Assessing statistical significance of periodogram peaks

The least-squares (or Lomb-Scargle) periodogram is a powerful tool which is used routinely in many branches of astronomy to search for periodicities in observational data. The problem of assessing statistical significance of candidate periodicities for different periodograms is considered. Based on results in extreme value theory, improved analytic estimations of false alarm probabilities are given. They include an upper limit to the false alarm probability (or a lower limit to the significance). These estimations are tested numerically in order to establish regions of their practical applicability.Comment: 7 pages, 6 figures, 1 table; To be published in MNRA

Escalation of error catastrophe for enzymatic self-replicators

It is a long-standing question in origin-of-life research whether the information content of replicating molecules can be maintained in the presence of replication errors. Extending standard quasispecies models of non-enzymatic replication, we analyze highly specific enzymatic self-replication mediated through an otherwise neutral recognition region, which leads to frequency-dependent replication rates. We find a significant reduction of the maximally tolerable error rate, because the replication rate of the fittest molecules decreases with the fraction of functional enzymes. Our analysis is extended to hypercyclic couplings as an example for catalytic networks.Comment: 6 pages, 4 figures; accepted at Europhys. Let

What does not happen: quantifying embodied engagement using NIMI and self-adaptors

Previous research into the quantification of embodied intellectual and emotional engagement using non-verbal movement parameters has not yielded consistent results across different studies. Our research introduces NIMI (Non-Instrumental Movement Inhibition) as an alternative parameter. We propose that the absence of certain types of possible movements can be a more holistic proxy for cognitive engagement with media (in seated persons) than searching for the presence of other movements. Rather than analyzing total movement as an indicator of engagement, our research team distinguishes between instrumental movements (i.e. physical movement serving a direct purpose in the given situation) and non-instrumental movements, and investigates them in the context of the narrative rhythm of the stimulus. We demonstrate that NIMI occurs by showing viewers’ movement levels entrained (i.e. synchronised) to the repeating narrative rhythm of a timed computer-presented quiz. Finally, we discuss the role of objective metrics of engagement in future context-aware analysis of human behaviour in audience research, interactive media and responsive system and interface design

A time series feature of variability to detect two types of boredom from motion capture of the head and shoulders

Boredom and disengagement metrics are crucial to the correctly timed implementation of adaptive interventions in interactive systems. psychological research suggests that boredom (which other HCI teams have been able to partially quantify with pressure-sensing chair mats) is actually a composite: lethargy and restlessness. Here we present an innovative approach to the measurement and recognition of these two kinds of boredom, based on motion capture and video analysis of changes in head and shoulder positions. Discrete, three-minute, computer-presented stimuli (games, quizzes, films and music) covering a spectrum from engaging to boring/disengaging were used to elicit changes in cognitive/emotional states in seated, healthy volunteers. Interaction with the stimuli occurred with a handheld trackball instead of a mouse, so movements were assumed to be non-instrumental. Our results include a feature (standard deviation of windowed ranges) that may be more specific to boredom than mean speed of head movement, and that could be implemented in computer vision algorithms for disengagement detection

Making Cornish-Fisher fit for risk measurement

Peer reviewedPostprintPostprintOthe

Penetration depth study of LaOs4_4Sb12_{12}: Multiband s-wave superconductivity

We measured the magnetic penetration depth $\lambda(T)$ in single crystals of LaOs$_{4}$Sb$_{12}$ ($T_c$=0.74 K) down to 85 mK using a tunnel diode oscillator technique. The observed low-temperature exponential dependence indicates a s-wave gap. Fitting the low temperature data to BCS s-wave expression gives the zero temperature gap value $\Delta (0)= (1.34 \pm 0.07) k_B T_c$ which is significantly smaller than the BCS value of 1.76$k_B T_c$. In addition, the normalized superfluid density $\rho(T)$ shows an unusually long suppression near $T_c$, and are best fit by a two-band s-wave model.Comment: 5 pages, 2 figure

Prognostic value of serum levels of immunoglobulins (IgG, IgA, IgM and IgE) in breast cancer: a preliminary study.

