Tectonic implications of the Brawley earthquake swarm, Imperial Valley, California, January 1975

The Brawley earthquake swarm provided a unique opportunity for studying a highly interesting tectonic region. The swarm was most intense for a period of 4 days including 75 events with M_L between 3.0 and 4.7 with a spatial extent of 12 km. Precise relative hypocenters were obtained for 264 earthquakes (M_L ≧ 1.5) using a master event method to calibrate the USGS Imperial Valley array. These locations together with well-constrained focal mechanisms for 16 of the largest events suggest faulting on at least three distinct structures. Hypocentral depths ranged from 4 to 8 km, compared to a basement depth of about 6 km for this part of the Imperial Valley. The swarm began on a nearly vertical right-lateral fault striking N8°W (Brawley fault) about 8 km southeast of Brawley at a point which had experienced enhanced shallow seismicity during the preceding 4 days. The seismicity migrated bilaterally north and south from this point at a constant velocity of 0.5 km/hr terminating to the north on a steeply south dipping, N50°E-striking fault. This structure is on trend with splays associated with the northern end of ground breakage of the 1940 Imperial Valley earthquake. To the south the seismicity ended near the northern end of the 10 km of surface rupture mapped by R. V. Sharp, which continues on strike to a point near the Imperial fault. Tectonic interpretations include the transfer of right-lateral offset from the Imperial fault to the Brawley fault associated with the formation of a closed depression bounded on the west and east by these two faults

Multi-level, multi-party singlets as ground states and their role in entanglement distribution

We show that a singlet of many multi-level quantum systems arises naturally as the ground state of a physically-motivated Hamiltonian. The Hamiltonian simply exchanges the states of nearest-neighbours in some network of qudits (d-level systems); the results are independent of the strength of the couplings or the network's topology. We show that local measurements on some of these qudits project the unmeasured qudits onto a smaller singlet, regardless of the choice of measurement basis at each measurement. It follows that the entanglement is highly persistent, and that through local measurements, a large amount of entanglement may be established between spatially-separated parties for subsequent use in distributed quantum computation.Comment: Corrected method for physical preparatio

Entanglement in Valence-Bond-Solid States

This article reviews the quantum entanglement in Valence-Bond-Solid (VBS) states defined on a lattice or a graph. The subject is presented in a self-contained and pedagogical way. The VBS state was first introduced in the celebrated paper by I. Affleck, T. Kennedy, E. H. Lieb and H. Tasaki (abbreviation AKLT is widely used). It became essential in condensed matter physics and quantum information (measurement-based quantum computation). Many publications have been devoted to the subject. Recently entanglement was studied in the VBS state. In this review we start with the definition of a general AKLT spin chain and the construction of VBS ground state. In order to study entanglement, a block subsystem is introduced and described by the density matrix. Density matrices of 1-dimensional models are diagonalized and the entanglement entropies (the von Neumann entropy and Renyi entropy) are calculated. In the large block limit, the entropies also approach finite limits. Study of the spectrum of the density matrix led to the discovery that the density matrix is proportional to a projector.Comment: Published version, 80 pages, 8 figures; references update

A Reply to Cook and Oreskes on Climate Science Consensus Messaging

In their replies to our paper (Pearce et al., 2017), both Cook and Oreskes agree with our central point: that deliberating and mobilizing policy responses to climate change requires thinking beyond public belief in a scientific consensus. However, they both continue to defend consensus messaging, either because of ‘the dangers of neglecting to communicate the scientific consensus’ (Cook, 2017, p. 1) or because ‘“no consensus”…remains… a contrarian talking point’ (Oreskes, 2017, p. 1). Both highlight previously conducted market research by fossil fuel companies which suggested that scientific uncertainty provided a political weapon in fighting regulation, concluding that incorrect public perceptions of the scientific consensus weaken support for policy action (Oreskes, 2017, p. 2)

Manipulating quantum information by propagation

We study creation of bi- and multipartite continuous variable entanglement in structures of coupled quantum harmonic oscillators. By adjusting the interaction strengths between nearest neighbors we show how to maximize the entanglement production between the arms in a Y-shaped structure where an initial single mode squeezed state is created in the first oscillator of the input arm. We also consider the action of the same structure as an approximate quantum cloner. For a specific time in the system dynamics the last oscillators in the output arms can be considered as imperfect copies of the initial state. By increasing the number of arms in the structure, multipartite entanglement is obtained, as well as 1 to M cloning. Finally, we are considering configurations that implement the symmetric splitting of an initial entangled state. All calculations are carried out within the framework of the rotating wave approximation in quantum optics, and our predictions could be tested with current available experimental techniques.Comment: 9 pages, APS forma

Soil respiration in a northeastern US temperate forest: a 22‐year synthesis

To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and inter‐annual variations in soil respiration (Rs), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 site‐years of eddy‐covariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (Re). Rs was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of Rs to experimental manipulations mimicking aspects of global change or aimed at partitioning Rs into component fluxes ranged from −70% to +52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on Rs was transient, but in other cases the time series were not long enough to rule out long‐term changes in respiration rates. Inter‐annual variations in weather and phenology induced variation among annual Rs estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddy‐covariance sites, aboveground respiration dominated Re early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patterns—high apparent rates of respiration during winter and very low rates in mid‐to‐late summer—at the Environmental Measurement Site suggest either bias in Rs and Re estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hard‐to‐measure fluxes (e.g., wintertime Rs, unaccounted losses of CO2 from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of Re, and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this data‐rich analysis identifies important seasonal and experimental variations in Rs and Re and in the partitioning of Re above‐ vs. belowground

