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1.
Hamostaseologie ; 43(6): 440-446, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37442158

RESUMO

INTRODUCTION: Inherited dysfibrinogenemia is a qualitative defect of fibrinogen caused by various mutations among three fibrinogen genes. Dysfibrinogenemia can be associated with an increased risk of thrombosis, bleeding, or both. Here, we report a 36-year-old female with dysfibrinogenemia who experienced two successful pregnancies under thromboprophylaxis after cerebral venous sinus thrombosis (CVST). PATIENTS AND METHODS: In addition to plasmatic coagulation tests, fibrinogen genes FGA, FGB, and FGG were screened using direct genomic DNA sequencing. The structural-functional implications of the detected mutation were analyzed in silico. RESULTS: Inherited dysfibrinogenemia was diagnosed in an index patient after CVST in a risk situation. Anticoagulation with warfarin was stopped after 12 months when the first pregnancy was planned. Pregnancy and spontaneous delivery (2020) was uncomplicated. A second pregnancy was interrupted because of acute cytomegalovirus infection and the third pregnancy was successful in 2022. Pregnancies were accompanied by thromboprophylaxis with enoxaparin 40 mg once daily until 6 weeks postpartum. Substitution of fibrinogen has not become necessary in the index patient so far. Genetic analysis revealed a novel missense mutation (p. Arg510Cys) in the FGA gene ("fibrinogen Bonn") in the index patient, as well as an asymptomatic sister, and their father who experienced recurrent pulmonary embolism. Surface exposure of wild-type Arg510 suggested the mutated Cys510 to form nonnative disulfide bonds with surface-exposed reactive cysteines from other plasma proteins like albumin leading to formation of aggregates and impaired fibrinolysis. CONCLUSIONS: Fibrinogen Bonn might be associated with an increased risk of thrombosis, possibly due to impaired polymerization.


Assuntos
Afibrinogenemia , Hemostáticos , Trombose , Tromboembolia Venosa , Trombose Venosa , Gravidez , Feminino , Humanos , Adulto , Fibrinogênio/genética , Anticoagulantes/uso terapêutico , Tromboembolia Venosa/complicações , Afibrinogenemia/complicações , Afibrinogenemia/genética , Trombose Venosa/complicações , Mutação , Trombose/complicações
2.
HNO ; 70(9): 705-714, 2022 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-35976387

RESUMO

Considering the increasing number of patients suffering from drug-induced coagulation disorders caused by antiplatelet or anticoagulant therapy, the right balance between minimizing the risk of bleeding and the risk of a venous thrombosis or embolism during otorhinolaryngologic (ORL) surgery is becoming increasingly important. According to a recent study, the highest risk of intraoperative bleeding in ORL surgery is associated with transoral tumor surgery, tonsillectomy, thyroidectomy, and glomus tumor surgery. The risk of venous thrombosis or embolism during ORL surgery is estimated to be 1%, and increases to 6% among tumor patients. Currently, there is no general recommendation for perioperative hemostatic management because of the limited available data. In the majority of patients who continue antiplatelet therapy with acetylsalicylic acid (ASS) to prevent thromboembolic events, the perioperative bleeding risk is considered to be acceptable. For patients with dual antiplatelet therapy, surgical procedures should be only performed after adaption of the medication.


Assuntos
Tumor Glômico , Hemostáticos , Anticoagulantes/farmacologia , Anticoagulantes/uso terapêutico , Aspirina , Coagulação Sanguínea , Tumor Glômico/tratamento farmacológico , Humanos , Inibidores da Agregação Plaquetária/farmacologia , Inibidores da Agregação Plaquetária/uso terapêutico
3.
Sci Rep ; 9(1): 2562, 2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30796272

