microbialites show that this technique provides a valuable addition to the morphological investigation of such structures, particularly in non-fossiliferous ancient examples.


Assuntos
Cianobactérias/ultraestrutura , Fósseis , Água Doce/microbiologia , Sedimentos Geológicos/microbiologia , Nanotecnologia/métodos , Espectrometria de Massa de Íon Secundário/métodos , Cianobactérias/química , Cianobactérias/crescimento & desenvolvimento , Água Doce/química , Sedimentos Geológicos/química , Nanoestruturas/análise , Nanoestruturas/ultraestrutura , Espectrometria de Massa de Íon Secundário/instrumentação , Austrália Ocidental
20.
Demography ; 47(1): 145-62, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20355688

RESUMO

This article tests whether parents reinforce or compensate for child endowments. We estimate how the difference in birth weight across siblings impacts specific parental investments: breast-feeding, well-baby visits, immunizations, and preschool attendance. Our results indicate that normal-birthweight children are 5%-11% more likely to receive early childhood parental investments than their low-birth-weight siblings. Moreover, the presence of additional low-birth-weight siblings in the household increases the likelihood of investments such as well-baby visits and immunizations for normal-birth-weight children. These results suggest that parental investments in early childhood tend to reinforce endowment differences.


Assuntos
Peso ao Nascer , Cuidado do Lactente , Poder Familiar , Alocação de Recursos , Adolescente , Adulto , Aleitamento Materno , Serviços de Saúde da Criança/estatística & dados numéricos , Pré-Escolar , Intervenção Educacional Precoce/estatística & dados numéricos , Feminino , Humanos , Imunização/estatística & dados numéricos , Lactente , Recém-Nascido de Baixo Peso , Recém-Nascido , Análise dos Mínimos Quadrados , Estudos Longitudinais , Modelos Econométricos , Mães , Estados Unidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA