117,392 research outputs found
Language Tests in the Arabic-speaking World: Between Ideology and Language Policy
No full textA system of language assessment may be used as a mechanism for affecting language policy. Language tests convey messages and ideologies that regard prestige, priorities and hierarchies, and they generally lead to the suppression of diversity (Shohamy 2007). The relationship between tests and language policy, based mainly on the criteria used for judging language quality through rating scales, guidelines and other frameworks, leads to a view of language as standardized and homogenous. From this perspective, language tests can serve as tools that negotiate and mediate between ideology and practice. In the Arabic-speaking world language tests have only recently been introduced, although very few Arab countries have shown an interest in developing the necessary means to evaluate language performance levels. In this paper the language tests developed by the Arab Academy, the UAE National Center for Assessment (Markaz al-Waṭanī li-l-Qiyās), the Mother Tongue Center (Markaz al-Lisān al-Umm), the Jordan al-Naǧāḥ National University (Ǧāmiʿat al-Naǧāḥ al-Waṭaniyya) and the King Saʿūd University will be taken into consideration in order to determine any ideological orientation in test objectives, content and rationale. Particular attention will be paid to communicative skills within a general framework of linguistic variation in the Arabic-speaking world
The highly conserved nuclear lamin Ig-fold binds to PCNA : its role in DNA replication
No full textThis study provides insights into the role of nuclear lamins in DNA replication. Our data demonstrate that the Ig-fold motif located in the lamin C terminus binds directly to proliferating cell nuclear antigen ( PCNA), the processivity factor necessary for the chain elongation phase of DNA replication. We find that the introduction of a mutation in the Ig-fold, which alters its structure and causes human muscular dystrophy, inhibits PCNA binding. Studies of nuclear assembly and DNA replication show that lamins, PCNA, and chromatin are closely associated in situ. Exposure of replicating nuclei to an excess of the lamin domain containing the Ig-fold inhibits DNA replication in a concentration-dependent fashion. This inhibitory effect is significantly diminished in nuclei exposed to the same domain bearing the Ig-fold mutation. Using the crystal structures of the lamin Ig-fold and PCNA, molecular docking simulations suggest probable interaction sites. These findings also provide insights into the mechanisms underlying the numerous disease-causing mutations located within the lamin Ig-fold
Chemoprevention of colorectal cancer: A role for ursodeoxycholic acid, folate and hormone replacement treatment?
No full textChemoprevention of colorectal cancer has been an intense focus of research for many years. Among the possible candidate agents, ursodeoxycholic acid, folate, and hormone replacement therapy have been recently investigated with conflicting data. Experimental evidence shows that UDCA, folate and HRT target critical molecular events important for colon carcinogenesis. In animal models of sporadic, familial and inflammatory-associated cancers, they have shown to reduce colonic neoplasms. Observational studies have shown compelling evidence of possible protective effects of all three agents. However, randomised-controlled studies have yielded disappointing results, raising the issues of possible harm rather than protective effect for some of them. In this review experimental and clinical data on UDCA, folate and HRT as potential chemopreventive agents are discussed
The use of halogenated precursors for simultaneous DNA and RNA detection by means of immunoelectron and immunofluorescence microscopy.
