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POLARBEAR-2b (PB-2b) is the second of three cryogenic receivers of the Simons Array cosmic microwave background polarization experiment. PB-2b contains over 7500 transition-edge sensor (TES) bolometers cooled to 250 mK and read out using digital frequency-division multiplexing (DfMux). Stray impedance in the DfMux circuit obscures TES characterization and affects TES dynamic behavior. In order to accurately characterize TESs, it is necessary to account for stray impedance in the bias circuit. We define a stray impedance model, and we describe the technique used to measure model parameters in situ and to remove their effects on TES characterization. We use the same model to predict TES dynamic behavior and show good agreement between data and the model.

Atomic-level qubits in silicon are attractive candidates for large-scale quantum computing; however, their quantum properties and controllability are sensitive to details such as the number of donor atoms comprising a qubit and their precise location. This work combines machine learning techniques with million-atom simulations of scanning tunnelling microscopic (STM) images of dopants to formulate a theoretical framework capable of determining the number of dopants at a particular qubit location and their positions with exact lattice site precision. A convolutional neural network (CNN) was trained on 100,000 simulated STM images, acquiring a characterisation fidelity (number and absolute donor positions) of >98% over a set of 17,600 test images including planar and blurring noise commensurate with experimental measurements. The formalism is based on a systematic symmetry analysis and feature-detection processing of the STM images to optimise the computational efficiency. The technique is demonstrated for qubits formed by single and pairs of closely spaced donor atoms, with the potential to generalise it for larger donor clusters. The method established here will enable a high-precision post-fabrication characterisation of dopant qubits in silicon, with high-throughput potentially alleviating the requirements on the level of resources required for quantum-based characterisation, which will otherwise be a challenge in the context of large qubit arrays for universal quantum computing.

Substitutional donor atoms in silicon are promising qubits for quantum computation with extremely long relaxation and dephasing times demonstrated. One of the critical challenges of scaling these systems is determining inter-donor distances to achieve controllable wavefunction overlap while at the same time performing high fidelity spin readout on each qubit. Here we achieve such a device by means of scanning tunnelling microscopy lithography. We measure anti-correlated spin states between two donor-based spin qubits in silicon separated by 16${\pm}1$ nm. By utilizing an asymmetric system with two phosphorus donors at one qubit site and one on the other (2P-1P), we demonstrate that the exchange interaction can be turned on and off via electrical control of two in-plane phosphorus doped detuning gates. We determine the tunnel coupling between the 2P-1P system to be 200 MHz and provide a roadmap for the observation of two-electron coherent exchange oscillations., 19 pages, 10 figures - DEV053 - Team Viper

Solid-state spin-based qubits offer good prospects for scaling based on their long coherence times and nexus to large-scale electronic scale-up technologies. However, high-threshold quantum error correction requires a two-dimensional qubit array operating in parallel, posing significant challenges in fabrication and control. While architectures incorporating distributed quantum control meet this challenge head-on, most designs rely on individual control and readout of all qubits with high gate densities. We analysed the fan-out routing overhead of a dedicated control line architecture, basing the analysis on a generalised solid-state spin qubit platform parameterised to encompass Coulomb confined (e.g. donor based spin qubits) or electrostatically confined (e.g. quantum dot based spin qubits) implementations. The spatial scalability under this model is estimated using standard electronic routing methods and present-day fabrication constraints. Based on reasonable assumptions for qubit control and readout we estimate 102–105 physical qubits, depending on the quantum interconnect implementation, can be integrated and fanned-out independently. Assuming relatively long control-free interconnects the scalability can be extended. Ultimately, the universal quantum computation may necessitate a much higher number of integrated qubits, indicating that higher dimensional electronics fabrication and/or multiplexed distributed control and readout schemes may be the preferredstrategy for large-scale implementation.

We show that under the matrix product state formalism the states produced in Shor's algorithm can be represented using $$O(\max (4lr^2, 2^{2l}))$$O(max(4lr2,22l)) space, where l is the number of bits in the number to factorise and r is the order and the solution to the related order-finding problem. The reduction in space compared to an amplitude formalism approach is significant, allowing simulations as large as 42 qubits to be run on a single processor with 32 GB RAM. This approach is readily adapted to a distributed memory environment, and we have simulated a 45-qubit case using 8 cores with 16 GB RAM in approximately 1 h.

