A unified approach to χ2\chi^2 discriminators for searches of gravitational waves from compact binary coalescences

We describe a general mathematical framework for $\chi^2$ discriminators in the context of the compact binary coalescence search. We show that with any $\chi^2$ is associated a vector bundle over the signal manifold, that is, the manifold traced out by the signal waveforms in the function space of data segments. The $\chi^2$ is then defined as the square of the $L_2$ norm of the data vector projected onto a finite dimensional subspace (the fibre) of the Hilbert space of data trains and orthogonal to the signal waveform - any such fibre leads to a $\chi^2$ discriminator and the full vector bundle comprising the subspaces and the base manifold constitute the $\chi^2$ discriminator. We show that the $\chi^2$ discriminators used so far in the CBC searches correspond to different fiber structures constituting different vector bundles on the same base manifold, namely, the parameter space. The general formulation indicates procedures to formulate new $\chi^2$s which could be more effective in discriminating against commonly occurring glitches in the data. It also shows that no $\chi^2$ with a reasonable degree of freedom is foolproof. It could also shed light on understanding why the traditional $\chi^2$ works so well. As an example, we propose a family of ambiguity $\chi^2$ discriminators that is an alternative to the traditional one. Any such ambiguity $\chi^2$ makes use of the filtered output of the template bank, thus adding negligible cost to the overall search. We test the performance of ambiguity $\chi^2$ on simulated data using spinless TaylorF2 waveforms. We show that the ambiguity $\chi^2$ essentially gives a clean separation between glitches and signals. Finally, we investigate the effects of mismatch between signal and templates on the $\chi^2$ and also further indicate how the ambiguity $\chi^2$ can be generalized to detector networks for coherent observations.Comment: 21 pages, 5 figure, abstract is shortened to comply with the arXiv's 1920 characters limitation, v2: accepted for publication in PR

Tackling excess noise from bilinear and nonlinear couplings in gravitational-wave interferometers

We describe a tool we improved to detect excess noise in the gravitational wave (GW) channel arising from its bilinear or nonlinear coupling with fluctuations of various components of a GW interferometer and its environment. We also describe a higher-order statistics tool we developed to characterize these couplings, e.g., by unraveling the frequencies of the fluctuations contributing to such noise, and demonstrate its utility by applying it to understand nonlinear couplings in Advanced LIGO engineering data. Once such noise is detected, it is highly desirable to remove it or correct for it. Such action in the past has been shown to improve the sensitivity of the instrument in searches of astrophysical signals. If this is not possible, then steps must be taken to mitigate its influence, e.g., by characterizing its effect on astrophysical searches. We illustrate this through a study of the effect of transient sine-Gaussian noise artifacts on a compact binary coalescence template bank.Comment: 8 pages and 7 figure

Politik der Frauenförderung in staatlichen und nichtstaatlichen Entwicklungshilfeorganisationen im internationalen Vergleich

Die Thematik „Frauen und Entwicklung” ist seit 1970 im Gespräch. Jedoch erst seit kurzem wird der beträchtliche Beitrag der Frauen an der Entwicklung auch offiziell anerkannt. Trotz der internationalen Frauendekade mit den drei internationalen Konferenzen und der Fülle von Untersuchungen über Frauen aus allen Teilen der Welt hat sich die Lebenssituation der meisten Frauen im Süden kaum wesentlich verbessert. Heute, zwei Jahre nach der internationalen Frauenkonferenz in Nairobi, ringt die „Fra..

Reinventing the Utility for DERs: A Proposal for a DSO-Centric Retail Electricity Market

The increasing penetration of intermittent renewables, storage devices, and flexible loads is introducing operational challenges in distribution grids. The proper coordination and scheduling of these resources using a distributed approach is warranted, and can only be achieved through local retail markets employing transactive energy schemes. To this end, we propose a distribution-level retail market operated by a Distribution System Operator (DSO), which schedules DERs and determines the real-time distribution-level Locational Marginal Price (d-LPM). The retail market is built using a distributed Proximal Atomic Coordination (PAC) algorithm, which solves the optimal power flow model while accounting for network physics, rendering locationally and temporally varying d-LMPs. A numerical study of the market structure is carried out via simulations of the IEEE-123 node network using data from ISO-NE and Eversource in Massachusetts, US. The market performance is compared to existing retail practices, including demand response (DR) with no-export rules and net metering. The DSO-centric market increases DER utilization, permits continual market participation for DR, lowers electricity rates for customers, and eliminates the subsidies inherent to net metering programs. The resulting lower revenue stream for the DSO highlights the evolving business model of the modern utility, moving from commoditized markets towards performance-based ratemaking

