Development, Survival and Phenology of the Sweetclover Weevil Parasitoid, \u3ci\u3ePygostolus Falcatus\u3c/i\u3e (Hymenoptera: Braconidae)

Biennial sweetclovers were widely used for soil improvement and as for- ages in the first half of the 1900s. The introduction of the sweetclover weevil, Sitona cylindricollis, caused a drastic decline in sweetclover acreage. In North Dakota, yellow sweetclover, Melilotus officinalis, is still the legume of choice on organic farms. In an effort to control the weevil, the thelyotokous parasitoid Pygostolus falcatus was imported. Parasitoids were studied for temperature-dependent development, and adult longevity as influenced by temperature and availability of provisions. Development from egg to adult at 15, 20, 25 and 30°C was 58, 28, 22 and 21 d, respectively. No parasitoids were reared out at 10°C, although diapausing first instars were present. Longevity of adult parasitoids provided honey, water, sweetclover and sweet- clover weevils at 15, 20, 25 and 30°C was 29, 22, 12 and 6 d, respectively. Adults provided the following combinations of provisions at 25°C survived for: nothing-2 d; water-2 d; honey-4 d; honey and water - 6 d; honey, water and sweetclover - 11 d; honey, water, sweetclover and hosts - 12 d. Field cage releases and a degree-day model developed for the parasitoid demonstrated that poor synchrony between P. falcatus and the sweetclover weevil hinders its usefulness as a biological control agent

Specific Adherence of Escherichia coli (Strain RDEC-1) to Membranous (M) Cells of the Peyer\u27s Patch in Escherichia coli Diarrhea in the Rabbit

The RDEC-1 strain Escherichia coli is an enteroadherent bacterium that produces diarrhea in the rabbit. A histopathologically similar disease has been described in humans. The RDEC-1 bacterium adheres to the epithelium of lymphoid follicles in rabbit ileal Peyer\u27s patches by 4 h postinoculation, 3-4 d before its adherence to absorptive epithelium. The purpose of this study was to determine whether the RDEC-1 bacterium adheres to a specific cell type in the lymphoid follicle epithelium. RDEC-1 bacteria were given in a dose of 2 X 10^6 by the orogastric route to postweanling rabbits. The distal ileal Peyer\u27s patch, taken from 5 control rabbits and 43 rabbits at intervals in the first 24 h postinoculation, was examined by routine and high-voltage electron microscopy. The RDEC-1 bacterium adhered specifically to M (membranous) rather than absorptive epithelial cells of the lymphoid follicle epithelium. Further understanding of how the bacterium attaches to M cells, which transport antigens to intraepithelial lymphocytes, could be useful in designing vaccines to protect mucosal surfaces

Development, Survival and Phenology of the Sweetclover Weevil Parasitoid, \u3ci\u3ePygostolus Falcatus\u3c/i\u3e (Hymenoptera: Braconidae)

Biennial sweetclovers were widely used for soil improvement and as for- ages in the first half of the 1900s. The introduction of the sweetclover weevil, Sitona cylindricollis, caused a drastic decline in sweetclover acreage. In North Dakota, yellow sweetclover, Melilotus officinalis, is still the legume of choice on organic farms. In an effort to control the weevil, the thelyotokous parasitoid Pygostolus falcatus was imported. Parasitoids were studied for temperature-dependent development, and adult longevity as influenced by temperature and availability of provisions. Development from egg to adult at 15, 20, 25 and 30°C was 58, 28, 22 and 21 d, respectively. No parasitoids were reared out at 10°C, although diapausing first instars were present. Longevity of adult parasitoids provided honey, water, sweetclover and sweet- clover weevils at 15, 20, 25 and 30°C was 29, 22, 12 and 6 d, respectively. Adults provided the following combinations of provisions at 25°C survived for: nothing-2 d; water-2 d; honey-4 d; honey and water - 6 d; honey, water and sweetclover - 11 d; honey, water, sweetclover and hosts - 12 d. Field cage releases and a degree-day model developed for the parasitoid demonstrated that poor synchrony between P. falcatus and the sweetclover weevil hinders its usefulness as a biological control agent

Let\u27s Talk Body: An Applied Senior Project on Social Media Body Image

This paper discusses the overwhelming presence of social media platforms like Instagram and TikTok in the recent generation\u27s (Gen-Z) daily lives. Influencers have become the new celebrities by creating a “relatable and desirable” lifestyle that users aspire to gain. However, the pressure to conform to unrealistic beauty standards and buy promoted products can lead to negative effects on users\u27 mental health and self-esteem. The authors of this paper (Tonges and Dwyer) have created a podcast and Instagram account to encourage an honest conversation about the impact of social media on one’s actions, emotions, and brain chemistry. By analyzing social media through communication theories such as Social Cognitive Theory, Users and Gratification Theory, and Cultivation Theory, the authors hope to shed light on the problems associated with the use of social media

