1,502 research outputs found
One-loop effective potential in M4 x T2 with and without 't Hooft flux
We review the basic notions of compactification in the presence of a
background flux. In extra-dimentional models with more than five dimensions,
Scherk and Schwarz boundary conditions have to satisfy 't Hooft consistency
conditions. Different vacuum configurations can be obtained, depending whether
trivial or non-trivial 't Hooft flux is considered. The presence of the
"magnetic" background flux provide, in addition, a mechanism for producing
four-dimensional chiral fermions. Particularizing to the six-dimensional case,
we calculate the one-loop effective potential for a U(N) gauge theory on M4 x
T2. We firstly review the well known results of the trivial 't Hooft flux case,
where one-loop contributions produce the usual Hosotani dynamical symmetry
breaking. Finally we applied our result for describing, for the first time, the
one-loop contributions in the non-trivial 't Hooft flux case
Sirtuins 1–7 expression in human adipose-derived stem cells from subcutaneous and visceral fat depots: influence of obesity and hypoxia
The sirtuin family comprises seven NAD+-dependent deacetylases which control the overall health of organisms through the regulation of pleiotropic metabolic pathways. Sirtuins are important modulators of adipose tissue metabolism and their expression is higher in lean than obese subjects. At present, the role of sirtuins in adipose-derived stem cells has not been investigated yet. Therefore, in this study, we evaluated the expression of the complete panel of sirtuins in adipose-derived stem cells isolated from both subcutaneous and visceral fat of non-obese and obese subjects. We aimed at investigating the influence of obesity on sirtuins' levels, their role in obesity-associated inflammation, and the relationship with the peroxisome proliferator-activated receptor delta, which also plays functions in adipose tissue metabolism. The mRNA levels in the four types of adipose-derived stem cells were evaluated by quantitative polymerase chain reaction, in untreated cells and also after 8 h of hypoxia exposure. Correlations among sirtuins' expression and clinical and molecular parameters were also analyzed. We found that sirtuin1-6 exhibited significant higher mRNA expression in visceral adipose-derived stem cells compared to subcutaneous adipose-derived stem cells of non-obese subjects. Sirtuin1-6 levels were markedly reduced in visceral adipose-derived stem cells of obese patients. Sirtuins' expression in visceral adipose-derived stem cells correlated negatively with body mass index and C-reactive protein and positively with peroxisome proliferator-activated receptor delta. Finally, only in the visceral adipose-derived stem cells of obese patients hypoxia-induced mRNA expression of all of the sirtuins. Our results highlight that sirtuins' levels in adipose-derived stem cells are consistent with protective effects against visceral obesity and inflammation, and suggest a transcriptional mechanism through which acute hypoxia up-regulates sirtuins in the visceral adipose-derived stem cells of obese patients
The Effect of Computer Use on Job Quality: Evidence from Europe
This paper studies changes in computer use and job quality in the EU-15 between 1995 and 2015. We document that while the proportion of workers using computers has increased from 40% to more than 60% over twenty years, there remain significant differences between countries even within the same occupations. Several countries have seen a significant increase in computer use even in low-skilled occupations generally assumed to be less affected by technology. Overall, the great increase in computer use between 1995 and 2015 has coincided with a period of modest deterioration of job quality in the EU-15 as whole, as discretion declined for most occupational and educational groups while intensity increased slightly for most of them. Our OLS results that exploit variation within country-occupation cells point to a sizeable positive effect of computer use on discretion, but to small or no effect on intensity at work. Our instrumental variable estimates point to an even more benign effect of computer use on job quality. Hence, the results suggest that
the (moderate) deterioration in the quality of work observed in the EU-15 between 1995 and 2015 has occurred despite the spread of computers, rather than because of them
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A role for independent peer review: reflections on the gateway review process
Healthcare organisations face constant pressure to change in order to pursue quality and performance improvements. As a result, professionals are often said to be experiencing change fatigue. This can be problematic for policy implementation initiatives. This paper reflects on an informal Gateway Review of Leicester, Leicestershire and Rutland's Integrated Point of Access Programme to make the case for independent peer review of healthcare management change programmes in order to work towards reducing change fatigue and its impacts. Peer review has been identified as an effective but underused process across health and social care provision and management. With this in mind, the Gateway Review outlined here is used to exemplify some of the practical benefits and challenges of external peer review. Based on this experience, a number of learning points and recommendations are outlined for those undertaking or thinking about undertaking peer review in healthcare management
