Potential impacts of petroleum exploration and exploitation on biodiversity in a Patagonian Nature Reserve, Argentina

Petroleum exploration and extraction are common on the Patagonian steppe, but their impacts on the native biodiversity have not been properly evaluated. We describe both activities in a Patagonian nature reserve and consider their potential impacts on biodiversity. More than 2025 km of seismic lines inside the reserve resulted in 87.21 m²/ha (0.9%) of directly affected land, and 793 fragments of native habitats were defined with a mean area of 1.26 ± 0.74 km². Vegetation recovery on seismic lines is extremely poor. We discuss the role of seismic lines as barriers to native species, and their significance in encouraging poaching and the expansion of exotic invasive plants. There is a high degree of overlap between current petroleum activities and areas of special conservation concern (high erosion risk, vegetation diversity, abundance of endemic plant species, and habitat quality for native vertebrates). All these have a significant impact on the efficiency of the conservation area and highlight the urgent need to implement appropriate mitigating actions.     

A New Functional Equation Analogous to CAUCHT-PEXIDER Functional Equation and its Application

The CAUCHY-PEXIDER functional equation H (x±y)=F(x) G(y) is generalized to the form H ((x^c±y^c)^1/c) = F(x) G(y), c≠0, assuming the function H(x) possesses a measurable majorant on a set of positive measure. The result is used to obtain a characterization of WEIBULL distribution. This functional equation is generalized to functions of vector variables.     

Strong and weak coupling in mixed-valence complexes bridged by 4,4′-azo-di(phenylcyanamido)

The complexes [{Ru(tpy^∗)(bpy)}₂(μ-adpc)][PF₆]₂ where tpy^∗ is 4,4′,4″-tri-(tert-butyl)-2,2′:6′,2″-terpyridine, bpy is 2,2′-bipyridine, and adpc²⁻ is 4,4′-azo-diphenylcyanamide dianion and trans,trans-[{Ru(tpy^∗)(pc)}₂(μ-adpc)] where pc⁻ is 2-pyrazine-carboxylato were prepared and characterized by cyclic voltammetry and spectroelectrochemical methods. Intervalence band properties and IR spectroelectrochemistry of the mixed-valence complexes [{Ru(tpy^∗)(bpy)}₂(μ-adpc)]³⁺ and trans,trans-[{Ru(tpy^∗)(pc)}₂(μ-adpc)]⁺ are consistent with delocalized and valence-trapped mixed-valence properties respectively. The reduction in mixed-valence coupling upon substituting a bipyridine ligand with 2-pyrazine carboxylato strongly suggests that hole-transfer superexchange is the dominant mechanism for metal-metal coupling in these complexes.     

Synthesis, X-ray crystal structure, DFT- and TDDFT-based spectroscopic property investigations on a mixed-ligand chromium(III) complex, bis[2-(2-hydroxyphenyl)benzimidazolato]-(1,10-phenanthroline)chromium(III) isophthalate

A mixed-ligand Cr(III) complex with 2-(2-hydroxyphenyl)benzimidazole, 1,10-phenanthroline and isophthalic acid, [Cr(pbm)₂(phen)]X_0.5 (1X_0.5) (Hpbm = 2-(2-hydroxyphenyl)benzimidazole; phen = 1,10-phenanthroline; H₂X = isophthalic acid) has been prepared by heating in aqueous solution and characterized, and the geometric structure and spectroscopic properties, investigated experimentally and theoretically by using the density functional theory level (DFT) and the time-dependent density functional theory level (TDDFT). The theoretical-experimental agreement is satisfactory. Further theoretical analyses of electronic structure and molecular orbitals have demonstrated that the low-lying absorption bands in UV-Vis spectrum are mainly π → π∗ ligand-to-ligand charge transfer transition (LLCT) and or π → (d_z²-d_x²-y²-d_yz) ligand-to-metal charge transfer transition (LMCT) in nature.     