RESUMO

Filarial nematodes modulate immune responses in their host to enable their survival and mediate protective effects against autoimmunity and allergies. In this study, we examined the immunomodulatory capacity of extracts from the human pathogenic filaria Brugia malayi (BmA) on human monocyte responses in a transcriptome-wide manner to identify associated pathways and diseases. As previous transcriptome studies often observed quiescent responses of innate cells to filariae, the potential of BmA to alter LPS driven responses was investigated by analyzing >47.000 transcripts of monocytes from healthy male volunteers stimulated with BmA, Escherichia coli LPS or a sequential stimulation of both. In comparison to ~2200 differentially expressed genes in LPS-only stimulated monocytes, only a limited number of differentially expressed genes were identified upon BmA priming before LPS re-stimulation with only PTX3↓ reaching statistical significance after correcting for multiple testing. Nominal significant differences were reached for metallothioneins↑, MMP9↑, CXCL5/ENA-78↑, CXCL6/GCP-2↑, TNFRSF21↓, and CCL20/MIP3α↓ and were confirmed by qPCR or ELISA. Flow cytometric analysis of activation markers revealed a reduced LPS-induced expression of HLA-DR and CD86 on BmA-primed monocytes as well as a reduced apoptosis of BmA-stimulated monocytes. While our experimental design does not allow a stringent extrapolation of our results to the development of filarial pathology, several genes that were identified in BmA-primed monocytes had previously been associated with filarial pathology, supporting the need for further research.


Assuntos
Brugia Malayi/química , Proteína C-Reativa/biossíntese , Misturas Complexas/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Monócitos/metabolismo , Componente Amiloide P Sérico/biossíntese , Adolescente , Adulto , Animais , Misturas Complexas/química , Perfilação da Expressão Gênica , Humanos , Masculino
4.
Biogeochemistry ; 135(1): 1-34, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-32009689

RESUMO

Continental shelf sediments are globally important for biogeochemical activity. Quantification of shelf-scale stocks and fluxes of carbon and nutrients requires the extrapolation of observations made at limited points in space and time. The procedure for selecting exemplar sites to form the basis of this up-scaling is discussed in relation to a UK-funded research programme investigating biogeochemistry in shelf seas. A three-step selection process is proposed in which (1) a target area representative of UK shelf sediment heterogeneity is selected, (2) the target area is assessed for spatial heterogeneity in sediment and habitat type, bed and water column structure and hydrodynamic forcing, and (3) study sites are selected within this target area encompassing the range of spatial heterogeneity required to address key scientific questions regarding shelf scale biogeochemistry, and minimise confounding variables. This led to the selection of four sites within the Celtic Sea that are significantly different in terms of their sediment, bed structure, and macrofaunal, meiofaunal and microbial community structures and diversity, but have minimal variations in water depth, tidal and wave magnitudes and directions, temperature and salinity. They form the basis of a research cruise programme of observation, sampling and experimentation encompassing the spring bloom cycle. Typical variation in key biogeochemical, sediment, biological and hydrodynamic parameters over a pre to post bloom period are presented, with a discussion of anthropogenic influences in the region. This methodology ensures the best likelihood of site-specific work being useful for up-scaling activities, increasing our understanding of benthic biogeochemistry at the UK-shelf scale.

5.
Mar Pollut Bull ; 114(1): 315-326, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-27745973

RESUMO

Little is known about the fate of subsurface hydrocarbon plumes from deep-sea oil well blowouts and their effects on processes and communities. As deepwater drilling expands in the Faroe-Shetland Channel (FSC), oil well blowouts are a possibility, and the unusual ocean circulation of this region presents challenges to understanding possible subsurface oil pathways in the event of a spill. Here, an ocean general circulation model was used with a particle tracking algorithm to assess temporal variability of the oil-plume distribution from a deep-sea oil well blowout in the FSC. The drift of particles was first tracked for one year following release. Then, ambient model temperatures were used to simulate temperature-mediated biodegradation, truncating the trajectories of particles accordingly. Release depth of the modeled subsurface plumes affected both their direction of transport and distance travelled from their release location, and there was considerable interannual variability in transport.


