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1.
Chaos ; 34(4)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38587537

RESUMO

We explore the nonlinear interactions of an optomechanical microresonator driven by two external optical signals. Optical whispering-gallery waves are coupled to acoustic surface waves of a fused silica medium in the equatorial plane of a generic microresonator. The system exhibits coexisting attractors whose behaviors include limit cycles, steady states, tori, quasi-chaos, and fully developed chaos with ghost orbits of a known attractor. Bifurcation diagrams demonstrate the existence of self-similarity, periodic windows, and coexisting attractors and show high-density lines within chaos that suggests a potential ghost orbit. In addition, the Lyapunov spectral components as a function of control parameter illuminate the dynamic nature of attractors and periodic windows with symmetric and asymmetric formations, their domains of existence, their bifurcations, and other nonlinear effects. We show that the power-shift method can access accurately and efficiently attractors in the optomechanical system as it does in other nonlinear systems. To test whether the ghost orbit is the link between two attractors interrupted by chaos, we examine the elements of the bifurcation diagrams as a function of control parameter. We also use detuning as a second control parameter to avoid the chaotic region and clarify that the two attractors are one.

2.
Chaos ; 31(1): 013120, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33754793

RESUMO

Coexisting attractors are studied in a single-mode coherent model of a laser with an injected signal. We report that every attractor has a unique Lyapunov exponent (LE) pattern that is choreographed by the subtle variations in the attractor's dynamics and circumscribed by a common Lyapunov spectral pattern that begins and ends with two-zero LEs. Lyapunov spectra form symmetric-like and asymmetric bubbles; the former foreshadows an attractor's proximity to the cusp of an eminent change in dynamics and the latter indicates the presence of a bifurcation. We show that the peak values of the asymmetric bubbles are always associated with two-zero LEs; in fact, they are allied inseparably in forecasting period-doubling episodes. The two-zero LEs' predictor of torus dynamics is refined to include the convergence of three LEs to a triplet of zeros as a precursor to the two-zero spectra. We report that the long-standing two-zero LEs' signature is a necessary but not sufficient condition for predicting attractors and their dynamic conditions. The evolution of the attractor volume as a function of the injected signal is compared to the spectral formation of the attractor; we report slope changes and points of inflections in the volume trajectory where spectral changes indicate dynamic changes. Attractor viability is tested preliminarily by including random low-level noise in the frequency of the injected signal.

3.
Nature ; 576(7786): 232-236, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31802002

RESUMO

Remote observations of the solar photospheric light scattered by electrons (the K-corona) and dust (the F-corona or zodiacal light) have been made from the ground during eclipses1 and from space at distances as small as 0.3 astronomical units2-5 to the Sun. Previous observations6-8 of dust scattering have not confirmed the existence of the theoretically predicted dust-free zone near the Sun9-11. The transient nature of the corona has been well characterized for large events, but questions still remain (for example, about the initiation of the corona12 and the production of solar energetic particles13) and for small events even its structure is uncertain14. Here we report imaging of the solar corona15 during the first two perihelion passes (0.16-0.25 astronomical units) of the Parker Solar Probe spacecraft13, each lasting ten days. The view from these distances is qualitatively similar to the historical views from ground and space, but there are some notable differences. At short elongations, we observe a decrease in the intensity of the F-coronal intensity, which is suggestive of the long-sought dust free zone9-11. We also resolve the fine-scale plasma structure of very small eruptions, which are frequently ejected from the Sun. These take two forms: the frequently observed magnetic flux ropes12,16 and the predicted, but not yet observed, magnetic islands17,18 arising from the tearing-mode instability in the current sheet. Our observations of the coronal streamer evolution confirm the large-scale topology of the solar corona, but also reveal that, as recently predicted19, streamers are composed of yet smaller substreamers channelling continual density fluctuations at all visible scales.

