Higher Education, the Bane of Fertility? An investigation with the HILDA Survey

This paper uses the first wave of HILDA in an analysis of the determinants of fertility, focusing in particular on the role of education. Estimating lifetime fertility from micro data sets is generally quite difficult since a large proportion of the sample, because of their age, will have incomplete fertility. The HILDA survey allows this problem to be addressed, however, because as well as measuring the actual number of children a person has, there is also information on the additional number of children a person expects to parent. Thus it is possible to estimate the determinants of fertility in three dimensions: the actual number of children a person has, the expected future number of children, and total intended lifetime fertility, the sum of the first two. The analysis is conducted in several stages. First, total intended lifetime fertility is modelled as a function of education and a host of other variables reflecting the opportunity costs and consumption elements of child rearing. The HILDA sample allows control for a host of other factors, reflecting both attitudes and values, and their roles are examined as well. The main result is that education lowers total lifetime fertility, although the strength of this relationship falls importantly with the addition of a range of variables, such as marital history and equivalised household income. A second set of estimations concerns the determinants of the expected future number of children, controlling for the number of children a person already has. The estimations reveal that more educated people tend to have significantly higher fertility expectations than others, and that the effect is non-linear. The juxtaposition of the results of the two approaches could be interpreted to mean that higher education per se does not lower people’s fertility expectation while the more educated tend to defer their fertility and may end up with fewer children due to some unexpected constraints such as deterioration or breakdown in relationship and fecundity problems at later stage. Realising these risks before hand along with appropriate institutional and financial supports from the government may help the educated people to achieve their fertility expectation. In addition to education, all fertility measures are influenced importantly by, among others: household income (negative for the first and positive for the second); partnering (positive); the significance of religion in people’s lives (positive); and values concerning motherhood (positive). Many different specifications were explored with the main conclusions being robust. It is recognised, however, that fertility decisions are likely to be made in combination with a host of other life-cycle issues, such as investment in education, and that the results of the estimations need to be qualified by this reality.Fertility expectation; Education

Nanostructured Conductive Polymers for Advanced Energy Storage

Conductive polymers combine the attractive properties associated with conventional polymers and unique electronic properties of metals or semiconductors. Recently, nanostructured conductive polymers have aroused considerable research interest owing to their unique properties over their bulk counterparts, such as large surface areas and shortened pathways for charge/mass transport, which make them promising candidates for broad applications in energy conversion and storage, sensors, actuators, and biomedical devices. Numerous synthetic strategies have been developed to obtain various conductive polymer nanostructures, and high-performance devices based on these nanostructured conductive polymers have been realized. This Tutorial review describes the synthesis and characteristics of different conductive polymer nanostructures; presents the representative applications of nanostructured conductive polymers as active electrode materials for electrochemical capacitors and lithium-ion batteries and new perspectives of functional materials for next-generation high-energy batteries, meanwhile discusses the general design rules, advantages, and limitations of nanostructured conductive polymers in the energy storage field; and provides new insights into future directions.University of Texas at Austin3M Non-tenured Faculty awardWelch Foundation F-1861Materials Science and Engineerin

AutoAccel: Automated Accelerator Generation and Optimization with Composable, Parallel and Pipeline Architecture

CPU-FPGA heterogeneous architectures are attracting ever-increasing attention in an attempt to advance computational capabilities and energy efficiency in today's datacenters. These architectures provide programmers with the ability to reprogram the FPGAs for flexible acceleration of many workloads. Nonetheless, this advantage is often overshadowed by the poor programmability of FPGAs whose programming is conventionally a RTL design practice. Although recent advances in high-level synthesis (HLS) significantly improve the FPGA programmability, it still leaves programmers facing the challenge of identifying the optimal design configuration in a tremendous design space. This paper aims to address this challenge and pave the path from software programs towards high-quality FPGA accelerators. Specifically, we first propose the composable, parallel and pipeline (CPP) microarchitecture as a template of accelerator designs. Such a well-defined template is able to support efficient accelerator designs for a broad class of computation kernels, and more importantly, drastically reduce the design space. Also, we introduce an analytical model to capture the performance and resource trade-offs among different design configurations of the CPP microarchitecture, which lays the foundation for fast design space exploration. On top of the CPP microarchitecture and its analytical model, we develop the AutoAccel framework to make the entire accelerator generation automated. AutoAccel accepts a software program as an input and performs a series of code transformations based on the result of the analytical-model-based design space exploration to construct the desired CPP microarchitecture. Our experiments show that the AutoAccel-generated accelerators outperform their corresponding software implementations by an average of 72x for a broad class of computation kernels

Tensor stability in Born-Infeld determinantal gravity

We consider the transverse-traceless tensor perturbation of a spatial flat homogeneous and isotropic spacetime in Born-Infeld determinantal gravity, and investigate the evolution of the tensor mode for two solutions in the early universe. For the first solution where the initial singularity is replaced by a regular geometric de Sitter inflation of infinite duration, the evolution of the tensor mode is stable for the parameter spaces $\alpha<-1$, $\omega\geq-1/3$ and $\alpha=-1$, $\omega>0$. For the second solution where the initial singularity is replaced by a primordial brusque bounce, which suffers a sudden singularity at the bouncing point, the evolution of the tensor mode is stable for all regions of the parameter space. Our calculation suggests that the tensor evolution can hold stability in large parameter spaces, which is a remarkable property of Born-Infeld determinantal gravity. We also constrain the theoretical parameter $|\lambda|\geq 10^{-38} \text{m}^{-2}$ by resorting to the current bound on the speed of the gravitational waves.Comment: 14 pages, added a general discussion on the tensor stability in Sec. 3, and added Sec. 5 on the parameter constraint, published versio

Full linear perturbations and localization of gravity on f(R,T)f(R,T) brane

We study the thick brane world system constructed in the recently proposed $f(R,T)$ theories of gravity, with $R$ the Ricci scalar and $T$ the trace of the energy-momentum tensor. We try to get the analytic background solutions and discuss the full linear perturbations, especially the scalar perturbations. We compare how the brane world model is modified with that of general relativity coupled to a canonical scalar field. It is found that some more interesting background solutions are allowed, and only the scalar perturbation mode is modified. There is no tachyon state exists in this model and only the massless tensor mode can be localized on the brane, which recovers the effective four-dimensional gravity. These conclusions hold provided that two constraints on the original formalism of the action are satisfied.Comment: v3: 8 pages, 2 figures, improved version with minor corrections, accepted by EPJ