Mocarabe: High-Performance Time-Multiplexed Overlays for FPGAs

Coarse-grained reconfigurable array (CGRA) overlays can improve dataflow kernel throughput by an order of magnitude over Vivado HLS on Xilinx Alveo U280. This is possible with a combination of carefully floorplanned high-frequency (645 - 768 MHz Torus, 788 - 856 MHz Mesh, 583 - 746 MHz BFT) design and a scalable, communication-aware compiler. Our CGRA architecture supports configurable Processing Element (PE) functionality supported by a configurable number of communication channels to match application demands. Compared to recent FPGA overlays like 4×4 ADRES and HyCUBE implementations in CGRA-ME, our design operates at a faster clock frequency by up to 3.4×, while scaling to an orders-of-magnitude larger array size of 19×69 on Xilinx Alveo U280. We propose a novel topology agnostic ILP placer that formulates the CGRA placement problem into an ILP problem. Our ILP placer optimizes placement regardless of topology and even for non-linear objective functions by using pre-computed placement costs as inputs to the ILP problem formulation. Using the ILP placer reduces placement quadratic wirelength up to 37% compared to the commonly used simulated annealing approach but increases runtime from less than a minute to hours. Our communication-aware compiler targets HLS objectives such as initiation interval (II) and minimizes communication cost using an integer linear programming (ILP) formulation. Unlike SDC schedulers in FPGA HLS tools, we treat data movement as a first-class citizen by encoding the space and time resources of the communication network in the ILP formulation. Given the same constraints on operational resources as Vivado HLS, we can retain our target II and achieve up to 9.2× higher frequency. We compare Torus and Mesh topologies, and show Mesh has less latency per area compared to Torus for the same benchmarks

Temperature and water fluctuations southern Caspian Sea

A special temperature fluctuation exists in waters of Southern Caspian Sea. A depth survey of up to 100 m indicates that there are two thermal phenomena annually. One thermal phenomenon occurs in summer and autumn, and the other one in winter and spring. The least dissolved oxygen concentration at various depths was recorded in a depth of 100 m and was 7 mg/l. This is an indication of good mixing of lake strata because of two cold cycles in winter and spring

A Case Report of Topiramate-induced Acute Myopia

Acute myopia following use of some drugs is a relatively rare condition. Topiramate prescribed for seizure prophylaxis is one of these drugs. In this paper a case of acute transient myopia after taking topiramate is reported. The reported patient is a 28-year old woman who had no history of any eye disease. Following consumption of topiramate pill for one week, she had found blurred vision since one day prior to the admission. A complete ocular examinations revealed acute bilateral myopia. This disease was resolved about 48 hours after discontinuation of topiromate. Due to the wide spectrum of indications for the administration of Topiramate, neurologists and psychiatrists should be aware of its ocular side effects. In conclusion, ocular complications following this drug should be taken seriously and be subjected to ophthalmic counsaltation. Keywords: Topiramate, Myopia, Drug side effect

Changes of atmospheric water vapour isotopes in the Arctic at the interface with sea ice and open ocean

Evaporation from the increasingly ice-free Arctic ocean causes moistening of the atmosphere and serves as an unprecedent water source for the Northern Hemisphere. Atmospheric transport of moisture and its interaction with the other Arctic hydrological compartments can be tracked by primary and secondary water isotope parameters. We present observations of atmospheric humidity, δ18O, δD and d-excess, obtained from a cavity-ring-down spectrometer installed on RV Polarstern and operated continuously during the MOSAiC expedition. The dataset reveals a clear seasonal cycle of the atmospheric water vapour; positive correlation is found both with local specific humidity and air temperature. The comparison of synoptical events, characterized by abrupt isotopic fluctuations, with simultaneous observations from land-based Arctic stations indicates a strong influence of sea ice coverage on the isotopic signal. For an in-depth understanding of the isotopic changes, the observations are compared to results of an isotope-enhanced ECHAM6 atmosphere simulation. The model-data comparison assesses the capability of this state-of-the-art AGCM to capture the first-order evaporation/condensation processes and their seasonal evolution. However, a systematic overestimation of winter values and overall decreased variability of modeled values is found. Investigation of such discrepancies may help to identify deficits in the representation of the fine-scale exchange processes characterizing the central-Arctic water cycle

