A New Approximate Fracture Mechanics Analysis Methodology for Composites with a Crack or Hole

A new approximate theory which links the inherent flaw concept with the theory of crack tip stress singularities at a bi-material interface was developed. Three assumptions were made: (1) the existence of inherent flaw (i.e., damage zone) at the tip of the crack, (2) a fracture of the filamentary composites initiates at a crack lying in the matrix material at the interface of the matrix/filament, and (3) the laminate fails whenever the principal load-carrying laminae fails. This third assumption implies that for a laminate consisting of 0 degree plies, cracks into matrix perpendicular to the 0 degree filaments are the triggering mechanism for the final failure. Based on this theory, a parameter bar K sub Q which is similar to the stress intensity factor for isotropic materials but with a different dimension was defined. Utilizing existing test data, it was found that bar K sub Q can be treated as a material constant. Based on this finding a fracture mechanics analysis methodology was developed. The analytical results are correlated well with test results. This new approximate theory can apply to both brittle and metal matrix composite laminates with crack or hole

Chapter 4- Formal Mentoring Programs: Characteristics, Benefits, and Outcomes

In this chapter, we review the characteristics of mentoring that distinguish so-called formal from informal mentoring opportunities. Through this discussion, we provide a broad view of what could be formalized and how to distinguish these opportunities. We then turn to a discussion of the observed and anticipated benefits of formalized mentoring (and some benefits of mentoring broadly) and provide an argument for why mentoring, with all its recognized importance and impact at multiple levels, should not be left to chance. By formalizing mentoring opportunities and practices, to varying and customizable degrees, programs and institutions stand to distribute the benefits of such relationships more equitably and more effectively among their members and guard against the recognized risks of mentorship gone wrong. The benefits are clear to both mentees and mentors within formalized mentoring frameworks

Catastro de Fulgoroidea asociados a palmas en Puerto Rico

We report results from a survey of palm-associated Fulgoroidea (planthoppers), following the recent discoveries of Haplaxius crudus, a known palm phytoplasma vector, and of other potential planthopper vectors in Puerto Rico. The survey, which sampled from 40 sites, resulted In the identification of 30 morpho-species belonging to eight Fulgoroidea families. The 10 most common species accounted for 93.9% of individuals, whereas near one third (n = 9) of the species were represented by single individuals. Derbids and cixiids accounted for 90% of collected individuals. The most common species were the derbids Cedusa inflata (Ball) and Omolicna puertana Caldwell, while the most common cixiids were Bothriocera undata (F.) and Oliarus complectus Ball; and the most common flatids were Petrusa epilepsis (Kirkaldy) and Melornemis antillarum (Kirkaldy). Three species are new records for Puerto Rico: the cixiids Haplaxius crudus Van Duzee and Nymphomyndus caribbaea (Fennah), and the derbid Neocenchrea ca. pallida Metcalf. Impact of polyphagy and of abundance-diversity patterns of this planthopper guild on phytoplasma epidemiology are briefly discussed.Luego de la reciente introducción en Puerto Rico del insecto vector del amarillamiento letal del cocotero, Haplaxius crudus, y de la identificación de un fitoplasma en palmas enfermas realizamos un catastro de potenciales vectores de la enfermedad en Puerto Rico. El catastro, que incluyó 40 localidades y cubrió toda la isla, resultó en la identificación de 30 morfoespecies de Fulgoroidea, pertenecientes a ocho familias. Entre los hallazgos se encuentra que el 93.9% de los individuos coleccionados pertenecen a una de las 10 especies más comunes, y que cerca de un tercio de las especies fueron coleccionadas tan solo una vez. El 90% de los individuos pertenecían a las familias Derbidae y Cixiidae. Las especies más comunes fueron los dérbidos Cedusa inflata (Ball) y Omolicna puertana Caldwell, seguidos por los cixiidos Bothriocera undata (F.) y Oliarus complectus Ball; los flátidos más comunes fueron Petrusa epilepsis (Kirkaldy) y Melornemis antillarum (Kirkaldy). Tres especies constituyen nuevos récords para Puerto Rico: los cixiidos Haplaxius crudus Van Duzee y Nymphomyndus caribbaea (Fennah), y el dérbido Neocenchrea ca. pallida Metcalf. Se discuten las posibles implicaciones de la polifagia, y de los patrones de abundancia y diversidad sobre la epidemiología de los fitoplasmas de palmas

