831 research outputs found
Enhanced ULF radiation observed by DEMETER two months around the strong 2010 Haiti earthquake
In this paper we study the energy of ULF electromagnetic waves that have been
recorded by the satellite DEMETER, during its passing over Haiti before and
after a destructive earthquake. This earthquake occurred on 12/1/2010, at
geographic Latitude 18.46o and Longitude 287.47o, with Magnitude 7.0 R.
Specifically, we are focusing on the variations of energy of Ez-electric field
component concerning a time period of 100 days before and 50 days after the
strong earthquake. In order to study these variations, we developed a novel
method that can be divided in two stages: first we filter the signal keeping
only the very low frequencies and afterwards we eliminate its trend using
techniques of Singular Spectrum Analysis, combined with a third-degree
polynomial filter. As it is shown, a significant increase in energy is observed
for the time interval of 30 days before the strong earthquake. This result
clearly indicates that the change in the energy of ULF electromagnetic waves
could be related to strong precursory earthquake phenomena. Moreover, changes
in energy were also observed 25 days after the strong earthquake associated
with strong aftershock activity. Finally, we present results concerning the
comparison in changes in Energy during night and day passes of the satellite
over Haiti, which showed differences in the mean energy values, but similar
results as far as the rate of energy change is concerned.Comment: 16 pages, 7 figures, submitted to NHES
Thyroid hormones enhance the biomechanical functionality of scaffold-free neocartilage
IntroductionThe aim of this study was to investigate the effects of thyroid hormones tri-iodothyronine (T3), thyroxine (T4), and parathyroid hormone (PTH) from the parathyroid glands, known to regulate the developing limb and growth plate, on articular cartilage tissue regeneration using a scaffold-free in vitro model.MethodsIn Phase 1, T3, T4, or PTH was applied during weeks 1 or 3 of a 4-week neocartilage culture. Phase 2 employed T3 during week 1, followed by PTH during week 2, 3, or weeks 2 to 4, to further enhance tissue properties. Resultant neotissues were evaluated biochemically, mechanically, and histologically.ResultsIn Phase 1, T3 and T4 treatment during week 1 resulted in significantly enhanced collagen production; 1.4- and 1.3-times untreated neocartilage. Compressive and tensile properties were also significantly increased, as compared to untreated and PTH groups. PTH treatment did not result in notable tissue changes. As T3 induces hypertrophy, in Phase 2, PTH (known to suppress hypertrophy) was applied sequentially after T3. Excitingly, sequential treatment with T3 and PTH reduced expression of hypertrophic marker collagen X, while yielding neocartilage with significantly enhanced functional properties. Specifically, in comparison to no hormone application, these hormones increased compressive and tensile moduli 4.0-fold and 3.1-fold, respectively.ConclusionsThis study demonstrated that T3, together with PTH, when applied in a scaffold-free model of cartilage formation, significantly enhanced functional properties. The novel use of these thyroid hormones generates mechanically robust neocartilage via the use of a scaffold-free tissue engineering model
Geochemical mapping of urban soils in Athens, Greece - Preliminary results
Η αστική γεωχημεία είναι ένας αναπτυσσόμενος επιστημονικός τομέας κυρίως λόγω των περιβαλλοντικών επιπτώσεων από την εξάπλωση των πόλεων και την αύξηση του αστικού πληθυσμού. Η παρούσα εργασία έχει ως στόχο τη γεωχημική χαρτογράφηση των επιφανειακών (0-10 cm) εδαφών της Αθήνας με έμφαση στη χωρική κατανομή δυνητικά βλαβερών χημικών στοιχείων. Η δειγματοληψία υπαίθρου πραγματοποιήθηκε βάσει τετραγωνικού κανάβου ισοδιάστασης 1 km και κάλυψε συνολική έκταση περίπου 200 km2, με προτεραιότητα σε παιδικές χαρές, σχολεία και πάρκα. Αναλύθηκαν320 εδαφικά δείγματα κοκκομετρίας < 100 μm με την τεχνική της φασματοσκοπίας ατομικής απορρόφησης μετά από διαλυτοποίηση με βασιλικό ύδωρ και προσδιορί- στηκαν τα στοιχεία Pb, Zn, Cu, Cd, Cr, Ni, Co και Mn. Οι μέσες συγκεντρώσεις των στοιχείων Pb (62 mg/kg), Cu (36 mg/kg), Zn (91 mg/kg) και Mn (465 mg/kg) είναι χαμηλότερες των αντίστοιχων συγκεντρώσεων άλλων Ευρωπαϊκών πόλεων ενώ οι συγκεντρώσεις των Cr (74 mg/kg), Ni (89 mg/kg) και Co (16 