bluuebunny/crossref_metadata_2025 huggingface dataset:
Clay Mineralogy of Surface Sediments in the Three Gorges Reservoir: Implications for Sediment Provenances and Weathering Regimes
Authors: Wang Shuai , Rao Wenbo , Qian Jin , He Mengying , Mao Changping , Li Kun , Feng Yuexing , Zhao Jianxin
Published: January 2021

Knowledge of clay mineralogy is essential for understanding the source areas and weathering environments of fluvial sediments, particularly in large reservoirs facing serious problems with sediment deposition, such as the Three Gorges Reservoir (TGR) in east-central China. The purpose of the present study was to identify the sediment provenances and weathering regimes contributing to the sediment load in the TGR by determining the clay-mineral and geochemical compositions of surface sediments during various seasons. X-ray diffractometry and scanning electron microscopy (SEM) were used to identify the clay minerals. The results showed that illite was the dominant mineral, followed in order by kaolinite, chlorite, and montmorillonite. From a mineralogical perspective, distal sources were the main contributors to the TGR sediments, and regional sources (surrounding tributaries) also contributed much during the three seasons, while proximal sources (hillslope soils) supplied sediment in the flood season but not in the other two seasons. The geochemical and hydrological data generally supported the mineralogical results. In the flood season, the chemical indices of the TGR sediments were >0.4, showing that the sediments contained Al-rich illite minerals and experienced intense hydrolysis. In the other two seasons the TGR sediments were enriched in Fe- and Mg-rich illite minerals, resulting from strong physical weathering. Furthermore, precipitation, rather than air temperature or latitude, was the factor that controlled weathering intensity. These findings provide deep insights into the sediment cycle and chemical weathering in this large reservoir basin.
Sensor-based pavement diagnostic using acoustic signature for moduli estimation
Authors: Cafiso Salvatore , Di Graziano A. , Fedele R. , Marchetta V. , Praticò F.
Published: January 2021

The diffusion of smart infrastructures for smart cities provides new opportunities for the improvement of both road infrastructure monitoring and maintenance management.

Often pavement management is based on the periodic assessment of the elastic modulus of the bound layers (i.e., asphalt concrete layers) by means of traditional systems, such as Ground Penetrating Radar (GPR) and Falling Weight Deflectometer (FWD). Even if these methods are reliable, well-known, and widespread, they are quite complex, expensive, and are not able to provide updated information about the evolving structural health condition of the road pavement. Hence, more advanced, effective, and economical monitoring systems can be used to solve the problems mentioned above.

Consequently, the main objective of the study presented in this paper is to present and apply an innovative solution that can be used to make smarter the road pavement monitoring. In more detail, an innovative Non-Destructive Test (NDT)-based sensing unit was used to gather the vibro-acoustic signatures of road pavements with different deterioration levels (e.g. with and without fatigue cracks) of an urban road. Meaningful features were extracted from the aforementioned acoustic signature and the correlation with the elastic modulus defined using GPR and FWD data was investigated.

Results show that some of the features have a good correlation with the elastic moduli of the road section under investigation. Consequently, the innovative solution could be used to evaluate the variability of elastic modulus of the asphalt concrete layers, and to monitor with continuity the deterioration of road pavements under the traffic loads.
The Maine Rx Prescription Drug Plan and the Dormant Commerce Clause Doctrine: The Case of the Missing Link[age]
Authors: Denning Brannon P.
Published: January 2021

In the 2002 Term, the U.S. Supreme Court will hear the case of Pharmaceutical Research and Manufacturers of America (PhRMA) v. Concannon, in which PhRMA, the plaintiff-appellant, will argue that the State of Maine's program to supply low-cost prescription drugs to its citizens (the Maine Rx Program) violates the dormant Commerce Clause doctrine. After the Program became law in 2000, PhRMA sought and obtained an injunction from a federal district court preventing the law from going into effect. Shortly thereafter, the First Circuit unanimously reversed the district court and lifted the injunction. In June 2002, the Supreme Court granted certiorari.

This Article argues that the Maine Rx Program violates the dormant Commerce Clause doctrine because it links a facially nondiscriminatory tax with a subsidy in a way that, in combination, burdens out-of-state drug sellers. The Supreme Court has found similar programs to be invalid in past cases, most recently in the 1994 case West Lynn Creamery, Inc. v. Healy.
A New Concept to Measure the Ambipolar Electric Field Driving Ionospheric Outflow
Authors: Li Kun , Haaland Stein , Wei Yong
Published: January 2021

Over the last few decades, the role of ionospheric outflow for the loss of atmospheric constituents, as a plasma supplier to the magnetosphere and hence for the evolution of the Earth’s atmosphere has been recognized. A substantial amount of the outflow is thought to be caused by the presence of an ambipolar electric field aligned with the open magnetic field lines of the polar region. To better understand how the changes in outflow are influenced by the solar and geomagnetic activity, it is critical to get a better understanding of the impact of this electric field, and to be able to measure it under various conditions. However, such measurements are not possible with present techniques. In this paper, we propose a new technique to measure the tiny electric field. This technique builds on existing instrument technology but extends the capability to measure the very small electric fields. We present the underlying design concept and demonstrate that this concept is viable and able to measure the very small ambipolar electric fields thought to play a key role in the polar wind.
Grazing incidence fast atom diffraction, similarities and differences with thermal energy atom scattering (TEAS)
Authors: Debiossac Maxime , Pan Peng , Roncin Philippe
Published: January 2021