The rates (k) of hydroxymethylation of phenol, resorcinol, phloroglucinol, and several methylphenols in diluted 10% dimethylformamide aqueous alkaline solution were calculated based on the consumption of phenols and formaldehyde. Thek values of phloroglucinol and resorcinol relative to that of phenol were about 62000 and 1200 times, respectively. The phenols that have methyl or hydroxyl groups at the C-3 or C-5 position (or both) have larger rate constants than phenols with substituents at other positions. Several kinds of atomic charge of the carbons on the aromatic ring of phenols were calculated using the semiempirical orab initio method. The correlations between the averagek (Ave.k) and average electrostatic charges (Ave.q) at the carbons were fairly good. Highest occupied molecular orbitals (HOMO) were observed. The best correlation between Ave.k and Ave.q was obtained when diphenols and triphenols were assumed to exist in solution as their respective di-anion.

A commercial enzyme preparation with β-galactosidase and cellulase activities catalyzed the synthesis of 6′-galactosyl lactose (18% yield) from lactose with a better selectivity (62%) for production of the product than thermostable enzymes and most mesophilic enzymes (32–43%).

Modified milkfats were produced via interesterification (acidolysis) reactions of butteroil and conjugated linoleic acid (CLA) in a packed bed reactor containing an immobilized lipase preparation from Candida antarctica. The rate expression for the interesterification reaction is of the generalized Michaelis–Menten form. Significant enrichment of butteroil in CLA residues was accomplished at reactor space times (fluid residence times) of 2–4 h at 40–60 °C, but the optimum operating temperature was ca. 50 °C. Approximately 80–90% of the free CLA fed to the reactor can be converted to its esterified form.

Rates and product distributions have been determined for the consecutive esterification reactions of conjugated linoleic acid (CLA) with glycerol in the presence of an immobilized Candida antarctica lipase from Novo Nordisk (Lipozyme IM). In a solvent-free environment, both rates and product distributions are affected by the ratio of reactants, temperature, and hydration level. For mole ratios of CLA to glycerol ranging from 1/1 to 3/1, incorporation of at least 95% of the original CLA into the product acylglycerols was achieved in less than 7 h of reaction at 50°C. © Rapid Science Ltd. 1998

Kid goat pre-gastric esterase immobilized in a hollow fiber reactor was used to hydrolyse butteroil at buffer pH values of 5.0, 6.0 and 7.0. Overall hydrolysis proceeded fastest at pH 6.0, but changes in volatile fatty acid ratios with pH suggest that the same enzyme:substrate system can produce different flavor profiles, e. g., at pH 6.0 the relative rate of production of undesirable soaplike flavors is minimized.

Kid and calf pregastric esterases were semi-purified by micro- and ultrafiltration of a crude tissue preparation. When the resulting solutions were utilized to immobilize these enzymes in a polypropylene hollow fiber reactor, the activities obtained when both techniques were employed were greater than those observed when only microfiltration was performed.

A novel chemical reactor, consisting of β-galactosidase fromAspergillus oryzae immobilized on a ribbed membrane made from polyvinyl-chloride and silica, was used to hydrolyze the lactose constituent of skim milk. Multiresponse nonlinear regression methods were employed to determine the kinetic parameters of rate expressions based on a proposed enzymatic mechanism that includes the formation of oligosaccharides. HPLC methods were employed to monitor the concentrations of all species present in the effluent stream. For the experimental conditions used in this research, a rate expression that includes the inhibition effect of α-galactose is sufficient to model the reaction network.

Microbial lipases from Candida cylindracea, Pseudomonas sp., Mucor miehei and Candida antarctica were screened for their ability to incorporate conjugated linoleic acid into butteroil triacylglycerides. The lipase from Candida antarctica was employed in a substrates-only medium to increase the conjugated linoleic acid content of the acylglycerides from 0.6 to 15 g/100 g fat.

Thirty infants were diagnosed with extrahepatic biliary atresia (EBA) from July 1978 to July 1989; 28 have undergone a Kasai or Lilly-Altman modification of the Kasai portoenterostomy; 2 were excluded from surgery because they presented after 3 months of age and had advanced biliary cirrhosis. Immediate postoperative drainage (>30 ml/day was achieved in 24 patients (86%), with 14 (50%) surviving free of jaundice. The average follow-up was 2.25 years (range 3 months to 10 years); the longest survivor is 10.3 years old. The overall survival was 64%, and 5-year survival 50%. Of 24 infants operated on at

A system based on missense suppressor mutations affecting an Escherichia coli glycine tRNA was used for measuring the relative frequencies of a single base substitution, a tandem double base substitution and a non-tandem double base substitution all occurring in the same triplet and in the same mutagenic treatment. RNA sequencing studies reported here have shown that the glyUsuGAA mutation results from a CCC→TTC tandem double substitution in the anticodon region of the gene coding for tRNA GGG Gly . Thus the suGAA allele, like the previously characterized suGAG and suAGA alleles of glyU, affects the tRNA anticodon in the manner anticipated from the coding specificity. The system for measuring relative frequencies of the three suppressor mutations entails the mutagenic treatment of a culture lysogenic for a λ transducing phage carrying glyU+, the wild type tRNA gene. Following mutagenesis the culture is induced for phage production and the resulting lysate assayed for phage carrying any one of the three suppressor alleles. An important feature of the system is that it circumvents the problem of distinguishing the rare double mutations from the more abundant background. We have found that with doses of ultraviolet irradiation sufficient to reduce the viable cell count 98–99%, the tandem double base substitution (suGAA) occurs 0.01 as frequently as the single (suGAG). The tandem double substitution occurs about 4 times more frequently than the nontandem double substitution (suAGA).

