Continuous-variable protocol for oblivious transfer in the noisy-storage model.

Cryptographic protocols are the backbone of our information society. This includes two-party protocols which offer protection against distrustful players. Such protocols can be built from a basic primitive called oblivious transfer. We present and experimentally demonstrate here a quantum protocol for oblivious transfer for optical continuous-variable systems, and prove its security in the noisy-storage model. This model allows us to establish security by sending more quantum signals than an attacker can reliably store during the protocol. The security proof is based on uncertainty relations which we derive for continuous-variable systems, that differ from the ones used in quantum key distribution. We experimentally demonstrate in a proof-of-principle experiment the proposed oblivious transfer protocol for various channel losses by using entangled two-mode squeezed states measured with balanced homodyne detection. Our work enables the implementation of arbitrary two-party quantum cryptographic protocols with continuous-variable communication systems.

Quantum cryptography beyond quantum key distribution.

Quantum cryptography is the art and science of exploiting quantum mechanical effects in order to perform cryptographic tasks. While the most well-known example of this discipline is quantum key distribution (QKD), there exist many other applications such as quantum money, randomness generation, secure two- and multi-party computation and delegated quantum computation. Quantum cryptography also studies the limitations and challenges resulting from quantum adversaries-including the impossibility of quantum bit commitment, the difficulty of quantum rewinding and the definition of quantum security models for classical primitives. In this review article, aimed primarily at cryptographers unfamiliar with the quantum world, we survey the area of theoretical quantum cryptography, with an emphasis on the constructions and limitations beyond the realm of QKD.

A realistic model under which the genetic code is optimal.

The genetic code has a high level of error robustness. Using values of hydrophobicity scales as a proxy for amino acid character, and the mean square measure as a function quantifying error robustness, a value can be obtained for a genetic code which reflects the error robustness of that code. By comparing this value with a distribution of values belonging to codes generated by random permutations of amino acid assignments, the level of error robustness of a genetic code can be quantified. We present a calculation in which the standard genetic code is shown to be optimal. We obtain this result by (1) using recently updated values of polar requirement as input; (2) fixing seven assignments (Ile, Trp, His, Phe, Tyr, Arg, and Leu) based on aptamer considerations; and (3) using known biosynthetic relations of the 20 amino acids. This last point is reflected in an approach of subdivision (restricting the random reallocation of assignments to amino acid subgroups, the set of 20 being divided in four such subgroups). The three approaches to explain robustness of the code (specific selection for robustness, amino acid-RNA interactions leading to assignments, or a slow growth process of assignment patterns) are reexamined in light of our findings. We offer a comprehensive hypothesis, stressing the importance of biosynthetic relations, with the code evolving from an early stage with just glycine and alanine, via intermediate stages, towards 64 codons carrying todays meaning.

Complete insecurity of quantum protocols for classical two-party computation.

A fundamental task in modern cryptography is the joint computation of a function which has two inputs, one from Alice and one from Bob, such that neither of the two can learn more about the other's input than what is implied by the value of the function. In this Letter, we show that any quantum protocol for the computation of a classical deterministic function that outputs the result to both parties (two-sided computation) and that is secure against a cheating Bob can be completely broken by a cheating Alice. Whereas it is known that quantum protocols for this task cannot be completely secure, our result implies that security for one party implies complete insecurity for the other. Our findings stand in stark contrast to recent protocols for weak coin tossing and highlight the limits of cryptography within quantum mechanics. We remark that our conclusions remain valid, even if security is only required to be approximate and if the function that is computed for Bob is different from that of Alice.

Fate of beta-blocker human pharmaceuticals in surface water: comparison of measured and simulated concentrations in the Glatt Valley Watershed, Switzerland.

This study focused on the occurrence and fate of four beta-blockers (atenolol, sotalol, metoprolol, propranolol) in wastewater and surface water. Measured concentrations were compared with predicted concentrations using an implementation of the geo-referenced model GREAT-ER for the Glatt Valley Watershed (Switzerland). Particularly, the question was addressed how measured and simulated data could complement each other for the exposure assessment of human pharmaceuticals and other micropollutants entering surface water through wastewater treatment plants (WWTP). Concentrations in the Glatt River ranged from

Cryptography from noisy storage.