Data-based optimization of protein production processes

While data-based modeling is possible in various ways, data-based optimization has not been previously described. Here we present such an optimization technique. It is based on dynamic programming principles and uses data directly from exploratory experiments where the influence of the adjustable variables u were tested at various values. Instead of formulating the performance index J as a function of time t within a cultivation process it is formulated as a function of the biomass x. The advantage of this representation is that in most biochemical production processes J(x) only depends of the vector u of the adjustable variables. This given, mathematical programming techniques allow determining the desired optimal paths u _opt (x) from the x-derivatives of J(x). The resulting u _opt (x) can easily be transformed back to the u(t) profiles that can then be used in an improved fermentation run. The optimization technique can easily be explained graphically. With numerical experiments the feasibility of the method is demonstrated. Then, two optimization runs for recombinant protein formations in E. coli are discussed and experimental validation results are presented.     

Rhodopsin-transducin heteropentamer: three-dimensional structure and biochemical characterization

The process of vision is initiated when the G protein-coupled receptor, rhodopsin (Rho), absorbs a photon and transitions to its activated Rho^∗ form. Rho^∗ binds the heterotrimeric G protein, transducin (G_t) inducing GDP to GTP exchange and G_t dissociation. Using nucleotide depletion and affinity chromatography, we trapped and purified the resulting nucleotide-free Rho^∗·G_t complex. Quantitative SDS–PAGE suggested a 2:1 molar ratio of Rho^∗ to G_t in the complex and its mass determined by scanning transmission electron microscopy was 221 ± 12 kDa. A 21.6 Å structure was calculated from projections of negatively stained Rho^∗·G_t complexes. The molecular envelope thus determined accommodated two Rho molecules together with one G_t heterotrimer, corroborating the heteropentameric structure of the Rho^∗·G_t complex.     

Halide abstraction reactions of Sb(V) chloride: Synthesis and characterisation of hexachloroantimonate salts of M(II) M = Zn,Mg; M(III) M = Cr; and M(IV) M = Ti,Sn and related Cp2M(IV) M = Ti,Zr and Hf

Reactions of SbCl₅ with various covalent metal halides in MeCN have been studied as a convenient and direct route to metal hexachloroantimonate salts via Sb(V) halide abstraction. The isolation and characterization (Ir, Vis-UV, ¹H NMR spectroscopic and microanalytical) of the complexes [Zn(MeCN)₆][SbCl₆]₂, [CrCl₂(MeCN)₄][SbCl₆], [SnCl₃(MeCN)₃][SbCl₆], [TiCl₂(MeCN)₄][SbCl₆]₂, [Cp₂M(Cl)(MeCN)_x][SbCl₆] M = ti, x = 1; M = Zr, Hf, x = 2, and [Cp₂M(MeCN)_y][SbCl₆]₂ M = Ti, y = 2; M = Zr, Hf, y = 3, is described. The reaction of MgCl₂ with SbCl₅ was carried out in EtOAC as solvent and gave [Mg(EtOAc)₆][SbCl₆]₂. ¹²¹Sb NMR, IR and UV spectroscopic measurements provide positive identification of the SbCl_6⁻ anion.     

Insights into the nature of Mo(V) species in solution: Modeling catalytic cycles for molybdenum enzymes