Isotopic traits of the Arctic water cycle

The Arctic hydrological cycle undergoes rapid and pronounced changes, including marine and terrestrial ice loss, increased atmospheric humidity, shifting ocean circulation regimes, and changes in the magnitude and frequency of extreme weather events. Stable water isotopes (δ18O, δ2H) and the secondary parameter d-excess can be used to trace the processes within this new evaporative system including the potential feedback of them into the global climate system. However, characteristics of δ18O, δ2H and d-excess and the processes governing them are yet to be quantified across the Arctic due to a lack of long-term empirical data. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition provided a unique opportunity to collect, analyze, and synthesize discrete samples of the different hydrological compartments in the central Arctic, covering a complete seasonal cycle over the course one year. These observations can lead to a new insight into coupled climate processes operating in the Arctic. Here, we present the isotopic traits of more than 1,900 discrete samples (i.e., seawater, sea ice, snow, brine, frost flower, lead ice, ridge ice). We found that: (i) average seawater δ18O of -1.7‰ conforms to observed and modelled isotopic traits of the Arctic Ocean with more depleted seawater closer to the north pole in winter and relatively enriched seawater in lower latitudes in spring; (ii) second year ice is relatively depleted compared to first year ice with average δ18O values of -3.1‰ and -0.7‰, respectively. This might be due to post-depositional exchange processes with snow; (iii) snow has the most depleted isotopic signature among all compartments (mean δ18O=-15.1‰) and a gradual enrichment trend in snow profiles from top to bottom might be partially due to sublimation of deposited snow. Our dataset provides an unprecedented description of the present-day isotopic composition of the Arctic water covering a complete seasonal cycle. We try to assess the relative contribution of snow, sea ice, leads, and melt ponds spatially and temporally on regional and local moisture in the Arctic. This will ultimately contribute to resolve the linkages between sea ice, ocean, and atmosphere during critical transitions from frozen ocean to open water conditions

Atmospheric water vapour isotopes in the Arctic at the interface with sea ice and open ocean

Due to the recent and severe downtrend in sea ice coverage, Arctic-derived moisture serves as new, increasingly important, water source for the northern hemisphere. Feedback and exchange processes between the different hydrological compartments of the Arctic might be tracked by stable water isotopologues (H216O, H218O, HD16O). This is possible as evaporative sources, phase changes and transport history have a specific imprint on the isotopic compositions. The MOSAiC drift experiment offered the unique possibility to tackle the main hydrological processes occurring in the Central Arctic, covering a complete seasonal cycle, including the understudied Arctic winter. A Cavity Ring Down Spectrometer (CRDS) was installed on board of RV Polarstern and atmospheric humidity, δ18O, δD and d-excess were observed continuously from October 2019 to October 2020. Simultaneously, isotopic changes of water vapour have been measured by international partners at several land-based Arctic stations. A first analysis of the Polarstern isotopic vapour dataset reveals a range of 30‰ (min=-48.4; max=-11.4; mean=-32.4) variations in δ18Ο of atmospheric water vapour. A clear seasonal cycle with the most depleted values occurring in the dry and cold winter months and increasingly enriched values in spring, peaking in August is noticed. Strong, positive correlation is found with both local specific humidity (r2 = 0.87) and air temperature (r2=0.81). Several short-term events on synoptical time scales with abrupt fluctuations in the isotopic composition are detected throughout the entire dataset, especially during the freeze up phase (Oct-Nov) and the transition from frozen conditions to summer melt (Apr-Jun). Preliminary comparison of the Polarstern data with measurements from different Arctic stations indicates a strong influence of sea ice coverage on the isotopic signal. For an in-depth understanding of the observed isotopic changes, we quantitatively compare the measured isotopic signatures with model results from an ECHAM6 atmosphere simulation, which includes explicit water isotope diagnostics. For this simulation, pressure and temperature fields have been nudged to ERA5 data. The model-data comparison assesses the capability of this state-of-the-art AGCM to capture the first-order evaporation/condensation processes and their seasonal evolution. However, both a systematic overestimation of winter values and overall decreased variability of modeled isotope values as compared to the observation is found. Investigation of such discrepancies may help to identify deficits in the representation of the fine-scale exchange processes characterizing the central-Arctic water cycle

