The power of A/B testing under interference

In this paper, we address the fundamental statistical question: how can you assess the power of an A/B test when the units in the study are exposed to interference? This question is germane to many scientific and industrial practitioners that rely on A/B testing in environments where control over interference is limited. We begin by proving that interference has a measurable effect on its sensitivity, or power. We quantify the power of an A/B test of equality of means as a function of the number of exposed individuals under any interference mechanism. We further derive a central limit theorem for the number of exposed individuals under a simple Bernoulli switching interference mechanism. Based on these results, we develop a strategy to estimate the power of an A/B test when actors experience interference according to an observed network model. We demonstrate how to leverage this theory to estimate the power of an A/B test on units sharing any network relationship, and highlight the utility of our method on two applications - a Facebook friendship network as well as a large Twitter follower network. These results yield, for the first time, the capacity to understand how to design an A/B test to detect, with a specified confidence, a fixed measurable treatment effect when the A/B test is conducted under interference driven by networks.Comment: 14 page

Strategi Dinas Kehutanan dan Perkebunan Kabupaten Kepulauan Meranti dalam Mengkomunikasikan Gerakan Rehabilitasi Hutan dan Lah Mangrove

Damaged forests can cause disasters such as floods and landslides. This also happens in one region of Indonesia, Meranti Islands district have also suffered damage from natural disasters or human activity itself, forest destruction worst that happened in the district of Meranti namely mangrove forests, where the destruction of mangrove forests could impact beach abrasion. The purpose of this study was to determine how the Department of Forestry and Plantation Meranti Islands regency in running communication strategy in the program implementation mangrove forest and land rehabilitation.In this study the authors used a qualitative research method with a phenomenological approach. Data collection techniques are grouped through observation, interviews and documentation. The informant in this research were six people who were taken by purposive sampling techniques, ie 5 civil servants and 1 community. Interactive data analysis type the researchers use to describe the results of research into techniques for data analysis and data validity checking researcher using triangulation techniques.The results in which the communication strategy is executed in accordance with the steps of planning strategies, ie; to identify their communication, communication media selection and assessment destination of the message. From interviews and observations of researchers got field indicates that the Department of Forestry and Plantation Regency Meranti has been doing business in recognizing the target of communication, working with some of the media, both print and electronic media as well as services to create and examine the messages to be conveyed to the public related program mangrove forest and land rehabilitation

Data

Chemistry (gas chromatography results): relative amounts of cuticular compounds extracted from bumblebee nest wax and from cuticle surfaces of sterile and fertile workers and egg-laying queens; Results from group experiments: observed behaviour (neutral, aggressive, defensive) and ovarian development (percent

Macrolides and Alcohols as Scent Gland Constituents of the Madagascan Frog <i>Mantidactylus femoralis</i> and Their Intraspecific Diversity

Acoustic and, to a lesser degree, visual signals are the predominant means of signaling in frogs. Nevertheless, certain lineages such as the mantelline frogs from Madagascar use the chemical communication channel as well. Males possess femoral glands on the hind legs, which recently have been shown to contain volatile compounds used in communication as pheromones. Many mantelline species occur in sympatry, and so far species recognition is regarded to occur mainly by acoustic signals. The analysis of the gland constituents of <i>Mantidactylus femoralis</i> by GC/MS revealed the presence of volatile macrolides and secondary alcohols. The new natural products mantidactolides A (<b>4</b>) and B (<b>6</b>), as well as several methyl carbinols, were identified, and their structures were confirmed by synthesis. The analysis of individuals from different locations of Madagascar revealed the presence of two groups characterized by specific patterns of compounds. While one group contained the alcohols and mantidactolide B, the other showed specific presence of the macrolides phoracantholide I (<b>1</b>) and mantidactolide A (<b>4</b>). Genetic analysis of some individuals showed no congruence between genetic relatedness and gland constituents. Several other individuals from related species had different gland compositions. This suggests that a basic set of biosynthetic machinery might be available to a broader group of related species

Agonist-stimulated ³⁵S-GTPγS binding.

<p>Stimulation of [³⁵S]GTPγS binding by SS-14, Octreotide, Pasireotide and Somatoprim in the concentration range of 10⁻¹² to 10⁻⁶ M. Membranes wer prepared from HEK293 cells stably expressing either the human sst₂, sst₅ and sst₅-sst_2ACT or the rat sst₃-sst_2ACT receptor. Values represent means of triplicate determinations. SE values were smaller than 15%. Three replicate experiments gave similar results.</p

