3,669 research outputs found
Properties and strains of additional DNA repair-defective mutants in known and new genes of Neurospora crassa.
Some time ago, a number of mutants hypersensitive to MMS (methyl methane-sulfonate) were induced in Neurospora to obtain further types of DNA repair-deficient mutants; e.g., rec^- types not yet identified in Neurospora (meiotic-defective mutants generally are hyperrec ; Schroeder 1986 Curr. Genet. 10:381-387)
Transparent In-Circuit Assertions for FPGAs
Commonly used in software design, assertions are statements placed into a design to ensure that its behaviour matches that expected by a designer. Although assertions apply equally to hardware design, they are typically supported only for logic simulation, and discarded prior to physical implementation. We propose a new HDL-agnostic language for describing latency-insensitive assertions and novel methods to add such assertions transparently to an already placed-and-routed circuit without affecting the existing design. We also describe how this language and associated methods can be used to implement semi-transparent exception handling. The key to our work is that by treating hardware assertions and exceptions as being oblivious or less sensitive to latency, assertion logic need only use spare FPGA resources. We use network-flow techniques to route necessary signals to assertions via spare flip-flops, eliminating any performance degradation, even on large designs (92% of slices in one test). Experimental evaluation shows zero impact on critical-path delay, even on large benchmarks operating above 200MHz, at the cost of a small power penalty
Delay-Bounded Routing for Shadow Registers
The on-chip timing behaviour of synchronous circuits can be quantified at run-time by adding shadow registers, which allow designers to sample the most critical paths of a circuit at a different point in time than the user register would normally. In order to sample these paths precisely, the path skew between the user and the shadow register must be tightly controlled and consistent across all paths that are shadowed. Unlike a custom IC, FPGAs contain prefabricated resources from which composing an arbitrary routing delay is not trivial. This paper presents a method for inserting shadow registers with a minimum skew bound, whilst also reducing the maximum skew. To preserve circuit timing, we apply this to FPGA circuits post place-and-route, using only the spare resources left behind. We find that our techniques can achieve an average STA reported delay bound of ±200ps on a Xilinx device despite incomplete timing information, and achieve <1ps accuracy against our own delay model
Recommended from our members
The Source of Enhanced Cognitive Control in Bilinguals: Evidence From Bimodal Bilinguals
Bilinguals often outperform monolinguals on nonverbal tasks that require resolving conflict from competing alternatives. The regular need to select a target language is argued to enhance executive control. We investigated whether this enhancement stems from a general effect of bilingualism (the representation of two languages) or from a modality constraint that forces language selection. Bimodal bilinguals can, but do not always, sign and speak at the same time. Their two languages
involve distinct motor and perceptual systems, leading to weaker demands on language control. We compared the performance of 15 monolinguals, 15 bimodal bilinguals, and 15 unimodal bilinguals on a set of flanker tasks. There were no group differences in accuracy, but unimodal
bilinguals were faster than the other groups; bimodal bilinguals did not differ from monolinguals. These results trace the bilingual advantage in cognitive control to the unimodal bilingual’s experience controlling two languages in the same modality
The influence of microgravity on invasive growth in Saccharomyces cerevisiae
This study investigates the effects of microgravity on colony growth and the morphological transition from single cells to short invasive filaments in the model eukaryotic organism Saccharomyces cerevisiae. Two-dimensional spreading of the yeast colonies grown on semi-solid agar medium was reduced under microgravity in the Sigma 1278b laboratory strain but not in the CMBSESA1 industrial strain. This was supported by the Sigma 1278b proteome map under microgravity conditions, which revealed upregulation of proteins linked to anaerobic conditions. The Sigma 1278b strain showed a reduced invasive growth in the center of the yeast colony. Bud scar distribution was slightly affected, with a switch toward more random budding. Together, microgravity conditions disturb spatially programmed budding patterns and generate strain-dependent growth differences in yeast colonies on semi-solid medium
Recommended from our members
Lifelong Bilingualism Maintains White Matter Integrity in Older Adults
Previous research has shown that bilingual speakers have higher levels of cognitive control than comparable monolinguals, especially at older ages. The present study investigates a possible neural correlate of this behavioral effect. Given that white matter (WM) integrity decreases with age in adulthood, we tested the hypothesis that bilingualism is associated with maintenance of WM in older people. Using diffusion tensor imaging, we found higher WM integrity in older people who were lifelong bilinguals than in monolinguals. This maintained integrity was measured by fractional anisotropy (FA) and was found in the corpus callosum extending to the superior and inferior longitudinal fasciculi. We also hypothesized that stronger WM connections would be associated with more widely distributed patterns of functional connectivity in bilinguals. We tested this by assessing the resting-state functional connectivity of frontal lobe regions adjacent to WM areas with group differences in FA. Bilinguals showed stronger anterior to posterior functional connectivity compared to monolinguals. These results are the first evidence that maintained WM integrity is related to lifelong naturally occurring experience; the resulting enhanced structural and functional connectivity may provide a neural basis for “brain reserve.
