Offspring sex ratio of introduced red deer in Patagonia, Argentina after an intensive drought

Red deer (Cervus elaphus) introduced to Patagonia have reached high densities in the forest-steppe ecotone. Drought conditions during 1998/99 were suspected to impact subsequent reproductive performance. Necropsies of 50 adult females during winter 1999 revealed lowered pregnancy rates and lactation in 32% of non-pregnant as opposed to 0% among pregnant females. There were no signs of fetal resorptions or abortions. The fetal sex ratio (20m:8f) deviates significantly from unity, and mothers with female or male fetuses averaged 6,7 and 5,2 years, respectively (P=0.14). However, 90% of primiparous females (2,5 years old) had males, the following age class had all females, the middle age class (5-8 years old) had all males, and older females had equally male or female fetuses. These females were at borderline of body condition allowing conception and thus were at extremely low levels of condition during breeding. The male-biased fetal sex ratio contrasts reports of other studies that only females in best condition tend to have male-biased offspring. However, ambivalent results from other studies may stem from not having evaluated body fat reserves and reproductive tracts, or studies done during environmental conditions not extreme enough. The present results also indicate that red deer populations occur at densities where they can easily become food-limited through a singular environmental phenomenon such as a drought. Although recruitment rates would be drastically reduced through such temporary food shortage, red deer will recuperate rapidly and will continue to exert intensive pressure on the flora causing subsequent damage if population densities are not lowered through hunting.Fil: Fluck, Werner Thomas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Reservas corporales y tasa de preñez del ciervo colorado introducido en Patagonia (Argentina) después de un período de sequía

El ciervo rojo (Cervus elaphus) fue introducido en Patagonia en la década de 1920 y ha alcanzado densidades altas en ciertas áreas del ecotono entre el bosque y la estepa. Se especuló que las condiciones de severa sequía del verano-otoño de 1999 podían tener un efecto negativo sobre la reproducción del ciervo rojo. Las necropsias de 50 hembras adultas revelaron una tasa de preñez de solo 56%, comparado con un 98% en 1992–1998 o un 100% en 1996–1997 en otra población similar. La distribución de edades de hembras preñadas reflejó la importancia de no haber gestado durante el ciclo anterior. Las hembras primíparas de dos años tuvieron una tasa de preñez de 77%, mientras que ninguna de las hembras con crías lactantes estaba preñada. Normalmente, el mayor éxito reproductivo se observa en las clases de mediana edad, lo que reduce la probabilidad de preñez durante periodos de stress, lo cual se reflejó en este estudio en la distribución de edades de las hembras no-gestantes. Sin embargo, la circunferencia a la altura del pecho (como índice del tamaño corporal) no fue diferente entre las hembras gestantes y las no gestantes. Las reservas de grasa corporal estuvieron severamente agotadas en la mayoría de los animales, independientemente de su condición reproductiva. La relación entre crías y hembras adultas en el otoño siguiente fue de 30%, en comparación con 58% en 1991–1992. En la otra población, la relación fue de 28% en el otoño siguiente, indicando que el efecto de la sequía tuvo carácter regional. Los resultados sugieren que estas poblaciones de ciervo rojo tienen densidades a las cuales pueden experimentar fácilmente limitaciones de tipo nutricional debido a un fenómeno ambiental singular como un período de sequía. Aunque la tasa de reclutamiento se redujo drásticamente a través de la escasez de comida, el efecto podría ser temporario, hasta terminar la sequía, y los ciervos rojos podrían continuar ejerciendo una presión intensiva sobre la vegetación si no disminuyen las densidades de la población a través de la caza regular u otra forma de control.Red deer (Cervus elaphus) were introduced to Patagonia in the 1920´s and have reached high densities in certain areas of the forest-steppe ecotone. Severe drought conditions during summer/autumn of 1999 were suspected to have an impact on reproduction of red deer. Necropsies of 50 adult females revealed a pregnancy rate of only 56% as compared to 98% in 1992-98 or 100% in 1996/7 in a comparable population. The age distribution of pregnant females reflected the importance of not having been pregnant during the previous cycle. The primiparous  2 year-old females had a 77% pregnancy rate whereas none of  the lactating females were pregnant. Normally a higher reproductive success occurs for middle age classes, thereby reducing the chances of becoming pregnant during stress periods which was reflected in this study in the age distribution of non-pregnant females. Chest girths as an index of body size, however, were not different for pregnant and non-pregnant females. Body fat reserves were severely depleted in most animals irrespective of reproductive status. The calf-to-adult female ratio in the following autumn was 30% as compared to 58% in 1991/2. The ratio in a comparable population was 28% in the following autumn, indicating that the effect of the drought was regional. The results suggest that these red deer populations occur at densities where they can easily become food-limited through a singular environmental phenomenon such as a drought period. Although the recruitment rate was drastically reduced through such food shortage, the effect might be of short duration as the drought terminates and red deer may continue to exert intensive pressure on the flora causing subsequent damage if population densities are not lowered through continuous hunting or other control means.Fil: Fluck, Werner Thomas. Administración de Parques Nacionales. Parque Nacional ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Chronic Kidney Disease – Where Next? : Predicting Outcomes And Planning Care Pathways