The tris(pyrazolyl)borate and related tripodal N-donor ligands originally developed by Trofimenko stabilize mononuclear compounds containing Mo^VIO₂, Mo^VIO, Mo^VO, and Mo^IVO units and effectively inhibit their polynucleation in organic solvents. Dioxo-Mo(VI) complexes of the type LMoO₂(SPh), where L = hydrotris(3,5-dimethylpyrazol-1-yl)borate (Tp^∗), hydrotris(3-isopropylpyrazol-1-yl)borate (Tp^iPr), and hydrotris(3,5-dimethyl-1,2,4-triazol-1-yl)borate (Tz) and related derivatives are the only model systems that mimic the complete reaction sequence of sulfite oxidase, in which oxygen from water is ultimately incorporated into product. The quasi-reversible, one-electron reduction of Tp^∗MoO₂(SPh) in acetonitrile exhibits a positive potential shift upon addition of a hydroxylic proton donor, and the magnitude of the shift correlates with the acidity of the proton donor. These reductions produce two Mo(V) species, [Tp^∗Mo^VO₂(SPh)]⁻ and Tp^∗Mo^VO(OH)(SPh), that are related by protonation. Measurement of the relative amounts of these two Mo(V) species by EPR spectroscopy enabled the pK_a of the Mo^V(OH) unit in acetonitrile to be determined and showed it to be several pK_a units smaller than that for water in acetonitrile. Similar electrochemical-EPR experiments for Tp^iPrMoO₂(SPh) indicated that the pK_a for its Mo^V(OH) unit was ∼1.7 units smaller than that for Tp^∗Mo^VO(OH)(SPh). Density functional theory calculations also predict a smaller pK_a for Tp^iPrMo^VO(OH)(SPh) compared to Tp^∗Mo^VO(OH)(SPh). Analysis of these results indicates that coupled electron-proton transfer (CEPT) is thermodynamically favored over the indirect process of metal reduction followed by protonation. The crystal structure of Tp^iPrMoO₂(SPh) is also presented.     

Ordering Dynamics in Neuron Activity Pattern Model: An Insight to Brain Functionality

We study the domain ordering kinetics in d = 2 ferromagnets which corresponds to populated neuron activities with both long-ranged interactions, V(r) ∼ r ⁻ⁿ and short-ranged interactions. We present the results from comprehensive Monte Carlo (MC) simulations for the nonconserved Ising model with n ≥ 2, interaction range considering near and far neighbors. Our model results could represent the long-ranged neuron kinetics (n ≤ 4) in consistent with the same dynamical behaviour of short-ranged case (n ≥ 4) at far below and near criticality. We found that emergence of fast and slow kinetics of long and short ranged case could imitate the formation of connections among near and distant neurons. The calculated characteristic length scale in long-ranged interaction is found to be n independent (L(t) ∼ t ^1/(n−2)), whereas short-ranged interaction follows L(t) ∼ t ^1/2 law and approximately preserve universality in domain kinetics. Further, we did the comparative study of phase ordering near the critical temperature which follows different behaviours of domain ordering near and far critical temperature but follows universal scaling law.     

Differences in the rate of redistribution of receptors for concanavalin A in vivo and in vitro on spermatozoa from normal mice and from sterile mice carrying different T/t locus haplotypes

The redistribution of receptors for fluorescein isothiocyanate-conjugated concanavalin A (FITC-con A) on mouse spermatozoa during maturation has been studied in vivo and in vitro using normal mice and sterile mice carrying two different lethal T-locus haplotypes (t^x/t^y). Receptors for FITC-con A, uniformly distributed on the head of functionally immature sperm within the proximal epididymis, become localized as the cells acquire functional maturity within the distal portion of the epididymis. Examining samples of epididymal sperm incubated for short periods of time in vitro, a similar increase in the proportion of discretely labeled cells is observed with time. Sperm from sterile t^x/t^y males also show redistribution of receptors for FITC-con A in vivo and in vitro; however, a significantly smaller proportion of cells of the population achieve a discrete distribution of receptors comparable to that displayed on sperm from fertile mice. It is concluded that mouse sperm undergo redistribution of receptors for con A normally in acquiring functional maturity within the epididymis and upon liberation from the male urogenital tract; the sterility of t^x/t^y mice may be due to a genetically based impairment of plasma membrane reorganization reflected in sluggish redistribution of receptors for con A shown by these cells in vivo and in vitro.     

