8,508 research outputs found
Motion of charged test particles in Reissner--Nordstr\"om spacetime
We investigate the circular motion of charged test particles in the
gravitational field of a charged mass described by the Reissner-Nordstr\"om
(RN) spacetime. We study in detail all the spatial regions where circular
motion is allowed around either black holes or naked singularities. The effects
of repulsive gravity are discussed by finding all the circles at which a
particle can have vanishing angular momentum. We show that the geometric
structure of stable accretion disks, made of only test particles moving along
circular orbits around the central body, allows us to clearly distinguish
between black holes and naked singularities.Comment: 58 pages, 41 figures. To be published in Phys. Rev. D. This work
follows the paper "Circular motion of neutral test particles in
Reissner-Nordstr\'om spacetime" published in Phys.\ Rev.\ D \ Vol.83, No.2
with DOI: 10.1103/PhysRevD.83.024021 (arXiv:1012.5411v1 [astro-ph.HE]
Habitual accountability routines in the boardroom: How boards balance control and collaboration
open3siCorporate accountability is a complex chain of reporting that reaches from external stakeholders into the organization’s management structure. The transition from external to internal accountability mechanisms primarily occurs at the board of directors. Yet outside of incentive mechanisms, we know surprisingly little about how internal actors (management) are held to account by the representatives of external shareholders (the board). This paper explores the process of accountability at this transition point by documenting the routines used by boards to hold the firm’s management to account. In so doing we develop our understanding of the important transition between internal and external firm accountability.embargoed_20190401Nicholson, Gavin; Pugliese, Amedeo; Bezemer, Pieter JanNicholson, Gavin; Pugliese, Amedeo; Bezemer, Pieter Ja
The Sensoria Approach Applied to the Finance Case Study
This chapter provides an effective implementation of (part of) the Sensoria approach, specifically modelling and formal analysis of service-oriented software based on mathematically founded techniques. The ‘Finance case study’
is used as a test bed for demonstrating the feasibility and effectiveness of the use of the process calculus COWS and some of its related analysis techniques and tools. In particular, we report the results of an application of a temporal logic and its model checker for expressing and checking functional properties of services and a type system for guaranteeing confidentiality properties of services
Recommended from our members
Grid computing technologies for renewable electricity generator monitoring and control
In this paper we discuss the use of real-time Grid computing for the monitoring, control and simulation of renewable electricity generators and their associated electrical networks. We discuss briefly the architectural design of GRIDCC and how we have integrated a number of real (solar, CHP) and simulated conventional power generators into the GRIDCC environment. A local weather station has also been attached to an Instrument Manager to alert experts appropriately when the Solar Array is not generating. The customised remote control and monitoring environment (a virtual control room), distributed using a standard web server, is discussed
Circular motion of neutral test particles in Reissner-Nordstr\"om spacetime
We investigate the motion of neutral test particles in the gravitational
field of a mass with charge described by the Reissner-Nordstr\"om (RN)
spacetime. We focus on the study of circular stable and unstable orbits around
configurations describing either black holes or naked singularities. We show
that at the classical radius, defined as , there exist orbits with zero
angular momentum due to the presence of repulsive gravity. The analysis of the
stability of circular orbits indicates that black holes are characterized by a
continuous region of stability. In the case of naked singularities, the region
of stability can split into two non-connected regions inside which test
particles move along stable circular orbits.Comment: 23 pages, 22 figures. To be published Phys. Rev.
Evaluating the expression of urokinase and tissue leukocyte being in benign and malignant breast disease
Introduction: Our objectives is to show that the expression of uPA leukocyte could be considered, in the future, as a marker of
the expression of uPA in the malignant tissue and therefore a potential indicator of prognosis.
Methods: We examined the expression of uPa in leukocytes and tissues of three groups of women: with breast cancer; with
benign breast lesion and healthy women (control group). We used RT Real Time PCR assay. The expression of urokinase is
significantly higher in malignant breast lumps compared to benign lesions. However, in women with carcinoma of the breast,
malignant tissue expresses higher amounts of uPA than the healthy counterpart. There are no statistically significant differences in
the expression of uPA, between tissues taken from women with benign lesions. The lymphocytes taken from healthy volunteers
show a level of expression of uPA significantly lower than the other tested samples Lymphocytes extracted from cancer patients
express higher amounts of uPA compared to lymphocytes belonging to women with benign breast lesions. The expression of uPA
was compared with the clinical and biological parameters commonly used in clinical practice for the definition of the prognosis.