4.
J Nutr Health Aging ; 20(8): 841-844, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27709233

RESUMO

OBJECTIVE: Apolipoprotein E4 (APOE4) genotype has been implicated as a moderating factor in cognitive function studies. Although prior studies have suggested that vitamin C is associated with better cognitive function in elders, link between the two has been mixed. Limited data exist as to whether the APOE4 genotype influences these associations. Therefore, this study sought to determine whether the association between vitamin C and cognition in a rural community dwelling cohort differs by the APOE4 genotype. DESIGN AND PARTICIPANTS: Data were analyzed on 582 participants (n=183 men; n=399 women) from a rural community-based cohort. Cognition was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status and The Executive Interview. APOE genotyping was ascertained by standard methods. The relation between vitamin C supplementation and cognition were analyzed first with ANOVA and then ANCOVA with age, gender, education as covariates. Analyses were initially run in the full sample and then split by APOE4 presence (yes/no). RESULTS: Overall, Vitamin C supplementation was associated with significantly better immediate memory (p=0.04), visuospatial skills (p=0.002), language (p=0.01), and global cognitive functioning (p=0.006). Among APOE4 non-carriers, vitamin C supplementation was positively associated with immediate memory (F[1,392] =6.7, p=0.01), visuospatial skills (F[1,391]=10.6, p=0.001), language (F[1,392]=13.0, p<0.001), attention (F[1,386]=7.9, p=0.005, and global cognition (F[1,382]=11.0, p=0.001. However, there was no significant link between vitamin C supplementation and cognition among APOE4 carriers. CONCLUSION: Vitamin C supplementation was found to be positively associated with cognition among this rural-dwelling community-based sample; however, the associations appeared to differ by APOE4 status. These data may suggest that targeted genotype-specific cognitive enhancement studies are needed to clarify the potential benefits of vitamin C supplementation.


Assuntos
Apolipoproteína E4/uso terapêutico , Ácido Ascórbico/uso terapêutico , Idoso , Apolipoproteína E4/genética , Ácido Ascórbico/administração & dosagem , Cognição , Feminino , Genótipo , Humanos , Masculino , População Rural
5.
Cell Death Dis ; 6: e1700, 2015 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-25789975

RESUMO

LincRNA-p21 is a long noncoding RNA and a transcriptional target of p53 and HIF-1α. LincRNA-p21 regulates gene expression in cis and trans, mRNA translation, protein stability, the Warburg effect, and p53-dependent apoptosis and cell cycle arrest in doxorubicin-treated mouse embryo fibroblasts. p53 plays a key role in the response of skin keratinocytes to UVB-induced DNA damage by inducing cell cycle arrest and apoptosis. In skin cancer development, UVB-induced mutation of p53 allows keratinocytes upon successive UVB exposures to evade apoptosis and cell cycle arrest. We hypothesized that lincRNA-p21 has a key functional role in UVB-induced apoptosis and/or cell cycle arrest in keratinocytes and loss of lincRNA-p21 function results in the evasion of apoptosis and/or cell cycle arrest. We observed that lincRNA-p21 transcripts are highly inducible by UVB in mouse and human keratinocytes in culture and in mouse skin in vivo. LincRNA-p21 is regulated at the transcriptional level in response to UVB, and the UVB induction of lincRNA-p21 in keratinocytes and in vivo in mouse epidermis is primarily through a p53-dependent pathway. Knockdown of lincRNA-p21 blocked UVB-induced apoptosis in mouse and human keratinocytes, and lincRNA-p21 was responsible for the majority of UVB-induced and p53-mediated apoptosis in keratinocytes. Knockdown of lincRNA-p21 had no effect on cell proliferation in untreated or UVB-treated keratinocytes. An early event in skin cancer is the mutation of a single p53 allele. We observed that a mutant p53(+/R172H) allele expressed in mouse epidermis (K5Cre(+/tg);LSLp53(+/R172H)) showed a significant dominant-negative inhibitory effect on UVB-induced lincRNA-p21 transcription and apoptosis in epidermis. We conclude lincRNA-p21 is highly inducible by UVB and has a key role in triggering UVB-induced apoptotic death. We propose that the mutation of a single p53 allele provides a pro-oncogenic function early in skin cancer development through a dominant inhibitory effect on UVB-induced lincRNA-p21 expression and the subsequent evasion of UVB-induced apoptosis.


