Discovery of the molecular hydrogen ion (h2(+)) in the planetary nebulae

Low-dispersion spectra of fifteen planetaries and hot subdwarfs were obtained with the short wavelength prime camera on IUE and continuous flux distributions corrected for interstellar extinction were derived. Several planetaries, particularly the young planetaries of high surface brightness, show anomalous flux distributions. The most anomalous case is NGC 6210. These anomalies may be explained as absorption by H2+ H2(+) in the nebula

Galaxy Morphology from NICMOS Parallel Imaging

We present high resolution NICMOS images of random fields obtained in parallel to other HST observations. We present galaxy number counts reaching H=24. The H-band galaxy counts show good agreement with the deepest I- and K-band counts obtained from ground-based data. We present the distribution of galaxies with morphological type to H<23. We find relatively fewer irregular galaxies compared to an I-band sample from the Hubble Deep Field, which we attribute to their blue color, rather than to morphological K-corrections. We conclude that the irregulars are intrinsically faint blue galaxies at z<1.Comment: 13 pages, including 4 figures. Accepted for publication in ApJ Letter

Endowment inequality in public goods games: A re-examination

We present a clean test of whether inequality in endowments affects contributions to a public good. It is a clean test because, to our knowledge, it is the first to control for possible endowment effects. We find that the key adverse effect of inequality arises because the rich reduce their contributions when there is inequality

A genetic assay for gene essentiality in Clostridium

Essential genes of pathogens are potential therapeutic targets, but are difficult to verify. Here, gene essentiality was determined by targeted knockout following engineered gene duplication. Null mutants of candidate essential genes of Clostridium difficile were viable only in the presence of a stable second copy of the gene

A Bibliometric Review on Risk Management and Building Information Modeling for International Construction

International construction is complicated and involves high risks. However, with the development of technological innovation, Building Information Modeling (BIM) emerged and seems to be able to address certain risks. To understand BIM applications in risk management for international construction, a state-of-the-art review is required. Therefore, this paper aims to identify the research trends and opportunities for risk management in BIM-enabled international construction by reviewing 526 peer-reviewed journal articles for the years 2007-2017. Thus five steps of bibliometric analysis were conducted based on the proposed frameworks of BIM risk management in international construction (BIM-RM-INTL). The results show that the popularization of BIM not only attracts all stakeholders' interests but also brings some risks. For example, financial factors are hard to detect and control through BIM, information loss during transmission stands out, and BIM has no unified standards and regulations for international construction. The research has mapped existing research results and their relationships for future risk management in BIM-enabled international construction

The Scholarship of Teaching MOOC-Based Degree Programs: Opportunities and Challenges

This paper explores the teaching component of scholarship in the Digital Age, with a focus on teaching online Massive Open Online Courses (MOOCs) aligned to degree programs. Instructors are increasingly embracing online teaching as part of their scholarly portfolio, including MOOC development and teaching. There is some empirical research on the impact of teaching stand-alone MOOCs on the instructors’ practices and on learners’ experiences. The impact of teaching MOOC-based degree programs on the instructors’ professional development has not been investigated to this date. This study explores the instructors’ experiences teaching program-aligned MOOCs, with a focus on the online MBA at the University of Illinois, which combines non-credit courses with traditional credit-bearing courses, and the impact teaching a MOOC-based degree has on their professional practice as digital scholars. Preliminary findings suggest that the experience of designing and delivering a MOOC informed the instructors' teaching practice, and they often reused MOOC content in their face-to face and blended classrooms. MOOC teaching may not replace traditional online teaching but is perceived as a complementary form of scholarship in teaching. Challenges noted are the time-consuming process of designing and developing the MOOC-based MBA course, and delivering instruction on two Learning Management Systems at the same time: Coursera for the non-credit MOOC component, and Blackboard for the credit-bearing portion of the online course. Further work will involve determining ways to design MOOCs that positively impact on the instructor’s teaching practices and instructor-learner interaction, with a view of increasing the performance and motivation of global learners and MOOC-based degree enrolled students.Ope

[Accepted Manuscript] In vitro susceptibility to closthioamide among clinical and reference strains of Neisseria gonorrhoeae.

