991 resultados para 1:504


Relevância:

60.00% 60.00%

Publicador:

Resumo:

To get a better understanding of mutagenic mechanisms in humans, we have cloned and sequenced the human homolog of the Saccharomyces cerevisiae REV3 gene. The yeast gene encodes the catalytic subunit of DNA polymerase ζ, a nonessential enzyme that is thought to carry out translesion replication and is responsible for virtually all DNA damage-induced mutagenesis and the majority of spontaneous mutagenesis. The human gene encodes an expected protein of 3,130 residues, about twice the size of the yeast protein (1,504 aa). The two proteins are 29% identical in an amino-terminal region of ≈340 residues, 39% identical in a carboxyl-terminal region of ≈850 residues, and 29% identical in a 55-residue region in the middle of the two genes. The sequence of the expected protein strongly predicts that it is the catalytic subunit of a DNA polymerase of the pol ζ type; the carboxyl-terminal domain possesses, in the right order, the six motifs characteristic of eukaryotic DNA polymerases, most closely resembles yeast pol ζ among all polymerases in the GenBank database, and is different from the human α, δ, and ɛ enzymes. Human cells expressing high levels of an hsREV3 antisense RNA fragment grow normally, but show little or no UV-induced mutagenesis and are slightly more sensitive to killing by UV. The human gene therefore appears to carry out a function similar to that of its yeast counterpart.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Background: Strategies to tackle maternal mortality in sub-Saharan Africa include expanding coverage of reproductive services.Even where high, more vulnerable women may not access services. No data is available on high coverage determinants. We investigated this in Tanzania in a predicted high utilization area. Methods: Data was collected through a household survey of 464 women with a recent delivery. Primary outcomes were facility delivery and ≥4 ANC visits. Determinants were analysed using multivariate regression. Results: Almost all women had attended ANC, though only 58.3% had ≥4 visits. ≥4 visits were more likely in the youngest age group (OR 2.7 95% CI 1.32–5.49, p=0.008), and in early ANC attenders (OR 3.2 95% CI 2.04–4.90, p<0.001). Facility delivery was greater than expected (87.7%), more likely in more educated women (OR 2.7 95% CI 1.50–4.75, p=0.002), in those within 5 kilometers of a facility (OR 3.2 95% CI 1.59–6.48, p=0.002), and for early ANC attenders (OR 2.4 95% CI 1.20–4.91, p=0.02). Conclusion: Rural contexts can achieve high facility delivery coverage. Based on our findings, strategies to reach women yet unserved should include promotion of early ANC start particularly for the less educated, and improvement of distant communities' access to facilities.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The aim of this study is to determine which social agents are involved in the political debate on Twitter and whether the interpretive hegemony of actors that have traditionally been the most prominent is tempered by the challenge of framing shared with audiences. The relationship between the interpretations expressed and the profiles of participants is analyzed in comparison with the frames used by mainstream media. The chosen methodology combines content analysis and discourse analysis techniques on a sample of 1,504 relevant tweets posted on two political issues –the approval of the education law LOMCE and the evictions caused by the crisis, which have also been studied in the front pages of four leading newspapers in Spain. The results show a correlation between political issue singularities, frames and the type of discussion depending on the participants.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Objective: Given the inaccessibility of indirect calorimetry, intensive care units generally use predictive equations or recommendations that are established by international societies to determine energy expenditure. The aim of the present study was to compare the energy expenditure of critically ill patients, as determined using indirect calorimetry, to the values obtained using the Harris-Benedict equation. Methods: A retrospective observational study was conducted at the Intensive Care Unit 1 of the Centro Hospitalar do Porto. The energy requirements of hospitalized critically ill patients as determined using indirect calorimetry were assessed between January 2003 and April 2012. The accuracy (± 10% difference between the measured and estimated values), the mean differences and the limits of agreement were determined for the studied equations. Results: Eighty-five patients were assessed using 288 indirect calorimetry measurements. The following energy requirement values were obtained for the different methods: 1,753.98±391.13 kcal/ day (24.48 ± 5.95 kcal/kg/day) for indirect calorimetry and 1,504.11 ± 266.99 kcal/day (20.72±2.43 kcal/kg/day) for the HarrisBenedict equation. The equation had a precision of 31.76% with a mean difference of -259.86 kcal/day and limits of agreement between -858.84 and 339.12 kcal/day. Sex (p=0.023), temperature (p=0.009) and body mass index (p< 0.001) were found to significantly affect energy expenditure Conclusion: The Harris-Benedict equation is inaccurate and tends to underestimate energy expenditure. In addition, the Harris-Benedict equation is associated with significant differences between the predicted and true energy expenditure at an individual level