Assuntos
Hidrocarbonetos/análise , Modelos Teóricos , Campos de Petróleo e Gás , Poluição por Petróleo/análise , Regiões Árticas , Biodegradação Ambiental , Gammaproteobacteria/crescimento & desenvolvimento , Oceanos e Mares , Água do Mar/química , Água do Mar/microbiologia , Movimentos da Água
6.
Hamostaseologie ; 36(Suppl. 2): S34-S38, 2016 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-27824214

RESUMO

Afibrinogenemia represents the rarest form of fibrinogen deficiency. Causative missense mutations occur rarely and may improve the understanding of fibrinogen structure and function. PATIENTS AND METHODS: The propositus was a 26-year-old Argentinian with afibrinogenemia. FGA, FGB and FGG exons and flanking regions were screened by sequencing and the mutant protein was analyzed in silico. RESULTS: A novel missense mutation in the FGB gene (Bbeta Gly272Arg, p.Gly302Arg) was identified. In silico analysis revealed its location in a highly conserved region, which preserves the core fold of the C-terminal beta-chain and is important for proper secretion. A substitution by a positively charged large Arg residue in this area would most likely disturb the core fold by additional interactions with adjacent residues (p.Asp291, p.Asp297, p.Asp311), or by forming of non-native interactions with other proteins, thereby hindering the action of molecular chaperones. Both alternatives would disturb the regular secretion of the beta-chain. CONCLUSIONS: The novel missense mutation in the FGB gene causes afibrinogenemia most probably by affecting the secretion of the fibrinogen beta-chain.


Assuntos
Afibrinogenemia/diagnóstico , Afibrinogenemia/genética , Códon sem Sentido/genética , Fibrinogênio/genética , Hemorragia/diagnóstico , Hemorragia/genética , Adulto , Afibrinogenemia/complicações , Sequência de Bases , Diagnóstico Diferencial , Fibrinogênio/química , Fibrinogênio/ultraestrutura , Predisposição Genética para Doença/genética , Testes Genéticos/métodos , Hemorragia/complicações , Humanos , Masculino , Dados de Sequência Molecular , Doenças Raras/diagnóstico , Doenças Raras/genética , Relação Estrutura-Atividade
7.
Phys Rev E ; 94(3-1): 033208, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27739766

RESUMO

We report on experiments irradiating isolated plastic spheres with a peak laser intensity of 2-3×10^{20}Wcm^{-2}. With a laser focal spot size of 10 µm full width half maximum (FWHM) the sphere diameter was varied between 520 nm and 19.3 µm. Maximum proton energies of ∼25 MeV are achieved for targets matching the focal spot size of 10 µm in diameter or being slightly smaller. For smaller spheres the kinetic energy distributions of protons become nonmonotonic, indicating a change in the accelerating mechanism from ambipolar expansion towards a regime dominated by effects caused by Coulomb repulsion of ions. The energy conversion efficiency from laser energy to proton kinetic energy is optimized when the target diameter matches the laser focal spot size with efficiencies reaching the percent level. The change of proton acceleration efficiency with target size can be attributed to the reduced cross-sectional overlap of subfocus targets with the laser. Reported experimental observations are in line with 3D3V particle in cell simulations. They make use of well-defined targets and point out pathways for future applications and experiments.

8.
Sci Rep ; 6: 26095, 2016 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-27180728

RESUMO

On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850 m water depth) encompassing two spatial scales (1-10 km(2)) on and adjacent to a small abyssal hill (240 m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km(-2) (95% CI: 601-844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km(-2) respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed.


Assuntos
Biodiversidade , Gadiformes/fisiologia , Biologia Marinha , Animais , Ecossistema , Oceanos e Mares , Fotografação , Inquéritos e Questionários
9.
Aquat Geochem ; 22(5): 401-417, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-32355451

