Liesegang patterns: Effect of dissociation of the invading electrolyte

The effect of dissociation of the invading electrolyte on the formation of Liesegang bands is investigated. We find, using organic compounds with known dissociation constants, that the spacing coefficient, 1+p, that characterizes the position of the n-th band as x_n ~ (1+p)^n, decreases with increasing dissociation constant, K_d. Theoretical arguments are developed to explain these experimental findings and to calculate explicitly the K_d dependence of 1+p.Comment: RevTex, 8 pages, 3 eps figure

Throughput and energy efficiency in IEEE 802.11 WLANs: friends or foes?

Proceedings of: 6th International ICST Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness, QShine 2009 and 3rd International Workshop on Advanced Architectures and Algorithms for Internet Delivery and Applications, AAA-IDEA 2009, Las Palmas, Gran Canaria, November 23-25, 2009Understanding and optimizing the energy consumption of wireless devices is critical to maximize network lifetime and to provide guidelines for the design of new protocols and interfaces. In this work we first provide an accurate analysis of the energy performance of an IEEE 802.11 WLAN, and then we derive the configuration to maximize it. We also analyze the impact of the energy configuration of the device on the throughput performance, and discuss in which circumstances throughput and energy efficiency can be both maximized and where they constitute different challenges.European Community's Seventh Framework ProgramPublicad

Semantic-based policy engineering for autonomic systems

This paper presents some important directions in the use of ontology-based semantics in achieving the vision of Autonomic Communications. We examine the requirements of Autonomic Communication with a focus on the demanding needs of ubiquitous computing environments, with an emphasis on the requirements shared with Autonomic Computing. We observe that ontologies provide a strong mechanism for addressing the heterogeneity in user task requirements, managed resources, services and context. We then present two complimentary approaches that exploit ontology-based knowledge in support of autonomic communications: service-oriented models for policy engineering and dynamic semantic queries using content-based networks. The paper concludes with a discussion of the major research challenges such approaches raise

Romantic jealousy and relationship satisfaction: the costs of rumination

The experience of romantic jealousy and its influence on relationship outcomes is unclear. Romantic jealousy is often associated with damaging effects; on the other hand, jealousy is linked to positive relationship outcomes such as increased commitment. In this study, we aimed to address inconsistencies in previous research by proposing rumination as a mediator between romantic jealousy (cognitive jealousy and surveillance behaviors) and relationship dissatisfaction. We also aimed to extend our understanding of behavioral responses to jealousy, and in particular, partner surveillance and its link to relational dissatisfaction by proposing a research question. Overall, there were two paths to relationship dissatisfaction: Cognitive jealousy and surveillance behaviors were associated with relationship dissatisfaction via rumination, and cognitive jealousy was also directly associated with relationship dissatisfaction. Interestingly, surveillance behaviors were directly associated with relationship satisfaction. From these results, rumination is highlighted as a factor in explaining the link between romantic jealousy and relationship dissatisfaction. Clinical implications are discussed

Leadership and decision-making practices in public versus private universities in Pakistan

The goal of this study is to examine differences in leadership and decision-making practices in public and private universities in Pakistan, with a focus on transformational leadership (TL) and participative decision-making (PDM). We conducted semi-structured interviews with 46 deans and heads of department from two public and two private universities in Pakistan. Our findings indicate that leadership and decision-making practices are different in public and private universities. While differences were observed in all six types of TL-behaviour, the following three approaches emerged to be crucial in both public and private universities: (1) articulating a vision, (2) fostering the acceptance of group goals, and (3) high-performance expectations. In terms of PDM, deans and heads of department in public and private universities adopt a collaborative approach. However, on a practical level this approach is limited to teacher- and student-related matters. Overall, our findings suggest that the leadership and decision-making practices in Pakistani public and private universities are transformational and participative in nature

Relief in everyday life

Despite being implicated in a wide range of psychological and behavioral phenomena, relief remains poorly understood from the perspective of psychological science. What complicates the study of relief is that people seem to use the term to describe an emotion that occurs in two distinct situations: when an unpleasant episode is over, or upon realizing that an outcome could have been worse. This study constitutes a detailed empirical investigation of people’s reports of everyday episodes of relief. A set of four studies collected a large corpus (N = 1835) of first-person reports of real-life episodes of relief and examined people’s judgments about the antecedents of relief, its relation to counterfactual thoughts, and its subsequent effects on decision making. Some participants described relief experiences that had either purely temporal or purely counterfactual precursors. Nevertheless, the findings indicated that the prototypical instance of relief appears to be one in which both these elements are present. The results also suggest that, although relief is frequently experienced in situations in which people are not responsible for the relief-inducing event, nevertheless they typically report that the experience had a positive impact on subsequent decision making

An international, phase III randomized trial in patients with mucinous epithelial ovarian cancer (mEOC/GOG 0241) with long-term follow-up: and experience of conducting a clinical trial in a rare gynecological tumor

Objectives We evaluated four different treatment regimens for advanced-stage mucinous epithelial ovarian cancer. Methods We conducted a multicenter randomized factorial trial (UK and US). Patients were diagnosed with primary mEOC: FIGO stage II–IV or recurrence after stage I disease. Treatment arms were paclitaxel-carboplatin, oxaliplatin-capecitabine, paclitaxel-carboplatin-bevacizumab, or oxaliplatin-capecitabine-bevacizumab. Chemotherapy was given 3-weekly for 6 cycles, and bevacizumab (3-weekly) was continued as maintenance (for 12 cycles). Endpoints included overall-survival (OS), progression-free survival (PFS), toxicity and quality of life (QoL). Results The trial stopped after 50 patients were recruited due to slow accrual. Median follow-up was 59 months. OS hazard ratios (HR) for the two main comparisons were: 0.78 (p = 0.48) for Oxal-Cape vs. Pac-Carbo (each with/without bevacizumab), and 1.04 (p = 0.92) for bevacizumab vs. no bevacizumab. Corresponding PFS HRs were: 0.84 and 0.80. Retrospective central pathology review revealed only 45% (18/40) cases with available material had confirmed primary mEOC. Among these, OS HR for Oxal-Cape vs. Pac-Carbo was 0.36 (p = 0.14); PFS HR = 0.62 (p = 0.40). Grade 3–4 toxicity was seen in 61% Pac-Carbo, 61% Oxal-Cape, 54% Pac-Carbo-Bev, and 85% Oxal-Cape-Bev. QoL was similar between the four arms. Conclusion mEOC/GOG0241 represents an example of a randomized rare tumor trial. Logistical challenges led to early termination, including difficulties in local histopathological diagnosis and accessing drugs outside their labelled indication. There was misalignment between central funders who support clinical trials in rare cancers and the deprioritisation of such work by those managing and funding research at a local level. Rare cancer trials should include centralised pathology review before treatment. Clinical trial registry number: ISRCTN83438782