Propagación in vitro del platanero y el bananero en Puerto Rico

Some 7,000 plantlets were produced in vitro from six plantain cultivars (Enano Común, Congo Enano, Maricongo, Congo, Clone 12 and Clone 7), and from three banana cultivars (Grand Nain, Valerie and Ziv) by supplementing Murashige and Skoog (MS) basal medium with 0.5 mg/L kinetin and 0.5 mg/L 6-benzylamino purine. Calli were induced by supplementing the MS basal medium with 0.05 mg/L 2,4-D, 0.1 mg/L NAA, 0.5 mg/L BA, 15% coconut water and 20 mg/L ascorbic acid (filter sterilized). Data obtained from a replicated field trial at the Corozal Substation with the above-mentioned plantain cultivars indicated that the bunch weight from plantain cultivar Congo Enano, regenerated from axillary meristem with in vitro culture, was significantly greater than that from plantains derived from conventional suckers in the plant crop (P = 0.1). Similarly, the individual fruit weight from Congo Enano derived from meristem culture was significantly greater than that from plantains derived from the conventional planting materials (P = 0.5).Alrededor de 7,000 plántulas de plátano de 6 cultivares (Enano común, Congo enano, Maricongo, Congo, Clon 12 y Clon 7) se obtuvieron por cultivo de tejidos, suplementando el medio basal de Murashige y Skoog (MS) con cinetina (KIN) 0.5 mg./l. y benzilaminopurina (BA) 0.5 mg./l. Se obtuvo la inducción de callo suplementando el medio basal de MS con ácido 2,4-diclorofenoxiacético (2,4-D) 0.05 mg./l. , ácido naftalenoacético (NAA) 0.1 mg./l. benzilaminopurina (BA) 0.5 mg./l., agua de coco 15% (v/v) ácido ascórbico (filtrado por esterilización) 20 mg./l. Los datos obtenidos del experimento de campo realizado en la Subestación de Corozal, con las variedades de plátano arriba mencionadas, indicaron que el peso del racimo de la cultivar Congo enano propagado por cultivo de tejidos fue significativamente (P = 0.1) mayor que el del racimo propagado por el método corriente. Similarmente, el peso de las frutas individuales del Congo enano provenientes de plátanos propagados por tejido meristemático fue significativamente mayor ( P = 0.5) que el de los que provenían del método corriente

GNSS Spoof Detection Using Shipboard IMU Measurements

A variety of approaches have been proposed in the literature to detect spooing of Global Navigation Satellite Systems (GNSS). These approaches vary widely based upon the assumed capabilities and a priori knowledge of the spoofer. This paper considers a method to detect spoofing based on comparing the relative (not absolute) platform trajectory estimated by the GNSS receiver to the relative trajectory developed from IMU measurements (specifically pitch and roll from a gyro compass). The primary contribution of this paper is the development and analysis of a GNSS spoofing detection algorithm that exploits the unknown (to the spoofer) “high” frequency pitch/roll motion of the ship as seen by a commercial-off-the-shelf (COTS) receiver and an inertial measurement unit (IMU) that may already be in use onboard ships. We focus on generalized likelihood ratio tests using simple models of the GNSS and gyro measurements. Further, we avoid using a navigation filter, such as the extended Kalman filter, on the measurements; instead, the algorithm directly employs the instantaneous trajectories. Experimental results are shown using a commercial GNSS receiver with data from a GNSS simulator with IMU capability. The length of time and amount of motion required to achieve low probabilities of false alarm and missed detection are analyzed

Making Connections: A Handbook for Effective Formal Mentoring Programs in Academia

This book, Making Connections: A Handbook for Effective Formal Mentoring Programs in Academia, makes a unique and needed contribution to the mentoring field as it focuses solely on mentoring in academia. This handbook is a collaborative institutional effort between Utah State University’s (USU) Empowering Teaching Open Access Book Series and the Mentoring Institute at the University of New Mexico (UNM). This book is available through (a) an e-book through Pressbooks, (b) a downloadable PDF version on USU’s Open Access Book Series website), and (c) a print version available for purchase on the USU Empower Teaching Open Access page, and on Amazon

Emergence of Anthrax Edema Toxin as a Master Manipulator of Macrophage and B Cell Functions

Anthrax edema toxin (ET), a powerful adenylyl cyclase, is an important virulence factor of Bacillus anthracis. Until recently, only a modest amount of research was performed to understand the role this toxin plays in the organism’s immune evasion strategy. A new wave of studies have begun to elucidate the effects this toxin has on a variety of host cells. While efforts have been made to illuminate the effect ET has on cells of the adaptive immune system, such as T cells, the greatest focus has been on cells of the innate immune system, particularly the macrophage. Here we discuss the immunoevasive activities that ET exerts on macrophages, as well as new research on the effects of this toxin on B cells

Quality of life among Latina breast cancer patients: a systematic review of the literature