In the elastic regime, GIFAD is equivalent to TEAS with an effective energy E⊥ between 1 meV and 1 eV providing a high sensitivity to topology and to attractive forces. The inelastic regime merges to the classical limit and is still in development.
Tuning spin-crossover transition temperatures in non-symmetrical homoleptic meridional/facial [Fe(didentate)3]2+complexes: what for and who cares about it?
Authors: Deorukhkar Neel , Besnard Céline , Guénée Laure , Piguet Claude
Published: January 2021

The spin transition temperatures of [Fe(didentate)3]2+in acetonitrile (didentate = 2-X-benzimidazole) can be stepwise decreased by 40 K along the series X = pyrazine > pyridine > pyrimidine.
Object-based approach for urban land cover mapping using high spatial resolution data
Authors: Verone Wojtaszek Malgorzata , Ronczyk Levente , Mamatkulov Zokhid , Reimov Mamanbek
Published: January 2021

This paper deals with object-oriented image analysis applied for an urban area. Very high-resolution images in conjunction with object-oriented image analysis have been used for land cover detection. Using the eCognition software with object-oriented methods, not only the spectral information but also the shape, compactness and other parameters can be used to extract meaningful objects. The spectral and geometric diversity of urban surfaces is a very complex research issue. It is the main reason why additional information is needed to improve the outcome of classification. The most consistent and relevant characteristic of buildings is their height. Therefore, elevation data (converted from LIDAR data) are used for building extraction, segmentation and classification. The study deals with the problem, how to determine the most appropriate parameters of segmentation, feature extraction and classification methods. The data extraction includes two phases, the first part consists the following steps: data pre-processing, rule set development, multi-scale image segmentation, the definition of features used to map land use, classification based on rule set and accuracy evaluation. The second part of the data process based on classical raster analysis GIS tools like focal and zonal function.
Creating large-scale maps for agriculture using remote sensing
Authors: Yakubov Gayrat , Mubarakov Khamid , Abdullaev Ilkhomjon , Ruziyev Azizjon
Published: January 2021

Reliable information on the real state of agricultural lands will be required to the development of appropriate measures for the rational use of agricultural lands. To obtain such information, it is necessary to keep permanent and systematic records and inventories of land resources. Large-scale special plans and maps will be required for accounting, inventory and classification of agricultural land. Currently in Uzbekistan such cartographic materials are being created on the scale 1: 10 000 and 1: 25 000 by administrative and territorial units, farms or individual land plots. The article considers the issues of creation of special maps of agricultural land in scale 1:10000 on the example of Sharof Rashidov district of Jizzakh region using remote sensing data with very high spatial resolution KOMPSAT-3.
The role of GIS technology in determining irrigated geosystems
Authors: Ruzikulova Oykhumor , Sabitova Naila , Kholdorova Gulbakhor
Published: January 2021

Irrigated lands of Bukhara, Samarkand and Navoi regions are located in the Zarafshan river oasis and are called geosystems. Assessment of the reclamation state of geosystems of the region has been carried out in the area of classification and mapping for the effective use of land. When classifying a research object, it is much easier to identify, evaluate and apply reclamation measures. In the classification of landscapes, they are grouped in a certain order and there is an opportunity to apply such reclamation measures. So far, the basin-level classification of the Zarafshan river oasis and geosystems has not been carried out. In the scientific paper, landscapes were analysed as a form of geosystem. The geosystems of the region were grouped and summarized for the performance of the reclamation geographical assessment based on water and salt parameters. The classification of the object of study using GIS is of great scientific and practical importance. An analysis of the origin, structure, development and other features of an object when it is classified will determine the scientific significance of the case. Geosystems were isolated using the forms depicted on the relief plastic card in the scientific paper. Measures have been developed to improve the reclamation state of existing geosystems. They reached scientifically sound conclusions.
Monitoring of the Combine with Smart Devices in Soybean Harvesting
Authors: Astanakulov Komil , Abdillaev Tulegen , Umirov Abdigappor , Fozilov Golibjon , Hatamov Bobamurod
Published: January 2021

GIS technology based on real-time smart devices, including GPS devices and sensors will be widely used in agricultural technology. Therefore, this technology is being expected in crop harvesting process. One of the most important processes in soybean cultivation is the efficient use of combines and harvesting without loss of harvest. The grain harvester combine Dominator-130 equipped with GPS receiver and grain level sensor was researched in harvesting the soybean. According to results of experiments, during the harvesting of soybean the grain cleanness in a tank of the combine harvester Dominator-130 made up 95.9 per cent, grain loss in a thresher of combine made up 0.7 per cent, these indexes answer to the demands, however in a reaper of combine harvester the grain loss and damaging of grain were higher than demand. Therefore, it is important to define the optimal technological parameters and working regimes that give opportunity to decrease the loss of grain in the reaper of combine and damaging of grain in the thresher of combine for harvesting the soybean.
Principles of formation of a vehicle’s braking system complex diagnostics
Authors: Liss Michał , Zinko Roman , Polishchuk Oleh , Łukasiewicz Marcin , Betancur German R.
Published: January 2021