Retrospective Surveillance for Intussusception in Children Aged Less than Five Years in a South Indian Tertiary-care Hospital

To facilitate the assessment of the safety profile of rotavirus vaccines effectively, baseline data on intussusception are important for comparison with intussusception rates following the introduction of vaccine. The aim of the study was to describe epidemiological and clinical features of intussusception in children aged less than five years in an Indian medical facility. Hospital data on intussusception for children discharged during 1 January 2001–30 June 2004 from the Christian Medical College Hospital, Vellore, India, were reviewed. Relevant information was extracted from medical records to classify cases according to the criteria of the Brighton Collaboration Intussusception Working Group. Complete review of medical records for clinical and demographic information was only performed for those cases fulfilling level 1 diagnostic certainty (definite intussusception) (Study ID 101245). During the surveillance period, 31 infants and children with definite intussusception were identified. The majority (61.2%) of the cases occurred in the first year of life. The male : female ratio was 3.4 : 1. Intussusception cases occurred round the year with no distinct seasonality. No intussusception-associated death was recorded. This study provides baseline data on intussusception in South India. Cases identified in the study were similar in presentation and demographics as those observed in other Asian settings. Prospective surveillance systems, using standardized case definitions will further increase the understanding of the aetiology and epidemiology of intussusception, especially as new rotavirus vaccines are made available

Trends in caesarean section rates in a rural block of southern India

Background: Over the last decade many programmes have been implemented to improve the health of pregnant women and neonates. This study aims to look at the changes in modes of delivery and perinatal mortality rates in a rural block of Tamil Nadu between 2006 and 2015.Methods: Data on all the births that have occurred in this rural block of Tamil Nadu that has been prospectively collected between 2006 and 2015 was analysed. A longitudinal analysis was done to calculate the primary and overall caesarean section rate and the average annual rate of increase. The perinatal mortality rate was also calculated.Results: The primary LSCS rate has increased from 9.08% in 2005 to 16.1% in 2015. The overall caesarean section rate has increased from 11.7% to 19.2% in the same time with an average annual rate of increase of 5.1%. During this period the perinatal mortality has decreased from 33 per 1000 live births to 17 per 1000 live births.Conclusions: Though the overall caesarean section rate is higher than the 15% prescribed by WHO the rates are lower than the rest of the country and rural Tamil Nadu

Strengthening Health Systems and Improving the Capacity of Pediatric Care Centers to Respond to Epidemics Such as COVID-19 in Resource-limited Settings

The coronavirus disease-2019 (COVID-19) pandemic has highlighted in dramatic fashion the weaknesses of health systems worldwide in responding to emerging pandemics [1]. Although many governments, nongovernment organizations (NGOs) and multinational organizations like the World Health Organization (WHO) have prioritized the strengthening of health systems, and developed pandemic preparedness plans, the world’s uneven (and often belated) response to the COVID-19 pandemic suggests that many of these plans were insufficient and that the global health community will need to improve resource allocation, information-sharing and government coordination in order to minimize the impact of future outbreaks [2]. We are particularly concerned that existing preparedness plans do not adequately address the special needs of children; the relatively low hospitalization and death rates of children in the COVID-19 pandemic may result in the continuation of those needs being overlooked [3]. Additionally, the needs of children in low-resource settings, which differ in many ways from those of wealthier settings, may be even further at stake. As health systems begin to reassess their preparedness plans, this pandemic gives the world the opportunity to put safety measures in place to protect children now, and in turn to prepare for future outbreaks that will, sooner or later, affect children to a greater degree than this pandemic has thus far