Climatic regions as an indicator of forest coarse and fine woody debris carbon stocks in the United States

<p>Abstract</p> <p>Background</p> <p>Coarse and fine woody debris are substantial forest ecosystem carbon stocks; however, there is a lack of understanding how these detrital carbon stocks vary across forested landscapes. Because forest woody detritus production and decay rates may partially depend on climatic conditions, the accumulation of coarse and fine woody debris carbon stocks in forests may be correlated with climate. This study used a nationwide inventory of coarse and fine woody debris in the United States to examine how these carbon stocks vary by climatic regions and variables.</p> <p>Results</p> <p>Mean coarse and fine woody debris forest carbon stocks vary by Köppen's climatic regions across the United States. The highest carbon stocks were found in regions with cool summers while the lowest carbon stocks were found in arid desert/steppes or temperate humid regions. Coarse and fine woody debris carbon stocks were found to be positively correlated with available moisture and negatively correlated with maximum temperature.</p> <p>Conclusion</p> <p>It was concluded with only medium confidence that coarse and fine woody debris carbon stocks may be at risk of becoming net emitter of carbon under a global climate warming scenario as increases in coarse or fine woody debris production (sinks) may be more than offset by increases in forest woody detritus decay rates (emission). Given the preliminary results of this study and the rather tenuous status of coarse and fine woody debris carbon stocks as either a source or sink of CO₂, further research is suggested in the areas of forest detritus decay and production.</p

The sperm factor: paternal impact beyond genes

The fact that sperm carry more than the paternal DNA has only been discovered just over a decade ago. With this discovery, the idea that the paternal condition may have direct implications for the fitness of the offspring had to be revisited. While this idea is still highly debated, empirical evidence for paternal effects is accumulating. Male condition not only affects male fertility but also offspring early development and performance later in life. Several factors have been identified as possible carriers of non-genetic information, but we still know little about their origin and function and even less about their causation. I consider four possible non-mutually exclusive adaptive and non-adaptive explanations for the existence of paternal effects in an evolutionary context. In addition, I provide a brief overview of the main non-genetic components found in sperm including DNA methylation, chromatin modifications, RNAs and proteins. I discuss their putative functions and present currently available examples for their role in transferring non-genetic information from the father to the offspring. Finally, I identify some of the most important open questions and present possible future research avenues

Effects of circadian disruption on physiology and pathology: from bench to clinic (and back)

Nested within the hypothalamus, the suprachiasmatic nuclei (SCN) represent a central biological clock that regulates daily and circadian (i.e., close to 24 h) rhythms in mammals. Besides the SCN, a number of peripheral oscillators throughout the body control local rhythms and are usually kept in pace by the central clock. In order to represent an adaptive value, circadian rhythms must be entrained by environmental signals or zeitgebers, the main one being the daily light?dark (LD) cycle. The SCN adopt a stable phase relationship with the LD cycle that, when challenged, results in abrupt or chronic changes in overt rhythms and, in turn, in physiological, behavioral, and metabolic variables. Changes in entrainment, both acute and chronic, may have severe consequences in human performance and pathological outcome. Indeed, animal models of desynchronization have become a useful tool to understand such changes and to evaluate potential treatments in human subjects. Here we review a number of alterations in circadian entrainment, including jet lag, social jet lag (i.e., desynchronization between body rhythms and normal time schedules), shift work, and exposure to nocturnal light, both in human subjects and in laboratory animals. Finally, we focus on the health consequences related to circadian/entrainment disorders and propose a number of approaches for the management of circadian desynchronization.Fil: Chiesa, Juan José. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Duhart, José Manuel. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Casiraghi, Leandro Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paladino, Natalia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bussi, Ivana Leda. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andrés. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Modelling the Grain Yield of Wheat in Irrigated Saline Environment with Foliar Potassium Fertilization

In the present study, an effort was made to calibrate and validate a crop model using the experiment generated data pertaining to growth and yield of wheat cultivars under irrigated saline environment using foliar potassium application. A field experiment was conducted at Water Technology Centre research farm, Indian Agricultural Research Institute, New Delhi, in split–split plot design during rabi 2011–2012 and 2012–2013 to generate data for simulation of FAO AquaCrop model. Two wheat cultivars (i.e. one salt tolerant KRL-1-4 and other salt susceptible HD 2894) under four salinity levels, viz, GW (1.7 dS m−1), 4, 8 and 12 dS m−1 were experimented under foliar and non-foliar treatments. AquaCrop model was calibrated using experiment data of rabi 2011–2012 and validated with data of rabi 2012–2013. The model evaluation parameters, viz, model efficiency (ME), index of agreement (d) and R 2 pertaining to grain yield of both wheat cultivars predicted by validated model were averaged to be 0.86, 0.95 and 0.96, respectively, under all treatment levels. Moreover, the simulated biomass yield of both the cultivars was with average values of ME, d and R 2 as 0.91, 0.97, and 0.93, respectively. However, model validation results for water productivity were 0.60, 0.82 and 0.93 for ME, d and R 2, respectively. It was observed that the AquaCrop model simulation for grain yield was better as compared to biomass and water productivity for all treatment levels. Validated model resulted in predicted grain yield of both wheat cultivars with low prediction error (i.e. 1.77–6.52%) up to 8 dS m−1, whereas at 12 dS m−1 salinity level, the prediction error increased and varied from 21.7 to 37.5%. Nonetheless, the FAO AquaCrop model can be used with acceptable accuracy for simulation of grain yield of wheat cultivars using saline irrigation up to 8 dS m−1 with foliar potassium fertilization