Friedrich August Quenstedt (1809–1889) und die Evolutionstheorie

F. A. Quenstedt (University of Tübingen 1837–1889), master of Jurassic stratigraphy, was contrary to some misunderstandings also a forerunner of the gradualistic evolutionary idea.     

Obituary - Helmut Metzner (1925–1999)

Photosynthesis Research -     

The belemnites described by Baron Ernst Friedrich von Schlotheim (1764–1832)

E. F. v. Schlotheim described 46 species of Jurassic and Cretaceous belemnites in 1813,1820, and 1832. Their type specimens are in part housed at the Humboldt University of Berlin. The holotype ofBelemnites irregularis is here refigured. Lectotypes forB. acuarius, B. canaliculatus, B. clavatus, B. giganteus, andB. tripartitus are designated and figured for the first time. The lectotype ofBelemnites giganteus is designated to be the neotype ofBelemnites suevicus Klein 1773. 36 species are nomina nuda and nomina dubia, because none of their type specimens could be detected, among them the invalidB. paxillosus v. Schlotheim 1820, which is, according to its lectotype designated herein, likeBelemnites giganteus, a junior synonym ofMegateuthis suevica (Klein 1773). An original type specimenof Belemnites mucronatusv. Schlotheim 1813, for which a neotype had already been ruled by the ICZN in 1985, was re-discovered in thev. Schlotheim collection in 1996.v. Schlotheim’s belemnites were up to now designated to be type species of 12 genera.     

Celebrating 90 years of Peking University School of Life Sciences(1925–2015)

<正>The Department of Biology at Peking University was established in 1925,with Mr.Tan Xi Hong as its inaugural department head.In 1993,the department was renamed the School of Life Sciences.During the past 90 years,a steady stream of students has enrolled in the department in order to explore the secrets of life and to dedicate themselves to the advancement of society.     

Dr. Friedrich Steinbacher zum Ged?chtnis

Ohne Zusammenfassung     

Paul Henry Latimer (1925–2011): discoverer of selective scattering in photosynthetic systems

The response of marine phytoplankton to the ongoing increase in atmospheric pCO₂ reflects the consequences of both increased CO₂ concentration and decreased pH in surface seawater. In the model diatom Thalassiosira weissflogii, we explored the effects of varying pCO₂ and pH, independently and in concert, on photosynthesis and respiration by incubating samples in water enriched in H₂ ¹⁸O. In long-term experiments (~6-h) at saturating light intensity, we observed no effects of pH or pCO₂ on growth rate, photosynthesis or respiration. This absence of a measurable response reflects the very small change in energy used by the carbon concentrating mechanism (CCM) compared to the energy used in carbon fixation. In short-term experiments (~3 min), we also observed no effects of pCO₂ or pH, even under limiting light intensity. We surmise that in T. weissflogii, it is the photosynthetic production of NADPH and ATP, rather than the CO₂-saturation of Rubisco that controls the rate of photosynthesis at low irradiance. In short-term experiments, we observed a slightly higher respiration rate at low pH at the onset of the dark period, possibly reflecting the energy used for exporting H⁺ and maintaining pH homeostasis. Based on what is known of the biochemistry of marine phytoplankton, our results are likely generalizable to other diatoms and a number of other eukaryotic species. The direct effects of ocean acidification on growth, photosynthesis and respiration in these organisms should be small over the range of atmospheric pCO₂ predicted for the twenty-first century.     

Building on Bedrock: William Steel Creighton and the Reformation of Ant Systematics, 1925–1970

Ideas about the natural world are intertwined with the personalities, practices, and the workplaces of scientists. The relationships between these categories are explored in the life of the taxonomist William Steel Creighton. Creighton studied taxonomy under William Morton Wheeler at Harvard University. He took the rules he learned from Wheeler out of the museum and into the field. In testing the rules against a new situation, Creighton found them wanting. He sought a new set of taxonomic principles, one he eventually found in Ernst Mayr's Systematics and the Origin of Species. Mayr's ideas tied together a number of themes running through Creighton's life: the need for a revised taxonomy, the emphasis on fieldwork, and the search for a new power center for ant taxonomy after Wheeler died. Creighton's adoption of Mayr's ideas as part of his professional identity also had very real implications for his career path: field studies required long and intensive studies, and Creighton would always be a slow worker. His method of taxonomy contrasted sharply not only with Wheeler's but also with two of his younger colleagues, William L. Brown and E. O. Wilson, who took over Wheeler's spot at Harvard in 1950. The disputes between these men over ant taxonomy involved, in addition to questions of technical interest, questions about where and how best to do taxonomy and who could speak withthe most authority. Creighton's story reveals how these questions are interrelated. The story also reveals the importance of Mayr's book for changes occurring in taxonomy in the middle of the twentieth century. This revised version was published online in July 2006 with corrections to the Cover Date.     

Estimated HIV Incidence in California, 2006–2009

Introduction

Accurate estimates of HIV incidence are crucial for prioritizing, targeting, and evaluating HIV prevention efforts. Using the methodology the CDC used to estimate national HIV incidence, we estimated HIV incidence in Los Angeles County (LAC), San Francisco (SF), and California’s remaining counties.

Methods

We estimated new HIV infections in 2006–2009 among adults and adolescents in LAC, SF and the remaining California counties using the Serologic Testing Algorithm for Recent Seroconversion (STARHS). STARHS methodology uses the BED HIV-1 capture enzyme immunoassay to determine recent HIV infections by testing remnant serum from persons newly diagnosed with HIV. A population-based incidence estimate is calculated using HIV testing data from newly diagnosed cases and imputing for persons unaware of their HIV infection.

Results

For years 2007–2009, respectively, we estimated new infections in LAC to be 2426 (95% CI 1871–2982), 1669 (CI 1309–2029) and 1898 (CI 1452–2344) (p<0.01); in SF for 2006–2009, 492 (CI 327–657), 490 (CI 335–646), 458 (CI 342–574) and 367 (CI 261–473) (p = 0.14); and in the remaining California counties in 2008–2009, 2526 (CI 1688–3364) and 2993 (CI 2141–3846) respectively. HIV infection rates among men who have sex with men (MSM) in LAC were 100 times higher than other risk populations; the SF MSM rate was 3 to 18 times higher than other demographic groups. In LAC, incidence rates among African-Americans were twice those of whites and Latinos; persons 40 years or older had lower rates of infection than younger persons.

Discussion

We report the first HIV incidence estimates for California, highlighting geographic disparities in HIV incidence and confirming national findings that MSM and African-Americans are disproportionately impacted by HIV. HIV incidence estimates can and should be used to target prevention efforts towards populations at highest risk of acquiring new HIV infections, focusing on geographic, racial and risk group disparities.