Efektivitas Serbuk Sargassum Polycystum Sebagai Antibakteri Pada Ikan Lele (Clarias SP.) Selama Penyimpanan Dingin
Ikan lele merupakan ikan air tawar yang diminati oleh masyarakat. Ikan lele mengandung nutrisi tinggi dan merupakan ikan yang berlendir, dan lendir merupakan salah satu media pertumbuhan yang baik untuk bakteri. Serbuk S. polycystum merupakan rumput laut coklat yang mengandung senyawa bioaktif yang berfungsi sebagai antibakteri. Penelitian ini bertujuan untuk mengetahui kandungan senyawa bioaktif yang ada pada serbuk S. polycystum dan kemampuan serbuk S. polycystum sebagai antibakteri pada ikan lele (Clarias sp.). Materi yang digunakan dalam penelitian ini adalah sebuk S. polycystum dan ikan lele (Clarias sp.). Metode penelitian yang digunakan adalah experimental laboratories dengan menggunakan Rancangan Acak Lengkap (RAL) faktorial dengan 2 faktor yaitu konsentrasi serbuk S. polycystum (0%, 3%, 6% dan 9%) dan lama penyimpanan (hari ke-0, hari ke-4, hari ke-8, dan hari ke-12). Rendemen serbuk S. polycystum sebesar 51,3 %, kandungan fenol 0,23 %, flavonoid 0,10 %, tanin 0,66 % dan saponin 0,64 %. Rendemen serbuk S. polycystum yang ditambahkan pada ikan lele yang disimpan pada suhu dingin menunjukkan bahwa perbedaan penambahan konsentrasi sebuk S. polycystum dan lama penyimpanan memberikan pengaruh nyata terhadap nilai TPC, nilai TVBN, nilai pH serta nilai organoleptik (p < 0,05). Konsentrasi terbaik pada penelitian ini adalah 6% dengan nilai TPC pada hari ke- 12 yaitu 1,3 x 105 CFU/g, nilai TVBN 20,63 mgN/100g, nilai pH sebesar 6,96 dan nilai organoleptik ikan lele konsentrasi 6% masih layak konsumsi
Multiple-inlet BIPV/T Modeling: Wind Effects and Fan Induced Suction
AbstractBuilding Integrated Photovoltaic/Thermal (BIPV/T) collectors take up the role of energy and heat production, while acting as a rain-screen cladding. A multiple inlet BIPV/T system counters the effect of high temperature stratification on the PV layer, by enhancing the convection inside the air channel with the introduction of more than one openings for the intake of fresh air that break up the surface boundary layer. To investigate the uniformity of heat extraction from the PV panels, the fluid mechanics of the system are studied separately from the thermal effects. A numerical flow distribution model, which incorporates wind effects, is introduced for the optimal design of multiple inlet systems so as to have flow rates through each inlet that maximize the heat extracted from the PV panels
Aquaporin 1a Expression in Gill, Intestine, and Kidney of the Euryhaline Silver Sea Bream
This study aimed to investigate the effects of chronic salinity acclimation, abrupt salinity transfer, and cortisol administration on aquaporin 1 (AQP1) expression in gill, intestine, and kidney of silver sea bream (Sparus sarba). An AQP1a cDNA was cloned and found to share 83–96% amino acid sequence identity with AQP1 genes from several fish species. Tissue distribution studies of AQP1a mRNA demonstrated that it was expressed in gill, liver, intestine, rectum, kidney, heart, urinary bladder, and whole blood. Semi-quantitative RT-PCR analysis was used to measure AQP1a transcript abundance in sea bream that were acclimated to salinity conditions of 0, 6, 12, 33, 50, and 70 ppt for 1 month. The abundance of gill AQP1a transcript was highest in sea bream acclimated to 0 ppt whereas no differences were found among 0–50 ppt groups. For intestine, the highest AQP1a transcript amounts were found in sea bream acclimated to 12 and 70 ppt whereas the transcript abundance of kidney AQP1a was found to be unchanged amongst the different salinity groups. To investigate the effects of acute salinity alterations on AQP1a expression, sea bream were abruptly transferred from 33 to 6 ppt. For intestine AQP1a levels were altered at different times, post transfer, but remained unchanged in gill and kidney. To study the effects of cortisol on AQP1a expression, sea bream were administered a single dose of cortisol followed by a 3-day acclimation to either 33 or 6 ppt. The findings from this experiment demonstrated that cortisol administration resulted in alterations of AQP1a transcript in gill and intestine but not in kidney
- …