32 research outputs found
A Late-Byzantine hagiographer: Philotheos Kokkinos and his Vitae of Contemporary Saints
No full textThis dissertation offers the first systematic historical contextualization and literary
analysis of the five saints’ lives composed by Philotheos Kokkinos (ca. 1300–1378)
for his contemporaries Nikodemos the Younger, Sabas the Younger, Isidore
Boucheir, Germanos Maroules, and Gregory Palamas. Notwithstanding Kokkinos’
prominent role in the political and ecclesiastical scene of fourteenth-century
Byzantium, as well as the size and significance of his hagiographic oeuvre, both the
hagiographer and his saints’ lives have received surprisingly little scholarly attention.
My dissertation fills this gap and shows Kokkinos as a gifted hagiographer who
played a leading role, both through his ecclesiastical authority and hagiographic
discourse, in orchestrating the societal breakthrough of hesychast theology that has
remained at the core of Christian Orthodoxy up to this day.
The dissertation is structured in three parts. The first, Philotheos Kokkinos
and His OEuvre, offers an extensive biographical portrait of Kokkinos, introduces his
literary oeuvre, and discusses its manuscript tradition. A thorough palaeographical
investigation of fourteenth-century codices carrying his writings reveals Kokkinos’
active involvement in the process of copying, reviewing, and publishing his own
works. This section includes an analysis of the “author’s edition” manuscript
Marcianus graecus 582, and presents its unusual fate. Moreover, Part I establishes
the chronology of Kokkinos’ vitae of contemporary saints and offers biographical
sketches of his heroes, highlighting their relationship to their hagiographer. The
second part, Narratological Analysis of Kokkinos’ Vitae of Contemporary Saints,
constitutes the first comprehensive analysis of Kokkinos’ narrative technique. It first
discusses the types of hagiographic composition (‘hagiographic genre’) Kokkinos
employed for his saints’ lives (hypomnema, bios kai politeia, and logos), and then it
offers a detailed investigation that sheds light on the organization of the narrative in
Kokkinos’ vitae and his use of specific narrative devices. This includes a discussion
of hesychastic elements couched in the narrative. Part II concludes with
considerations on Kokkinos’ style and intended audience. The third part, Saints and
Society, begins with a detailed quantitative and qualitative analysis of the miracle
accounts Kokkinos wove in his saints’ lives. This considers the miracle typology,
types of afflictions, methods of healing, and the demographic characteristics of the
beneficiaries (such as age, gender, and social status), revealing that Kokkinos shows
a predilection for including miracles for members of the aristocracy. Second, it
presents Kokkinos’ view on the relationship between the imperial office and
ecclesiastical authority by analysing how he portrays the emperor(s) in his vitae.
Moreover, this part addresses the saints’ encounters with the “other” (Muslims and
Latins), revealing Kokkinos’ nuanced understanding of the threats and opportunities
raised by these interactions. Finally, it makes the claim that through his saints’ lives
Kokkinos offers models of identification and refuge in the troubled social and
political context of fourteenth-century Byzantium, promoting a spiritual revival of
society. As my dissertation shows, Kokkinos’ vitae of contemporary saints sought to
shape and were shaped by the political and theological disputes of fourteenth-century
Byzantium, especially those surrounding hesychasm. Their analysis offers insights
into the thought-world of their author and sheds more light on the late-Byzantine
religious and cultural context of their production.
