The Association of Coloproctology of Great Britain and Ireland consensus guidelines in emergency colorectal surgery

ACKNOWLEDGEMENTS Review and editing: S.R. Brown, Professor of Surgery, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK. Email [email protected]. Patient summary: R.G. Arnott, Retired Professor, Patient Liaison Group, Association of Coloproctology of Great Britain and Ireland, Royal College of Surgeons of England, London, UK. Email [email protected]. Delphi review: C.P. Macklin. BMedSci BM BS FRCS DM, Consultant Colorectal Surgeon, Mid Yorkshire Hospitals, UK. Email [email protected] reviewedPublisher PD

A robust system for RNA interference in the chicken using a modified microRNA operon

AbstractRNA interference (RNAi) provides an effective method to silence gene expression and investigate gene function. However, RNAi tools for the chicken embryo have largely been adapted from vectors designed for mammalian cells. Here we present plasmid and retroviral RNAi vectors specifically designed for optimal gene silencing in chicken cells. The vectors use a chicken U6 promoter to express RNAs modelled on microRNA30, which are embedded within chicken microRNA operon sequences to ensure optimal Drosha and Dicer processing of transcripts. The chicken U6 promoter works significantly better than promoters of mammalian origin and in combination with a microRNA operon expression cassette (MOEC), achieves up to 90% silencing of target genes. By using a MOEC, we show that it is also possible to simultaneously silence two genes with a single vector. The vectors express either RFP or GFP markers, allowing simple in vivo tracking of vector delivery. Using these plasmids, we demonstrate effective silencing of Pax3, Pax6, Nkx2.1, Nkx2.2, Notch1 and Shh in discrete regions of the chicken embryonic nervous system. The efficiency and ease of use of this RNAi system paves the way for large-scale genetic screens in the chicken embryo

Bank credit in the transmission of monetary policy: A critical review of the issues and evidence

The "credit view" emphasizes the impact of monetary policy on the amount and conditions of credit supplied by the banking sector as a main transmission channel. A review of the literature shows that the view that banks are in some sense special is widely accepted. However, whether the bank credit channel is an important part of the aggregate monetary transmission remains questionable. There is no evidence for credit rationing, at least not at the macroeconomic level. Many of the empirical results on the credit channel have alternative interpretations. Much of the debate on a bank credit channel appears to deal with effects of second-order importance.bank credit channel, monetary policy

On the Relationship between the Investment-Cashflow Sensitivity and the Degree of Financing Constraints

We investigate whether the investment-cash flow sensitivity is monotonic in the degree of financing constraints. By using a large panel of publicly traded non-financial U.K. firms, we show that the investment-cash flow sensitivity is neither monotonically increasing nor decreasing in the most common proxies of financing constraints; on the contrary, an inverse U-shaped relationship is observed. Robustness exercises show that the parameter of interest displays, to some extent, a monotonic behavior with respect to size only; however, in contrast with much of the relevant literature, it is found to be greater for larger firms, whose characteristics would hardly lead the researcher to classify them as more financially constrained. If taken as a whole, our findings suggest that higher investment-cash flow sensitivities may hardly be used as evidence of greater financial constraints.Investment cash flow sensitivity, Financial constraints, Internal funds, Capital market imperfections.

Structural Modelling of Financial Constraints on Investment: Where Do We Stand?

This paper surveys issues with respect to the structural modelling of econometric tests of investment facing financial constraints, to their link with firms data and asset prices, and to their consequences for macroeconomic modelling. The key issue is to provide conditions which support the interpretation of the sensitivity of investment to liquidity variables such as cash flow as a measure of financial constraints. The structural modelling of investment facing financial constraints is also limited by the structural modelling of the forces driving investment dynamics such as adjustment costs, which has not been so successful empirically.Investment, Financial Constraints, Structural models

Structural modelling of investment and financial constraints: Where do we stand?

This paper surveys issues with respect to the structural modelling of econometric tests of investment facing financial constraints, to their link with firms data and assets prices, and to their impact in macroeconomic modelling. The key issue is to ground much more the interpretation of the sensitivity of investment to liquidity variables such as cash flow as a measure of financial constraints. The structural modelling of investment facing financial constraints is also limited by the structural modelling of the force driving investment dynamics such as adjustment costs, which has not been so successful empirically.

Investment Spending in the Netherlands: The Impact of Liquidity and Corporate Governance

This paper examines the relation between cash flow, corporate governance and fixed-investment spending. In perfect capital markets we expect no systematic relationship. However, Myers and Majluf's (1984) asymmetric information hypothesis and Jensen's (1986) managerial discretion hypothesis present imperfections and predict a positive impact of cash flow on investment in fixed assets. Aspects of corporate governance play an important role in both theories. We measure the impact of cash flow on investment for a set of Dutch firms and aim to distinguish between the asymmetric information hypothesis and the managerial discretion hypothesis. Our findings show that cash flow is an important determinant of investment expenditures. The impact of cash flow is largest for firms with low growth opportunities suggesting that the managerial discretion hypothesis is most at work in the Dutch setting. We also discern that the impact of governance characteristics on both investment and the cash flow-sensitivity of investment differ between firms having low and high growth opportunities. This implies that governance affects the managerial discretion and asymmetric information hypotheses differently.investment;corporate liquidity;cash flow;corporate governance

A temperate former West Antarctic ice sheet suggested by an extensive zone of bed channels

Several recent studies predict that the West Antarctic Ice Sheet will become increasingly unstable under warmer conditions. Insights on such change can be assisted through investigations of the subglacial landscape, which contains imprints of former ice-sheet behavior. Here, we present radio-echo sounding data and satellite imagery revealing a series of ancient large sub-parallel subglacial bed channels preserved in the region between the Möller and Foundation Ice Streams, West Antarctica. We suggest that these newly recognized channels were formed by significant meltwater routed along the icesheet bed. The volume of water required is likely substantial and can most easily be explained by water generated at the ice surface. The Greenland Ice Sheet today exemplifies how significant seasonal surface melt can be transferred to the bed via englacial routing. For West Antarctica, the Pliocene (2.6–5.3 Ma) represents the most recent sustained period when temperatures could have been high enough to generate surface melt comparable to that of present-day Greenland. We propose, therefore, that a temperate ice sheet covered this location during Pliocene warm periods

Neoclassical vs Evolutionary Theories of Financial Constraints : Critique and Prospectus

Complicated neoclassical models predict that if investment is sensitive to current financial performance, this is a sign that something is "wrong" and is to be regarded as a problem for policy. Evolutionary theory, on the other hand, refers to the principle of "growth of the fitter" to explain investment-cash flow sensitivities as the workings of a healthy economy. In particular, I attack the neoclassical assumption of managers maximizing shareholder-value. Such an assumption is not a helpful starting point for empirical studies into firm growth. one caricature of neoclassical theory could be "Assume firms are perfectly efficient. Why aren't they getting enoug funding ?", whereas evolutionary theory considers that firms are forever struggling to grow. This essay highlights how policy guidelines can be framed by the initial modelling assumptions, even though these latter are often chosen with analytical tractability in mind rather than realism.Financial constraints, firm growth, evolutionary theory, neoclassical theory, investment.