Assuntos
Apoptose/genética , RNA Longo não Codificante/biossíntese , Neoplasias Cutâneas/genética , Proteína Supressora de Tumor p53/genética , Animais , Apoptose/efeitos da radiação , Pontos de Checagem do Ciclo Celular/genética , Pontos de Checagem do Ciclo Celular/efeitos da radiação , Linhagem Celular , Proliferação de Células/genética , Proliferação de Células/efeitos da radiação , Dano ao DNA/genética , Dano ao DNA/efeitos da radiação , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Queratinócitos/metabolismo , Queratinócitos/patologia , Queratinócitos/efeitos da radiação , Camundongos , RNA Longo não Codificante/genética , Pele/metabolismo , Pele/patologia , Pele/efeitos da radiação , Neoplasias Cutâneas/patologia , Raios Ultravioleta
6.
Psychol Med ; 44(5): 1005-13, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23834781

RESUMO

BACKGROUND: The triarchic model of psychopathy characterizes the disorder in terms of three distinguishable phenotypic facets: disinhibition, meanness and boldness. The present study sought to (1) inform current debates regarding the role of boldness in the definition of psychopathy and (2) clarify boundaries between psychopathy and antisocial personality disorder (ASPD). METHOD: This study evaluated the degree to which facets of the triarchic model are represented in the most widely used clinical inventory for psychopathy, the Psychopathy Checklist - Revised (PCL-R), in comparison with ASPD as defined by DSM-IV criteria. Adult male offenders from two distinct correctional settings (n = 157 and 169) were investigated to ensure replicability of findings across samples exhibiting high base rates of psychopathy and antisocial behavior. RESULTS: We found evidence for convergent and discriminant validity of the three triarchic facets in predicting symptomatic components of psychopathy as assessed by the PCL-R. Additionally, and crucially vis-à-vis current debates in the field, we found that boldness contributed incrementally (over and above disinhibition and meanness) to prediction of PCL-R psychopathy, in particular its interpersonal style component, but not ASPD. CONCLUSIONS: The three distinct facets of the triarchic model of psychopathy are represented clearly and distinctly in the PCL-R, with boldness through its interpersonal facet, but not in DSM-defined ASPD. Our findings suggest that boldness is central to diagnostic conceptions of psychopathy and distinguishes psychopathy from the more prevalent diagnosis of ASPD.


Assuntos
Transtorno da Personalidade Antissocial/classificação , Criminosos/psicologia , Modelos Psicológicos , Adolescente , Adulto , Transtorno da Personalidade Antissocial/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
7.
Environ Pollut ; 159(12): 3474-83, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21889245

RESUMO

A model assuming first-order losses by evasion and leaching was used to evaluate Hg dynamics in UK soils since 1850. Temporal deposition patterns of Hg were constructed from literature information. Inverse modelling indicated that 30% of 898 rural sites receive Hg only from the global circulation, while in 51% of cases local deposition exceeds global. Average estimated deposition is 16 µg Hg m(-2) a(-1) to rural soils, 19 µg Hg m(-2) a(-1) to rural and non-rural soils combined. UK soils currently hold 2490 tonnes of reactive Hg, of which 2140 tonnes are due to anthropogenic deposition, mostly local in origin. Topsoil currently releases 5.1 tonnes of Hg(0) per annum to the atmosphere, about 50% more than the anthropogenic flux. Sorptive retention of Hg in the lower soil exerts a strong control on surface water Hg concentrations. Following decreases in inputs, soil Hg concentrations are predicted to decline over hundreds of years.


Assuntos
Poluição Ambiental/história , Mercúrio/análise , Poluentes do Solo/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental/história , História do Século XIX , História do Século XX , História do Século XXI , Reino Unido
8.
Environ Pollut ; 159(12): 3721-9, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21839559

RESUMO

The median total mercury concentration in 898 UK rural topsoils, sampled between 1998 and 2008, was 0.095 µg g(-1). Approximate adjustment for unreactive metal produced an estimate of 0.052 µg g(-1) for reactive Hg. The highest concentrations were in the north and west, where organic-rich soils with low bulk densities dominate, but the spatial pattern was quite different if soil Hg pools (mg m(-2)) were considered, the highest values being near to the industrial north of England and London. Possible toxic effects of Hg were best evaluated by comparison with soil Critical Limits expressed as ratios of Hg to soil organic matter, or soil solution Hg(2+) concentrations, estimated by chemical speciation modelling. Only a few percent of the rural UK soils showed exceedance, and this also applied to rural soils from the whole of Europe. UK urban and industrial soils had higher Hg concentrations and more cases of exceedance.


