Tehran may further restrict foreign social media

Significance This comes as conservative-drafted legislation aims to increase use of local alternatives to facilitate new restrictions on foreign social media providers. The recent presidential election highlighted their use by reformists, particularly Clubhouse, which hosted unusually open discussions. Impacts New restrictions on social media are likely to have a negative economic impact on many businesses. Open policy discussions may continue on Clubhouse and other apps but could become increasingly dominated by the diaspora. The July 21 removal of Clubhouse’s invitation-only system could potentially undermine its distinctive appeal to nervous dissidents.

Plum Tree Gums as Local Alternatives for Foreign Drilling Fluid Materials

A few years ago oil well drilling cost increased due to using modern technique such as equipment and materials that are used by specialist companies so studies and researches were required to decrease these costs. In this study we tried to find local alternatives for foreign drilling fluid materials that are aimed to decrease oil well drilling cost although the cost of drilling fluid materials reach to 30 % of total materials cost of drilling oil well. In the first part of this study seven local materials and it's tested under API Specification 13A for Drilling Fluids Materials were investigated. Plum Tree Gum was succeeded in this test among several other materials as drilling fluid materials. The second part of this study was a comparison between these local alternative and similar foreign materials for same sample to show physical and rheological properties. The third part of this study was tested this local alternative under different values temperature to show effect the temperature on physical and rheological properties of this local alternative. The results approved that; Plum Tree Gum, local alternative, can use as filtration control materials for water based drilling fluid. Also this local alternative increased viscosity as minimal for water based drilling fluids, So it can be used as part alternative for Bentonite to increase viscosity by increasing Yield point and decreasing solids concentration in drilling fluids so it has positive effect on Rig equipment’s and Pay-zone. Plum Tree Gum is Ore polymers (plant origin)

On testing marginal versus conditional independence

Summary We consider testing marginal independence versus conditional independence in a trivariate Gaussian setting. The two models are nonnested, and their intersection is a union of two marginal independences. We consider two sequences of such models, one from each type of independence, that are closest to each other in the Kullback–Leibler sense as they approach the intersection. They become indistinguishable if the signal strength, as measured by the product of two correlation parameters, decreases faster than the standard parametric rate. Under local alternatives at such a rate, we show that the asymptotic distribution of the likelihood ratio depends on where and how the local alternatives approach the intersection. To deal with this nonuniformity, we study a class of envelope distributions by taking pointwise suprema over asymptotic cumulative distribution functions. We show that these envelope distributions are well behaved and lead to model selection procedures with rate-free uniform error guarantees and near-optimal power. To control the error even when the two models are indistinguishable, rather than insist on a dichotomous choice, the proposed procedure will choose either or both models.

Beyond Just the Average Effect: Variation in Head Start Treatment Effects on Parenting Behavior

Parent engagement has been a cornerstone of Head Start since its inception in 1965. Prior studies have found evidence for small to moderate impacts of Head Start on parenting behaviors but have not considered the possibility that individual Head Start programs might vary meaningfully in their effectiveness at improving parenting outcomes. The present study uses the Head Start Impact Study to examine the average effect of random assignment to and participation in Head Start on parenting outcomes as well as variation in that effect across Head Start programs. Findings reveal that Head Start is effective on average at promoting parents’ daily reading and overall literacy and math activities with children but that effects vary significantly for parents’ literacy and math activities, with some programs much more and some much less effective than their local alternatives. Findings also demonstrate that Head Start has consistent near-zero impacts across centers on parents’ disciplinary interactions with children.

AN ADAPTIVE TEST OF STOCHASTIC MONOTONICITY

We propose a new nonparametric test of stochastic monotonicity which adapts to the unknown smoothness of the conditional distribution of interest, possesses desirable asymptotic properties, is conceptually easy to implement, and computationally attractive. In particular, we show that the test asymptotically controls size at a polynomial rate, is nonconservative, and detects certain smooth local alternatives that converge to the null with the fastest possible rate. Our test is based on a data-driven bandwidth value and the critical value for the test takes this randomness into account. Monte Carlo simulations indicate that the test performs well in finite samples. In particular, the simulations show that the test controls size and, under some alternatives, is significantly more powerful than existing procedures.

A nondegenerate Vuong test and post selection confidence intervals for semi/nonparametric models

This paper proposes a new model selection test for the statistical comparison of semi/non‐parametric models based on a general quasi‐likelihood ratio criterion. An important feature of the new test is its uniformly exact asymptotic size in the overlapping nonnested case, as well as in the easier nested and strictly nonnested cases. The uniform size control is achieved without using pretesting, sample‐splitting, or simulated critical values. We also show that the test has nontrivial power against all n ‐local alternatives and against some local alternatives that converge to the null faster than n . Finally, we provide a framework for conducting uniformly valid post model selection inference for model parameters. The finite sample performance of the nondegenerate test and that of the post model selection inference procedure are illustrated in a mean‐regression example by Monte Carlo.