Anatomical characteristics and hydrologic signals in tree-rings of oaks (Quercus robur L.)

Q. robur decline in European floodplain forests in recent years seems to be strongly associated with the deteriorating hydrological regime. We investigated the influence of the Krka River flow on tree-ring patterns of Q. robur from the Krakovo floodplain forests (Slovenia) to assess the effect of micro-location conditions on hydrological signals in wood-anatomical characteristics. We selected two groups of Q. robur trees growing at nearby locations with different hydrological conditions, resulting in frequent autumn and spring flooding at the wetter site (=W oaks) but no flooding at the other, drier site (=D oaks). We found differences between the two groups in the anatomical structure of tree-rings; however, ring width proved to be the main variable determining the anatomical structure of oak wood. D and W oaks responded differently to the Krka River flow in the studied period. Radial growth of D oaks was negatively influenced by spring flow, but positively influenced by minimum summer flow. In W oaks, ring width was positively correlated with mean summer flow. Thus, environmental information stored in wood-anatomical features may vary, even within the same forest stand, and largely depends on the micro-environment. Reduced wood increments of D oaks suggest that growth conditions are less favourable, implying a link between the health state of oaks from lowland forest and hydrological conditions. Trees intended for hydrological reconstruction must therefore be carefully selected to avoid the possibility of error and potential loss of information. Anatomical characteristics and hydrological signals in tree-rings of oaks from areas with regular flooding may vary, even within the same forest stand, and largely depends on the micro-environmental conditions

Impact of sociodemographic factors and previous interactions with the health care system on institutional trust in three racial/ethnic groups

OBJECTIVE: Our objective was to explore whether there are differences in institutional trust across racial/ethnic groups and what factors might contribute to these differences. METHODS: We studied a convenience sample of 569 adults in Chicago grocery stores who self-identified as African American, Mexican-Hispanic, or white. We measured institutional trust and dichotomized responses into “high” and “low” trust. We used chi squared tests to examine differences in institutional trust across racial/ethnic groups and stepwise multivariable logistic regression to investigate how sociodemographic factors, health care access, health care usage, and previous negative experience with the health care system modified this relationship. RESULTS: In unadjusted analysis, race/ethnicity was significantly associated with institutional trust (p<0.001). In the fully adjusted model, African Americans and Mexican-Hispanics had greater odds of reporting low trust compared to whites (OR:1.90; 95%CI,1.13–3.17; and OR:2.34; 95%CI,1.43–3.81, respectively); reporting a previous negative health care experience was the only other factor significantly related to having low trust (OR:2.84; 95%CI,1.83–4.41). CONCLUSIONS: We found lower institutional trust in African Americans and Mexican-Hispanics and among participants reporting previous negative health care experiences. PRACTICE IMPLICATIONS: Improving health care experiences, especially for racial/ethnic minority groups, could improve institutional trust and decrease health disparities in these populations

Imidazo[1,2-b]pyridazines and an imidazo[l,2-a]pyrazine from pyridazin- and pyrazin-amines

The ambiguous condensations of phenylglyoxal with pyridazin-3-amines and pyrazin-2-amine are shown to yield 2-phenylimidazo[l,2-b]pyridazin-3(5H)-ones and imidazo[1,2-a]pyrazin-3(7H)-one, respectively. The former products exist as such, at least in the solid state, whereas the latter product exists to a large extent as the corresponding dipolar molecule. The reactions, degradations and n.m.r. spectra of the products are discussed.</jats:p