Temporary nutrient deficiency - a difficult case for diagnosis and prognosis by plant analysis

Plant analysis aims to either detect deficiency at the time of sampling (diagnosis) or predict its occurrence at a later stage of growth (prognosis). Its use is based on the presumption that the plant nutrient status will either be constant with plant age or follow a predictable pattern of change over time after sampling. However, a period of deficiency during plant growth followed by the recovery of nutrient uptake to satisfactory rates may cause an irreversible impairment of growth which plant analysis fails to diagnose or predict. Several cases are considered, each involving a temporary deficiency of, or interruption to nutrient supply. Such cases generally involve but are not restricted to micronutrient deficiency. For example, B deficiency impairs early seedling growth when seeds low in B are planted, even on B fertilised soils. Low B concentration in seeds diagnoses the subsequent impairment of seed germination or seedling establishment: however, leaf analysis after emergence does not. Similarly, Zn deficiency impairs early growth of transplanted oilseed rape (Brassica napus L.) seedlings and eventually depresses seed yield. However, leaf analysis during crop growth fails to diagnose a Zn deficiency. Finally, temporary B deficiency induced by low vapour pressure deficit or low soil water especially during reproductive development may depress yield markedly but remain difficult to diagnose by plant analysis. Strategies for diagnosing and predicting such temporary deficiencies are discussed including the measurement of environmental parameters such as pan evaporation or rainfall and their inclusion in multi‐variate regression models of plant response to nutrients

On the Kimmeridgian (Jurassic) succession of the Normandy coast, northern France

Kimmeridgian rocks crop out on the Normandy coast north and south of the Seine Estuary at Le Havre in a series of small foreshore and cliff exposures separated by beach deposits and landslips. A total thickness of about 45 m of richly fossiliferous strata is exposed, ranging from the base of the Baylei Zone to the middle part of the Eudoxus Zone. The sections are mostly unprotected by sea-defence works and are subject to rapid marine erosion and renewal. Taken together, the Normandy exposures currently provide a more complete section through the low and middle parts of the Kimmeridgian Stage than any natural English section, including those of the Dorset type area. Descriptions and a stratigraphical interpretation of the Normandy sections are presented that enable the faunal collections to be placed in their regional chronostratigraphical context. The Kimmeridgian succession at outcrop on the Normandy coast contains numerous sedimentary breaks marked by erosion, hardground and omission surfaces. Some of these are disconformities that give rise to rapid lateral variations in the succession: biostratigraphical studies need, therefore, to be carried out with particular care

Fantasies of war in Peake's uncollected verse

No abstract available

Hours Constraints Within and Between Jobs

In the empirical literature on labour supply, several models are developed to incorporate constraints on working hours. These models do not address the question to which extent working hours are constrained within and between jobs. In this paper I investigate the effect of individual changes in labour supply preferences on actual working hours. The availability of subjective information on the individual’s preferred working hours gives direct measures on the degree of adjustment of working hours within and between jobs. I take the potential endogeneity of the observed changes in labour supply preferences into account by using instrumental variables techniques. Using the Dutch Socio Economic Panel, I find for women who work in two consecutive years that the degree of adjustment of working hours within jobs is significantly smaller than between jobs. I also find that job mobility does not lead to complete adjustment in working hours, as the realized adjustment is significantly less than 100 percent of the preferred adjustment.labour supply;hours constraints;job mobility;subjective data

Detection of specific bacteria in water: implications of survival strategy

It is widely recognised that conventional culture techniques may underestimate true viable bacterial numbers by several orders of magnitude. The basis of this discrepancy is that a culture in or on media of high nutrient concentration is highly selective (either through ”nutrient shock” or failure to provide vital co-factors) and decreases apparent diversity; thus it is unrepresentative of the natural community. In addition, the non-culturable but viable state (NCBV) is a strategy adopted by some bacteria as a response to environmental stress. The basis for the non-culturable state is that cells placed in conditions present in the environment cannot be recultured but can be shown to maintain their viability. Consequently, these cells would not be detected by standard water quality techniques that are based on culture. In the case of pathogens, it may explain outbreaks of disease in populations that have not come into contact with the pathogen. However, the NCBV state is difficult to attribute, due to the failure to distinguish between NCBV and non-viable cells. This article will describe experiences with the fish pathogen Aeromonas salmonicida subsp. salmonicida and the application of molecular techniques for its detection and physiological analysis

Non-uniform wordlength delay lines for FIR filters

When FIR filters are designed floating point arithmetic is generally used. However when implemented on hardware such as ASICs, fixed point arithmetic must be used to minimise cost and power requirements. Research to minimise hardware costs has mainly focused on the quantization effects of fixed point wordlengths for the coefficients, multipliers and adders of FIR filters, but with the actual data delays assigned a uniform wordlength and essentially not optimised. This paper proposes that the wordlengths of the delay line can be non-uniform with a minimal increase in quantization noise for parallel implementation of FIR filters where there are differences in the magnitudes of the coefficients. A non-uniform delay line allows hardware savings in terms of delay register wordlengths, delay signal wordlengths and multiplier wordlengths. Results for an FIR design are presented which demonstrate the hardware savingswhen using a non-uniform wordlength delay lin

Adaptive digital signal processing Java teaching tool

This publication presents a JAVA program for teaching the rudiments of adaptive digital signal processing (DSP) algorithms and techniques. Adaptive DSP is on of the most important areas of signal processsing, and provides the core algorithmic means to implement applications ranging from mobile telephone speech coding, to noise cancellation, to communication channel equalization. Over the last 30 years adaptive digital signal processing has progressed from being a strictly graduate level advanced class in signal processing theory to a topic that is part of the core curriculum for many undergraduate signal processing classes. The JAVA applet presented in this publication has been devised for students to use in combination with lecture notes and/or one of the recognised textbooks such that they can quickly and conveniently simulate algorithms such as the LMS (least mean squares), RLS (recursive least squares) and so on in a variety of applications without requiring to write programs or scripts or using any special purpose software. By the very nature of the JAVA code therefore, the applet can be run from any browser, even over a low bandwidth modem connection

The response of stock prices to changes in weekly money and the discount rate

Money supply ; Stock - Prices ; Discount

The FOMC in 1985: reacting to declining M1 velocity

Federal Open Market Committee ; Money supply ; Velocity of money ; Monetary policy - United States