We expect that many-core microprocessors will push performance per chip from the 10 gigaflop to the 10 teraflop range in the coming decade. To support this increased performance, memory and inter-core bandwidths will also have to scale by orders of magnitude. Pin limitations, the energy cost of electrical signaling, and the non-scalability of chip-length global wires are significant bandwidth impediments. Recent developments in silicon nanophotonic technology have the potential to meet these off-and on-stack bandwidth requirements at acceptable power levels.Corona is a 3D many-core architecture that uses nanophotonic communication for both inter-core communication and off-stack communication to memory or I/O devices. Its peak floating-point performance is 10 teraflops. Dense wavelength division multiplexed optically connected memory modules provide 10 terabyte per second memory bandwidth. A photonic crossbar fully interconnects its 256 low-power multithreaded cores at 20 terabyte per second bandwidth. We have simulated a 1024 thread Corona system running synthetic benchmarks and scaled versions of the SPLASH-2 benchmark suite. We believe that in comparison with an electrically-connected many-core alternative that uses the same on-stack interconnect power, Corona can provide 2 to 6 times more performance on many memoryintensive workloads, while simultaneously reducing power.

Human-associated microbial communities comprise not only complex mixtures of bacterial species, but also mixtures of conspecific strains, the implications of which are mostly unknown since strain level dynamics are underexplored due to the difficulties of studying them. We introduce the Strain Genome Explorer (StrainGE) toolkit, which deconvolves strain mixtures and characterizes component strains at the nucleotide level from short-read metagenomic sequencing with higher sensitivity and resolution than other tools. StrainGE is able to identify nearest known references and find variants for multiple conspecific strains within a sample at relative abundances below 0.1% in typical metagenomic datasets.

Aim: To compare the efficacy and tolerability of olsalazine sodium with enteric‐coated mesalazine in inducing endoscopic remission in patients with mild to moderate active ulcerative colitis. Patients and methods: Patients with mild to moderate active ulcerative colitis were randomized to receive either olsalazine sodium, 3 g/day (n = 88), or mesalazine, 3 g/day (n = 80), for up to 12 weeks. Results: Of the patients treated with olsalazine sodium, 52.2% achieved endoscopic remission, compared with 48.8% of patients treated with mesalazine. This difference was not significant (P = 0.67). There was a non‐significant trend for patients with left‐sided colitis or a more severe endoscopic grade to achieve remission if they were treated with olsalazine sodium than if they were treated with mesalazine. Both treatments were comparable with respect to clinical activity index and an investigator’s global assessment. Seventy patients reported one or more adverse events; adverse events were seen in 45% of olsalazine sodium‐treated patients and in 36% of mesalazine‐treated patients. Eleven patients treated with olsalazine sodium and nine patients treated with mesalazine withdrew from the study because of adverse events. One patient treated with olsalazine sodium compared with two treated with mesalazine stopped treatment because of diarrhoea. Serious adverse events occurred in three patients treated with olsalazine sodium and in four treated with mesalazine. Conclusion: Therapeutic effectiveness and tolerance to the treatment did not differ between olsalazine sodium, 3 g/day, and mesalazine, 3 g/day, in inducing endoscopic remission in patients with mild to moderate active ulcerative colitis within 12 weeks of treatment.

We investigate patch selection strategies of hosts and parasitoids in heterogeneous environments. Previous theoretical work showed that when host traits vary among patches, coevolved populations of hosts and parasitoids make congruent choices (i.e., hosts and parasitoids preferentially select the same patches) and exhibit direct density dependence in the distribution of percent parasitism. However, host-parasitoid systems in the field show a range of patterns in percent parasitism, while behavioral studies indicate that hosts and parasitoids can exhibit contrary choices (i.e., hosts avoid patches favored by the parasitoid). We extend previous theory by permitting life-history traits of the parasitoid as well as the host to vary among patches. Our analysis implies that in coevolutionarily stable populations, hosts preferentially select patches that intrinsically support higher host equilibrium numbers (i.e., the equilibrium number achieved by hosts when both populations are confined to a single patch) and that parasitoids preferentially select patches that intrinsically support higher parasitoid equilibrium numbers (i.e., the equilibrium number achieved by the parasitoids when both populations are confined to a patch). Using this result, we show how variation in life-history traits among patches leads to contrary or congruent choices or leads to direct density dependence, inverse density dependence, or density independence in the distribution of percent parasitism. In addition, we determine when populations playing the coevolutionarily stable strategies are ecologically stable. Our analysis shows that heterogeneous environments containing patches where the intrinsic rate of growth of the host and the survivorship rate of the parasitoid are low result in the coevolved populations exhibiting contrary choices and, as a result, promote ecological stability.

To determine whether common carotid artery blood flow measured with an ultrasonic flow transducer would predict brain blood flow in fetal sheep, we measured unilateral common carotid artery blood flow and compared this to simultaneous measurements of total brain blood flows made by radioisotope-labelled microsphere techniques. We studied anaesthetized, exteriorized fetal sheep with intact umbilical circulation after ligation of extracranial, extracerebral arteries and placement of a common carotid artery flow transducer; five fetuses at 120 d gestation had 19 total comparison measurements. As measured by microsphere technique, mean basal blood flow during undisturbed conditions to regional brain areas were similar to normal values reported for the exteriorized ovine fetus; these flows were highly correlated to fetal PaCO2 and successfully varied over a wide range (total brain 9.1-200.4 ml/min/100g and total cortex 6.1-153.1 ml/min/100g) in subsequent experimental conditions of hypercapnia or occluded blood flow. Blood flow as measured by flow transducer significantly correlated (P < or = 0.01) with microsphere measurements of blood flow to total brain (r = 0.56) and total cortex (r = 0.62); regional flow to cerebellum (r = 0.70) and thalamus (r = 0.60) also correlated to transducer measurements. Stronger correlations were observed at low-flow conditions to total brain (r = 0.83) and to total cortex (r = 0.90). As measured by microsphere technique, right and left cortical blood flows were highly correlated (P = 0.0001, r = 0.97), indicating that the flow transducer or surgical manipulation did not disturb the distribution of cerebral blood flow. The mean values for zero flow reference of the transducer were < 1.5% of mean basal flow values. It is concluded that the common carotid artery flow transducer technique developed in this study provides an accurate prediction of blood flow to total brain and total cortex over a wide range of values in fetal sheep. This technique provides a methodologic advantage to sequential experimental interventions and may prove advantageous to studies of fetal sheep cerebral circulation.