163 research outputs found
Prevailing Surface Wind Direction during Air-Sea Heat Exchange
While the climatological-mean sensible and latent heat fluxes are remarkably well described using climatological-mean fields in the bulk flux formulas, this study shows that a significant fraction of the climatological-mean wind speed in the midlatitudes is associated with wind variations on synoptic time scales. Hence, the prevailing wind direction associated with the most intense air–sea heat exchange can differ from the mean wind direction. To pinpoint these striking differences between the climatological and synoptic viewpoint, this study presents a global climatology of the prevailing surface wind direction during air–sea heat exchanges calculated for instantaneous and time-averaged reanalysis data. The interpretation of the fluxes in the lower latitudes is basically unaffected by the different time averages, highlighting the time-mean nature of the circulation in the lower latitudes. In the midlatitudes, however, the prevailing wind direction features a significant equatorward component for subweekly time averages and reverts to pure westerlies for longer time averages. These findings pinpoint the necessity to consider subweekly time scales, in particular along the midlatitude SST fronts, to describe the air–sea heat exchange in a physically consistent way.publishedVersio
Oceanic forcing of the global warming slowdown in multi-model simulations
Abstract
Concurrent with the slowdown of global warming during 2002–2013, the wintertime
land surface air temperatures over Eurasia, North America, Africa,
Australia, South America, and Greenland experienced notable cooling trends.
The oceanic effects on the continental cooling trends are here investigated
using two sets of uncoupled experiments with six different climate models.
Daily and annually varying sea ice is prescribed for both sets of experiments,
while daily and annually varying SST is used in the first set (EXP1) and daily
and annually repeating climatological mean SST in the second set (EXP2). All
six models capture the slowdown of global-mean land surface air temperature
during 2002–2013 winters in EXP1 only. The slowdown concurs with a negative
phase of the Pacific Decadal Oscillation (PDO), indicating that PDO plays
an important role in modulating the global warming signal. Not all ensemble
members capture the cooling trends over the continents, suggesting additional
contribution from internal atmospheric variability.
KEYWORDS
continental cooling, global warming, multi-model simulations, Pacific Decadal Oscillationpublished versio
Factors affecting extreme rainfall events in the South Pacific
Extreme rainfall events in the South Pacific are widespread and affected by various factors on different time scales. We use daily rainfall data from 20 stations over the South Pacific to investigate the characteristics of extreme rainfall events from 1979 to 2018. For regional analysis, we group the stations into three clusters characterizing the western, the central, and the far eastern regions of the South Pacific Convergence Zone (SPCZ). Extreme rainfall events contribute to roughly 20% of the seasonal mean rainfall in all three clusters. Among all four factors considered, tropical cyclones (TCs) cause the highest increase in the probability (ΔpwesternSPCZ~286%, ΔpcentralSPCZ~84%, ΔpfareasternSPCZ~189%) of extreme rainfall events. The Madden-Julian Oscillation (MJO) is the second most important factor affecting the probability of extreme rainfall events, increasing it by 30–60% when the MJO is active over the western SPCZ in phases 5–6, over the central SPCZ in phases 6–7, and over the far eastern SPCZ in phases 8–1. The probability is reduced by the same order of magnitudes during the opposite dry phases of the MJO, i.e., phases 1–3 for the western and central SPCZ, and 3–6 for far the eastern SPCZ region. The probability of extreme rainfall events increases during La-Niña (El-Niño) conditions to the southwest (southeast) of the mean SPCZ by 27% (31%); however, the impact of the El-Niño and Southern Oscillation (ENSO) along the SPCZ is not apparent. Dynamical analysis shows that the favorable conditions for generating extreme rainfall events are associated with northwesterly moisture transport and its convergence. The impact of TCs, MJO, and ENSO on rainfall extreme events can be partly understood considering this dynamical analysis. Extratropical Rossby waves can trigger tropical disturbances, but their impact on extreme rainfall events is generally less important than of the TCs, MJO, and ENSO.publishedVersio
Impact of ocean and sea ice initialisation on seasonal prediction skill in the Arctic