Assuntos
Monitoramento Ambiental , Mercúrio/análise , Poluentes do Solo/análise , Europa (Continente) , Reino Unido
9.
Clin Oncol (R Coll Radiol) ; 21(8): 591-7, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19589665

RESUMO

AIMS: HIV infection is associated with an increased incidence of glioblastoma multiforme (GBM). Here we report four new cases of HIV-associated GBM, discuss these in the context of previously reported cases, and consider aspects of current glioma management in HIV-positive patients. METHODS AND RESULTS: Twenty-one cases of GBM in HIV-positive patients, including four treated recently at our own institution, are discussed. The median age at presentation of the whole series was 38 years (range 19-60 years). The median CD4 count at GBM presentation was 400 cells/mm(3) (range 80-610 cells/mm(3)). Patients had been HIV positive for a median of 3 years (range 0-11 years) before tumour presentation. Treatment and survival were analysed in 16 of the 21 patients (five published cases were excluded: three due to lack of further information and two spinal cord tumours). Treatment included surgical debulking, radical radiotherapy and chemotherapy, all of which were well tolerated. The median survival was 8 months for the 16 patients with assessable data. CONCLUSIONS: GBM occurs at an increased frequency and younger age in the HIV population than in the general population. HIV itself is not found in glioma specimens, but the effect of HIV infection on reduced immune surveillance is thought to promote the development of these tumours. The approach to management of HIV-positive patients with GBM should be the same as the general population, using surgery, radiotherapy and chemotherapy. Vincristine should be used with caution due to potential interactions with highly active antiretroviral therapy, causing an increased rate of autonomic neuropathy. Continuous low-dose temozolomide treatment should also be used cautiously because of potential additive lymphopenia. Survival of glioma patients with HIV is dictated by their tumour, not their HIV status.


Assuntos
Glioblastoma/terapia , Infecções por HIV/complicações , Adulto , Antineoplásicos Alquilantes/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Dacarbazina/análogos & derivados , Dacarbazina/uso terapêutico , Feminino , Glioblastoma/etiologia , Glioblastoma/cirurgia , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Temozolomida , Adulto Jovem
10.
Physiol Biochem Zool ; 82(5): 483-94, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19572807

RESUMO

Hemoglobin (Hb) polymorphism in cod is associated with temperature-related differences in biogeographical distribution, and several authors have suggested that functional characteristics of the various hemoglobin isoforms (HbIs) directly influence phenotypic traits such as growth rate. However, no study has directly examined whether Hb genotype translates into physiological differences at the whole animal level. Thus, we generated a family of juvenile Atlantic cod consisting of all three main Hb genotypes (HbI-1/1, HbI-2/2, and HbI-1/2) by crossing a single pair of heterozygous parents, and we compared their metabolic and cortisol responses to an acute thermal challenge (10 degrees C to their critical thermal maximum [CTM] or 22 degrees C, respectively) and tolerance of graded hypoxia. There were no differences in routine metabolism (at 10 degrees C), maximum metabolic rate, metabolic scope, CTM (overall mean 22.9 degrees +/- 0.2 degrees), or resting and poststress plasma cortisol levels among Hb genotypes. Further, although the HbI-1/1 fish grew more (by 15%-30% during the first 9 mo) when reared at 10 degrees +/- 1 degrees C and had a slightly enhanced hypoxia tolerance at 10 degrees C (e.g., the critical O(2) levels for HbI-1/1, HbI-2/2, and HbI-1/2 cod were 35.56% +/- 1.24% , 40.56% +/- 1.99%, and 40.20% +/- 1.19% air saturation, respectively), these results are contradictory to expectations based on HbI functional properties. Thus, our findings (1) do not support previous assumptions that growth rate differences among cod Hb genotypes result from a more efficient use of the oxygen supply-that is, reduced standard metabolic rates and/or increased metabolic capacity-and (2) suggest that in juvenile cod, there is no selective advantage to having a particular Hb genotype with regards to the capacity to withstand ecologically relevant environmental challenges.


