The Biomedical Workforce in the US: An Example of Positive Feedbacks

This paper makes the case that the biomedical workforce in the United States is characterized by positive feedbacks. The paper begins by setting out background information on (1) the way in which research is structured in the biomedical sciences; (2) the reward structure among biomedical researchers; and (3) the funding enterprise for biomedical sciences. After addressing these three key components, the paper examines what these mean in terms of the market for graduate stud ents, postdocs and faculty. It then explores ways in which the positive-feedback mechanisms could be dampened. It concludes that the presence of positive feedbacks in the biomedical workforce is a result of system-wide problems. Any fix requires changing incentives. This is unlikely to occur as long as the U.S. Congress and faculty have their way.

A Substruction Approach to Assessing the Theoretical Validity of Measures

Background Validity is about the logic, meaningfulness, and evidence used to defend inferences made when interpreting results. Substruction is a heuristic or process that visually represent the hierarchical structure between theory and measures. Purpose To describe substruction as a method for assessing the toretical validity of research measures. Methods Using Fawcett\u27s Conceptual-Theoretical-Empirical Structure. an exemplar is presented of substruction from the Individual and Family Self-Management Theory to the Striving to be strong study concepts and empirical measures. Results Substruction tables display evidence supporting theoretical validity of the instruments used in the study. Conclusion A high degree of congruence between theory and measure is critical to support the validity of the theory and to support attributions made about moderating, mediating, causal relationships, and intervention effects

Spokes cluster: The search for the quiescent gas

Context. Understanding the role of fragmentation is one of the most important current questions of star formation. To better understand the process of star and cluster formation, we need to study in detail the physical structure and properties of the parental molecular cloud. The Spokes cluster, or NGC 2264 D, is a rich protostellar cluster where previous N2H+(1-0) observations of its dense cores presented linewidths consistent with supersonic turbulence. However, the fragmentation of the most massive of these cores appears to have a scale length consistent with that of the thermal Jeans length, suggesting that turbulence was not dominant. Aims. These two results probe different density regimes. Our aim is to determine if there is subsonic or less-turbulent gas (than previously reported) in the Spokes cluster at higher densities. Methods. We present APEX N2H+(3-2) and N2D+(3-2) observations of the NGC2264-D region to measure the linewidths and the deuteration fraction of the higher density gas. The critical densities of the selected transitions are more than an order of magnitude higher than that of N2H+(1-0). Results. We find that the N2H+(3-2) and N2D+(3-2) emission present significantly narrower linewidths than the emission from N2H+(1-0) for most cores. In two of the spectra, the nonthermal component is close (within 1-sigma) to the sound speed. In addition, we find that the three spatially segregated cores, for which no protostar had been confirmed show the highest levels of deuteration. Conclusions. These results show that the higher density gas, probed with N2H+ and N2D+(3-2), reveals more quiescent gas in the Spokes cluster than previously reported. More high-angular resolution interferometric observations using high-density tracers are needed to truly assess the kinematics and substructure within NGC2264-D. (Abridged)Comment: 8 pages, 4 figures. Accepted in A&

An Integrated Assessment of the Introduction of Lionfish (Pterois volitans/miles complex) to the Western Atlantic Ocean.