Hierarchical Organization of Multi-Site Phosphorylation at the CXCR4 C Terminus

<div><p>The chemokine receptor CXCR4 regulates cell migration during ontogenesis and disease states including cancer and inflammation. Upon stimulation by the endogenous ligand CXCL12, CXCR4 becomes phosphorylated at multiple sites in its C-terminal domain. Mutations in the CXCR4 gene affecting C-terminal phosphorylation sites are a hallmark of WHIM syndrome, a genetic disorder characterized by a gain-of-CXCR4-function. To better understand how multi-site phosphorylation of CXCR4 is organized and how perturbed phosphorylation might affect CXCR4 function, we developed novel phosphosite-specific CXCR4 antibodies and studied the differential regulation and interaction of three C-terminal phosphorylation sites in human embryonic kidney cells (HEK293). CXCL12 promoted a robust phosphorylation at S346/347 which preceded phosphorylation at S324/325 and S338/339. After CXCL12 washout, the phosphosites S338/339 and S324/325 were rapidly dephosphorylated whereas phosphorylation at S346/347 was long-lasting. CXCL12-induced phosphorylation at S346/347 was staurosporine-insensitive and mediated by GRK2/3. WHIM syndrome-associated CXCR4 truncation mutants lacking the S346/347 phosphosite and the recently identified E343K WHIM mutant displayed strongly impaired phosphorylation at S324/325 and S338/339 as well as reduced CXCL12-induced receptor internalization. Relevance of the S346-S348 site was confirmed by a S346-348A mutant showing strongly impaired CXCL12-promoted phosphorylation at S324/325 and S338/339, defective internalization, gain of calcium mobilization, and reduced desensitization. Thus, the triple serine motif S346-S348 contains a major initial CXCR4 phosphorylation site and is required for efficient subsequent multi-site phosphorylation and receptor regulation. Hierarchical organization of CXCR4 phosphorylation explains why small deletions at the extreme CXCR4 C terminus typically associated with WHIM syndrome severely alter CXCR4 function.</p></div

Figure 2

<p><b>Sequential phosphorylation at CXCR4 C-terminal sites. </b><b>A–F</b>, Stably CXCR4-transfected HEK293 cells were stimulated with 20 nM CXCL12 for 0, 2, 5, and 15 min. Aliquots of the lysates were detected in four immunoblots using the indicated antibodies. Blots were stripped and reprobed with anti-HA and anti-transferrin receptor (TFR) to control for equal loading. <b>A</b>,<b>B</b>, CXCL12 induces a rapid loss of the anti-S341-S352 signal and a concomitant immediate increase of the anti-pS346/347 signal. <b>C</b>, Maximal S338/339 phosphorylation requires 15 min CXCL12 stimulation. <b>D</b>, Demonstration of rapid CXCL12-promoted S324/325 phosphorylation. <b>E</b>–<b>I</b>, The signal ratio versus anti-HA was determined for the four anti-CXCR4 antibodies using densitometry. The ratio was set as 100% at 0 min for anti-S341-S352 (G) and at 15 min for the phospho-selective antibodies (G–I). Data represent mean+SEM from 4–5 independent experiments. <b>G</b>, Note complementarity of the anti-S341-S352 and anti-pS346/347 time courses. <b>H</b>,<b>I</b>, Phosphorylation occurs faster at S346/347 than at S338/339 and S324/325. *: p<0.05; 1way ANOVA and Bonferronís multiple comparison post-test for selected groups.</p

Agonist-selective phosphorylation of the human sst₅ and sst₅-sst₂CT chimera.

<p>(<i>A</i>,<i>Top panel</i>) Schematic representation of the sst₅-sst₂CT receptor indicating the phosphate acceptor sites S341/343, T353/354 and T356/359 within the carboxyl-terminal tail. (<i>A</i>, <i>Bottom</i>) HEK293 cells stably expressing the sst₅-sst_2ACT receptor were either not exposed or exposed for 5 min to SS-14, octreotide, pasireotide or somatoprim in concentrations ranging from 10⁻¹² to 10⁻⁵ M. The levels of phosphorylated sst₅-sst_2ACT receptors were then determined using the phosphosite-specific antibodies anti-pS341/pS343 {3157}, anti-pT353/pT354 {0521} and anti-pT356/pT359 {0522}. (<i>B</i>,<i>Top panel</i>) Schematic representation of the human sst₅ receptor indicating the phosphate acceptor site T333 within its carboxyl-terminal tail. (<i>B</i>, <i>Bottom</i>) HEK293 cells stably expressing the human sst₅ receptors were either not exposed or exposed for 5 min to SS-14, octreotide, pasireotide or somatoprim in concentrations ranging from 10⁻¹² to 10⁻⁵ M. The levels of phosphorylated sst₅ receptors were then determined using the phosphosite-specific antibodies anti-pT333 {3567}. Western blots shown are representative of three to five independent experiments for each condition. The positions of the molecular mass markers are indicated on the left (in kDa).</p

Additional file 3 of Ontological interpretation of biomedical database content

SUBC representation example. (OWL 69.2 kb

Additional file 5 of Ontological interpretation of biomedical database content

DISP representation example. (OWL 14.7 kb