Assuntos
Gadus morhua/genética , Gadus morhua/fisiologia , Hemoglobinas/genética , Aclimatação , Animais , Ecossistema , Meio Ambiente , Feminino , Doenças dos Peixes/genética , Doenças dos Peixes/fisiopatologia , Gadus morhua/sangue , Gadus morhua/crescimento & desenvolvimento , Genótipo , Heterozigoto , Hibridização Genética , Hidrocortisona/sangue , Hipóxia/genética , Hipóxia/fisiopatologia , Hipóxia/veterinária , Masculino , Estresse Fisiológico
11.
Artigo em Inglês | MEDLINE | ID: mdl-20403769

RESUMO

Expression level of genes associated with oxygen [cytochrome oxidase 1 (COX1) and myoglobin (Mb)] and glucose utilization [glucose transporters (GLUTs) and hexokinases (HKs)] along with metabolic indices were determined in Atlantic cod (Gadus morhua) subjected to an hypoxic challenge of <45% oxygen saturation for 24 days. There were two closely related HKs considered to be homologues of mammalian HKIs. HKIa and HKIb share 86% sequence identity and are both ubiquitously expressed. Mb was also expressed in many tissues with highest levels occurring in heart. Over the first 15 days of hypoxia there were transient increases in plasma lactate in hypoxic relative to normoxic fish associated with a significant decrease in liver glycogen. Over days 1-6, there were in ten of eleven cases, increased average (with a number of conditions being statistically significant) expression levels of GLUTs (1, 2, 4) and HKs (1a and b) in gill, heart, liver, and white muscle in hypoxic relative to normoxic fish. There were significant increases in COX1 and Mb expression levels in gill by day 24 but no changes in these aerobic indicators in heart or liver. Overall the data suggest a transient increase in genes associated with glucose utilization during the early part of the hypoxic challenge followed by alterations in gene expression in gill.


Assuntos
Proteínas de Peixes/genética , Gadus morhua/genética , Gadus morhua/metabolismo , Expressão Gênica , Glucose/metabolismo , Oxigênio/metabolismo , Sequência de Aminoácidos , Animais , Clonagem Molecular , DNA Complementar/genética , Proteínas de Peixes/química , Proteínas de Peixes/metabolismo , Dados de Sequência Molecular , Especificidade de Órgãos , Fosforilação , Filogenia , Alinhamento de Sequência
12.
Fish Shellfish Immunol ; 24(5): 600-9, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18343685

RESUMO

Sea-caged cod are limited in their movements in the water column, and thus can be exposed to large seasonal ( approximately 0-20 degrees C) temperature fluctuations. To investigate the physiological response of Atlantic cod to summer-like increases in temperature, we exposed 10 degrees C acclimated juvenile cod to a graded thermal challenge (1 degrees C increase every 5 days) and measured: (1) plasma cortisol and glucose levels; (2) the respiratory burst activity of blood leukocytes; and (3) the expression of specific immune-related genes [MHC Class I, Interleukin-1beta (IL-1beta), beta2-microglobulin (beta2-M), Immunoglobulin M (IgM)-light (L) and -heavy (H) chains] in the blood using quantitative reverse transcription-polymerase chain reaction (QRT-PCR). The experiment was stopped at 19.1 degrees C, with 26.7% of the fish surviving to this point. Plasma glucose levels increased slightly at 16 and 18 degrees C (by 1.39- and 1.74-fold, respectively), in contrast, cortisol levels were elevated significantly (by 2.9-fold) at 16 degrees C but returned to control levels thereafter. The effect of increasing temperature on the expression of immune related genes in blood cells (leukocytes) was variable and depended on the gene of interest. The expression of IgM-H remained stable for the duration of the experiment. In contrast, IL-1beta expression was increased significantly (by approximately 25-fold) at 19 degrees C as compared to time-matched control fish, and changes in the expression of beta2-M, MHC Class I and IgM-L followed a pattern similar to that seen for cortisol: increasing at 16 degrees C (by 4.2-, 5.3- and 17-fold, respectively), but returning to pre-stress levels by 19 degrees C. Interestingly, increasing temperatures had no effect on respiratory burst activity. This study is the first to examine the effects of a chronic regimen of increasing temperature on the stress physiology and immunology of a marine teleost, and suggests that immune function is influenced by complex interactions between thermal effects and temperature-induced stress (elevated circulating cortisol levels).