Improving Quality and Operational Performance of Service Organizations: An Empirical Analysis Using Repeated Cross-Sectional Data of U.S. Firms

Research in quality management has provided new insights and directions on how to incorporate quality principles into organizational, operational, and policy decisions. However, most research into quality management has focused on manufacturing firms, which differ from service organizations in their structural and organizational characteristics, thus limiting the value of the findings for service organizations and highlighting the need for further research to assess quality practices in service organizations. In addition, whether quality management practices can provide sustainable quality results for service organizations is overlooked in the literature, primarily due to the lack of availability of reliable and valid data. This had led to inconsistent research findings, which limits theory development and managerial relevance of quality management for service organizations. Building upon the contingency theory of quality management, we examine the determinants of quality results in service organizations and determine the magnitude of the impacts of quality excellence programs on customer satisfaction and operational results in service organizations on a more detailed level. We use repeated cross-sectional data of 16 years from the Baldrige Quality Award program. The results show that information, analysis, and knowledge management is a significant predictor of quality and operational results, and management of process quality and human resource (HR) management significantly influence customer focus and satisfaction, controlling for the firms’ year. We also find that HR management has the strongest impact on customer focus and satisfaction in service organizations, followed by the management of process quality. In addition, the quality and operational improvements resulting from quality management implementation diminish over time in service enterprises. This article provides insights for service organizations and policymakers to enhance service quality and operational performance in service organizations

The isotopic composition of water vapour in the Central Arctic during the MOSAiC campaign: local versus distant-moisture sources.

The Arctic atmosphere has undergone a process of moistening during the past decades. The loss of sea ice has led to enhanced transfer of heat and moisture from the ocean to the lower atmosphere, while strengthening of cyclonic events has enhanced the poleward transport of moisture from lower latitudes. Eventually, the increased humidity of the Arctic air masses serves today as a new, increasingly important source of moisture for the northern hemisphere. Still, to date, the relative contributions of local evaporation versus distant-moisture sources remains uncertain, as well as the processes responsible for exchanges within and between the hydrological compartments of the Arctic. Such uncertainties limit our ability to understand the importance of the Arctic water cycle to global climate change and to project its future. In this study we use atmospheric water vapour isotopes to investigate the origin of the Arctic moisture and assess whether and which relevant changes occur within the coupled ocean-sea ice-atmosphere system (i.e., sea ice, sea water, snow, melt ponds). Stable isotopologues of water (HDO, H218O) have different saturation vapour pressures and molecular diffusivity coefficients in air. These differences lead to isotopic fractionation during each phase change of water, making water isotopes a powerful tracer of the Arctic hydrological cycle. Water vapour humidity, delta-18O, and delta-D have been measured continuously by a Picarro L2140i Cavity Ringdown Spectrometer installed onboard research vessel Polarstern during the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition, which took place in the Central Arctic Ocean from October 2019 to September 2020. Our measurements depict a clear seasonal cycle and a strong and significant covariance of delta-18O and delta-D with air temperature and specific humidity. At the synoptic time scale the dataset is characterized by the occurrence of events associated with humidity peaks and abrupt isotopic excursions. We use statistical analysis and backwards trajectories to i) identify the origin of the air masses and the relative contributions of distant vs. locally sourced moisture, and ii) illustrate the isotopic fingerprint of these two distinct moisture contributors and discuss on the source-to-sink processes leading to their differences. Further, the MOSAiC observations are compared to an ECHAM6 simulation, nudged to ERA5 reanalysis data and enabled for water isotope diagnostics. The model-data comparison makes it possible to explore the spatial representativeness of our observations and assess whether the model can correctly simulate the observed isotopic changes. In the future, our observations may serve as a benchmark to test the parametrization of under(mis-)represented fractionation processes such as snow sublimation, evaporation from leads and melt ponds. Our study provides the very first isotopic characterization of the Central Arctic moisture throughout an entire year and contributes to disentangling the influence of local evaporative processes versus large-scale vapour transport on the Arctic moistening