On-board diagnostics of technical condition of the brake system elements provide control during the inter-control period of operation. The use of ABS requires further development of on-board diagnostic tools based on the development of new diagnostic methods using multilevel structural and effect schemes, primarily in terms of efficiency parameters. Increase of the information content by increasing the number of measured kinematic parameters and improving the algorithms for generating control signals for the brake system actuators showed effectiveness of diagnostics. To implement diagnostics of technical state of the brake system elements on board of a vehicle, a structural diagram of a diagnostic device, which uses telecommunication means of connection with an expert system and a voltage strain gauge in the coupling device of a truck has been proposed. It is advisable to carry out in-depth element-by-element diagnostics under bench conditions, with the maximum possible exclusion of random factors affecting the process. To summarize all information about the state of the vehicle's braking system, it is necessary to use an expert system.
Diagnosis of multilayer structures and composite parts by multifrequency phase detection
Authors: Musiał Janusz , Horiashchenko Serhiy , Horiashchenko Kostyantin , Wilczarska Joanna
Published: January 2021

The article considers the issue of diagnosing the condition of multilayer elements and structures. Probing methods are considered. A multiphase detection method has been proposed to generate diagnostic information that allows the reflected signals from several consecutive layers to be obtained. The reflection distance is determined for each layer. The presentation of a two-dimensional model of structural sounding in the presence of two objects of study was considered. The three-dimensional model of search of objects of research of concrete designs considered in work provides probing by spherical waves of a detail, measurement of phase shifts of signals reflected from internal objects of research in three points. Division by means of one of mathematical models of signals are reflections from each object of research and determination of coordinates of objects of research and can by means of the mathematical model was represent. The equipment of a measuring instrument was developed to study the analytical multifrequency phase method of distance measurement. This system can be used to diagnose defects in multilayer structures that can transmit radio waves. Also it can be used for quality control of the put coverings and for the analysis of thickness of composite materials, isolation layers in the equipment.
Texas Petawatt laser helps create laboratory conditions like those in a white dwarf star atmosphere
Authors: McConnon Aili
Published: January 2021

An experimental and simulation platform to study warm dense carbon foams achieves temperatures and densities in the laboratory like those found in the atmosphere and envelope of white dwarf stars with carbon lines (DQ dwarf stars)
Thermodynamic characterization shows multicaloric effects make for efficient refrigeration
Authors: Gasparini Allison
Published: January 2021

Calorimeter created to measure the multicaloric response of a nickel-manganese-indium alloy and showed it outperforms single caloric effects.
Understanding the mechanism of ferromagnetism in the semiconductor (Ga,Mn)As
Authors: Bandari Anashe
Published: January 2021

Studying the onset of ferromagnetic ordering will aid in the creation of practical, room-temperature spintronics devices.
Vocabulary depth and its contribution to text quality in the early years of primary school (Profundidad de vocabulario y su contribución a la calidad textual en los primeros años de Educación Primaria)
Authors: Alonso-Cortés-Fradejas M. Dolores , López-Aguado Mercedes , Llamazares-Prieto M. Teresa
Published: January 2021

The purpose of this study is to analyse how vocabulary depth develops in the early years of primary school and to ascertain the effect it has on the quality of the texts produced by the students. A total of 332 Spanish students from the first to fourth grades participated by doing a synonyms/antonyms task to evaluate their vocabulary depth, along with several tasks in which they wrote descriptive texts to evaluate text quality. Vocabulary depth was analysed using a four-dimensional system created ad hoc: change in lexeme, fitting the meaning requested, preservation of syntactic category and degree of conventionality. The text quality indicators were productivity, subordination rate and text organization. The results revealed that both vocabulary depth and the quality of the texts produced improved significantly by grade. The study also found that this type of lexical knowledge contributes significantly to the quality of the texts evaluated. Finally, this article discusses the possible teaching implications of these findings.
Predictors of spelling errors in expository texts written by Hebrew-speaking elementary school children (Predictores de errores ortográficos en textos expositivos escritos por alumnos de habla hebrea en escuela primaria)
Authors: Zadunaisky-Ehrlich Sara , Seroussi Batia , Stavans Anat
Published: January 2021

Spelling errors are considered a paramount criterion in the evaluation of written texts. The present study aimed: (a) to describe the developmental path of spelling errors in expository texts written by Hebrew-speaking children from the second to fifth grades and (b) to reveal the predictive power of cognitive, linguistic and reading variables on spelling accuracy. To this end, each child wrote three expository texts and completed a battery of tasks. Spelling errors were identified and classified into various categories. Findings revealed a consistent decrease in spelling errors as age increased with a greater leap from the third grade on. Proficiency in reading fluency (as measured by rate and accuracy) and good reading comprehension skills significantly reduced the chance of producing spelling errors of any kind. Additional variables, such as lexical knowledge, also contributed to explaining the reduction of spelling errors in content Hebrew words. Our findings of mutual relations clearly support the connectionist and comprehensive approach to spelling that incorporates various linguistic and literacy dimensions in order to reach the goal of correct spelling.
Emergent superconductivity by Re doping in type -II Weyl semimetal NiTe2
Authors: Mandal Manasi , Singh R P
Published: January 2021

