A survey of business education in the public high schools of New England

Thesis (Ed.M.)--Boston University

Exact and explicit probability densities for one-sided Levy stable distributions

We study functions g_{\alpha}(x) which are one-sided, heavy-tailed Levy stable probability distributions of index \alpha, 0< \alpha <1, of fundamental importance in random systems, for anomalous diffusion and fractional kinetics. We furnish exact and explicit expression for g_{\alpha}(x), 0 \leq x < \infty, satisfying \int_{0}^{\infty} exp(-p x) g_{\alpha}(x) dx = exp(-p^{\alpha}), p>0, for all \alpha = l/k < 1, with k and l positive integers. We reproduce all the known results given by k\leq 4 and present many new exact solutions for k > 4, all expressed in terms of known functions. This will allow a 'fine-tuning' of \alpha in order to adapt g_{\alpha}(x) to a given experimental situation.Comment: 4 pages, 3 figures and 1 tabl

The subperichondrial / subperiosteal dissection in preservation rhinoplasty: how histology can help us to perform better surgeries

Aim: The classical dissection plane in rhinoplasty is in the sub-SMAS plane with traumatic dissection of tissues and as a result significant and prolonged postoperative edema, especially in the external approach. A complete subperichondrial/periosteal route has been recently described. It seems to allow for simpler postoperative follow-up than external or closed approach performed in the sub-SMAS plane. However, little is known about the exact histological planes that are really dissected during surgery. Material and methods: Histological examinations of 10 cadavers noses dissected in the so-called subperichondrial/subperiosteal plane were performed. Results: The subperichondrial plane is truly subperichondrial and consists in a dissection under the chondrogenic layer of the perichondrium. Subperichondrial dissection necessitates sharp scrapping to separate the cartilage from the chondrogenic layer. The perichondrium is naturally thicker on the dorsum, which explains why it is easier to begin the dorsal dissection at the W point. Scroll cartilages are consistent and show between 9 and 13 isolated cartilages, most of the time, 1 major and several minors cartilages. Optimal strategy to ease the dissection is discussed Conclusions: The subperichondrial/subperiosteal route, although necessitating significant dissection of the teguments of the nasal pyramid, is respectful of the anatomy of the nasal pyramid. It allows minimal traumatic maneuvers than in the sub-SMAS route, despite of the large dissection performed

The subperichondrial / subperiosteal dissection in preservation rhinoplasty: how histology can help us to perform better surgeries

Aim: The classical dissection plane in rhinoplasty is in the sub-SMAS plane with traumatic dissection of tissues and as a result significant and prolonged postoperative edema, especially in the external approach. A complete subperichondrial/periosteal route has been recently described. It seems to allow for simpler postoperative follow-up than external or closed approach performed in the sub-SMAS plane. However, little is known about the exact histological planes that are really dissected during surgery. Material and methods: Histological examinations of 10 cadavers noses dissected in the so-called subperichondrial/subperiosteal plane were performed. Results: The subperichondrial plane is truly subperichondrial and consists in a dissection under the chondrogenic layer of the perichondrium. Subperichondrial dissection necessitates sharp scrapping to separate the cartilage from the chondrogenic layer. The perichondrium is naturally thicker on the dorsum, which explains why it is easier to begin the dorsal dissection at the W point. Scroll cartilages are consistent and show between 9 and 13 isolated cartilages, most of the time, 1 major and several minors cartilages. Optimal strategy to ease the dissection is discussed Conclusions: The subperichondrial/subperiosteal route, although necessitating significant dissection of the teguments of the nasal pyramid, is respectful of the anatomy of the nasal pyramid. It allows minimal traumatic maneuvers than in the sub-SMAS route, despite of the large dissection performed

Interference between magnetic field and cavity modes in an extended Josephson junction

An extended Josephson junction consists of two superconducting electrodes that are separated by an insulator and it is therefore also a microwave cavity. The superconducting phase difference across the junction determines the supercurrent as well as its spatial distribution. Both, an external magnetic field and a resonant cavity intrafield produce a spatial modification of the superconducting phase along the junction. The interplay between these two effects leads to interference in the critical current of the junction and allows us to continuously tune the coupling strength between the first cavity mode and the Josephson phase from 1 to -0.5. This enables static and dynamic control over the junction in the ultra-strong coupling regime.Comment: 4 pages, 3 figure

The anterior cribriform plate foramina: from anatomy to surgery

Background: Despite the development of anterior skull base surgery, the anatomy of the nasal bone and anterior cribriform plate remains unclear. A recent study confirmed 2 distinct foramina in the anterior part of the cribriform plate: the ethmoidal slit (ES) and the cribroethmoidal foramen (CF). The aim of this study was to specify their content, their anatomic relationship to the frontal sinus and skull base, and their potential value in skull base surgery. Methods: Dissections were performed on 36 cadaver heads. Macro- and microscopic examinations were carried out. Microcomputed tomography scans contrasted with osmium were performed to identify vessels and nerves. Histology with neural, meningeal, or luteinizing hormone-releasing hormone immunomarkers was performed on the content of the foramina. Finally, endonasal surgical dissections were carried out. Results: The ES and the CF were observed in all cases. They measured a mean of 4.2 and 1.6 mm, respectively. The ES contained dura mater, arachnoid tissues, lymphatics, and the terminal nerve. The CF contained the anterior ethmoidal nerve and artery. This foramen continued forward with the cribroethmoidal groove, which measured a mean of 2.5 mm. This groove was under the frontal sinus and in front of the skull base. We also described a "cribroethmoidal canal" and a "nasal bone foramen." Clinical applications are discussed. Conclusion: The clinical applications of this new anatomic description concern both the cribriform plate and frontal sinus surgeries. Identifying the terminal nerve passing through the ES is a step forward in understanding pheromone recognition in humans

