Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Data ; 10(1): 258, 2023 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-37156773

RESUMO

Records of beach morphologic change and concurrent hydrodynamic forcing are needed to understand how coastlines in different environments change over time. This submission contains data for the period 2006 to 2021, for two contrasting macrotidal environments in southwest England: (i) cross-shore dominated, dissipative, sandy Perranporth Beach, Cornwall; and (ii) longshore-dominated, reflective gravel beaches within Start Bay, Devon. Data comprise monthly to annual beach profile surveys, annual merged topo-bathymetries, in addition to observed and numerically modelled wave and water levels. These data provide a valuable resource for modelling the behaviour of coastal types not covered by other currently available datasets.

2.
Cont Shelf Res ; 245: 104794, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35719127

RESUMO

The global COVID-19 pandemic has seen extended lockdowns, isolation periods and travel restrictions across many countries around the world since early 2020. Some countries, such as Australia and New Zealand, closed their international borders in early 2020 preventing researchers travelling to other parts of the world. To facilitate the exposure of our students' work, and for them to meet international researchers, as well as foster a sense of coastal community, we started a zoominar series (seminars via Zoom) in April 2020. The Coast2Coast zoominar series had therefore humble origins but we soon discovered that there was an appetite for more widely sharing science across the coastal research disciplines. The Coast2Coast zoominar grew rapidly, attracting researchers from many countries around the world who presented and attended fortnightly online seminars. In just one year and a half we had 38 presentations with roughly 1900 attendees, creating a sense of community and belonging for the researchers involved. In early 2021, two of the co-authors, Giovanni (GC) and Ana (AVC) decided to expand and take this sense of community further creating the Coast2Cast podcast series, where researchers are asked research and non-research questions. In only 7 months, the podcasts have attracted more than 3700 listeners. Importantly, while the main prerequisite was high-quality and impactful research, diversity and inclusion were also a priority in selecting and inviting speakers for the zoominars and guests for the podcast. Importantly, our survey results suggest that there is a place for online events similar to Coast2Coast and Coast2Cast in a pandemic-free future, and that the coastal community involved has greatly benefited from such initiatives.

3.
Earths Future ; 9(5): e2020EF001625, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34222554

RESUMO

Improved understanding of how our coasts will evolve over a range of time scales (years-decades) is critical for effective and sustainable management of coastal infrastructure. A robust knowledge of the spatial, directional and temporal variability of the inshore wave climate is required to predict future coastal evolution and hence vulnerability. However, the variability of the inshore directional wave climate has received little attention, and an improved understanding could drive development of skillful seasonal or decadal forecasts of coastal response. We examine inshore wave climate at 63 locations throughout the United Kingdom and Ireland (1980-2017) and show that 73% are directionally bimodal. We find that winter-averaged expressions of six leading atmospheric indices are strongly correlated (r = 0.60-0.87) with both total and directional winter wave power (peak spectral wave direction) at all studied sites. Regional inshore wave climate classification through hierarchical cluster analysis and stepwise multi-linear regression of directional wave correlations with atmospheric indices defined four spatially coherent regions. We show that combinations of indices have significant skill in predicting directional wave climates (R 2  = 0.45-0.8; p < 0.05). We demonstrate for the first time the significant explanatory power of leading winter-averaged atmospheric indices for directional wave climates, and show that leading seasonal forecasts of the NAO skillfully predict wave climate in some regions.

4.
Ned Tijdschr Tandheelkd ; 121(1): 19-24, 2014 Jan.
Artigo em Holandês | MEDLINE | ID: mdl-24552069

RESUMO

It is well known that the dental occlusion can influence the activity of the masticatory muscles. However, a simple, reproducable and predictable relationship has not yet been found. Due to variability between different subjects, the use of absolute electromyographic values is unlikely to help dentists with the diagnostics of temporomandibular disfunction and the possible relationship with the occlusion. Possibly however, interest should center on intraindividual change in activity patterns, when we want to learn more about the effects of the dental occlusion in pathological situations. In recent years limited atttention has focused on the asymmetry ofjaw muscle activtiy and consequently little additional information on this aspect is presently available.


