Early season weed control in maize, new insights for a known phenomenon

The studies demonstrate the effect of early weed control on maize yields compared to late weed control with corresponding herbicide control strategies. Maize yield with a late weed control strategy was 10 % lower compared to a strategy controlling weeds early based on ten field trials. Interestingly the thousand-grainweight (TGW) seems not to be affected significantly but the number of grains per cob were identified as major responsible factor for yield decrease. To explain these field effects, glasshouse test were undertaken to simulate the competitive weed effects. Specific methods allowed to grow maize plants to the yield stage even in the glasshouse under representative conditions. The field observations were confirmed clearly. The early yield parameters like number of grains per cob were mainly affected by the timing of weed control treatments (early vs. late), while the parameter grain rows per cob was more sensible than the number of grains per row. The TGW remained basically consistent. As a follow-up experiment, maize plants were grown under glasshouse conditions and as well grown to the yield stage. This time, subsamples were taken and the cob formation at very early stages was investigated destructively to follow the development of the cob formation. Ovules and rows were counted on 'mini cobs' (cobs with a size of 4 mm were harvested) under the binocular. Clearly, weed competition had an impact on the induction of the number of ovules early on and at the end impacted on the yield in ripe cobs. Keywords: Herbicide, yield, yield parameter, Zea mays L.Frühe Unkrautkontrolle in Mais, neue Erkenntnisse zu einem bekannten PhänomenDie vorliegenden Studien belegen die Wirkung der frühen Unkrautbekämpfung in Mais auf den Ertrag im Vergleich zu später Unkrautbekämpfung mit entsprechenden Herbizid-Bekämpfungs-strategien. Der Maisertrag mit einer späten Unkrautbekämpfungsstrategie war 10 % niedriger im Vergleich zu einer frühen Unkrautbekämpfungsstrategie. Diese Angaben basieren auf zehn Feldversuchen. Interessanterweise scheint das Tausendkorngewicht (TKG) nicht erheblich betroffen zu sein, aber die Anzahl der Körner pro Kolben wurde als Faktor für die Ertragsminderung identifiziert. Um diese Effekte zu klären, wurden Gewächshaustests durchgeführt, welche kompetitiven Bedingungen simulierten. Dank spezifischer Methoden konnten Maispflanzen selbst im Gewächshaus unter repräsentativen Bedingungen bis zur Kornreife gehalten werden. Die Feldbeobachtungen wurden eindeutig bestätigt: Die frühen Ertragsparameter - wie Anzahl der Körner pro Kolben - wurden vor allem durch den Zeitpunkt der Unkrautbekämpfung (früh oder spät) betroffen, wovon die Parameter Reihen pro Kolben stärker reagierten als die Anzahl Körner pro Reihe. Das TKG blieb im Wesentlichen konstant. Als Nachfolge-Experiment wurden wiederum Pflanzen unter Gewächshausbedingungen angezogen und bis zur Ertragsreife angezogen Diesmal wurden destruktiv Stichproben entnommen und die Kolbenbildung in sehr frühen Stadien untersucht. 'Mini-Maiskolben‘ (4 mm Kolbengröße) wurden geerntet und Kornanlagen unter dem Binokular gezählt. Ganz klar konnte auch hier der Einfluss von früher oder später Unkrautkonkurrenz auf die Induktion der Zahl der Samenanlagen festgestellt werden. Stichwörter: Ertrag, Ertragsparameter, Herbizid, Zea mays L

Environmental heterogeneity affects input, storage, and transformation of coarse particulate organic matter in a floodplain mosaic

Quantifying spatial and temporal dynamics of organic matter (OM) is critical both for understanding ecosystem functioning and for predicting impacts of landscape change. To determine the influence of different habitats and coarse particulate OM (CPOM) types upon floodplain OM dynamics, we quantified aerial input, lateral surface transfer, and surface storage of CPOM over an annual cycle on the near-natural floodplain of the River Tagliamento in NE-Italy. Using these data, we modelled floodplain leaf dynamics, taking account of the spatial distribution and hydrologic connectivity of habitats, and using leaf storage as a response variable. Mean aerial CPOM input to the floodplain was similar from riparian forest and islands, but surface transfer was greater from islands, supporting the suggestion that these habitats act as "islands of fertility” along braided rivers. Leaves were the lateral conveyor of energy to more open parts of the floodplain, whereas CPOM was mainly stored as small wood in vegetated islands and riparian forest. Simulating the loss of habitat diversity (islands, ponds) decreased leaf storage on the whole floodplain, on exposed gravel and in large wood accumulations. In contrast, damming (loss of islands, ponds and floods plus floodplain overgrowth) greatly increased storage on exposed gravel. A random shuffle of habitats led to a storage increase on exposed gravel, while that in large wood accumulations and ponds declined. These results disentangle some of the complexities of CPOM dynamics in floodplain ecosystems, illustrate the value of models in understanding ecosystem functioning at a landscape level, and directly inform river management practic

Physicians’ experience with follow-up care of childhood cancer survivors – Challenges and needs

