5,176 research outputs found
Extracellular vesicles from adipose tissue - a potential role in obesity and type 2 diabetes?
Adipose tissue plays a key role in the development of insulin resistance and its pathological sequelae such as type 2 diabetes and non-alcoholic fatty liver disease. Dysfunction in the adipose tissue response to storing excess fatty acids as triglyceride can lead to adipose tissue inflammation and spillover of fatty acids from this tissue and accumulation of fatty acids as lipid droplets in ectopic sites such as liver and muscle. Extracellular vesicles (EV) are released from adipocytes and have been proposed to be involved in adipocyte/macrophage crosstalk and to affect insulin signalling and TGFĪ² expression in liver cells leading to metabolic disease. Furthermore EV produced by adipose tissue-derived mesenchymal stem cells (ADSC) can promote angiogenesis and cancer cell migration and have neuroprotective and neuroregenerative properties. ADSC EV have therapeutic potential in vascular and neurodegenerative disease and may also be used to target specific functional miRNAs to cells. Obesity is associated with an increase in adipose-derived EV which may be related to the metabolic complications of obesity. This review aims to discuss EV produced by adipose tissue and their potential impact on metabolic diseases associated with obesity
What Affects Prospection? ā An Examination Of The Factors That Affect Future Time Perception, Sequence Preference For Future Experience, Or Future Temporal Orientation
The present research examines the factors that affect how people think about the future. Chapter 1 examines how choice affects future time perception. Two experiments manipulated the presence of choice regarding future experiences, and asked participants to indicate their subjective temporal distance to the future experiences. Results showed that the future experiences felt closer when people had a choice about them compared to when they did not have such a choice. Chapter 2 examines how valence and culture affect the sequence preference for future experiences. The results from two studies showed that people were more likely to prefer an ascending sequence for negative experiences than positive experiences, and that people were more likely to prefer a descending sequence for positive experiences than negative experiences. They also showed that Americans were more likely to prefer an ascending sequence than Indians and that Indians were more likely to prefer a descending sequence than Americans. Chapter 3 examines how culture affects temporal orientation. Building on prior research that has compared the cultural differences on past, present, and future orientation, I hypothesize that East Asians focus on the past and future more than North Americans, and North Americans focus on the present more than East Asians. It is suggested that in addition to a cultural difference in the focus on the three temporal domains, when moving from any past or future time point toward the present, North Americansā focus on the temporal domain grows more than East Asiansā focus. I present evidence in three categories. Specially, I compare East Asiansā and North Americansā focus on a temporal domain, their mental representation of a temporal domain and their subjective temporal distance to a temporal domain
Higher rank tropicalization
A higher rank valuation is a function that maps a ļ¬eld to the union of an ordered abelian group and inļ¬nity. There are studies that have shown that Kapranovās theorem still holds when the valuation is of rank n > 1 and the rank n tropicalization of a d-dimensional variety is a polyhedral complex of dimension nd, etc. This thesis aims to focus on higher rank valuation, we present a method about how to reduce a higher rank valuation to a sequence of classic valuations. With this method, we can describe the structure of the tropicalization over a higher rank valuation in terms of rank 1 tropicalisations, which will help us to reprove Kapranovās theorem in an alternative way
Bright broad-band afterglows of gravitational wave bursts from mergers of binary neutron stars
If double neutron star mergers leave behind a massive magnetar rather than a
black hole, a bright early afterglow can follow the gravitational wave burst
(GWB) even if there is no short gamma-ray burst (SGRB) - GWB association or
there is an association but the SGRB does not beam towards earth. Besides
directly dissipating the proto-magnetar wind as suggested by Zhang, we here
suggest that the magnetar wind could push the ejecta launched during the merger
process, and under certain conditions, would reach a relativistic speed. Such a
magnetar-powered ejecta, when interacting with the ambient medium, would
develop a bright broad-band afterglow due to synchrotron radiation. We study
this physical scenario in detail, and present the predicted X-ray, optical and
radio light curves for a range of magnetar and ejecta parameters. We show that
the X-ray and optical lightcurves usually peak around the magnetar spindown
time scale (10^3-10^5s), reaching brightness readily detectable by wide-field
X-ray and optical telescopes, and remain detectable for an extended period. The
radio afterglow peaks later, but is much brighter than the case without a
magnetar energy injection. Therefore, such bright broad-band afterglows, if
detected and combined with GWBs in the future, would be a probe of massive
millisecond magnetars and stiff equation-of-state for nuclear matter.Comment: ApJ, in pres
SIMULTANEOUS MITIGATION OF SUBSYNCHRONOUS RESONANCE AND SUBSYNCHRONOUS INTERACTION USING FULL-SCALE FREQUENCY CONVERTER- AND DOUBLY-FED INDUCTION GENERATOR-BASED WIND FARMS
Subsynchronous Resonance (SSR) is one of the major obstacles for the wide spread of high degrees (60% and higher) of series capacitor compensation. Recently, a new obstacle, namely Subsynchronous Interaction (SSI) has been added to the list after the Zorillo Gulf wind farm incident in Texas in October 2009. SSI is due to the interaction between large Doubly-Fed Induction Generator (DFIG)-based wind farms and series capacitor compensated transmission systems.
