Examining the Tradeoffs of Green Infrastructure for Stormwater Management: Ecosystem Services vs. Environmental and Human Health Impacts

As green stormwater infrastructure (GI) practices become more widely implemented, it is important to develop a full understanding of both the positive and negative ways that GI practices may influence environmental and human health. Additionally, as climate change leads to shifts in precipitation patterns, it is necessary to understand how the resulting changes in stormwater runoff volume, soil moisture, and vegetation species composition will impact both biogeochemical cycling and the production of ecosystem services and disservices. The overall objective of this study was to compare green stormwater infrastructure practices by weighing the tradeoffs that exist between negative impacts such as greenhouse gas production and the positive impacts provided by ecosystem services including recreational and educational infrastructure and opportunities, carbon sequestration and other regulating ecosystem services, and habitat provisioning for biodiversity support. In this study, six types of GI practices were examined: green roofs (n = 3), wet ponds (n = 2), dry ponds (n = 4), bioretention basins (n = 3), rain gardens (n = 3), and vegetated swales (n = 3). Rates of potential production of methane (CH4) and carbon dioxide (CO2) greenhouse gases were measured using anaerobic soil incubations. Soil samples were also analyzed for organic matter, moisture, and C and N content. Vegetation surveys were used to determine percent cover and Shannon diversity (H) of all plant species and percent cover of native, non-native, and invasive plant species. A rubric was used to assess availability of two categories of cultural ecosystem services: recreational and educational opportunities at each site. A comparative cradle-to-grave life cycle assessment (LCA) was conducted for evaluation of the environmental and human health impacts associated with the materials, construction, maintenance, operation, and end-of-life decommissioning of a selection of the GI sites included in this study. A hypothetical situation involving one example of conventional stormwater management infrastructure, an underground pre-cast concrete detention basin, was included in the LCA for comparison to GI practices. All measurements were highly variable between study sites, even between sites of the same GI type. Two sites, a green roof and a vegetated swale, exhibited significantly higher production rates for CH4 and CO2 and contained significantly higher organic matter and C and N content than all other sites. Linear regression results suggest that higher rates of potential production of CH4 and CO2 are driven by increased soil organic matter, and to a lesser extent, by increased soil moisture. Average soil C and N were lowest for the wet pond and bioretention basin GI categories and highest in the green roofs, and soil C and N were both correlated with production rates of CH4 and CO2 gases. LCA results indicate that for most sites, the majority of total life cycle negative environmental impacts were caused during the construction and decommissioning phases. One green roof had much higher impacts compared to the other sites and the highest global warming impacts. When compared to all GI types included in this study, vegetated swales had the highest vegetation species diversity, the highest potential for providing cultural ecosystem services, the highest % carbon content, only moderate potential production rates of CH4 and CO2, and low total lifecycle impacts as measured by the LCA. Although there were tradeoffs for all GI types and despite variations between individual sites; when considering all factors, vegetated swales were the GI type which provided the highest ratio of benefits to negative impacts

Collider Signature of T-quarks

Little Higgs models with T Parity contain new vector-like fermions, the T-odd quarks or "T-quarks", which can be produced at hadron colliders with a QCD-strength cross section. Events with two acoplanar jets and large missing transverse energy provide a simple signature of T-quark production. We show that searches for this signature with the Tevatron Run II data can probe a significant part of the Little Higgs model parameter space not accessible to previous experiments, exploring T-quark masses up to about 400 GeV. This reach covers parts of the parameter space where the lightest T-odd particle can account for the observed dark matter relic abundance. We also comment on the prospects for this search at the Large Hadron Collider (LHC).Comment: 5 pages, 3 figure

Constraining Light Colored Particles with Event Shapes

Using recently developed techniques for computing event shapes with Soft-Collinear Effective Theory, LEP event shape data is used to derive strong model-independent bounds on new colored particles. In the effective field theory computation, colored particles contribute in loops not only to the running of alpha_s but also to the running of hard, jet and soft functions. Moreover, the differential distribution in the effective theory explicitly probes many energy scales, so event shapes have strong sensitivity to new particle thresholds. Using thrust data from ALEPH and OPAL, colored adjoint fermions (such as a gluino) below 51.0 GeV are ruled out to 95% confidence level. This is nearly an order-of-magnitude improvement over the previous model-independent bound of 6.3 GeV.Comment: 4 pages, 2 figure

High-resolution spectroscopy of triplet states of Rb2 by femtosecond pump-probe photoionization of doped helium nanodroplets