BACKGROUND: Regular follow-up care is essential for childhood cancer survivors, but we know little about physicians’ experience with it. We aimed to describe: (1) involvement of Swiss physicians in follow-up care; (2) content of follow-up care provided; (3) problems encountered; and (4) additional resources needed. MATERIALS AND METHODS: Within this cross-sectional survey we sent adapted questionnaires via professional associations to a sample of medical oncologists (MOs), paediatric oncologists (POs), general practitioners (GPs) and paediatricians (P) in Switzerland. Only oncologists involved in follow-up care were asked to report problems. GPs and Ps not involved in follow-up could indicate why. All physicians were asked about the content of follow-up care provided and additional resources needed. RESULTS: A total of 183 physicians responded (27 MO, 13 PO, 122 GP, 21 P). Involved in follow-up were 81% of MOs, 85% of POs, 39% of GPs and 81% of Ps. Follow-up content differed between oncologists (MO and PO) and generalists (GP and P), with generalists examining or informing less in regard to the former cancer. POs reported more problems than MOs: many POs reported problems with transition of survivors to adult care (91%), and because of financial resources (73%) and time restraints (73%). MOs reported most problems during transition (23%). Not being aware of a survivor was the most common reason for GPs and Ps not participating in followup (74%). All groups reported a need for standardised protocols (85–91%) and specialised training (55–73%). GPs (94%) and Ps (100%) additionally desired more support from oncologists. CONCLUSIONS: To improve quality and efficiency of follow-up care a national follow-up care model including standardised protocols and guidelines needs to be developed

Device-measured physical activity and cardiovascular disease risk in adolescent childhood cancer survivors. A physical activity in childhood cancer survivors (PACCS) study

Objectives: We aimed to compare cardiovascular disease (CVD) risk factors in childhood cancer survivors (CCS) with age- and sex-stratified reference material and examine the association between physical activity (PA) intensities and CVD risk factors in CCS. Materials and methods: Within the cross-sectional, multicenter Physical Activity in Childhood Cancer Survivors (PACCS) study, we collected data on CVD risk factors [VO2-peak (mL⋅kg-1⋅min-1), body mass index (BMI, kg/m2), systolic blood pressure (SBP, mmHg), and total-cholesterol/HDL-cholesterol (Total/HDL)] among CCS aged 9-18 years. CVD risk factors were compared to references with immediate t-tests. We transformed CVD risk factors into z-scores based on international references and generated an individual CVD risk score: [inverse ZVO2-peak + Z BMI + Z SBP + Z Total/HDL )/4]. Multivariable mixed linear regression models were used to analyze the associations between device-measured PA intensities and CVD risk factors. Results: We included 157 CCS aged on average 13.4 years at inclusion and 8.2 years from diagnosis. Male CCS had lower VO2-peak compared to references (45.4 vs. 49.4 mL⋅kg-1⋅min-1, P = 0.001), higher diastolic BP (67 vs. 63 mmHg, P < 0.001), lower HDL (1.35 vs. 1.44 mmol/L, P = 0.012), as well as a tendency to higher CVD risk score (z-score=0.14 vs. 0.00, P = .075). Female CCS' CVD risk factors were comparable to references. Vigorous-intensity PA (VPA) was associated with CVD risk factors. A 10-min increase in VPA was associated with higher VO2-peak (β = 4.9, 95% CI, 2.1-7.7), lower Total/HDL (β = -0.3, 95% CI, -0.6 to -0.1) and a lower CVD risk score (β = -0.4, 95% CI, -0.6 to -0.2). Conclusion: Male adolescent CCS had less favorable values of CVD risk factors compared to references. VPA in adolescent CCS is associated with clinically meaningful favorable values of CVD risk factors. Keywords: accelerometry; cardiometabolic risk; cardiovascular disease risk; childhood cancer survivors; physical activity

Parents' preferences for the organisation of long-term follow-up of childhood cancer survivors

Parents take an important role in follow-up of young cancer survivors. We aimed to investigate (1) parents' preferences for organisation of follow-up (including content, specialists involved and models of care), and (2) parents' and children's characteristics predicting preference for generalist vs. specialist-led follow-up. We sent a questionnaire to parents of childhood cancer survivors aged 11-17 years. We assessed on a 4-point Likert scale (1-4), parents' preferences for organisation of long-term follow-up. Proposed models were: telephone/questionnaire, general practitioner (GP) (both categorised as generalist for regression analysis); and paediatric oncologist, medical oncologist or multidisciplinary team (MDT) (categorised as specialists). Of 284 contacted parents, 189 responded (67%). Parents welcomed if visits included checking for cancer recurrence (mean = 3.89), late effects screening (mean = 3.79), taking patients seriously (mean = 3.86) and competent staff (mean = 3.85). The preferred specialists were paediatric oncologists (mean = 3.73). Parents valued the paediatric oncologist model of care (mean = 3.49) and the MDT model (mean = 3.14) highest. Parents of children not attending clinic-based follow-up (OR = 2.97, p = .009) and those visiting a generalist (OR = 4.23, p = .007) favoured the generalist-led model. Many parents preferred a clinic-based model of follow-up by paediatric oncologists or a MDT. However, parents also valued the follow-up care model according to which their child is followed up