Atherosclerosis in coronary, aortic, and sciatic arteries from wild male turkeys (Meleagris gallopavo silvestris)

Heart, aorta, and sciatic arteries were collected from 157 wild male turkeys (Meleagris gallopavo silvestris) by hunters in 9 states during the spring 1983 and 1984 hunting seasons. In descending order of extent and severity, intimal vascular changes were observed in the left sciatic artery, aorta at the celiac region, cranial abdominal portion of the aorta, sciatic bifurcation, caudal abdominal portion of the aorta, coronary arteries, and thoracic portion of the aorta. Only the aorta from the celiac region and right sciatic artery had significant differences (P less than 0.05) among turkeys from various locations. Turkeys from Indiana had significantly (P less than 0.05) larger plaque scores in the celiac region than did those from Alabama, Missouri, and South Carolina. Turkeys from Indiana also had significantly (P less than 0.05) greater plaque scores in the right sciatic artery than did turkeys from Arkansas. When all tissues were considered, tissues from turkeys from Michigan had the highest plaque scores and those from Iowa had the lowest. Plaque scores for turkeys from Michigan were significantly (P less than 0.05) higher overall (including all blood vessels) than were plaque scores for turkeys from Alabama, Arkansas, Iowa, and South Carolina. Few significant (P less than 0.05) correlations were detected among plaque scores in turkeys from within states of origin (geographic location). Also, only a few significant (P less than 0.05) correlations were determined between age or body weight and atherosclerosis for blood vessels from turkeys within various states.     

Episodic-like memory in rats: is it based on when or how long ago?

Recent experiments with rats suggest that they show episodic-like or what-where-when memory for a preferred food found on a radial maze. Although memory for when a salient event occurred suggests that rats can mentally travel in time to a moment in the past, an alternative possibility is that they remember how long ago the food was found. Three groups of rats were tested for memory of previously encountered food. The different groups could use only the cues of when, how long ago, or when + how long ago. Only the cue of how long ago food was encountered was used successfully. These results suggest that episodic-like memory in rats is qualitatively different from human episodic memory.     

Selective differentiation of neural progenitor cells by high-epitope density nanofibers

Neural progenitor cells were encapsulated in vitro within a three-dimensional network of nanofibers formed by self-assembly of peptide amphiphile molecules. The self-assembly is triggered by mixing cell suspensions in media with dilute aqueous solutions of the molecules, and cells survive the growth of the nanofibers around them. These nanofibers were designed to present to cells the neurite-promoting laminin epitope IKVAV at nearly van der Waals density. Relative to laminin or soluble peptide, the artificial nanofiber scaffold induced very rapid differentiation of cells into neurons, while discouraging the development of astrocytes. This rapid selective differentiation is linked to the amplification of bioactive epitope presentation to cells by the nanofibers.     

Greenhouse gas fluxes in an open air humidity manipulation experiment

Air moisture is one of the main factors causing the greenhouse effect, but humidity has not been thoroughly studied at the ecosystem level. In 2006 a free-air humidity manipulation (FAHM) facility was established in Estonia to investigate the effect of humidity on the performance of two tree species—silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.). The trial is located on an Endogleyic Planosol of former arable land and offers the opportunity to change relative air humidity through controlled artificial misting and drying. We measured the CO₂, CH₄ and N₂O emission from the FAHM system using closed chamber and gas-chromatograph techniques from July 2009 to October 2010. Measurements were carried out once a month in three humidification (h) plots and in three control (c) plots. The vegetation period was rainy in 2009, but the next summer was relatively dry. The dry summer interacted better with the humidification. The CO₂ flux decreased when the air moisture was higher than in the control plots. The soil acted as a sink for methane. Less CH₄ was oxidized in the soil with increased humidity. Emission of N₂O did not correlate with air humidity, although one could observe a clear tendency that there was a smaller N₂O flux during the period with increased humidity. Expectedly, CO₂ emission and CH₄ consumption demonstrated strong positive correlations with soil temperature.     

