Impacts of alien invasive Parthenium hysterophorus on flower visitation by insects to co-flowering plants

The exotic invasive plant Parthenium hysterophorus is invading many tropical habitats. While much work has been done on its interactions with other native plants, little is known about its interaction with insect floral visitors and how it impacts pre-existing pollination networks when it invades a site. We carried out surveys on sites with and without P. hysterophorus (invaded and uninvaded, respectively) to investigate its impact on plant–pollinator interactions with two common indicator or target plants (Ocimum gratissimum and Ageratum conyzoides) in Tanzania. During multiple 15 min observation periods in quadrats, the number of arriving flower visitors, duration of visits and visitation rate were measured and compared between sites. Visitation networks of flower visitors were developed by observing flower visitor taxonomic groups and plants visited across both invasion categories. Parthenium hysterophorus was heavily visited by a diversity of flies as taxonomic groups. Indicator plants received fewer flower visitors overall in the invaded site, implying P. hysterophorus may be disrupting pollen flow. Foraging behaviour and flower visitation by Apis mellifera and flies on target plants were particularly negatively affected in the invaded quadrats. Flower visitation rate to target plants was significantly lower in invaded quadrats than in uninvaded quadrats. This study supports work in other parts of the world demonstrating that invasive species can strongly disrupt pollination networks. By attracting flower visitors that could otherwise serve as pollinators of native plant species, P. hysterophorus which is rapidly spreading in eastern African ecosystems could have complex deleterious effects on the wider ecosystem

Bio-herbicide potential of naturalised Desmodium uncinatum crude leaf extract against the invasive plant species Parthenium hysterophorus

The exotic plant Parthenium hysterophorus is rapidly invading ecosystems in sub-Saharan Africa, with negative effects on the environment, economy and human and animal health. With the exception of some synthetic herbicides, none of the available management methods have been effective against P. hysterophorus, and carry risks to the environment. Therefore, additional management methods must be explored for an effective integrated approach. Despite the fact that bio-herbicides are considered cost-effective and eco-friendly in mitigating biological invasions, little work has been done to utilize them for controlling P. hysterophorus. We investigated allelopathic effects and, thus, bio-herbicide potential of naturalised Desmodium uncinatum leaf (DuL) crude extract in various concentrations to control P. hysterophorus. Our results revealed that DuL crude extract can suppress P. hysterophorus, particularly at higher concentrations. The 75% and 100% DuL crude extract concentrations reduced the total leaf chlorophyll content by 26% and 22% in pots and plots, respectively. Further, these higher concentrations inhibited P. hysterophorus seed germination by 73% in petri dishes, 60% in pots, and 57% in plots, and negatively interfered with seedling growth vigour. Seedling stem heights under 75% and 100% DuL concentrations in pot and plot experiments was about 30% and 36% shorter than those sprayed with lower concentrations (< 70%) and the control, respectively. We show that naturalised plants with allelochemicals can be used as a management tool for controlling P. hysterophorus infestations in sub-Saharan Africa, particularly in Tanzania, and this method should become part of an integrated control toolkit being deployed in a community-based approach

Nanostructured Cu2_2O Synthesized via Bipolar Electrochemistry

Cuprous oxide (Cu$_2$O) was synthesized for the first time via an open bipolar electrochemistry (BPE) approach and characterized in parallel with the commercially available material. As compared to the reference, Cu$_2$O formed through a BPE reaction demonstrated a decrease in particle size; an increase in photocurrent; more efficient light scavenging; and structure-correlated changes in the flat band potential and charge carrier concentration. More importantly, as-synthesized oxides were all phase-pure, defect-free, and had an average crystallite size of 20 nm. Ultimately, this study demonstrates the impact of reaction conditions (e.g., applied potential, reaction time) on structure, morphology, surface chemistry, and photo-electrochemical activity of semiconducting oxides, and at the same time, the ability to maintain a green synthetic protocol and potentially create a scalable product. In the proposed BPE synthesis, we introduced a common food supplement (potassium gluconate) as a reducing and complexing agent, and as an electrolyte, allowing us to replace the more harmful reactants that are conventionally used in Cu$_2$O production. In addition, in the BPE process very corrosive reactants, such as hydroxides and metal precursors (required for synthesis of oxides), are generated in situ in stoichiometric quantity, providing an alternative methodology to generate various nanostructured materials in high yields under mild conditions

