2,009 research outputs found

    Education and Intergenerational Mobility: Evidence from a Natural Experiment in Purerto Rico

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    The existence of intergenerational spillovers to public investments in schooling is often assumed in policy discussions regarding economic development. However, few studies to date have forwarded convincing evidence that externalities exist for developing countries. In this paper, we address this issue using the arguably exogenous schooling consequences of a major hurricane strike on Puerto Rico in the 1950s. Using data from the US. Census of Population for Puerto Rico, we first find that individuals on to margin of school entry at the time of the storm and residing in the most exposed regions of the island had significantly lower levels of education as adults than their counterparts in less exposed regions. Using the interaction of wind speed and age at the time of the storm as an instrument, we then find that maternal education is related to the probability that a child speaks English. Our estimates imply an additional year of education raise the probability that a child speaks English by between 4.3 and 4.5 percentage points, c approximately 24 to 28 percent. We find no conclusive evidence that parental education increases the probability that a child is enrolled, literate, or in an age-appropriate grad, On balance, these findings suggest that education is responsible at least in part for the persistence of human capital across generations.education, intergenerational mobility, natural experiment, hurricane

    DNA Sequence Determinants Controlling Affinity, Stability and Shape of DNA Complexes Bound by the Nucleoid Protein Fis.

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    The abundant Fis nucleoid protein selectively binds poorly related DNA sequences with high affinities to regulate diverse DNA reactions. Fis binds DNA primarily through DNA backbone contacts and selects target sites by reading conformational properties of DNA sequences, most prominently intrinsic minor groove widths. High-affinity binding requires Fis-stabilized DNA conformational changes that vary depending on DNA sequence. In order to better understand the molecular basis for high affinity site recognition, we analyzed the effects of DNA sequence within and flanking the core Fis binding site on binding affinity and DNA structure. X-ray crystal structures of Fis-DNA complexes containing variable sequences in the noncontacted center of the binding site or variations within the major groove interfaces show that the DNA can adapt to the Fis dimer surface asymmetrically. We show that the presence and position of pyrimidine-purine base steps within the major groove interfaces affect both local DNA bending and minor groove compression to modulate affinities and lifetimes of Fis-DNA complexes. Sequences flanking the core binding site also modulate complex affinities, lifetimes, and the degree of local and global Fis-induced DNA bending. In particular, a G immediately upstream of the 15 bp core sequence inhibits binding and bending, and A-tracts within the flanking base pairs increase both complex lifetimes and global DNA curvatures. Taken together, our observations support a revised DNA motif specifying high-affinity Fis binding and highlight the range of conformations that Fis-bound DNA can adopt. The affinities and DNA conformations of individual Fis-DNA complexes are likely to be tailored to their context-specific biological functions

    Idea Exchange

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    Macrolides in the treatment of children with Mediterranean spotted fever

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    Till now there is not a gold standard therapy for Mediterranean spotted fever (MSF) in children. Standard treatment for MSF is the administration of tetracycline or chloramphenicol, however both these drugs can cause significant adverse effects in children (tetracyclines can cause staining of teeth, chloramphenicol severe hematological adverse events such as aplastic anemia, gray baby syndrome and hemolytic anemia in patients with the Mediterranean form of G6PD deficiency). We conducted two randomized clinical trials; the first compared clarithromycin versus chloramphenicol: mean time to defervescence was 36.7 +/- 18.1 h in the clarithromycin group and 47.1+/- 21.9 h in the chloramphenicol group (P= 0.047). The second trial compared clarithromycin versus azithromycin and did not show any statistically significant difference: mean time to defervescence was 46.2 +/- 36.4 h in the clarithromycin group and 39.3 +/- 31.3 h in the azithromycin group (P= 0.34). On the basis of these studies we think that clarithromycin and azithromycin could constitute an acceptable alternative to chloramphenicol and to tetracyclines for the treatment of MSF in childre

    Childhood Mediterranean visceral leishmaniasis

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    Visceral leishmaniasis (VL) is endemic in areas bordering the Mediterranean Sea (Spain, Italy, France, Greece, Morocco, Tunisia) where it is caused by Leishmania infantum and it is transmitted by the bite of hematophagous sandfly belonging to Phlebotomus spp.; dog constitutes the main reservoir of the infection. In comparison with the past, when VL was typically observed more frequently in children, the current ratio of childhood to adult cases is approximately 1:1. The onset of the disease is characterized by a non-specific initial symptomatology; fever, pallor and splenomegaly are always present. Pancytopenia is present very often; the laboratory diagnosis is established by serological tests (indirect fluorescent-antibody assay, immunoassay test, indirect hemagglutination assay) and by demonstration of Leishmania parasites by microscopy, culture or polymerase chain reaction (PCR) in the bone marrow aspirates. The use of PCR performed on peripheral blood has been reported to be highly sensitive for the diagnosis and the follow up of children with VL. Pentavalent antimonial drugs have been used for many decades as standard treatment for VL; in Italy liposomal amphotericin B (AmBisome) is nowadays considered the first-line treatment for V

    Yeast Irc6p is a novel type of conserved clathrin coat accessory factor related to small G proteins.

