Herstellen van akkers als onderdeel van een intact heidelandschap : de koppeling tussen arme heidegebieden en rijkere gronden

De heidegebieden in Nederland herbergen een groot aantal habitattypen die in Europees opzicht erg waardevol zijn. Voorbeelden zijn droge en vochtige heide (H4030 en H4010), zandverstuivingen (H2330) en zwakgebufferde vennen (H3130). Deze heidegebieden liggen temidden van intensief gebruikt agrarisch gebied. Rechtstreeks gevolg hiervan lijkt dat karakteristieke faunasoorten van heidelandschappen nog steeds achteruit gaan in verspreiding. Een groeiend aantal beheerders experimenteert tegenwoordig met tijdelijke beakkering van kleine perceeltjes in of direct grenzend aan heideterreinen, met als doel de aan het heidelandschap verbonden diersoorten een grotere overlevingskans te geven. Daarnaast bestaan er bij beheerders vragen over het gewenste beheer van bestaande (extensieve) landbouwpercelen en wildakkers ten behoeve van de versterking van de natuurwaarden in nabij gelegen heidegebiede

Cyberbullying: a storm in a teacup?

Cyberbullying has been portrayed as a rising ‘epidemic’ amongst children and adolescents. But does it create many new victims beyond those already bullied with traditional means (physical, relational)? Our aim was to determine whether cyberbullying creates uniquely new victims, and whether it has similar impact upon psychological and behavioral outcomes for adolescents, beyond those experienced by traditional victims. This study assessed 2745 pupils, aged 11–16, from UK secondary schools. Pupils completed an electronic survey that measured bullying involvement, self-esteem and behavioral problems. Twenty-nine percent reported being bullied but only 1% of adolescents were pure cyber-victims (i.e., not also bullied traditionally). Compared to direct or relational victims, cyber-victimization had similar negative effects on behavior (z = −0.41) and self-esteem (z = −0.22) compared to those not involved in bullying. However, those bullied by multiple means (poly-victims) had the most difficulties with behavior (z = −0.94) and lowest self-esteem (z = −0.78). Cyberbullying creates few new victims, but is mainly a new tool to harm victims already bullied by traditional means. Cyberbullying extends the reach of bullying beyond the school gate. Intervention strategies against cyberbullying may need to include approaches against traditional bullying and its root causes to be successful.Published versio

Innate Immune Function in Placenta and Cord Blood of Hepatitis C – Seropositive Mother-Infant Dyads

Vertical transmission accounts for the majority of pediatric cases of hepatitis C viral (HCV) infection. In contrast to the adult population who develop persistent viremia in ∼80% of cases following exposure, the rate of mother-to-child transmission (2–6%) is strikingly low. Protection from vertical transmission likely requires the coordination of multiple components of the immune system. Placenta and decidua provide a direct connection between mother and infant. We hypothesized that innate immune responses would differ across the three compartments (decidua, placenta and cord blood) and that hepatitis C exposure would modify innate immunity in these tissues. The study was comprised of HCV-infected and healthy control mother and infant pairs from whom cord blood, placenta and decidua were collected with isolation of mononuclear cells. Multiparameter flow cytometry was performed to assess the phenotype, intracellular cytokine production and cytotoxicity of the cells. In keeping with a model where the maternal-fetal interface provides antiviral protection, we found a gradient in proportional frequencies of NKT and γδ-T cells being higher in placenta than cord blood. Cytotoxicity of NK and NKT cells was enhanced in placenta and placental NKT cytotoxicity was further increased by HCV infection. HCV exposure had multiple effects on innate cells including a decrease in activation markers (CD69, TRAIL and NKp44) on NK cells and a decrease in plasmacytoid dendritic cells in both placenta and cord blood of exposed infants. In summary, the placenta represents an active innate immunological organ that provides antiviral protection against HCV transmission in the majority of cases; the increased incidence in preterm labor previously described in HCV-seropositive mothers may be related to enhanced cytotoxicity of NKT cells

Longitudinal immune monitoring of patients with resectable esophageal adenocarcinoma treated with Neoadjuvant PD-L1 checkpoint inhibition