Recently topological semimetals emerge as a new platform to realise topological superconductivity. Here we report the emergent superconductivity in single-crystals of Re doped type-II Weyl semimetal NiTe2. The magnetic and transport measurements highlight that Re substitution in Ni-site induces superconductivity at a maximum temperature of 2.36 K. Hall effect and specific heat measurements indicate that Re substitution is doping hole and facilitates the emergence of superconductivity by phonon softening and enhancing the electron-phonon coupling.
TDLAS measurements of temperature and water vapor concentration in a flameless MILD combustor
Authors: Bong Cheolwoo , Lee Jungwun , Sun Hojoong , Yoo Jihyung , Bak Moon Soo
Published: January 2021

We performed non-intrusive tunable diode laser absorption spectroscopy measurements of the temperature (T) and water vapor concentration (X
H2O) on a moderate or intense low-oxygen dilution combustion chamber. The combustor was operating in flameless mode by axially injecting fuel and air at high speeds through separate nozzles, thereby creating a recirculating flow of combusted gas. A pair of water vapor absorption lines near 7185.6 and 7444.36 cm−1 was used to acquire axial absorbance profiles along the height of the combustor. The axial profiles of T and X
H2O were first derived using two-line thermometry measurements. Then the T profiles were estimated from each of the single absorption line measurements by assuming spatial uniformity of X
H2O. Compared to a thermocouple temperature measured at the combustor outlet, the temperatures given by the two-line thermometry were under-estimated whereas the thermocouple temperature was in between the T range given by the single-line thermometry. Importantly, the measurement successfully revealed that the axial profiles of T and X
H2O were mostly flat certainly due to the strong recirculation of the hot combustion gas; however, the different temperature values at a given height implied the existence of a radial temperature gradient in the combustor.
Effect of rhenium on defects evolution behavior in tungsten under irradiation
Authors: Wang Zheng , Gao Liang , Zhu Xiu-Li , Yuan Yue , Wang Shiwei , Cheng Long , Lu Guang-Hong
Published: January 2021

The influence of the transmutation element rhenium (Re) on defect evolution in tungsten (W) during irradiations with heavy ions and deuterium (D) plasma was investigated. Rolled W and W–5Re alloy (Re concentration 5 wt.%) were irradiated with 500 keV iron ions to 0.06 and 0.6 dpa (displacement per atom), and deuterium plasma at 38 eV/D to a fluence of 2.2 × 1025 D m−2 at ∼373 K. The results of Doppler broadening spectroscopy by the positron annihilation technique indicate that more or larger vacancy-type defects were produced in W than in the W–5Re during Fe ion irradiation, suggesting the important role of Re on inhibiting the migration and/or clustering of vacancies. The much smaller and shallower blistering in W–5Re than in W after the same D plasma exposure points to the pinning effects on dislocations by Re. The total retained D amounts in W–5Re and W materials are comparable, but with very different concentration profile at corresponding depth. This is explained by the blister formation exerting influence on the D inward diffusion. Demonstrating the important role of Re on the defect evolution in W under irradiation, the present work provides an enhanced understanding on the possible effects of neutron irradiation on the performance of plasma-facing materials in future fusion devices.
Experimental study of sheath potential coefficient in the J-TEXT tokamak
Authors: ZHAO Wei , NIE Lin , YAN Longwen , XU Min , KE Rui , YANG Jie , CHEN Zhipeng , WANG Zhanhui , WANG Yali
Published: January 2021

Sheath potential coefficient α is a key parameter, which is used to estimate plasma potential (

V

p

) for edge plasma physics study. Recently, a series of experiments has been carried out under hydrogen plasmas in the J-TEXT tokamak with swept probe, which is employed for current–voltage (I–V) characteristic measurement. Electron temperature is evaluated from I–V curve by three-parameter fitting method, and the electron energy probability function shows that electron distribution is Maxwellian both outside and inside of last closed flux surface (LCFS). Plasma potential is obtained by crossing point between I–V exponential fitting curve and electron saturation current extrapolating line, which is in good agreement with first derivative probe technique. The α coefficient profile in the vicinity of the LCFS is obtained, which is in the range of 2.1–3, and decreases from outside to inside of LCFS.
Limits to host colonization and speciation in a radiation of parasitic finches
Authors: Jamie Gabriel A , Hamama Silky , Moya Collins , Kilner Rebecca M , Spottiswoode Claire N
Published: January 2021

Parasite lineages vary widely in species richness. In some clades, speciation is linked to the colonization of new hosts. This is the case in the indigobirds and whydahs (Vidua), brood-parasitic finches whose nestlings mimic the phenotypes of their specific hosts. To understand the factors limiting host colonization and, therefore, speciation, we simulated the colonization of a host using cross-fostering experiments in the field. Despite DNA barcoding suggesting that host species feed their chicks similar diets, nestling Vidua had low survival in their new host environment. Nestling Vidua did not alter their begging calls plastically to match those of the new hosts and were fed less compared to both host chicks and to Vidua chicks in their natural host nests. This suggests that a key hurdle in colonizing new hosts is obtaining the right amount rather than the right type of food from host parents. This highlights the importance of mimetic nestling phenotypes in soliciting feeding from foster parents and may explain why successful colonizations tend to be of hosts closely related to the ancestral one. That nonmimetic chicks are fed less but not actively rejected by host parents suggests how selection from hosts can be sufficiently intense to cause parasite adaptation, yet sufficiently relaxed that parasitic chicks can sometimes survive in and colonize new host environments even if they lack accurate mimetic phenotypes. The difficulties of soliciting sufficient food from novel foster parents, together with habitat filters, likely limit the colonization of new hosts and, therefore, speciation in this parasite radiation.
Changing Disparities in Coronavirus Disease 2019 (COVID-19) Burden in the Ethnically Homogeneous Population of Hong Kong Through Pandemic Waves: An Observational Study
Authors: Yang Bingyi , Wu Peng , Lau Eric H Y , Wong Jessica Y , Ho Faith , Gao Huizhi , Xiao Jingyi , Adam Dillon C , Ng Tiffany W Y , Quan Jianchao , Tsang Tim K , Liao Qiuyan , Cowling Benjamin J , Leung Gabriel M
Published: January 2021