Quasiparticle Description of the QCD Plasma, Comparison with Lattice Results at Finite T and Mu

We compare our 2+1 flavor, staggered QCD lattice results with a quasiparticle picture. We determine the pressure, the energy density, the baryon density, the speed of sound and the thermal masses as a function of T and $\mu_B$. For the available thermodynamic quantities the difference is a few percent between the results of the two approaches. We also give the phase diagram on the $\mu_B$--T plane and estimate the critical chemical potential at vanishing temperature.Comment: 13 pages, 10 figure

Comprehensive Solid-State Characterization of Rare Earth Flouride Nanoparticles

The combination of multinuclear solid-state NMR spectroscopy and powder X-ray diffraction has been applied to characterize the octahedron-shaped crystalline nanoparticle products resulting from an inverse micelle synthesis. Rietveld refinements of the powder X-ray diffraction data from the nanoparticles revealed their general formula to be (H3O)Y3F10·xH2O. 1H magic-angle spinning (MAS) NMR experiments provided information on sample purity and served as an excellent probe of the zeolithic incorporation of atmospheric water. 19F MAS NMR experiments on a series of monodisperse nanoparticle samples of various sizes yielded spectra featuring three unique 19F resonances arising from three different fluorine sites within the (H3O)Y3F10·xH2O crystal structure. Partial removal of zeolithic water from the internal cavities and tunnels of the nanoparticles led to changes in the integrated peak intensities in the 19F MAS NMR spectra; the origin of this behavior is discussed in terms of 19F longitudinal relaxation. 19F–89Y variable-amplitude cross-polarization (VACP) NMR experiments on both stationary samples and samples under MAS conditions indicated that two distinct yttrium environments are present, and on the basis of the relative peak intensities, the population of one of the two sites is closely linked to the nanoparticle size. Both 19F MAS and 19F–89Y VACP/MAS experiments indicated small amounts of an impurity present in certain nanoparticles; these are postulated to be spherical amorphous YF3 nanoparticles. We discuss the importance of probing molecular-level structure in addition to microscopic structure and how the combination of these characterization methods is crucial for understanding nanoparticle design, synthesis, and application

Impact of Polypharmacy on Health-Related Quality of Life in Dialysis Patients

INTRODUCTION: Dialysis patients are often prescribed a large number of medications to improve metabolic control and manage coexisting comorbidities. However, some studies suggest that a large number of medications could also detrimentally affect patients' health-related quality of life (HRQoL). Therefore, this study aims to provide insight in the association between the number of types of medications and HRQoL in dialysis patients. METHODS: A multicentre cohort study was conducted among dialysis patients from Dutch dialysis centres 3 months after initiation of dialysis as part of the ongoing prospective DOMESTICO study. The number of types of medications, defined as the number of concomitantly prescribed types of drugs, was obtained from electronic patient records. Primary outcome was HRQoL measured with the Physical Component Summary (PCS) score and Mental Component Summary (MCS) score (range 0–100) of the Short Form 12. Secondary outcomes were number of symptoms (range 0–30) measured with the Dialysis Symptoms Index and self-rated health (range 0–100) measured with the EuroQol-5D-5L. Data were analysed using linear regression and adjusted for possible confounders, including comorbidity. Analyses for MCS and number of symptoms were performed after categorizing patients in tertiles according to their number of medications because assumptions of linearity were violated for these outcomes. RESULTS: A total of 162 patients were included. Mean age of patients was 58 ± 17 years, 35% were female, and 80% underwent haemodialysis. The mean number of medications was 12.2 ± 4.5. Mean PCS and MCS were 36.6 ± 10.2 and 46.8 ± 10.0, respectively. The mean number of symptoms was 12.3 ± 6.9 and the mean self-rated health 60.1 ± 20.6. In adjusted analyses, PCS was 0.6 point lower for each additional medication (95% confidence interval [95% CI]: −0.9 to −0.2; p = 0.002). MCS was 4.9 point lower (95% CI: −8.8 to −1.0; p = 0.01) and 1.0 point lower (95% CI: −5.1–3.1; p = 0.63) for the highest and middle tertiles of medications, respectively, than for the lowest tertile. Patients in the highest tertile of medications reported 4.1 more symptoms than in the lowest tertile (95% CI: 1.5–6.6; p = 0.002), but no significant difference in the number of symptoms was observed between the middle and lowest tertiles. Self-rated health was 1.5 point lower for each medication (95% CI: −2.2 to −0.7; p < 0.001). DISCUSSION/CONCLUSION: After adjustment for comorbidity and other confounders, a higher number of medications were associated with a lower PCS, MCS, and self-rated health in dialysis patients and with more symptoms

