Nematode Memory: Now,Where Was I?

The nematode Caenorhabditis elegans is able to use tastes, smells and temperature to locate food. New data show that worms can also detect the level of oxygen in the environment and migrate towards an oxygen level associated with food.     

Was istAcrosiphonia arcta?

No answer to this question is presented in this article. Two species, morphologically alike, differ in their life-cycles. One of these species has hitherto been found only once in a culture ofSpongomorpha aeruginosa, which was started using zoospores ofCodiolum petrocelidis. It has never been found in natural environments at Helgoland. This species has a heteromorphic life-cycle: a monoecious gametophyte which alternates with a unicellular sporophytical stage. Gametes do not develop parthenogenetically. The other species is a monoecious diplont, common at Helgoland and designated asAcrosiphonia arcta. It will not be possible to assign a name to these forms unless life-cycles of species from type-localities have been studied. In general, life-cycles are not significant for the characterization of units higher than genera. The order of Acrosiphoniales is characterized by operculate sporangia and gametangia respectively, as well as by the shape of the vegetative thallus.     

Was August Weismann right?

A new hypothesis of the genetic regulation of cell differentiation is put forward. The hypothesis is based on the assumption that the diminution and hyper-replication patterns of repetitive nucleotide sequences depend on the differentiation pathways of cells and tissues.     

Was steuert das Pflanzenwachstum?

What controls plant growth? Although, photosynthesis is essential for plant growth, photosynthetic carbon acquistion rarely controls the rate of growth. Tissue formation (structural growth) is rather directly and more strongly controlled by the availability of water and nutrients as well as by temperature, so that the rate of tissue formation controls the amount of photoassimilates that can be invested in growth (and is produced in the first place).     

What Was Huxley's Epiphenomenalism?

Thomas Huxley is often identified as the originator of the doctrineknown as ``epiphenomenalism,' but there appears to be littleappreciation for the details of Huxley's theory. In particular,conflicting interpretations show that there is uncertainty about twoaspects of his position: whether mental states are completelywithout causal powers or simply have no influence on the behavior theyare typically taken to explain, and whether conscious epiphenomena arethemselves physical states of the brain or immaterial items. I clarifythese issues and show that Huxley's brand of epiphenomenalism is in factdifferent from the forms usually attributed to him.     

Was Darwin a creationist?

Throughout the Origin of Species, Darwin contrasts his theory of natural selection with the theory that God independently created each species. This makes it seem as though the Origin offers a scientific alternative to a theological worldview. A few months after the Origin appeared, however, the eminent anatomist Richard Owen published a review that pointed out the theological assumptions of Darwin's theory. Owen worked in the tradition of rational morphology, within which one might suggest that evolution occurs by processes that are continuous with those by which life arises from matter; in contrast, Darwin rested his account of life's origins on the notion that God created one or a few life forms upon which natural selection could act. Owen argued that Darwin's reliance on God to explain the origins of life makes his version of evolution no less supernatural than the special creationist that Darwin criticizes: although Darwin limits God to one or a few acts of creation, he still relies upon God to explain life's existence.     

Was ferrocyanide a prebiotic reagent?

Hydrogen cyanide is the starting material for a diverse array of prebiotic syntheses, including those of amino acids and purines. Hydrogen cyanide also reacts with ferrous ions to give ferrocyanide, and so it is possible that ferrocyanide was common in the early ocean. This can only be true if the hydrogen cyanide concentration was high enough and the rate of reaction of cyanide with ferrous ions was fast enough. We show experimentally that the rate of formation of ferrocyanide is rapid even at low concentrations of hydrogen cyanide in the pH range 6–8, and therefore an equilibrium calculation is valid. The equilibrium concentrations of ferrocyanide are calculated as a function of hydrogen cyanide concentration, pH and temperature. The steady state concentration of hydrogen cyanide depends on the rate of synthesis by electric discharges and ultraviolet light and the rate of hydrolysis, which depends on pH and temperature. Our conclusions show that ferrocyanide was a major species in the prebiotic ocean only at the highest production rates of hydrogen cyanide in a strongly reducing atmosphere and at temperatures of 0°C or less, although small amounts would have been present at lower hydrogen cyanide production rates. The prebiotic application of ferrocyanide as a source of hydrated electrons, as a photochemical replication process, and in semi-permeable membranes is discussed.     

