Pliocene-Pleistocene Boundary in Deep-Sea Sediments: Extinctions and evolutionary changes in microfossils clearly define the abrupt onset of the Pleistocene

For a hundred years students of the Pleistocene have looked for evidence of the climatic change which initiated the Pleistocene epoch. Glacial deposits on the continents have been of little help because of their discontinuity and because of the destructive effect of later glaciations. Hence, Pleistocene geologists have turned to the uplifted Pliocene-Pleistocene marine sediments of the Mediterranean region. In the absence of evidence of a single, clearly defined climatic change in this sedimentary section, they have agreed to define the beginning of the Pleistocene by the first appearance of Anomalina baltica, a species of benthic Foraminifera tolerant of cool water. This definition leaves much to be desired: It rests on a single benthic species whose areal distribution must have been partly determined by local conditions on the sea floor; it is useless outside of the Mediterranean region; and there is no convincing evidence that the first appearance of Anomalina baltica in the Mediterranean coincided with the onset of the first glaciation.     

Paleontological Evidence of Varitions in Length of Synodic Month since Late Cambrian

The values of length of synodic month, obtained from tidally controlled periodical growth patterns in mollusks and stromatolites for several geologic periods, indicate that the deceleration rate of the earth's rotation has not been constant. Two breaks in slope, in the Pennsylvanian and Cretaceous, may be related to changes in distribution of continents, oceans, and adjacent shallow seas.     

The current situation in mexican immigration

By 1988, the Mexican-origin population of the United States had grown to 12.1 million, largely from recent, sharp increases in immigration. The policy concerns raised by this phenomenon have been influenced by some perceptions that available research contradicts. Today most Mexican immigrants come to stay, about half are female, and they have increasingly less schooling compared to the native-born population and other immigrants. Nationally, they do not cause adverse economic effects for native-born workers and, across generations, their language and political assimilation is proceeding well. They put greater demands on education than on other public services. However, the Mexican-origin population affects the economy and public services more and differently in the areas where it is concentrated, primarily in the western United States and large urban areas. Further, the recent legalization of 2.3 million Mexican immigrants can be expected to increase the demand on public services, especially in those areas.     

Role of adenine nucleotide translocator 1 in mtDNA maintenance

Autosomal dominant progressive external ophthalmoplegia is a rare human disease that shows a Mendelian inheritance pattern, but is characterized by large-scale mitochondrial DNA (mtDNA) deletions. We have identified two heterozygous missense mutations in the nuclear gene encoding the heart/skeletal muscle isoform of the adenine nucleotide translocator (ANT1) in five families and one sporadic patient. The familial mutation substitutes a proline for a highly conserved alanine at position 114 in the ANT1 protein. The analogous mutation in yeast caused a respiratory defect. These results indicate that ANT has a role in mtDNA maintenance and that a mitochondrial disease can be caused by a dominant mechanism.     

Galaxies, human eyes, and artificial neural networks

The quantitative morphological classification of galaxies is important for understanding the origin of type frequency and correlations with environment. However, galaxy morphological classification is still mainly done visually by dedicated individuals, in the spirit of Hubble's original scheme and its modifications. The rapid increase in data on galaxy images at low and high redshift calls for a re-examination of the classification schemes and for automatic methods. Here are shown results from a systematic comparison of the dispersion among human experts classifying a uniformly selected sample of more than 800 digitized galaxy images. These galaxy images were then classified by six of the authors independently. The human classifications are compared with each other and with an automatic classification by an artificial neural network, which replicates the classification by a human expert to the same degree of agreement as that between two human experts.     

Radio Frequency Signals in Jupiter's Atmosphere

During the Galileo probe's descent through Jupiter's atmosphere, under the ionosphere, the lightning and radio emission detector measured radio frequency signals at levels significantly above the probe's electromagnetic noise. The signal strengths at 3 and 15 kilohertz were relatively large at the beginning of the descent, decreased with depth to a pressure level of about 5 bars, and then increased slowly until the end of the mission. The 15-kilohertz signals show arrival direction anisotropies. Measurements of radio frequency wave forms show that the probe passed through an atmospheric region that did not support lightning within at least 100 kilometers and more likely a few thousand kilometers of the descent trajectory. The apparent opacity of the jovian atmosphere increases sharply at pressures greater than about 4 bars.     

Delay of disease development in transgenic plants that express the tobacco mosaic virus coat protein gene

A chimeric gene containing a cloned cDNA of the coat protein (CP) gene of tobacco mosaic virus (TMV) was introduced into tobacco cells on a Ti plasmid of Agrobacterium tumefaciens from which tumor inducing genes had been removed. Plants regenerated from transformed cells expressed TMV mRNA and CP as a nuclear trait. Seedlings from self-fertilized transgenic plants were inoculated with TMV and observed for development of disease symptoms. The seedlings that expressed the CP gene were delayed in symptom development and 10 to 60 percent of the transgenic plants failed to develop symptoms for the duration of the experiments. Increasing the concentration of TMV in the inoculum shortened the delay in appearance of symptoms. The results of these experiments indicate that plants can be genetically transformed for resistance to virus disease development.     

Larval diet affects development and reproduction of East Asian strain of the fall armyworm,Spodoptera frugiperda

In December 11, 2018, the fall armyworm(FAW), Spodoptera frugiperda invaded China and has since impacted local maize, sorghum and other crops. Here, we draw on laboratory experiments to show how different host crops(i.e., maize, sorghum, wheat and rice) and artificial diet affect larval growth and adult reproduction of one local FAW strain. Larval diet affected development duration, pupation rate, survival and emergence rate of pupae, and S. frugiperda adult fecundity. FAW attained the slowest larval development(19.4 days) on sorghum and the fastest(14.1 days) on artificial diet, with larvae attaining 99.6% survival on the latter food item. On rice, FAW larvae attained survival rate of 0.4% and were unable to pupate successfully. Pupation rate and pupal survival varied substantially between artificial diet and live plantlets at different phenological stages. Pupal weight was the highest(0.26 g) on artificial diet and the lowest(0.14 g) on sorghum, while FAW females reached the highest fecundity(699.7 eggs/female) on 2-leaf stage maize. Egg hatching rate equaled 93.6% on 4-or 5-leaf stage maize and 36.6% on artificial diet. FAW intrinsic rate of natural increase and the finite rate of increase varied between larval diets, reflecting how young maize leaves are the most suitable diet. Our findings can help to refine laboratory rearing protocols, devise population forecasting models or guide the deployment of ‘area-wide' integrated pest management(IPM) modules in FAW-invaded areas of China and other Asian countries.     

Analytical methods for quality control of propolis

Propolis is a resinous substance collected by honeybees from leaf buds and cracks in the bark of various plants, and it is composed of 50% resin (composed of flavonoids and related phenolic acids), 30% wax, 10% essential oils, 5% pollen and 5% various organic compounds. Propolis cannot be used as raw material, and it must be purified by extraction with solvents. This process should remove the inert material and preserve the polyphenolic fraction, which is considered to contribute more to the observed healing effects than the other propolis constituents. Therefore, the assay of propolis polyphenols is of interest, and this paper describes the results obtained in the analysis of propolis by means of a gradient HPLC or mass spectrometry. HPLC in the gradient mode and coupled with photodiode array detection remains the method of choice for the assay of most relevant components of propolis. Direct analysis by APCI-IT-MS represents a valuable alternative to obtain typical fingerprints of propolis and a reliable identification of a large number of propolis components.