RESUMO

Long time-series studies are critical to assessing impacts of climate change on the marine carbon cycle. A 27-year time-series study in the abyssal northeast Pacific (Sta. M, 4000 m depth) has provided the first concurrent measurements of sinking particulate organic carbon supply (POC flux) and remineralization by the benthic community. Sediment community oxygen consumption (SCOC), an estimate of organic carbon remineralization, was measured in situ over daily to interannual periods with four different instruments. Daily averages of SCOC ranged from a low of 5.0 mg C m-2 day-1 in February 1991 to a high of 31.0 mg C m-2 day-1 in June 2012. POC flux estimated from sediment trap collections at 600 and 50 m above bottom ranged from 0.3 mg C m-2 day-1 in October 2013 to 32.0 mg C m-2 day-1 in June 2011. Monthly averages of SCOC and POC flux correlated significantly with no time lag. Over the long time series, yearly average POC flux accounted for 63 % of the estimated carbon demand of the benthic community. Long time-series studies of sediment community processes, particularly SCOC, have shown similar fluctuations with the flux of POC reaching the abyssal seafloor. SCOC quickly responds to changes in food supply and tracks POC flux. Yet, SCOC consistently exceeds POC flux as measured by sediment traps alone. The shortfall of ~37 % could be explained by sediment trap sampling artifacts over decadal scales including undersampling of large sinking particles. High-resolution measurements of SCOC are critical to developing a realistic carbon cycle model for the open ocean. Such input is essential to evaluate the impact of climate change on the oceanic carbon cycle, and the long-term influences on the sedimentation record.

10.
Hamostaseologie ; 35 Suppl 1: S32-5, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26540128

RESUMO

UNLABELLED: Inherited mild factor XIII deficiency belongs to one of the most underdiagnosed bleeding disorders so far. This is, because most patients do not develop bleeding complications in daily life. Patient, methods: A man (age: 64 years) without a history of bleeding presented with painful swelling of neck, weight loss, anemia and episodic bleeding from the right tonsil necessitating tonsillectomy. Histologic and immunohistochemical evaluation revealed cytokeratin-positive epitheloid angiosarcoma. Blood coagulation status showed significantly elevated D-dimer and decreased FXIII levels (FXIII-activity 35%, FXIIIA-Ag 16-26%). Plasma mixing studies excluded neutralizing antibodies against FXIII. RESULTS: A novel heterozygous F13A1 gene nonsense mutation (p.Glu103Ter, c.307G>T) was found confirming heterozygous FXIII-A deficiency. The same mutation was detected in two further asymptomatic relatives. For further clinical management the patient was transfused with FXIII-concentrate and showed an adequate increase of FXIII ruling out FXIII deficiency to be induced by increased turnover. Despite this haemostatic management and antifibrinolytic treatment the patient had to undergo several revisions due to delayed, Hb relevant bleeding after cervical lymph nodes extirpation and resection of tonsil. Two chemotherapy cycles with paclitaxel and palliative radiotherapy of the neck area were performed, but the patient died unfortunately two months after diagnosis. CONCLUSIONS: It is a unique case showing the combination of a highly aggressive angiosarcoma and presence of inherited FXIII deficiency. It is also a rare example demonstrating the benefit of FXIII genotyping besides the expected acquired FXIII deficiency possibly due to neoplasm induced increased consumption by elevated crosslinking of fibrin fibers.


Assuntos
Deficiência do Fator XIII/diagnóstico , Deficiência do Fator XIII/genética , Fator XIII/genética , Neoplasias de Cabeça e Pescoço/complicações , Hemorragia/etiologia , Perda de Heterozigosidade/genética , Diagnóstico Diferencial , Deficiência do Fator XIII/congênito , Fator XIIIa/genética , Evolução Fatal , Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/terapia , Hemorragia/diagnóstico , Hemorragia/prevenção & controle , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
11.
Mar Biol ; 162(3): 617-624, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25705055

RESUMO

Changes in habitat-forming organisms can have complex consequences for associated species. Sessile epibenthic glass "plate" sponges (Porifera: Hexactinellida) are conspicuous inhabitants of soft-sediment abyssal areas and their siliceous spicules create persistent spicule patches on the seafloor. Sponge spicule patch density, spatial dispersion, and percent cover were examined over a seven-year period (2006-2013) using remotely operated vehicle videos from Station M in the abyssal northeast Pacific (50˚00N, 123˚00W, ~4,000 m depth). There was an apparent large increase in newly dead plate sponges in February 2007 compared with December 2006, with this trend continuing through June 2007 (mean 0.03 % cover increasing to 0.33 %). A second increase in mean percent cover of dead plate sponges occurred from May 2011 (0.24 %) through June 2012 (0.60 %). Among the 28 megafaunal taxa occurring in association with the patches, the distributions of three taxa [two sponge taxa (Porifera) and brittle stars (Ophiuroidea)] suggested selectivity for the sponge spicule patches. The community structure of visible megafauna within sponge spicule patches was different when compared with that outside the patches suggesting that the sponges, after death, provide preferred habitat patches for certain benthic megafauna. These findings indicate that sponge spicule patches contribute to habitat heterogeneity in space and time.