Long-term study of above- and below-ground biomass production in relation to nitrogen and carbon accumulation dynamics in a grey alder (Alnus incana (L.) Moench) plantation on former agricultural land

In the Northern and Baltic countries, grey alder is a prospective tree species for short-rotation forestry. Hence, knowledge about the functioning of such forest ecosystems is critical in order to manage them in a sustainable and environmentally sound way. The 17-year-long continuous time series study is conducted in a grey alder plantation growing on abandoned agricultural land. The results of above- and below-ground biomass and production of the 17-year-old stand are compared to the earlier published respective data from the same stand at the ages of 5 and 10 years. The objectives of the current study were to assess (1) above-ground biomass (AGB) and production; (2) below-ground biomass: coarse root biomass (CRB), fine root biomass (FRB) and fine root production (FRP); (3) carbon (C) and nitrogen (N) accumulation dynamics in grey alder stand growing on former arable land. The main results of the 17-year-old stand were as follows: AGB 120.8 t ha^?1; current annual increment of the stem mass 5.7 t ha year^?1; calculated CRB 22.3 t ha^?1; FRB 81 ± 10 g m^?2; nodule biomass 31 ± 19 g m^?2; fine root necromass 11 ± 2 g m^?2; FRP 53 g DM m^?2 year^?1; fine root turnover rate 0.54 year^?1; and fine root longevity 1.9 years. FRB was strongly correlated with the stand basal area and stem mass. Fine root efficiency was the highest at the age of 10 years; at the age of 17 years, it had slightly reduced. Grey alder stand significantly increased N and C_org content in topsoil. The role of fine roots for the sequestration of C is quite modest compared to leaf litter C flux.     

Lake trout growth is sensitive to spring temperature in southwest Alaska lakes

In high‐latitude lakes, air temperature is an important driver of ice cover thickness and duration, which in turn influence water temperature and primary production supporting lake consumers and predators. In lieu of multidecadal observational records necessary to assess the response of lakes to long‐term warming, we used otolith‐based growth records from a long‐lived resident lake fish, lake trout (Salvelinus namaycush), as a proxy for production. Lake trout were collected from seven deep, oligotrophic lakes in Lake Clark National Park and Preserve on in southwest Alaska that varied in the presence of marine‐derived nutrients (MDN) from anadromous sockeye salmon (Oncorhynchus nerka). Linear mixed‐effects models were used to partition variation in lake trout growth by age and calendar‐year and model comparisons tested for a mean increase in lake trout growth with sockeye salmon presence. Year effects from the best mixed‐effects model were subsequently compared to indices of temperature, lake ice, and regional indices of sockeye salmon escapement. A strong positive correlation between annual lake trout growth and temperature suggested that warmer springs, earlier lake ice break‐up, and a longer ice‐free growing season increase lake trout growth via previously identified bottom‐up increases in production with warming. Accounting for differences in the presence or annual escapement of sockeye salmon with available data did not improve model fit. Collectively with other studies, the results suggest that productivity of subarctic lakes has benefitted from warming spring temperatures and that temperature can synchronise otolith growth across lakes with and without sockeye salmon MDN.     

Prediction of nutritive values,morphology and agronomic characteristics in forage maize using two applications of NIRS spectrometry

This study evaluates nutritive, morphological and agronomic characteristics of forage maize predicted by using a high-quality near-infrared (NIR) spectrometer and an NIR hyperspectral-imaging technique using partial least squares (PLS) regression models. The study includes 132 samples of dried milled whole-plant homogenates of forage maize with variation in maturity, representing two growing seasons, three locations in Sweden and three commercial maize hybrids. The samples were measured by a classical sample cup NIR spectrometer and by a pushbroom hyperspectral-imaging instrument. The spectra and a number of variables (crude protein, CP, neutral detergent fibre, starch, water soluble carbohydrates (WSC) and organic matter digestibility), morphological variables (leaves, stems & ears) and crop yield were used to make PLS calibration models. Using PLS modelling allowed the determination of how well maize variables can be predicted from NIR spectra and a comparison of the two types of instruments. Most examined variables could be determined equally well, by both instruments, but the pushbroom technique gave slightly better predictions and had higher analytical capacity. Predictions of CP, starch, WSC and the proportions of ears in the maize gave robust. The findings open new possibilities to further utilise the technology in plant breeding, crop management, modelling and forage evaluation.