Reconstruction of east–west deep water exchange in the low latitude Atlantic Ocean over the past 25,000 years

Radiogenic neodymium isotopes have been used as a water mass mixing proxy to investigate past changes in ocean circulation. Here we present a new depth transect of deglacial neodymium isotope records measured on uncleaned planktic foraminifera from five cores spanning from 3300 to 4900 m on the Mauritanian margin, in the tropical eastern Atlantic as well as an additional record from 4000 m on the Ceara Rise in the equatorial western Atlantic. Despite being located under the Saharan dust plume, the eastern Atlantic records differ from the composition of detrital inputs through time and exhibit similar values to the western Atlantic foraminiferal Nd across the deglaciation. Therefore we interpret the foraminiferal values as recording deep water Nd isotope changes. All six cores shift to less radiogenic values across the deglaciation, indicating that they were bathed by a lower proportion of North Atlantic Deep Water during the Last Glacial Maximum (LGM) relative to the Holocene. The eastern Atlantic records also show that a neodymium isotope gradient was present during the LGM and during the deglaciation, with more radiogenic values observed at the deepest sites. A homogeneous water mass observed below 3750 m in the deepest eastern Atlantic during the LGM is attributed to the mixing of deep water by rough topography as it passes from the western Atlantic through the fracture zones in the Mid-Atlantic Ridge. This implies that during the LGM the low latitude deep eastern Atlantic was ventilated from the western Atlantic via advection through fracture zones in the same manner as occurs in the modern ocean. Comparison with carbon isotopes indicates there was more respired carbon in the deep eastern than deep western Atlantic during the LGM, as is also seen in the modern Atlantic Ocean.Radiocarbon analyses were supported by NERC radiocarbon grant 1752.1013 and Nd isotope analyses by NERC grants NERC NE/K005235/1 and NERC NE/F006047/1 to AMP. JNWH was supported by a Rutherford Memorial Scholarship

Fracture of the penis: A report of two cases

We present two cases of fracture of the penis in two young men at the extremes of the social strata the first an unemployed tailor while the other a practicing engineer. The first one was a bachelor while the other wasmarried with children. In the first case, the fracture occurred during masturbation while in the second case it occurred during consensual intercoursewith hiswife on top. In the first case the fracture occurred at the base of the peniswith associated rupture of the deep dorsal veinwhile in the second case it affected themid-shaftwith urethral rupture and blood at the tip of the penis at presentation. Both of them presented within two hours of their injuries with deformed, swollen and tender penis. Laubscher's subcoronal sleeve operation with evacuation of clots and repair of the tear with absorbable sutures to ensure a leak-proof repair was promptly performedwith no complications.Both patients experienced spontaneous erectionwhilst in hospital evenwith indwelling catheter in place. The wife of the second case became pregnant six months after the repair. Counselingwas successfulwith the engineer butwas unsuccessfulwith the tailor-bachelorwho continuedwith masturbation despite professional help.Thoughwe published the first case of fracture of the penis in this centre almost a decade ago, we still found it necessary to report these newcasesmanaged after we created awareness of this uncommon condition in our environment in order to highlight the presentations and the factors that influenced outcome

Sustained high-level expression of human factor IX (hFIX) after liver-targeted delivery of recombinant adeno-associated virus encoding the hFIX gene in rhesus macaques

The feasibility, safety, and efficacy of liver-directed gene transfer was evaluated in 5 male macaques (aged 2.5 to 6.5 years) by using a recombinant adeno-associated viral (rAAV) vector (rAAV-2 CAGG-hFIX) that had previously mediated persistent therapeutic expression of human factor IX (hFIX; 6%-10% of physiologic levels) in murine models. A dose of 4 × 1012 vector genomes (vgs)/kg of body weight was administered through the hepatic artery or portal vein. Persistence of the rAAV vgs as circular monomers and dimers and high-molecular-weight concatamers was documented in liver tissue by Southern blot analysis for periods of up to 1 year. Vector particles were present in plasma, urine, or saliva for several days after infusion (as shown by polymerase chain reaction analysis), and the vgs were detected in spleen tissue at low copy numbers. An enzyme-linked immunosorption assay capable of detecting between 1% and 25% of normal levels of hFIX in rhesus plasma was developed by using hyperimmune serum from a rhesus monkey that had received an adenoviral vector encoding hFIX. Two macaques having 3 and 40 rAAV genome equivalents/cell, respectively, in liver tissue had 4% and 8% of normal physiologic plasma levels of hFIX, respectively. A level of hFIX that was 3% of normal levels was transiently detected in one other macaque, which had a genome copy number of 25 before abrogation by a neutralizing antibody (inhibitor) to hFIX. This nonhuman-primate model will be useful in further evaluation and development of rAAV vectors for gene therapy of hemophilia B. © 2002 by The American Society of Hematology

Fast image reconstruction for near-field terahertz imaging with multistatic non-uniform sparse arrays

