School Flexibility and Accountability

This report presents a discussion and a menu of alternatives for school flexibility and accountability

Racial and ethnic inequality in Latin America

This chapter examines socioeconomic inequality in Latin America through the lens of race and ethnicity. We primarily use national census data from the International Public Use Micro Data Sample (IPUMS). Since censuses use inconsistent measures of race and ethnicity, we also draw on two additional measures from the Latin American Public Opinion Project (LAPOP). Unlike censuses, LAPOP data offer a more consistent ethnoracial scheme across countries and a unique interviewer-rated skin color measure. Our study shows that black and indigenous populations and those with darker skin color experience educational, income, and occupational disadvantages, even after controlling for their social origins. However, inequality and hierarchical ordering of Afro-descendants, indigenous peoples, mestizos, whites, and others vary across countries. We include an extended examination of educational inequality in Brazil, the region’s largest country. The chapter concludes with an exploration of public policy approaches to address black and indigenous disadvantage across Latin America while also highlighting the case of Brazil, where targeted antiracism policy is most advanced

Metallkomplexe mit biologisch wichtigen Liganden, LXV

Cp*Co(CO)I2 (Cp* = 5-C5Me5), [(6-arene)RuCl2]2 (arene = p-cymene, hexamethylbenzene), and [Cp*MCl2]2 (M = Rh, Ir) react with -amino amides and various peptide esters to give the N,O-chelate complexes [Cp*(I)Co - NH2C(H)(R1)C(NHR2)-O]+ (1), [(6-arene)(Cl)Ru - NH2C(H)(R1)C(NHR2)O]+ (2), and [CP*(Cl)M - NH2CH2C(NHR)O]+ (M = Rh, Ir) (5, in solution), respectively. In the solid state the ligands are 1N-bonded in 5. By deprotonation of the peptide bond in 2 and 5 the neutral N, N-chelate complexes (6-arene)(Cl)Ru - NH2C(H)(R1)C(O)-2 (6) and Cp*(Cl)M - NH2C(H)(R1)C(O)NR2 (M = Rh, Ir) (7) have been obtained. Glycinenitrile is 1-bonded in (6-p-cymene)(Cl)2Ru(NH2CH2CN) (3) and Cp*(Cl)2Rh(NH2CH2CN) (4). Double deprotonated triglycine methyl ester is a N,N,N-tridentate ligand in (6-C6Me6)Ru(NH2CH2C(O)NCH2C(O)-NCH2CO2Me) (8). The anions of L-asparagine and of aspartame (L-aspartyl-L-phenylalanine methyl ester) give the complexes 9-12 with tridentate O,N,O- or O,N,N-chelate ligands. The crystal structures of 1d (L = glyglyOEt), 5a (L = glycinamide), 6e (L = glyglyOEt), and 7k (L = glyglyglyOEt) have been determined by X-ray structural analysis

Percolation theory applied to measures of fragmentation in social networks

We apply percolation theory to a recently proposed measure of fragmentation $F$ for social networks. The measure $F$ is defined as the ratio between the number of pairs of nodes that are not connected in the fragmented network after removing a fraction $q$ of nodes and the total number of pairs in the original fully connected network. We compare $F$ with the traditional measure used in percolation theory, $P_{\infty}$, the fraction of nodes in the largest cluster relative to the total number of nodes. Using both analytical and numerical methods from percolation, we study Erd\H{o}s-R\'{e}nyi (ER) and scale-free (SF) networks under various types of node removal strategies. The removal strategies are: random removal, high degree removal and high betweenness centrality removal. We find that for a network obtained after removal (all strategies) of a fraction $q$ of nodes above percolation threshold, $P_{\infty}\approx (1-F)^{1/2}$. For fixed $P_{\infty}$ and close to percolation threshold ($q=q_c$), we show that $1-F$ better reflects the actual fragmentation. Close to $q_c$, for a given $P_{\infty}$, $1-F$ has a broad distribution and it is thus possible to improve the fragmentation of the network. We also study and compare the fragmentation measure $F$ and the percolation measure $P_{\infty}$ for a real social network of workplaces linked by the households of the employees and find similar results.Comment: submitted to PR

Diazoxide-responsive hyperinsulinemic hypoglycemia caused by HNF4A gene mutations

Objective: The phenotype associated with heterozygous HNF4A gene mutations has recently been extended to include diazoxide responsive neonatal hypoglycemia in addition to maturity-onset diabetes of the young (MODY). To date, mutation screening has been limited to patients with a family history consistent with MODY. In this study, we investigated the prevalence of HNF4A mutations in a large cohort of patients with diazoxide responsive hyperinsulinemic hypoglycemia (HH). Subjects and methods: We sequenced the ABCC8, KCNJ11, GCK, GLUD1, and/or HNF4A genes in 220 patients with HH responsive to diazoxide. The order of genetic testing was dependent upon the clinical phenotype. Results: A genetic diagnosis was possible for 59/220 (27%) patients. KATP channel mutations were most common (15%) followed by GLUD1 mutations causing hyperinsulinism with hyperammonemia (5.9%), and HNF4A mutations (5%). Seven of the 11 probands with a heterozygous HNF4A mutation did not have a parent affected with diabetes, and four de novo mutations were confirmed. These patients were diagnosed with HI within the first week of life (median age 1 day), and they had increased birth weight (median +2.4 SDS). The duration of diazoxide treatment ranged from 3 months to ongoing at 8 years. Conclusions: In this large series, HNF4A mutations are the third most common cause of diazoxide responsive HH. We recommend that HNF4A sequencing is considered in all patients with diazoxide responsive HH diagnosed in the first week of life irrespective of a family history of diabetes, once KATP channel mutations have been excluded

Network Topology of an Experimental Futures Exchange

Many systems of different nature exhibit scale free behaviors. Economic systems with power law distribution in the wealth is one of the examples. To better understand the working behind the complexity, we undertook an empirical study measuring the interactions between market participants. A Web server was setup to administer the exchange of futures contracts whose liquidation prices were coupled to event outcomes. After free registration, participants started trading to compete for the money prizes upon maturity of the futures contracts at the end of the experiment. The evolving `cash' flow network was reconstructed from the transactions between players. We show that the network topology is hierarchical, disassortative and scale-free with a power law exponent of 1.02+-0.09 in the degree distribution. The small-world property emerged early in the experiment while the number of participants was still small. We also show power law distributions of the net incomes and inter-transaction time intervals. Big winners and losers are associated with high degree, high betweenness centrality, low clustering coefficient and low degree-correlation. We identify communities in the network as groups of the like-minded. The distribution of the community sizes is shown to be power-law distributed with an exponent of 1.19+-0.16.Comment: 6 pages, 12 figure