80 research outputs found
Northern Hemisphere interdecadal variability: A coupled air-sea mode
A coupled air–sea mode in the Northern Hemisphere with a period of about 35 years is described. The mode was derived from a multicentury integration with a coupled ocean–atmosphere general circulation model and involves interactions of the thermohaline circulation with the atmosphere in the North Atlantic and interactions between the ocean and the atmosphere in the North Pacific.
The authors focus on the physics of the North Atlantic interdecadal variability. If, for instance, the North Atlantic thermohaline circulation is anomalously strong, the ocean is covered by positive sea surface temperature (SST) anomalies. The atmospheric response to these SST anomalies involves a strengthened North Atlantic Oscillation, which leads to anomalously weak evaporation and Ekman transport off Newfoundland and in the Greenland Sea, and the generation of negative sea surface salinity (SSS) anomalies. These SSS anomalies weaken the deep convection in the oceanic sinking regions and subsequently the strength of the thermohaline circulation. This leads to a reduced poleward heat transport and the formation of negative SST anomalies, which completes the phase reversal.
The Atlantic and Pacific Oceans seem to be coupled via an atmospheric teleconnection pattern and the interdecadal Northern Hemispheric climate mode is interpreted as an inherently coupled air–sea mode. Furthermore, the origin of the Northern Hemispheric warming observed recently is investigated. The observed temperatures are compared to a characteristic warming pattern derived from a greenhouse warming simulation with the authors’ coupled general circulation model and also with the Northern Hemispheric temperature pattern associated with the 35-yr climate mode. It is shown that the recent Northern Hemispheric warming projects well onto the temperature pattern of the interdecadal mode under consideration
Komplexität der Umsetzung von Therapiezieländerungen in der Intensivmedizin – Analyse von 169 Entscheidungssituationen auf der operativen Intensivstation
Die Intensivmedizin mit der Aufgabe der Überbrückung der Zeit bis zur Wiederherstellung der körpereigenen Organfunktionen ist heute ein unverzichtbarer Bestandteil der Krankenhausstruktur. Durch die Entwicklung moderner Organersatzverfahren und unbegrenzt erscheinender therapeutischer Möglichkeiten stellt sich die Frage nach der Sinnhaftigkeit uneingeschränkter Maximaltherapie und somit beständig die Frage nach einer Therapiezieländerung bei Patienten mit stark eingeschränkter Prognose. Die Entscheidung über eine Therapiezieländerung ist ein von rechtlichen Vorschriften und ethischen Überlegungen geprägter Prozess, der sich auf die Indikationsstellung durch den Arzt und den Willen des Patienten stützt, und der unter Einbeziehung der Angehörigen erfolgen sollte. Ziel der hier vorliegenden Studie war es, die Komplexität der Umsetzung der Therapiezieländerungen zu analysieren und im Detail zu beschreiben.
Hierfür wurden retrospektiv Daten von 169 verstorbenen Patienten der operativen Intensivstation des Universitätsklinikums Regensburg aus den Jahren 2015 und 2016 in einem zuvor erstellten Case Report Form erfasst und anschließend analysiert. In der Literatur wird meist unterschieden zwischen der Beendigung einer Therapie (withdrawing) und dem Vorenthalten einer Therapie (withholding). Die hier vorliegende Studie untersuchte zudem die Häufigkeit des Reduzierens einer Therapie im Rahmen der Umsetzung der Therapiezieländerung und liefert damit einen weiteren Aspekt.