mg/kg) υψηλότερες. Το γεωχημικό ανάγλυφο αποτυπώθηκε σε περιβάλλον ΓΣΠ δίνοντας τη δυνατότητα προσδιορισμού διαφορετικών πηγών των στοιχείων. Τα αποτελέσματα της έρευνας συμβάλουν στην εκτίμηση της ποιότητας των εδαφών της Αθήνας και αποτελούν πολύτιμο εργαλείο στην αναγνώριση περιοχών περιβαλλοντικής επικινδυνότητας.Urban geochemistry is a fast growing scientific discipline mainly because of the profound impact of large cities on the environment as well as the increase in the world’s urban population. The present study aims to produce the urban geochemical map of Athens, based on multi-element analysis of surface soils (0-10 cm) with emphasis in the spatial distribution of potentially harmful elements (PHEs). Soil sampling was based on a regular 1km x 1km grid, laid over the survey area covering more than 200 km2. Sampling locations within the grid cells were selected giving priority to playgrounds, schools and urban parks. The < 100 μm fraction of a total of 320 soil samples were analysed by Flame Atomic Absorption Spectroscopy for Pb, Zn, Cu, Cd, Cr, Ni, Co and Mn after aqua regia dissolution. Average content of Pb (62 mg/kg), Cu (36 mg/kg), Zn (91 mg/kg) and Mn (465 mg/kg) in soil was lower than reported concentrations from other European cities while Cr (74 mg/kg), Ni (89 mg/kg) and Co (16 mg/kg) were relatively enriched. Geochemical maps were plotted within GIS enabling recognition of spatial trends in elemental concentrations and potential sources of the elements. The research outcome will contribute to the evaluation of quality characteristics of urban soils in Athens and drive attention to areas of any environmental or health risks
The volume-mortality relation for radical cystectomy in England: retrospective analysis of hospital episode statistics
Objectives To investigate the relation between volume and mortality after adjustment for case mix for radical cystectomy in the English healthcare setting using improved statistical methodology, taking into account the institutional and surgeon volume effects and institutional structural and process of care factors
Leadership in cardiac surgery
Despite the efficacy of cardiac surgery, less invasive interventions with more uncertain long-term outcomes are increasingly challenging surgery as first-line treatment for several congenital, degenerative and ischemic cardiac diseases. The specialty must evolve if it is to ensure its future relevance. More importantly, it must evolve to ensure that future patients have access to treatments with proven long-term effectiveness. This cannot be achieved without dynamic leadership; however, our contention is that this is not enough. The demands of a modern surgical career and the importance of the task at hand are such that the serendipitous emergence of traditional charismatic leadership cannot be relied upon to deliver necessary change. We advocate systematic analysis and strategic leadership at a local, national and international level in four key areas: Clinical Care, Research, Education and Training, and Stakeholder Engagement. While we anticipate that exceptional individuals will continue to shape the future of our specialty, the creation of robust structures to deliver collective leadership in these key areas is of paramount importanc
Holographic Penta and Hepta Quark State in Confining Gauge Theories
We study a new embedding solutions of D5 brane in an asymptotic
AdS space-time, which is dual to a confining gauge
theory. The D5 brane is wrapped on as in the case of the vertex of
holographic baryon. However, the solution given here is different from the
usual baryon vertex in the point that it couples to -anti-quarks and
quarks on the opposite two points of , the north and south poles,
respectively. The total quark number of this state is preserved as when
minus one is assigned to anti-quark, then it forms a color singlet like the
baryon. However, this includes anti-quarks and quarks, whose number is larger
than that of the baryon. When we set as , we find the so called penta
and hepta-quark states. We study the dynamical properties of these states by
solving the vertex and string configurations for such states. The mass spectra
of these states and the tension of the stretched vertex are estimated, and they
are compared with that of the baryon.Comment: 24 pages, 6 figure
COL4A5 and LAMA5 variants co-inherited in familial hematuria: Digenic inheritance or genetic modifier effect?