The only exception found, concerns those tumors characterized by the simultaneous negativity for estrogen receptors,
progesterone and HER2 (state of triple negative), in which the expression of uPA is very high.
Results and conclusions: Our data show that uPA expressed by leukocytes of each individual patient is the mirror image of the
one expressed by malignant nodular uPA.Introduction: Our objectives is to show that the expression of uPA leukocyte could be considered, in the future, as a marker of
the expression of uPA in the malignant tissue and therefore a potential indicator of prognosis.
Methods: We examined the expression of uPa in leukocytes and tissues of three groups of women: with breast cancer; with
benign breast lesion and healthy women (control group). We used RT Real Time PCR assay. The expression of urokinase is
significantly higher in malignant breast lumps compared to benign lesions. However, in women with carcinoma of the breast,
malignant tissue expresses higher amounts of uPA than the healthy counterpart. There are no statistically significant differences in
the expression of uPA, between tissues taken from women with benign lesions. The lymphocytes taken from healthy volunteers
show a level of expression of uPA significantly lower than the other tested samples Lymphocytes extracted from cancer patients
express higher amounts of uPA compared to lymphocytes belonging to women with benign breast lesions. The expression of uPA
was compared with the clinical and biological parameters commonly used in clinical practice for the definition of the prognosis.
The only exception found, concerns those tumors characterized by the simultaneous negativity for estrogen receptors,
progesterone and HER2 (state of triple negative), in which the expression of uPA is very high.
Results and conclusions: Our data show that uPA expressed by leukocytes of each individual patient is the mirror image of the
one expressed by malignant nodular uPA
Boosted Cross-Linking and Characterization of High-Performing Self-Assembling Peptides
Tissue engineering (TE) strategies require the design and characterization of novel biomaterials capable of mimicking the physiological microenvironments of the tissues to be regenerated. As such, implantable materials should be biomimetic, nanostructured and with mechanical properties approximating those of the target organ/tissue. Self-assembling peptides (SAPs) are biomimetic nanomaterials that can be readily synthesized and customized to match the requirements of some TE applications, but the weak interactions involved in the self-assembling phenomenon make them soft hydrogels unsuited for the regeneration of medium-to-hard tissues. In this work, we moved significant steps forward in the field of chemical cross-linked SAPs towards the goal of stiff peptidic materials suited for the regeneration of several tissues. Novel SAPs were designed and characterized to boost the 4-(N-Maleimidomethyl) cyclohexane-1-carboxylic acid 3-sulpho-N-hydroxysuccinimide ester (Sulfo-SMCC) mediated cross-linking reaction, where they reached G′ values of ~500 kPa. An additional orthogonal cross-linking was also effective and allowed to top remarkable G′ values of 840 kPa. We demonstrated that cross-linking fastened the pre-existing self-aggregated nanostructures, and at the same time, a strong presence of ß-structures is necessary for an effective cross-linking of (LKLK)3-based SAPs. Combining strong SAP design and orthogonal cross-linking reactions, we brought SAP stiffness closer to the MPa threshold, and as such, we opened the door of the regeneration of skin, muscle and lung to biomimetic SAP technology
A case of primary Hodgkin's lymphoma of the parotid gland. Case report and differentian diagnosis from Kuttner's Syndrom
Abstract
We report a rare case of primary Hodgkin’s lymphoma (HL) of the submandibular
gland, with initially diagnosis of Kuttner’s Syndrom. A 48 years old man was referred to our hospital foe evaluation
of a submandibular mass. Although the initial Fine Needle Aspiration and subsequent cytology was highly suggestive for a cronic sialadenitis with lymphoid cells.
After surgical gland removal we obtained a definitive diagnosis of Hodgkin’s lymphoma in
submandibular gland a seat where the most common lymphoma tipe is B
Heterogeneous pair approximation for voter models on networks
For models whose evolution takes place on a network it is often necessary to
augment the mean-field approach by considering explicitly the degree dependence
of average quantities (heterogeneous mean-field). Here we introduce the degree
dependence in the pair approximation (heterogeneous pair approximation) for
analyzing voter models on uncorrelated networks. This approach gives an
essentially exact description of the dynamics, correcting some inaccurate
results of previous approaches. The heterogeneous pair approximation introduced
here can be applied in full generality to many other processes on complex
networks.Comment: 6 pages, 6 figures, published versio
- …