Rat control

During the past few years the rat population in Iowa has built up until it is now estimated that there are more than 5 million rats in the state. This rapid increase in population is due primarily to the tremendous volume of corn which is stored in temporary, hastily-constructed cribs that offer easy access to rats and furnish both food and shelter for them. To meet this situation, it is urged that rat control be made an integral part of good farm practice. Since rats move about from farm to farm, especially when they are disturbed by a vigorous control campaign on the part of a few farmers, community cooperation is desired. Rats menace not only our food and our farm animals; from the standpoint of health they threaten both humans and domestic animals, since they may act as reservoirs of infectious jaundice, endemic typhus and bubonic plague in man and trichinosis of hogs

Masonry barn design and construction

In 1913 an investigation was begun with the object of developing an all masonry barn which could be constructed at a reasonable cost and yet have the advantages of permanent and fire resistant construction. The studies which have been conducted pertain chiefly to the roof structure, with particular emphasis on the method of construction. In addition to a number of design studies, models of roof sections were built to develop a method of roof construction. Strength tests were made on roof models to check the reliability of the designs. The information obtained served as the basis of the design and method of constructing an experimental barn, which was built at Iowa State College in 1926-27. Common overall dimensions and a desirable roof shape were established to make the roof forms usable for a number of barns; wind load assumptions were adapted from reliable wind pressure investigations to permit a more intelligent and efficient roof design. The results of the design studies, construction and tests on models and roof sections, and the construction of the experimental barn, together with other related experiences, seem to warrant the following general conclusions: 1. The masonry arch is a very stable type of roof structure as shown by the tests on sections, which check closely the design calculations. 2. The construction of the roof is difficult and involves a large amount of labor because of: a. The use of heavy steel forms to carry a large part of the roof weight. b. The manipulation of the forms in erection, moving, dismantling and transporting. c. The handling and placing of roof materials. 3. The additional cost of the roof over a wood frame type construction is due. not so much to the cost of materials, as to the cost of the unproductive labor in handling the materials and in manipulation of the steel forms. The overhead cost of the forms becomes a large item in the first cost if they are used for only one or a few barns. 4. Experiments in the methods of making a roof watertight have not as yet indicated an entirely successful method. A heavy fibered asphalt has been found the best of the waterproof coatings which have been used. Leaks appear to be due to slight openings in the joints and to the development of fine cracks. 5. The construction of the roof should be directed by one . who is familiar with masonry construction. 6. A roof with a span of 34 ft. and a height of 20 ft. provides enough storage space for most conditions

What determines the length of life of prepared roll roofings?

The length of life of prepared roll roofings is a prime consideration in their selection. The durability of the various brands of roofing on the market varies widely. The useful life of a roof made of roll roofing is influenced by the degree of exposure to the weathering agencies, the condition of the sheathing and the inherent qualities of the roofing material itself. This bulletin is a summary of the results of an investigation, conducted cooperatively by the Agricultural and Engineering Experiment Stations, to determine the quality factors of three-ply prepared roll roofings as they were sold on the market at the beginning of the project in 1913. One roll or square of each of 35 brands of prepared roll roofing which were made by 19 manufacturers was purchased on the open market and included in the experiment. This provided sufficient material for one strip to be placed on the shed for weathering tests and enough additional for laboratory tests. Table I presents some general information and data of the physical qualities of the roofing sample. A review of literature on the subject reveals little work directly comparable with that given here other than the development of testing methods and specifications for prepared roll roofings

Wigner crystal versus Fermionization for one-dimensional Hubbard models with and without long-range interactions

The ground state properties of Hubbard model with or without long-range interactions in the regime with strongly repulsive on-site interaction are investigated by means of the exact diagonalization method. We show that the appearance of $N$-crests in the density profile of a trapped N-fermion system is a natural result of "fermionization" between antiparallel-spin fermions in the strongly repulsive limit and can not be taken as the only signature of Wigner crystal phase, as the static structure factor does not show any signature of crystallization. On the contrary, both the density distribution and static structure factor of Hubbard model with strong long-range interactions display clear signature of Wigner crystal. Our results indicate the important role of long-range interaction in the formation of Wigner crystal.Comment: 7 pages, 7 figure

Release properties of UCx_x and molten U targets

The release properties of UC$_x$ and molten U thick targets associated with a Nier- Bernas ion source have been studied. Two experimental methods are used to extract the release time. Results are presented and discussed for Kr, Cd, I and Xe