Assuntos
Gadus morhua/imunologia , Gadus morhua/fisiologia , Temperatura Alta , Água do Mar , Estresse Fisiológico/veterinária , Animais , Glicemia/análise , Gadus morhua/genética , Regulação da Expressão Gênica , Genes MHC Classe I/genética , Hidrocortisona/sangue , Interleucina-1beta/genética , Fator 1 de Elongação de Peptídeos/genética , Explosão Respiratória/imunologia , Soroglobulinas/genética , Estresse Fisiológico/genética , Estresse Fisiológico/imunologia , Estresse Fisiológico/fisiopatologia , Tempo
13.
Environ Pollut ; 152(1): 41-9, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17630059

RESUMO

During the last 50 years nitrate concentrations in Buttermere and Wastwater (Cumbria, UK) have risen significantly, by 70 and 100%, respectively. By estimating contemporary nitrate fluxes in the lakes' catchments and in sub-catchments and comparing them with the fractional areas of different soil types, it is deduced that the surface water nitrate is derived almost entirely from organic-rich ranker soils that have a limited ability to retain atmospherically-deposited nitrogen. Little or no nitrate leaches from the other major soil type, a brown podzol, despite it having a lower C:N ratio (12.0 g g(-1)) than the ranker (17.0 g g(-1)), nor is there much contribution from the small areas of improved (chemically fertilised) grassland within the catchments. Although some nitrate leaching is occurring, total N losses are appreciably smaller than atmospheric inputs, so the catchment soils are currently accumulating between 3 and 4 g N m(-2) a(-1).


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Nitratos/análise , Poluentes Químicos da Água/análise , Adsorção , Carbono/análise , Inglaterra , Fertilizantes , Água Doce , Concentração de Íons de Hidrogênio , Nitrogênio/análise , Solo/análise , Tempo , Movimentos da Água
14.
Sci Total Environ ; 382(2-3): 199-213, 2007 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-17555799

RESUMO

Critical loads are the basis for policies controlling emissions of acidic substances in Europe and elsewhere. They are assessed by several elaborate and ingenious models, each of which requires many parameters, and have to be applied on a spatially-distributed basis. Often the values of the input parameters are poorly known, calling into question the validity of the calculated critical loads. This paper attempts to quantify the uncertainty in the critical loads due to this "parameter uncertainty", using examples from the UK. Models used for calculating critical loads for deposition of acidity and nitrogen in forest and heathland ecosystems were tested at four contrasting sites. Uncertainty was assessed by Monte Carlo methods. Each input parameter or variable was assigned a value, range and distribution in an objective a fashion as possible. Each model was run 5000 times at each site using parameters sampled from these input distributions. Output distributions of various critical load parameters were calculated. The results were surprising. Confidence limits of the calculated critical loads were typically considerably narrower than those of most of the input parameters. This may be due to a "compensation of errors" mechanism. The range of possible critical load values at a given site is however rather wide, and the tails of the distributions are typically long. The deposition reductions required for a high level of confidence that the critical load is not exceeded are thus likely to be large. The implication for pollutant regulation is that requiring a high probability of non-exceedance is likely to carry high costs. The relative contribution of the input variables to critical load uncertainty varied from site to site: any input variable could be important, and thus it was not possible to identify variables as likely targets for research into narrowing uncertainties. Sites where a number of good measurements of input parameters were available had lower uncertainties, so use of in situ measurement could be a valuable way of reducing critical load uncertainty at particularly valuable or disputed sites. From a restricted number of samples, uncertainties in heathland critical loads appear comparable to those of coniferous forest, and nutrient nitrogen critical loads to those of acidity. It was important to include correlations between input variables in the Monte Carlo analysis, but choice of statistical distribution type was of lesser importance. Overall, the analysis provided objective support for the continued use of critical loads in policy development.


Assuntos
Ecossistema , Monitoramento Ambiental/métodos , Poluentes do Solo/análise , Incerteza , Chuva Ácida/análise , Modelos Teóricos , Método de Monte Carlo , Nitrogênio/análise , Poluentes do Solo/normas , Árvores , Reino Unido , Gerenciamento de Resíduos/estatística & dados numéricos
15.
Tob Control ; 12 Suppl 4: IV16-25, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14645936

