Cross-user subsidy in residential broadband service

Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 38-40).The rapid growth of Internet traffic has made Internet Service Providers (ISP) struggle to upgrade network capacity and to maintain service quality. The increase in the broadband usage impacts the cost of an ISP through usage-associated costs such as incremental usage cost, cost for expanding the network capacity, and cost from subscriber churns. This paper attempts to understand the relation between broadband usage and incremental usage cost. This thesis addresses issues on connecting the broadband usage to the usage-sensitive costs. How much do the light users spend to support the heavy users by paying the equal usage fee? To answer the question, it should be investigated how much incremental cost is generated by using networks and how the traffic load is distributed over the users. The research is based on the commercial broadband usage data sample and the published financial statements from a major broadband service provider in Korea, Korea Telecom. Analyzing the broadband usage reveals to us what the usage distribution looks like and how the distribution evolves over time.(cont.) By examining the published financial data, the cost directly associated with the broadband usage is estimated. The usage distribution and the estimated cost is incorporated to find an answer to how much burden the light users are carrying to subsidize the heavy users on the network under the current flat usage fee system.by Jungwon Min.S.M

Resting heart rate variability is associated with neural adaptation when repeatedly exposed to emotional stimuli.

Higher heart rate variability (HRV) at rest is associated with better emotion regulation ability. While the neurovisceral integration model explains this by postulating that HRV can index how the brain adaptively modulates responses to emotional stimuli, neuroimaging studies directly supporting this idea are scarce. We examined the neural correlates of regulating negative and positive emotion in relation to resting HRV based on the neuroimaging and heart rate data of one hundred young adults. The results showed that those with higher HRV better recruit the medial prefrontal cortex while intensifying positive compared to negative emotion. We also examined how individual differences in resting HRV are associated with adjusting brain activity to repeated emotional stimuli. During repeated viewing of emotional images, subjects with higher resting HRV better reduced activity in the medial prefrontal cortex, posterior cingulate gyrus, and angular gyrus, most of which overlapped with the default mode network. This HRV-DMN association was observed during passively viewing emotional images rather than during actively regulating emotion. While the regulating trials can better detect task-induced changes, the viewing trials might approximate resting state, better revealing individual differences. These findings suggest two possibilities: people with higher resting HRV might have a tendency to spontaneously engage with emotion regulation or possess a trait helping emotional arousal fade away

Effect of the Adapted NASA Mission X International Child Fitness Program on Young Children and their Parents in South Korea

Obesity has become a global epidemic. Childhood obesity is global public health concern including in South Korea where 16.2% of boys and 9.9% of girls are overweight or obese in 2011. Effective and sustainable intervention programs are needed for prevention of childhood obesity. Obesity prevention programs for young children may have a greater intervention effect than in older children. The NASA Mission X: Train Like an Astronaut (MX) program was developed to promote children's exercise and healthy eating by tapping into their excitement for training like an astronaut. This study aimed to examine the feasibility and effectiveness of the adapted NASA MX intervention in promoting PA in young children and in improving parents' related perspectives

Effects of a randomised trial of 5-week heart rate variability biofeedback intervention on mind wandering and associated brain function

Previous research suggests that excessive negative self-related thought during mind wandering involves the default mode network (DMN) core subsystem and the orbitofrontal cortex (OFC). Heart rate variability (HRV) biofeedback, which involves slow paced breathing to increase HRV, is known to promote emotional well-being. However, it remains unclear whether it has positive effects on mind wandering and associated brain function. We conducted a study where young adults were randomly assigned to one of two 5-week interventions involving daily biofeedback that either increased heart rate oscillations via slow paced breathing (Osc+ condition) or had little effect on heart rate oscillations (active control or Osc- condition). The two intervention conditions did not differentially affect mind wandering and DMN core-OFC functional connectivity. However, the magnitude of participants’ heart rate oscillations during daily biofeedback practice was associated with pre-to-post decreases in mind wandering and in DMN core-OFC functional connectivity. Furthermore, the reduction in the DMN core-OFC connectivity was associated with a decrease in mind wandering. Our results suggested that daily sessions involving high amplitude heart rate oscillations may help reduce negative mind wandering and associated brain function.</p

Higher locus coeruleus MRI contrast is associated with lower parasympathetic influence over heart rate variability

The locus coeruleus (LC) is a key node of the sympathetic nervous system and suppresses parasympathetic activity that would otherwise increase heart rate variability. In the current study, we examined whether LC-MRI contrast reflecting neuromelanin accumulation in the LC was associated with high-frequency heart rate variability (HF-HRV), a measure reflecting parasympathetic influences on the heart. Recent evidence indicates that neuromelanin, a byproduct of catecholamine metabolism, accumulates in the LC through young and mid adulthood, suggesting that LC-MRI contrast may be a useful biomarker of individual differences in habitual LC activation. We found that, across younger and older adults, greater LC-MRI contrast was negatively associated with HF-HRV during fear conditioning and spatial detection tasks. This correlation was not accounted for by individual differences in age or anxiety. These findings indicate that individual differences in LC structure relate to key cardiovascular parameters

Indexed oxygen delivery during pediatric cardiopulmonary bypass is a modifiable risk factor for postoperative acute kidney injury