Assuntos
Má Oclusão/fisiopatologia , Músculos da Mastigação/fisiologia , Músculos da Mastigação/fisiopatologia , Eletromiografia , Humanos , Mastigação
5.
J Chem Phys ; 128(11): 114317, 2008 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-18361581

RESUMO

Gerade-ungerade symmetry breaking in HD for the bound states supported by the shallow outer I' (1)Pi(g) potential is studied theoretically. By clarifying the asymptotic behavior of the relevant nonadiabatic couplings among the stats correlating to the n=2 dissociation limit, simple two-state (for f-parity) and three-state (for e-parity) approximations are formulated. They reproduce binding energies in very good agreement with recent spectroscopic measurements. Comparisons with the calculations based on a single model potential are presented and the dependence of the results on the used ab initio Born-Oppenheimer (clamped nuclei) potentials is discussed.

6.
J Chem Phys ; 126(3): 034310, 2007 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-17249874

RESUMO

The authors investigate the use of absorbing potentials and discrete variable representation grid methods in multichannel time-independent scattering calculations. An exactly solvable, coupled-two-channel problem involving square-well potentials is used to assess the quality of numerical results. Special emphasis is given to the description of scattering resonances and near-threshold regions. Numerical treatment of close vicinities of thresholds requires the introduction of nonequidistant grids through a mapping procedure of the scattering coordinate.

7.
J Chem Phys ; 124(9): 94303, 2006 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-16526853

RESUMO

We investigate the use of complex absorbing potentials for the calculation of partial cross sections in multichannel photofragmentation processes. An exactly solvable, coupled-two-channel problem involving square-well potentials is used to compare the performance of various types of absorbing potentials. Special emphasis is given to the near-threshold regions and the conditions under which the numerical results are able to reproduce the Wigner threshold laws. It was found that singular, transmission-free absorbing potentials perform better than those of power or polynomial form.

8.
J Chem Phys ; 122(4): 44108, 2005 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-15740236

RESUMO

We combine the Lanczos algorithm with the absorbing-potential method, implemented in a discrete variable representation to calculate the near-threshold photodissociation cross sections of CH+. The method is iterative, based on a continued fraction representation of the Green function and avoids any explicit matrix diagonalization. A very good agreement is found with experiment and close-coupling calculations.

9.
J Hand Surg Am ; 25(5): 984-5, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11040322
10.
Science ; 289(5477): 300-3, 2000 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-10894778

RESUMO

The spindle checkpoint was characterized in meiosis of budding yeast. In the absence of the checkpoint, the frequency of meiosis I missegregation increased with increasing chromosome length, reaching 19% for the longest chromosome. Meiosis I nondisjunction in spindle checkpoint mutants could be prevented by delaying the onset of anaphase. In a recombination-defective mutant (spo11Delta), the checkpoint delays the biochemical events of anaphase I, suggesting that chromosomes that are attached to microtubules but are not under tension can activate the spindle checkpoint. Spindle checkpoint mutants reduce the accuracy of chromosome segregation in meiosis I much more than that in meiosis II, suggesting that checkpoint defects may contribute to Down syndrome.