Operating costs for the production of Baker’s yeast from hydrolyzed permeate from the ultrafiltration of cottage cheese whey were calculated as a function of the level of lactose conversion in the immobilized lactase reactor. These costs were calculated for the case of 90% conversion of lactose in the reactor and compared to those that result when running the reactor at lower conversions with recycle of unreacted lactose. Total operating costs were estimated by combining individual operating costs for the immobilized enzyme reactor, costs associated with processing a lactose recycle stream, and energy costs associated with cooling the reactor feed stream and sterilizing the hydrolysate stream. It was determined that operating costs are minimized at about 9.9 ¢/lb. of lactose when the reactor is run at approx. 72% conversion. This represents a savings of 2.4 ¢/lb. of lactose over the case of a once-through 90% conversion of lactose in the reactor.

Most research on contraceptive behavior has focused on individual women rather than on couples. A study of 101 college dating couples examined three issues that have been largely ignored in previous research: the applicability of Lindemann's (1974) stage model of contraceptive use to couples, agreement between partners in reports of contraceptive methods used, and boyfriend's characteristics as correlates of contraceptive use. Stages of contraceptive use were increasingly related to the women's prior sexual experience, and decreasingly related to the man's. Agreement on birth control methods was very high for reports of prescription methods at most recent intercourse, but low for reports of no birth control at first intercourse. Use of prescription methods at most recent intercourse was more strongly related to the women's social characteristics (father's education, religious background) than to the man's. Results suggest that focusing on women as individuals is a useful strategy for research on contraceptive use, at least for unmarried women.

We propose a two-part generalization about sex differences in entering into and giving up romantic attachments: (1) Men tend to fall in love more readily than women; (2) women tend to fall out of love more readily than men. Evidence in support of these generalizations is derived from a longitudinal study of 231 college student dating couples. The data suggest that women are more cautious than men about entering into romantic relationships, more likely to compare these relationships to alternatives, more likely to end a relationship that seems ill fated, and better able to cope with rejection. We consider several possible explanations of these sex differences from the standpoints of psychoanalytic theory, the social and economic context of mate selection, and the socialization of men and women in the management of their own emotions. To evaluate these (and any other) explanations, further research might profitably investigate whether and to what degree these sex differences are found in other segments of the population.

We have found that mild ultraviolet irradiation of Escherichia coli leads to a duplication of the glyT purD region of the chromosome to the extent that 3–5% of all surviving chromosomes carry a genetic duplication of this material. The duplications vary in size from less than one to more than five minutes of the chromosome. While the endpoints of the duplications vary, seven of ten characterized have one end between the purD and metA loci, and five of these seven have the other endpoint near the argH locus. Consequently, the region between purD and metA (only 0.1 minutes) seems to be particularly prone to participating in abnormal recombinational events. The UV-induced damage leading to the genetic duplications is subject to dark repair, suggesting the involvment of pyrimidine dimers. Other mutagens such as nitrous acid, ethyl methanesulfonate and nitrosoguanidine are also effective in generating these duplications at high frequency. Evidence is discussed which indicates that some and probably most of the duplications are tandem duplications. However, at least one example was found that is more readily explained by a translocation.

The relative preferences of four rhesus monkeys for reward probability versus reward amount when they were maintained on a low-protein (3.35%) diet were compared with those demonstrated when they were fed an adequate (13.4%) protein diet. Four stimulus objects, each signifying a different combination of reward frequency and amount (100%-one piece, 50%-2 pieces, 33%-three pieces, or 25%-four pieces), were presented in pairs, one pair per daily session, with trial schedules providing the same amount of reward within each set of 12 trials. Selections of the more frequently rewarded objects, but with lesser amounts per trial, were significantly higher during the low-protein phase than during either the preceding or the following normal-diet phases. Protein deprivation produces a changed motivational state making these animals less tolerant of infrequent or postponed reinforcement.

Aggressive responses were tabulated for albino rats under conditions of shock stimulation only, food deprivation only, and shock plus food deprivation. Results indicated that while deprivation alone did not result in aggression as defined in the experiment, deprivation plus shock elicited more aggression than shock alone. Further, the number of aggressive responses was found to vary positively with amount of deprivation.