The anterior cribriform plate foramina: from anatomy to surgery

Background: Despite the development of anterior skull base surgery, the anatomy of the nasal bone and anterior cribriform plate remains unclear. A recent study confirmed 2 distinct foramina in the anterior part of the cribriform plate: the ethmoidal slit (ES) and the cribroethmoidal foramen (CF). The aim of this study was to specify their content, their anatomic relationship to the frontal sinus and skull base, and their potential value in skull base surgery. Methods: Dissections were performed on 36 cadaver heads. Macro- and microscopic examinations were carried out. Microcomputed tomography scans contrasted with osmium were performed to identify vessels and nerves. Histology with neural, meningeal, or luteinizing hormone-releasing hormone immunomarkers was performed on the content of the foramina. Finally, endonasal surgical dissections were carried out. Results: The ES and the CF were observed in all cases. They measured a mean of 4.2 and 1.6 mm, respectively. The ES contained dura mater, arachnoid tissues, lymphatics, and the terminal nerve. The CF contained the anterior ethmoidal nerve and artery. This foramen continued forward with the cribroethmoidal groove, which measured a mean of 2.5 mm. This groove was under the frontal sinus and in front of the skull base. We also described a "cribroethmoidal canal" and a "nasal bone foramen." Clinical applications are discussed. Conclusion: The clinical applications of this new anatomic description concern both the cribriform plate and frontal sinus surgeries. Identifying the terminal nerve passing through the ES is a step forward in understanding pheromone recognition in humans

Salmonella genomic island 1 (SGI1) reshapes the mating apparatus of IncC conjugative plasmids to promote self-propagation.

IncC conjugative plasmids and Salmonella genomic island 1 (SGI1) and relatives are frequently associated with multidrug resistance of clinical isolates of pathogenic Enterobacteriaceae. SGI1 is specifically mobilized in trans by IncA and IncC plasmids (commonly referred to as A/C plasmids) following its excision from the chromosome, an event triggered by the transcriptional activator complex AcaCD encoded by these helper plasmids. Although SGI1 is not self-transmissible, it carries three genes, traNS, traHS and traGS, coding for distant homologs of the predicted mating pore subunits TraNC, TraHC and TraGC, respectively, encoded by A/C plasmids. Here we investigated the regulation of traNS and traHGS and the role of these three genes in the transmissibility of SGI1. Transcriptional fusion of the promoter sequences of traNS and traHGS to the reporter gene lacZ confirmed that expression of these genes is inducible by AcaCD. Mating experiments using combinations of deletion mutants of SGI1 and the helper IncC plasmid pVCR94 revealed complex interactions between these two mobile genetic elements. Whereas traNC and traHGC are essential for IncC plasmid transfer, SGI1 could rescue null mutants of each individual gene revealing that TraNS, TraHS and TraGS are functional proteins. Complementation assays of individual traC and traS mutants showed that not only do TraNS/HS/GS replace TraNC/HC/GC in the mating pore encoded by IncC plasmids but also that traGS and traHS are both required for SGI1 optimal transfer. In fact, remodeling of the IncC-encoded mating pore by SGI1 was found to be essential to enhance transfer rate of SGI1 over the helper plasmid. Furthermore, traGS was found to be crucial to allow DNA transfer between cells bearing IncC helper plasmids, thereby suggesting that by remodeling the mating pore SGI1 disables an IncC-encoded entry exclusion mechanism. Hence traS genes facilitate the invasion by SGI1 of cell populations bearing IncC plasmids

A confined–unconfined aquifer model for subglacial hydrology and its application to the Northeast Greenland Ice Stream

Subglacial hydrology plays an important role in ice sheet dynamics as it determines the sliding velocity. It also drives freshwater into the ocean, leading to undercutting of calving fronts by plumes. Modeling subglacial water has been a challenge for decades. Only recently have new approaches been developed such as representing subglacial channels and thin water sheets by separate layers of variable hydraulic conductivity. We extend this concept by modeling a confined–unconfined aquifer system (CUAS) in a single layer of an equivalent porous medium (EPM). The advantage of this formulation is that it prevents unphysical values of pressure at reasonable computational cost. We performed sensitivity tests to investigate the effect of different model parameters. The strongest influence of model parameters was detected in terms of governing the opening and closure of the system. Furthermore, we applied the model to the Northeast Greenland Ice Stream, where an efficient system independent of seasonal input was identified about 500&thinsp;km downstream from the ice divide. Using the effective pressure from the hydrology model, the Ice Sheet System Model (ISSM) showed considerable improvements in modeled velocities in the coastal region.</p