Extreme space weather conditions pose significant problems for standard space weather models, which are available for some limited realistic parameter ranges. As a good example, anomalous spikes of ...cosmic ray induced 10Be have been found during the Maunder Minimum (AD1645–1715) at the qA negative solar minima, which cannot be quantitatively explained by standard drift theories of cosmic ray transport alone. Such an extreme amplification of solar cycle modulation of cosmic rays is presumably related to the altered condition of heliospheric environment at the prolonged sunspot disappearance, providing a clue for comprehensive understandings of long‐term changes in heliospheric environment, solar cycle modulation of cosmic rays, and the maximal range of incident cosmic ray flux that is very important for our practical space activities. Model sophistication to achieve precise forecast of such extreme condition of the heliosphere and the incoming cosmic ray flux is also of urgent need as the Sun is currently showing a tendency toward lower activity. Here we show that the cosmic ray spikes found at the Maunder Minimum may be explained by the contribution from the cross‐sector transport mechanism working in the heliosheath where cosmic ray particles effectively drift across stacked magnetic sectors due to the larger cyclotron radius than the distance between the sectors. Based on the new interpretation of the 10Be record, we clarify potentially important problems for space weather modelers to help with more realistic modeling of the heliosphere during periods of extremely weak solar activity, such as the Maunder Minimum.
Key Points
Anomalous spikes of 10Be are found during the Maunder Minimum
The spikes cannot be explained by drift theories of cosmic ray transport alone
The spikes are explained by cross‐sector mechanism working in the heliosheath
Saury oil contains considerable amounts of n-3 polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) with long aliphatic tails (>18C atoms). Ingestion of saury oil reduces the ...risk of developing metabolic syndrome concomitant with increases in n-3 PUFA and long-chain MUFA in plasma and organs of mice. We therefore evaluated changes in postprandial plasma fatty acid levels and plasma parameters in healthy human subjects after ingestion of a single meal of saury.
Five healthy human adults ingested 150 g of grilled saury. Blood was collected before the meal and at 2, 6, and 24 hr after the meal, and plasma was prepared. Plasma levels of eicosapentaenoic acid, docosahexaenoic acid, and long-chain MUFA (C20:1 and C22:1 isomers combined) increased significantly throughout the postprandial period compared with the pre-meal baseline. Postprandial plasma insulin concentration increased notably, and plasma levels of glucose and free fatty acids decreased significantly and subsequently returned to the pre-meal levels.
Our study suggests that a single saury meal may alter the postprandial plasma levels of n-3 PUFA and long-chain MUFA in healthy human subjects.
The objective of present study was to examine the effect of long-chain monounsaturated fatty acids (LC-MUFAs) with chain lengths longer than 18 (i.e., C20:1 and C22:1 isomers combined) on ...obesity-related metabolic dysfunction and its molecular mechanisms. Type-2 diabetic KK-Ay mice (n = 20) were randomly assigned to the 7% soybean oil-diet group (control group) and 4% LC-MUFA concentrate-supplemented-diet group (LC-MUFA group). At 8 weeks on the diet, the results showed that plasma, liver and adipose tissue levels of C20:1 and C22:1 isomers increased significantly with LC-MUFA treatment. Supplementation with LC-MUFAs markedly reduced white fat pad weight as well as adipocyte size in the mice. The levels of plasma free fatty acids, insulin, and leptin concentration in the obese diabetic mice of the LC-MUFA group were also decreased as compared with the mice in the soybean oil-diet control group. Dietary LC-MUFAs significantly increased the mRNA expression of peroxisome proliferator-activated receptor gamma (Pparg), lipoprotein lipase (Lpl), fatty acid transport protein (Fatp), fatty acid translocase/CD36 (Cd36), as well as mRNA expression of genes involved in lipid oxidation such as carnitine palmitoyltransferase-1A (Cpt1a) and citrate synthase (Cs), and decreased the mRNA expression of inflammatory marker serum amyloid A 3 (Saa3) in the adipose tissues of diabetic mice. The results suggest that LC-MUFAs may ameliorate obesity-related metabolic dysfunction partly through increased expression of Pparg as well as its target genes, and decreased inflammatory marker expression in white adipose tissue.
Studies have demonstrated the beneficial effect of palmitoleic acid (C16:1 n-7) on reducing muscle insulin resistance and preventing beta-cell apoptosis. However, the effect of palmitoleic acid on ...diabetes remains to be elucidated. The aim of this study was to examine the antidiabetic effect of palmitoleic acid in KK-Ay mice, a spontaneous model for studies of obese type 2 diabetes with low insulin sensitivity.
KK-Ay mice were orally administered vehicle, 300 mg/kg of palmitoleic acid, or 300 mg/kg of palmitic acid (C16:0) on a daily basis for 4 weeks.
Palmitoleic acid reduced body weight increase, ameliorated the development of hyperglycemia and hypertriglyceridemia, and improved insulin sensitivity. In addition, hepatic characteristics were significantly affected, as weight of the liver and hepatic triglyceride levels were lower in the palmitoleic acid group when compared to the control (vehicle and palmitic acid groups). Oil red O staining clearly indicated reduced hepatic lipid accumulation in response to palmitoleic acid. Furthermore, palmitoleic acid down-regulated mRNA expressions of proinflammatory adipocytokine genes (TNFα and resistin) in white adipose tissue and lipogenic genes (SREBP-1, FAS, and SCD-1) in liver.
These results suggest that palmitoleic acid improves hyperglycemia and hypertriglyceridemia by increasing insulin sensitivity, in part owing to suppressing proinflammatory gene expressions and improving hepatic lipid metabolism in diabetic mice.