RESUMO

OBJECTIVE: To explore relationships between patterns of smoking uptake and social context and attitudinal variables. DESIGN: Cross sectional survey. SETTING: Public schools in Tucson, Arizona and Albuquerque, New Mexico. PARTICIPANTS: 982 children in grades 6-9 (ages 11-15 years). MAIN OUTCOME MEASURES: Items measuring smoking history, nicotine dependence and quit attempts, susceptibility to smoking in the future, smoking norms, use of other tobacco products, attitudes toward smoking, and demographic characteristics. RESULTS: Overall, 43% of children had smoked a cigarette and 57% had never used them. Ever smokers lived in social contexts with more smoking and where smoking was normative. Among never users, 25% are susceptible to smoking; these children have positive attitudes toward smoking, do not feel social pressure to stay off cigarettes, and had more friends who smoked. Among ever users, 36% were currently smoking in the past 30 days. Current users also lived in social context with more smoking and had positive attitudes toward smoking. Most users had tried to stop smoking. Only 9% of current users smoked daily; 29% had not smoked a whole cigarette. Greater cigarette consumption was associated with more favourable attitudes toward smoking. Most of past users were in early uptake: 95% had smoked less than 100 cigarettes but 49% were susceptible to smoking again. CONCLUSIONS: There is promise in differentiating subgroups among the never, past and current use of cigarettes. Susceptibility within each of these groups was associated with similar patterns of attitudes and social context. These patterns in smoking uptake need to be confirmed prospectively.


Assuntos
Fumar/psicologia , Adolescente , Atitude Frente a Saúde , Criança , Estudos Transversais , Feminino , Humanos , Relações Interpessoais , Masculino , Grupo Associado , Autoimagem , Abandono do Hábito de Fumar/psicologia , Meio Social , Tabagismo/psicologia
16.
Clin Rheumatol ; 20(4): 270-2, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11529635

RESUMO

A 52-year-old woman with rheumatoid arthritis treated with low-dose steroids developed bilateral distal tibia and fibula fractures over a 15-month period. Her bone density was within osteopenic levels. Such fractures are an unusual but increasingly recognised complication of rheumatoid disease and its treatment, although there is often diagnostic delay. Bilateral fractures are particularly rare. A high level of clinical suspicion is required for early diagnosis.


Assuntos
Articulação do Tornozelo/diagnóstico por imagem , Artrite Reumatoide/complicações , Fíbula/lesões , Fraturas Espontâneas/complicações , Fraturas da Tíbia/complicações , Corticosteroides/uso terapêutico , Articulação do Tornozelo/fisiopatologia , Artrite Reumatoide/diagnóstico por imagem , Artrite Reumatoide/tratamento farmacológico , Densidade Óssea , Moldes Cirúrgicos , Densitometria , Relação Dose-Resposta a Droga , Terapia de Reposição de Estrogênios , Feminino , Fíbula/diagnóstico por imagem , Seguimentos , Fraturas Espontâneas/diagnóstico por imagem , Fraturas Espontâneas/terapia , Humanos , Pessoa de Meia-Idade , Osteoporose/complicações , Osteoporose/diagnóstico , Osteoporose/tratamento farmacológico , Medição da Dor , Radiografia , Medição de Risco , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/terapia
17.
Environ Sci Technol ; 35(23): 4668-74, 2001 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-11770769

RESUMO

A new method for the analysis and display of the effect of emissions controls on visibility is applied to conditions in southern California. An advanced mechanistic air quality model that represents airborne particles as a source-oriented external mixture first is used to track emissions source contributions to the size distribution and chemical composition of airborne particles at Claremont, CA, under heavy smog conditions. The resulting description of the aerosol is used in a Mie scattering calculation to determine the magnitude and particle size dependence of light scattering and absorption in the atmosphere. The resulting light scattering and absorption coefficient values are supplied to an image processing-based visibility model that creates full color representations of the appearance of the local terrain in the presence of the specified level of air pollution based on satellite-generated landscape images. By linking these models, a direct connection is established between source emissions and resulting visual air quality. The composite modeling system then is used to studythe effectthat different emissions control strategies would have on visibility in southern California. An aggressive program of 92 specific emissions control measures that include primary particle controls plus controls on reactive gases that act as secondary aerosol precursors would more than double visual range at Claremont under the 1987 historical conditions studied. Synthetic landscape images show that the mountains to the north of Claremont that are not visible at a range of 10 km under base-case conditions would be visible if the emissions controls described above were applied.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Smog/análise , Absorção , Aerossóis/análise , California , Monitoramento Ambiental , Luz , Tamanho da Partícula
18.
Biochem Biophys Res Commun ; 276(3): 1056-61, 2000 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-11027589