Assuntos
Segregação de Cromossomos/fisiologia , Meiose/fisiologia , Saccharomycetales/fisiologia , Fuso Acromático/fisiologia , Fenômenos Biomecânicos , Cromossomos Fúngicos , Síndrome de Down/genética , Endodesoxirribonucleases , Esterases/genética , Cinetocoros/fisiologia , Meiose/genética , Mutação , Não Disjunção Genética , Recombinação Genética , Saccharomycetales/genética , Esporos Fúngicos
13.
Genomics ; 35(1): 109-17, 1996 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-8661111

RESUMO

Despite several lines of evidence suggesting that common chromosomal fragile sites are biologically important as hot spots for recombination, their structure remains unknown. We showed previously that the plasmid pSV2neo preferentially integrates into bands containing fragile sites in cells transfected under conditions of fragile site induction. Here we report the isolation and characterization of the DNA sequences from two such independent integrations into 3p14.2, a common fragile site (FRA3B). These FRA3B region sequences were shown to lie within a 1330-kb YAC, 850A6, approximately 350 kb telomeric of the breakpoint of t(3;8), a constitutional rearrangement. The two integration sites are 10 kb apart, but each integration is associated with a deletion. We have constructed a partial genomic contig of the integration sites and deleted regions spanning approximately 85 kb. Analysis of the DNA sequences immediately surrounding the plasmid integrations revealed no known coding sequences or repeat structures resembling the (CGG)n motif characteristic of the rare fragile sites. In addition, by Southern blotting analysis, none of the phage clones isolated from the FRA3B region were found to contain CGG repeats. Fluorescence in situ hybridization analysis of genomic clones from this contig to metaphase cells induced to express breaks demonstrated hybridization adjoining the chromosome breaks, and occasionally the hybridization signal spanned the break. The results imply that breakage occurs at variable positions within a large region (at least on the order of 85 kb). Together, these data suggest that the structure of FRA3B differs from that of rare fragile sites.


Assuntos
Fragilidade Cromossômica , Cromossomos Humanos Par 3/genética , DNA/genética , Afidicolina/farmacologia , Sequência de Bases , Southern Blotting , Sítios Frágeis do Cromossomo , Passeio de Cromossomo , Cromossomos Artificiais de Levedura/genética , Cromossomos Humanos Par 3/efeitos dos fármacos , Clonagem Molecular , Eletroforese em Gel de Campo Pulsado , Inibidores Enzimáticos/farmacologia , Vetores Genéticos/genética , Humanos , Hibridização in Situ Fluorescente , Dados de Sequência Molecular , Inibidores da Síntese de Ácido Nucleico , Recombinação Genética , Deleção de Sequência , Repetições de Trinucleotídeos
14.
Genetics ; 138(1): 47-60, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8001793

RESUMO

The meiosis-specific yeast gene SPO13 has been previously shown to be required to obtain two successive divisions in meiosis. We report here that vegetative expression of this gene causes a CDC28-dependent cell-cycle arrest at mitosis. Overexpression of SPO13 during meiosis causes a transient block to completion of the meiosis I division and suppresses the inability of cdc28ts strains to execute meiosis II. The spo13 defect can be partially suppressed by conditions that slow progression of the first meiotic division. Based on the results presented below, we propose that SPO13 acts as a meiotic timing function by transiently blocking progression through the meiosis I division, thereby allowing (1) coordination of the first division with assembly of the reductional segregation apparatus, and (2) subsequent entry into a second round of segregation to separate replicated sister chromatids without an intervening S-phase.


Assuntos
Genes Fúngicos , Meiose/genética , Mitose/genética , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Ciclo Celular/genética , Núcleo Celular/ultraestrutura , Clonagem Molecular , Expressão Gênica , Modelos Genéticos , Saccharomyces cerevisiae/crescimento & desenvolvimento
15.
J Oral Rehabil ; 21(1): 67-76, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8133390

