146 research outputs found

    The fetch dependency of small-scale air-sea interaction processes at low to moderate wind speeds

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    The water sided mass boundary layer at the air-sea interface is a sublayer of the viscous boundary layer and acts as the bottle neck for air-sea gas transport. The dominant transport mechanism of the mass boundary layer is molecular diffusion. For low to moderate wind speeds, the main mechanisms occurring in the mass boundary layer are the upwelling of horseshoe vortices, the development of along wind streaks, and the so called microscale breaking, a breaking of the wave crests without bubble entrainment. This thesis investigates the development of these mechanisms in dependence of fetch and wind speed at the Aeolotron wind wave facility, Heidelberg. The collocated and synchronized visualization techniques boundary layer imaging, active thermography, and wave slope imaging enable a unique set of data by providing insight into the turbulent processes taking place in the mass boundary layer and their interaction with wind waves. Three different fetch dependent regimes could be identified that each contribute differently to air-sea heat exchange: a laminar regime with no wind waves, an overshoot regime for dominant gravity wavelengths smaller than 13 cm, and a declining regime for larger wavelengths. Additionally, a further step has been taken in understanding the cause of the microscale breaking mechanism. The initial disturbance is an accumulation of the mass boundary layer thickness in the trough of the parasitic capillary waves with its spontaneous release initiating the microscale breaking

    A sensitive LC-MS/MS method for isomer separation and quantitative determination of 51 pyrrolizidine alkaloids and two tropane alkaloids in cow's milk

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    1,2-Unsaturated pyrrolizidine alkaloids (PA), their corresponding N-oxides (PANO), and tropane alkaloids (TA) are toxic secondary plant metabolites. Their possible transfer into the milk of dairy cows has been studied in feeding trials;however, only few data on the occurrence of these toxins in milk are available. In this study, the development of a sensitive analytical approach for the simultaneous detection and quantification of a broad range of 54 PA/PANO as well as of the TA atropine and scopolamine in milk of dairy cows is presented. The method optimisation focused on sensitivity and separation of PA/PANO isomers. Milk samples were extracted using liquid-liquid extraction with aqueous formic acid and n-hexane, followed by a cation-exchange solid-phase extraction for purification. Reversed phase liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis was performed using alkaline solvent conditions. Validation proved low limits of detection and quantification of 0.005 to 0.054 mu g/L and of 0.009 to 0.123 mu g/L, respectively. For 51 of the 54 tested PA/PANO and both TA, the recovery rates ranged from 64 to 127% with repeatability (RSDr) values below 15% at concentration levels of 0.05 and 0.50 mu g/L and below 8% at a concentration level of 3.00 mu g/L. Only three PANO did not match the validation criteria and were therefore regarded as semiquantitative. The final method was applied to 15 milk samples obtained from milk vending stations at farms and from local marketers in Bavaria, Germany. In three of the milk samples, traces of PA were detected

    Proteome changes in autosomal recessive primary microcephaly

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    Background/aim: : Autosomal recessive primary microcephaly (MCPH) is a rare and genetically heterogeneous group of disorders characterized by intellectual disability and microcephaly at birth, classically without further organ involvement. MCPH3 is caused by biallelic variants in the cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2. In the corresponding Cdk5rap2 mutant or Hertwig's anemia mouse model, congenital microcephaly as well as defects in the hematopoietic system, germ cells and eyes have been reported. The reduction in brain volume, particularly affecting gray matter, has been attributed mainly to disturbances in the proliferation and survival of early neuronal progenitors. In addition, defects in dendritic development and synaptogenesis exist that affect the excitation-inhibition balance. Here, we studied proteomic changes in cerebral cortices of Cdk5rap2 mutant mice. Material and methods: : We used large-gel two-dimensional gel (2-DE) electrophoresis to separate cortical proteins. 2-DE gels were visualized by a trained observer on a light box. Spot changes were considered with respect to presence/absence, quantitative variation and altered mobility. Result: : We identified a reduction in more than 30 proteins that play a role in processes such as cell cytoskeleton dynamics, cell cycle progression, ciliary functions and apoptosis. These proteome changes in the MCPH3 model can be associated with various functional and morphological alterations of the developing brain. Conclusion: : Our results shed light on potential protein candidates for the disease-associated phenotype reported in MCPH3