In integrated power systems incorporating series capacitor compensated transmission lines and high penetration of wind energy conversion systems, especially DFIG-based wind farms, SSR and SSI could occur concurrently as a result of some system contingences. Therefore, mitigating SSR and SSI is an important area of research and development targeting at developing practical and effective countermeasures.
This thesis reports the results of digital time-domain simulation studies that are carried out to investigate the potential use of Full-Scale Frequency Converter (FFC) and DFIG-based wind farms for simultaneous mitigation of SSR and SSI. This is achieved through introducing supplemental control signals in the reactive power control loops of the grid side converters of the DFIG and/or the FFC wind turbines. In this context, two supplemental controls designated as Supplemental Controls 1 and 2 are examined. Supplemental Control 1 introduces a signal in the grid side converter of the FFC wind turbines to damp both SSR and SSI oscillations. On the other hand, Supplemental Control 2 introduces a signal in the grid side converter of the FFC wind turbines for damping SSR oscillations and another signal in the grid side converters of the DFIG wind turbines for damping SSI oscillations.
Time-domain simulations are conducted on a benchmark model using the ElectroMagnetic Transients program (EMTP-RV). The results of the investigations have demonstrated that the presented two supplemental controls are very effective in mitigating the SSR and SSI phenomena at different system contingencies and operating conditions
A double neutron star merger origin for the cosmological relativistic fading source PTF11agg?
The Palomar Transient Factory (PTF) team recently reported the discovery of a
rapidly fading optical transient source, PTF11agg. A long-lived scintillating
radio counterpart was identified, but the search for a high energy counterpart
showed negative results. The PTF team speculated that PTF11agg may represent a
new class of relativistic outbursts. Here we suggest that a neutron star
(NS)-NS merger system with a supra-massive magnetar central engine could be a
possible source to power such a transient, if our line of sight is not on the
jet axis direction of the system. These systems are also top candidates for
gravitational wave sources to be detected in the advanced LIGO/Virgo era. We
find that the PTF11agg data could be explained well with such a model,
suggesting that at least some gravitational wave bursts due to NS-NS mergers
may be associated with such a bright electromagnetic counterpart without a
\gamma-ray trigger.Comment: Accepted for publication in ApJ Letter
Understanding the Values of Live Game Streaming: a Value-Focused Thinking Approach
Today, along with the development of information communication technology, live streaming is getting more and more popular in China. It has established an integrated industrial chain. There are a large number of users watching different live streams (e.g., games. sports, live shows) through personal computers and mobile devices. In this paper, we aim to investigate the values of live game streaming using the Value-Focused Thinking (VFT) approach. We analyze the values of live game streaming from the perspectives of both streamers and spectators. The identified values are represented in the form of a means-ends objective network. The means-ends objective network derived from this research can serve as a conceptual foundation for future studies and provide useful guidelines for practitioners to better operate live game streaming applications
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