The spatial dynamics of U.S. fertility, 1970-1990

The fertility downturn in the U.S. since the baby boom has been accompanied by a growing divergence in regional fertility rates. This paper examines the spatial implications of recent fertility trends. Two interrelated questions are posed. First, how and why have the time trends in fertility varied spatially? Second, how have the regional patterns of fertility changed over time? These questions are investigated using a continuous spatio-temporal model of U.S. fertility built using the Dual Expansion Method. Results indicate that the pace of fertility decline has been the most rapid in the Northeast and the slowest in the West. Further, the traditional North-South distinctions in fertility rates are being replaced by East-West patterns. These changes tentatively suggest that regional ethnic composition is becoming an increasingly important factor in accounting for the spatial variation of U.S. fertility.     

贵州兰科一新纪录属种(独花兰属:独花兰)

报道了兰科植物1贵州分布新纪录属和新纪录种,即独花兰属(Changnienia S.S.Chien)和独花兰(Changnieniaamoena S.S.Chien).研究所用标本保存在贵州科学院梵净山生态站和梵净山国家级自然保护区管理局.     

Dynamics of the U.S. interstate migration system, 1975-1992

This note further develops an analysis of the U.S. interstate migration system by K.E. McHugh and P. Gober. Specifically, it uses annual state-to-state migration flow data from Internal Revenue Service for the period 1975-1992 to analyze migration trends. Some modifications to earlier conclusions are suggested. "First the note concludes that the emergence of a new pattern of population redistribution in the U.S. in the 1980s, as reported by McHugh and Gober, was indeed significant, but that it was transitory. Second, the note's analysis does not support McHugh and Gober's conclusion of a fairly strong inverse relationship between migration effectiveness and economic expansions and contractions."     

Resistance to potato late blight (Phytophthora infestans (Mont.) de Bary) in Solanum nigrum,S. villosum and their sexual hybrids with S. tuberosum and S. demissum

Summary Solanum nigrum and S. villosum, and their sexual hybrids with S. tuberosum and S. demissum respectively, were inoculated with a complex race of Phytophthora infestans. No visible reaction was seen on S. villosum and one genotype of S. nigrum. Another genotype of S. nigrum and the hybrids showed a hypersensitive response on most inoculated leaves. In one experiment, some sporulation was observed on detached leaves of a hybrid derived from S. nigrum. Microscopical examination of infections in S. nigrum and in a hybrid from S. nigrum, showed that penetration of epidermal cells and subsequent intercellular growth of the pathogen into the spongy mesophyll occurred, but without the formation of haustoria, and that invaded and neighbouring cells became necrotic. Callose appositions were found in epidermis and mesophyll cells of all inoculated genotypes, and also in epidermal cells of the unrelated nonhost species Brassica campestris.     

Short-term dynamics of the U.S. interstate migration system, 1980-1988

"This paper identifies short-term fluctuations in the [U.S.] interstate migration system using annual state-to-state migration flow data from Internal Revenue Service (IRS) records for the period, 1980 to 1988. Measures of migration efficiency are employed to indicate the net redistribution of population between states relative to the size of underlying gross interstate flows. Three findings stand out: (1) migration was more effective in redistributing the population in years of economic retrenchment than during periods of growth and expansion, (2) the dominant pattern of population redistribution shifted from a core-periphery configuration evident in the 1970s and early 1980s to a bi-coastal distribution by the mid-1980s, and (3) the most dramatic event of the 1980s was the oil glut and decline in oil prices and profits which ravaged the economies of energy states in the West South Central and Mountain regions....Overall, results demonstrate the high degree of temporal and spatial volatility in the U.S. interstate migration system."     

Investment,Capital Stocks and the Age of Capital in U.S. Regions

ABSTRACT This paper outlines a conventional method of constructing regional capital stocks using investment and depreciation data. The method was used to estimate annual capital stocks for twenty (two-digit SIC) manufacturing industries in the nine census regions of the US. between 1955 and 1989. The novelty of the paper is the disaggregated capital stock data generated. Those data reveal that the industrial distribution of capital is becoming increasingly similar among regions of the U.S. They also show the familiar snowbelt-sunbelt shift of manufacturing capacity. Statistical tests establish that the redistribution of regional net capital stocks between 1955 and 1989 is significant in sixteen of twenty industries and that in ten of these sectors the most pronounced shifts in capacity occurred before the early 1970s. As investment moved away from the old manufacturing heartland, the age of capital in the mid Atlantic and east north central states increased and the age structure of capital stocks became relatively youthful in the west. Age pyramids reveal that regional variations in the age distribution of capital and the average age of capital were greater in 1989 than in 1955. Models of embodied technological change claim that the age of capital is a useful surrogate of best-practice technology.     

