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ObjectivesWe previously reported that random assignment of scientific articles to a social media exposure intervention did not have an effect on article downloads and citations. In this paper, we investigate whether longer observation time after exposure to a social media intervention has altered the previously reported results.MethodsFor articles published in the International Journal of Public Health between December 2012 and December 2014, we updated article download and citation data for a minimum of 24-month follow-up. We re-analysed the effect of social media exposure on article downloads and citations.ResultsThere was no difference between intervention and control group in terms of downloads (p = 0.72) and citations (p= 0.30) for all papers and when we stratified by open access status.ConclusionsLonger observation time did not increase the relative differences in the numbers of downloads and citations between papers in the social media intervention group and papers in the control group. Traditional impact metrics based on citations, such as impact factor, may not capture the added value of social media for scientific publications.

Zusammenfassung. Psychische Erkrankungen in der Schwangerschaft und im ersten Jahr nach einer Geburt können schwerwiegende negative Folgen haben, wenn sie nicht behandelt werden. Wir wissen jedoch bisher kaum etwas über die Gesundheitsversorgung betroffener Frauen. Dieser Aufsatz beleuchtet aktuelle Daten zur Epidemiologie perinataler psychischer Erkrankungen, zeigt die Defizite der aktuellen Versorgung sowie die notwendigen Schritte zum Schliessen der Lücken im Bereich der Ausbildung und Forschung auf.

We sought to investigate whether exposing scientific papers to social media (SM) has an effect on article downloads and citations. We randomized all International Journal of Public Health (IJPH) original articles published between December 2012 and December 2014 to SM exposure (blog post, Twitter and Facebook) or no exposure at three different time points after first online publication. 130 papers (SM exposure = 65, control = 65) were randomized. The number of downloads did not differ significantly between groups (p = 0.60) nor did the number of citations (p = 0.88). Adjusting for length of observation and paper’s geographical origin did not change these results. There was no difference in the number of downloads and citations between the SM exposure and control group when we stratified for open access status. The number of downloads and number of citations were significantly correlated in both groups. SM exposure did not have a significant effect on traditional impact metrics, such as downloads and citations. However, other metrics may measure the added value that social media might offer to a scientific journal, such as wider dissemination.

It is our great pleasure to publish this special issue with reviews relevant to global health. IJPH launched this Call to concert the 9th European Congress on Tropical Medicine and International Health, which runs under the title ‘‘Driving the Best Science to Meet Global Health Challenges’’. The Call received high attention with 18 manuscripts submitted from 11 countries in the Americas, Europe and Asia. Although half of the submitted reviews addressed problems in low-income or developing countries, no authors from Africa responded to the Call. Does this reflect the continued inequity in the availability of research resources for global health? To manage the rigorous peer review process, we were again largely dependent on our highly committed international reviewers, greatly acknowledged in Table 1. Given the topic of the Call, we tried our best to involve experts from across the world as peer reviewers and received reports from 37 experts from 16 countries, though the majority of peer reviewers is based in USA or Canada (13), or in Europe (12). Nine reviews were finally accepted for publication. The special issue now presents an interesting range of reviews, as the contributing authors bring to our focus infectious diseases, maternal and child health, and finally physical and mental health. Repeating the major success of the IJPH Call launched in 2013 (Kunzli 2013), we have again asked the audience of the conference to choose the most interesting review based on a set of four abstracts that we considered to represent the most relevant reviews that were accepted for publication. The four publications reviewed topics on equity in maternal health care service utilization, knowledge transfer strategies to improve public health in lowincome countries, injury and rehabilitation interventions in humanitarian crises and concerns on vaccination use in lowand middle-income countries. Reducing maternal mortality is one of the Millennium Development Goals (MDGs) and in the post-2015 era, it will remain an important agenda to be pursued amidst the achievement of the Sustainable Development Goals (SDGs). A systematic review by Caliskan et al. (2015) found a lack of equity in the utilization of maternal health care in developing countries, and directed our attention to not only improving maternal care but more importantly, ensuring that even the most disadvantaged mothers have equal access to the improved care. This is an important This editorial is part of the special issue ‘‘Driving the Best Science to Meet Global Health Challenges’’ edited on the occasion of the 9th European Congress on Tropical Medicine and International Health 2015.

We used a Scholander pressure chamber to assess the effects of various extraction methods under different environmental conditions on element concentrations in xylem sap of 3-year-old Picea abies (L.) Karst. seedlings. Sap from excised shoots contained higher element concentrations when extracted at low than at high over-pressures. When comparing plants differing in water status, we found that a high extraction over-pressure introduced a systematic error into the data. For example, in well-watered non-transpiring plants relative to unwatered transpiring plants, potassium concentrations were 70% higher in sap extracted at 0.1 MPa over-pressure, but only 10% higher in sap extracted at 1.0 MPa over-pressure. Moreover, treatment effects depended on the time of day when the sap was extracted. Increased water flux in transpiring plants relative to non-transpiring plants resulted in reduced xylem sap element concentrations when samples were collected after 9 h of transpiration, but not after 4 to 6 h of transpiration. Drought had little effect on xylem sap element concentrations, indicating that rates of element release into xylem conduits, element depletion by growing tissues, and water flow maintained a balance that may prevent nutrient stress during short-term drought.

Ring-opening cross metathesis reaction of norbornene derivatives with styrene derivatives proceeds smoothly in the presence of a novel Ru catalyst.

The mammalian genome is organized as a mosaic of isochores, stretches of DNA with a distinct sequence composition. Isochores form the basis of the chromosomal banding pattern, which is tightly correlated with a number of structural and functional features. We have recently demonstrated that the transition from a GC-poor isochore to a GC-rich one in the NF1 gene region occurs within 5 kb and demarcates genomic regions with high and low recombination frequency. We now report that the same transition zone separates early replicating from late replicating chromatin on the molecular level. At the isochore transition the replication fork is stalled in mid-S phase and can be visualized by fiber-FISH techniques as a Y-shaped structure. The switch in GC content and in replication timing is conserved between human and mouse, emphasizing the importance of the transition zones as landmarks of chromosome organization and function.