Peer reviewedPublisher PD

The Defeasance of Control Rights

We analyze one frequently used clause in public bonds called covenant defeasance. Covenant defeasance allows the bond issuer to remove all of the bond's covenants by placing the remaining outstanding payments with a trustee in an escrow account to be paid out on schedule. Bond covenants are predominantly noncontingent, action-limiting covenants. By giving the issuer an option to remove covenants, noncontingent control rights can be made state-contingent even when no interim signals are available. We provide a theoretical justi cation for covenant defeasance and show empirically that such a clause allows for the inclusion of more covenants in public bond issues. In line with the model's prediction, our empirical analysis documents a 13-25 basis points premium for defeasible bonds. This premium amounts to an annual saving of about $1m per year, or$11m over the lifetime of an average bond.Bonds; Covenants; Defeasance; Renegotiation

Venture Capital Contracting and Syndication: An Experiment in Computational Corporate Finance

This paper develops a model to study how entrepreneurs and venture-capital investors deal with moral hazard, effort provision, asymmetric information and hold-up problems. We explore several financing scenarios, including first-best, monopolistic, syndicated and fully competitive financing. We solve numerically for the entrepreneur's effort, the terms of financing, the venture capitalist's investment decision and NPV. We find significant value losses due to holdup problems and under-provision of effort that can outweigh the benefits of staged financing and investment. We show that a commitment to later-stage syndicate financing increases effort and NPV and preserves the option value of staged investment. This commitment benefits initial venture capital investors as well as the entrepreneur.

Contingent Control Rights and Managerial Incentives: The Design of Long-term Debt

Enterprises, small or large, rely heavily on long-term financing arrangements to fund their operations. However, it has proved difficult for financial theory to justify the use of long-term contracts when the manager has the ability to divert or manipulate the cash flows, and when it is prohibitively costly for a third party, such as a court, to verify or prove any managerial wrongdoing. Why would investors enter into financial contracts that extend beyond the life of the firm's existing physical assets when such contracts rely on the manager to make repeated investments during the life of the contract? How can investors induce the manager to make these investments when such investments cannot be contracted upon? In this paper we show that with the appropriate design of the control rights longer-term debt contracts can become sustainable. In particular, investors are willing to hold long-term debt if they are granted (1) the right to dismiss the manager and to take over the company as a going concern upon default; or (2) the right to dismiss the manager and to extend the maturity of the debt in default. Interestingly, it is the threat of dismissal that induces management to comply with the contract but it is the investors' ability to extend the maturity of the debt in default that makes this threat credible. Empirical evidence reported by Gilson (1990, 1993), Gilson, John and Lang (1990), Franks and Torous (1993, 1994), Franks, Nyborg and Torous (1996), Franks and Sussman (1999) supports our view that creditors' right to dismiss manager and to take equity or to extend the maturity of the debt in default plays a key role in enforcing the repayment of debt. Once we established that long-term debt is sustainable, the natural question to ask is whether investors would be indifferent between long-term debt and outside equity or whether they would prefer one over the other. Despite the strong similarity of the control rights and the maturity of debt and equity, investors will not be indifferent between the two securities in our model. If a project can raise long-term debt it can also raise outside equity but the reverse is not true: there are projects that cannot issue debt but may still obtain outside equity financing. This is so because of the nature of the control rights. Since debtholders have contingent control rights, they cannot exercise control unless default has occurred. Hence, the manager can devise more profitable default strategies by planning his default ahead of time and milking the assets prior to default. Since contingent control rights allow the manager more opportunities for wealth transfer from investors off the equilibrium path than unconditional rights, long-term debt contracts must offer the manager substantially higher incentive payments in equilibrium than equity. Thus, a project aiming to secure longer-term debt financing must show evidence of higher expected profitability than one seeking equity financing