Characterization of Acoustic Resonance in a High Pressure Sodium Lamp

With the last decades, the high pressure sodium (HPS) lamp has been supplied in high frequency in order to increase the efficacy of the lamp/ballast system. However, at some given frequencies, standing acoustic waves, namely acoustic resonance (AR), might develop in the burner and cause lamp luminous fluctuation, extinction and destruction in the most serious case. As we seek for a control method to detect and avoid the lamp AR some main characteristics of the acoustic resonances in a 150W HPS lamp are presented in this paper,. The first one is the characteristic of the lamp AR threshold power, the second one is the differences between forward and backward frequency scanning effects during lamp open loop operation. Thirdly, lamp AR behaviour in closed loop operation with an LCC half bridge inverter will be presented and leads to a new point of view and a change in the choice of the AR detection method. These characteristics allow us to further understand the AR and to better control the lamp

Ofcom’s Plurality Framework: A step in the right direction, but still unfinished work

Following the recent publication by Ofcom of its measurement framework for media plurality, LSE Research Officer Sharif Labo argues that although there are significant gaps in the framework, it offers a solid foundation to measure plurality in a fast-changing media environment. The UK Parliament, in consultation with Ofcom, must now use the opportunity of the first baseline assessment to set out ‘bright line’ guidance on what constitutes sufficient plurality, as well as to explore steps to gain more insights into how technology is impacting news consumption. Damian Tambini and Sharif Labo’s policy brief, Monitoring Media Plurality after Convergence, can be read here

Digital intermediaries in the UK: implications for newsplurality

Digital intermediaries such as Google and Facebook are seen as the new power brokers in online news, controlling access to consumers and even suppressing or targeting messages. After reviewing literature that raised this concern, this paper examines empirical evidence for the claim that intermediaries pose a threat to news plurality. We introduce a three-stage analytical framework for measuring the role of intermediaries within the current policy framework for media plurality: (i) analysis of share of online in news consumption (ii) role of intermediaries (iii) degree of bias versus neutrality of intermediary control of news. Through secondary analysis of UK industry data on referrals of online news traffic, we find that an increasing proportion of news is delivered online, and a significant proportion of online news is accessed via intermediaries. However, we find that not all news that is filtered through intermediary services is subject to the same shaping and editorial forces, in part because user agency is also an important factor. The role of intermediaries in news distribution is thus complex; market share and market concentration does not translate automatically into influence due to the complex interplay between user agency and the editorial influence of intermediaries

Passenger Name Records and data protection issues: busting some myths

The Leveson Inquiry debated media plurality in the UK, and the implication of concentrated media power for democracy, but did not make detailed recommendations for policy change. Since then, Parliament and also Government have consulted. Now the regulator Ofcom has been asked to come up with a new framework for measuring media plurality and is consulting on this until 20 May. Sharif Labo and Damian Tambini argue that this new framework must be expanded to consider the new risks that arise from the role of internet intermediaries

Ofcom consultation – implications for Google and Facebook?

The Leveson Inquiry debated media plurality in the UK, and the implication of concentrated media power for democracy, but did not make detailed recommendations for policy change. Since then, Parliament and also Government have consulted. Now the regulator Ofcom has been asked to come up with a new framework for measuring media plurality and is consulting on this until 20 May. Sharif Labo and Damian Tambini argue that this new framework must be expanded to consider the new risks that arise from the role of internet intermediaries

Parasitoses digestives de l'enfant scolarisé en République du Niger

Des enquêtes coprologiques réalisées en milieu scolaire dans plusieurs zones de l'ouest de la République du Niger ont fourni les résultats suivants. En ce qui concerne les protozoaires, la prévalence de l'amibiase-infestation est forte dans toutes les régions étudiées, la giardase est plus fréquente dans les régions sèches. Pour les helminthes, HYMENOLEPIS NANA se rencontre partout, la prévalence de l'ankylostomiase va en décroissant du sud au nord et l'aire de répartition de SCHISTOSOMA MANSONI est restreinte à l'extrême sud du pays. Les autres helminthiases sont peu fréquentes (Résumé d'auteur

Acoustic Resonance Characterization and Numerical Model Including Acoustic Streaming in an HPS Lamp

This paper presents a numerical model of High Pressure Sodium (HPS) lamps including the acoustic streaming. The model is implemented in COMSOL and based on the finite elements method using a 2D axi-symmetric geometry. Moreover, a revision concerning AR experimental characterizations of HPS lamps will also be provided. The results presented in this paper will contribute to the understanding of AR phenomena and help in the electronic ballast design methods for AR avoidance

Age of Infection with Kaposi Sarcoma-Associated Herpesvirus and Subsequent Antibody Values Among Children in Uganda.

We investigated associations between Kaposi sarcoma-associated herpesvirus (KSHV) seroconversion age and KSHV antibody values in Ugandan children. Every annual delay in KSHV seroconversion age was associated with a reduction of 19% (P < 0.0001) in K8.1 and 27% (P < 0.0001) in ORF73 antibody values at 6 years of age. Early infection may be an important risk factor for KSHV pathogenesis and viral shedding in saliva, leading to transmission

The Rank of the Odd Normal Out

Say we have a collection of independent random variables $X_0, ... , X_n$, where $X_0 \sim \mathcal{N}(\mu_0, \sigma_0^2)$, but $X_i \sim \mathcal{N}(\mu, \sigma^2)$, for $1 \leq i \leq n$. We characterize the distribution of $R_0 := 1 + \sum_{i=1}^{n} \mathbf{1}\{X_i \leq X_0\}$, the rank of the random variable whose distribution potentially differs from that of the others -- the odd normal out. We show that $R_0 - 1$ is approximately beta-binomial, an approximation that becomes equality as $\sigma/\sigma_0$ or $(\mu-\mu_0)/\sigma_0$ become large or small. The intra-class correlation of the approximating beta-binomial depends on $\Pr(X_1 \leq X_0)$ and $\Pr(X_1 \leq X_0, X_2 \leq X_0)$. Our approach relies on the conjugacy of the beta distribution for the binomial: $\Phi((X_0-\mu)/\sigma)$ is approximately $\mathrm{Beta}(\alpha(\sigma/\sigma_0, (\mu-\mu_0)/\sigma_0), \beta(\sigma/\sigma_0, (\mu-\mu_0)/\sigma_0))$ for functions $\alpha, \beta > 0$. We study the distributions of the in-normal ranks. Throughout, simulations corroborate the formulae we derive.Comment: 81 pages, 14 figure