A Complementary Resistive Switch-based Crossbar Array Adder

Redox-based resistive switching devices (ReRAM) are an emerging class of non-volatile storage elements suited for nanoscale memory applications. In terms of logic operations, ReRAM devices were suggested to be used as programmable interconnects, large-scale look-up tables or for sequential logic operations. However, without additional selector devices these approaches are not suited for use in large scale nanocrossbar memory arrays, which is the preferred architecture for ReRAM devices due to the minimum area consumption. To overcome this issue for the sequential logic approach, we recently introduced a novel concept, which is suited for passive crossbar arrays using complementary resistive switches (CRSs). CRS cells offer two high resistive storage states, and thus, parasitic sneak currents are efficiently avoided. However, until now the CRS-based logic-in-memory approach was only shown to be able to perform basic Boolean logic operations using a single CRS cell. In this paper, we introduce two multi-bit adder schemes using the CRS-based logic-in-memory approach. We proof the concepts by means of SPICE simulations using a dynamical memristive device model of a ReRAM cell. Finally, we show the advantages of our novel adder concept in terms of step count and number of devices in comparison to a recently published adder approach, which applies the conventional ReRAM-based sequential logic concept introduced by Borghetti et al.Comment: 12 pages, accepted for IEEE Journal on Emerging and Selected Topics in Circuits and Systems (JETCAS), issue on Computing in Emerging Technologie

A Truth Universally Acknowledged: Beyond Wealth And Status At Archanes-Phourni

In the Pre- and Protopalatial periods, Minoan burial practices were communal, interactive, and sustained, creating complex tomb assemblages that span several hundred years. Small-scale taphonomic analyses of mortuary contexts indicate that secondary treatments of human remains were variable and frequent while large-scale regional studies suggest greater diversity among Early Minoan (EM) and Middle Minoan (MM) communities than previously believed. These nuanced approaches to variability, however, have not been fully realized at the mid-range, intra-site scale. Diversity in tomb architecture and object assemblages has continually been interpreted as evidence of hierarchical social structure and increasing social complexity before the appearance of the Minoan palaces, often ignoring other aspects of these contexts that contradict this interpretation. This dissertation focuses on social interaction rather than social structure, and proposes a methodology for considering complex tomb assemblages and intra-site variability using the well-known site of Archanes-Phourni as a case study. It provides a detailed, contextual re-analysis of the 23 communal and long-lived burial contexts dating from EM IIA to MM II (ca. 2700-1700 BCE), highlighting chronological and spatial variability related to changing burial practices and distinct group identities. Using quantitative and qualitative analytical methods, and drawing on contemporary theories of time, materiality, personhood, and value, this work offers an interpretation of the diverse and interactive burial practices at Archanes-Phourni at multiple scales. Contextual analysis of these tomb assemblages indicates that there was significant variety in spatial structure, methods of interment, and object deposition but that these individually variable practices occurred alongside long-lived, communally shared traditions. The frequent interactions with burial deposits that served to maintain connections between the living and the dead throughout the Prepalatial and into the Protopalatial period, diminished in MM II, suggesting a new approach to burial and to the cemetery

A mixed method study investigating the impact of talking about patients’ internet use on patient-reported outcomes

This study aims to propose and test a model that provides a more comprehensive understanding of the impact of discussing online health information on patient outcomes. By combining survey data (N = 160) and qualitative analysis of video recordings of consultations (N = 165) with structural equation modeling, this study explores: (1) whether patients and health-care providers talk about online medical information and (2) the impact of talking about online medical information on patient outcomes (patient satisfaction, recall of medical information, and medication adherence). Results show that more than half of the patients searched online prior to their consultation. In about half of these consultations (46.81%), the online information was discussed. Patients were more satisfied with the consultation if the online information was discussed during the consultation. Moreover, patient satisfaction was positively related to recall of medical information, but only in patients with whom the online information was discussed. There was no effect found on medication adherence. Results of this study demonstrate the importance of talking about online information during a consultation for improving patient outcomes. Implications for research are discussed

Language standardization in sociolinguistics and international business: Theory and practice across the table

This chapter addresses the issue of language standardization from two perspectives, bringing together a theoretical perspective offered by the discipline of sociolinguistics with a practical example from international business. We introduce the broad concept of standardization and embed the study of language standardization in the wider discussion of standards as a means of control across society. We analyse the language policy and practice of the Danish multinational, Grundfos, and use it as a “sociolinguistic laboratory” to “test” the theory of language standardization initially elaborated by Einar Haugen to explain the history of modern Norwegian. The table is then turned and a model from International Business by Piekkari, Welch and Welch is used to illuminate recent Norwegian language planning. It is found that the Grundfos case works well with the Haugen model, and the International Business model provides a valuable practical lesson for national language planners, both showing that a “comparative standardology” is a valuable undertaking. More voices “at the table” will allow both theory and practice to be further refined and for the role of standards across society to be better understood