Background

Disparities were marked in previous pandemics, usually with higher attack rates reported for those in lower socioeconomic positions and for ethnic minorities.

Methods

We examined characteristics of laboratory-confirmed coronavirus disease 2019 (COVID-19) cases in Hong Kong, assessed associations between incidence and population-level characteristics at the level of small geographic areas, and evaluated relations between socioeconomics and work-from-home (WFH) arrangements.

Results

The largest source of COVID-19 importations switched from students studying overseas in the second wave to foreign domestic helpers in the third. The local cases were mostly individuals not in formal employment (retirees and homemakers) and production workers who were unable to WFH. For every 10% increase in the proportion of population employed as executives or professionals in a given geographic region, there was an 84% (95% confidence interval [CI], 1–97%) reduction in the incidence of COVID-19 during the third wave. In contrast, in the first 2 waves, the same was associated with 3.69 times (95% CI, 1.02–13.33) higher incidence. Executives and professionals were more likely to implement WFH and experienced frequent changes in WFH practice compared with production workers.

Conclusions

Consistent findings on the reversed socioeconomic patterning of COVID-19 burden between infection waves in Hong Kong in both individual- and population-level analyses indicated that risks of infections may be related to occupations involving high exposure frequency and WFH flexibility. Contextual determinants should be taken into account in policy planning aiming at mitigating such disparities.
GENETIC ANALYSIS OF MURINE ARYLSULFATASE C AND STEROID SULFATASE
Authors: Keinanen Berthie M , Nelson Katherine , Daniel William L , Roque Jose M
Published: January 2021

SWR/J mice possess two- to threefold higher 4-methylumbelliferyl sulfate (4MUS), dehydroepiandrosterone sulfate (DHEAS) and estrone sulfate (E1S) sulfatase activities in liver and kidney extracts than do A/J mice. These interstrain activity differences are maintained throughout the 6- to 45-day postnatal period. Characteristics of the hepatic activities of SWR/J mice suggest that all three activities reside in the same enzyme. Biochemical properties of the SWR/J and A/J enzyme were not significantly different. Expression of hepatic enzyme activity is subject to regulation by an autosomal locus possessing two alleles with additive effects. Postnuclear E1S- and DHEAS-sulfatase activities are primarily microsomal. Although postnuclear hepatic 4MUS-sulfatase activity is predominantly microsomal, renal activity is primarily nonmicrosomal. Only that portion of 4MUS-sulfatase occurring in cell membranes appears capable of hydrolyzing E1S and DHEAS. The hepatic- and renal-specific subcellular distributions of 4MUS-sulfatase activity may reflect tissue differences in enzyme processing. Renal 4MUS-sulfatase activity is also controlled by an autosomal gene with two alleles having additive effects. Positive correlation between hepatic and renal 4MUS-sulfatase activities indicates that both activities are most likely influenced by the same gene.
REGULATION OF ENZYME ACTIVITIES IN DROSOPHILA: GENETIC VARIATION AFFECTING INDUCTION OF GLUCOSE 6-PHOSPHATE AND 6-PHOSPHOGLUCONATE DEHYDROGENASES IN LARVAE
Authors: Cochrane Bruce J , Lucchesi John C , Laurie-Ahlberg C C
Published: January 2021

The genetic basis of modulation by dietary sucrose of the enzyme activities glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) activities in third instar larvae of Drosophila melanogaster was investigated, using isogenic lines derived from wild populations. Considerable genetically determined variation in response was detected among lines that differed only in their third chromosome constitution. Comparison of crossreacting material between a responding and a nonresponding line showed that the G6PD activity variation is due to changes in G6PD protein level. These differences in responses are localized in the fat body, with 300 m m sucrose in the diet resulting in a sixfold stimulation of G6PD activity and a fourfold one of 6PGD in the line showing the strongest response. In this tissue, the responses of the two enzymes are closely correlated with one another. Using recombinant lines, we obtained data that suggested the existence of more than one gene on chromosome III involved in the regulation of G6PD in the fat body, and at least one of these genes affects the level of 6PGD as well.
CODON SUBSTITUTION IN EVOLUTION AND THE "SATURATION" OF SYNONYMOUS CHANGES
Authors: Gojobori Takashi
Published: January 2021