12.
Artigo em Inglês | MEDLINE | ID: mdl-25353922

RESUMO

The Landau-Lifshitz equation provides an efficient way to account for the effects of radiation reaction without acquiring the nonphysical solutions typical for the Lorentz-Abraham-Dirac equation. We solve the Landau-Lifshitz equation in its covariant four-vector form in order to control both the energy and momentum of radiating particles. Our study reveals that implicit time-symmetric collocation methods of the Runge-Kutta-Nyström type are superior in accuracy and better at maintaining the mass-shell condition than their explicit counterparts. We carry out an extensive study of numerical accuracy by comparing the analytical and numerical solutions of the Landau-Lifshitz equation. Finally, we present the results of the simulation of particle scattering by a focused laser pulse. Due to radiation reaction, particles are less capable of penetrating into the focal region compared to the case where radiation reaction is neglected. Our results are important for designing forthcoming experiments with high intensity laser fields.


Assuntos
Algoritmos , Modelos Químicos , Análise Numérica Assistida por Computador , Fótons , Radioisótopos/análise , Radioisótopos/química , Simulação por Computador , Matemática/métodos
13.
Nat Commun ; 4: 1763, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23612304

RESUMO

Reflecting light from a mirror moving close to the speed of light has been envisioned as a route towards producing bright X-ray pulses since Einstein's seminal work on special relativity. For an ideal relativistic mirror, the peak power of the reflected radiation can substantially exceed that of the incident radiation due to the increase in photon energy and accompanying temporal compression. Here we demonstrate for the first time that dense relativistic electron mirrors can be created from the interaction of a high-intensity laser pulse with a freestanding, nanometre-scale thin foil. The mirror structures are shown to shift the frequency of a counter-propagating laser pulse coherently from the infrared to the extreme ultraviolet with an efficiency >10(4) times higher than in the case of incoherent scattering. Our results elucidate the reflection process of laser-generated electron mirrors and give clear guidance for future developments of a relativistic mirror structure.

14.
Phys Rev E Stat Nonlin Soft Matter Phys ; 83(3 Pt 2): 036407, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21517604

RESUMO

By the use of two-dimensional particle-in-cell simulations, we clarify the terahertz (THz) radiation mechanism from a plasma filament formed by an intense femtosecond laser pulse. The nonuniform plasma density of the filament leads to a net radiating current for THz radiation. This current is mainly located within the pulse and the first cycle of the wakefield. As the laser pulse propagates, a single-cycle and radially polarized THz pulse is constructively built up forward. The single-cycle shape is mainly due to radiation damping effect.

15.
Phys Rev Lett ; 106(3): 035001, 2011 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-21405278

RESUMO

Recently, much attention has been attracted to the problem of limitations on the attainable intensity of high power lasers [A. M. Fedotov et al., Phys. Rev. Lett. 105, 080402 (2010)]. The laser energy can be absorbed by electron-positron pair plasma produced from a seed by a strong laser field via the development of the electromagnetic cascades. The numerical model for a self-consistent study of electron-positron pair plasma dynamics is developed. Strong absorption of the laser energy in self-generated overdense electron-positron pair plasma is demonstrated. It is shown that the absorption becomes important for a not extremely high laser intensity I ∼ 10(24) W/cm(2) achievable in the near future.


