Consistency of Bayes factor for nonnested model selection when the model dimension grows

Zellner's $g$-prior is a popular prior choice for the model selection problems in the context of normal regression models. Wang and Sun [J. Statist. Plann. Inference 147 (2014) 95-105] recently adopt this prior and put a special hyper-prior for $g$, which results in a closed-form expression of Bayes factor for nested linear model comparisons. They have shown that under very general conditions, the Bayes factor is consistent when two competing models are of order $O(n^{\tau})$ for $\tau <1$ and for $\tau=1$ is almost consistent except a small inconsistency region around the null hypothesis. In this paper, we study Bayes factor consistency for nonnested linear models with a growing number of parameters. Some of the proposed results generalize the ones of the Bayes factor for the case of nested linear models. Specifically, we compare the asymptotic behaviors between the proposed Bayes factor and the intrinsic Bayes factor in the literature.Comment: Published at http://dx.doi.org/10.3150/15-BEJ720 in the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

Us vs. Them: A Dataset of Populist Attitudes, News Bias and Emotions

Computational modelling of political discourse tasks has become an increasingly important area of research in natural language processing. Populist rhetoric has risen across the political sphere in recent years; however, computational approaches to it have been scarce due to its complex nature. In this paper, we present the new $\textit{Us vs. Them}$ dataset, consisting of 6861 Reddit comments annotated for populist attitudes and the first large-scale computational models of this phenomenon. We investigate the relationship between populist mindsets and social groups, as well as a range of emotions typically associated with these. We set a baseline for two tasks related to populist attitudes and present a set of multi-task learning models that leverage and demonstrate the importance of emotion and group identification as auxiliary tasks.Comment: Camera-ready version in EACL 202

Detecting Interference in A/B Testing with Increasing Allocation

In the past decade, the technology industry has adopted online randomized controlled experiments (a.k.a. A/B testing) to guide product development and make business decisions. In practice, A/B tests are often implemented with increasing treatment allocation: the new treatment is gradually released to an increasing number of units through a sequence of randomized experiments. In scenarios such as experimenting in a social network setting or in a bipartite online marketplace, interference among units may exist, which can harm the validity of simple inference procedures. In this work, we introduce a widely applicable procedure to test for interference in A/B testing with increasing allocation. Our procedure can be implemented on top of an existing A/B testing platform with a separate flow and does not require a priori a specific interference mechanism. In particular, we introduce two permutation tests that are valid under different assumptions. Firstly, we introduce a general statistical test for interference requiring no additional assumption. Secondly, we introduce a testing procedure that is valid under a time fixed effect assumption. The testing procedure is of very low computational complexity, it is powerful, and it formalizes a heuristic algorithm implemented already in industry. We demonstrate the performance of the proposed testing procedure through simulations on synthetic data. Finally, we discuss one application at LinkedIn, where a screening step is implemented to detect potential interference in all their marketplace experiments with the proposed methods in the paper

Maternal and offspring high-fat diet leads to platelet hyperactivation in male mice offspring

Maternal over-nutrition increases the risk of diabetes and cardiovascular events in offspring. While prominent effects on cardiovascular health are observed, the impact on platelet physiology has not been studied. Here, we examined whether maternal high-fat diet (HF) ingestion affects the platelet function in lean and obese offspring. C57BL6/N mice dams were given a HF or control (C) diet for 8 weeks before and during pregnancy. Male and female offspring received C or HF diets for 26 weeks. Experimental groups were: C/C, dam and offspring fed standard laboratory diet; C/HF dam fed standard laboratory diet and offspring fed HF diet; HF/C and HF/HF. Phenotypic and metabolic tests were performed and blood collected for platelet studies. Compared to C/C, offspring HF groups were obese, with fat accumulation, hyperglycaemia and insulin resistance. Female offspring did not present platelet hyperactivity, hence we focused on male offspring. Platelets from HF/HF mice were larger, hyperactive and presented oxidative stress when compared to C/C. Maternal and offspring HF diet results in platelet hyperactivation in male mouse offspring, suggesting a novel ‘double-hit’ effect

PENGEMBANGAN MATHEMATICAL COMIC UNTUK PENCAPAIAN KEMAMPUAN PEMECAHAN MASALAH MATEMATIS DAN KONFIRMASI NORMA SOSIOMATEMATIKA