A mathematical model for codon substitution is presented, taking into account unequal mutation rates among different nucleotides and purifying selection. This model is constructed by using a 61 × 61 transition probability matrix for the 61 nonterminating codons. Under this model, a computer simulation is conducted to study the numbers of silent (synonymous) and amino acid-altering (nonsynonymous) nucleotide substitutions when the underlying mutation rates among the four kinds of nucleotides are not equal. It is assumed that the substitution rates are constant over evolutionary time, the codon frequencies being in equilibrium, and, thus, the numbers of synonymous and nonsynonymous substitutions both increase linearly with evolutionary time. It is shown that, when the mutation rates are not equal, the estimate of synonymous substitutions obtained by F. Perler, A. Efstratiadis, P. Lomedico, W. Gilbert, R. Kolodner and J. Dodgson's "Percent Corrected Divergence" method increases nonlinearly, although the true number of synonymous substitutions increases linearly. It is, therefore, possible that the "saturation" of synonymous substitutions observed by Perler et al. is due to the inefficiency of their method to detect all synonymous substitutions.
CLONING AND PHYSICAL MAPPING OF AN EARLY REGION OF THE BACTERIOPHAGE T4 GENOME
Authors: Macdonald Paul M , Mosig Gisela
Published: January 2021

We have cloned DNA restriction fragments from the largely nonessential region of bacteriophage T4 located between genes 39 and 56. The cloned DNA fragments were used to construct a precise map of the sites in this region recognized by eight restriction endonucleases. This restriction map allowed us to compare the cytosine-containing T4 DNA used for cloning with the hydroxymethylcytosine-containing DNA of wild-type T4; there were no detectable rearrangements in the region tested. We were also able to determine the physical locations of several deletion end points and of several genes.
MEIOTIC AND MITOTIC BEHAVIOR OF DICENTRIC CHROMOSOMES IN SACCHAROMYCES CEREVISIAE
Authors: Haber James E , Thorburn Patricia C , Rogers David
Published: January 2021

Meiotic recombination between a circular and a linear chromosome in Saccharomyces cerevisiae has been investigated. The circle was a haploid-viable derivative of chromosome III constructed by joining regions near the two chromosome ends via a recombinant DNA construction: (HMR/MAT-URA3-pBR322-MAT/HML) and was also deleted for MAL2(which therefore uniquely marks a linear chromosome III). Recombination along chromosome III was measured for eight intervals spanning the entire length of the circular derivative. Only 25% of all tetrads from a ring/rod diploid contained four viable spores. These proved to be cases in which there was either no recombination along chromosome III or in which there were two-strand double crossovers or higher order crossovers that would not produce a dicentric chromosome.—At least half of the tetrads with three viable spores included one Ura+ Mal+ spore that was genetically highly unstable. The Ura+ Mal+ spore colonies gave rise to as many as seven genetically distinct, stable ("healed") derivatives, some of which had lost either URA3 or MAL2. Analysis of markers on chromosome III suggests that dicentric chromosomes frequently do not break during meiosis but are inherited intact into a haploid spore. In mitosis, however, the dicentric chromosome is frequently broken, giving rise to a variety of genetically distinct derivatives. We have also shown that dicentric ring chromosomes exhibit similar behavior: at least half the time they are not broken during meiosis but are broken and healed during mitosis.—The ring/rod diploid can also be used to determine the frequency of sister chromatid exchange (SCE) along an entire yeast ring chromosome. We estimate that an unequal number of SCE events occurs in approximately 15% of all cells undergoing meiosis. In contrast, the mitotic instability (and presumably SCE events) of a ring chromosome is low, occurring at a rate of about 1.2 x 10-3 per cell division.
GENETIC HETEROGENEITY OF RABBIT ALPHA-1-ANTITRYPSIN
Authors: Kueppers F , Lee C C , Fox R R , Mills J K
Published: January 2021

Sixteen inbred or partially inbred strains of rabbits were investigated for electrophoretic and quantitative variations of alpha-1-antitrypsin (A-1-AT). We found interindividual differences in the electrophoretic A-1-AT patterns as well as quantitative differences in the concentrations of A-1-AT and the serum trypsin-inhibiting activity.

Three electrophoretic phenotypes were distinguished: M, P and MP. M was characterized by a predominant anodal A-1-AT band, and P had a major cathodal component. The MP pattern can be explained by the occurrence of the M and P components in the same serum due to heterozygosity.

The P pattern was associated with an A-1-AT concentration of approximately 56% of that in sera with the M phenotype. The levels of A-1-AT in sera with the MP phenotype were intermediate between those in M and P types.

In addition to the type-specific quantitative variation, we found a quantitative sexual dimorphism of a moderate degree: Female rabbits had A-1-AT concentrations 16% less than males.
CHARACTERIZATION OF AN Spm-CONTROLLED BRONZE-MUTABLE ALLELE IN MAIZE
Authors: Nelson Oliver E , Klein Anita S
Published: January 2021

The association of a receptor (Rs) of the Spm system with a Bz-1 allele has created a two-element Spm-controlled bz-mutable allele (bz-m13) of maize (Zea mays L.). In the absence of Spm, one copy of bz-m13 (bz/bz/bz-m13) conditions full anthocyanin production in the aleurone layer of the seed. In the presence of this Spm, bz-m13 produces a unique, coarsely variegated seed phenotype and has a high rate (50–83%) of gametic change to stable bz′ or Bz′ derivatives. Even one copy of a Bz′ derivative allele conditions full anthocyanin production in the aleurone, but the enzyme (UFGT) level of the progenitor Bz-1 allele is not restored in most Bz′ derivatives.
A STUDY OF ODD MATING-TYPE DETERMINATION FACTOR BY TRANSFER OF MACRONUCLEAR KARYOPLASM IN PARAMECIUM TETRAURELIA
Authors: Koizumi Sadaaki , Kobayashi Sumiko
Published: January 2021