The dynamics of vibrational wave packets in triplet states of rubidium dimers (Rb2) formed on helium nanodroplets are studied using femtosecond pump-probe photoionization spectroscopy. Due to fast desorption of the excited Rb2 molecules off the droplets and due to their low internal temperature, wave packet oscillations can be followed up to very long pump-probe delay times >1.5ns. In the first excited triplet state (1)^3\Sigma_g^+, full and fractional revivals are observed with high contrast. Fourier analysis provides high-resolution vibrational spectra which are in excellent agreement with ab initio calculations

Probing Trilinear Gauge Boson Interactions via Single Electroweak Gauge Boson Production at the LHC

We analyze the potential of the CERN Large Hadron Collider (LHC) to study anomalous trilinear vector-boson interactions W^+ W^- \gamma and W^+ W^- Z through the single production of electroweak gauge bosons via the weak boson fusion processes q q -> q q W (-> \ell^\pm \nu) and q q -> q q Z(-> \ell^+ \ell^-) with \ell = e or \mu. After a careful study of the standard model backgrounds, we show that the single production of electroweak bosons at the LHC can provide stringent tests on deviations of these vertices from the standard model prediction. In particular, we show that single gauge boson production exhibits a sensitivity to the couplings \Delta \kappa_{Z,\gamma} similar to that attainable from the analysis of electroweak boson pair production.Comment: 20 pages, 6 figure

Limits on the Electromagnetic and Weak Dipole Moments of the Tau-Lepton in E_6 Superstring Models

We obtain limits on the electromagnetic and weak dipole moments of the tau-lepton in the framework of a Left-Right symmetric model (LRSM) and a class of $E_6$ inspired models with an additional neutral vector boson $Z_\theta$. Using as an input the data obtained by the L3 and OPAL Collaborations for the reaction $e^+e^-\to \tau^+\tau^-\gamma$, we get a stringent limit on the LRSM mixing angle $\phi$, $-1.66\times 10^{-3}< \phi<1.22\times 10^{-3}$, which in turn induces bounds on the tau weak dipole moments which are consistent with the bounds obtained recently by the DELPHI and ALEPH Collaborations from the reaction $e^+e^-\to \tau^+\tau^-$. We also get similar bounds for the weak dipole moments of the tau lepton in the framework of $E_6$ superstring models.Comment: 18 pages, 5 figure

Design of double-walled carbon nanotubes for biomedical applications

Double-walled carbon nanotubes (DWNTs) prepared by catalytic chemical vapour deposition were functionalized in such a way that they were optimally designed as a nano-vector for the delivery of small interfering RNA (siRNA), which is of great interest for biomedical research and drug development. DWNTs were initially oxidized and coated with a polypeptide (Poly(Lys:Phe)), which was then conjugated to thiol-modified siRNA using a heterobifunctional cross-linker. The obtained oxDWNT–siRNA was characterized by Raman spectroscopy inside and outside a biological environment (mammalian cells). Uptake of the custom designed nanotubes was not associated with detectable biochemical perturbations in cultured cells, but transfection of cells with DWNTs loaded with siRNA targeting the green fluorescent protein (GFP) gene, serving as a model system, as well as with therapeutic siRNA targeting the survivin gene, led to a significant gene silencing effect, and in the latter case a resulting apoptotic effect in cancer cells

Cellular localization, accumulation and trafficking of double-walled carbon nanotubes in human prostate cancer cells

Carbon nanotubes (CNTs) are at present being considered as potential nanovectors with the ability to deliver therapeutic cargoes into living cells. Previous studies established the ability of CNTs to enter cells and their therapeutic utility, but an appreciation of global intracellular trafficking associated with their cellular distribution has yet to be described. Despite the many aspects of the uptake mechanism of CNTs being studied, only a few studies have investigated internalization and fate of CNTs inside cells in detail. In the present study, intracellular localization and trafficking of RNA-wrapped, oxidized double-walled CNTs (oxDWNT–RNA) is presented. Fixed cells, previously exposed to oxDWNT–RNA, were subjected to immunocytochemical analysis using antibodies specific to proteins implicated in endocytosis; moreover cell compartment markers and pharmacological inhibitory conditions were also employed in this study. Our results revealed that an endocytic pathway is involved in the internalization of oxDWNT–RNA. The nanotubes were found in clathrin-coated vesicles, after which they appear to be sorted in early endosomes, followed by vesicular maturation, become located in lysosomes. Furthermore, we observed co-localization of oxDWNT–RNA with the small GTP-binding protein (Rab 11), involved in their recycling back to the plasma membrane via endosomes from the trans-golgi network