The U.S.-Canada Free Trade Agreement and Commodity Transportation Services among U.S. States

The Free Trade Agreement (FTA) implemented beginning in 1989 by the United States aid Canada will have significant impacts on bilateral trading patterns. In addition to its long-term, investment-related repercussions, the FTA will affect the volume, commodity composition, and spatial distribution of trade and, consequently, the transportation services required to move commodities between the two nations. This paper examines the changing spatial structure of U.S.-Canadian trade under the FTA. It employs commodity-specific analyses of tariffs and non-tariff barriers, as well as price and income elasticities of demand, to estimate sectoral and special changes among U.S. states in total, land, water, and airborne commodity flows since 1988 attributable to the FTA. The analysis details the assumptions and methodology used, elaborates upon the likely consequences for me nation's ten largest customs districts, particularly New York, and concludes with some comments on other forces that may alter the expected results.     

Race,Place, and the Persisting Income Divide in the U.S. Southeast, 2000–2014

Despite economic growth since the recession, the gap between the richest and the poorest segments of the population remains one of the most pressing concerns of contemporary America. This paper uses IR‐95/20, IR‐80/20, and IR‐65/35 ratios to measure the income divides between the richest and the poorest segments in the mid‐to‐large‐sized metropolises of the U.S. Southeast, their variation across ethnicities, and their association with metropolitan level attributes such as diversity, segregation, socio‐economic, and other built‐environment, and labor characteristics. The income divide ratios serve as the dependent variables whereas principal components along with state‐dummy variables serve as the explanatory variables in regressions analyses. The metropolises that are large, diverse, and better educated are the most income‐divided whereas those with lower educated people are less divided. Metropolises with larger shares of their labor engaged in primary sectors of economy have higher income divides; this observation also holds true for African Americans and Hispanics. Metropolises that gained in intermixing during 2000–2014 are associated with a lower income divide and vice versa.     

U.S. Economic Growth vs. Environmental Conditions

A widely-held belief is that stricter environmental regulations stifle economic growth. To determine empirically the effect of environmental conditions and policies on state-level per capita income growth, a Barro-type economic growth model was estimated for the years 1982 to 1991, which correspond to two consecutive troughs in the business cycle. States with better environmental conditions had significantly higher income growth rates during this period. At the same time, stricter environmental policies did not significantly depress income growth. Data used include recently developed, consistent measures of environmental policy and quality for individual states, as well as data from the 1980 U.S. Census and Bureau of Economic Analysis.     

Poverty,Innovation Capacity,and State Economic Development in the Knowledge Economy: Evidence from the U.S.

We examine poverty's effect in two ways. First, we study the relationship between poverty and capacity for innovation in the U.S. states; second, we study the combined effects of poverty and innovation capacity on U.S. state economic output and employment. Because many of the relationships among poverty, innovation capacity and economic performance are simultaneous, we employ the Arellano Bond Difference GMM estimator to estimate various models using panel data (1980–1999). The findings reveal a negative indirect effect of socio‐economic need (poverty) on human and U.S. state and local financial innovation capacity, though there is no empirical link between poverty and federal financial capacity. We find no statistically significant evidence of the contemporaneous effect of poverty on state economic performance, holding innovation capacity constant. This suggests that poverty primarily affects state economic performance indirectly through reduction of innovation capacity. Overall, our findings suggest that U.S. officials ought to be concerned about the role poverty plays in diminishing their state economies' capacity to innovate.     

The breeding of the cultivated potato species solanum x juzepczukii and S. x curtilobum II. The resynthesis of S. x juzepczukii and S. x curtilobum

Summary The possibility of combining anew the genomes of wild and cultivated progenitors of triploid S. x juzepczukii and pentaploid S. x curtilobum by following the known evolutionary pathway of these species was investigated.The resynthesis of S. x juzepczukii was easy, and a wide range of synthetic forms was bred. Among these were forms with higher frost resistance (-5°C) than has been found in natural S. x juzepczukii. The total tuber glycoalkaloid content of several synthetic hybrids was lower than or as low as that of natural clones. Most synthetic hybrids were more vigorous than natural S. x juzepczukii and produced about the same types of tubers as are found in the natural range of variation. The best diploid parents were found in the species S. goniocalyx.The attempt to resynthesize pentaploid S. x curtilobum has not been successful but tetraploid plants were obtained in the process. An explanation for the occurrence of tetraploids resulting from triploid x tetraploid and/or diploid crosses is offered.The newly bred tetraploids contain at least one genome from S. acaule (possibly two) and hybridize easily with ssp. andigena. They thus provide a means for the transfer of S. acaule germ plasm into the tetraploid cultivated gene pool which would profit from the frost resistance of S. acaule.     