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    Clathrin coat accessory proteins play key roles in transport mediated by clathrin-coated vesicles. Yeast Irc6p and the related mammalian p34 are putative clathrin accessory proteins that interact with clathrin adaptor complexes. We present evidence that Irc6p functions in clathrin-mediated traffic between the trans-Golgi network and endosomes, linking clathrin adaptor complex AP-1 and the Rab GTPase Ypt31p. The crystal structure of the Irc6p N-terminal domain revealed a G-protein fold most related to small G proteins of the Rab and Arf families. However, Irc6p lacks G-protein signature motifs and high-affinity GTP binding. Also, mutant Irc6p lacking candidate GTP-binding residues retained function. Mammalian p34 rescued growth defects in irc6 cells, indicating functional conservation, and modeling predicted a similar N-terminal fold in p34. Irc6p and p34 also contain functionally conserved C-terminal regions. Irc6p/p34-related proteins with the same two-part architecture are encoded in genomes of species as diverse as plants and humans. Together these results define Irc6p/p34 as a novel type of conserved clathrin accessory protein and founding members of a new G protein-like family

    Control of DNA minor groove width and Fis protein binding by the purine 2-amino group.

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    The width of the DNA minor groove varies with sequence and can be a major determinant of DNA shape recognition by proteins. For example, the minor groove within the center of the Fis-DNA complex narrows to about half the mean minor groove width of canonical B-form DNA to fit onto the protein surface. G/C base pairs within this segment, which is not contacted by the Fis protein, reduce binding affinities up to 2000-fold over A/T-rich sequences. We show here through multiple X-ray structures and binding properties of Fis-DNA complexes containing base analogs that the 2-amino group on guanine is the primary molecular determinant controlling minor groove widths. Molecular dynamics simulations of free-DNA targets with canonical and modified bases further demonstrate that sequence-dependent narrowing of minor groove widths is modulated almost entirely by the presence of purine 2-amino groups. We also provide evidence that protein-mediated phosphate neutralization facilitates minor groove compression and is particularly important for binding to non-optimally shaped DNA duplexes

    Direct-acting antivirals and visceral leishmaniasis: A case report

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    Background: Visceral leishmaniasis is a vector-borne parasitic disease caused by protozoa belonging to the genus Leishmania. The clinical presentation of visceral leishmaniasis strictly depends on the host immunocompetency, whereas depressive conditions of the immune system impair the capability to resolve the infection and allow reactivation from sites of latency of the parasite. Case presentation: We describe a case of visceral leishmaniasis (VL) that occurred in a patient with chronic hepatitis C treated with direct-acting antiviral drugs (DAA). The hypothesized mechanism is the alteration of protective inflammation mechanisms secondary to DAA therapy. Downregulation of type II and III IFNs, their receptors, which accompany HCV clearance achieved during treatment with sofosbuvir and ribavirin might have a negative impact on a risk for reactivation of a previous Leishmania infection. We know indeed that IFN-\u3b3 is important to enhance killing mechanisms in macrophages, which are the primary target cells of Leishmania. Conclusion: Since VL is endemic in Sicily as well as in other countries of the Mediterranean basin, physicians should be aware of the possible unmasking of cryptic Leishmania infection by DAAs

    Importance of Best Guesses in Emergency Situations

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    During emergency situations, such as natural disasters or the current pandemic, there may not be immediate access to research-based information or information may be nonexistent or conflicting. In such scenarios, Extension personnel may be required to make best guesses based on “what is known so far.” Depending on the urgency of the situation, Extension personnel should draw on opinions and expertise from diverse networks of people and resources before making a best guess. When making a best guess, the Extension professional should follow up to determine whether any information disseminated and recommendations made were correct or not. In either case, the result should be made known

    Fatal delayed diagnosis in a patient with falciparum malaria

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    This is a classical case of blackwater fever which is one of the most serious hematologic complications of falciparum malaria. The clinical manifestations of this acute intravascular hemolityc anemia are fulminating and delayed diagnosis is an important cause of mortality
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