The dissertation is equipped with six technical appendices presenting the
chronology of Kokkinos’ life and works, the narrative structure of his vitae of
contemporary saints, a critical edition of the preface of his hitherto unedited Logos
on All Saints (BHG 1617g), a transcription of two hitherto unedited prayers
Kokkinos addressed to the emperors, the content of Marc. gr. 582 and Kokkinos’
autograph interventions, and manuscript plates
The Dirichlet problem for elliptic systems with data in Köthe function spaces
No full textWe show that the boundedness of the Hardy-Littlewood maximal operator on a Kothe function space X and on its Kothe dual X is equivalent to the well-posedness of the X-Dirichlet and X-Dirichlet problems in Rn + in the class of all second-order, homogeneous, elliptic systems, with constant complex coefficients. As a consequence, we obtain that the Dirichlet problem for such systems is well-posed for boundary data in Lebesgue spaces, variable exponent Lebesgue spaces, Lorentz spaces, Zygmund spaces, as well as their weighted versions. We also discuss a version of the aforementioned result which contains, as a particular case, the Dirichlet problem for elliptic systems with data in the classical Hardy space H1, and the Beurling-Hardy space HAp for p € (1,∞). Based on the well-posedness of the Lp-Dirichlet problem we then prove the uniqueness of the Poisson kernel associated with such systems, as well as the fact that they generate a strongly continuous semigroup in natural settings. Finally, we establish a general Fatou type theorem guaranteeing the existence of the pointwise nontangential boundary trace for null-solutions of such systems.The First author has been supported in part by MINECO Grant MTM2010-16518,
ICMAT Severo Ochoa project SEV-2011-0087. He also acknowledges that the research
leading to these results has received funding from the European Research Council under
the European Union's Seventh Framework Programme (FP7/2007-2013)/ ERC agreement
no. 615112 HAPDEGMT. The second author has been supported in part by a Simons
Foundation grant #200750, the third author has been supported in part by US NSF grant
#0547944, while the fourth author has been supported in part by the Simons Foundation
grant #281566, and by a University of Missouri Research Leave grantPeer reviewe
On the L p-Poisson Semigroup Associated with Elliptic Systems
No full textWe study the infinitesimal generator of the Poisson semigroup in L associated with homogeneous, second-order, strongly elliptic systems with constant complex coefficients in the upper-half space, which is proved to be the Dirichlet-to-Normal mapping in this setting. Also, its domain is identified as the linear subspace of the L-based Sobolev space of order one on the boundary of the upper-half space consisting of functions for which the Regularity problem is solvable. Moreover, for a class of systems containing the Lamé system, as well as all second-order, scalar elliptic operators, with constant complex coefficients, the action of the infinitesimal generator is explicitly described in terms of singular integral operators whose kernels involve first-order derivatives of the canonical fundamental solution of the given system. Furthermore, arbitrary powers of the infinitesimal generator of the said Poisson semigroup are also described in terms of higher order Sobolev spaces and a higher order Regularity problem for the system in question. Finally, we indicate how our techniques may be adapted to treat the case of higher order systems in graph Lipschitz domains.The first author acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa Programme for Centres of Excellence in R&D” (SEV-2015-0554). He also acknowledges that the research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ ERC agreement no. 615112 HAPDEGMT. The second author has been supported in part by a Simons Foundation grant # 426669, the third author has been supported in part by the Simons Foundation grant #318658, while the fourth author has been supported in part by the Simons Foundation grant # 281566, and by a University of Missouri Research Leave grant
The BMO-Dirichlet problem for elliptic systems in the upper half-space and quantitative characterizations of VMO
No full textWe prove that for any homogeneous, second-order, constant complex coefficient elliptic system L in ℝ, the Dirichlet problem in ℝ with boundary data in BMO.ℝ/ is well-posed in the class of functions u for which the Littlewood-Paley measure associated with u, namely dμ(x', t):=| ∇u(x',t)| t dx' dt; is a Carleson measure in ℝ. In the process we establish a Fatou-type theorem guaranteeing the existence of the pointwise nontangential boundary trace for smooth null-solutions u of such systems satisfying the said Carleson measure condition. In concert, these results imply that the space BMO(ℝ) can be characterized as the collection of nontangential pointwise traces of smooth null-solutions u to the elliptic system L with the property that μ is a Carleson measure in ℝ. We also establish a regularity result for the BMO-Dirichlet problem in the upper half-space, to the effect that the nontangential pointwise trace on the boundary of ℝ of any given smooth nullsolutions u of L in ℝ satisfying the above Carleson measure condition actually belongs to Sarason's space VMO.