Solid state microelectronics tolerant to radiation and high temperature

The 300 C electronics technology based on JFET thick film hybrids was tested up to 10 to the 9th power rad gamma (Si) and 10 to the 15th power neutrons/sq cm. Circuits and individual components from this technology all survived this total dose although some devices required 1 hour of annealing at 200 or 300 C to regain functionality. This technology used with real time annealing should function to levels greater than 10 to the 10th power rad gamma and 10 to the 16th power n/sq cm

Canine Dominance Aggression

Each year, millions of dogs are taken to humane shelters across the United States. Of these dogs, it has been estimated that 15-20 million of them are euthanized. The majority of these animals are taken to shelters for some sort of behavioral problem, and by far, the most common behavioral problem found in dogs is aggressiveness. Canine aggression can be defined as an inappropriate threat, challenge, or attack by a dog against another dog, animal, or person in a given situation. It is important to realize that not all canine aggression is inappropriate-remember, one of the reasons dogs were originally domesticated was for protection. When a dog attacks visitors or family members, however, it is an inappropriate response. For all aggressive dogs, it is very important to determine the appropriateness of the behavior. Was the dog threatened, or was the aggressiveness really unprovoked

Effects of divergent selection for leg weakness on muscle and bone characteristics in Duroc swine

The dimensions and weights of front leg muscles, tendons, and bones were determined in 44 gilts that were offspring of three Duroc lines from a five-generation divergent-selection experiment on leg weakness. Lines were low, control, and high, with the low line having the greatest leg weakness and the high-line having the least leg weakness. At a slaughter weight of approximately 118 kg, the right front leg was removed from the carcasses of 14 low-, 16 control-, and 14 high-line gilts. Each intrinsic muscle was dissected from origin to insertion, removed from the leg, and measured for total length and weight. The skeleton of the front leg was disarticulated so that each bone was freed and thoroughly cleaned of muscle remnants and connective tissue. The shoulder and elbow joints were scored for the presence of osteochondral lesions. Each bone was weighed, and various dimensional traits were measured. The model used to analyze the data included the effects of line, sire within line, and weight as a covariate. The biceps brachii muscle weight and length were significantly greater in low-line pigs than in control- or high-line pigs (P \u3c 0.05). Collectively, the forearm extensor weights were significantly greater in low-line pigs than in control- or high-line pigs (P \u3c 0.05). The humeral and metacarpal bones were shorter in high-line pigs than in control- or low-line pigs (P \u3c 0.05). The head of the humerus was wider and the angle of the head of the humerus was greater in high-line pigs than in control- or low-line pigs (P \u3c 0.05). Divergent selection for differing degrees of leg soundness in Duroc swine appears to be associated with major differences in front-leg bone and muscle lengths and weights

Optimization of a Ribosomal Structural Domain by Natural Selection

A conserved, independently folding domain in the large ribosomal subunit consists of 58 nt of rRNA and a single protein, L11. The tertiary structure of an rRNA fragment carrying the Escherichia coli sequence is marginally stable in vitro but can be substantially stabilized by mutations found in other organisms. To distinguish between possible reasons why natural selection has not evolved a more stable rRNA structure in E. coli, mutations affecting the rRNA tertiary structure were assessed for their in vitro effects on rRNA stability and L11 affinity (in the context of an rRNA fragment) or in vivo effects on cell growth rate and L11 content of ribosomes. The rRNA fragment stabilities ranged from -4 to +9 kcal/mol relative to the wild-type sequence. Variants in the range of -4 to +5 kcal/mol had almost no observable effect in vivo, while more destabilizing mutations (\u3e7 kcal/mol) were not tolerated. The data suggest that the in vivo stability of the complex is roughly -6 kcal/mol and that any single tertiary interaction is dispensable for function as long as a minimum stability of the complex is maintained. On the basis of these data, it seems that the evolution of this domain has not been constrained by inherent structural or functional limits on stability. The estimated stability corresponds to only a few ribosomes per bacterial cell dissociated from L11 at any time; thus the selective advantage for any further increase in stability may be so small as to be outweighed by other competing selective pressures

Multiple hybridization events, polyploidy and low postmating isolation entangle the evolution of neotropical species of Epidendrum (Orchidaceae)

Background: Hybridization and polyploidy are central processes in evolution and speciation. These mechanisms often lead to complex patterns of genetic variation and the creation of novel genotypes, which may establish if they become isolated from gene flow. However, in the absence of reproductive isolation, species boundaries might easily be disrupted. Here, we used a combination of AFLPs, chloroplast DNA markers and flow cytometry to investigate the evolutionary outcomes of hybridization between two endemic Ecuadorian species of Epidendrum (E. madsenii and E. rhopalostele) in three hybrid zones. Postmating isolation was also quantified to determine the role of this barrier in restraining gene flow between hybrids and the parental species. In addition, future ecological niche models were constructed to predict the outcomes of hybridization between these species. Results: Our results confirmed the presence of hybrids in all hybrid zones, but revealed that a third parental species (E. falcisepalum) has contributed to one of the hybrid zones studied. Backcross genotypes were frequent in all hybrid zones, which was in accordance with the absence of strong reproductive barriers. The process of hybridization was highly asymmetric and followed in some cases by polyploidy. The projection of future niche models predicted a severe reduction in the area suitable for the occurrence of these species, although favorable conditions will still occur for the existence of the current hybrid zones. Conclusions: The recurrent process of hybridization has compromised the genetic integrity of the parental species. Most individuals of the parental species can no longer be considered as pure-bred individuals because most were classified as backcrossed hybrids. Novel genetic lineages occur in all hybrid zones implying that hybrids are fertile and can compete with the parental species. These results, together with the prediction of suitable conditions for the future occurrence of these hybrid zones, highlight the importance of conserving these geographic areas as sources of novel taxonomic entities

Optical and infrared photometry of the blazar PKS0537-441

We present a large collection of photometric data on the Blazar PKS 0537-441 in the VRIJHK bands taken in 2004-2009. At least three flare-like episodes with months duration, and >3 mag amplitude are apparent. The spectral energy distribution is consistent with a power law, and no indication of a thermal component is found. We searched for short time scale variability, and an interesting event was identified in the J band, with a duration of ~25 minutes.Comment: 10 pages, 3 figures, in press in ApJ

Using Rheo-Small-Angle Neutron Scattering to Understand How Functionalised Dipeptides Form Gels

We explore the use of rheo-small-angle neutron scattering as a method to collect structural information from neutron scattering simultaneously with rheology to understand how low-molecular-weight hydrogels form and behave under shear. We examine three different gelling hydrogel systems to assess what structures are formed and how these influence the rheology. Furthermore, we probe what is happening to the network during syneresis and why the gels do not recover after an applied strain. All this information is vital when considering gels for applications such as 3D-printing and injection