Carleman estimates and absence of embedded eigenvalues

Let L be a Schroedinger operator with potential W in L^{(n+1)/2}. We prove that there is no embedded eigenvalue. The main tool is an Lp Carleman type estimate, which builds on delicate dispersive estimates established in a previous paper. The arguments extend to variable coefficient operators with long range potentials and with gradient potentials.Comment: 26 page

The immature stages and biology of two Xenapates species in West Africa (Hymenoptera, Tenthredinidae)

The immature stages and host plants of Xenapates Kirby, 1882 were hitherto unknown. We describe the larvae, prepupae and pupae of X. braunsi (Konow, 1896) and X. gaullei (Konow, 1896), and record observations on aspects of their biology. The relationship of Xenapates to other taxa currently placed in the Allantinae and Blennocampinae of the Tenthredinidae remains unclear. Most larval characters of Xenapates resemble those described for West Palaearctic Allantini (Allantinae) and some Blennocampinae, but unique amongst exophytic larvae of Tenthredinoidea is the complete absence of cuticular appendages on the dorsum of the trunk in the two Xenapates species studied. The setose outer surface of the abdominal prolegs of Xenapates, and the presence of a mesal ridge only on the left mandible, are character states that have not so far been recorded in other genera currently placed in the Allantinae or Blennocampinae. Larval host plants of X. braunsi are Digitaria horizontalis, Pennisetum purpureum, Setaria barbata and Zea mays (all Poaceae). X. gaullei larvae feed on two Commelina species (Commelinaceae). Larvae of both species are easy bleeders

A para-differential renormalization technique for nonlinear dispersive equations

For \alpha \in (1,2) we prove that the initial-value problem \partial_t u+D^\alpha\partial_x u+\partial_x(u^2/2)=0 on \mathbb{R}_x\times\mathbb{R}_t; u(0)=\phi, is globally well-posed in the space of real-valued L^2-functions. We use a frequency dependent renormalization method to control the strong low-high frequency interactions.Comment: 42 pages, no figure

Scanning electron microscopy preparation of the cellular actin cortex: A quantitative comparison between critical point drying and hexamethyldisilazane drying

The cellular cortex is an approximately 200-nm-thick actin network that lies just beneath the cell membrane. It is responsible for the mechanical properties of cells, and as such, it is involved in many cellular processes, including cell migration and cellular interactions with the environment. To develop a clear view of this dense structure, high-resolution imaging is essential. As one such technique, electron microscopy, involves complex sample preparation procedures. The final drying of these samples has significant influence on potential artifacts, like cell shrinkage and the formation of artifactual holes in the actin cortex. In this study, we compared the three most used final sample drying procedures: critical-point drying (CPD), CPD with lens tissue (CPD-LT), and hexamethyldisilazane drying. We show that both hexamethyldisilazane and CPD-LT lead to fewer artifactual mesh holes within the actin cortex than CPD. Moreover, CPD-LT leads to significant reduction in cell height compared to hexamethyldisilazane and CPD. We conclude that the final drying procedure should be chosen according to the reduction in cell height, and so CPD-LT, or according to the spatial separation of the single layers of the actin cortex, and so hexamethyldisilazane

Screening for head and neck second primary tumors in patients with esophageal squamous cell cancer: A systematic review and meta-analysis

Background: Esophageal squamous cell carcinomas (ESCCs) are often accompanied by head and neck second primary tumors (HNSPTs). The prognosis of patients with an additional HNSPT is worse compared with patients with only ESCC. Therefore, early detection of HNSPTs may improve the overall outcome of patients with ESCC. The purpose of this study was to investigate the yield of endoscopic screening for HNSPTs in patients with primary ESCC. Methods: We conducted a systematic literature search of all available databases. Studies were included if ESCC patients were endoscopically screened for HNSPT. The primary outcome was the pooled prevalence of HNSPTs. Results: Twelve studies, all performed in Japan, were included in this systematic review with a total of 6483 patients. The pooled prevalence of HNSPTs was 6.7% (95% confidence interval: 4.9–8.4). The overall heterogeneity was high across the studies (I 2 ¼ 89.0%, p < 0.001). Most HNSPTs were low stage (85.3%) and located in the hypopharynx (60.3%). The proportion of synchronous (48.2%) and metachronous (51.8%) HNSPTs was comparable. Conclusion: Based on our results, HNSPT screening could be considered in patients with primary ESCC. All studies were performed in Japan; it is therefore not clear whether this consideration applies to the Western world

A novel universal algorithm for filament network tracing and cytoskeleton analysis

The rapid development of advanced microscopy techniques over recent decades has significantly increased the quality of imaging and our understanding of subcellular structures, such as the organization of the filaments of the cytoskeleton using fluorescence and electron microscopy. However, these recent improvements in imaging techniques have not been matched by similar development of techniques for computational analysis of the images of filament networks that can now be obtained. Hence, for a wide range of applications, reliable computational analysis of such two-dimensional methods remains challenging. Here, we present a new algorithm for tracing of filament networks. This software can extract many important parameters from grayscale images of filament networks, including the mesh hole size, and filament length and connectivity (also known as Coordination Number). In addition, the method allows sub-networks to be distinguished in two-dimensional images using intensity thresholding. We show that the algorithm can be used to analyze images of cytoskeleton networks obtained using different advanced microscopy methods. We have thus developed a new improved method for computational analysis of two-dimensional images of filamentous networks that has wide applications for existing imaging techniques. The algorithm is available as open-source software

Appraising the Effectiveness of a Simple Evaluational Approach to Problems of Retardation and Behavior in Childhood

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67035/2/10.1177_000992287201100921.pd

Face and construct validity of a novel mechanical ERCP simulator

__Background__ and study aims Simulation-based training has become an important pillar in competence-based medicine. However, limited data are available on use of simulators in training for endoscopic retrograde cholangiopancreatography (ERCP). We aimed to determine the face and construct validity of the Boškoski-Costamagna mechanical ERCP Trainer, and to assess its didactic value, as judged by experts. Methods Participants were divided into four groups based on ERCP lifetime experience: novices, intermediate, experienced, and experts. Participants performed several standardized assignments on the simulator. Outcome parameters included times to complete the procedure, ability to cannulate both ducts, number of attempts to cannulate the common bile duct and pancreatic duct, number of inadvertent pancreatic duct cannulations, successful stent placement, and successful stone extraction. All experts filled out a questionnaire on the simulator’s realism and didactic value. Results Novices (n = 11) completed the total procedure in 21:09 (min:sec), intermediates (n = 5) in 10:58, experienced (n = 8) in 06:42 and experts (n = 22) in 06:05. Experts were significantly faster than novices (Kruskal-Wallis test P < 0.000). Experts rated the realism of the simulator 7.12 on a 10-point Likert scale. The simulator’s potential as a tool for training novices was rated 3.91 on a four-point Likert scale, and there was a high agreement among experts to include the simulator in the training of novice endoscopists (3.86 on a four-point Likert scale). Conclusions The novel Boškoski-Costamagna ERCP simulator demonstrates good face and construct validity. ERCP experts highly agree on the didactic value and added value of this simulator in the training curriculum for novice endoscopists