What Explains Schooling Differences Across Countries?

This paper provides a theory that explains the cross-country distribution of average years of schooling, as well as the so called human capital premium puzzle. In our theory, credit frictions as well as differences in access to public education, fertility and mortality turn out to be the key reasons why schooling differs across countries. Differences in growth rates and in wages are second order.human capital, per capita income differences, life expectancy, public education spending, life cycle model

Dissipative dark matter explains rotation curves

Dissipative dark matter, where dark matter particles interact with a massless (or very light) boson, is studied. Such dark matter can arise in simple hidden sector gauge models, including those featuring an unbroken $U(1)'$ gauge symmetry, leading to a dark photon. Previous work has shown that such models can not only explain the LSS and CMB, but potentially also dark matter phenomena on small scales, such as the inferred cored structure of dark matter halos. In this picture, dark matter halos of disk galaxies not only cool via dissipative interactions but are also heated via ordinary supernovae (facilitated by an assumed photon - dark photon kinetic mixing interaction). This interaction between the dark matter halo and ordinary baryons, a very special feature of these types of models, plays a critical role in governing the physical properties of the dark matter halo. Here, we further study the implications of this type of dissipative dark matter for disk galaxies. Building on earlier work, we develop a simple formalism which aims to describe the effects of dissipative dark matter in a fairly model independent way. This formalism is then applied to generic disk galaxies. We also consider specific examples, including NGC 1560 and a sample of dwarf galaxies from the LITTLE THINGS survey. We find that dissipative dark matter, as developed here, does a fairly good job accounting for the rotation curves of the galaxies considered. Not only does dissipative dark matter explain the linear rise of the rotational velocity of dwarf galaxies at small radii, but it can also explain the observed wiggles in rotation curves which are known to be correlated with corresponding features in the disk gas distribution.Comment: About 20 page

A Theory Explains Deep Learning

This is our journal for developing Deduction Theory and studying Deep Learning and Artificial intelligence. Deduction Theory is a Theory of Deducing World’s Relativity by Information Coupling and Asymmetry. We focus on information processing, see intelligence as an information structure that relatively close object-oriented, probability-oriented, unsupervised learning, relativity information processing and massive automated information processing. We see deep learning and machine learning as an attempt to make all types of information processing relatively close to probability information processing. We will discuss about how to understand Deep Learning and Artificial intelligence and why Deep Learning is shown better performance than the other methods by metaphysical logic

Singlet Fermionic Dark Matter explains DAMA signal

It has been suggested that, considering channeling effect, the order of a few GeV dark matters which are elastically scattered from detector nuclei might be plausible candidates reconciling the DAMA annual modulation signal with the results of other null experiments. We show that Singlet Fermionic Dark Matter can be such a dark matter candidate, simultaneously providing the correct thermal relic density which is consistent with the WMAP data.Comment: 9 pages, 3 figure

What explains Hadza food sharing?

Most hypotheses proposed to explain human food sharing address motives, yet most tests of these hypotheses have measured only the patterns of food transfer. To choose between these hypotheses we need to measure peopleç—´ propensity to share. To do that, I played two games (the Ultimatum and Dictator Games) with Hadza hunter-gatherers. Despite their ubiquitous food sharing, the Hadza are less willing to share in these games than people in complex societies are. They were also less willing to share in smaller camps than larger camps. I evaluate the various food-sharing hypotheses in light of these results.

K-essence Explains a Lorentz Violation Experiment

Recently, a state of the art experiment shows evidence for Lorentz violation in the gravitational sector. To explain this experiment, we investigate a spontaneous Lorentz violation scenario with a generalized scalar field. We find that when the scalar field is nonminimally coupled to gravity, the Lorentz violation induces a deformation in the Newtonian potential along the direction of Lorentz violation.Comment: 8 pages, the final version, discussion and references adde

What Explains Household Stock Holdings?

This is an empirical study of the determinants of stock holdings using data from the U.S. Survey of Consumer Finances from 1992 to 2001. There is a great heterogeneity in the way households form their portfolios. Stock ownership is positively correlated with various measures of wealth, age, retirement savings, and having sought financial advice. It is negatively correlated with holdings of alternative risky investments, such as investments in private businesses, and with the willingness to undertake non-financial investments in the future. While we can predict reasonably well who holds stocks, we have less predictive power about the share of stocks owned by those who hold positive amounts.Portfolio choice, stock holdings, consumer finances.

Macromolecular crowding explains overflow metabolism in cells

Overflow metabolism is a metabolic phenotype of cells characterized by mixed oxidative phosphorylation (OxPhos) and fermentative glycolysis in the presence of oxygen. Recently, it was proposed that a combination of a protein allocation constraint and a higher proteome fraction cost of energy generation by OxPhos relative to fermentation form the basis of overflow metabolism in the bacterium, Escherichia coli. However, we argue that the existence of a maximum or optimal macromolecular density is another essential requirement. Here we re-evaluate our previous theory of overflow metabolism based on molecular crowding following the proteomic fractions formulation. We show that molecular crowding is a key factor in explaining the switch from OxPhos to overflow metabolism