    The construction of viewpoint aspect: the imperfective revisited

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    This paper argues for a constructionist approach to viewpoint Aspect by exploring the idea that it does not exert any altering force on the situation-aspect properties of predicates. The proposal is developed by analyzing the syntax and semantics of the imperfective, which has been attributed a coercer role in the literature as a de-telicizer and de-stativizer in the progressive, and as a de-eventivizer in the so-called ability (or attitudinal) and habitual readings. This paper proposes a unified semantics for the imperfective, preserving the properties of eventualities throughout the derivation. The paper argues that the semantics of viewpoint aspect is encoded in a series of functional heads containing interval-ordering predicates and quantifiers. This richer structure allows us to account for a greater amount of phenomena, such as the perfective nature of the individual instantiations of the event within a habitual construction or the nonculminating reading of perfective accomplishments in Spanish. This paper hypothesizes that nonculminating accomplishments have an underlying structure corresponding to the perfective progressive. As a consequence, the progressive becomes disentangled from imperfectivity and is given a novel analysis. The proposed syntax is argued to have a corresponding explicit morphology in languages such as Spanish and a nondifferentiating one in languages such as English; however, the syntax-semantics underlying both of these languages is argued to be the same

    Decline in the number of patients with meningitis in German hospitals during the COVID-19 pandemic

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    BACKGROUND AND OBJECTIVES: In 2020, a wide range of hygiene measures was implemented to mitigate infections caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In consequence, pulmonary infections due to other respiratory pathogens also decreased. Here, we evaluated the number of bacterial and viral meningitis and encephalitis cases during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: In a multicentre retrospective analysis of data from January 2016 until December 2020, numbers of patients diagnosed with bacterial meningitis and other types of CNS infections (such as viral meningitis and encephalitis) at 26 German hospitals were studied. Furthermore, the number of common meningitis-preceding ear-nose-throat infections (sinusitis, mastoiditis and otitis media) was evaluated. RESULTS: Compared to the previous years, the total number of patients diagnosed with pneumococcal meningitis was reduced (n = 64 patients/year in 2020 vs. n = 87 to 120 patients/year between 2016 and 2019, all p < 0.05). Additionally, the total number of patients diagnosed with otolaryngological infections was significantly lower (n = 1181 patients/year in 2020 vs. n = 1525 to 1754 patients/year between 2016 and 2019, all p < 0.001). We also observed a decline in viral meningitis and especially enterovirus meningitis (n = 25 patients/year in 2020 vs. n = 97 to 181 patients/year between 2016 and 2019, all p < 0.001). DISCUSSION: This multicentre retrospective analysis demonstrates a decline in the number of patients treated for viral and pneumococcal meningitis as well as otolaryngological infections in 2020 compared to previous years. Since the latter often precedes pneumococcal meningitis, this may point to the significance of the direct spread of pneumococci from an otolaryngological focus such as mastoiditis to the brain as one important pathophysiological route in the development of pneumococcal meningitis. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00415-022-11034-w