Temporal patterns of biological dimethylsulfide (DMS) consumption during laboratory-induced phytoplankton bloom cycles

Phytoplankton bloom cycles were followed for 9 d in two 20 l carboy mesocosms filled with water from the offshore plume of Mobile Bay Alabama, USA, and incubated under fluorescent light. One of the blooms was enriched by addition of nitrate+phosphate (+nutrients), and both blooms were used to study how dimethylsulfide (DMS) concentrations and biological consumption varied over the bloom cycles. Peaks of algal biomass (15-22 µg chlorophyll a l-1) in the blooms were followed within 1 d by peaks of the DMS precursor, particulate dimethylsulfoniopropionate (DMSPp; 100-140 nM). DMS concentrations increased rapidly during the early bloom, rising from 1 nM on Day 1 up to 12 nM in the unamended carboy and up to 17 nM in the +nutrient carboy on Day 6. Maximum values for DMS concentrations, DMS consumption rates (as measured with 35S-DMS), and bacterial production were observed during the early decline of phytoplankton biomass. DMS consumption rates were initially 0.8 nM d-1 and increased to 3.1 nM d-1 in the unamended carboy and to 9.1 nM d-1 in the +nutrient carboy. Rate constants for DMS consumption (0.25-0.95 d-1) initially decreased as DMS concentrations increased, resulting in longer turnover times for DMS during the peak and early decline of the blooms. Assimilation of DMS-sulfur by bacterioplankton accounted for 4-22% of the total DMS consumption and higher rates of DMS assimilation occurred in the +nutrients bloom. Despite a bloom and decline of total heterotrophic bacterial abundances, bacterial community composition at the major phylogenetic group level remained relatively constant in both blooms, although the alpha proteobacteria showed a temporal increase in abundance in the +nutrient carboy. The concentration ratios of DMS:chlorophyll a and DMS:DMSP displayed non-linear, sigmoidal patterns over the bloom cycles and these ratios were not substantially affected by the nutrient amendment. Our results demonstrate that uncoupling of DMS production and biological consumption can occur early in a bloom cycle, causing DMS concentrations to rise significantly before biological consumption responds to draw down the DMS

Applicability of Well-Established Memristive Models for Simulations of Resistive Switching Devices

Highly accurate and predictive models of resistive switching devices are needed to enable future memory and logic design. Widely used is the memristive modeling approach considering resistive switches as dynamical systems. Here we introduce three evaluation criteria for memristor models, checking for plausibility of the I-V characteristics, the presence of a sufficiently non-linearity of the switching kinetics, and the feasibility of predicting the behavior of two anti-serially connected devices correctly. We analyzed two classes of models: the first class comprises common linear memristor models and the second class widely used non-linear memristive models. The linear memristor models are based on Strukovs initial memristor model extended by different window functions, while the non-linear models include Picketts physics-based memristor model and models derived thereof. This study reveals lacking predictivity of the first class of models, independent of the applied window function. Only the physics-based model is able to fulfill most of the basic evaluation criteria.Comment: 9 pages; accepted for IEEE TCAS-

Polarization measurements on irradiated ammonia

The polarization characteristics of ammonia irradiated at liquid helium temperatures and subsequently used in a scattering experiment are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87408/2/488_1.pd

Mapping Charge-Transfer Excitations in Bacteriochlorophyll Dimers from First Principles

Photoinduced charge-transfer excitations are key to understand the primary processes of natural photosynthesis and for designing photovoltaic and photocatalytic devices. In this paper, we use Bacteriochlorophyll dimers extracted from the light harvesting apparatus and reaction center of a photosynthetic purple bacterium as model systems to study such excitations using first-principles numerical simulation methods. We distinguish four different regimes of intermolecular coupling, ranging from very weakly coupled to strongly coupled, and identify the factors that determine the energy and character of charge-transfer excitations in each case. We also construct an artificial dimer to systematically study the effects of intermolecular distance and orientation on charge-transfer excitations, as well as the impact of molecular vibrations on these excitations. Our results provide design rules for tailoring charge-transfer excitations in Bacteriochloropylls and related photoactive molecules, and highlight the importance of including charge-transfer excitations in accurate models of the excited-state structure and dynamics of Bacteriochlorophyll aggregates