No full textA Simulation Framework for Virtualized Resources in Cloud Data Center Networks
No full textMany IT companies are embracing the new softwarization paradigm through the adoption of new architecture models, such as software-defined network and network function virtualization, primarily to limit the costs of maintaining and deploying their network infrastructures, by giving the possibility to service/application providers to reconfigure and programmatically perform actions on the network. Accordingly, the dynamic management of the data center networks requires complex operations to ensure high availability and continuous reliability in order to guarantee full functionality of the virtualized resources. In this context, simulator-based approaches are helpful for planning and evaluating the deployment of the cloud data center networking, but existing cloud simulators have several limitations: they have too high overhead for wide-scale data center networks, complex configuration, and too abstract deployment models. For these motivations, we propose DCNs-2, a novel extension for the Ns-2 simulator, as a valid solution to efficiently simulate a cloud network infrastructure, with all the involved entities, such as switches, physical/virtual machines, and racks. The proposed solution not only makes configuration easier, but through extensive tests, we show that its execution overhead is limited to less than 130 MB of memory and the execution time is acceptable even for very wide-scale and complex deployment environments
The audit4cloud platform for auditing the networking performance of public clouds
No full textElastic resource outsourcing is a growing trend that simplifies and makes more efficient the management of resources, by embracing all the features of the execution of services over public clouds, such as high availability and automated scalability management of resources. Therefore, modern enterprise services are increasingly leveraging inter/intra-cloud deployments and the choice of the right cloud provider to support the execution of them becomes a fundamental operational choice. The paper presents our Audit4Cloud platform, an open-source tool for auditing the performance of virtual resources made available by various commercial cloud providers, with specific focus on cloud networking. In particular, we claim that Audit4Cloud is an enabling key in choosing the right cloud vendor as it not only offers the visibility of current values of some significant performance indicators about the offered cloud resources, but also provides users with a complete picture of those performance indicators over time. We have already performed a large experimental campaign by considering primary commercial cloud providers; the collected results show the feasibility of the approach and that Audit4Cloud can play the role of a solid third-party auditing tool to estimate real performance and costs of cloud resources
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Single and Double Colloidal Gold Labeling in Postembedding Immunoelectron Microscopy
No full textImmunocytochemistry is the most diffuse technique to visualize and localize specific biochemical components in cell compartments and tissues. With this method the antigens are tagged by antibodies that can be visualized with appropriate markers attached directly (direct method) or indirectly (indirect method) to them. The colloidal gold marker system (1) is the most widespread immunoelectron microscopy label for postembedding immunocytochemistry. Sections of embedded tissue are incubated with a primary antibody against a particular antigen, which is exposed on the surface of the section, and then with a secondary antibody conjugated to colloidal gold particles of a particular size (indirect method). It is possible to enlarge the colloidal gold size with silver enhancement. This technique is ideal for labeling both intracellular and surface antigens and it can be used for multiple labeling experiments and quantitative studies (2)
Usare la grammatica medievale per l’insegnamento dell’arabo, il caso della struttura soggiacente
No full textIn questo saggio si tenterà di avvicinare la riflessione linguistica araba classica allo studio della grammatica in classe, seguendo il principio secondo il quale lo studio approfondito di regole come quella più centrale nel trattato che andremo ad esaminare, la Risāla fī iʿrāb lā ilàha illā Allàh attribuita a Ibn Hišām al-Anṣārī1, cioè il taqdīr - la forma soggiacente – possa aiutare il discente nella comprensione della sintassi araba, migliorando così la
qualità della comprensione delle analisi sintattiche e dunque le capacità dei discenti per quanto riguarda la lettura e la comprensione e la produzione, scritta soprattutto.
L’autore di questo breve trattato focalizza la sua analisi sulla marca del caso e sulla sintassi del tawḥīd, e in particolare sulla parola Allàh. Dopo aver elencato le diverse opinioni e aspetti in favore delle due vocalizzazioni possibili – marfūʿ e manṣūb - il grammatico fa uno studio puntuale della questione attraverso l’uso di teorie grammaticali che possiamo ancor oggi
considerare avanzate e, nell’ottica dell’insegnamento della lingua araba, incredibilmente argute.
Inizieremo con lo studio del trattato, evidenziandone prima la struttura e poi addentrandoci nel tema più squisitamente linguistico: l’’iʿrāb, la reggenza di lā e di illā e del badal. Tali temi saranno spiegati e poi analizzati nel contesto della Risāla.
Nella parte successiva dell’articolo proveremo a fare un confronto tra la moderna grammatica generativa e la grammatica medievale, avvicinando così due sistemi lontani nel tempo, ma vicini nei modi di analisi.
Infine, cercheremo di capire in quale modo lo studio della grammatica medievale possa essere di grande aiuto al discente anche nella comprensione di regole di uso comune
- …