Could the periodontal therapy improve the cardiologic patient health? A narrative review
Background: Cardiovascular diseases (CVD) is the major cause of mortality globally, with increasing evidence suggesting a link between periodontitis, and CVD. This study aims to explore the association between periodontitis and CVD, and the impact of periodontal therapy on cardiovascular health. Methods: This review synthesized findings from preclinical and clinical studies, without publication year restrictions, examining periodontitis and CVD through various lenses. Scientific databases were inspected with keywords related to periodontitis and CVD. Results: The review identifies a substantial association between periodontitis and an increased risk of several CVD, supported by both epidemiological and interventional studies. Results suggest the complexity of the relationship, influenced by factors like the severity of periodontitis and the presence of other systemic conditions. Clinical data indicates that periodontal therapy, particularly non -surgical periodontal therapy, may reduce systemic inflammatory markers and thus may play a role in the primary and secondary prevention of CVD events, highlighting the potential of periodontal therapy to not only maintain oral health but also to modulate cardiovascular risk factors. Conclusions: Current evidence supports a significant association between periodontitis and increased cardiovascular risk, promoting integrated healthcare approaches that consider oral health as a key -component of cardiovascular care and wellbeing
Phenomenology of symmetry breaking from extra dimensions
Motivated by the electroweak hierarchy problem, we consider theories with two
extra dimensions in which the four-dimensional scalar fields are components of
gauge boson in full space. We explore the Nielsen-Olesen instability for SU(N)
on a torus, in the presence of a magnetic background. A field theory approach
is developed, computing explicitly the minimum of the complete effective
potential, including tri-linear and quartic couplings and determining the
symmetries of the stable vacua. We also develop appropriate gauge-fixing terms
when both Kaluza-Klein and Landau levels are present and interacting,
discussing the interplay between the possible six and four dimensional choices.
The equivalence between coordinate dependent and constant Scherk-Schwarz
boundary conditions -associated to either continuous or discrete Wilson lines-
is analyzed.Comment: 39 pages and 8 eps figures. Few changes in section
Brexit or Bremain? : evidence from bubble analysis
We applied the Johansen-Ledoit-Sornette (JLS) model to detect possible bubbles and crashes related to the Brexit/Bremain referendum scheduled for 23rd June 2016. Our implementation includes an enhanced model calibration using Genetic Algorithms. We selected a few historical financial series sensitive to the Brexit/Bremain scenario, representative of multiple asset classes. We found that equity and currency asset classes show no bubble signals, while rates, credit and real estate show super-exponential behaviour and instabilities typical of bubble regime. Our study suggests that, under the JLS model, equity and currency markets do not expect crashes or sharp rises following the referendum results. Instead, rates and credit markets consider the referendum a risky event, expecting either a Bremain scenario or a Brexit scenario edulcorated by central banks intervention. In the case of real estate, a crash is expected, but its relationship with the referendum results is unclear
Polyhydroxyalkanoates production by mixed microbial cultures in sequencing batch reactors operated under different feeding conditions
The production of polyhydroxyalkanoates (PHA) by mixed microbial cultures (MMC) requires a multistage process, whereby the microbial selection of PHA-storing microorganisms plays a key role on the overall performance. A strategy to favor the microbial selection consists in the alternance of excess (feast phase) and absence (famine phase) of the external carbon source. In this work, three runs of a lab-scale Sequencing Batch Reactor (SBR) operated under different working conditions for the establishment of the feast and famine (F/F) regime were analyzed. A fixed organic loading rate of 4.25 gCOD (Chemical Oxygen Demand)/L d, and a fixed cycle length of 12 h were applied to the SBR. The F/F regime consisted of fully aerobic dynamic (ADF) or aerobic/anoxic (AE/ANOX) conditions. Results showed an intracellular PHA content as high as 40 ± 2 (%, w/w) when ADF conditions were applied with the organic feeding solution made of acetate (85 % on COD basis) and propionic (15%) acids. The hydroxyvalerate content in the stored polymer increased (from 25 ± 1 to 41 ± 3, %
w/w) by increasing the propionic fraction (up to 35%) in the feeding solution. The AE/ANOX condition resulted in a lower PHA-storing ability which warrants further investigations
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