Conference paper presented at Radar Sensor Technology XXVII, Orlando, FL, USA, 30 April - 5 May, 2023.In this paper, first, the structure of a linear sparse periodic array for two-dimensional scanning is described. Then, based on its characteristics, an algorithm is presented for fast image reconstruction of the scene in a near-field (NF) multistatic terahertz imaging scenario. Although the basis of this algorithm is developed in the Fourier domain, it is compatible with the non-uniform structure of the array and also takes into account the phase deviations caused by multistatic imaging in NF. The performance of the proposed approach is evaluated with numerical data obtained from electromagnetic simulations in FEKO as well as experimental data. The results are discussed in terms of computational time on the central processing unit and graphics processing unit as well as the quality of the reconstructed image.Leverhulme Trust under Research Leadership Award RL-2019-019. The work of Shaoqing Hu is funded by Brunel University London under Research Development Fund LBG194 and 2022/2023 Brunel Research Initiative and Enterprise Fund 12455

Magnetocaloric effect in itinerant electron metamagnetic systems La(Fe1-xCox)11.9Si1.1

The NaZn13-type compounds La(Fe1–xCox)11.9Si1.1 (x=0.04, 0.06, 0.08) were successfully synthesized, in which the Si content is the limit that can be reached by arc-melting technique. TC is tunable from 243 to 301 K with Co doping from x=0.04 to 0.08. Great magnetic entropy change S in a wide temperature range from ~230 to ~320 K has been observed. The adiabatic temperature change Tad upon changing magnetic field was also directly measured. Tad of sample x=0.06 reaches ~2.4 K upon a field change from 0 to 1.1 T. The temperature hysteresis upon phase transition is small, ~1 K, for all samples. The influence of Co doping on itinerant electron metamagnetic transition and magnetic entropy change is discussed. ©2005 American Institute of Physics.published_or_final_versio

Silicon-based spin and charge quantum computation

Silicon-based quantum-computer architectures have attracted attention because of their promise for scalability and their potential for synergetically utilizing the available resources associated with the existing Si technology infrastructure. Electronic and nuclear spins of shallow donors (e.g. phosphorus) in Si are ideal candidates for qubits in such proposals due to the relatively long spin coherence times. For these spin qubits, donor electron charge manipulation by external gates is a key ingredient for control and read-out of single-qubit operations, while shallow donor exchange gates are frequently invoked to perform two-qubit operations. More recently, charge qubits based on tunnel coupling in P$_2^+$ substitutional molecular ions in Si have also been proposed. We discuss the feasibility of the building blocks involved in shallow donor quantum computation in silicon, taking into account the peculiarities of silicon electronic structure, in particular the six degenerate states at the conduction band edge. We show that quantum interference among these states does not significantly affect operations involving a single donor, but leads to fast oscillations in electron exchange coupling and on tunnel-coupling strength when the donor pair relative position is changed on a lattice-parameter scale. These studies illustrate the considerable potential as well as the tremendous challenges posed by donor spin and charge as candidates for qubits in silicon.Comment: Review paper (invited) - to appear in Annals of the Brazilian Academy of Science

220 GHz Sparse Imaging with Multi-static Aperiodic Array

Research Development Fund of Brunel University London under Grant LBG194

Selecting electrical billing attributes: big data preprocessing improvements

The attribute selection is a very relevant activity of data preprocessing when discovering knowledge on databases. Its main objective is to eliminate irrelevant and/or redundant attributes to obtain computationally treatable issues, without affecting the quality of the solution. Various techniques are proposed, mainly from two approaches: wrapper and ranking. This article evaluates a novel approach proposed by Bradley and Mangasarian (Machine learning ICML. Morgan Kaufmann, Sn Fco, CA, pp. 82–90, 1998 [1]) which uses concave programming for minimizing the classification error and the number of attributes required to perform the task. The technique is evaluated using the electric service billing database in Colombia. The results are compared against traditional techniques for evaluating: attribute reduction, processing time, discovered knowledge size, and solution quality

Soliton pair creation in classical wave scattering

We study classical production of soliton-antisoliton pairs from colliding wave packets in (1+1)-dimensional scalar field model. Wave packets represent multiparticle states in quantum theory; we characterize them by energy E and particle number N. Sampling stochastically over the forms of wave packets, we find the entire region in (E,N) plane which corresponds to classical creation of soliton pairs. Particle number is parametrically large within this region meaning that the probability of soliton-antisoliton pair production in few-particle collisions is exponentially suppressed.Comment: 16 pages, 8 figures, journal version; misprint correcte

Evolution of Landau Levels into Edge States at an Atomically Sharp Edge in Graphene

The quantum-Hall-effect (QHE) occurs in topologically-ordered states of two-dimensional (2d) electron-systems in which an insulating bulk-state coexists with protected 1d conducting edge-states. Owing to a unique topologically imposed edge-bulk correspondence these edge-states are endowed with universal properties such as fractionally-charged quasiparticles and interference-patterns, which make them indispensable components for QH-based quantum-computation and other applications. The precise edge-bulk correspondence, conjectured theoretically in the limit of sharp edges, is difficult to realize in conventional semiconductor-based electron systems where soft boundaries lead to edge-state reconstruction. Using scanning-tunneling microscopy and spectroscopy to follow the spatial evolution of bulk Landau-levels towards a zigzag edge of graphene supported above a graphite substrate we demonstrate that in this system it is possible to realize atomically sharp edges with no edge-state reconstruction. Our results single out graphene as a system where the edge-state structure can be controlled and the universal properties directly probed.Comment: 16 pages, 4 figure