Assuntos
Elétrons , Lasers , Absorção , Método de Monte Carlo
16.
Adv Mar Biol ; 58: 1-95, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20959156

RESUMO

Societal concerns over the potential impacts of recent global change have prompted renewed interest in the long-term ecological monitoring of large ecosystems. The deep sea is the largest ecosystem on the planet, the least accessible, and perhaps the least understood. Nevertheless, deep-sea data collected over the last few decades are now being synthesised with a view to both measuring global change and predicting the future impacts of further rises in atmospheric carbon dioxide concentrations. For many years, it was assumed by many that the deep sea is a stable habitat, buffered from short-term changes in the atmosphere or upper ocean. However, recent studies suggest that deep-seafloor ecosystems may respond relatively quickly to seasonal, inter-annual and decadal-scale shifts in upper-ocean variables. In this review, we assess the evidence for these long-term (i.e. inter-annual to decadal-scale) changes both in biologically driven, sedimented, deep-sea ecosystems (e.g. abyssal plains) and in chemosynthetic ecosystems that are partially geologically driven, such as hydrothermal vents and cold seeps. We have identified 11 deep-sea sedimented ecosystems for which published analyses of long-term biological data exist. At three of these, we have found evidence for a progressive trend that could be potentially linked to recent climate change, although the evidence is not conclusive. At the other sites, we have concluded that the changes were either not significant, or were stochastically variable without being clearly linked to climate change or climate variability indices. For chemosynthetic ecosystems, we have identified 14 sites for which there are some published long-term data. Data for temporal changes at chemosynthetic ecosystems are scarce, with few sites being subjected to repeated visits. However, the limited evidence from hydrothermal vents suggests that at fast-spreading centres such as the East Pacific Rise, vent communities are impacted on decadal scales by stochastic events such as volcanic eruptions, with associated fauna showing complex patterns of community succession. For the slow-spreading centres such as the Mid-Atlantic Ridge, vent sites appear to be stable over the time periods measured, with no discernable long-term trend. At cold seeps, inferences based on spatial studies in the Gulf of Mexico, and data on organism longevity, suggest that these sites are stable over many hundreds of years. However, at the Haakon Mosby mud volcano, a large, well-studied seep in the Barents Sea, periodic mud slides associated with gas and fluid venting may disrupt benthic communities, leading to successional sequences over time. For chemosynthetic ecosystems of biogenic origin (e.g. whale-falls), it is likely that the longevity of the habitat depends mainly on the size of the carcass and the ecological setting, with large remains persisting as a distinct seafloor habitat for up to 100 years. Studies of shallow-water analogs of deep-sea ecosystems such as marine caves may also yield insights into temporal processes. Although it is obvious from the geological record that past climate change has impacted deep-sea faunas, the evidence that recent climate change or climate variability has altered deep-sea benthic communities is extremely limited. This mainly reflects the lack of remote sensing of this vast seafloor habitat. Current and future advances in deep-ocean benthic science involve new remote observing technologies that combine a high temporal resolution (e.g. cabled observatories) with spatial capabilities (e.g. autonomous vehicles undertaking image surveys of the seabed).


Assuntos
Ecossistema , Animais , Mudança Climática , Peixes , Fenômenos Geológicos , Oceanos e Mares , Fatores de Tempo
17.
Proc Natl Acad Sci U S A ; 106(46): 19211-8, 2009 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-19901326

RESUMO

Climate variation affects surface ocean processes and the production of organic carbon, which ultimately comprises the primary food supply to the deep-sea ecosystems that occupy approximately 60% of the Earth's surface. Warming trends in atmospheric and upper ocean temperatures, attributed to anthropogenic influence, have occurred over the past four decades. Changes in upper ocean temperature influence stratification and can affect the availability of nutrients for phytoplankton production. Global warming has been predicted to intensify stratification and reduce vertical mixing. Research also suggests that such reduced mixing will enhance variability in primary production and carbon export flux to the deep sea. The dependence of deep-sea communities on surface water production has raised important questions about how climate change will affect carbon cycling and deep-ocean ecosystem function. Recently, unprecedented time-series studies conducted over the past two decades in the North Pacific and the North Atlantic at >4,000-m depth have revealed unexpectedly large changes in deep-ocean ecosystems significantly correlated to climate-driven changes in the surface ocean that can impact the global carbon cycle. Climate-driven variation affects oceanic communities from surface waters to the much-overlooked deep sea and will have impacts on the global carbon cycle. Data from these two widely separated areas of the deep ocean provide compelling evidence that changes in climate can readily influence deep-sea processes. However, the limited geographic coverage of these existing time-series studies stresses the importance of developing a more global effort to monitor deep-sea ecosystems under modern conditions of rapidly changing climate.