The analysis of peripheral blood mononuclear cells (PBMCs) by flow cytometry holds promise as a platform for immune checkpoint inhibition (ICI) biomarker identification. Our aim was to characterize the systemic immune compartment in resectable esophageal adenocarcinoma patients treated with neoadjuvant ICI therapy. In total, 24 patients treated with neoadjuvant chemoradiotherapy (nCRT) and anti-PD-L1 (atezolizumab) from the PERFECT study (NCT03087864) were included and 26 patients from a previously published nCRT cohort. Blood samples were collected at baseline, on-treatment, before and after surgery. Response groups for comparison were defined as pathological complete responders (pCR) or patients with pathological residual disease (non-pCR). Based on multicolor flow cytometry of PBMCs, an immunosuppressive phenotype was observed in the non-pCR group of the PERFECT cohort, characterized by a higher percentage of regulatory T cells (Tregs), intermediate monocytes, and a lower percentage of type-2 conventional dendritic cells. A further increase in activated Tregs was observed in non-pCR patients on-treatment. These findings were not associated with a poor response in the nCRT cohort. At baseline, immunosuppressive cytokines were elevated in the non-pCR group of the PERFECT study. The suppressive subsets correlated at baseline with a Wnt/β-Catenin gene expression signature and on-treatment with epithelial-mesenchymal transition and angiogenesis signatures from tumor biopsies. After surgery monocyte activation (CD40), low CD8+Ki67+ T cell rates, and the enrichment of CD206+ monocytes were related to early recurrence. These findings highlight systemic barriers to effective ICI and the need for optimized treatment regimens

A Search for Technosignatures Around 11,680 Stars with the Green Bank Telescope at 1.15-1.73 GHz

We conducted a search for narrowband radio signals over four observing sessions in 2020-2023 with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. We pointed the telescope in the directions of 62 TESS Objects of Interest, capturing radio emissions from a total of ~11,680 stars and planetary systems in the ~9 arcminute beam of the telescope. All detections were either automatically rejected or visually inspected and confirmed to be of anthropogenic nature. In this work, we also quantified the end-to-end efficiency of radio SETI pipelines with a signal injection and recovery analysis. The UCLA SETI pipeline recovers 94.0% of the injected signals over the usable frequency range of the receiver and 98.7% of the injections when regions of dense RFI are excluded. In another pipeline that uses incoherent sums of 51 consecutive spectra, the recovery rate is ~15 times smaller at ~6%. The pipeline efficiency affects calculations of transmitter prevalence and SETI search volume. Accordingly, we developed an improved Drake Figure of Merit and a formalism to place upper limits on transmitter prevalence that take the pipeline efficiency and transmitter duty cycle into account. Based on our observations, we can state at the 95% confidence level that fewer than 6.6% of stars within 100 pc host a transmitter that is detectable in our search (EIRP > 1e13 W). For stars within 20,000 ly, the fraction of stars with detectable transmitters (EIRP > 5e16 W) is at most 3e-4. Finally, we showed that the UCLA SETI pipeline natively detects the signals detected with AI techniques by Ma et al. (2023).Comment: 22 pages, 9 figures, submitted to AJ, revise

Comparing early adolescents’ positive bystander responses to cyberbullying and traditional bullying: the impact of severity and gender

Young people are frequently exposed to bullying events in the offline and online domain. Witnesses to these incidents act as bystanders and play a pivotal role in reducing or encouraging bullying behaviour. The present study examined 868 (47.2% female) 11-13-year-old early adolescent pupils’ bystander responses across a series of hypothetical vignettes based on traditional and cyberbullying events. The vignettes experimentally controlled for severity across mild, moderate, and severe scenarios. The findings showed positive bystander responses (PBRs) were higher in cyberbullying than traditional bullying incidents. Bullying severity impacted on PBRs, in that PBRs increased across mild, moderate, and severe incidents, consistent across traditional and cyberbullying. Females exhibited more PBRs across both types of bullying. Findings are discussed in relation to practical applications within the school. Strategies to encourage PBRs to all forms of bullying should be at the forefront of bullying intervention methods

Protease-activated receptors in diabetic nephropathy and renal fibrosis

In the Netherlands, 1.700.000 people suffer from chronic kidney disease, a condition in which fibrotic tissue builds up in the kidneys. Independent of the underlying cause, chronic kidney disease will slowly progress to end stage renal disease. At that stage, renal replacement therapy by dialysis or transplantation are the only therapeutic options left, which both have a huge social and economic impact. Alternative clinical strategies to prevent the progression of chronic kidney disease are thus eagerly awaited for. As protease-activated receptors recently emerged as key players in fibrosis, the aim of this thesis was to investigate whether protease activated receptors would be good targets for novel interventions that prevent the decay of kidney function in diabetic patients. As described in this thesis, we found that PAR-1 deficiency protected both diabetic mice and mice suffering from chronic obstructive nephropathy from developing diabetic nephropathy and renal fibrosis, whereas PAR-2 rather acted as a double edged sword resulting in both beneficial and detrimental effects. Based on these results we treated both type 1 and type 2 diabetic mice with the PAR-1 inhibitor vorapaxar. Overall, vorapaxar treatment might be a feasible treatment for type 1 diabetic patients at risk for developing diabetic nephropathy. However, this treatment would be feasible only if bleeding complications associated with vorapaxar treatment are not too severe. Finding the endogenous PAR-1 ligand that potentiates diabetic nephropathy may eventually lead to a treatment strategy that limits diabetic nephropathy without the risk of severe bleedings