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1.
Curr Biol ; 33(17): 3702-3710.e5, 2023 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-37607548

RESUMO

In intimate ecological interactions, the interdependency of species may result in correlated demographic histories. For species of conservation concern, understanding the long-term dynamics of such interactions may shed light on the drivers of population decline. Here, we address the demographic history of the monarch butterfly, Danaus plexippus, and its dominant host plant, the common milkweed Asclepias syriaca (A. syriaca), using broad-scale sampling and genomic inference. Because genetic resources for milkweed have lagged behind those for monarchs, we first release a chromosome-level genome assembly and annotation for common milkweed. Next, we show that despite its enormous geographic range across eastern North America, A. syriaca is best characterized as a single, roughly panmictic population. Using approximate Bayesian computation with random forests (ABC-RF), a machine learning method for reconstructing demographic histories, we show that both monarchs and milkweed experienced population expansion during the most recent recession of North American glaciers 10,000-20,000 years ago. Our data also identify concurrent population expansions in both species during the large-scale clearing of eastern forests (∼200 years ago). Finally, we find no evidence that either species experienced a reduction in effective population size over the past 75 years. Thus, the well-documented decline of monarch abundance over the past 40 years is not visible in our genomic dataset, reflecting a possible mismatch of the overwintering census population to effective population size in this species.


Assuntos
Asclepias , Borboletas , Animais , Asclepias/genética , Borboletas/genética , Teorema de Bayes , Densidade Demográfica , Genômica
2.
Nat Commun ; 14(1): 4389, 2023 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-37474517

RESUMO

Recently nitrogen-hydrogen compounds have successfully been applied as co-catalysts for mild conditions ammonia synthesis. Ca2NH was shown to act as a H2 sink during reaction, with H atoms from its lattice being incorporated into the NH3(g) product. Thus the ionic transport and diffusion properties of the N-H co-catalyst are fundamentally important to understanding and developing such syntheses. Here we show hydride ion conduction in these materials. Two distinct calcium nitride-hydride Ca2NH phases, prepared via different synthetic paths are found to show dramatically different properties. One phase (ß) shows fast hydride ionic conduction properties (0.08 S/cm at 600 °C), on a par with the best binary ionic hydrides and 10 times higher than CaH2, whilst the other (α) is 100 times less conductive. An in situ combined analysis techniques reveals that the effective ß-phase conducts ions via a vacancy-mediated phenomenon in which the charge carrier concentration is dependent on the ion concentration in the secondary site and by extension the vacancy concentration in the main site.

3.
Nat Commun ; 14(1): 2917, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37217479

RESUMO

Topochemistry enables step-by-step conversions of solid-state materials often leading to metastable structures that retain initial structural motifs. Recent advances in this field revealed many examples where relatively bulky anionic constituents were actively involved in redox reactions during (de)intercalation processes. Such reactions are often accompanied by anion-anion bond formation, which heralds possibilities to design novel structure types disparate from known precursors, in a controlled manner. Here we present the multistep conversion of layered oxychalcogenides Sr2MnO2Cu1.5Ch2 (Ch = S, Se) into Cu-deintercalated phases where antifluorite type [Cu1.5Ch2]2.5- slabs collapsed into two-dimensional arrays of chalcogen dimers. The collapse of the chalcogenide layers on deintercalation led to various stacking types of Sr2MnO2Ch2 slabs, which formed polychalcogenide structures unattainable by conventional high-temperature syntheses. Anion-redox topochemistry is demonstrated to be of interest not only for electrochemical applications but also as a means to design complex layered architectures.

4.
J Mater Chem A Mater ; 11(9): 4559-4571, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36866387

RESUMO

Chloride-based solid electrolytes are considered interesting candidates for catholytes in all-solid-state batteries due to their high electrochemical stability, which allows the use of high-voltage cathodes without protective coatings. Aliovalent Zr(iv) substitution is a widely applicable strategy to increase the ionic conductivity of Li3M(iii)Cl6 solid electrolytes. In this study, we investigate how Zr(iv) substitution affects the structure and ion conduction in Li3-x In1-x Zr x Cl6 (0 ≤ x ≤ 0.5). Rietveld refinement using both X-ray and neutron diffraction is used to make a structural model based on two sets of scattering contrasts. AC-impedance measurements and solid-state NMR relaxometry measurements at multiple Larmor frequencies are used to study the Li-ion dynamics. In this manner the diffusion mechanism and its correlation with the structure are explored and compared to previous studies, advancing the understanding of these complex and difficult to characterize materials. It is found that the diffusion in Li3InCl6 is most likely anisotropic considering the crystal structure and two distinct jump processes found by solid-state NMR. Zr-substitution improves ionic conductivity by tuning the charge carrier concentration, accompanied by small changes in the crystal structure which affect ion transport on short timescales, likely reducing the anisotropy.