FtsK-Dependent Dimer Resolution on Multiple Chromosomes in the Pathogen Vibrio cholerae

Unlike most bacteria, Vibrio cholerae harbors two distinct, nonhomologous circular chromosomes (chromosome I and II). Many features of chromosome II are plasmid-like, which raised questions concerning its chromosomal nature. Plasmid replication and segregation are generally not coordinated with the bacterial cell cycle, further calling into question the mechanisms ensuring the synchronous management of chromosome I and II. Maintenance of circular replicons requires the resolution of dimers created by homologous recombination events. In Escherichia coli, chromosome dimers are resolved by the addition of a crossover at a specific site, dif, by two tyrosine recombinases, XerC and XerD. The process is coordinated with cell division through the activity of a DNA translocase, FtsK. Many E. coli plasmids also use XerCD for dimer resolution. However, the process is FtsK-independent. The two chromosomes of the V. cholerae N16961 strain carry divergent dimer resolution sites, dif1 and dif2. Here, we show that V. cholerae FtsK controls the addition of a crossover at dif1 and dif2 by a common pair of Xer recombinases. In addition, we show that specific DNA motifs dictate its orientation of translocation, the distribution of these motifs on chromosome I and chromosome II supporting the idea that FtsK translocation serves to bring together the resolution sites carried by a dimer at the time of cell division. Taken together, these results suggest that the same FtsK-dependent mechanism coordinates dimer resolution with cell division for each of the two V. cholerae chromosomes. Chromosome II dimer resolution thus stands as a bona fide chromosomal process

The role of RelA (p65) threonine 505 phosphorylation in the regulation of cell growth, survival, and migration

The NF-κB family of transcription factors is a well-established regulator of the immune and inflammatory responses and also plays a key role in other cellular processes, including cell death, proliferation, and migration. Conserved residues in the trans-activation domain of RelA, which can be posttranslationally modified, regulate divergent NF-κB functions in response to different cellular stimuli. Using rela(−/−) mouse embryonic fibroblasts reconstituted with RelA, we find that mutation of the threonine 505 (T505) phospho site to alanine has wide-ranging effects on NF-κB function. These include previously described effects on chemotherapeutic drug-induced apoptosis, as well as new roles for this modification in autophagy, cell proliferation, and migration. This last effect was associated with alterations in the actin cytoskeleton and expression of cellular migration–associated genes such as WAVE3 and α-actinin 4. We also define a new component of cisplatin-induced, RelA T505–dependent apoptosis, involving induction of NOXA gene expression, an effect explained at least in part through induction of the p53 homologue, p73. Therefore, in contrast to other RelA phosphorylation events, which positively regulate NF-κB function, we identified RelA T505 phosphorylation as a negative regulator of its ability to induce diverse cellular processes such as apoptosis, autophagy, proliferation, and migration

Reproductive Strategy of the Giant Electric Ray in the Southern Gulf of California

The objective of the present study was to describe and characterize macroscopic and microscopic aspects of the reproductive biology of the Giant Electric Ray Narcine entemedor, a viviparous elasmobranch targeted by commercial fishers in Mexico. A total of 305 individual rays were captured (260 females, 45 males); all males were sexually mature. The median size at maturity for females was estimated to be 58.5 cm TL, the median size at pregnancy was 63.7 cm TL, and the median size at maternity was 66.2 cm TL. The range of ovarian follicles recorded per female was 1–69; the maximum ovarian fecundity of fully grown vitellogenic oocytes was 17, and uterine fecundity ranged from 1 to 24 embryos per female. The lengths of the oblong ovarian follicles varied significantly among months, and the largest ovarian follicles were found in July, August, and September. Median embryo size was largest in August, and the size at birth was between 12.4 and 14.5 cm TL. Histological evidence of secretions from the glandular tissue of the uterine villi indicate that this species probably has limited histotrophy as a reproductive mode. Vitellogenesis in the ovary occurred synchronously with gestation in the uterus. The Giant Electric Ray has a continuous annual reproductive cycle; a period of ovulation occurs between May and September and two peaks of parturition, one in January and one in August, occur, suggesting that embryonic diapause occurs in some individuals. These results provide useful information for the management of this important commercial species in Bahía de La Paz, Mexico, and will allow possible modification of the current Mexican regulations to enable better protection of this species