We show how to implement cryptographic primitives based on the realistic assumption that quantum storage of qubits is noisy. We thereby consider individual-storage attacks; i.e., the dishonest party attempts to store each incoming qubit separately. Our model is similar to the model of bounded-quantum storage; however, we consider an explicit noise model inspired by present-day technology. To illustrate the power of this new model, we show that a protocol for oblivious transfer is secure for any amount of quantum-storage noise, as long as honest players can perform perfect quantum operations. Our model also allows us to show the security of protocols that cope with noise in the operations of the honest players and achieve more advanced tasks such as secure identification.

Defining the chronic impacts of atenolol on embryo-larval development and reproduction in the fathead minnow (Pimephales promelas).

Atenolol is a beta-adrenergic receptor antagonist ('beta-blocker') widely used for the treatment of angina, glaucoma, high blood pressure and other related conditions. Since atenolol is not appreciably metabolized in humans, the parent compound is the predominant excretory product, and has been detected in sewage effluent discharges and surface waters. Consequently, atenolol has been chosen as a reference pharmaceutical for a European Union-funded research consortium, known as ERAPharm (http://www.erapharm.org), which focused on the fate and effects of pharmaceuticals in the environment. Here, we present data generated within this project from studies assessing population-relevant effects in a freshwater fish species. Using fathead minnows (Pimephales promelas) as a standard OECD test species, embryo-larval development (early life stage or ELS) and short-term (21 d) adult reproduction studies were undertaken. In the ELS study, the 4d embryo NOEC(hatching) and LOEC(hatching) values were 10 and >10mg/L, respectively, and after 28 d, NOEC(growth) and LOEC(growth) values were 3.2 and 10mg/L, respectively (arithmetic mean measured atenolol concentrations were >90% of these nominal values). In the short-term reproduction study, NOEC(reproduction) and LOEC(reproduction) values were 10 and >10mg/L, respectively (mean measured concentrations were 77-96% of nominal values), while the most sensitive endpoint was an increase in male fish condition index, giving NOEC(condition index) and LOEC(condition index) values of 1.0 and 3.2mg/L, respectively. The corresponding measured plasma concentration of atenolol in these fish was 0.0518 mg/L. These data collectively suggest that atenolol has low chronic toxicity to fish under the conditions described, particularly considering the low environmental concentrations reported. These data also allowed the assessment of two theoretical approaches proposed as predictors of the environmental impact of human pharmaceuticals: the Huggett 'mammalian-fish leverage model'; and the acute:chronic ratio (ACR). The Huggett model gave a measured human: fish effect ratio (ER) of 19.3 for atenolol, which compared well with the predicted ER of 40.98. Moreover, for an ER of 19.3, the model suggests that chronic testing may be warranted, and from our resultant effects data, atenolol does not cause significant chronic effects in fathead minnow at environmentally realistic concentrations. The calculated ACR for atenolol is >31.25, which is far lower than that of 17 alpha-ethinylestradiol and other potent steroidal oestrogens, thus further supporting the observed low toxicity. The data produced for atenolol here fit well with both approaches, but also highlight the importance of generating 'real' experimental data with which to calibrate and validate such models.

Benzotriazole is antiestrogenic in vitro but not in vivo.

