An Innovative Signature Detection System for Polymorphic and Monomorphic Internet Worms Detection and Containment

Most current anti-worm systems and intrusion-detection systems use signature-based technology instead of anomaly-based technology. Signature-based technology can only detect known attacks with identified signatures. Existing anti-worm systems cannot detect unknown Internet scanning worms automatically because these systems do not depend upon worm behaviour but upon the worm’s signature. Most detection algorithms used in current detection systems target only monomorphic worm payloads and offer no defence against polymorphic worms, which changes the payload dynamically. Anomaly detection systems can detect unknown worms but usually suffer from a high false alarm rate. Detecting unknown worms is challenging, and the worm defence must be automated because worms spread quickly and can flood the Internet in a short time. This research proposes an accurate, robust and fast technique to detect and contain Internet worms (monomorphic and polymorphic). The detection technique uses specific failure connection statuses on specific protocols such as UDP, TCP, ICMP, TCP slow scanning and stealth scanning as characteristics of the worms. Whereas the containment utilizes flags and labels of the segment header and the source and destination ports to generate the traffic signature of the worms. Experiments using eight different worms (monomorphic and polymorphic) in a testbed environment were conducted to verify the performance of the proposed technique. The experiment results showed that the proposed technique could detect stealth scanning up to 30 times faster than the technique proposed by another researcher and had no false-positive alarms for all scanning detection cases. The experiments showed the proposed technique was capable of containing the worm because of the traffic signature’s uniqueness

The fidelity of synaptonemal complex assembly is regulated by a signaling mechanism that controls early meiotic progression

© 2014 Elsevier Inc.Proper chromosome segregation during meiosis requires the assembly of the synaptonemal complex (SC) between homologous chromosomes. However, the SC structure itself is indifferent to homology, andpoorly understood mechanisms that depend on conserved HORMA-domain proteins prevent ectopic SC assembly. Although HORMA-domain proteins are thought to regulate SC assembly as intrinsic components of meiotic chromosomes, here we uncover a key role for nuclear soluble HORMA-domain protein HTP-1 in the quality control of SC assembly. We show that a mutant form of HTP-1 impaired in chromosome loading provides functionality of an HTP-1-dependent checkpoint that delays exit from homology search-competent stages until all homolog pairs are linked by the SC. Bypassing of this regulatory mechanism results in premature meiotic progression and licensing of homology-independent SC assembly. These findings identify nuclear soluble HTP-1 as a regulator of early meiotic progression, suggesting parallels with the mode of action of Mad2 in the spindle assembly checkpoint

Especies invasoras y conservación

El medio marino está en peligro: la explotación excesiva de sus recursos, la destrucción del hábitat, la contaminación y el cambio climático están impulsando la pérdida de biodiversidad (IUCN Amenaza marina). Las invasiones biológicas o bioinvasiones son consideradas actualmente como una de las más graves amenazas a la biodiversidad mundial (IUCN, 2000) y llega a esta situación a través de la exclusión competitiva, la alteración del hábitat, la depredación, etc. (Schwindt, et al., 2009). Las especies invasoras son capaces de modificar el entorno en el que se introducen causando cambios drásticos en la flora y fauna nativa, tendiendo hacia la homogenización de la biodiversidad mundial (Carlton, 1989). Asimismo, a los organismos que, por su propia presencia, modifican las condiciones abióticas y bióticas de su entorno se los llaman ingenieros de ecosistemas (Jones et al., 1994). Las especies invasoras pueden actuar como “ingenieros de ecosistemas”; los cambios ambientales que provocan pueden tener un fuerte efectos sobre la estructura de la comunidad como ya fue descrito para la Cuenca del Plata, tanto en su componente abiótico como biótico (Darrigran y Damborenea, 2011).Facultad de Ciencias Naturales y Muse