RESUMO

UNLABELLED: The electromyographic (EMG) activity of the masseter and the anterior temporalis muscles were compared between 60 healthy controls and 61 myogenous craniomandibular disorder (CMD) patients. Subjects were asked to clench at 10% and at 50% of their maximum voluntary clenching level. The effects of CMD, age and gender were statistically analysed with the use of the analysis of covariance. The correlations between EMG asymmetries and the lateral slide from the retruded contact position to the intercuspal position and the asymmetry in the number of post-canine tooth contacts between the left and the right side were investigated. The CMD patients showed lower masseter EMG activities than the controls, whereas the anterior temporalis EMG activity was not different between the two groups. The activity index, relating the anterior temporalis EMG activity to the activity of the masseter muscles, confirmed the presence of a relatively high temporalis activity in the CMD group. No significant differences were found in the EMG asymmetries between the controls and the CMD patients. Males showed higher masticatory EMG activities than females. These gender effects were significant for the anterior temporalis at the 10% and 50% level and for the masseter muscle at the 10% level. The anterior temporalis EMG activity declined with age. No age related effects were observed in the masseter EMG. The lateral slide was larger and more prevalent in the CMD group. A significant correlation between the lateral slide and the anterior temporalis EMG was found for the CMD group at the 10% level. No correlation was found between the EMG asymmetry and the asymmetries in post-canine tooth contacts. IN CONCLUSION: significant CMD, age and gender effects were observed in the masticatory EMG activities of a group of myogenous CMD patients and a control group.


Assuntos
Força de Mordida , Transtornos Craniomandibulares/fisiopatologia , Músculos da Mastigação/fisiopatologia , Adolescente , Adulto , Fatores Etários , Oclusão Dentária Central , Eletromiografia , Feminino , Humanos , Registro da Relação Maxilomandibular , Masculino , Músculo Masseter/fisiopatologia , Pessoa de Meia-Idade , Contração Muscular , Análise de Regressão , Estudos Retrospectivos , Fatores Sexuais , Músculo Temporal/fisiopatologia
16.
Curr Opin Cell Biol ; 5(2): 219-25, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8389567

RESUMO

Meiosis can be viewed both as a process of cell differentiation and as a modification of the mitotic cell cycle. Here we describe recent progress in defining a variety of regulatory mechanisms that govern the meiotic divisions. Studies in the yeast Saccharomyces cerevisiae and in higher organisms have led to complementary insights into these controls.


Assuntos
Meiose/genética , Animais , Escherichia coli , Feminino , Masculino , Oogênese , Fosfotransferases , Saccharomyces cerevisiae , Schizosaccharomyces , Espermatogênese
17.
J Dent Res ; 71(2): 372-9, 1992 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1556295

RESUMO

The EMG activities of the masseter muscles and the anterior and posterior parts of the temporalis muscles were investigated in different vertical and sagittal jaw relations. Surface EMG recordings were made. Relative muscle activities were quantified by means of the Activity Index and the Asymmetry Index. Ten subjects with a healthy masticatory system were asked to clench at 10% and 50% of their maximum voluntary clenching level. Registrations were made during clenching in the intercuspal position, on a thin stabilization splint (SSP, 1-2 mm increase of vertical dimension at first molar), on a thick stabilization splint (3 mm thicker at the incisal edge relative to SSP), and on a protrusive re-positioning splint (3 mm protrusive to SSP). The masseter EMG amplitudes were the same for all the jaw positions investigated. However, at the 10% clenching level, the temporalis muscle activity decreased after the vertical dimension was raised and decreased further after the mandible was protrusively positioned (p less than 0.01). An independent function for the posterior and the anterior parts of the temporalis muscle was not found in any of the intermaxillary jaw relations investigated. At the 50% clenching level, a decrease in anterior temporalis muscle activity was observed only with the protrusive position in relation to the other three positions. Also at this level, the index relating the activity of the anterior to that of the posterior part of the temporalis muscle was not different between jaw positions. Raising the vertical dimension and protrusive positioning of the mandible decrease the activity of the temporalis muscles. This may be a factor related to the therapeutic effect of the stabilization splint in the treatment of craniomandibular disorder patients.