Benzotriazole (BT) is an anticorrosive agent well known for its use in aircraft deicing and antifreeze fluids but also used in dishwasher detergents. It is highly persistent in the environment; therefore, BT is frequently found in runoff emanating from large airports as well as in the surrounding groundwater. In addition, BT has recently been found to be ubiquitous in Swiss wastewater treatment plant effluents and their receiving waters; however, very little chronic toxicity data is available on which to base a sound ecological risk assessment of this chemical. In vitro assays conducted using a recombinant yeast (anti-) estrogen assay indicated that BT possessed clear antiestrogenic properties. This chemical was approximately 100-fold less potent than Tamoxifen, which was used as a positive control. A subsequent in vivo study, however, involving analysis of vitellogenin induction and somatic indices in adult fathead minnows (Pimephales promelas) exposed to BT at concentrations of 10, 100, and 1,000 mug/L for two weeks showed no evidence of antiestrogenic activity by this compound. The possibility exists that higher concentrations of BT may yet induce the type of activity observed in vitro, although the concentrations used here already far exceed those reported in surface-water samples. Furthermore, adverse effects may be observed in fish or other organisms exposed to BT for a longer period than employed here, although such studies are costly and unlikely to be included in standard risk assessment procedures. A rigorous investigation of the chronic toxicity of BT is imperative.

Organic pollutants in compost and digestate. Part 2. Polychlorinated dibenzo-p-dioxins, and -furans, dioxin-like polychlorinated biphenyls, brominated flame retardants, perfluorinated alkyl substances, pesticides, and other compounds.

Compost and digestate are important recycling fertilizers and have beneficial effects on soil parameters. However, they can contain significant amounts of organic pollutants. Here, the first comprehensive data set on dibenzo-p-dioxins and -furans (PCDD/F), dioxin-like polychlorinated biphenyls (DL-PCB), brominated flame retardants, perfluorinated alkyl substances (PFAS), pesticides, phthalates, nonylphenol and chlorinated paraffins (CP) in source-separated compost and digestate from Switzerland is presented (n = 3-18). The median summation 17PCDD/F and summation 12DL-PCB concentrations were at 3.2 ng I-TEQ kg(-1)dry weight (dw) and 3.0 ng WHO-TEQ kg(-1)dw, respectively. Brominated diphenyl ether 209 (BDE 209) accounted for 72% of the total polyBDE content (10 microg kg(-1)dw). Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) levels were at 100 and 0.51 microg kg(-1)dw, respectively. PFAS were identified for the first time in compost and digestate (median concentration 6.3 microg kg(-1)dw, summation 21compounds). Out of 269 pesticides analysed, 30 fungicides, 14 herbicides, eight insecticides and one acaricide were detected. Di-(2-ethylhexyl)phthalate (DEHP) median concentration accounted for 280 microg kg(-1)dw and nonylphenol was below the detection limit of 1 mg kg(-1)dw. The sum of short and medium chain CP was between 90 and 390 microg kg(-1)dw. The concentrations observed were at or above the levels found in background soils, which are the main recipient of compost and digestate. Where actually applied, compost can contribute considerably to the total input of organic pollutants to the soil. However, on a total Swiss agricultural area base, inputs seem to be limited.

Benzotriazole and tolyltriazole as aquatic contaminants. 1. Input and occurrence in rivers and lakes.

The complexing agents benzotriazole (BT) and tolyltriazole (TT) are not only widely applied as anticorrosives, e.g., in aircraft deicer and anti-icer fluid (ADAF), but they are also used for so-called silver protection in dishwasher detergents. Due to their low biodegradability and limited sorption tendency, BT and TT are only partly removed in wastewater treatment. Residual concentrations of BT and TT were determined in ambient surface waters in Switzerland including 7 rivers which have distinct water flows and receive treated wastewater effluents at various dilution ratios. A maximum BT concentration of 6.3 microg/L was found in the Glatt River, and a maximum mass flow of 277 kg BT per week was observed in the Rhine River. In most cases, TT was about a factor 5-10 less abundant. During winter 2003/4, BT mass flows at 2 locations in the lower stretch of the Glatt River clearly indicated the input from nearby Zurich airport, where BT was applied as an anticorrosive ADAF component. BT concentrations measured in the three lakes Greifensee, Lake Zurich, and Lake Geneva were approximately 1.2, 0.1-0.4, and 0.2 microg/L, respectively. The observed environmental occurrences indicate that BT and TT are ubiquitous contaminants in the aquatic environment and that they belong to the most abundant individual water pollutants.

Benzotriazoles, alkylphenols and bisphenol A in municipal wastewaters and in the Glatt River, Switzerland.