Famciclovir is a guanine analog antiviral drug used commonly for herpes zoster. Efficacy of famciclovir treatment has been reported to be comparable to valacyclovir treatment. Both of these ...medications reduce the time to complete cessation of zoster‐associated pain including post‐herpetic neuralgia, as compared to acyclovir. We conducted a multicenter, randomized, open clinical trial in order to evaluate the extent of pain relief afforded by these two antiviral drugs during the acute disease phase of herpes zoster. The study group comprised 86 immunocompetent adult patients suffering from herpes zoster, who were treated with either famciclovir or valacyclovir for 7 days. Of these, 55 patients enrolled in this study within 72 h of the onset of the rash and 31 patients after 72 h of the onset. There was a significant reduction in acute herpes zoster pain with famciclovir on day 7 and at 2–3 weeks in both of these patient groups, while with valacyclovir, there was not significant reduction in pain on day 7. Of patients aged 50 years or older, there was a significantly earlier reduction in pain with famciclovir than with valacyclovir. In addition, a significant reduction in the number of patients with pain was observed as early as days 3–4 with famciclovir treatment as compared with valacyclovir treatment. We conclude that famciclovir was superior to valacyclovir in the relief of acute pain of herpes zoster. Accordingly, famciclovir is recommended for herpes zoster patients with moderate symptoms and a visual analog scale score of under 50 mm.
Abstract The 10 Be record in laminated travertines is a potential proxy for reconstructing past solar activity down to the annual scale; however, correcting for the potential influence of climatic or ...environmental variations remains challenging. Here, we present an annually resolved 10 Be record using travertines from Baishuitai, China, covering the period from 1510 to 1701 CE, along with environmental proxies, to evaluate climatic influences and implement corrections to accurately reconstruct solar activity. We demonstrate that the 10 Be deposition in travertines exhibits two environmental impacts: the transport efficiency of atmospheric 10 Be into travertine and the additional 10 Be inflow from overland flow associated with rainfall. We show that these impacts can be corrected based on iron and potassium contents. The resulting corrected record agrees with ice‐core and tree‐ring records, demonstrating the feasibility of using such carbonate sediment 10 Be records to reconstruct past solar activity.
Plain Language Summary The travertine 10 Be record has great potential as a proxy for high‐resolution reconstruction of past solar activity; however, the methodology for correcting the potential influence of climatic or environmental variations has not been fully established. This study presents a new high‐precision annual 10 Be record using travertines from Baishuitai, China, covering the period 1510–1701 CE, together with records of environmental proxies, allowing us to evaluate the climatic influences and establish a methodology for correcting them to facilitate accurate solar activity reconstruction. We find that there are two environmental impacts on the deposition of 10 Be in travertine: one is the transport efficiency of atmospheric 10 Be into travertine, and the other is the additional 10 Be inflow from the runoff following rainfall events, and we use iron (Fe) and potassium (K) contents to correct these impacts. The corrected travertine 10 Be record exhibits good agreement with ice‐core 10 Be and tree‐ring 14 C records, supporting that the 10 Be record in Baishuitai travertine reliably reflects the atmospheric radionuclide production rate as regulated by solar activity. This result demonstrates the feasibility of using such carbonate sediment 10 Be records to reconstruct annual solar activity and suggests the possibility of extending the annual records further back in time than previously obtained.
Key Points A high‐precision annual record of travertine 10 Be from 1510 to 1701 CE was obtained to assess its potential as a proxy for solar activity Climatological and environmental impacts on 10 Be deposition were found to be correctable based on the content of trace elements The travertine 10 Be record corrected for climatological impacts reasonably preserves the decadal and centennial‐scale solar cycles
Paleoclimate studies have revealed that variations of Earth's climate may be under the control of solar activity, heliospheric environment, and the surrounding condition of our galaxy. One ...possibility is that galactic cosmic rays are playing important role in climate change by promoting chemical reactions in the atmosphere to produce cloud condensation nuclei and change the albedo of the Earth. We suggest that habitability of extra-solar planets may be also influenced by surrounding space environment and the condition of stellarsphere.
This paper presents the results of our measurements of radiocarbon content in Japanese cedar trees for 1557–1629
AD, the interval of two grand solar minima called the Spoerer and the Maunder minima. ...We had measured the radiocarbon content around the Spoerer and the Maunder minima, aiming to clarify the characteristics of the 11-year solar cycle during prolonged sunspot minima. The time series of radiocarbon content obtained from Japanese cedar is now available 1413
AD through 1745
AD. Frequency analyses of the radiocarbon data for the Spoerer and the Maunder minima show that the Sun continues periodic variations even during periods of long-lasting sunspot absence, and that the actual length of the “11-year” solar cycle could be changed in association with long-term variations of the solar activity level with centennial time scale. In this paper, we analyze the variation of radiocarbon content during the interval between the two grand solar minima and compare with that during the Spoerer and the Maunder minima.
A three-dimensional time-dependent heliospheric model is developed with the adaptive mesh refinement (AMR) technique. The AMR code, SFUMATO, is adopted, which has been originally developed for ...star-formation problems. The solar wind model is based on the space weather forecast system, SUSANOO, and it is imposed on the inner boundary at r = 25 R⊙. The solar wind model is derived from magnetogram synoptic maps, which are observed daily. Using the potential field source surface models, the WS formula, and a few empirical laws, the MHD parameters at the inner boundary are reproduced. The heliospheric model here extends up to 14 au, and the AMR grid resolves the heliospheric current sheets and co-rotating interaction regions with refined resolutions. The AMR grid brings considerable improvement in the fine features in the outer region of r ≳ 2 au compared to the concentric nested grid, of which resolution has the relationship Δx ∝ r, similar to spherical coordinates. The refinement criteria are based mainly on the distance from the Sun, the anti-parallel toroidal magnetic fields, and the density of the solar wind.
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