Bei 169 Verstorbenen, dies entspricht 81,6% aller Verstorbenen, wurde eine Entscheidung zur Therapiezieländerung getroffen. Das Beenden einer oder mehrerer Therapiemaßnahmen (142 (84,0%) Patienten) war häufiger als das Reduzieren (113 (66,9%) Patienten) oder Vorenthalten (82 (48,5%) Patienten) einer oder mehrerer Therapien. Die in absoluten Zahlen am häufigsten vorenthaltene Therapie war die Reanimation. Die sowohl am häufigsten reduzierte als auch beendete Therapie war die Behandlung mit vasoaktiven Substanzen (Katecholaminen). Gemessen an der bestehenden Organunterstützung zum Zeitpunkt der Entscheidung fällt auf, dass die Volumentherapie nur bei 1,2% der Patienten mit bestehender Volumentherapie beendet wurde. Um Aussagen über die Gründe hierfür treffen zu können, bedarf es weiterer Studien im spezifischen Umfeld der Intensivstation.
Die Umsetzung der Therapiezieländerung erfolgte häufig in Schritten. So ging dem Beenden einer Therapie in bis zu zwei Drittel der Fälle das Reduzieren der Therapie voraus. Die erste Maßnahme zur Umsetzung der Therapiezieländerung ist geprägt vom Vorenthalten einer Therapie und die letzte Maßnahme zur Umsetzung der Therapiezieländerung vom Beenden einer Therapiemaßnahme. Ist die erste Maßnahme das Vorenthalten einer Therapie, so ist die Zeit bis zum Tod signifikant länger als beim Reduzieren oder der Beendigung einer Therapie als erste Maßnahme.
Als Grundlage zur Entscheidungsfindung konnte die aussichtslose Prognose und der mutmaßliche Wille der Patienten identifiziert werden. Die Angehörigen waren in den Entscheidungsprozess ausführlich eingebunden, wobei die Anzahl der Angehörigengespräche mit der Dauer des Aufenthalts der Patienten auf der Intensivstation korrelierte. Die enge Einbindung der Angehörigen und die Berücksichtigung des Patientenwillens als Grundlage einer Entscheidung zur Therapiezieländerung geht in dieser Studie mit einer hohen Rate an Entscheidungen zur Therapiezieländerung einher. Inwieweit die Einbindung der Angehörigen und die Berücksichtigung des Patientenwillens für die Häufigkeit der Therapiezieländerung eine Rolle spielen, bedarf weiterer Untersuchung.
In Zusammenschau der Ergebnisse zeigt die hier vorliegende Studie deutlich die Komplexität der Umsetzung der Therapiezieländerung und den daraus folgenden, an den Patienten angepassten Umsetzungsweg. Die Ergebnisse verdeutlichen die zentrale Rolle einer patientenzentrierten Intensivmedizin. Damit stellt sich die Aufgabe an ein Klinikum der Maximalversorgung, wie ein Universitätsklinikum, welches grundsätzlich der Hochleistungsmedizin verschrieben ist, das Konzept best supportive care bereitzustellen, um den Wünschen der Patienten gerecht zu werden
Tratamentos de efluente de processo de polpa quimiotermomecânica CTMP
Pulp and paper sector contributes significantly to Brazilian economy, accordingly to the crescent grow in production of pulp and paper in the last years. Effluent generated in mills of this sector is commonly formed by organic compounds originated from lignin molecules degradation. In general, contaminants are measured through color, chemical oxygen demand (COD), biochemical oxygen demand (BOD), total organic carbon (TOC), lignin compounds, turbidity, solids and phenolic compounds contents. The aim of this study was to run a technically feasible treatment for an effluent from CTMP (chemiothermalmechanical pulping) plant. According to the literature, different methods can be applied for this kind of effluent. Physical-chemical treatment of coagulation-flocculation-sedimentation was performed and the conditions of pH, coagulant type and concentration and settling time were optimized. Coagulant concentration and pH curves verified the best treatment condition, which were: pH 3.0, aluminum sulphate as coagulant, concentration of coagulant at 750 mg.L-1 and settling time of 60 minutes. The removal efficiencies obtained for these condition were 20, 40 and 50% for COD, color and turbidity, respectively. The TOC removal was 78% and toxicity was not changed due to the treatment. For the optimized condition of the treatment, it was testes a high molar mass cationic flocculant, which demonstrated improvements in the removal efficiencies in 10% (average). The effluent treated using the most efficient condition of the physical-chemical treatment passed through a oxidative process – Fenton. In this sense, it was obtained removal of COD