5.
Inorg Chem ; 62(4): 1628-1635, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36650095

RESUMO

Significant oxide ion conductivity has previously been reported for the Ba3M'M″O8.5 family (M' = Nb5+, V5+; M″ = Mo6+, W6+) of cation-deficient hexagonal perovskite derivatives. These systems exhibit considerable structural disorder and competitive occupation of two distinct oxygen positions (O3 site and O2 site), enabling two-dimensional (2D) ionic conductivity within the ab plane of the structure; higher occupation of the tetrahedral O3 site vs the octahedral O2 site is known to be a major factor that promotes oxide ion conductivity. Previous chemical doping studies have shown that substitution of small amounts of the M' or M″ ions can result in significant changes to both the structure and ionic conductivity. Here, we report on the electrical and structural properties of the Ba3Nb1-xTaxMoO8.5 series (x = 0.00, 0.025, 0.050, 0.100). AC impedance measurements show that substitution of Nb5+ with Ta5+ leads to a significant increase in low-temperature (<500 °C) conductivity for x = 0.1. Analysis of neutron and X-ray diffraction (XRD) data confirms that there is a decrease in the M1O4/M1O6 ratio upon increasing x from 0 to 0.1 in Ba3Nb1-xTaxMoO8.5, which would usually coincide with a lowering in the conductivity. However, neutron diffraction results show that Ta doping causes an increase in the oxide ion conductivity as a result of longer M1-O3 bonds and increased polyhedral distortion.

6.
ACS Phys Chem Au ; 3(1): 74-83, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36718264

RESUMO

This work investigates the acid sites in a commercial ZSM-5 zeolite catalyst by a combination of spectroscopic and physical methods. The Brønsted acid sites in such catalysts are associated with the aluminum substituted into the zeolite lattice, which may not be identical to the total aluminum content of the zeolite. Inelastic neutron scattering spectroscopy (INS) directly quantifies the concentrations of Brønsted acid protons, silanol groups, and hydroxyl groups associated with extra-framework aluminum species. The INS measurements show that ∼50% of the total aluminum content of this particular zeolite is extra framework, a conclusion supported by solid-state NMR and ammonia temperature-programmed desorption (TPD) measurements. Evidence for the presence of extra-framework aluminum oxide species is also seen in neutron powder diffraction data from proton- and deuterium-exchanged samples. The differences between results from the different analytical methods are discussed, and the novelty of direct proton counting by INS in this typical commercial catalyst is emphasized.

7.
PLoS One ; 17(7): e0270839, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35834543

RESUMO

In an empirical analysis of transposable element (TE) abundance within natural populations of Mimulus guttatus and Drosophila melanogaster, we found a surprisingly high variance of TE count (e.g., variance-to-mean ratio on the order of 10 to 300). To obtain insight regarding the evolutionary genetic mechanisms that underlie the overdispersed population distributions of TE abundance, we developed a mathematical model of TE population genetics that includes the dynamics of element proliferation and purifying selection on TE load. The modeling approach begins with a master equation for a birth-death process and extends the predictions of the classical theory of TE dynamics in several ways. In particular, moment-based analyses of population distributions of TE load reveal that overdispersion is likely to arise via copy-and-paste proliferation dynamics, especially when the elementary processes of proliferation and excision are approximately balanced. Parameter studies and analytic work confirm this result and further suggest that overdispersed population distributions of TE abundance are probably not a consequence of purifying selection on total element load.


Assuntos
Elementos de DNA Transponíveis , Drosophila melanogaster , Animais , Elementos de DNA Transponíveis/genética , Drosophila melanogaster/genética , Evolução Molecular , Genética Populacional , Seleção Genética
8.
J Soc Work End Life Palliat Care ; 18(2): 160-176, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35317703

RESUMO

The purpose of this study was to investigate responses to death at multiple levels within the assisted living (AL) system and to characterize the psychosocial impact of death on surviving residents. This study used secondary thematic analysis of multiple data sources collected as part of a larger quantitative-focused study with 21 ALs. Data sources included: (a) community documents, e.g., newsletters; (b) descriptive and reflective observational field notes; and (c) memos and key statements from interviews with residents (n = 18). Three themes emerged from the data: administrative memorialization practices, resident perceptions of staff communication related to death, and resident psychosocial responses to death. Surviving residents reported using both adaptive and avoidant strategies to cope with psychological responses to death; noting that grief responses extended to the loss of the deceased resident's family, friends, and pets. Residents also perceived staff-resident communication and community memorialization practices as incongruent with a "family-like" social climate. Findings highlight the potential utility of a multi-level approach to improving psychosocial aspects of end-of-life care and grief management by targeting AL administration, workforce, and individuals. Social workers are well-positioned to lead these types of psychosocial interventions but must contend with staffing barriers limiting clinical roles in AL.


