Physiological Stress Responses,Fecal Marking Behavior,and Reproduction in Wild European Pine Martens (<Emphasis Type="Italic">Martes martes</Emphasis>)

The relationship among physiological stress responses, fecal marking behavior, and reproduction in male and female European pine martens was investigated. Between July 2004 and June 2007, 145 fresh fecal samples were collected in a protected area of northwest Spain. Fecal DNA was used for specific identification by using the polymerase chain reaction-restriction fragment length polymorphism technique. Glucocorticoids (cortisol) and sex steroid hormones (P, progesterone; E, estradiol; T, testosterone) were quantified by enzyme immunoassays. Sex was assigned according to concentrations of T+P+E and the T/P ratio. Fecal cortisol concentrations were higher in males than in females. Feces with a presumptive marking function (on conspicuous substrates, above ground level, and/or in latrines) had higher mean levels of cortisol than those that were on inconspicuous substrates and/or at ground level, for both males and females. Fecal mark density was highest in spring, when mean levels of fecal cortisol were more elevated. Therefore, the higher physiological stress levels in females could be due to female physiological state (late-term pregnancy and lactation), competition for resources connected to birth, or food resources for offspring rearing. In males, the increase could be due to higher male competition for access to females during pro-estrus and estrus. Our results suggest that scent marking in European pine martens is related to reproduction and is involved in intersexual and intrasexual communication.     

Healable,Stable and Stiff Hydrogels: Combining Conflicting Properties Using Dynamic and Selective Three‐Component Recognition with Reinforcing Cellulose Nanorods

Nanocomposite hydrogels are prepared combining polymer brush‐modified ‘hard’ cellulose nanocrystals (CNC) and ‘soft’ polymeric domains, and bound together by cucurbit[8]uril (CB[8]) supramolecular crosslinks, which allow dynamic host–guest interactions as well as selective and simultaneous binding of two guests, i.e., methyl viologen (the first guest) and naphthyl units (the second guest). CNCs are mechanically strong colloidal rods with nanometer‐scale lateral dimensions, which are functionalized by surface‐initiated atom transfer radical polymerization to yield a dense set of methacrylate polymer brushes bearing naphthyl units. They can then be non‐covalently cross‐linked through simple addition of poly(vinyl alcohol) polymers containing pendant viologen units as well as CB[8]s in aqueous media. The resulting supramolecular nanocomposite hydrogels combine three important criteria: high storage modulus (G′ > 10 kPa), rapid sol–gel transition (<6 s), and rapid self‐healing even upon aging for several months, as driven by balanced colloidal reinforcement as well as the selectivity and dynamics of the CB[8] three‐component supramolecular interactions. Such a new combination of properties for stiff and self‐healing hydrogel materials suggests new approaches for advanced dynamic materials from renewable sources.     

Droplet and Fluid Gating by Biomimetic Janus Membranes

The ability to gate (i.e., allow or block) droplet and fluid transport in a directional manner represents an important form of liquid manipulation and has tremendous application potential in fields involving intelligent liquid management. Inspired by passive transport across cell membranes which regulate permeability by transmembrane hydrophilic/hydrophobic interactions, macroscopic hydrophilic/hydrophobic Janus‐type membranes are prepared by facile vapor diffusion or plasma treatments for liquid gating. The resultant Janus membrane shows directional water droplet gating behavior in air‐water systems. Furthermore, membrane‐based directional gating of continuous water flow is demonstrated for the first time, enabling Janus membranes to act as facile fluid diodes for one‐way flow regulation. Additionally, in oil‐water systems, the Janus membranes show directional gating of droplets with integrated selectivity for either oil or water. The above remarkable gating properties of the Janus membranes could bring about novel applications in fluid rectifying, microchemical reaction manipulation, advanced separation, biomedical materials and smart textiles.     

Water Resources Development in the Lower Senegal River Basin: Conflicting Interests,Environmental Concerns and Policy Options

The Senegal River is the lifeline of the westernmost part of the Sahelian zone in Africa. This zone has extreme problems with high population growth, rapid and uncontrolled urbanization, climate changes, widespread poverty, growing inequity, ethnic confrontations and stagnant economic development. This paper analyses the management system of Lac de Guiers--one of the largest lakes in West Africa--which is among the Senegal River's key management entities. A Bayesian network model is used to study the conflicting interests among the various stakeholders, the environmental and social concerns in the region and the viability of a series of policy options for water resources development.     

Microbiological treatment of fertilizer solid waste material containing phenoxyalkanoic herbicides 2,4-D and MCPP

The purpose of the work was to evaluate the feasibility of a biological treatment process for herbicide-containing solid waste material from a fertilizer-manufacturing plant. The waste contained approximately 1·5% (w/w) 2,4-dichlorophenoxyacetate (2,4-D) and 1·4% (w/w) 2-(2-methyl-4-chlorophenoxy)propionate (MCPP, mecoprop). Both herbicides could be dissolved from the bulk matrix (vermiculite) within 3 days of chemical leaching in aqueous solution. Upon subsequent inoculation of herbicide-degrading bacterial consortia derived from soil samples adjacent to the plant, 2,4-D was completely degraded in the presence of up to 5% (w/v) pulp densities. The biodegradation of MCPP was concurrent but incomplete. The degradation process was acid-producing, and pH control enhanced the rates of herbicide degradation.     