One hundred and sixty women admitted for breast tumour biopsy to the King's College Hospital group have been followed sequentially for 2 years. Sixty-nine women had early operable breast cancer and 91 had benign breast disease. All these women had serum immunoglobulin IgG, IgA, IgM and IgE levels measured preoperatively and postoperatively at 3 months, 1 year and 2 years. No differences were found in any of the serum immunoglobulin levels between the two groups at any time. There was, however, a positive correlation between the extent of metastatic breast cancer and the serum level of various immunoglobulins, particularly IgA. There was no evidence that routine postoperative radiotherapy influenced the levels of serum immunoglobulins. The findings suggest a secondary defence reaction against increasing tumour load, and do not support the theory of an early immune defect in immunoglobulin metabolism which could play a part in the pathogenesis of breast cancer. Although there is no diagnostic value in measuring the levels of serum immunoglobulins in patients with breast tumours, there may be some value in following the levels in cancer patients, as a guide to subclinical spread of the disease

Formulasi Sampo Antiketombe dari Ekstrak Kubis (Brassica Oleracea Var. Capitata L.) Kombinasi Ekstrak Daun Pandan Wangi (Pandanus Amaryllifolius Roxb)

Sampo ekstrak kubis kombinasi daun pandan wangi adalah sediaan kosmetik yang dibuat dari bahan dasar ekstrak kubis dan daun pandan wangi serta penambahan bahan lain yang dapat digunakan pada kulit kepala tanpa menimbulkan iritas. Ekstrak kubis dan daun pandan wangi memiliki senyawa yang berkhasiat menghambat pertumbuhan ketombe pada kulit kepala , penelitian ini bertujuan untuk membuat sediaan sampo antiketombe dari ekstrak kubis kombinasi daun pandan wangi yang dapat memenuhi uji evaluasi fisik sediaan. Penelitian ini dilakukan secara eksperimental dengan beberapa evaluasi fisik sediaan diantaranya yaitu uji organoleptik, berdasarkan warna, bentuk dan aroma sediaan, uji pH, uji tinggi busa, uji homogenitas, dan uji viskositas. Hasil penelitian menunjukan formula sampo antiketombe ekstrak kubis dan daun pandan wangi hasilnya menunjukka bahwa uji evaluasi fisik sediaan sampo antiketombe ekstrak kubis kombinasi daun panan wangi memenuhi syarat secara fisik, pada uji organoleptik warna yang dihasilkan dari ketiga formula yaitu formula A, formula B dan formula C berwarna hijau gelap disebabkan oleh zat aktif yang digunakan yaitu daun pandan wangi, aroma yang dihasilkan adalah aroma dari penambahan pewangi yang digunakan dalam sediaan, pewangi yang digunakan yaitu minyak mawar serta bentuk dari sediaan yaitu kental. Pada uji pH ketiga formulasi telah memenuhi syarat mutu pH kulit kepala yaitu 4,5 – 6,5. Formula yang dihasilkan menghasilkan tinggi busa yang baik. Sediaan sampo yang dibuat dari ketiga formula homogen dan kental

The Crystal Structure of the Transcriptional Regulator HucR from Deinococcus radiodurans Reveals a Repressor Preconfigured for DNA Binding

We report here the 2.3 Å resolution structure of the hypothetical uricase regulator (HucR) from Deinococcus radiodurans R1. HucR, a member of the MarR family of DNA-binding proteins, was previously shown to repress its own expression as well as that of a uricase, a repression that is alleviated both in vivo and in vitro upon binding uric acid, the substrate for uricase. As uric acid is a potent scavenger of reactive oxygen species, and as D. radiodurans is known for its remarkable resistance to DNA-damaging agents, these observations indicate a novel oxidative stress response mechanism. The crystal structure of HucR in the absence of ligand or DNA reveals a dimer in which the DNA recognition helices are preconfigured for DNA binding. This configuration of DNA-binding domains is achieved through an apparently stable dimer interface that, in contrast to what is observed in other MarR homologs for which structures have been determined, shows little conformational heterogeneity in the absence of ligand. An additional amino-terminal segment, absent from other MarR homologs, appears to brace the principal helix of the dimerization interface. However, although HucR is preconfigured for DNA binding, the presence of a stacked pair of symmetry-related histidine residues at a central pivot point in the dimer interface suggests a mechanism for a conformational change to attenuate DNA binding. © 2006 Elsevier Ltd. All rights reserved