Randomization Inference for Outcomes with Clumping at Zero

While randomization inference is well developed for continuous and binary outcomes, there has been comparatively little work for outcomes with nonnegative support and clumping at zero. Typically, outcomes of this type have been modeled using parametric models that impose strong distributional assumptions. This article proposes new randomization inference procedures for nonnegative outcomes with clumping at zero. Instead of making distributional assumptions, we propose various assumptions about the nature of the response to treatment and use permutation inference for both testing and estimation. This approach allows for some natural goodness-of-fit tests for model assessment, as well as flexibility in selecting test statistics sensitive to different potential alternatives. We illustrate our approach using two randomized trials, where job training interventions were designed to increase earnings of participants.     

Model‐free causal inference of binary experimental data

For binary experimental data, we discuss randomization‐based inferential procedures that do not need to invoke any modeling assumptions. In addition to the classical method of moments, we also introduce model‐free likelihood and Bayesian methods based solely on the physical randomization without any hypothetical super population assumptions about the potential outcomes. These estimators have some properties superior to moment‐based ones such as only giving estimates in regions of feasible support. Due to the lack of identification of the causal model, we also propose a sensitivity analysis approach that allows for the characterization of the impact of the association between the potential outcomes on statistical inference.     

Standards of Care in Assessment of Lesbian,Gay, Bisexual,Transgender, Gender Expansive,and Queer/Questioning (LGBTGEQ+) Persons

ABSTRACT

A Joint Task Force comprised of members of the Association for Lesbian, Gay, Bisexual, and Transgender Issues in Counseling (ALGBTIC) and the Association for Assessment and Research in Counseling (AARC) present standards of care for assessment of Lesbian, Gay, Bisexual, Transgender, Gender Expansive, and Queer/Questioning (LGBTGEQ+) Persons.     

Proposing an Initiative Research Methodology for LGBTQ+ Youth: Photo-Elicitation and Thematic Analysis

ABSTRACT

A framework for approaching lesbian, gay, bisexual, transgender, queer+ (LGBTQ+) youth is presented that honors their voice. This methodology utilizes participant-driven photo elicitation as a qualitative data collection method, and then integrates thematic analysis. A brief review of current literature is provided to outline gaps, which establish the need to expand effective research methods with LGBTQ+ youth. Photo elicitation is explained with discussion specific to use with LGBTQ+ youth. Thematic analysis is identified and explained as an analytic approach. Challenges of implementing this methodology are discussed with attention to ethical concerns.     

A study on imbalance support vector machine algorithms for sufficient dimension reduction

Li et al. (2011 Li, B., Artemiou, A., Li, L. (2011). Principal support vector machine for linear and nonlinear sufficient dimension reduction. Ann. Stat. 39:3182–3210.[Crossref], [Web of Science ®] , [Google Scholar]) presented the novel idea of using support vector machines (SVMs) to perform sufficient dimension reduction. In this work, we investigate the potential improvement in recovering the dimension reduction subspace when one changes the SVM algorithm to treat imbalance based on several proposals in the machine learning literature. We find out that in most situations, treating the imbalanced nature of the slices will help improve the estimation. Our results are verified through simulation and real data applications.     

Modified linear programming and class 0 bounds for graph pebbling

Given a configuration of pebbles on the vertices of a connected graph G, a pebbling move removes two pebbles from some vertex and places one pebble on an adjacent vertex. The pebbling number of a graph G is the smallest integer k such that for each vertex v and each configuration of k pebbles on G there is a sequence of pebbling moves that places at least one pebble on v. First, we improve on results of Hurlbert, who introduced a linear optimization technique for graph pebbling. In particular, we use a different set of weight functions, based on graphs more general than trees. We apply this new idea to some graphs from Hurlbert’s paper to give improved bounds on their pebbling numbers. Second, we investigate the structure of Class 0 graphs with few edges. We show that every n-vertex Class 0 graph has at least \(\frac{5}{3}n - \frac{11}{3}\) edges. This disproves a conjecture of Blasiak et al. For diameter 2 graphs, we strengthen this lower bound to \(2n - 5\), which is best possible. Further, we characterize the graphs where the bound holds with equality and extend the argument to obtain an identical bound for diameter 2 graphs with no cut-vertex.     