ℝ/ if and only if μ(T(Q))/|Q|→0 as |Q|→0, uniformly with respect to the location of the cubeQ⊂ℝ (where T(Q) is the Carleson box associated withQ, and |Q| denotes the Euclidean volume of Q). Moreover, we are able to establish the well-posedness of the Dirichlet problem in ℝ C for a system L as above in the case when the boundary data are prescribed in Morrey-Campanato spaces in ℝ. In such a scenario, the solution u is required to satisfy a vanishing Carleson measure condition of fractional order. By relying on these well-posedness and regularity results we succeed in producing characterizations of the space VMO as the closure in BMO of classes of smooth functions contained in BMO within which uniform continuity may be suitably quantified (such as the class of smooth functions satisfying a Hölder or Lipschitz condition). This improves on Sarason's classical result describing VMO as the closure in BMO of the space of uniformly continuous functions with bounded mean oscillations. In turn, this allows us to show that any Calderón-Zygmund operator T satisfying T (1) = 0 extends as a linear and bounded mapping from VMO (modulo constants) into itself. In turn, this is used to describe algebras of singular integral operators on VMO, and to characterize the membership to VMO via the action of various classes of singular integral operators.The first author would like to express his gratitude to the University of Missouri-Columbia (USA), for its support and hospitality while he was visiting this institution. The first author acknowledges financial support
from the Spanish Ministry of Economy and Competitiveness, through the \Severo Ochoa Programme for Centres of Excellence in R&D" (SEV-2015-0554). He also acknowledges that the research leading to these results has
received funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ ERC agreement no. 615112 HAPDEGMT. The second author has been supported in part by the Simons Foundation grant #426669, the third author has been supported in part by the Simons Foundation grant #318658, while the fourth author has been supported in part by the Simons Foundation grant #281566, and by a University of Missouri Research Leave grant.Peer Reviewe
Fatou-type theorems and boundary value problems for elliptic systems in the upper half-space
No full textWe survey recent progress in a program which to date has produced [18]-
[25], aimed at proving general Fatou-type results and establishing the well-posedness
of a variety of boundary value problems in the upper half-space Rn
+ for second-order, homogeneous, constant complex coe cient, elliptic systems L, formulated in a manner
that emphasizes pointwise nontangential boundary traces of the null-solutions of L in Rn +.
1The rst author acknowledges that the research leading to these results has received funding from the
European Research Council under the European Union's Seventh Framework Programme (FP7/2007- 2013)/ERC agreement no. 615112 HAPDEGMT. He also acknowledges nancial support from the Spanish Ministry of Economy and Competitiveness, through the \Severo Ochoa Programme for Centres of Excellence in R&D" (SEV-2015-0554).Peer reviewe
Wrist Circumference: An Independent Predictor of Both Insulin Resistance and Chronic Kidney Disease in an Elderly Population
No full textAbstract Background and aim: It was recently reported that wrist circumference is associated with insulin resistance (IR) both in children and adults. We aimed to evaluate whether wrist circumference is a useful anthropometrical parameter for the evaluation of IR in an elderly population. Material and method: We performed a study on 40 subjects, 20 with type 2 diabetes (T2D) and 20 control subjects. IR was evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR). We measured the following anthropometrical parameters: weight, height, waist circumference (WC), hip circumference, wrist circumference, waist to hip ratio (WHR), waist to height ratio (WHtR), body mass index (BMI) and body adiposity index (BAI). Results: We found statistically significant differences between the subjects with T2D and the control group for all the analyzed parameters. Statistically significant correlations between all the anthropometrical parameters and HOMA-IR were observed. However, only WC was an independent predictor of IR. Wrist circumference was the only parameter negatively correlated with the estimated glomerular filtration rate (eGFR). Furthermore, this measurement was an independent predictor of chronic kidney disease (CKD) in the studied subjects. Conclusion: Wrist circumference can be used in the general practice as a surrogate marker of IR in the elderly, being both easily determined and a cost-free method</jats:p
Is Non Dipping Hypertension Associated with Dyslipidemia, Type 2 Diabetes or Chronic Kidney Disease?
