342 research outputs found
Slow and Fast Transitions in the Rising Phase of Outbursts from NS-LMXB transients, AqlX-1 and 4U1608-52
We analyzed the initial rising behaviors of X-ray outbursts from two
transient low-mass X-ray binaries (LMXBs) containing a neutron-star (NS), Aql
X-1 and 4U 1608-52, which are continuously being monitored by MAXI/GSC in 2--20
keV, RXTE/ASM in 2--10 keV, and Swift/BAT in 15--50 keV. We found that the
observed ten outbursts are classified into two types by the patterns of the
relative intensity evolutions in the two energy bands below/above 15 keV. One
type behaves as the 15--50 keV intensity achieves the maximum during the
initial hard-state period and drops greatly at the hard-to-soft state
transition. On the other hand, the other type does as both the 2--15 keV and
the 15--50 keV intensities achieve the maximums after the transition. The
former have the longer initial hard-state ( 9 d) than the latter's
(\ltsim5 d). Therefore, we named them as slow-type (S-type) and fast-type
(F-type), respectively. These two types also show the differences in the
luminosity at the hard-to-soft state transition as well as in the average
luminosity before the outburst started, where the S-type are higher than the
F-type in the both. These results suggest that the X-ray radiation during the
pre-outburst period, which heats up the accretion disk and delays the disk
transition (i.e., from a geometrically thick disk to a thin one), would
determine whether the following outburst becomes S-type or F-type. The
luminosity when the hard-to-soft state transition occurs is higher than erg s in the S-type, which corresponds to 4% of the
Eddington luminosity for a 1.4 \Mo NS.Comment: 14 pages, 10 figures; Publications of the Astronomical Society of
Japan, 201
Avoided ferromagnetic quantum critical point in CeZn
Cubic CeZn shows a structural phase transition under pressure, and it
modifies the ground state from an antiferromagnetic (AFM) state to a
ferromagnetic (FM) state. To investigate how the FM state terminates at a
quantum phase transition, we measured the electrical resistivity under pressure
for a single crystal CeZn. The transition temperature into the FM state
decreases monotonously with increasing pressure, accompanied by the pronounced
Kondo effect, but a drastic change in the field response occurs before the
ordered phase terminates. This result suggests that the FM quantum critical
point is avoided by the appearance of an AFM-like state.Comment: 5 pages, 3 figure
Prevalence of Chronic Kidney Disease and Variation of Its Risk Factors by the Regions in Okayama Prefecture
Objective: The prevention of chronic kidney disease (CKD) progression is an important issue from health and financial perspectives. We conducted a single-year cross-sectional study to clarify the prevalence of CKD and its risk factors along with variations in these factors among five medical regions in Okayama Prefecture, Japan. Methods and Results: Data concerning the renal function and proteinuria as well as other CKD risk factors were obtained from the database of the Japanese National Health Insurance. The proportion of CKD patients at an increased risk of progression to end-stage renal disease (ESRD), classified as orange and red on the CKD heatmap, ranged from 6-9% and did not vary significantly by the regions. However, the causes of the increased severity differed between regions where renal dysfunction was predominant and regions where there were many patients with proteinuria. CKD risk factors, such as diabetes mellitus, hypertension, hyper low-density lipoprotein-cholesterolemia, obesity, smoking and lack of exercise, also differed among these regions, suggesting that different regions need tailored interventions that suit the characteristics of the region, such as an increased health checkup ratio, dietary guidance and promotion of exercise opportunities. Conclusions: Approximately 6-9% of people are at an increased risk of developing ESRD (orange or red on a CKD heatmap) among the population with National Health Insurance in Okayama Prefecture. The underlying health problems that cause CKD may differ among the regions. Thus, it is necessary to consider intervention methods for preventing CKD progression that are tailored to each region's health problems
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