A New Web Search Engine with Learning Hierarchy

Most of the existing web search engines (such as Google and Bing) are in the form of keyword-based search. Typically, after the user issues a query with the keywords, the search engine will return a flat list of results. When the query issued by the user is related to a topic, only the keyword matching may not accurately retrieve the whole set of webpages in that topic. On the other hand, there exists another type of search system, particularly in e-Commerce web- sites, where the user can search in the categories of different faceted hierarchies (e.g., product types and price ranges). Is it possible to integrate the two types of search systems and build a web search engine with a topic hierarchy? The main diffculty is how to classify the vast number of webpages on the Internet into the topic hierarchy. In this thesis, we will leverage machine learning techniques to automatically classify webpages into the categories in our hierarchy, and then utilize the classification results to build the new search engine SEE. The experimental results demonstrate that SEE can achieve better search results than the traditional keyword-based search engine in most of the queries, particularly when the query is related to a topic. We also conduct a small-scale usability study which further verifies that SEE is a promising search engine. To further improve SEE, we also propose a new active learning framework with several novel strategies for hierarchical classification

Virtual Hood: Exploring The Hip-hop Culture Experience In A British Online Community.

In this fast-paced, globalized world, certain online sites represent a hybrid personal-public sphere\u27where like-minded people commune regardless of physical distance, time difference, or lack of synchronicity. Sites that feature chat rooms and forums can offer a deep-rooted sense of community and facilitate the forging of relationships and cultivation of ideologies. This dissertation investigates whether this trend is relevant to web sites concerning hip-hop. This genre is arguably one of the most pervasive and influential global cultural forms, yet it is markedly different from most other forms of globalized culture because it emerged within and is still embedded in a distinct subculture. The notion that the Internet could become a bastion for hip-hop fans is quite paradoxical: hip hop is a cultural form so deeply rooted in the sense of place and so invested in its relationship to spatiality that it could potentially pose a particular challenge to the notion of virtual communities. This research examines the virtual hip-hop experience in the UK in order to assess whether this music and the culture that surrounds it have been adopted in their original American form or whether they have been adapted to make them more relevant to their new locale. In particular, the study probes how the ideology, values, behaviors and attitudes that bestride American hip-hop are represented, consumed, and reproduced on the mediated world of web sites

High-resolution single-worm transcriptomics and the function of oscillating genes in mouth-form development in Pristionchus pacificus

Development is largely under the control of genes. Specific spatiotemporal gene expression can modify the development and the final phenotype of an organism. To obtain a high-resolution catalog of the developmental transcriptome in Pristionchus pacificus, I developed and implemented a single worm transcriptomic approach for the nematode model organism P. pacificus, and performed temporal transcriptome analysis over the entire postembryonic development with 38 time points. I focused on investigating oscillating gene expression patterns and found that i) nearly 3000 oscillating genes are periodically expressed during postembryonic development, ii) there is an overrepresentation of ancient gene classes among oscillatory genes, and iii) the developmental switch gene eud-1 mediates numerous oscillatory genes including collagens, indicating the potential roles of these oscillating collagens in regulating mouth-form plasticity. Mouth-form dimorphism in P. pacificus provides an ideal example to study the mechanisms of phenotype plasticity. Many previous studies focused on the regulation of mouth-form development and identified environmental influences, developmental switches, the gene regulatory network involved in mouth-form plasticity, and the associated evolutionary processes. However, the molecular and structural basis of the teeth in P. pacificus remains poorly understood. To address this fundamental question, I used two complementary approaches. First, I performed a large-scale genetic screen and obtained six mutants displaying morphological changes in both stomatal structures and body shape. Using whole genome sequencing and genome editing (CRISPR/Cas9 system) technologies, I identified Ppa-dpy-6, which encodes a mucin-type protein, as the first structural component of the nematode stoma involved in the specification of the cheilostom and cuticle. Second, I investigated the function of two chitin synthase genes (chs) in P. pacificus. Phylogenetic analysis revealed that two chitin synthase genes are highly conserved across nematodes. Mutations in the C- terminus of chs-2 in P. pacificus result in a viable but teethless phenotype. Moreover, animals with this teethless phenotype were observed after injection of the chitin-synthase inhibitor Nikkomycin Z. These results suggest that the conserved Ppa-chs-2 is essential for P. pacificus teeth formation. In addition, such teethless mutants can feed on various bacterial food sources, yet they are incapable of predation