and TOC of 51.6 and 78.9%, respectively. Finally, the combined methods lead to a total removal of 74% for turbidity, 53% for color, 61% for COD and 95% for TOC.O setor de celulose e papel contribui significativamente para a economia brasileira, de acordo com o crescimento na produção de celulose e papel nos últimos anos. O efluente gerado em indústria deste setor é comumente formado por compostos orgânicos originados da degradação das moléculas de lignina, que é um dos constituintes básicos da madeira. Em geral, os contaminantes são mensurados através de análises de cor, demanda química de oxigênio (DQO), demanda bioquímica de oxigênio (DBO), carbono orgânico total (COT), teor de compostos lignínicos, turbidez, sólidos, compostos fenólicos e toxicidade. O objetivo deste trabalho foi realizar tratamento de um efluente de planta de polpa quimiotermomecânica CTMP por processos físico-químico e avançado. De acordo com a literatura, diferentes métodos podem ser utilizados para tratamento deste efluente. Tratamento físico-químico de coagulação-floculação-sedimentação foi realizado e as condições de pH, concentração e tipo de coagulante e tempo de sedimentação foram otimizadas. Curvas de pH e concentração de coagulante permitiram verificar que as melhores condições do tratamento, que foram: pH 3,0, sulfato de alumínio como coagulante, concentração do coagulante em 750 mg.L-1 e tempo de sedimentação de 60 minutos. As eficiências de remoção obtidas para esta condição foram 20, 40 e 50% para DQO, cor e turbidez, respectivamente. A eficiência de remoção de COT ficou em 78% e a toxicidade não foi alterada pelo tratamento. Para a condição otimizada do tratamento foi testado o efeito de um floculante catiônico de alta massa molecular, o qual demonstrou melhora nas eficiências de remoção de, em média, 10%. O efluente tratado na melhor condição do tratamento físico-químico foi submetido a um tratamento por processo oxidativo avançado – Fenton. Com este, obteve-se remoção de DQO e COT de 51,6 e 78,9%, respectivamente. Assim a combinação dos métodos permitiu uma remoção total de 74% de turbidez, 53% para cor, 61% para DQO e 95% para COT
Oceanic control of decadal North Atlantic sea level pressure variability in winter
The predictability of winter‐time North Atlantic sea level pressure (SLP) variability has been investigated by means of an ensemble of integrations with an atmospheric general circulation model (AGCM) forced by observed sea surface temperatures (SSTs) for the period 1951–1994. The results imply that the SLP variations on timescales of several years to decades may be predictable, provided the SST anomalies themselves used to drive the AGCM can be predicted. The model, however, suffers from systematic errors, and the simulated centers of action are shifted relative to those observed
DynaMoN: Motion-Aware Fast And Robust Camera Localization for Dynamic NeRF
Dynamic reconstruction with neural radiance fields (NeRF) requires accurate
camera poses. These are often hard to retrieve with existing
structure-from-motion (SfM) pipelines as both camera and scene content can
change. We propose DynaMoN that leverages simultaneous localization and mapping
(SLAM) jointly with motion masking to handle dynamic scene content. Our robust
SLAM-based tracking module significantly accelerates the training process of
the dynamic NeRF while improving the quality of synthesized views at the same
time. Extensive experimental validation on TUM RGB-D, BONN RGB-D Dynamic and
the DyCheck's iPhone dataset, three real-world datasets, shows the advantages
of DynaMoN both for camera pose estimation and novel view synthesis.Comment: 6 pages, 4 figure
A high resolution AGCM study of the El Niño impact on the North Atlantic/European sector
An atmospheric general circulation model (AGCM) sensitivity study has been performed with the ECHAM4 model forced by anomalous sea surface temperatures to investigate the role of the horizontal resolution (T42 versus T106) in determining the El Niño/Southern Oscillation (ENSO) response in the North Atlantic/European region. The higher resolution has been chosen in order to represent more realistically the transient eddy activity that is supposed to play a crucial role in the signal communication to regions remote from the tropical Pacific. In contrast to the T42 experiments, the T106 experiments reveal significant changes both in the mean of selected atmospheric variables (sea level pressure, temperature, precipitation) over Europe and in the transient and stationary wave activity. A cyclone tracking analysis reveals a southward shift of the North Atlantic low pressure systems in the winter season during El Niño events
