57 research outputs found
Comparing timed-division multiplexing and best-effort networks-on-chip
Best-effort (BE) networks-on-chips (NOCs) are usually preferred over time-division multiplexed (TDM) NOCs in multi-core platforms because they are work-conserving and have lower (zero-load) latency. On the other hand, BE NOCs are significantly more expensive to implement than TDM NOCs because of their virtual channel buffers, allocators/arbiters, and (credit-based) flow control; functionality that a TDM NOC avoids altogether. The objective of this paper is to compare the performance of BE and TDM NOCs, taking hardware cost into consideration. The networks are compared using graphs showing average latency as a function of offered load. For the BE NOCs, we use the BookSim simulator, and for the TDM NOCs, we derive a queuing theory model and an associated TDM NOC simulator. Through experiments with both router architectures, packet length, link width, and different traffic patterns, we show that for the same hardware cost, a TDM NOC can provide higher bandwidth and comparable latency. We also show that the packet length is the most important factor affecting the TDM period, which again is the primary factor affecting latency. The best TDM NOC design for BE traffic uses single flit packets, wide links/flits, and a router with two pipeline stages: link and router traversal.publishedVersionPeer reviewe
Kan man lære at spise en by, eller kan man lære en by at spise?:BoxTowns Gastronaruimprojekt drømmer om at skabe maddannelse for borgere, foreninger og skoleelever
α7 And β2 Nicotinic Acetylcholine Receptor Subunits Form Heteromeric Receptor Complexes That Are Expressed In The Human Cortex And Display Distinct Pharmacological Properties
The existence of α7β2 nicotinic acetylcholine receptors (nAChRs) has recently been demonstrated in both the rodent and human brain. Since α7-containing nAChRs are promising drug targets for schizophrenia and Alzheimer\u27s disease, it is critical to determine whether α7β2 nAChRs are present in the human brain, in which brain areas, and whether they differ functionally from α7 nAChR homomers. We used α-bungarotoxin to affinity purify α7-containing nAChRs from surgically excised human temporal cortex, and found that α7 subunits co-purify with β2 subunits, indicating the presence of α7β2 nAChRs in the human brain. We validated these results by demonstrating co-purification of β2 from wild-type, but not α7 or β2 knock-out mice. The pharmacology and kinetics of human α7β2 nAChRs differed significantly from that of α7 homomers in response to nAChR agonists when expressed in Xenopus oocytes and HEK293 cells. Notably, α7β2 heteromers expressed in HEK293 cells display markedly slower rise and decay phases. These results demonstrate that α7 subunits in the human brain form heteromeric complexes with β2 subunits, and that human α7β2 nAChR heteromers respond to nAChR agonists with a unique pharmacology and kinetic profile. α7β2 nAChRs thus represent an alternative mechanism for the reported clinical efficacy of α7 nAChR ligands
Liquefaction of Lignosulfonate in Supercritical Ethanol Using Alumina-Supported NiMo Catalyst
Lignosulfonate was subjected to a
reductive catalytic degradation
in ethanol medium at 310 °C in the presence of alumina supported
NiMo catalysts and H2. The liquid and solid products were
analyzed with size exclusion chromatography (SEC), gas chromatography
mass spectrometry (GC–MS), two-dimensional gas chromatography
(GC × GC), heteronuclear single quantum coherence nuclear magnetic
resonance (HSQC NMR) and elemental analysis. The highest oil yield
and the lowest char yield obtained was 88 and 15 wt %, respectively.
The liquefied species were mainly dimers and oligomers with minor
yields of monomers. The catalyst was important for stabilization of
reactive intermediates either by hydrogenation or coupling with ethanol.
Simultaneous deoxygenation and desulfurization reactions took place
in the presence of the catalyst; the oxygen and sulfur content in
the oil fraction obtained after 4 h reaction time were 11.2 and 0.1
wt %, indicating considerable deoxygenation and desulfurization compared
to the lignosulfonate feedstock (O, 30.8 wt %; S, 3.1 wt %). The effect
of the reaction parameters such as temperature, reaction time and
catalyst mass was studied. It was observed that by increasing the
temperature from 260 to 310 °C the degradation increased, however,
the SEC analysis showed that the degradation progressed only to a
certain size range dimers to oligomers in the reaction temperatures
studied. Investigating the effect of reaction time of 1, 2, 3, and
4 h indicated that degradation, deoxygenation, desulfurization and
alkylation reactions progressed over time. The reusability of the
catalyst without any pretreatment was confirmed by an almost constant
oil yield in three repeated experiments with the same catalyst batch.
The results show that alumina supported NiMo catalysts are very promising
catalysts for conversion of lignosulfonate to liquid products
Graviditet og erhverv: Et deskriptivt epidemiologisk studie af graviditetsudfald og branchemæssig beskæftigelse
An evaluation of the National Patient Register. A study of validity of some abortion diagnoses
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