Effect of osmotic potential of activator solution and temperature on viability and vigour of wheat seed

Experiment was conducted to investigate if seed priming with polyethylene glycol (PEG) activator solutions affects the viability and vigour of deteriorating wheat (Triticum aestivum L. cv. Caxton) seed lot. Seeds were subjected to PEG priming solutions with varying osmotic potentials (-1, -2, -3 MPa) at temperatures of 15 or 20°C for 6, 12, 18 or 24 h and compared to the non-primed control. Highest germination percentage at first and final count, length of plumule and dry weight of seedling were all associated with Treatment 1 MPa/20°C/6 h (92%, 94%, 9.2 cm, 0.0133 mg, respectively) compared to the control (82.5%, 86%, 7.8 cm, 0.0112 mg, respectively). The best values of coefficient of velocity of germination (CVG), mean germination time (MGT) and germination rate index (GRI) were associated with Treatment 2 MPa/15°C/24 h. There were significant interactions between the factors under study and whilst most positive effects decreased with incubation time the opposite was true at 15°C Treatment 2 MPa where an initial decrease in germination after 6 h was restored with longer incubation times. Significant correlations were found between most of the characteristics under study although these did not always account for a high percentage of variation but CVG and MGT were very highly correlated. It was concluded that, 6 h in Treatment 1 MPa PEG at a temperature of 20°C resulted in significantly improved germination percentage whilst 24 h Treatment 2 MPa at 15°C was optimal for the highest CVG and MGT. The highest speed of germination was not associated with the highest germination percentage

On Verifying Causal Consistency

Causal consistency is one of the most adopted consistency criteria for distributed implementations of data structures. It ensures that operations are executed at all sites according to their causal precedence. We address the issue of verifying automatically whether the executions of an implementation of a data structure are causally consistent. We consider two problems: (1) checking whether one single execution is causally consistent, which is relevant for developing testing and bug finding algorithms, and (2) verifying whether all the executions of an implementation are causally consistent. We show that the first problem is NP-complete. This holds even for the read-write memory abstraction, which is a building block of many modern distributed systems. Indeed, such systems often store data in key-value stores, which are instances of the read-write memory abstraction. Moreover, we prove that, surprisingly, the second problem is undecidable, and again this holds even for the read-write memory abstraction. However, we show that for the read-write memory abstraction, these negative results can be circumvented if the implementations are data independent, i.e., their behaviors do not depend on the data values that are written or read at each moment, which is a realistic assumption.Comment: extended version of POPL 201

Segregation and precipitation of Er in Ge

Although Er-doped Genanomaterials are attractive for photonic applications, very little is known about the basic properties of Er in Ge. Here, the authors study the annealing behavior of Geimplanted with keV Er ions to doses resulting in ≲1at.% of Er. Large redistribution of Er, with segregation at the amorphous/crystalline interface, starts at ≳500°C, while lower temperatures are required for material recrystallization. However, even at 400°C, Er forms precipitates. The concentration of Er trapped in the bulk after recrystallization decreases with increasing temperature but is independent of the initial bulk Er concentration for the range of ion doses studied here.Work at the ANU was supported by the ARC

An Audit of 6 years of Oral and Maxillofacial Surgical Conditions admitted for Interventional Treatment at Muhimbili National Hospital, Dar es Salaam – Tanzania

Background: The world wide pattern of OMFS conditions has been rarely reported despite its significance in the head and neck medicine; maxillofacial trauma and tumors. The main objective of this study was to audit oral and maxillofacial surgical (OMFS) conditions admitted for interventional treatment at Muhimbili National Hospital. Methods: Patients presenting to the OMFS unit with oral and maxillofacial pathological conditions between January 2003 - January 2009 were studied prospectively. Data for analysis were obtained from the daily operation list and includes age, sex, location, diagnosis of the pathological lesion, surgical procedure and date of procedure. Results: During the study period, the unit offered specialized services to 454 patients. Among them, 222 were males and 232 females. The mean age of the patients was 31.7 and the range was 79 years. Patient aged 21-30 years were mostly affected. Of the pathological lesions attended, benign tumors were the most common 255(56.2%) followed by fractures 58(12.8%), cysts 46(10.1%), malignant tumors 36(7.9%) and chronic infections 17(3.7%). Of the 255 cases of benign tumors 155(60.8%) were located on the mandible and 64 (25.1%) on the maxilla. Malignant tumors were 36 cases in which 11(30.6%) were located on the mandible. Maxillofacial fractures accounted 58 cases in which 31(53.4%) cases were located on the mandible. Cysts were 46 cases of which 17(37%) were located on the floor of the mouth, 10(21.7%) on the mandible and 7(15.2%) on the maxilla. Tumor excision was the commonest procedure performed 119(26.2%), followed by Tumor excision + reconstruction 89(19.6%), ORIF+IMF 51(11.2%), Fistulectomy 45(9.9%), Tumor enucleation 45(9.9%), Wide surgical excision 27(5.9%), Sinusectomy 16(3.5%) and Sequestrectomy 15(3.3%). Conclusion: There is a significant burden of OMFS conditions attended at MNH. We suggest that the government enhance the state of medical infrastructure in the local hospitals in terms of manpower and facilities for the diagnosis and treatment of simpler OMFS disease as well as timely referral on to regional center for the more complex issues. This will reduce the burden of OMF conditions experienced by this hospital and improve OMF services country wide

