Policy based roles for distributed systems security

Distributed systems are increasingly being used in commercial environments necessitating the development of trustworthy and reliable security mechanisms. There is often no clear informal or formal specification of enterprise authorisation policies and no tools to translate policy specifications to access control implementation mechanisms such as capabilities or Access Control Lists. It is thus difficult to analyse the policy to detect conflicts or flaws and it is difficult to verify that the implementation corresponds to the policy specification. We present in this paper a framework for the specification of management policies. We are concerned with two types of policies: obligations which specify what activities a manager or agent must or must not perform on a set of target objects and authorisations which specify what activities a subject (manager or agent) can or can not perform on the set of target objects. Management policies are then grouped into roles reflecting the organisation..

Hospitalization causes due to iron overload in beta-Thalassemia in Gorgan, Iran

Objective: To evaluate causes of hospitalization (due to complications of iron overload and other causes) in beta-Thalassemic patients. Methodology: This study was performed on 244 patients with major beta-Thalassemia admitted in Taleghani hospital of Gorgan between 2000 and 2007. Causes of hospitalization (due to complications of iron overload and other causes) were evaluated. Data were analyzed with SPSS software. Results: The most common causes of hospitalization due to iron overload were diabetes mellitus (31.6%) and heart failure (16.4%). The most common clinical findings were weakness and fatigue. Conclusion: We perceive increased frequency of diabetes mellitus in this center compared to other studies in Iran and abroad. Therefore glucose tolerance test and genotypic research for IVS II nt 745 are recommended in Thalassemic patient in this area

On the CR transversality of holomorphic maps into hyperquadrics

Let $M_\ell$ be a smooth Levi-nondegenerate hypersurface of signature $\ell$ in $\mathbf C^n$ with $n\ge 3$, and write $H_\ell^N$ for the standard hyperquadric of the same signature in $\mathbf C^N$ with $N-n< \frac{n-1}{2}$. Let $F$ be a holomorphic map sending $M_\ell$ into $H_\ell^N$. Assume $F$ does not send a neighborhood of $M_\ell$ in $\mathbf C^n$ into $H_\ell^N$. We show that $F$ is necessarily CR transversal to $M_\ell$ at any point. Equivalently, we show that $F$ is a local CR embedding from $M_\ell$ into $H_\ell^N$.Comment: To appear in Abel Symposia, dedicated to Professor Yum-Tong Siu on the occasion of his 70th birthda

The Pioneer Anomaly and a Machian Universe

We discuss astronomical and astrophysical evidence, which we relate to the principle of zero-total energy of the Universe, that imply several relations among the mass M, the radius R and the angular momentum L of a "large" sphere representing a Machian Universe. By calculating the angular speed, we find a peculiar centripetal acceleration for the Universe. This is an ubiquituous property that relates one observer to any observable. It turns out that this is exactly the anomalous acceleration observed on the Pioneers spaceships. We have thus, shown that this anomaly is to be considered a property of the Machian Universe. We discuss several possible arguments against our proposal.Comment: 6 pages including front page. Publishe

The trans-sialidase from Trypanosoma cruzi induces thrombocytopenia during acute Chagas' disease by reducing the platelet sialic acid contents

Strong thrombocytopenia is observed during acute infection with Trypanosoma cruzi, the parasitic protozoan agent of American trypanosomiasis or Chagas' disease. The parasite sheds trans-sialidase, an enzyme able to mobilize the sialyl residues on cell surfaces, which is distributed in blood and is a virulence factor. Since the sialic acid content on the platelet surface is crucial for determining the half-life of platelets in blood, we examined the possible involvement of the parasite-derived enzyme in thrombocytopenia induction. We found that a single intravenous injection of trans-sialidase into naïve mice reduced the platelet count by 50%, a transient effect that lasted as long as the enzyme remained in the blood. CD43(−/−) mice were affected to a similar extent. When green fluorescent protein-expressing platelets were treated in vitro with trans-sialidase, their sialic acid content was reduced together with their life span, as determined after transfusion into naïve animals. No apparent deleterious effect on the bone marrow was observed. A central role for Kupffer cells in the clearance of trans-sialidase-altered platelets was revealed after phagocyte depletion by administration of clodronate-containing liposomes and splenectomy. Consistent with this, parasite strains known to exhibit more trans-sialidase activity induced heavier thrombocytopenia. Finally, the passive transfer of a trans-sialidase-neutralizing monoclonal antibody to infected animals prevented the clearance of transfused platelets. Results reported here strongly support the hypothesis that the trans-sialidase is the virulence factor that, after depleting the sialic acid content of platelets, induces the accelerated clearance of the platelets that leads to the thrombocytopenia observed during acute Chagas' disease

Formal and finite order equivalences

We show that two families of germs of real-analytic subsets in $C^{n}$ are formally equivalent if and only if they are equivalent of any finite order. We further apply the same technique to obtain analogous statements for equivalences of real-analytic self-maps and vector fields under conjugations. On the other hand, we provide an example of two sets of germs of smooth curves that are equivalent of any finite order but not formally equivalent

Determinants of poverty in Kenya : a household level analysis

poverty;statistical analysis;measurement;Kenya;household surveys

A Security Framework Supporting Domain Based Access Control in Distributed Systems

Accepted versio

Thin-shell wormholes: Linearization stability

The class of spherically-symmetric thin-shell wormholes provides a particularly elegant collection of exemplars for the study of traversable Lorentzian wormholes. In the present paper we consider linearized (spherically symmetric) perturbations around some assumed static solution of the Einstein field equations. This permits us to relate stability issues to the (linearized) equation of state of the exotic matter which is located at the wormhole throat.Comment: 4 pages; ReV_TeX 3.0; one postscript figur

COVID-19 Contagion among Communities with Limited English Proficiency: Lesson from Volunteerism

The COVID-19 affects all communities in the United States, but its impact differs from one community to another. Undoubtedly, the vulnerable populations are more impacted than others, especially refugees and immigrants. This study seeks to understand the impact of COVID-19 on marginalized communities and the need to communicate health-related information equally. A lesson learned from observation during an ongoing pandemic, including what I learned through my volunteer work between mid-March and August 2020. The study finds that neighbors with limited English Proficiency (LEP) and limited education could quickly transfer the COVID-19 virus to another neighbor with high income and well-educated. Disparities in access to care and underlying causes among LEP communities may lead to spreading the virus. Making health information available in different languages and more TV channels and radios that disseminate COVID-19 information in multiple languages is essential. It is imperative for public health during the resiliency process to thoroughly prepare and consider vulnerable communities’ health and need to legislate proper health communication and education for all for any possible pandemic in the future