Assuntos
Luto , Assistência Terminal , Comunicação , Amigos , Pesar , Humanos , Assistentes Sociais
9.
Insects ; 13(1)2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-35055931

RESUMO

Tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), is an economically damaging pest in cotton production systems across the southern United States. We systematically scouted 120 commercial cotton fields across five southeastern states during susceptible growth stages in 2019 and 2020 to investigate sampling optimization and the effect of interface crop and landscape composition on L. lineolaris abundance. Variance component analysis determined field and within-field spatial scales, compared with agricultural district and state, accounted for more variation in L. lineolaris density using sweep net and drop cloth sampling. This result highlights the importance of field-level scouting efforts. Using within-field samples, a fixed-precision sampling plan determined 8 and 23 sampling units were needed to determine L. lineolaris population estimates with 0.25 precision for sweep net (100 sweeps per unit) and drop cloth (1.5 row-m per unit) sampling, respectively. A spatial Bayesian hierarchical model was developed to determine local landscape (<0.5 km from field edges) effects on L. lineolaris in cotton. The proportion of agricultural area and double-crop wheat and soybeans were positively associated with L. lineolaris density, and fields with more contiguous cotton areas negatively predicted L. lineolaris populations. These results will improve L. lineolaris monitoring programs and treatment management decisions in southeastern USA cotton.

10.
J Interpers Violence ; 37(23-24): NP21672-NP21698, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-34978934

RESUMO

Sexual assault of men by women has received increasing attention in recent years, as has research on rape myths about male victims. This study is a cross-generational replication of a 1984 study of college students' judgments about male and female victims in a scenario involving a sexual assault carried out by male or female assailants. The 1984 data (n = 172) were compared with those of a 2019 cohort (n = 372) in a 2 (participant gender) x 2 (assailant gender) x 2 (victim gender) x 2 (cohort) factorial design to assess potential generational changes in perceptions of victims. Judgments by male participants of male victims of assaults carried out by women changed notably over time. The 2019 male cohort was less likely to judge that the victim initiated or encouraged the incident (40% in 1984 compared with 15% in 2019) and derived pleasure from it (47.4% in 1984 compared with 5.8% in 2019). In contrast, the 2019 female cohort was more likely to attribute victim encouragement (26.9% compared with 4.3% in 1984) and pleasure to the male victim (25% in 2019 compared with 5% in 1984). A similar gender pattern occurred in judgments of how stressful the event was for the male victim. Analysis of the 2019 data revealed that overall, despite scientific and cultural shifts that have occurred over the past three decades, participants continued to judge the male victim of assault by a female to have been more encouraging and to have experienced more pleasure and less stress than in any other assailant/victim gender combination. Results are discussed in relation to gendered stereotypical beliefs and male rape myths, as well as possible sensitization to power differentials inspired by the #MeToo movement. We emphasize the need for greater awareness and empirical attention to abuse that runs counter to preconceived notions about sexual victimization.


Assuntos
Vítimas de Crime , Estupro , Delitos Sexuais , Feminino , Humanos , Masculino , Julgamento , Identidade de Gênero
12.
J Aging Environ ; 35(3): 319-337, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34485981

RESUMO

This study classified assisted living (AL) residents by expectations for future physical, cognitive, and socioemotional health in later life. The authors analyzed cross-sectional data from 202 AL residents. Study participants completed the 12-item expectations regarding aging survey. A K-means cluster analysis identified three subgroups: "lower expectations" (n = 55), "higher expectations" (n = 70), and "expecting adaptiveness" (n = 77). Subgroups varied by select demographic, health, and relocation-related factors. Results suggest that, despite similarities in physical and cognitive functioning, AL residents reported different expectations for health. Socioemotional functioning may help explain observed discrepancies between current health and future health-related expectations.