Nested Gausslet Basis Sets

We introduce nested gausslet (NG) bases, an improvement on previous gausslet bases which can treat systems containing atoms with much larger atomic number. We also introduce pure Gaussian distorted gausslet bases, which allow the Hamiltonian integrals to be performed analytically, as well as hybrid bases in which the gausslets are combined with standard Gaussian-type bases. All these bases feature the diagonal approximation for the electron-electron interactions, so that the Hamiltonian is completely defined by two $N_b\times N_b$ matrices, where $N_b \approx 10^4$ is small enough to permit fast calculations at the Hartree-Fock level. In constructing these bases we have gained new mathematical insight into the construction of one-dimensional diagonal bases. In particular we have proved an important theorem relating four key basis set properties: completeness, orthogonality, zero-moment conditions, and diagonalization of the coordinate operator matrix. We test our basis sets on small systems with a focus on high accuracy, obtaining, for example, an accuracy of $2\times10^{-5}$ Ha for the total Hartree-Fock energy of the neon atom in the complete basis set limit.Comment: 14 pages, 12 figure

Peyer\u27s Patch Lymphoid Follicle Epithelial Adherence of a Rabbit Enteropathogenic Escherichia coli (Strain RDEC-1) Role of Plasmid-Mediated Pili in Initial Adherence

Escherichia coli (strain RDEC- 1) adheres to M cells of rabbit Peyer\u27s patch lymphoid follicle epithelium. The RDEC-1 strain contains an 85 X 10^6 D plasmid that codes for pili, which, when purified, adhere to gut absorptive epithelium. This study compared the in vivo lymphoid follicle adherence of the RDEC- 1 strain with that of a Shigella flexneri (ShD 15) that contained the 85 X 10^6 D plasmid and expressed the RDEC-l pili, a control E. coli, and a control S. flexneri (ShD 12). The bacteria were given in a dose of 10^10 to 0.7-1.1 kg rabbits. The rabbits were sacrificed at 2, 4, 6, and 12 h postinoculation. Peyer\u27s patch tissue was examined by electronmicroscopy and direct fluorescence microscopy. The piliated ShD 15 and RDEC-1 bacteria adhered in large numbers at 2 and 4 h postinoculation, but only the RDEC1 strain persisted and increased in numbers past that time. Control strains did not adhere. The ShD 15 strain adhered to and was rapidly taken into M cells, precipitating an acute inflammatory reaction within the follicle and adjacent lumen. Initial lymphoid follicle M cell adherence of the ShD 15 strain was associated with the possession of the adherence pilus plasmid. The failure of the ShD 15 strain to survive and colonize the lymph follicle epithelium contrasts with the success of the RDEC-1 strain and indicates that the RDEC-1 strain possesses virulence factors in addition to pili

Measurement of mutual inductance from frequency dependence of impedance of AC coupled circuit using digital dual-phase lock-in amplifier

We present a simple method to determine the mutual inductance $M$ between two coils in a coupled AC circuit by using a digital dual-phase lock-in amplifier. The frequency dependence of the real and imaginary parts is measured as the coupling constant is changed. The mutual inductance $M$ decreases as the distance $d$ between the centers of coils is increased. We show that the coupling constant is proportional to $d^{-n}$ with an exponent $n$ ($\approx$ 3). This coupling is similar to that of two magnetic moments coupled through a dipole-dipole interaction.Comment: 9 pages, 10 figures, Fig.1 is corrected, figures in png files, short version is published in Am. J. Phys. 76, (2008) 12

THE IMPLICATIONS OF A NORTH AMERICAN FREE TRADE AREA FOR AGRICULTURE

This is one of two papers commissioned by the International Agricultural Trade Research Consortium on various aspects related to the agricultural sector of a prospective North American Free Trade Agreement. The companion paper to this one has been prepared by a working group chaired by Thomas Grennes, North Carolina State University. To minimize duplication with the Grennes paper, this paper has given greater attention to the general trade policy issues raised by a NAFTA, institutional factors, additional commodity detail in cereals, fruit and vegetables, and the relevance of other regional trade agreements such as the Canada-U.S. Trade Agreement. This work has also benefitted from an earlier report and its annexes, prepared for the Fraser Institute, under the direction of Tim Josling.International Relations/Trade,