Bis(phosphine)-Pd(II) and -Pt(II) complexes containing chiral tetrazole-thiolato rings: Synthesis, structures, and reactivity toward some electrophiles

Bis(azido)bis(phosphine)-Pd(II) and -Pt(II) complexes, [M(N₃)₂L₂] {L = PMe₃, PEt₃, PMe₂Ph, dppe = 1,2-bis(diphenylphosphino)ethane}, underwent 1,3-dipolar cycloaddition with organic chiral isothiocyanates (R^∗-NCS: R^∗ = (S)-(+)-1-phenylethyl, (R)-(−)-1-phenylethyl, (±)-1-phenylethyl, (S)-(+)-1-indanyl) to give the corresponding tetrazole-thiolato Pd(II) and Pt(II) complexes, trans-[M{S[CN₄(R^∗)]}₂L₂] or [M{S[CN₄(R^∗)]}₂(dppe)]. Spectroscopic (IR and NMR) and X-ray structural analyses of the products showed that the absolute configuration of the starting organic isothiocyanates is retained throughout the reaction. Further treatments of the isolated tetrazole-thiolato complexes with electrophiles such as HCl or benzoyl chloride produced heterocyclic compounds containing a tetrazole thione or a tetrazolyl sulfide group. In addition, organic tetrazole thiones, [S = {CN₄H(R^∗)}] containing a chiral moiety, were prepared from NaN₃ and R^∗-NCS in the presence of water.     

Rate Constants and the Variation of Random Concentration Curves in a 2-Compartment System

In biology and medicine many substances and drugs enter the system not at regular time intervals but rather according to a random process. In the present article a situation is investigated where input enters a 2-compartment system according to a Poisson process. The arising two random concentration curves y(t), one for the central and one for the peripheral compartment are discussed (shot noise). The equations for E[y(t)] and Var [y(t)] are derived. The dependence of E[y(t)] and Var [y(t)] and of the index of dispersion ID[y(t)] on the rate parameters is analysed and discussed in both compartments. The arising calculations were considerably simplified by means of “Mathematica”, a computer program which allows to perform symbolic calculations.     

Ultrafast excited-state dynamics of photoisomerizing complexes fac-[Re(Cl)(CO)3(papy)2] and fac-[Re(papy)(CO)3(bpy)] (papy = trans-4-phenylazopyridine)

The character and dynamics of low-lying electronic excited states of the complexes fac-[Re(Cl)(CO)₃(papy)₂] and fac-[Re(papy)(CO)₃(bpy)]⁺ (papy = trans-4-phenylazopyridine) were investigated using stationary (UV-Vis absorption, resonance Raman) and ultrafast time-resolved (visible, IR absorption) spectroscopic methods. Excitation of [Re(Cl)(CO)₃(papy)₂] at 400 nm is directed to ¹ππ^∗(papy) and Re → papy ¹MLCT excited states. Ultrafast (?1.4 ps) intersystem crossing (ISC) to ³nπ^∗(papy) follows. Excitation of [Re(papy)(CO)₃(bpy)]⁺ is directed to ¹ππ^∗(papy), ¹MLCT(papy) and ¹MLCT(bpy). The states ³nπ^∗(papy) and ³MLCT(bpy) are then populated simultaneously in less then 0.8 ps. The ³MLCT(bpy) state decays to ³nπ^∗(papy) with a 3 ps time constant. ³nπ^∗(papy) is the lowest excited state for both complexes. It undergoes vibrational cooling and partial rotation around the -NN- bond, to form an intermediate with a nonplanar papy ligand in less than 40 ps. This species then undergoes ISC to the ground state potential energy surface, on which the trans and cis isomers are formed by reverse and forward intraligand papy rotation, respectively. This process occurs with a time constant of 120 and 100 ps for [Re(Cl)(CO)₃(papy)₂] and [Re(papy)(CO)₃(bpy)]⁺, respectively. It is concluded that coordination of papy to the Re center accelerates the ISC, switching the photochemistry from singlet to triplet excited states. Comparison with analogous 4-styrylpyridine complexes (M. Busby, P. Matousek, M. Towrie, A. Vl?ek Jr., J. Phys. Chem. A 109 (2005) 3000) reveals similarities of the decay mechanism of excited states of Re complexes with ligands containing -NN- and -CC- bonds. Both involve sub-picosecond ISC to triplets, partial rotation around the double bond and slower ISC to the trans or cis ground state. This process is about 200 times faster for the -NN- bonded papy ligand. The intramolecular energy transfer from the ³MLCT-excited ^∗Re(CO)₃(bpy) chromophore to the intraligand state of the axial ligand occurs for both L = stpy and papy with a comparable rate of a few ps.     