The unique feature of the "B system" of mating-type determination found in Paramecium tetraurelia is the existence of a cytoplasmic difference between odd (O) and even (E) cells created and maintained by the action of their macronuclei. Thus far, the presence of a determining factor that controls the differentiation of the developing zygotic macronucleus for O mating type has not been verified. Results of crosses between cells of differing clonal age and complementary mating type suggest that, for one to two fissions after autogamy, O cells produce some factor that determines the gametic nucleus (micronucleus) as mating type O. Direct evidence for the production of O-determining factor by the young O macronucleus was obtained by transplanting young O macronuclear karyoplasm (a part of the macronucleus) into E cells: 32-35% of E exautogamous clones transformed to O; transformation of E exautogamous clones to O reached as high as 72% by transfer of young O macronuclear karyoplasm from a conjugant, 3-4 hr after mixing. This indicates that O determinants produced by the O macronucleus can also act during the sensitive period of development of the new macronucleus. These O-determining factors may be produced or activated at the sexual stage and then decrease in activity in subsequent fissions after new macronuclear reorganization.
FACTORS INFLUENCING THE EFFECT OF SEGREGATION DISTORTION IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER
Authors: Temin Rayla Greenberg , Marthas Marta
Published: January 2021

The major components of the SD system have been examined in two natural populations of D. melanogaster to investigate how SD behaves and is maintained in nature and to estimate its impact and efficiency. A twofold approach was used: (1) direct measurements of segregation distortion in wild males and (2) measurement of sensitivity of wild SD  + chromosomes to SD action. Characterization of newly isolated SD chromosomes and of a large number of SD  + chromosomes from nature demonstrated that (1) SD can operate efficiently in the wild genome: 45% of SD/SD  + males collected from nature had k values larger than 0.70. (2) Forty-three of 44 newly recovered SD chromosomes are of the SD-72 type, having a small pericentric inversion that maintains tight linkage among the Sd, E(SD) and Rsp loci in the SD complex. In 1956, most SD chromosomes in Madison lacked this inversion. (3) Only 12 of the 44 SD chromosomes carried a recessive lethal (compared with five of six in 1956), and many of the viable SD chromosomes were fertile as homozygotes, indicating that SD homozygotes need not have obvious reductions in fitness. (4) Among more than 500 wild chromosomes assayed for response to distortion by a strong SD, at least 40-50% were sensitive, about 33% were partially sensitive and 17% were insensitive. This frequency of sensitives is higher than in reports from some other populations. An estimated 12% of the wild chromosomes were classified as true Rspi by their constellation of effects, including a special test of ability to cause self-distortion of a "suicide" chromosome, R(cn)-10. In a direct assay with R(cn)-10, an independent sample of 99 chromosomes from nature gave 30% putative Rspi. Thus, these populations contain in the range of 12-30% Rspi. (5) Chromosomes supersensitive to SD, previously described for certain laboratory stocks, were also found to coexist in nature with SD. (6) Profiles of wild chromosomes with a panel of three or four different SD testers suggest a series of allelic alternatives at the Rsp locus including supersensitive, sensitive, semisensitive and insensitive, and that loci other than Rsp may also be important in determining the effect of SD in nature.
IDENTIFICATION OF MUTATIONS ASSOCIATED WITH MACROFIBER FORMATION IN BACILLUS SUBTILIS
Authors: Saxe Charles L , Mendelson Neil H
Published: January 2021

A search was made for the genes responsible for the production of helical macrofibers in the original collection of macrofiber-producing strains of B. subtilis. Two loci were identified: fibA, located between hisA and tag-1, and fibB, linked to cysB. fibA governs a short-lived division suppression phenomenon associated with the production of rudimentary fibers, whereas fibB appears to be responsible for a persistent division suppression and a more highly organized helical macrofiber. Both mutations are recovered from each of the original macrofiber-producing strains which also carried the div IV-B1 mutation responsible for minicell production. The latter mutation by itself is not sufficient, however, for the production of macrofibers. Other known mutations leading to division suppression that map in the same region are shown not to be allelic to fibA or fibB. Neither fib locus appears to be responsible for helix hand determination.
GENETIC MAPPING OF GENES REQUIRED FOR MOTILITY IN CAULOBACTER CRESCENTUS
Authors: Ely Bert , Croft Ronda H , Gerardot Connie J
Published: January 2021

Mutations in more than 30 genes affect motility in Caulobacter crescentus. We have determined the chromosomal map locations for 27 genes involved in flagellar morphogenesis (fla), three genes involved in flagellar function (mot), and three genes that have a pleiotropic effect on both motility and bacteriophage resistance (ple). Three multigene clusters have been detected at widely separated chromosomal locations, but in addition, there are 12 fla and mot genes that are found at eight additional sites scattered around the C. cresentus chromosome. Thus, there is more scatter of genes involved in flagellar structure and function than has been observed in other bacterial systems.
SACCHAROMYCES CEREVISIAE RECESSIVE SUPPRESSOR THAT CIRCUMVENTS PHOSPHATIDYLSERINE DEFICIENCY
Authors: Atkinson Katharine D
Published: January 2021