Assuntos
Carbono/metabolismo , Mudança Climática , Ecossistema , Animais , Peixes , Oceanos e Mares
18.
Phys Rev Lett ; 101(22): 225002, 2008 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-19113487

RESUMO

After two decades of experiments with intense fs laser pulses the physical mechanism of collisionless absorption in overdense matter is still not understood. We show that anharmonic resonance in the self-generated plasma potential at a steep ion density profile may represent the leading physical absorption mechanism. Resonance provides for the phase shift of the free electron current which is compulsory for laser beam energy transfer to any medium and is capable of explaining the prompt generation of fast electrons with maximum energies exceeding many times their quiver energy, and the polarization dependence.

19.
Phys Rev Lett ; 100(24): 245001, 2008 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-18643593

RESUMO

Absorption measurements on solid conducting targets have been performed in s and p polarization with ultrashort, high-contrast Ti:sapphire laser pulses at intensities up to 5x10{16}W/cm{2} and pulse duration of 8 fs. The particular relevance of the reported absorption measurements lies in the fact that the extremely short laser pulse interacts with matter close to solid density during the entire pulse duration. A pronounced increase of absorption for p polarization at increasing angles is observed reaching 77% for an incidence angle of 80 degrees . Simulations performed using a 2D particle in cell code show a very good agreement with the experimental data for a plasma profile of L/lambda approximately 0.01.

20.
Dtsch Med Wochenschr ; 132(31-32): 1613-8, 2007 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-17654413

RESUMO

BACKGROUND: Abnormal eating behavior (binge eating) is widespread, yet very often remains undetected in general medical practice because of the secretiveness of the affected person. A screening questionnaire (KFzE, 8 items, range 0-6) was developed to diagnose this specific eating disorder. Questions relating to or implying psychopathological aspects were excluded to avoid any stigmatization. PATIENTS AND METHODS: A partial score (TSc3) was calculated from the ratings of three core symptoms (1. uncontrollable urge to eat; 2. thinking of food; 3. feeling of satiety). In addition, the ratings of five symptoms depicting more nonspecific aspects of eating abnormalities were added to calculate a total score (GSc8). RESULTS: Based on the score values and cut-off points (the latter derived from the frequency distributions of TSc and GSc), patients suffering from bulimia nervosa without overweight or obesity (BN, group I, n = 51, BMI<25 kg/m2) as well as those with binge eating syndrome very often (91%) associated with overweight or obesity (BES, group II, n = 80, BMI>25 kg/m2) were clearly distinguishable from overweight or obese persons without binge eating (group III, n = 70) and healthy female controls (group IV, n = 119). The small differences in the mean scores between patients with BN and those with BES confirm earlier results obtained with other questionnaires. Moreover, results of the BITE questionnaire (Bulimia Investigatory Test Edinburgh), a proven method for diagnosing binge eating from its symptom subscale (30 items), correspond well with the results obtained from the KFzE for both groups of patients. The KFzE shows good psychometric characteristics such as test-retest reliability (0,92) and internal consistency (a= 0,87) DISCUSSION: The described method gives medical practitioners a simple way of screening a large number of patients of normal weight, overweight or obesity who need careful and early evaluation of a previously unrecognized eating disorder. It can be used for ongoing monitoring as well as for following any type of therapeutic approach in persons with binge eating.


Assuntos
Bulimia/diagnóstico , Obesidade/complicações , Vigilância da População/métodos , Inquéritos e Questionários , Adulto , Índice de Massa Corporal , Bulimia/complicações , Estudos de Casos e Controles , Feminino , Humanos , Inquéritos e Questionários/normas
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