Neisseria gonorrhoeae is one of the leading antimicrobial resistance threats worldwide. This study determined the minimum inhibitory concentrations of closthioamide to be 0.008-0.5 mg/L for clinical N. gonorrhoeae strains and related species. Cross-resistance with existing antimicrobial resistance was not detected, indicating that closthioamide could be used to treat drug-resistant N. gonorrhoeae

The permeability and elastic moduli of tuff from Campi Flegrei, Italy: implications for ground deformation modelling

The accuracy of ground deformation modelling at active volcanoes is a principal requirement in volcanic hazard mitigation. However, the reliability of such models relies on the accuracy of the rock physical property (permeability and elastic moduli) input parameters. Unfortunately, laboratory-derived values on representative rocks are usually rare. To this end we have performed a systematic laboratory study on the influence of pressure and temperature on the permeability and elastic moduli of samples from the two most widespread lithified pyroclastic deposits at the Campi Flegrei volcanic district, Italy. Our data show that the water permeability of Neapolitan Yellow Tuff and a tuff from the Campanian Ignimbrite differ by about 1.5 orders of magnitude. As pressure (depth) increases beyond the critical point for inelastic pore collapse (at an effective pressure of 10–15 MPa, or a depth of about 750 m), permeability and porosity decrease significantly, and ultrasonic wave velocities and dynamic elastic moduli increase significantly. Increasing the thermal stressing temperature increases the permeability and decreases the ultrasonic wave velocities and dynamic elastic moduli of the Neapolitan Yellow Tuff; whereas the tuff from the Campanian Ignimbrite remains unaffected. This difference is due to the presence of thermally unstable zeolites within the Neapolitan Yellow Tuff. For both rocks we also find, under the same pressure conditions, that the dynamic (calculated from ultrasonic wave velocities) and static (calculated from triaxial stress-strain data) elastic moduli differ significantly. The choice of elastic moduli in ground deformation modelling is therefore an important consideration. While we urge that these new laboratory data should be considered in routine ground deformation modelling, we highlight the challenges for ground deformation modelling based on the heterogeneous nature (vertically and laterally) of the rocks that comprise the caldera at Campi Flegrei

Spores of Clostridium engineered for clinical efficacy and safety cause regression and cure of tumors in vivo.

Spores of some species of the strictly anaerobic bacteria Clostridium naturally target and partially lyse the hypoxic cores of tumors, which tend to be refractory to conventional therapies. The anti-tumor effect can be augmented by engineering strains to convert a non-toxic prodrug into a cytotoxic drug specifically at the tumor site by expressing a prodrug-converting enzyme (PCE). Safe doses of the favored prodrug CB1954 lead to peak concentrations of 6.3 μM in patient sera, but at these concentration(s) known nitroreductase (NTR) PCEs for this prodrug show low activity. Furthermore, efficacious and safe Clostridium strains that stably express a PCE have not been reported. Here we identify a novel nitroreductase from Neisseria meningitidis, NmeNTR, which is able to activate CB1954 at clinically-achievable serum concentrations. An NmeNTR expression cassette, which does not contain an antibiotic resistance marker, was stably localized to the chromosome of Clostridium sporogenes using a new integration method, and the strain was disabled for safety and containment by making it a uracil auxotroph. The efficacy of Clostridium-Directed Enzyme Prodrug Therapy (CDEPT) using this system was demonstrated in a mouse xenograft model of human colon carcinoma. Substantial tumor suppression was achieved, and several animals were cured. These encouraging data suggest that the novel enzyme and strain engineering approach represent a promising platform for the clinical development of CDEPT

Gaps between zeros of Dedekind zeta-functions of quadratic number fields. II

Let $K$ be a quadratic number field and $\zeta_K(s)$ be the associated Dedekind zeta-function. We show that there are infinitely many normalized gaps between consecutive zeros of $\zeta_K(s)$ on the critical line which are greater than $2.866$ times the average spacing.Comment: 12 pages; to appear in the Quarterly Journal of Mathematic