Soil-atmosphere exchange of carbon dioxide,methane and nitrous oxide in urban garden systems: impact of irrigation,fertiliser and mulch

Urban green spaces provide important ecosystem services, such as amenity, biodiversity, productivity, climate amelioration, hydrological and biogeochemical cycling. Intensively managed urban gardens can sequester carbon through vegetation growth and soil C increase, but may experience nitrous oxide (N₂O) emissions and reduced soil methane (CH₄) uptake from irrigation and fertiliser use. Soil atmosphere exchange of N₂O, CH₄ and carbon dioxide (CO₂) was measured in lawn and wood chip mulched garden areas in Melbourne, Australia in winter, spring and summer under various water and fertiliser regimes. Gas exchange before and after lawn fertiliser application was measured continuously for three weeks using an automated chamber system. Applying fertiliser led to a peak N₂O emission of >60 μg N m⁻² h⁻¹, but overall only weekly irrigation (10 mm) significantly increased mean soil N₂O emissions above that in other treatments. Under mulch, mean soil N₂O emissions (14.0 μg N m⁻² h⁻¹) were significantly smaller than from irrigated lawn (27.9 μg N m⁻² h⁻¹), whereas mean soil CH₄ uptake under mulch (−30.7 μg C m⁻² h⁻¹) was significantly greater (p < 0.01) than in any lawn treatment. Lawns were either a weak CH₄ sink or source. Soil C density (0–25 cm) under mulch (12.5 kg C m⁻²) was greater that under lawn (8.0 kg C m⁻²). On a carbon dioxide equivalent (CO₂-e) basis, soil N₂O emissions offset the benefits of soil CH₄ uptake. Mulched garden areas provide greatest C sequestration potential in soil and vegetation and the smallest non-CO₂ emissions, as soil CH₄ uptake offsets a large fraction of soil N₂O emissions. Results of this study suggest that reducing the irrigation and fertiliser application to lawns can help mitigate GHG emissions from urban garden systems, and increasing the area of mulched perennial garden beds can also provide net GHG benefits; however, this needs to be tested in other garden systems with different soil types and environmental conditions.     

CAN ENTRY OR EXIT EVENT STUDIES INFORM HORIZONTAL MERGER ANALYSIS? EVIDENCE FROM GROCERY RETAILING

This study estimates how prices change following the entry and exit of grocery retailers. We estimate the effects of entry (exit) by comparing affected markets to a set of unaffected markets using both a difference‐in‐difference estimator and a synthetic control estimator. We find that entry typically results in reduced prices. More surprisingly, we find that exit is frequently associated with falling prices. Our estimated effects of entry on grocery prices are similar in magnitude to estimates of merger price effects in the supermarket industry. This finding suggests that entry event studies may be a useful tool for horizontal merger analysis. (JEL L11, L4, L81)     

用于研究细胞入侵的基质降解实验

在细胞正常发育、发炎和肿瘤转移研究中有一个关键步骤,就是通过多层的细胞外基质入侵细胞。在传统的研究方法中,研究者们已经发展了自己的检测方法,就是利用荧光标记的凝胶来研究基质降解,其中伴随着细胞的入侵。这篇文章探索了研究细胞入侵的新方法,能得到比传统方法更一致的结果。研究者们利用这些方法来研究降解时间过程,扫描在降解过程中潜在的活化剂或者抑制剂,探索细胞入侵的通道。     

New Labour, Work and the Family

New Labour has put support for the family at the core of its notion of the “strong community”. Across a range of policy areas the Labour government can be seen to be developing a direct and explicit family policy. But what kind of community is the government trying to shape by these policies? On the one hand, Labour appears to support the family as the basis of a more moral, dutiful and cohesive community. On the other hand, the government has given weight to policies that support social inclusion in the community through paid work. This paper examines whether there is a tension in Labour’s social policies between its emphasis on the importance of stable family life and the primacy given to paid work. Are critics like Ruth Levitas right when they argue that the government’s emphasis on paid work devalues, and is unsupportive of, unpaid work, especially caring for children and other family members? Alternatively, can this combination of communitarianisms—community as “stable family” and community as “paid work”—be seen to be marking out some “third way” on the family? We shall show that different aspects of the government’s family policies reflect different perspectives and policy agendas within New Labour and third‐way thinking more broadly. And while recognizing the tensions between work and the family, we shall suggest that they are often overstated and fail to give sufficient weight to the complementary aspects of Labour’s welfare reforms.