Assuntos
Oclusão Dentária , Má Oclusão/fisiopatologia , Músculos da Mastigação/fisiologia , Dimensão Vertical , Adulto , Análise de Variância , Relação Central , Eletromiografia , Feminino , Humanos , Masculino , Músculo Masseter/fisiologia , Contração Muscular , Reprodutibilidade dos Testes , Contenções , Músculo Temporal/fisiologia
18.
Proc Natl Acad Sci U S A ; 87(23): 9406-10, 1990 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2123556

RESUMO

The SPO13 gene, required for meiosis I segregation in Saccharomyces cerevisiae, produces two developmentally regulated transcripts (1.0 and 1.4 kilobases) that differ in length at their 5' ends. The shorter transcript is sufficient to complement the spo13-1 mutation and contains a major open reading frame encoding a highly basic protein of 33.4 kilodaltons. A fragment upstream (-170 to -8) of the open reading frame confers meiosis-specific transcription on a spo13-HIS3 fusion. Deletions at the 5' end of spo13-lacZ fusions define a region between -140 and -80 that is essential for meiosis-specific expression. This region acts in an orientation-independent manner and is responsive to the MAT-RME regulatory cascade. It contains a 10-base-pair sequence, TAGCCGCCGA, found in a number of meiosis-specific genes, that appears to be required for SPO13 expression. This sequence is identical to URS1, a ubiquitous mitotic repressor element.


Assuntos
Genes Fúngicos , Regiões Promotoras Genéticas , Saccharomyces cerevisiae/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA Fúngico/genética , Meiose , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Plasmídeos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/fisiologia , Homologia de Sequência do Ácido Nucleico , Esporos Fúngicos/fisiologia , beta-Galactosidase/genética , beta-Galactosidase/metabolismo
19.
Oral Surg Oral Med Oral Pathol ; 70(4): 414-9, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2216378

RESUMO

Diffuse sclerosing osteomyelitis of the mandible is a disease of unknown etiology. The clinical and radiographic findings suggest an infectious origin, but bacteriologic and histologic findings do not support this concept. Analysis of clinical symptoms, localization of the condition, and posttreatment findings in a group of 27 patients suggest a chronic tendoperiostitis due to muscular overuse as an etiologic factor in diffuse sclerosing osteomyelitis of the mandible. This hypothesis was supported by the initial results of muscle relaxation treatment in 13 of these patients.


Assuntos
Doenças Mandibulares/etiologia , Músculos da Mastigação/fisiopatologia , Músculos do Pescoço/fisiopatologia , Osteomielite/etiologia , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Doenças Mandibulares/terapia , Pessoa de Meia-Idade , Contração Muscular , Osteomielite/terapia , Periostite/complicações , Terapia de Relaxamento , Esclerose/etiologia
20.
J Hand Surg Am ; 15(2): 309-15, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2324463

RESUMO

To demonstrate whether revascularization could be surgically induced in avascular bone the femoral heads of female albino rats were excised and drilled through and through. The femoral heads were then placed in the opposite thigh and by use of microvascular techniques the femoral artery was divided and lengthened with a 1 cm artery or vein graft, and reanastomosed after passing one end through the drilled hole in the transplanted femoral head. Arterial blood flowed through the graft within the drilled femoral head on its way to its normal distribution down the leg. Technetium 99m MDP methylene diphosphate, tetracycline labeling, latex injection, and histologic review were used to demonstrate new vessel growth. All grafts patent at the end of the experiment were associated with tetracycline labeling, positive technetium 99m methylene diphosphate counts and latex-filled vessels in the matrix of the femoral heads. Histologically the vascularized femoral heads showed evidence of neovascularization and new bone formation.


Assuntos
Cabeça do Fêmur/irrigação sanguínea , Microcirurgia/métodos , Anastomose Cirúrgica/métodos , Animais , Desenvolvimento Ósseo , Feminino , Artéria Femoral/cirurgia , Cabeça do Fêmur/anatomia & histologia , Cabeça do Fêmur/transplante , Ratos , Medronato de Tecnécio Tc 99m , Tetraciclina/metabolismo , Grau de Desobstrução Vascular
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...