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Briefwechsel und Beilagen zwischen Max Horkheimer, Theodor W. Adorno und Gretel Adorno, 1942 - 1944; 1 Brief von Friedrich Pollock an Theodor W. Adorno, 1942; 1 Brief von Theodor W. Adorno an Friedrich Pollock, 1944; 1 Brief von Else Frenkel-Brunswick an Theodor W. Adorno, 1944; 1 Brief von Max Horkheimer an das American Jewish Commitee, 1944; Briefwechsel und Beilagen zwischen Gretel Adorno, Theodor W. Adorno und Frederick Wild, 1942 - 1944; 1 Brief von Gretel Adorno an Leo Löwenthal, 1944; 1 Brief von Monroe E. Deutsch an Theodor W. Adorno, 1944; Briefwechsel zwischen Theodor W. Adorno und Margot von Mendelssohn, 1942 - 1943; 1 Brief von der Bank of America in Los Angeles an Frederick Wild, 1942;

Relevância:

40.00% 40.00%

Publicador:

Resumo:

We discuss the provenance of minerals detected by X-ray-diffraction analyses of sediments of Sites 504 and 505 of Deep Sea Drilling Project Leg 69. These are X-ray-amorphous material, opal-CT, calcite, quartz, feldspar, apatite, smectite, illite, kaolinite, magnetite, maghemite, pyrite, marcasite, barite, sepiolite, and clinoptilolite. Authigenic marcasite and clinoptilolite together with opal-CT are restricted to Site 504, indicating the special diagenetic conditions related to relatively high sediment temperatures at this site. Marcasite formation is likely dependent on the relatively low pH values of <7.1 found in interstitial waters of Site 504 sediments below 50 meters sub-bottom. Clinoptilolite evidently was formed by diagenetic alteration of rhyolitic volcanic glass or smectite plus biogenic silica within the chalk-limestone-chert sequence of Site 504, where opal-CT also reflects a high degree of silica dissolution and reprecipitation. This was a consequence of high temperatures (50-55 °C) at the base of the sediment column.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

A standard biostratigraphic system, based upon diatom datum levels previously correlated to the paleomagnetic record, was applied to Deep Sea Drilling Project Sites 501/504 and 505. Sedimentation appears to have been constant at the three sites, averaging 50 m/m.y. at Sites 501/504 and 60 m/m.y. at Site 505. Calcium carbonate is rather poorly preserved at both sites, because of depth of water and, at Sites 501/504, alteration by diagenesis. Siliceous microfossils are common and moderately well preserved at the three sites; at Sites 501/504, diatoms disappear abruptly below the first occurrence of chert. The uppermost Miocene diatom assemblage occurs just above chert and is characterized by a strong dominance of Thalassionema and Thalassiothrix, which implies very high silica production during the latest Miocene; the chert probably is derived from a similar assemblage. In the earliest Pliocene, silica production appears to have decreased sharply; about 3 Ma, preservation of calcium carbonate also diminished, suggesting a shoaling of the CCD. At 2 Ma, there occurred a short interval of low production of both calcium carbonate and silica, which lasted into the earliest Pleistocene.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Values of physical properties measured in the upper sections of sediment cores recovered at Sites 504 and 505 exhibit a remarkable similarity. Below a depth of 145 m Site 504 sediments appear to have undergone changes which are reflected in physical property values. This alteration may have been due to high temperatures in the sediment. In most of Site 505, and in Site 504 above 145 m, seismic velocity averages 1.51 km/s, wet bulk density 1.32 g/cm**3, porosity 80%, and thermal conductivity 0.80% W/m °K. Below 145 m at Site 504 and 210 m at Site 505, mean density increases to 1.40 g/cm**3, porosity decreases to 67%, seismic velocity increases to 1.53 km/s, and thermal conductivity increases to values in excess of 1.0 W/m °K. A good correlation between independent measurements of water content and thermal resistivity supports the existence of small but regular variation in the measured parameters on the scale of 10 m and less.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Diverse and abundant late Miocene to Pleistocene silicoflagellates at DSDP Site 504 can be correlated by tropical biostratigraphic zones and relative paleotemperature values to eastern tropical Pacific reference site DSDP 503A farther to the west. Early Pliocene assemblages, which were poorly known until now, are present and can be correlated locally between DSDP Holes 504, 503A, and 495, using species events associated with the new Dictyocha pulchella Subzone and Dictyocha angulata Subzone. Silicoflagellate relative paleotemperature values show major warming at 4.7 to 5.0 Ma (Cores 45-48), 3.4 to 3.8 Ma (Cores 32-33), 1.5 to 1.7 Ma (Cores 12-16), and 0.5 to 0.8 Ma (Cores 3-6). Major coolings occurred at 5.0 to 5.1 Ma (Core 51), 3.9 to 4.4 Ma (Cores 38-44), and 1.0 to 1.3 Ma (Cores 8-10). The appearance of Dictyocha longa is proposed to replace the asperoid/fibuloid ratio reversal as the bottom of the Dictyocha fibula Zone, because the non-evolutionary ratio reverses several times in the upper Miocene of Hole 503A, and at least once in Hole 504. Three new Pliocene silicoflagellates are defined: Dictyocha concinna Bukry, n. sp., D. helix Bukry, n. sp., and D. tamarae Bukry, n. sp.