Background: Acute kidney injury after pediatric cardiac surgery is a common complication with few established modifiable risk factors. We sought to characterize whether indexed oxygen delivery during cardiopulmonary bypass was associated with postoperative acute kidney injury in a large pediatric cohort. Methods: This was a retrospective analysis of patients under 1 year old undergoing cardiac surgery with cardiopulmonary bypass between January 1, 2013, and January 1, 2020. Receiver operating characteristic curves across values ranging from 260 to 400 mL/min/m2 were used to identify the indexed oxygen delivery most significantly associated with acute kidney injury risk. Results: We included 980 patients with acute kidney injury occurring in 212 (21.2%). After adjusting for covariates associated with acute kidney injury, an indexed oxygen delivery threshold of 340 mL/min/m2 predicted acute kidney injury in STAT 4 and 5 neonates (area under the curve = 0.66, 95% CI = 0.60 – 0.72, sensitivity = 56.1%, specificity = 69.4%). An indexed oxygen delivery threshold of 400 mL/min/m2 predicted acute kidney injury in STAT 1-3 infants (area under the curve = 0.65, 95% CI = 0.58 – 0.72, sensitivity = 52.6%, specificity = 74.6%). Conclusion: Indexed oxygen delivery during cardiopulmonary bypass is a modifiable variable independently associated with postoperative acute kidney injury in specific pediatric populations. Strategies aimed at maintaining oxygen delivery greater than 340 mL/min/m2 in complex neonates and greater than 400 mL/min/m2 in infants may reduce the occurrence of postoperative acute kidney injury in the pediatric population

Hemolytic Disease of the Newborn Associated with Anti-Jr(a) Alloimmunization in a Twin Pregnancy: The First Case Report in Korea

Jr(a) is a high-frequency antigen found in all ethnic groups. However, the clinical significance of the anti-Jr(a) antibody has remained controversial. Most studies have reported mild hemolytic disease of the newborn and fetus (HDNF) in Jr(a)-positive patients. Recently, fatal cases of HDNF have also been reported. We report the first case of HDNF caused by anti-Jr(a) alloimmunization in twins in Korea. A 33-yr-old nulliparous woman with no history of transfusion or amniocentesis was admitted at the 32nd week of gestation because of vaginal bleeding caused by placenta previa. Anti-Jr(a) antibodies were detected in a routine laboratory examination. An emergency cesarean section was performed at the 34th week of gestation, and 2 premature infant twins were delivered. Laboratory examination showed positive direct antiglobulin test and Jr(a+) phenotype in the red blood cells and the presence of anti-Jr(a) antibodies in the serum in both neonates. The infants underwent phototherapy for neonatal jaundice; this was followed by conservative management. They showed no further complications and were discharged on the 19th postpartum day. Preparative management to ensure the availability of Jr(a-) blood, via autologous donation, and close fetal monitoring must be performed even in cases of first pregnancy in Jr(a-) women. (Korean J Lab Med 2010;30:511-5)Arriaga F, 2009, TRANSFUSION, V49, P813, DOI 10.1111/j.1537-2995.2009.02118.xPeyrard T, 2008, TRANSFUSION, V48, P1906, DOI 10.1111/j.1537-2995.2008.01787.xROBACK JD, 2008, TECHNICAL MANUAL, P411CHUNG HJ, 2007, KOREAN J BLOOD TRANS, V18, P111Ishihara Y, 2006, FETAL DIAGN THER, V21, P269, DOI 10.1159/000091354Daniels GL, 2004, VOX SANG, V87, P304Kwon MY, 2004, TRANSFUSION, V44, P197Bellver-Pradas J, 2001, AM J OBSTET GYNECOL, V184, P75STROUP M, 1970, P 23 ANN M AM ASS BL, P86KIM DW, 1995, ELS APPL ELECT MAT, V6, P185MIYAZAKI T, 1994, VOX SANG, V66, P51OGASAWARA K, 1990, ACTA HAEMATOL JAPON, V53, P1131GARRATTY G, 1990, TRANSFUS MED REV, V4, P297NANCE SJ, 1987, TRANSFUSION, V27, P449BACON J, 1986, TRANSFUSION, V26, P543LEVENE C, 1986, TRANSFUSION, V26, P119TAKABAYASHI T, 1985, TOHOKU J EXP MED, V145, P97TOY P, 1981, VOX SANG, V41, P40ORRICK LR, 1980, AM J OBSTET GYNECOL, V137, P135NAKAJIMA H, 1978, VOX SANG, V35, P265VEDO M, 1978, TRANSFUSION, V18, P569TRITCHLER JE, 1977, TRANSFUSION, V17, P177KENDALL AG, 1976, TRANSFUSION, V16, P646

Studies of aggregated nanoparticles steering during magnetic-guided drug delivery in the blood vessels

Magnetic-guided targeted drug delivery (TDD) systems can enhance the treatment of diverse diseases. Despite the potential and promising results of nanoparticles, aggregation prevents precise particle guidance in the vasculature. In this study, we developed a simulation platform to investigate aggregation during steering of nanoparticles using a magnetic field function. The magnetic field function (MFF) comprises a positive and negative pulsed magnetic field generated by electromagnetic coils, which prevents adherence of particles to the vessel wall during magnetic guidance. A commonly used Y-shaped vessel was simulated and the performance of the MFF analyzed; the experimental data were in agreement with the simulation results. Moreover, the effects of various parameters on magnetic guidance were evaluated and the most influential identified. The simulation results presented herein will facilitate more precise guidance of nanoparticles in vivo