13.
ACS Mater Lett ; 3(5): 652-657, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-34476400

RESUMO

State-of-the-art oxides and sulfides with high Li-ion conductivity and good electrochemical stability are among the most promising candidates for solid-state electrolytes in secondary batteries. Yet emerging halides offer promising alternatives because of their intrinsic low Li+ migration energy barriers, high electrochemical oxidative stability, and beneficial mechanical properties. Mechanochemical synthesis has enabled the characterization of LiAlX4 compounds to be extended and the iodide, LiAlI4, to be synthesized for the first time (monoclinic P21/c, Z = 4; a = 8.0846(1) Å; b = 7.4369(1) Å; c = 14.8890(2) Å; ß = 93.0457(8)°). Of the tetrahaloaluminates, LiAlBr4 exhibited the highest ionic conductivity at room temperature (0.033 mS cm-1), while LiAlCl4 showed a conductivity of 0.17 mS cm-1 at 333 K, coupled with the highest thermal and oxidative stability. Modeling of the diffusion pathways suggests that the Li-ion transport mechanism in each tetrahaloaluminate is closely related and mediated by both halide polarizability and concerted complex anion motions.

14.
Inorg Chem ; 60(17): 13550-13556, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34405996

RESUMO

The hexagonal perovskite derivatives Ba3NbMoO8.5, Ba3NbWO8.5, and Ba3VWO8.5 have recently been reported to exhibit significant oxide ion conductivity. Here, we report the synthesis and crystal structure of the hexagonal perovskite derivative Ba3-xVMoO8.5-x. Rietveld refinement from neutron and X-ray diffraction data show that the cation vacancies are ordered on the M2 site, leading to a structure consisting of palmierite-like layers of M1Ox polyhedra separated by vacant octahedral layers. In contrast to other members of the Ba3M'M″O8.5 family, Ba3-xVMoO8.5-x is not stoichiometric and both barium and oxygen vacancies are present. Although synthesized in air at elevated temperatures, Ba3-xVMoO8.5-x is unstable at lower temperatures, as illustrated by the formation of BaCO3 and BaMoO4 by heat treatment in air at 400 °C. This precludes measurement of the electrical properties. However, bond-valence site energy (BVSE) calculations strongly suggest that oxide ion conductivity is present in Ba3-xVMoO8.5-x.

15.
Chem Commun (Camb) ; 57(57): 7027-7030, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-34165482

RESUMO

Magnetic interactions within Mn-(µ-O)2-Mn pairs are crucial to the function of some essential enzymes and catalysts, but their nature is unclear. Neutron diffraction reveals that similar units in BiMnPO5 show ferromagnetic coupling which has been rationalized by density functional theory modelling and calculations of magnetic exchange energies. The results are important to many solid state and biological systems.


Assuntos
Bismuto/química , Magnetismo , Manganês/química , Catálise , Teoria da Densidade Funcional , Enzimas/química , Enzimas/metabolismo , Conformação Molecular , Difração de Nêutrons , Oxigênio/química
16.
Plant Cell ; 33(7): 2235-2257, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-33895820

RESUMO

Endosperm is an angiosperm innovation central to their reproduction whose development, and thus seed viability, is controlled by genomic imprinting, where expression from certain genes is parent-specific. Unsuccessful imprinting has been linked to failed inter-specific and inter-ploidy hybridization. Despite their importance in plant speciation, the underlying mechanisms behind these endosperm-based barriers remain poorly understood. Here, we describe one such barrier between diploid Mimulus guttatus and tetraploid Mimulus luteus. The two parents differ in endosperm DNA methylation, expression dynamics, and imprinted genes. Hybrid seeds suffer from underdeveloped endosperm, reducing viability, or arrested endosperm and seed abortion when M. guttatus or M. luteus is seed parent, respectively, and transgressive methylation and expression patterns emerge. The two inherited M. luteus subgenomes, genetically distinct but epigenetically similar, are expressionally dominant over the M. guttatus genome in hybrid embryos and especially their endosperm, where paternal imprints are perturbed. In aborted seeds, de novo methylation is inhibited, potentially owing to incompatible paternal instructions of imbalanced dosage from M. guttatus imprints. We suggest that diverged epigenetic/regulatory landscapes between parental genomes induce epigenetic repatterning and global shifts in expression, which, in endosperm, may uniquely facilitate incompatible interactions between divergent imprinting schemes, potentially driving rapid barriers.