There is a growing demand for skillful prediction systems in the Arctic. Using the Norwegian Climate Prediction Model (NorCPM) that combines the fully-coupled Norwegian Earth System Model and the Ensemble Kalman filter, we present a system that performs both, weakly-coupled data assimilation (wCDA) when assimilating ocean hydrogaphy (by updating the ocean alone) and strongly-coupled data assimilation (sCDA) when assimilating sea ice concentration (SIC) (by jointly updating the sea ice and ocean). We assess the seasonal prediction skill of this version of NorCPM, the first climate prediction system using sCDA, by performing retrospective predictions (hindcasts) for the period 1985 to 2010. To better understand origins of the prediction skill of Arctic sea ice, we compare this version with a version that solely performs wCDA of ocean hydrography. The reanalysis that assimilates just ocean data, exhibits a skillful hydrography in the upper Arctic ocean, and features an improved sea ice state, such as improved summer SIC in the Barents Sea, or reduced biases in sea ice thickness. Skillful prediction of SIE up to 10-12 lead months are only found during winter in regions of a relatively deep ocean mixed layer outside the Arctic basin. Additional DA of SIC data notably further corrects the initial sea ice state, confirming the applicability of the results of Kimmritz et al. (2018) in a historical setting. The resulting prediction skill of SIE is widely enhanced compared to predictions initialised through wCDA of only ocean data. Particularly high skill is found for July-initialised autumn SIE predictions.publishedVersio
DISC1 variants 37W and 607F disrupt its nuclear targeting and regulatory role in ATF4-mediated transcription
Disrupted-In-Schizophrenia 1 (DISC1), a strong genetic candidate for psychiatric illness, encodes a multicompartmentalized molecular scaffold that regulates interacting proteins with key roles in neurodevelopment and plasticity. Missense DISC1 variants are associated with the risk of mental illness and with brain abnormalities in healthy carriers, but the underlying mechanisms are unclear. We examined the effect of rare and common DISC1 amino acid substitutions on subcellular targeting. We report that both the rare putatively causal variant 37W and the common variant 607F independently disrupt DISC1 nuclear targeting in a dominant-negative fashion, predicting that DISC1 nuclear expression is impaired in 37W and 607F carriers. In the nucleus, DISC1 interacts with the transcription factor Activating Transcription Factor 4 (ATF4), which is involved in the regulation of cellular stress responses, emotional behaviour and memory consolidation. At basal cAMP levels, wild-type DISC1 inhibits the transcriptional activity of ATF4, an effect that is weakened by both 37W and 607F independently, most likely as a consequence of their defective nuclear targeting. The common variant 607F additionally reduces DISC1/ATF4 interaction, which likely contributes to its weakened inhibitory effect. We also demonstrate that DISC1 modulates transcriptional responses to endoplasmic reticulum stress, and that this modulatory effect is ablated by 37W and 607F. By showing that DISC1 amino acid substitutions associated with psychiatric illness affect its regulatory function in ATF4-mediated transcription, our study highlights a potential mechanism by which these variants may impact on transcriptional events mediating cognition, emotional reactivity and stress responses, all processes of direct relevance to psychiatric illness
Long-term prognosis of diabetic patients with acute myocardial infarction in the era of acute revascularization
Abstract Background The long-term prognosis of diabetic patients with acute myocardial infarction (AMI) treated by acute revascularization is uncertain, and the optimal pharmacotherapy for such cases has not been fully evaluated. Methods To elucidate the long-term prognosis and prognostic factors in diabetic patients with AMI, a prospective, cohort study involving 3021 consecutive AMI patients was conducted. All patients discharged alive from hospital were followed to monitor their prognosis every year. The primary endpoint of the study was all-cause mortality, and the secondary endpoint was the occurrence of major cardiovascular events. To elucidate the effect of various factors on the long-term prognosis of AMI patients with diabetes, the patients were divided into two groups matched by propensity scores and analyzed retrospectively. Results Diabetes was diagnosed in 1102 patients (36.5%). During the index hospitalization, coronary angioplasty and coronary thrombolysis were performed in 58.1% and 16.3% of patients, respectively. In-hospital mortality of diabetic patients with AMI was comparable to that of non-diabetic AMI patients (9.2% and 9.3%, respectively). In total, 2736 patients (90.6%) were discharged alive and followed for a median of 4.2 years (follow-up rate, 96.0%). The long-term survival rate was worse in the diabetic group than in the non-diabetic group, but not significantly different (hazard ratio, 1.20 [0.97-1.49], p = 0.09). On the other hand, AMI patients with diabetes showed a significantly higher incidence of cardiovascular events than the non-diabetic group (1.40 [1.20-1.64], p Conclusions Although diabetic patients with AMI have more frequent adverse events than non-diabetic patients with AMI, the present results suggest that acute revascularization and standard therapy with aspirin and RAS inhibitors may improve their prognosis.</p
高齢夜間頻尿患者における夜間尿産生に対する閉塞性睡眠時無呼吸症候群の影響
OBJECTIVE:
To investigate the impact of obstructive sleep apnea syndrome (OSAS) on night-time secretion of brain natriuretic peptide (BNP) and antidiuretic hormone (ADH) in older men with nocturia accompanied by nocturnal polyuria.