On North Pacific Multidecadal Cllimate Variability
The multidecadal climate variability in the North Pacific region is investigated by using a 2000-yr-long integration with a coupled ocean–atmosphere general circulation model. It is shown that the multidecadal variability evolves largely independent of the variations in the tropical Pacific, so that this kind of multidecadal variability may be regarded as internal to the North Pacific. The coupled model results suggest that the multidecadal variability can be explained by the dynamical ocean response to stochastic wind stress forcing. Superimposed on the red background variability, a multidecadal mode with a period of about 40 yr is simulated by the coupled model. This mode can be understood through the concept of spatial resonance between the ocean and the atmosphere
A review of predictability studies of the Atlantic sector climate on decadal time-scales
This review paper discusses the physical basis and the potential for decadal climate predictability over the Atlantic and its adjacent land areas. Many observational and modeling studies describe pronounced decadal and multidecadal variability in the Atlantic Ocean. However, it still needs to be quantified to which extent the variations in the ocean drive variations in the atmosphere and over land. In particular, although a clear impact of the Tropics on the midlatitudes has been demonstrated, it is unclear if and how the extratropical atmosphere responds to midlatitudinal sea surface temperature anomalies.
Although the mechanisms behind the decadal to multidecadal variability in the Atlantic sector are still controversial, there is some consensus that some of the longer-term multidecadal variability is driven by variations in the thermohaline circulation. The variations in the North Atlantic thermohaline circulation appear to be predictable one to two decades ahead, as shown by a number of perfect model predictability experiments. The next few decades will be dominated by these multidecadal variations, although the effects of anthropogenic climate change are likely to introduce trends. Some impact of the variations of the thermohaline circulation on the atmosphere has been demonstrated in some studies so that useful decadal predictions with economic benefit may be possible
Estimating the Decadal Predictability of a Coupled AOGCM.
On seasonal time scales, ENSO prediction has become feasible in an operational framework in recent years. On decadal to multidecadal time scales, the variability of the oceanic circulation is assumed to provide a potential for climate prediction. To investigate the decadal predictability of the coupled atmosphere–ocean general circulation model (AOGCM) European Centre-Hamburg model version 5/Max Planck Institute Ocean Model (ECHAM5/MPI-OM), a 500-yr-long control integration and “perfect model” predictability experiments are analyzed. The results show that the sea surface temperatures (SSTs) of the North Atlantic, Nordic Seas, and Southern Ocean exhibit predictability on multidecadal time scales. Over the ocean, the predictability of surface air temperature (SAT) is very similar to that of SST. Over land, there is little evidence of decadal predictability of SAT except for some small maritime-influenced regions of Europe. The AOGCM produces predictable signals in lower-tropospheric temperature and precipitation over the North Atlantic, but not in sea level pressure
An ocean model's response to North Atlantic Oscillation like wind forcing
The response of the Atlantic Ocean to North Atlantic Oscillation (NAO)-like wind forcing was investigated using an ocean-only general circulation model coupled to an atmospheric boundary layer model. A series of idealized experiments was performed to investigate the interannual to multi-decadal frequency response of the ocean to a winter wind anomaly pattern. Overall, the strength of the SST response increased slightly with longer forcing periods. In the subpolar gyre, however, the model showed a broad response maximum in the decadal band (12-16 years)
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