Assuntos
Mimulus/metabolismo , Genoma de Planta/genética , Impressão Genômica/genética , Impressão Genômica/fisiologia , Hibridização Genética , Mimulus/genética , Sementes/genética , Sementes/metabolismo
17.
Nat Commun ; 12(1): 2272, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33859176

RESUMO

Spin-ices are frustrated magnets that support a particularly rich variety of emergent physics. Typically, it is the interplay of magnetic dipole interactions, spin anisotropy, and geometric frustration on the pyrochlore lattice that drives spin-ice formation. The relevant physics occurs at temperatures commensurate with the magnetic interaction strength, which for most systems is 1-5 K. Here, we show that non-magnetic cadmium cyanide, Cd(CN)2, exhibits analogous behaviour to magnetic spin-ices, but does so on a temperature scale that is nearly two orders of magnitude greater. The electric dipole moments of cyanide ions in Cd(CN)2 assume the role of magnetic pseudospins, with the difference in energy scale reflecting the increased strength of electric vs magnetic dipolar interactions. As a result, spin-ice physics influences the structural behaviour of Cd(CN)2 even at room temperature.

18.
Vet Anim Sci ; 11: 100167, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33553802

RESUMO

COVID-19 led to sudden changes in human activities, mainly due to restrictive measures required to supress the virus. We assess the preliminary evidence for impacts on animal health and welfare in Scottish aquaculture, a key economic activity in remoter areas of the country. We summarise the industry structure, explore pathways of vulnerability to aquatic animal disease within a One Health framework that may be accentuated by impacts of COVID-19, and use basic routine data collection on the key welfare indicators of salmon mortality and parasitic sea lice counts. The indicators were published on schedule and provide no evidence of gross impact on health and welfare, at least for salmon, during the period of intensive lockdown restrictions in Scotland. Longer term effects cannot be ruled out and we do not assess impacts on the economic or social aspects of aquaculture production.

19.
Home Healthc Now ; 39(1): 13-19, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33417357

RESUMO

The U.S. Department of Veterans Affairs Home-Based Primary Care program (HBPC) serves Veterans with multiple comorbid physical and psychological conditions that can increase suicide risk. HBPC teams are uniquely able to implement suicide risk assessment and prevention practices, and the team's mental health provider often trains other team members. An online suicide prevention toolkit was developed for HBPC mental health providers and their teams as part of a quality improvement project. Toolkit development was guided by a needs assessment consisting of first focus group and then data from surveys of HBPC program directors (n = 53) and HBPC mental health providers (n = 56). Needs identified by both groups included training specific to the HBPC patient population and more resources if mental health needs could not be fully managed by the HBPC team. HBPC mental health providers within integrated care teams play a key role in clinical intervention, policy development, and interprofessional team education on suicide prevention. HBPC teams have specific learning and support needs around suicide prevention that can be addressed with a feasible, easily accessible clinical and training resource.


Assuntos
Serviços de Assistência Domiciliar , Prevenção do Suicídio , Veteranos , Humanos , Atenção Primária à Saúde , Estados Unidos , United States Department of Veterans Affairs
20.
World Neurosurg ; 151: 258-276, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33385605

RESUMO

The incorporation of perspective into art and science revolutionized the study of the brain. Beginning in about 1504, Leonardo da Vinci began to model the ventricles of the brain in three dimensions. A few years later, Andreus Vesalius illustrated radically novel brain dissections. Thomas Willis' work, Cerebri Anatome (1664), illustrated by Christopher Wren, remarkably showed the brain undersurface. Later, in the early 1800s, Charles Bell's accurate images of neural structures changed surgery. In the 1960s, Albert L. Rhoton Jr. (1932-2016) began to earn his place among the preeminent neuroanatomists by focusing his lens on microanatomy to harness a knowledge of microneurosurgery, master microneurologic anatomy, and use it to improve the care of his patients. Although his biography and works are well known, no analysis has been conducted to identify the progression, impact, and trends in the totality of his publications, and no study has assessed his work in a historical context compared with the contributions of other celebrated anatomists. We analyzed 414 of 508 works authored by Rhoton; these studies were analyzed according to subjects discussed, including anatomic region, surgical approaches, subjects covered, anatomic methods used, forms of multimedia, and subspecialty. Rhoton taught detailed neuroanatomy from a surgical perspective using meticulous techniques that evolved as the technical demands of neurosurgery advanced, inspiring students and contemporaries. His work aligns him with renowned figures in neuroanatomy, arguably establishing him historically as the most influential anatomist of the neurosurgical era.


Assuntos
Encéfalo/cirurgia , Neuroanatomia , Neurocirurgia/educação , Procedimentos Neurocirúrgicos/educação , Ventrículos Cerebrais/cirurgia , Humanos , Conhecimento
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