Income Migration and Income Convergence across U.S. States, 1995–2010

In this paper we examine how internal migration redistributes earned income across U.S. states between 1995 and 2010. We examine interregional income flows by first describing the movement of earned income between U.S. states. Second, we examine the effect of income migration on spatial patterns of income inequality. The question we ask is, “does migration increase or decrease convergence income across U.S. States?” A primary contribution of this paper is that instead of using only 1 year of income migration data to explore these issues, we use yearly data from the first year the Internal Revenue Service (IRS) data started including income (1995/1996) up to the most current data available (2009/2010). Results indicate that income convergence/divergence across states varies by whether or not there is general economic expansion or contraction. Nevertheless, some high‐amenity states continually attract high‐income households.     

Settlement,abundance, growth and mortality of juvenile flatfish in a subtropical tidal estuary (Georgia,U.S.A.)

The population dynamics of juveniles of some flatfish species were studied in the Duplin River, a tidal creek in a subtropical salt-marsh area in Georgia, U.S.A. from April until September 1990. Seven species were found. Paralichthys dentatus, Paralichthys lethostigma, Paralichthys oblongus and Trinectus maculatus were relatively rare. Etropus crossotus, Citharichthys spilopterus and Symphurus plagiusa were abundant and settled during the period studied. E. crossotus was the most abundant species with a mean abundance of 18 ind·10⁻² m⁻² (max. 287). Demersal settlement of E. crossotus took place in shallow areas and over sandy bottoms from mid-May to August. Prolonged settlement hampered the calculation of growth rate and instantaneous mortality rate. However, laboratory growth experiments indicated a mean growth of about 0.50 mm·d⁻¹ at 24–28°C. Juveniles of C. spilopterus were already present in the Duplin River in March. Settling continued until the end of April with a mean abundance of 3.5 ind·10⁻² m⁻² (max. 183). With increasing size the juveniles of this species tended to migrate to deeper waters and to the mouth of the river, possibly as a reaction to increasing water temperatures. Maximum growth rate was 1.4 mm·d⁻¹ at about 26°C. The mean instantaneous mortality rate (z) was estimated at 0.03·d⁻¹. Settling of S. plagiusa occurred from mid-May onwards. The mean abundance was 10.3 ind·10⁻² m⁻² (max. 98.3). Newly settled juveniles were most abundant on muddy sediments in the shallow river areas. The maximum growth rate was 1.3 mm·d⁻¹ at about 28°C. The mean instantaneous mortality rate (Z) decreased from 0.04·d⁻¹ in April to 0.01·d⁻¹ in August. At all sites the abundance of juveniles of this species decreased with increasing water depth. Predation experiments indicated that blue crabs (Callinectes similis and C. sapidus) and sea robins (Prionotus sp.) are potential predators on juvenile flatfish. The high abundances of juvenile flatfish indicate that the tidal creeks are an important nursery area. The correspondence between growth rates estimated from field data and those observed in the laboratory suggests that growth in the nursery is mainly related to water temperature and not food limited.     

Immigration and settlement pattern of Paralichthys dentatus and P. lethostigma in an estuarine nursery ground,North Carolina,U.S.A.

Immigration and settlement pattern of 0-group summer flounder (Paralichthys dentatus) and southern flounder (P. lethostigma) in an estuarine nursery are described. Flounders entering the estuary were transforming larvae. Despite their sympatric occurrence during larval immigration, the two species were found concentrated in different habitats. Sampling along transects within the estuary indicated that newly settled southern flounder were concentrated on tidal flats towards the head of the estuary while greatest numbers of summer flounder were captured on tidal flats in the middle reach of the system. Logistic regression analysis of presence/absence data indicated that salinity affected the distribution of southern flounder while substrate type was an important factor affecting the distribution of summer flounder. Numbers of both species on tidal flats declined in the spring, southern flounder appeared to move upstream to oligohaline riverine habitat and summer flounder appeared to move to high salinity salt marsh habitat. The segregated distribution apparent in juveniles is largely established during the immigration period. Differences in settling behaviour and subsequent movement and/or differential mortality occurring during settlement, appear important in determining the observed distribution of juvenile summer and southern flounder.