Adsorption of cholate anions on layered double hydroxides: effects of temperature,ionic strength and pH

Layered Double Hydroxides are a class of materials that can be described as positively charged planar layers consisting of divalent and trivalent cations in the center of edge-sharing octahedra. The positive charge in the LDH layers must be compensated by anion intercalation. These materials have applications that include adsorption and/or sorption of anionic species. Cholic acid is one of the main acids produced by the liver. It promotes transport of lipids through aqueous systems. This work reports on the adsorption of Cholic acid anions in MgAl–CO₃–LDH taking ionic strength, pH, and temperature effects into account. The adsorbent was characterized by different techniques. Cholate anion adsorption was performed at two different temperatures (298 and 323 K), two different ionic strength conditions (0.0 and 0.1 M of NaCl), and two different pH values (7.0 and 10.0). The results show that the sorption of Cholate anions in calcined LDH can remove a considerable amount of these anions from the medium. Cholate anion adsorption in the LDH with no calcining also occurs, but at a lower amount.     

Selecting the nozzle assortment for a Gantry-type placement machine

Electronics manufacturing systems employ increasingly multi-head gantry machines, where several vacuum nozzles are used simultaneously in pick-and-place operations to insert components on bare PCBs. Their use includes several options that have an impact on the overall manufacturing speed of the machine. In the present paper we address the problem of selecting the nozzles for this kind of a gantry machine, which is an important subproblem of the larger scheduling problem of multi-head gantry machines. Nozzles come in different types, and different types of components may require different types of nozzles in their placing. We address first a case where a single PCB type is manufactured and the only limitation on the number of nozzles is given by the capacity of the placement head. Then we discuss the case where there is a budget limitation on the total cost of the nozzles we can buy. We show that both of these problems can be solved optimally by the means of efficient greedy algorithms. We also discuss the case of selecting nozzles when manufacturing multiple different PCB types.     

Organic memory using [6,6]-phenyl-C(61) butyric acid methyl ester: morphology, thickness and concentration dependence studies

We report a simple memory device in which the fullerene-derivative [6,6]-phenyl-C(61) butyric acid methyl ester (PCBM) mixed with inert polystyrene (PS) matrix is sandwiched between two aluminum (Al) electrodes. Transmission electron microscopy (TEM) images of PCBM:PS films showed well controlled morphology without forming any aggregates at low weight percentages (<10?wt%) of PCBM in PS. Energy dispersive x-ray spectroscopy (EDX) analysis of the device cross-sections indicated that the thermal evaporation of the Al electrodes did not lead to the inclusion of Al metal nanoparticles into the active PCBM:PS film. Above a threshold voltage of <3?V, independent of thickness, a consistent negative differential resistance (NDR) is observed in devices in the thickness range from 200 to 350?nm made from solutions with 4-10?wt% of PCBM in PS. We found that the threshold voltage (V(th)) for switching from the high-impedance state to the low-impedance state, the voltage at maximum current density (V(max)) and the voltage at minimum current density (V(min)) in the NDR regime are constant within this thickness range. The current density ratio at V(max) and V(min) is more than or equal to 10, increasing with thickness. Furthermore, the current density is exponentially dependent on the longest tunneling jump between two PCBM molecules, suggesting a tunneling mechanism between individual PCBM molecules. This is further supported with temperature independent NDR down to 240?K.     

Estimates of benthic fluxes of nutrients across the sediment-water interface (Guarapiranga reservoir, São Paulo, Brazil)

Concentration profiles of nutrients (dissolved organic carbon, nitrate, nitrite, ammonium and soluble reactive phosphorus) were determined in pore waters from sediment from the Guarapiranga reservoir (S?o Paulo, Brazil). Redox potential and acid volatile sulfide measurements on bulk sediment samples were determined in the field and laboratory, respectively. The sediment redox potential ranged from -170 to -220 mV at 0-1 cm and increased to somewhat higher values at 20 cm. The acid volatile sulfide (AVS) profile had a bimodal pattern with concentration peaks at 3 cm (27-55 mg kg(-1)) and 14 cm (70-110 mg kg(-1)). Dissolved organic carbon (DOC) concentrations increased from the surface (4.7-5.6 mg l(-1)) to 20 cm (values up to 12 mg l(-1)). The concentration of ammonium increased significantly with depth, with maximum concentrations occurring at 15 cm; nitrate-nitrite concentrations only increased appreciably at 10 cm. The SRP profiles increased in concentration from the surface to approximately 10-cm depth, with a maximum value of 1200 microg H2PO4- l(-1). Benthic fluxes from the sediment into the pore water ranged from 278 to 339 mg cm(-2) year(-1) for ammonium ions and from 8 to 18 mg cm(-2) year(-1) for SRP. These upward diffusive fluxes correspond to 47-70% and to 10-24% of the total deposition of N and P measured in the reservoir, respectively. The burial rates for N and P in these sediments are 30-54% and 76-89%, respectively.