    Online insomnia treatment-a review

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    Spiegelhalder K, Acker J, Baumeister H, et al. Digitale Behandlungsangebote für Insomnie – eine Übersichtsarbeit. SOMNOLOGIE. 2020;24(4):106-114.Zusammenfassung Digital angebotene psychologische Interventionen gegen Schlafstörungen sind aktuell ein sehr intensiv bearbeitetes Forschungsthema. In dieser Übersichtsarbeit werden Originalarbeiten und Metaanalysen zu diesem Thema zusammengefasst. Hierbei zeigt sich, dass die internetbasierte kognitive Verhaltenstherapie für Insomnie (KVT-I) bei Erwachsenen durchweg sehr effektiv ist mit allenfalls leicht geringeren Effektstärken als die gleiche Behandlung mit physischer Präsenz von Therapeuten und Patienten. Behandlungseffekte zeigen sich dabei auch für sekundäre Outcome-Parameter wie Depressivität, Angst, Fatigue und Lebensqualität. Hingegen lassen die Forschung zur Wirksamkeit der internetbasierten KVT‑I bei Erwachsenen mit komorbiden psychischen Störungen oder körperlichen Erkrankungen sowie die Forschung zur Frage, wieviel Therapeutenkontakt in die Behandlung integriert werden sollte, anscheinend noch keine abschließenden Antworten zu. In diesen Bereichen scheint weitere Forschung notwendig zu sein scheint.Digitally provided psychological interventions for sleep disorders are currently a very intensively researched topic. In this review, original work and meta-analyses are summarized. Thus, it was shown that internet-based cognitive behavioral therapy for insomnia (CBT-I) in adults is consistently very effective, with only slightly reduced effects compared with the same treatment with the physical presence of therapists and patients. Treatment effects are also shown for secondary outcome parameters such as depression, anxiety, fatigue, and quality of life. On the other hand, research on the effectiveness of internet-based CGT-I in adults with comorbid mental disorders or physical illnesses, and on the issue of how much contact with therapists should be integrated into treatment, does not seem to provide any conclusive answers. Further research seems to be needed in these areas

    Gender-Specific Effects of Unemployment on Family Formation: A Cross-National Perspective

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    Quantification of myocardial blood flow with 82Rb positron emission tomography: clinical validation with 15O-water

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    PURPOSE: Quantification of myocardial blood flow (MBF) with generator-produced (82)Rb is an attractive alternative for centres without an on-site cyclotron. Our aim was to validate (82)Rb-measured MBF in relation to that measured using (15)O-water, as a tracer 100% of which can be extracted from the circulation even at high flow rates, in healthy control subject and patients with mild coronary artery disease (CAD). METHODS: MBF was measured at rest and during adenosine-induced hyperaemia with (82)Rb and (15)O-water PET in 33 participants (22 control subjects, aged 30 ± 13 years; 11 CAD patients without transmural infarction, aged 60 ± 13 years). A one-tissue compartment (82)Rb model with ventricular spillover correction was used. The (82)Rb flow-dependent extraction rate was derived from (15)O-water measurements in a subset of 11 control subjects. Myocardial flow reserve (MFR) was defined as the hyperaemic/rest MBF. Pearson's correlation r, Bland-Altman 95% limits of agreement (LoA), and Lin's concordance correlation ρ (c) (measuring both precision and accuracy) were used. RESULTS: Over the entire MBF range (0.66-4.7 ml/min/g), concordance was excellent for MBF (r = 0.90, [(82)Rb-(15)O-water] mean difference ± SD = 0.04 ± 0.66 ml/min/g, LoA = -1.26 to 1.33 ml/min/g, ρ(c) = 0.88) and MFR (range 1.79-5.81, r = 0.83, mean difference = 0.14 ± 0.58, LoA = -0.99 to 1.28, ρ(c) = 0.82). Hyperaemic MBF was reduced in CAD patients compared with the subset of 11 control subjects (2.53 ± 0.74 vs. 3.62 ± 0.68 ml/min/g, p = 0.002, for (15)O-water; 2.53 ± 1.01 vs. 3.82 ± 1.21 ml/min/g, p = 0.013, for (82)Rb) and this was paralleled by a lower MFR (2.65 ± 0.62 vs. 3.79 ± 0.98, p = 0.004, for (15)O-water; 2.85 ± 0.91 vs. 3.88 ± 0.91, p = 0.012, for (82)Rb). Myocardial perfusion was homogeneous in 1,114 of 1,122 segments (99.3%) and there were no differences in MBF among the coronary artery territories (p &gt; 0.31). CONCLUSION: Quantification of MBF with (82)Rb with a newly derived correction for the nonlinear extraction function was validated against MBF measured using (15)O-water in control subjects and patients with mild CAD, where it was found to be accurate at high flow rates. (82)Rb-derived MBF estimates seem robust for clinical research, advancing a step further towards its implementation in clinical routine

    TRY plant trait database – enhanced coverage and open access

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    Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
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