Introduction The Latino population is the most rapidly growing ethnic minority in the United States and Latinas have higher rates of advanced breast cancer and more rigorous treatments than White women. However, the literature lacks reviews on quality of life among this population of breast cancer patients. Methods A systematic review of the breast cancer quality of life (QOL) literature was conducted among studies that provided a comparison of mental, physical, social, or sexual QOL between Latinas and other racial/ethnic groups. Of the 375 studies reviewed, 20 quantitative studies and two qualitative studies met criteria for inclusion. Results Latinas were more likely to report poor mental, physical, and social QOL, relative to non-Latinas. Only four studies assessed sexual QOL, making it difficult to draw any conclusions. Of these four QOL domains, the largest disparity was found in the area of mental health in which Latinas reported poorer QOL compared to non-Latina Whites and Blacks. Discussion/conclusions Most quantitative studies revealed either that Latinas consistently evidenced significantly lower QOL than non-Latinas on all measures (6 studies) or reported mixed findings in which Latinas generally demonstrated significantly worse QOL on most, but not all, measures (12 studies) included in the study. Explanatory mechanisms including socio-demographic, treatment-related, and culturally-relevant factors are discussed. Implications for research design, measurement, and clinical work are also included. Implications for cancer survivors Although not entirely consistent, data suggest that Latina breast cancer survivors on average experience worse QOL than non-Latina Whites. Understanding ethnic differences in QOL among breast cancer survivors can inform interventions targeted at improving health status for Latinas

Radiotherapy Suppresses Angiogenesis in Mice through TGF-βRI/ALK5-Dependent Inhibition of Endothelial Cell Sprouting

BACKGROUND: Radiotherapy is widely used to treat cancer. While rapidly dividing cancer cells are naturally considered the main target of radiotherapy, emerging evidence indicates that radiotherapy also affects endothelial cell functions, and possibly also their angiogenic capacity. In spite of its clinical relevance, such putative anti-angiogenic effect of radiotherapy has not been thoroughly characterized. We have investigated the effect of ionizing radiation on angiogenesis using in vivo, ex vivo and in vitro experimental models in combination with genetic and pharmacological interventions. PRINCIPAL FINDINGS: Here we show that high doses ionizing radiation locally suppressed VEGF- and FGF-2-induced Matrigel plug angiogenesis in mice in vivo and prevented endothelial cell sprouting from mouse aortic rings following in vivo or ex vivo irradiation. Quiescent human endothelial cells exposed to ionizing radiation in vitro resisted apoptosis, demonstrated reduced sprouting, migration and proliferation capacities, showed enhanced adhesion to matrix proteins, and underwent premature senescence. Irradiation induced the expression of P53 and P21 proteins in endothelial cells, but p53 or p21 deficiency and P21 silencing did not prevent radiation-induced inhibition of sprouting or proliferation. Radiation induced Smad-2 phosphorylation in skin in vivo and in endothelial cells in vitro. Inhibition of the TGF-beta type I receptor ALK5 rescued deficient endothelial cell sprouting and migration but not proliferation in vitro and restored defective Matrigel plug angiogenesis in irradiated mice in vivo. ALK5 inhibition, however, did not rescue deficient proliferation. Notch signaling, known to hinder angiogenesis, was activated by radiation but its inhibition, alone or in combination with ALK5 inhibition, did not rescue suppressed proliferation. CONCLUSIONS: These results demonstrate that irradiation of quiescent endothelial cells suppresses subsequent angiogenesis and that ALK5 is a critical mediator of this suppression. These results extend our understanding of radiotherapy-induced endothelial dysfunctions, relevant to both therapeutic and unwanted effects of radiotherapy

Anthrax Edema Toxin Modulates PKA- and CREB-Dependent Signaling in Two Phases

Background: Anthrax edema toxin (EdTx) is an adenylate cyclase which operates in the perinuclear region of host cells. However, the action of EdTx is poorly understood, especially at molecular level. The ability of EdTx to modulate cAMPdependent signaling was studied in Jurkat T cells and was compared with that of other cAMP-rising agents: Bordetella pertussis adenylate cyclase toxin, cholera toxin and forskolin. Methodology/Principal Findings: EdTx caused a prolonged increase of the intracellular cAMP concentration. This led to nuclear translocation of the cAMP-dependent protein kinase (PKA) catalytic subunit, phosphorylation of cAMP response element binding protein (CREB) and expression of a reporter gene under control of the cAMP response element. Neither p90 ribosomal S6 kinase nor mitogen- and stress-activated kinase, which mediate CREB phosphorylation during T cell activation, were involved. The duration of phospho-CREB binding to chromatin correlated with the spatio-temporal rise of cAMP levels. Strikingly, EdTx pre-treated T cells were unresponsive to other stimuli involving CREB phosphorylation such as addition of forskolin or T cell receptor cross-linking. Conclusions/Significance: We concluded that, in a first intoxication phase, EdTx induces PKA-dependent signaling, which culminates in CREB phosphorylation and activation of gene transcription. Subsequently CREB phosphorylation is impaired and therefore T cells are not able to respond to cues involving CREB. The present data functionally link the perinuclea