BACKGROUND: Many organic micropollutants occur at trace concentrations in municipal wastewater effluents and in the aquatic environment. Some of these xenobiotic chemicals can be considered as 'emerging' contaminants and some are suspect to have endocrine disrupting effects. Among the latter are nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA), which deserve special attention due to their ubiquitous occurrence in the aquatic environment. The complexing agents benzotriazole (BT) and tolyltriazole (TT) are applied as anticorrosive agents (e.g. in cooling and hydraulic fluids, in antifreezing fluids, in aircraft deicing fluids, in dish washing liquids for silver protection), as antifogging agents and as intermediates for the synthesis of various chemicals. The environmental occurrence of NP and OP is caused by the fact that they are intermediate products (metabolites) in the biodegradation of alkylphenol polyethoxylate surfactants. BPA is globally used for the production of polycarbonate and epoxy resins. METHODS: BT, TT, NP, OP and BPA were quantitatively determined in municipal wastewater effluents in Switzerland and in the Glatt River. The analytes were enriched by solid-phase enrichment. BT and TT were determined underivatized by electrospray LC/tandem MS. Reversed-phase LC was performed on octylsilica columns with isocratic water/methanol elution. Multiple reaction monitoring of the positive ions provided selective and sensitive detection for reliable quantifications. NP, OP and BPA were determined by GC/MS after derivatization with N-methyl-N-(trimethylsilyl)-trifluoroacetamide. RESULTS AND DISCUSSION: BT and TT concentrations in primary and secondary effluents of municipal wastewater treatment plants varied from below 10 to 100 microg/L. The ranges of the concentrations in the Glatt River in ng/L were 636-3,690 for BT, 122-628 for TT, 68-326 for NP, 6-22 for OP and 9-76 for BPA. The corresponding mass flows in g/d were 93-1,870 for BT, 18-360 for TT, 24-183 for NP, 1-16 for OP and 2-72 for BPA. The concentrations and mass flows of NP in the River Glatt were drastically lower than the analogous values found 15 years ago. Thus, a substantially decreased environmental exposure can be observed due to the reduction of the use of alkyphenol polyethoxylate surfactants in Switzerland. The current concentrations of NP, OP and BPA are within the ranges reported for weakly impacted surface waters. CONCLUSION: The investigated contaminants occur at quantitatively measurable but varying concentrations in municipal wastewaters and in the Glatt River reflecting their ubiquitous input into wastewaters and their different behaviour during biological wastewater treatment.

Influences of sedimentary organic matter quality on the bioaccumulation of 4-nonylphenol by estuarine amphipods.

Nonylphenol (NP) is a moderately persistent, hydrophobic chemical with endocrine-disrupting and acute narcotic effects in aquatic biota. Concern exists about the ultimate fate of NP in aquatic ecosystems and the potential for bioaccumulation by benthic biota from the sediment with the potential for further transfer to higher trophic levels. Our goals were to determine if benthic amphipods bioaccumulate significant amounts of NP from sediment and to determine how additions of organic matter influence NP bioaccumulation by amphipods. Estuarine sediment was spiked with 14C-NP and enriched with two types of organic carbon (OC) sources of different nutritional qualities. Macrophytic algae (Ulva species) were used as a labile and nutritious OC source. Wood lignins were used as a refractory and low-nutrition OC source. Nonylphenol bioaccumulation was measured in Eohaustorius estuarius, Grandidierella japonica, and Corophium salmonis after 16 d of exposure. Nonylphenol accumulation was inversely proportional to OC quantity, but was unaffected by OC nutritional quality. Significant differences were found in the accumulation patterns between the three amphipod species. Mean biota-sediment accumulation factors ranged from 8.1 to 33.9 in E. estuarius, from 4.6 to 17.2 in G. japonica, and averaged 7.1 in male C. salmonis and 16.0 in female C. salmonis. These accumulation factors indicate that estuarine amphipods could constitute an important source of NP to higher trophic levels, such as juvenile fish.