Reaction of iron and ruthenium halogenide complexes with GaCp and AlCp: Insertion, Cp transfer reactions and orthometallation

The reactions of the Fe(II) and Ru(II) halogenide complexes [Fe(PPh₃)₂Br₂], [Fe(NCCH₃)₂Br₂], [Ru(PPh₃)₃Cl₂], and [Ru(dmso)₄Cl₂] with GaCp^∗ and AlCp^∗, respectively, are investigated. The reactions of [FeBr₂L₂] with ECp^∗ exclusively proceed via Cp^∗ transfer, leading to [FeCp^∗(GaCp^∗)(GaBr₂)(PPh₃)] (1) (L = PPh₃, E = Ga), [FeCp^∗(GaCp^∗)₂ (GaBr₂)] (2) (L = NCCH₃, E = Ga) and [FeCp^∗(μ³-H)(κ²-(C₆H₄)PPh₂)(AlCp^∗)(AlBr₂)] (3) (L = PPh₃, E = Al), the latter of which is formed via orthometallation of one PPh₃ ligand. The reaction of [Ru(dmso)₄Cl₂] leads to the homoleptic complex [Ru(GaCp^∗)₆Cl₂] (4) in high yields, while [Ru(PPh₃)₃Cl₂] gives 4 in rather low yields. The reason for this difference in reactivity is investigated and it is shown that Cp^∗ transfer and orthometallation are the limiting side reactions of the reaction of [Ru(PPh₃)₃Cl₂] with GaCp^∗. All compounds were characterized by NMR spectroscopy, and single crystal X-ray diffraction studies were performed for 1, 3, and 4.     

Saving species in a snap: On the feasibility and efficacy of augmented reality-based wildlife interactions for conservation

Interactions with wildlife can contribute to biodiversity conservation outcomes, though safety and accessibility considerations limit animal encounters from being a viable strategy. This investigation explores the feasibility of mobile augmented reality to facilitate interactions with wildlife and encourage biodversity conservation. A mobile augmented reality experience (Snapchat lens), titled “Penguin Rescue!”, was created to allow users to rehabilitate an oil-slicked virtual penguin. Study 1 distributed the lens globally to Snapchat users (N = 63,605) who spent an average of 47 s rehabilitating the penguin; psychographic data showed pro-environmental interests were not associated with the lens’ use. Study 2 employed a within-subjects experimental design (N = 80) to examine the effects of Penguin Rescue! on conservation outcomes. Results showed that the interaction increased connectedness with the species. Moreover, social presence and plausibility served as key mechanisms contributing to environmental concern and behavioral intentions. Overall, results clarify how biophilic interactions via augmented reality can benefit biodiversity conservation.     

Long-term socio-ecological research (LTSER) for biodiversity protection – A complex systems approach for the study of dynamic human–nature interactions

Recently, the long-term ecological research (LTER) program in the US was evaluated. In its 20-year review report, the National Science Foundation recognizes the achievements of the past and specifies guidance for future development. Among other aspects, research activities of the next decade should concentrate on a new core area: biological diversity, and, to inform environmental policy on the interrelationships and reciprocal impacts of ecological and human systems, LTER is requested “to partner with social scientists” at all existing or newly selected research sites (http://www.nsf.gov/od/lpa/news/02/pr0265.htm). In Europe, LTER activities head in the same direction. To create durable integration of European biodiversity research capacity and to address biodiversity policy needs, long-term socio-ecological research (LTSER) sites should serve as real-world laboratories for interdisciplinary and policy relevant research (http://www.lter-europe.ceh.ac.uk and www.alter-net.info). In this paper, we explore how LTER could meet the challenges of the future: the increase of knowledge on issues of biological diversity and of partnership approaches among the natural and social sciences in common research facilities – the LTSER sites.Regarding biological diversity we explore, in particular, the advantages for improving: (1) ecological-economic modelling, a powerful technique for analysing complex human–nature interaction, (2) the design of choice experiments, a rather new evaluation method for assessing the benefits of conservation and (3) the understanding of biodiversity as complex social dilemma. Regarding the issue of research collaboration, we focus on the geographical scale of LTSER sites and, on a more general level, on the demands of research management in terms of project design, common knowledge and organisation of research teams.     