'Magic coins' and 'magic squares': the discovery of astrological sigils in the Oldenburg Letters

Enclosed in a 1673 letter to Henry Oldenburg were two drawings of a series of astrological sigils, coins and amulets from the collection of Strasbourg mathematician Julius Reichelt (1637–1719). As portrayals of particular medieval and early modern sigils are relatively rare, this paper will analyse the role of these medals in medieval and early modern medicine, the logic behind their perceived efficacy, and their significance in early modern astrological and cabalistic practice. I shall also demonstrate their change in status in the late seventeenth century from potent magical healing amulets tied to the mysteries of the heavens to objects kept in a cabinet for curiosos. The evolving perception of the purpose of sigils mirrored changing early modern beliefs in the occult influences of the heavens upon the body and the natural world, as well as the growing interests among virtuosi in collecting, numismatics and antiquities

Joint resummation in electroweak boson production

We present a phenomenological application of the joint resummation formalism to electroweak annihilation processes at measured boson momentum Q_T. This formalism simultaneously resums at next-to-leading logarithmic accuracy large threshold and recoil corrections to partonic scattering. We invert the impact parameter transform using a previously described analytic continuation procedure. This leads to a well-defined, resummed perturbative cross section for all nonzero Q_T, which can be compared to resummation carried out directly in Q_T space. From the structure of the resummed expressions, we also determine the form of nonperturbative corrections to the cross section and implement these into our analysis. We obtain a good description of the transverse momentum distribution of Z bosons produced at the Tevatron collider.Comment: 27 pages, LaTeX, 8 figures as eps files. Some additions to earlier version, this version as published in Phys. Rev. D66 (2002) 01401

Factorial validation of the Attitudes toward Women Scale for Adolescents (AWSA) in assessing sexual behaviour patterns in Bolivian and Ecuadorian adolescents

Background: Adolescents' health is greatly influenced by social determinants, including gender norms. Although research has shown that there is an association between gender attitudes and adolescents' sexual behaviour, few studies have assessed this relationship carefully. The Attitudes toward Women Scale for Adolescents (AWSA) is widely used to assess gender attitudes among adolescents; however, to our knowledge it has not been applied in Latin America. Objective: To apply AWSA in Latin America for the first time, to perform a factorial validation of this scale and to assess the relationship of gender attitudes and sexual behaviour in Bolivian and Ecuadorian adolescents. Design: This cross-sectional study was carried out in 2011 among 14-18 year olds in 20 high schools in Cochabamba (Bolivia) and six in Cuenca (Ecuador) as a part of a larger project. Schools were purposively selected. A Spanish version of the 12-item AWSA was employed for this study. The assessed aspects of adolescent sexual behaviour were: reported sexual intercourse, reported positive experience during last sexual intercourse and reported current use of contraception. The psychometric properties of AWSA were investigated, and both explanatory and confirmatory factorial analyses were performed. Results: The number of questionnaires included in the analysis was 3,518 in Bolivia and 2,401 in Ecuador. A factorial analysis of AWSA resulted in three factors: power dimension (PD), equality dimension (ED) and behavioural dimension (BD). ED showed the highest correlates with adolescent sexual behaviour. Higher scores of this dimension were associated with a more positive experience of sexual relationships, a higher current use of modern contraception and greater sexual activity among girls. Conclusions: This study revealed a three-factorial structure of AWSA and demonstrated that by employing factors, the sensitivity of AWSA increases as compared to using the scale as a whole to assess sexual behaviour. This could have important implications for future research on gender and the sexual experiences of adolescents