Efficient Certification Path Discovery for MANET

A Mobile Ad Hoc Network (MANET) is characterized by the lack of any infrastructure, absence of any kind of centralized administration, frequent mobility of nodes, network partitioning, and wireless connections. These properties make traditional wireline security solutions not straightforwardly applicable in MANETs, and of course, constitute the establishment of a Public Key Infrastructure (PKI) in such networks a cumbersome task. After surveying related work, we propose a novel public key management scheme using the well-known web-of-trust or trust graph model. Our scheme is based on a binary tree formation of the network's nodes. The binary tree structure is proved very effective for building certificate chains between communicating nodes that are multihops away and the cumbersome problem of certificate chain discovery is avoided. We compare our scheme with related work and show that it presents several advantages, especially when a fair balancing between security and performance is desirable. Simulations of the proposed scheme under different scenarios demonstrate that it is effective in terms of tree formation, join and leave occurrences, and certificate chain establishment

Probabilistic buckling analysis of stringer-stiffened cylinders

Imperial Users onl

Your face scares me: Effects of Perceptual load and Social Anxiety on processing of threatening and neutral faces

Social Anxiety Disorder is among the most widely studied psychiatric conditions. However, the role of attentional and emotional processes in the maintenance of the condition is still not well-established. This study addressed the impact of individual differences in Social Anxiety, by examining the effects of perceptual load and stimulus valence when processing faces vs objects, here used as distractors, within a letter-search task. In addition to RT and accuracy on the letter search task, heart rate, and skin conductance during the task and participants' self-report emotional evaluation were assessed to help interpret performance effects. Results suggest that distractor stimuli that are either threatening or faces impair performance of high SA participants. Results demonstrate a hypervigilance for threatening faces in SA but indicate that this happens primarily when cognitive resources are available, that is, under low perceptual load

Chest Wall Hydatidosis as the Unique Location of the Disease: Case Report and Review of the Literature

The chest wall is a rare location of secondary hydatidosis, but secondary hydatidosis may occur from the rupture of a lung cyst, from a liver cyst invading the diaphragm into the pleural cavity, following previous thoracic surgery for hydatidosis, or by hematogenous spread. This report describes a case of chest wall hydatidosis, which was the primary disease site in the patient, who had no previous history or current disease (hydatidosis) at other sites. The cyst invaded and partially destroyed the 9th and 10th ribs and the 10th thoracic vertebra, and protruded outside the pleural cavity through the 9th intercostal space. Preoperative albendazole administration for 10 days, surgical resection of the disease through a posterolateral thoracotomy incision, and postoperative albendazole treatment resulted in a cure with no evidence of local recurrence or disease at other sites in four years of follow-up

Sampling versus systematic full lymphatic dissection in surgical treatment of non-small cell lung cancer

The extent of mediastinal lymph node assessment during surgery for non-small cell cancer remains controversial. Different techniques are used, ranging from simple visual inspection of the unopened mediastinum to an extended bilateral lymph node dissection. Furthermore, different terms are used to define these techniques. Sampling is the removal of one or more lymph nodes under the guidance of pre-operative findings. Systematic (full) nodal dissection is the removal of all mediastinal tissue containing the lymph nodes systematically within anatomical landmarks. A Medline search was conducted to identify articles in the English language that addressed the role of mediastinal lymph node resection in the treatment of non-small cell lung cancer. Opinions as to the reasons for favoring full lymphatic dissection include complete resection, improved nodal staging and better local control due to resection of undetected micrometastasis. Arguments against routine full lymphatic dissection are increased morbidity, increase in operative time, and lack of evidence of improved survival. For complete resection of non-small cell lung cancer, many authors recommend a systematic nodal dissection as the standard approach during surgery, and suggest that this provides both adequate nodal staging and guarantees complete resection. Whether extending the lymph node dissection influences survival or recurrence rate is still not known. There are valid arguments in favor in terms not only of an improved local control but also of an improved long-term survival. However, the impact of lymph node dissection on long-term survival should be further assessed by large-scale multicenter randomized trials

Efficient Certification Path Discovery for MANET

A Mobile Ad Hoc Network (MANET) is characterized by the lack of any infrastructure, absence of any kind of centralized administration, frequent mobility of nodes, network partitioning, and wireless connections. These properties make traditional wireline security solutions not straightforwardly applicable in MANETs, and of course, constitute the establishment of a Public Key Infrastructure (PKI) in such networks a cumbersome task. After surveying related work, we propose a novel public key management scheme using the well-known web-of-trust or trust graph model. Our scheme is based on a binary tree formation of the network's nodes. The binary tree structure is proved very effective for building certificate chains between communicating nodes that are multihops away and the cumbersome problem of certificate chain discovery is avoided. We compare our scheme with related work and show that it presents several advantages, especially when a fair balancing between security and performance is desirable. Simulations of the proposed scheme under different scenarios demonstrate that it is effective in terms of tree formation, join and leave occurrences, and certificate chain establishment.</p

Bilious pericardial effusion at initial presentation in a patient with lung cancer

Abstract Background Cardiac tamponade as the initial manifestation of metastatic cancer is a rare clinical entity. Furthermore, a thoraco-biliary fistula is another rare complication of echinococcosis due to rupture of hydatid cysts located at the upper surface of the liver to the pleural or pericardial cavity. We report a case of non-small cell lung cancer with a coexisting hepatic hydatid cyst presenting as a bilious pericardial effusion. Case report A 66-year-old patient presented with cardiac tamponade of unknown origin. Chest CT-scan demonstrated a left central lung tumor, a smaller peripheral one, bilateral pleural effusions and a hydatid cyst on the dome of the liver in close contact to the diaphragm and pericardium. Pericardiotomy with drainage was performed, followed by bleomycin pleurodesis. The possible mechanism for the bilious pericardial effusion might be the presence of a pericardio-biliary fistula created by the hepatic hydatid cyst. Conclusions This is the first case of a bilious pericardial effusion at initial presentation in a patient with lung cancer with coexisting hepatic hydatid cyst.</p