Photophysical properties, X-ray structures, electrochemistry, and DFT computational chemistry of osmium complexes

We report the synthesis of phosphorescent divalent osmium complexes of the form [Os(N-N)₂(L-L) or Os(L-L)₂(N-N)]²⁺ (PF₆)₂ where N-N is a derivative of 1,10-phenanthroline, and L-L is a diarsine or diphosphine ligand: 1,2-bis(dimethylphosphino)ethane, 1,2-bis(dicyclohexylphosphino)ethane, or 1,2-bis(dimethylarseno)benzene. X-ray structures have been determined, luminescent and electrochemical properties have been measured and DFT calculations have been performed on the complexes. The emission lifetime of complexes of structure Os(II)(L-L)₂(N-N) are longer than the those of Os(II)(N-N)₂(L-L). The DFT calculations show that there is significant mixing of the π−π^∗ into the dπ−π^∗ charge-transfer state for the complexes of the form Os(II)(L-L)₂(N-N) resulting in a longer lived excited state. Through DFT calculations we were able to conclude that the HOMO of the complexes is a d orbital on the osmium while the LUMO is the b₁(ψ) π^∗ system of the phenanthroline. However, we found that the HOMO did not have the correct symmetry to enable strong charge transfer to the phenanthroline to be observed, and the strong MLCT transition observed in the spectra is the metal d HOMO(−1) to the b1 π^∗ LUMO of the phenanthroline.     

Cis and Trans isomers of 4-hydroxy-8-sphingenine in plant cerebrosides

Pure cerebroside was isolated from hay and concentrate (extracted oilseed used for cattle feed), and the composition of the long-chain bases determined. The principal base was the cis isomer of 4-hydroxy-8-sphingenine (t18: 1 ^8c) which has not been reported before. The other trihydroxy bases were t18: 1^8t and t18: 0.Allylic and non-allylic dihydroxy bases were found in concentrate cerebroside and identified as d18: 1⁴, d18: 2^{4, x}, d18: 0 and d18: 1^x (x = 8?). Cis and trans isomers of mid-chain double bonds (position x) were tentatively identified, and the dihydroxy bases are probably identical to those recently found in wheat flour cerebroside [2].     

Structural comparison of (pentamethylcyclopentadienyl)iridium(III) azido complexes containing potentially N,S-bidentate N-heterocyclic thiolates: 2- or 8-quinolinethiolate and benzimidazole-2-thiolate

The crystal structures of mononuclear (azido)(pentamethylcyclopentadienyl)iridium(III) complexes bearing 2- or 8-quinolinethiolate (n-Sqn⁻), [Cp^∗Ir(N₃)(n-Sqn)] {n = 2 (1) or 8 (2); Cp^∗ = η⁵-C₅Me₅} have been determined by X-ray analysis. The 2-Sqn complex, 1, acquires severe steric strains in the four-membered κ²N,S chelate ring, while the 8-Sqn isomer, 2, forms a strain-free five-membered planar κ²N,S chelate ring. It has also been revealed that the corresponding benzimidazole-2-thiolate (Hbimt⁻) complex, which was obtained similarly to the above n-Sqn complexes from [Cp^∗Ir(N₃)₂]₂ and Na(Hbimt), takes an unsymmetrical dinuclear structure bridged by two Hbimt⁻ ligands with different bonding modes, [Cp^∗Ir(N₃){μ(S:N¹)-Hbimt}{μ(S:S)-Hbimt}Ir(N₃)Cp^∗] · MeOH (3).