Phenotypic reversion of six independent Saccharomyces cerevisiae cho1 mutants was shown to be due predominantly to mutation of an unlinked gene, eam1. The eam1 gene was located very close to ino1 on chromosome X by meiotic tetrad analysis. Recessive eam1 mutations did not correct the primary cho1 defect in phosphatidylserine synthesis but made endogenous ethanolamine available for sustained nitrogenous phospholipid synthesis. A novel biochemical contribution to nitrogenous lipid synthesis is indicated by the eam1 mutants.
TECHNIQUES FOR MANIPULATING CHROMOSOMAL REARRANGEMENTS AND THEIR APPLICATION TO DROSOPHILA MELANOGASTER. II. TRANSLOCATIONS
Authors: Craymer Loring
Published: January 2021

Translocations have long been valued for their segregational properties. This paper extends the utility of translocations by considering recombinational derivatives of pairs of simple reciprocal translocations. Three major derivative structures are noted. One of these derivatives is suitable for use in half-tetrad experiments. A second should find use in recombining markers with translocation breakpoints. The third is an insertional-tandem duplication: it has a section of one chromosome inserted into a heterologue with a section of the latter chromosome tandemly repeated about the breaks of the insert. All of these structures are contained in "constellations" of chromosomes that regularly segregate aneuploid-1 products (informationally equivalent to nonrecombinant adjacent-1 segregants) for one of the parental translocations but do not segregate euploid products. This is in contrast to the parental T  1/T  2 constellations which segregate euploid products but not aneuploid-1 products. Methods are described for selecting translocation recombinants on the basis of this dichotomy. Several examples of translocation recombinants have been recovered with these techniques, and the recombination frequencies seem to be consistent with those observed for crossovers between inversion breakpoints. Recombinant chromosomes tend to disjoin, but it is observed that the tendency may vary according to the region involved in the recombination, and it is suggested that this difference reflects a difference in chiasmata terminalization times. Special consideration is given to insertional-tandem duplications. Large insertional-tandem duplications are useful in cytogenetic screens. Small insertional-tandem duplications are useful in gene dosage studies and other experiments that require an insert from one chromosome to another. Large duplications can be deleted to form small duplications. To generate a small insert for a specified region, it is only necessary to have one translocation with a breakpoint flanking the region of interest. The second translocation can have a breakpoint quite far from the region: an insertional-tandem duplication containing the region that has one closely flanking breakpoint can be deleted to create a smaller duplication that has two closely flanking breakpoints.
COMPONENTS OF SELECTION IN X CHROMOSOME LINES OF DROSOPHILA MELANOGASTER: SEX RATIO MODIFICATION BY MEIOTIC DRIVE AND VIABILITY SELECTION
Authors: Curtsinger James W
Published: January 2021

Selection coefficients and segregation parameters have been estimated in 18 randomly chosen lines carrying wild Χ chromosomes on the cn bw genetic background. Each line was studied in replicated crosses of four types, with approximately 100 replications per line per cross. Crosses in which male Χ chromosomes differed exhibited significant sex ratio heterogeneity. Maximum likelihood estimation of segregation parameters revealed two lines in which the proportion of Χ-bearing gametes produced by males was significantly different from Mendelian expectations. These observations suggest that segregation distortion is a common feature of naturally occurring genetic variation. Non-Mendelian segregation has important evolutionary implications.
ADAPTATION AT SPECIFIC LOCI. IV. DIFFERENTIAL MATING SUCCESS AMONG GLYCOLYTIC ALLOZYME GENOTYPES OF COLIAS BUTTERFLIES
Authors: Watt Ward B , Carter Patrick A , Blower Sally M
Published: January 2021

Male mating success as a function of genotype is an important fitness component. It can be studied in wild populations, in species for which a given group of progeny has exactly one father, by determining genotypes of wild-caught mothers and of sufficient numbers of their progeny. Here, we study male mating success as a function of allozyme genotype at two glycolytic loci in Colias butterflies, in which sperm precedence is complete, so that the most recent male to mate fathers all of a female's subsequent progeny.—For the phosphoglucose isomerase, PGI, polymorphism, we predict mating advantage and disadvantage of male genotypes based on evaluation of their biochemical functional differences in the context of thermal-physiological-ecological constraints on the insects' flight activity. As predicted, we find major, significant advantage in mating success for kinetically favored genotypes, compared to the genotype distribution of males active with the sampled females in the wild. These effects are repeatable among samples and on different semispecies' genetic backgrounds.—Initial study of the phosphoglucomutase, PGM, polymorphism in the same samples reveals heterozygote advantage in male-mating success, compared to males active with the females sampled. This contrasts with a lack of correspondence between PGI and PGM genotypes in other fitness index or component differences.—Epistatic interactions in mating success between the two loci are absent.—There is no evidence for segregation distortion associated with the alleles of either primary locus studied, nor is there significant assortative mating.—These results extend our understanding of the specific variation studied and suggest that even loci closely related in function may have distinctive experience of evolutionary forces. Implications of the specificity of the effects seen are briefly discussed.