Was ist Ipomoea violacea L.?

Ipomoea violacea L. is lectotypified by one of the plates which were copied for Boerhaave from Plumier's “Botanicon Americanum”. The synonymy of this species also is discussed.     

“I Spent a Full Month Bleeding,I Thought I Was Going to Die…” A Qualitative Study of Experiences of Women Using Modern Contraception in Wakiso District,Uganda

Introduction

There is high unmet need for family planning (FP) in Uganda as well as high contraceptive discontinuation rates. These contribute to the high fertility rates that in part are due to unplanned pregnancies. There are gaps in knowledge about experiences that couples go through while using contraceptives in their lives. This study explored women’s experiences during the course of their contraceptive use.

Methods

We conducted a qualitative study involving 30 women who had used modern contraception for at least one year in Wakiso district, central Uganda. We used in-depth interviews to obtain their personal accounts. Index women were approached through health officers at four health centres in the district. All ethical approvals and informed consent were obtained. We used conventional content analysis; identifying codes through open coding, on which basis categories were developed and grouped into overarching themes.

Results

Women’s accounts were summarised in the following themes: negative experiences with modern contraceptive use, motivation to continue using FP in spite of these negative experiences, the role of influential people, and discontinuation of use. Negative accounts dominated the experiences of most women but they expressed strong desire to continue using modern contraception even amidst all challenges. Health workers emerged as the most influential people that played a vital role in women’s decisions.

Conclusion

Varied negative experiences with modern contraception and misperceptions exist amidst a determination to continue use. Partner engagement, health service strengthening to improve side effects management and health worker skills, and engaging older women that have successfully used contraception as community champions, are potential strategies to support women’s contraceptive decisions.     

Was the ASN a Myelin Society?

Neurochemical Research -     

Was istMelanerpes hargitti Dubois?

Zusammenfassung Der Typus vonMelanerpes hargitti, vonAlphonse Dubois im Jahre 1899 beschrieben, befindlich im Kön. Naturhist, Museum zu Brüssel, ist nichts anderes als einMelanerpes cruentatus mit schwach entwickeltem Augenstreif, der nicht bis zum Auge reicht, sondern etwas oberhalb des Auges endet.Ein ähnliches Stück aus Surinam, das im Leidener Museum aufbewahrt wird, wird beschrieben.Es wird aufmerksam gemacht auf die Häufigkeit von Übergängen zwischencruentatus undrubrifrons. Die Biologie beider ist gleich, ebenso ihre Stimme. Beide kommen in gemischten Trupps vor. Da fernerrubrifrons nirgends allein vorkommt, muß er als eine Variante (Morphe) voncruentatus aufgefaßt werden und nicht als eine selbständige Art.     

Was our ancestor a hyperthermophilic procaryote?

In this paper we critically review the 'classical' model for the emergence of the three domains (Archaea, Bacteria, Eucarya), which presents hyperthermophilic procaryotes as the ancestors of all life on this planet. We come to the conclusion that our last common ancestor is likely to have been rather a non-hyperthermophilic protoeucaryote endowed with sn-1,2 glycerol ester lipids (as in modern Bacteria and Eucarya), from which Archaea emerged by streamlining under pressure for adapting to heat, a process which involved an important molecular innovation: the advent of sn-2,3 glycerol ether lipids. The nature of the primeval bacterial lines of descent is less clear; it would appear, nevertheless, that the first extreme- and hyperthermophilic Bacteria emerged by converging mechanisms; lateral gene transfer from Archaea may have played a role in this adaptation.