No full textAbstract Background and aims. Hypertension and dyslipidemia (DLP) increase the risk of cardiovascular diseases (CVD), especially in patients with chronic kidney disease (CKD). A non dipping pattern is very common in CKD. The aim of the study was to determine whether there is a difference between dipping/non dipping hypertension in subjects with CKD and DLP with or without lipid-lowering therapy (LLT). Material and methods. We performed a retrospective study that included 129 subjects from the Nephrology- Hypertension Out-patient Department of the University Campus Bio-Medico, Rome from January 2011 to April 2013. Results. From a total of 129 CKD subjects, 73 (56.59%) subjects had a non dipping pattern and 56 (43.41%) had a dipper pattern. We found statistically significant differences between the dipping and non-dipping pattern in subjects with CKD stages 1-2 versus stages 3-4 (p=0.018). When we analyzed the association between non-dipping status with DLP and type 2 diabetes (T2D), we did not find a statistically significant result. Conclusions. Only CKD significantly influenced the dipping/non dipping pattern in the study group</jats:p
New Challenges of Treatment for Locally Advanced Head and Neck Cancers in the Covid-19 Pandemic Era
No full textLocally advanced head and neck cancer is a unique challenge for cancer management in the Covid-19 situation. The negative consequences of delaying radio-chemotherapy treatment make it necessary to prioritize these patients, the continuation of radiotherapy being indicated even if SARS-CoV-2 infection is confirmed in the case of patients with moderate and mild symptoms. For an early scenario, the standard chemo-radiotherapy using simultaneous integrated boost (SIB) technique is the preferred option, because it reduces the overall treatment time. For a late scenario with limited resources, hypo-fractionated treatment, with possible omission of chemotherapy for elderly patients and for those who have comorbidities, is recommended. Concurrent chemotherapy is controversial for dose values >2.4 Gy per fraction. The implementation of hypo-fractionated regimens should be based on a careful assessment of dose-volume constraints for organs at risks (OARs), using recommendations from clinical trials or dose conversion based on the linear-quadratic (LQ) model. Induction chemotherapy is not considered the optimal solution in this situation because of the risk of immunosuppression even though in selected groups of patients TPF regimen may bring benefits. Although the MACH-NC meta-analysis of chemotherapy in head and neck cancers did not demonstrate the superiority of induction chemotherapy over concurrent chemoradiotherapy, an induction regimen could be considered for cases with an increased risk of metastasis even in the case of a possible Covid-19 pandemic scenario
Connectivity conditions and boundary Poincaré inequalities
No full textInspired by recent work of Mourgoglou and the second named author, and earlier work of Hofmann, Mitrea and Taylor, we consider connections between the local John condition, the Harnack chain condition and weak boundary Poincaré inequalities in open sets , with codimension Ahlfors--David regular boundaries. First, we prove that if satisfies both the local John condition and the exterior corkscrew condition, then also satisfies the Harnack chain condition (and hence, is a chord-arc domain). Second, we show that if is a -sided chord-arc domain, then the boundary supports a Heinonen--Koskela type weak -Poincaré inequality. We also construct an example of a set such that the boundary is Ahlfors--David regular and supports a weak boundary -Poincaré inequality but is not a chord-arc domain. Our proofs utilize significant advances in particularly harmonic measure, uniform rectifiability and metric Poincaré theories.40 pages, 5 figures. v3: accepted version; updated grant information and picture formats. To appear in Analysis & PD