MATERIALS AND METHODS:
One hundred six men with nocturia aged ≥ 60 years underwent full-night polysomnography to determine whether they had OSAS. Blood count, standard chemistry panel, BNP, urinary ADH, urinary creatinine (u-Cre), and urinary osmolarity were measured at 6:00 AM, and a frequency volume chart was recorded on the same day that polysomnography was performed.
RESULTS:
We evaluated 83 patients after excluding 18 with mild OSAS and 5 with nocturnal polyuria index <0.35. Participants with OSAS had higher apnea-hypopnea index (P < .0001) than those without OSAS. Body mass index and systolic blood pressure were higher in OSAS patients than those in the control group. BNP was higher in the OSAS patients than in the control patients (48.6 ± 41.4 vs 30.7 ± 31.5; P = .0006). On urinalysis, OSAS patients showed higher urinary sodium and u-Cre secretion than controls (24.7 ± 11.3 vs 16.2 ± 5.1; P <.0001). Urine osmolarity was also higher in OSAS patients than in the control patients (616 ± 172 vs 516 ± 174; P = .0285). There was no significant difference in urinary ADH and u-Cre (6.7 ± 10.4 vs 6.8 ± 7.8; P = .3617) between the 2 groups.
CONCLUSION:
Our results indicated that older men with nocturnal polyuria and OSAS did not compensate their fluid imbalance presented with decreased secretion of ADH but increased BNP level.博士(医学)・乙第1349号・平成26年12月3日Copyright © 2014 Elsevier Inc. All rights reserved
Intensity-modulated radiation therapy dose verification using fluence and portal imaging device
Patient-specific quality assurance for intensity-modulated radiation therapy (IMRT) dose verification is essential. The aim of this study is to provide a new method based on the relative error distribution by comparing the fluence map from the treatment planning system (TPS) and the incident fluence deconvolved from the electronic portal imaging device (EPID) images. This method is validated for 10 head and neck IMRT cases. The fluence map of each beam was exported from the TPS and EPID images of the treatment beams were acquired. Measured EPID images were deconvolved to the incident fluence with proper corrections. The relative error distribution between the TPS fluence map and the incident fluence from the EPID was created. This was also created for a 2D diode array detector. The absolute point dose was measured with an ionization chamber, and the dose distribution was measured by a radiochromic film. In three cases, MLC leaf positions were intentionally changed to create the dose error as much as 5% against the planned dose and our fluence-based method was tested using gamma index. Absolute errors between the predicted dose of 2D diode detector and of our method and measurements were 1.26% ± 0.65% and 0.78% ± 0.81% respectively. The gamma passing rate (3% global / 3 mm) of the TPS was higher than that of the 2D diode detector (p< 0.02), and lower than that of the EPID (p < 0.04). The gamma passing rate (2% global / 2 mm) of the TPS was higher than that of the 2D diode detector, while the gamma passing rate of the TPS was lower than that of EPID (p < 0.02). For three modified plans, the predicted dose errors against the measured dose were 1.10%, 2.14%, and -0.87%. The predicted dose distributions from the EPID were well matched to the measurements. Our fluence-based method provides very accurate dosimetry for IMRT patients. The method is simple and can be adapted to any clinic for complex cases
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