The Skyrme Model piNN Form Factor and the Sea Quark Distribution of the Nucleon

We calculate the sea quark distribution of the nucleon in a meson cloud model. The novel feature of our calculation is the implementation of a special piNN form factor recently obtained by Holzwarth and Machleidt. This form factor is hard for small and soft for large momentum transfers. We show that this feature leads to a substantial improvement.Comment: 9 pages, 5 figures; v2: some typos corrected, including eq. (9

Polarized antiquark flavor asymmetry: Pauli blocking vs. the pion cloud

The flavor asymmetry of the unpolarized antiquark distributions in the proton, dbar(x) - ubar(x) > 0, can qualitatively be explained either by Pauli blocking by the valence quarks, or as an effect of the pion cloud of the nucleon. In contrast, predictions for the polarized asymmetry Delta_ubar(x) - Delta_dbar(x) based on rho meson contributions disagree even in sign with the Pauli blocking picture. We show that in the meson cloud picture a large positive Delta_ubar(x) - Delta_dbar(x) is obtained from pi-N - sigma-N interference-type contributions, as suggested by chiral symmetry. This effect restores the equivalence of the 'quark' and 'meson' descriptions also in the polarized case.Comment: 4 pages, revtex, 3 eps figure

Vacuum fluctuations and the thermodynamics of chiral models

We consider the thermodynamics of chiral models in the mean-field approximation and discuss the relevance of the (frequently omitted) fermion vacuum loop. Within the chiral quark-meson model and its Polyakov loop extended version, we show that the fermion vacuum fluctuations can change the order of the phase transition in the chiral limit and strongly influence physical observables. We compute the temperature-dependent effective potential and baryon number susceptibilities in these models, with and without the vacuum term, and explore the cutoff and the pion mass dependence of the susceptibilities. Finally, in the renormalized model the divergent vacuum contribution is removed using the dimensional regularization.Comment: 9 pages, 5 figure

Research and development in CdS photovoltaic film cells Third quarterly progress report, 1 Dec. 1962 - 28 Feb. 1963

Large cadmium sulfide thin film photovoltaic cell

Development of cadmium sulfide photovoltaic film cells Final report

Controlled carrier concentrations and improved cell conversion efficiencies in cadmium sulfide photovoltaic film cel

One million additional children in poverty since 2009: 2010 data reveal nearly one in four southern children now live in poverty

In this brief, the authors use the ACS data released on September 22 to focus on child poverty. The authors report that between 2009 and 2010 an additional one million children joined the ranks of those in poverty. This brings the total to an estimated 15.7 million poor children in 2010, an increase of 2.6 million since the Great Recession began in 2007

Cause for Optimism? Child Poverty Declines for the First Time Since Before the Great Recession

New data released on September 18, 2014, by the U.S. Census Bureau indicate that child poverty fell by 0.4 percentage point between 2012 and 2013, to 22.2 percent. Though still significantly higher than in 2007 when the Great Recession hit (18.0 percent), and higher than at its conclusion (20.0 percent) in 2009, the decline from 2012 may be cause for optimism. Estimates suggest the number of poor children declined by roughly 300,000 between 2012 and 2013

Child Care Costs Exceed 10 Percent of Family Income for One in Four Families

In this brief, authors Marybeth Mattingly, Andrew Schaefer, and Jessica Carson analyze families’ child care expenses and identify, among families with young children who pay for child care, the share that are “cost burdened,” defined in this context as spending more than 10 percent of their gross income on child care. Using data from the 2012–2016 Current Population Survey, they present their findings by number of children; age of youngest child; parental characteristics; family income measures; and U.S. region, metropolitan status, and state. They report that about one in four families with young children who have child care costs are “burdened” by the cost, spending more than 10 percent of family income on child care. Across families with young children, an average of 8.8 percent of family income is spent on child care. More than half of poor families with young children are cost burdened by child care, compared to 39.3 percent of low income families (those with incomes between one and two times the poverty threshold) and just 13.4 percent of families at or above five times the poverty threshold. One in five married couples, and two in five single parents with young children and child care expenses, pay more than 10 percent of their income on these costs. Access to quality, affordable child care is critical for American working families

2016 Child Poverty Rate Sees Largest Decline Since Before Great Recession

Child poverty declined by 1.2 percentage points between 2015 and 2016, according to analyses of the official poverty measure (OPM) in the latest American Community Survey