Proximate and Heavy Metals Compositions of Some Commercial Fish Feeds available in Keffi Metropolis, Nasarawa State

The nutrient balance of feed influences its utilization and growth in fish. Proximate and heavy metals examinations were carried out on three different fish feed samples obtained from commercially available fish feed shops in Keffi metropolis and were labeled A, B, and C. The sealed samples were taken to the laboratory, ground using a mortar and pestle and kept in an airtight container for subsequent chemical analysis. The results of the proximate analysis shows that the moisture content, ash content, crude protein, crude lipid, crude fibre and carbohydrate content range from, 3.17% - 7.50%, 9.39% - 11.61%, 37.85% - 48.90%, 5.00% - 13.33%, 2.53% - 6.00% and 21.31% - 30.78% respectively. The estimated levels of heavy metals analysed ranges from 0.35mg/kg - 0.61 mg/kg, 0.27mg/kg - 0.44 mg/kg, 1.15 mg/kg - 1.47 mg/kg, 0.02 mg/kg - 0.44 mg/kg, 3.15 mg/kg - 3.25 mg/kg and 0.40 mg/kg - 0.50 mg/kg for Cu, Cr, Co, Cd, Ni and Pb respectively. The concentrations of the heavy metals determined are in order of Ni > Co > Cu > Pb > Cr > Cd. The results of the proximate analysis obtained are in close argument with that obtained in the literature which ranges from 10.06% - 10.38%, 5.33% - 9.45%, 8.512% - 24.40%, 3.20% - 12.73%, 5.00% - 13.00% and 25.89% - 52.65% respectively. For the heavy metals, it ranges from 0.0579mg/kg - 0.0023mg/kg, 0.0002mg/kg - 0.0005mg/kg, 0.01mg/kg - 0.37mg/kg, 1.22mg/kg - 4.71mg/kg and 0.06mg/kg - 0.68mg/kg for Cu, Cr, Co, Cd, Ni and Pb respectively. It is therefore concluded that all the fish feed samples analysed contain the required nutrients in required proportions declared by the manufacturers and the regulatory guide lines. The heavy metals concentrations and proximate compositions obtained are within the certified limits as regulated by WHO, SON and FAO

Correlated Markov Quantum Walks

We consider the discrete time unitary dynamics given by a quantum walk on $\Z^d$ performed by a particle with internal degree of freedom, called coin state, according to the following iterated rule: a unitary update of the coin state takes place, followed by a shift on the lattice, conditioned on the coin state of the particle. We study the large time behavior of the quantum mechanical probability distribution of the position observable in $\Z^d$ for random updates of the coin states of the following form. The random sequences of unitary updates are given by a site dependent function of a Markov chain in time, with the following properties: on each site, they share the same stationnary Markovian distribution and, for each fixed time, they form a deterministic periodic pattern on the lattice. We prove a Feynman-Kac formula to express the characteristic function of the averaged distribution over the randomness at time $n$ in terms of the nth power of an operator $M$. By analyzing the spectrum of $M$, we show that this distribution posesses a drift proportional to the time and its centered counterpart displays a diffusive behavior with a diffusion matrix we compute. Moderate and large deviations principles are also proven to hold for the averaged distribution and the limit of the suitably rescaled corresponding characteristic function is shown to satisfy a diffusion equation. An example of random updates for which the analysis of the distribution can be performed without averaging is worked out. The random distribution displays a deterministic drift proportional to time and its centered counterpart gives rise to a random diffusion matrix whose law we compute. We complete the picture by presenting an uncorrelated example.Comment: 37 pages. arXiv admin note: substantial text overlap with arXiv:1010.400