Lionfish (Pterois volitans/miles complex) are venomous coral reef fishes from the Indian and western Pacific oceans that are now found in the western Atlantic Ocean. Adult lionfish have been observed from Miami, Florida to Cape Hatteras, North Carolina, and juvenile lionfish have been observed off North Carolina, New York, and Bermuda. The large number of adults observed and the occurrence of juveniles indicate that lionfish are established and reproducing along the southeast United States coast. Introductions of marine species occur in many ways. Ballast water discharge, a very common method of introduction for marine invertebrates, is responsible for many freshwater fish introductions. In contrast, most marine fish introductions result from intentional stocking for fishery purposes. Lionfish, however, likely were introduced via unintentional or intentional aquarium releases, and the introduction of lionfish into United States waters should lead to an assessment of the threat posed by the aquarium trade as a vector for fish introductions. Currently, no management actions are being taken to limit the effect of lionfish on the southeast United States continental shelf ecosystem. Further, only limited funds have been made available for research. Nevertheless, the extent of the introduction has been documented and a forecast of the maximum potential spread of lionfish is being developed. Under a scenario of no management actions and limited research, three predictions are made: ● With no action, the lionfish population will continue to grow along the southeast United States shelf. ● Effects on the marine ecosystem of the southeast United States will become more noticeable as the lionfish population grows. ● There will be incidents of lionfish envenomations of divers and/or fishers along the east coast of the United States. Removing lionfish from the southeast United States continental shelf ecosystem would be expensive and likely impossible. A bounty could be established that would encourage the removal of fish and provide specimens for research. However, the bounty would need to be lower than the price of fish in the aquarium trade (~$25-$50 each) to ensure that captured specimens were from the wild. Such a low bounty may not provide enough incentive for capturing lionfish in the wild. Further, such action would only increase the interaction between the public and lionfish, increasing the risk of lionfish envenomations. As the introduction of lionfish is very likely irreversible, future actions should focus on five areas. 1) The population of lionfish should be tracked. 2) Research should be conducted so that scientists can make better predictions regarding the status of the invasion and the effects on native species, ecosystem function, and ecosystem services. 3) Outreach and education efforts must be increased, both specifically toward lionfish and more generally toward the aquarium trade as a method of fish introductions. 4) Additional regulation should be considered to reduce the frequency of marine fish introduction into U.S. waters. However, the issue is more complicated than simply limiting the import of non-native species, and these complexities need to be considered simultaneously. 5) Health care providers along the east coast of the United States need to be notified that a venomous fish is now resident along the southeast United States. The introduction and spread of lionfish illustrates the difficulty inherent in managing introduced species in marine systems. Introduced species often spread via natural mechanisms after the initial introduction. Efforts to control the introduction of marine fish will fail if managers do not consider the natural dispersal of a species following an introduction. Thus, management strategies limiting marine fish introductions need to be applied over the scale of natural ecological dispersal to be effective, pointing to the need for a regional management approach defined by natural processes not by political boundaries. The introduction and success of lionfish along the east coast should change the long-held perception that marine fish invasions are a minimal threat to marine ecosystems. Research is needed to determine the effects of specific invasive fish species in specific ecosystems. More broadly, a cohesive plan is needed to manage, mitigate and minimize the effects of marine invasive fish species on ecosystems that are already compromised by other human activities. Presently, the magnitude of marine fish introductions as a stressor on marine ecosystems cannot be quantified, but can no longer be dismissed as negligible. (PDF contains 31 pages

Exploring Thermal Processing of the Mildly Aqueously Altered Cm2 Eet 96029 Using Sulphide Mineralogy and Carbon Structure [abstract]

No abstract available

Neisseria gonorrhoeae challenge increases matrix metalloproteinase-8 expression in fallopian tube explants

Indexación: Scopus.Background: Neisseria gonorrhoeae (Ngo) is the etiological agent of gonorrhea, a sexually transmitted infection that initially infects the female lower genital tract. In untreated women, the bacteria can ascend to the upper genital reproductive tract and infect the fallopian tube (FTs), which is associated with salpingitis and can lead to impaired FT function and infertility. The extracellular matrix (ECM) plays an important role in cell migration and differentiation in the female genital tract, and some pathogens modify the ECM to establish successful infections. The ECM is regulated by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), their endogenous inhibitors; MMP deregulation causes pathological conditions in a variety of tissues. Results: The aim of this work was to analyze the expression and localization of MMP-3, MMP-8, MMP-9, and TIMP-1 in FT explants during Ngo infection using real-time PCR, immunohistochemistry, zymography and ELISA. No significant variations in MMP-3, MMP-9, and TIMP-1 transcript levels were observed. In contrast, a significant increase (p < 0.05) was observed for MMP-8 expression and was accompanied by stromal immunoreactivity in infected explants. ELISA results supported these findings and showed that MMP-8 release increased upon gonococcal infection. Conclusions: Our results indicate that gonococcal infection induces increased MMP-8 expression, which might contribute to FT damage during infection. © 2017 Juica, Rodas, Solar, Borda, Vargas, Muñoz, Paredes, Christodoulides and Velasquez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00399/ful