Penelitian ini bertujuan (1) mendapatkan media mathematical comic untuk pencapaian kemampuan memecahkan masalah matematis dan mengkonfirmasi norma sosiomatematika; (2) Mengetahui tanggapan guru dan siswa terhadap mathematical comic yang telah didesain; (3) mengetahui perbedaan kemampuan memecahkan masalah matematis antara siswa yang menggunakan mathematical comic dengan yang tidak menggunakannya; (4) mengetahui kemampuan siswa dalam memecahkan masalah matematis antara perkembangan kognitif kongkrit, transisi dan formal, setelah menggunakan mathematical comic; (5) mengkonfimasi aspek pengalaman matematis, penjelasan matematis, perbedaan matematis dan komunikasi matematis dapat membangun norma sosiomatematika; dan (6) mengetahui sosiograph yang terbentuk dari norma sosiomatematika. Metode penelitian yang digunakan adalah penelitian pengembangan yang mengacu pada tahapan pendefinisian, perancangan, pengembangan dan penyebaran. Hasil penelitian menunjukkan bahwa (1) diperoleh dua buku mathematical comic yang dikembangkan dengan mendekatkan konteks matematika yang besifat abstrak menjadi matematika yang mudah dipahami oleh siswa. (2) Tanggapan siswa dan guru terhadap mathematical comic yang telah didesain berada pada kategori sangat baik. (3) Kemampuan siswa dalam memecahkan masalah segiempat dengan menggunakan mathematical comic lebih baik jika dibandingkan dengan siswa yang tidak menggunakan mathematical comic. (4) Setelah menggunakan media mathematical comic, diperoleh bahwa kemampuan memecahkan masalah matematis pada siswa dengan perkembangan kognitif transisi dan kongkrit kebih baik jika dibandingkan dengan perkembangan kognitif formal. (5) secara umum bahwa aspek pengalaman matematis, penjelasan matematis, perbedaan matematis dan komunikasi matematis dapat membangun norma sosiomatematik. (6) sosiograph yang terbentuk dari norma sosiomatematika pada siswa kelas VII, terbagi menjadi 5 kelompok yang berpusat pada siswa nomor 20, 22, 19, 23, dan 27. This study aims (1) to obtain mathematical comic media for the achievement of the ability to solve mathematical problems and confirm sociomathematics norms; (2) to determine the response of teachers and students to Mathematical comics that have been designed; (3) to determine differences in the ability to solve mathematical problems between students who use mathematical comics and those who do not use them; (4) to determine the ability of students to solve mathematical problems between concrete cognitive development, transition, and formal, after using mathematical comics; (5) to confirm aspects of mathematical experience, mathematical explanations, mathematical differences, and mathematical communication can build sociomathematical norms; (6) to determine the sociograph that is formed from sociomathematical norms. The research method used is development research, which refers to the stages of defining, designing, developing, and disseminating. The results showed that (1) two mathematical comic books were developed, which brought the abstract mathematical context closer to mathematics that was easily understood by students; (2) Student and teacher responses to mathematical comics that have been designed are in the excellent category; (3) The ability of students to solve quadrilateral problems using mathematical comics is better when compared to students who do not use mathematical comics; (4) After using mathematical comic media, it is found that the ability to solve mathematical problems in students with cognitive and transition cognitive development is better when compared to formal cognitive development; (5) in general that aspects of mathematical experience, mathematical explanations, mathematical differences, and mathematical communication can build sociomathematical norms; and (6) Sociograph, which is formed from sociomathematical norms in grade VII students, is divided into five groups, which are centered on students numbers 20, 22, 19, 23, and 27

Understanding the Seasonality of Campylobacter Infection among Commercial Broiler Chickens in the United Kingdom

Campylobacter spp. are responsible for more cases of gastroenteritis than any other bacteria in humans. Up to 80% of cases originate from poultry. Infections in both chickens and humans follow a seasonal pattern, with an increase in incidence during warmer months. This study aims to determine which causal factors are associated with the seasonal onset of Campylobacter infection in housed chickens. Eleven farms around Herefordshire, UK, were assessed daily for Campylobacter spp. presence by quantitative PCR on swabs taken inside one chicken house per farm. Weather, farm performance indicators and background information about each farm were recorded and used in statistical models to determine the strength of association between parameters and Campylobacter presence. Increased detections of Campylobacter were associated with wooden house construction, and how well temperature and humidity were managed within the house. A subset of four farms was observed for a further seven production cycles, with the same sampling regime as before, along with paired daily swabs of the external farm environment. At slaughter, sections of ilea were collected, tested for Campylobacter presence by PCR and for gut damage using histopathology, and caecal contents were collected for community 16S rRNA gene analysis. Damage to ileal villi was observed primarily in summer months. The diversity of caecal bacteria increased with Campylobacter infection and during summer months. Campylobacter infection of chickens was found to be unlikely to originate from the farmyard environment. Changes to the chicken gut were identified as varying with season, in similar patterns as observed under Campylobacter infection. This study identifies risk factors associated with Campylobacter infection that will guide how future chicken farms may be constructed to improve control of Campylobacter contamination risk factors, and proposes interaction between chicken gut microbiota and the environment inside the chicken house as being a potential explanation of Campylobacter seasonality

CHARACTERIZING DROUGHT ADAPTATIONS, PHENOTYPIC PLASTICITY, AND FIXED GENE EXPRESSION PATTERNS WITHIN QUERCUS

This dissertation was written on topics related to the genus Quercus with a primary focus on Quercus ellipsoidalis (northern pin oak) and Quercus rubra (northern red oak). Within this dissertation are chapters related to the setup of experimental common gardens within the Ford and Kellogg experimental forest, a literature review describing drought adaptations of Quercus sect. Lobatae (red oak group), identification of transcription factors within the Q. robur (English oak) and Q. rubra genomes, a study comparing leaf trait phenotypic plasticity of Q. ellipsoidalis and Q. rubra, and an RNA-seq experiment studying ecological speciation between Q. ellipsoidalis and Q. rubra. Within these studies, I found that Q. ellipsoidalis and Q. rubra have similar leaf trait phenotypic plasticity, and unique molecular phenotypes related to upregulation of genes related to photosynthesis and innate immune response, respectively. Within the Q. rubra genome, I identified multiple regions of transcription factor gene clusters that could have a significant role related to drought adaptation for this species