Prolongation of isovolumetric relaxation time as assessed by Doppler echocardiography predicts doxorubicin-induced systolic dysfunction in humans

AbstractA reasonably sensitive and specific noninvasive test for doxorubicin cardiotoxicity is needed. In addition, few data exist on the short- and long-term effects of doxorubicin on diastolic filling. To determine if pulsed Doppler indexes of diastolic filling could predict doxorubicin-induced systolic dysfunction, 26 patients (mean age 48 ± 12 years) were prospectively studied before receiving chemotherapy (control) and 3 weeks after obtaining cumulative doses of doxorubicin.In nine patients developing doxorubicin-induced systolic dysfunction (that is, a decrease in ejection fraction by ≥ 10 ejection fraction units to <55% the isovolumetric relaxation time was prolonged (from 66 ± 18 to 84 ± 24 ms, p < 0.05) after a cumulative doxorubicin dose of 100 to 120 mg/m2. This prolongation preceded a significant decrease in ejection fraction. Other Doppler indexes of filling were impaired after doxorubicin therapy but occurred simultaneously with the decrease in ejection fraction.A >37% increase in isovolumetric relaxation time was 78% (7 of 9) sensitive and 88% (15 of 17) specific for predicting the ultimate development of doxorubicin-induced systolic dysfunction. In 15 patients studied 1 h after the first treatment, doxorubicin enhanced Doppler indexes of filling and shortened isovolumetric relaxation time. In 22 patients, indexes of filling remained impaired and isovolumetric relaxation time was prolonged 3 months after the last doxorubicin dose.In conclusion, doxorubicin-induced systolic dysfunction is reliably predicted by prolongation of Doppler-derived isovolumetric relaxation time. Early after administration, doxorubicin enhances filling and isovolumetric relaxation time. The adverse effects of doxorubicin on both variables persist at least 3 months after cessation of treatment

Soil respiration in a northeastern US temperate forest: a 22‐year synthesis

To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and inter‐annual variations in soil respiration (Rs), we analyzed more than 100,000 individual measurements of soil respiration from 23 studies conducted over 22 years at the Harvard Forest in Petersham, Massachusetts, USA. We also used 24 site‐years of eddy‐covariance measurements from two Harvard Forest sites to examine the relationship between soil and ecosystem respiration (Re). Rs was highly variable at all spatial (respiration collar to forest stand) and temporal (minutes to years) scales of measurement. The response of Rs to experimental manipulations mimicking aspects of global change or aimed at partitioning Rs into component fluxes ranged from −70% to +52%. The response appears to arise from variations in substrate availability induced by changes in the size of soil C pools and of belowground C fluxes or in environmental conditions. In some cases (e.g., logging, warming), the effect of experimental manipulations on Rs was transient, but in other cases the time series were not long enough to rule out long‐term changes in respiration rates. Inter‐annual variations in weather and phenology induced variation among annual Rs estimates of a magnitude similar to that of other drivers of global change (i.e., invasive insects, forest management practices, N deposition). At both eddy‐covariance sites, aboveground respiration dominated Re early in the growing season, whereas belowground respiration dominated later. Unusual aboveground respiration patterns—high apparent rates of respiration during winter and very low rates in mid‐to‐late summer—at the Environmental Measurement Site suggest either bias in Rs and Re estimates caused by differences in the spatial scale of processes influencing fluxes, or that additional research on the hard‐to‐measure fluxes (e.g., wintertime Rs, unaccounted losses of CO2 from eddy covariance sites), daytime and nighttime canopy respiration and its impacts on estimates of Re, and independent measurements of flux partitioning (e.g., aboveground plant respiration, isotopic partitioning) may yield insight into the unusually high and low fluxes. Overall, however, this data‐rich analysis identifies important seasonal and experimental variations in Rs and Re and in the partitioning of Re above‐ vs. belowground

Porcine associated Salmonella Typhimuirum DT120: use of PFGE and MLVA in a putative outbreak investigation

In November 2006 a cluster of Salmonella Typhimurium DT120 in the North East of England was putatively associated with the consumption of pork. At the same time cases of illness in Denmark were associated with this Salmonella type, and a EU alert was issued to determine the type of S. Typhimurium DT120 identified. Isolates from the UK and Denmark were compared on the basis of antibiogram, Pulsed Field Gel Electrophoresis (PFGE) and Multi-Locus-Variable number andem repeat Analysis (MLVA or VNTR) to identify the S. Typhimurium DT120 type and results were compared electronically. Isolates from England had the resistance profile ApSSuT (ampicillin, streptomycin, sulfamethoxazole and tetracycline), VNTR profile (171-244-316-0-487) and with the distinct PFGE type (STYMXB.0083). Isolates from Denmark were resistant to Ap (ampicillin) only, had the VNTR type (171-270-324-0-490) and a PFGE type distinct from England (STYMXB.0010). It was therefore possible to confirm that the isolates from England and Denmark were not identical. These results have verified the significance of VNTR in outbreak investigations for S. Typhimurium and have demonstrated how new molecular strategies may be used to supplement existing methods such as PFGE to enable the accurate and rapid comparison of isolates from different countries