Background: About 40-50% of patients with familial microscopic hematuria (FMH) caused by thin basement membrane nephropathy (TBMN) inherit heterozygous mutations in collagen IV genes (COL4A3, COL4A4). On long follow-up, the full phenotypic spectrum of these patients varies a lot, ranging from isolated MH or MH plus low-grade proteinuria to chronic renal failure of variable degree, including end-stage renal disease (ESRD). Methods: Here, we performed Whole Exome Sequencing (WES) in patients of six families, presenting with autosomal dominant FMH, with or without progression to proteinuria and loss of renal function, all previously found negative for severe collagen IV mutations. Hierarchical filtering of the WES data was performed, followed by mutation prediction analysis, Sanger sequencing and genetic segregation analysis. Results: In one family with four patients, we found evidence for the contribution of two co-inherited variants in two crucial genes expressed in the glomerular basement membrane (GBM); LAMA5-p.Pro1243Leu and COL4A5-p.Asp654Tyr. Mutations in COL4A5 cause classical X-linked Alport Syndrome, while rare mutations in the LAMA5 have been reported in patients with focal segmental glomerulosclerosis. The phenotypic spectrum of the patients includes hematuria, proteinuria, focal segmental glomerulosclerosis, loss of kidney function and renal cortical cysts. Conclusions: A modifier role of LAMA5 on the background of a hypomorphic Alport syndrome causing mutation is a possible explanation of our findings. Digenic inheritance is another scenario, following the concept that mutations at both loci more accurately explain the spectrum of symptoms, but further investigation is needed under this concept. This is the third report linking a LAMA5 variant with human renal disease and expanding the spectrum of genes involved in glomerular pathologies accompanied by familial hematurias. The cystic phenotype overlaps with that of a mouse model, which carried a Lama5 hypomorphic mutation that caused severely reduced Lama5 protein levels and produced kidney cysts. 2018 The Author(s).The work was supported from the Cyprus Research Promotion Foundation through the grant NEW INFRASTRUCTURE/STRATEGIC/0308/24 to CD (co-funded by the European Regional Development Fund and the Republic of Cyprus). The funding body did not contribute to the design of study, collection, analysis and interpretation of data, or in manuscript writing.Scopu
Heavy quarks in a magnetic field
The motion of a heavy charged quark in a magnetic field is analyzed in the
vacuum of strongly coupled CFT. The motion of the quark is dissipative. It
moves in spiral until it eventually comes to rest. The world-sheet geometry is
locally AdS_2 but has a time dependent horizon. The string profile in the
static gauge extends from the boundary till a point where an embedding
singularity exists. Connections with other circular string motions are
established.Comment: (v3) Misprints corrected, discussion on moving horizons improved and
enhance
Philanthropy or solidarity? Ethical dilemmas about humanitarianism in crisis afflicted Greece
That philanthropy perpetuates the conditions that cause inequality is an old argument shared by thinkers such as Karl Marx, Oscar Wilde and Slavoj Zizek. I recorded the same argument in conversations regarding a growing humanitarian concern in austerity-ridden Greece. At the local level a number of solidarity initiatives provide the most impoverished families with humanitarian help. Some citizens participate in such initiatives wholeheartedly, while some other citizens criticize solidarity movements drawing primarily from Marxist-inspired arguments, such as, for example, that humanitarianism rationalises state inaction. The local narratives presented in this article bring forward two parallel possibilities engendered by the humanitarian face of social solidarity: first, its empowering potential (where solidarity initiatives enhance local social awareness), and second, the de-politicisation of the crisis and the experience of suffering (a liability that stems from the effectiveness of humanitarianism in ameliorating only temporarily the superficial consequences of the crisis). These two overlapping possibilities can help us problematise the contextual specificity and strategic employment of humanitarian solidarity in times of austerity
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