RESUMO

The familial form of amyotrophic lateral sclerosis is caused by mutations in the SOD1 gene encoding the cytosolic antioxidant enzyme Cu,Zn superoxide dismutase. Although there is no clear correlation between disease and dismutating catalytic activity among the various disease-associated SOD1 alleles, all of the known missense mutations significantly alter the half-life of the encoded polypeptides. Using transient transfection studies in mammalian cells, it was demonstrated that a frameshift mutation in SOD1 which results in a truncated polypeptide is similarly destabilized. Using an epitope-tagging strategy to discriminate between mutant and wild-type SOD1 polypeptides, no evidence for dominant effects on polypeptide stability was detected, including that of a positive effect of the wild-type on mutant SOD1 polypeptides or that of a negative effect of mutant on wild-type SOD1 polypeptides. These experiments thus favor a non-catalytic role of mutant forms of SOD1 in disease progression.


Assuntos
Genes Dominantes/genética , Mutação/genética , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Regiões 5' não Traduzidas/genética , Animais , Western Blotting , Linhagem Celular , Cricetinae , Estabilidade Enzimática , Regulação Enzimológica da Expressão Gênica , Peptídeos/química , Peptídeos/genética , Peptídeos/metabolismo , Fenótipo , Proteínas Recombinantes de Fusão , Superóxido Dismutase/química , Transfecção
19.
Health Commun ; 12(3): 261-75, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10938916

RESUMO

A series of sun safety messages containing highly intense language and deductive logical style achieved the most immediate compliance by parents, particularly when they intended to improve protection. Inductive messages were more successful when no intentions existed (D. B. Buller, Borland, & Burgoon, 1998; D. B. Buller et al., 2000). Interviewers recontacted 568 parents during the winter following message dissemination and assessed solar protection. A 2 (language intensity) x 2 (logical style) x 3 (behavioral intention) x 2 (person) mixed-model analysis of variance showed that parents receiving high-intensity, deductive messages reported the most improved solar protection and improvement was greatest when parents intended to improve protection. Over the long term, high language intensity may reinforce decisions to take preventive action and does not appear to provoke psychological reactance or resistance to these highly directive messages.


Assuntos
Educação em Saúde/métodos , Neoplasias Induzidas por Radiação/prevenção & controle , Pais/educação , Comunicação Persuasiva , Neoplasias Cutâneas/prevenção & controle , Raios Ultravioleta/efeitos adversos , Análise de Variância , Distribuição de Qui-Quadrado , Criança , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Entrevistas como Assunto , Masculino , Neoplasias Induzidas por Radiação/etiologia , Psicolinguística , Fatores de Risco , Neoplasias Cutâneas/etiologia
20.
Prev Med ; 30(2): 103-13, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10656838

RESUMO

BACKGROUND: Even though people are informed about skin cancer prevention, they do not always comply with prevention advice. From Language Expectancy Theory, it was predicted that messages with high language intensity would improve compliance with sun safety recommendations and that this effect would be enhanced with deductive argument style. METHODS: Parents (N = 841) from a pediatric clinic and elementary schools received sun safety messages (newsletters, brochures, tip cards) by mail that varied in language intensity and logical style. Effects on attitudes and behavior were tested in a pretest-posttest factorial design. RESULTS: As hypothesized, parents receiving messages with high- as opposed to low-intensity language complied more with sun safety advice. Messages with highly intense language were more persuasive when the arguments were formatted in a deductive style; low language intensity was more persuasive in inductively styled messages. CONCLUSIONS: By carefully adjusting messages features, health professionals can obtain further compliance beyond that produced by educating people about health risks and creating favorable attitudes and self-efficacy expectations. Highly intense language may be a good general strategy in prevention messages and works better when conclusions and recommendations are offered explicitly to recipients, especially when advice is aimed at reducing their personal risk.


Assuntos
Assertividade , Educação em Saúde/métodos , Neoplasias Induzidas por Radiação/prevenção & controle , Pais/educação , Enquadramento Psicológico , Neoplasias Cutâneas/prevenção & controle , Raios Ultravioleta/efeitos adversos , Criança , Pré-Escolar , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Neoplasias Induzidas por Radiação/etiologia , Comunicação Persuasiva , Psicolinguística , Fatores de Risco , Neoplasias Cutâneas/etiologia
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