Southern Maryland Research Articles

An assessment of soil nitrogen testing considering the carry-over effect

In order to evaluate the economic and environmental consequences of soil nitrogen tests, this paper combines a dynamic fertilizer use decision model with a crop production model. The pre-side-dress soil N-test is evaluated for a hypothetical farmer growing corn at the ARS Sustainable Agriculture Demonstration Farm site in southern Maryland. For a farmer not currently using a soil N-test, adoption of this technology can lead to the enhancement of net farm income and the reduction in nitrogen loss to the environment. This will transpire only if the farmer is currently underestimating nitrogen carry-over by more than 25% or applying nitrogen fertilizer based solely on an expected plateau-yield goal.

Genetic linkage of the dentinogenesis imperfecta type III locus to chromosome 4q.

Dentinogenesis imperfecta type III (DGI-III) is an autosomal-dominant disorder of dentin formation which appears in a tri-racial southern Maryland population known as the "Brandywine isolate". This disease has suggestive evidence of linkage to the long arm of human chromosome 4 (LOD score of 2.0) in a family presenting with both juvenile periodontitis and DGI-III. The purpose of this study was to screen a family presenting with only DGI-III to determine if this locus was indeed on chromosome 4q. Furthermore, we wanted to determine if DGI-III co-localized with dentinogenesis imperfecta type II (DGI-II), which has been localized to 4q21-q23. Therefore, a large kindred from the Brandywine isolate was identified, oral examination performed, and blood samples collected from 21 family members. DNA from this family was genotyped with 6 highly polymorphic markers that span the DGI-II critical region of chromosome 4q. Analysis of the data yielded a maximum two-point LOD score of 4.87 with a marker for the dentin matrix protein 1 (DMP1) locus, a gene contained in the critical region for DGI-II. Our results demonstrated that the DGI-III locus is on human chromosome 4q21 within a 6.6 cM region that overlaps the DGI-II critical region. These results are consistent with the hypothesis that DGI-II is either an allelic variant of DGI-III or the result of mutations in two tightly linked genes.

An Evaluation of Soil Nitrogen Testing Considering the Carry-Over Effect

ABSTRACT In order to evaluate the economic and environmental consequences of soil nitrogen tests, this paper combines a dynamic fertilizer use decision model with a crop production model. The preside-dress soil N-test is evaluated for a hypothetical farmer growing corn at the ARS Sustainable Agriculture Demonstration Farm site in southern Maryland. For a farmer not currently using a soil N-test, adoption of this technology can lead to the enhancement of net farm income and the reduction in nitrogen loss to the environment. This will transpire only if the farmer is currently underestimating nitrogen carry-over by more than 25 percent or applying nitrogen fertilizer based solely on an expected plateau-yield goal.

Wealth and Welfare in Early Maryland: Evidence from St. Mary's County

S T. Mary's was Maryland's first county. Located on a peninsula bounded by the Chesapeake Bay on the south, the Patuxent River on the east, and the Potomac River and one of its tributaries on the west, the county became part of what today is loosely called southern Maryland, a region that also includes Charles and Calvert and the southern parts of Prince George's and Anne Arundel Counties (see Figure I). Along both rivers and the bay, water resources are abundant. However, following the water-in the language of present-day Maryland fishermen-was not an occupation in colonial St. Mary's. There, men sought their fortunes in tobacco, specifically oronoco leaf, for which the soils of the region are exceptionally well suited. In some parts of the Chesapeake, eighteenth-century planters diversified into other export crops, but St. Mary's County planters were slow to follow.' St. Mary's was a tobacco county. This article analyzes economic performance in St. Mary's over the colonial period. A remarkable set of probate inventories provides a foundation upon which to construct estimates of mean, per head, and per household wealth for decedents and those who lived in the households of decedents. A small cluster of these records survive for the years around i640, and a nearly continuous series begins in i658. Unfortunately, inventories report only the movable wealth of some recently deceased propertyowners, not the wealthor, better yet, the incomes-of the living population. Nevertheless, these records do enumerate the belongings of decedents in exquisite detail, listing and valuing all possessions except real estate. Consequently, inventories are the best available source for studying colonial wealth in personalty. With some manipulation, they can be used to estimate changes in the accumulation and distribution of wealth in this form among the living as well as the dead. (For convenience, wealth in movables will be referred to hereafter as personal wealth.) This use of inventories, in combination with information

Serologic evidence of a natural infection of white-tailed deer with the agent of human granulocytic ehrlichiosis in Wisconsin and Maryland.

White-tailed deer participate in the maintenance of the Ixodes tick life cycle and are reservoirs for some tick-borne infectious agents. Deer may be useful sentinels for tick-transmitted agents, such as ehrlichiae. In order to determine whether white-tailed deer are markers of natural transmission or are reservoirs for the human granulocytic ehrlichiosis (HGE) agent, we performed indirect immunofluorescent-antibody (IFA) tests and immunoblotting with the HGE agent and Ehrlichia chaffeensis on sera from 43 and 294 deer captured in northwest Wisconsin during 1994 and 1995, respectively, and 12 deer from southern Maryland. According to IFA testing, 47% of 1994 Wisconsin sera, 60% of 1995 Wisconsin sera, and 25% of Maryland sera contained HGE agent antibodies. All IFA-positive deer sera tested reacted with the 44-kDa band which is unique to the Ehrlichia phagocytophila group. Serologic reactions to E. chaffeensis were detected by IFA testing in 15 of 337 (4%) Wisconsin deer and in 10 of 12 (83%) Maryland deer, while 60 and 80% of E. chaffeensis IFA-positive Wisconsin and Maryland deer sera, respectively, reacted with the E. chaffeensis 28- to 29-kDa antigens by immunoblotting. A total of 4% of deer from Wisconsin and 25% of deer from Maryland were found by IFA testing to have antibodies to both the HGE agent and E. chaffeensis; 75% of these were confirmed to contain E. chaffeensis antibodies by immunoblotting. These results suggest that white-tailed deer in diverse geographical regions of the United States are naturally infected with the HGE agent, E. chaffeensis, or both and that these animals, and potentially humans, are exposed to infected ticks at a high frequency in nature.

The impact of the nitrogen carryover effect on economic activity and the environment

The economic and environmental consequences of soil nitrogen tests can have significant impacts on agricultural production. Some of these are explored here. The pre-side-dress soil N-test is evaluated for a hypothetical farmer growing corn at the ARS Sustainable Agriculture Demonstration Farm site in southern Maryland. For a farmer not currently using a soil N-test, adoption of this technology can lead to the enhancement of net farm income and the reduction in nitrogen loss to the environment. This will transpire only if the farmer is currently underestimating nitrogen carryover by more than 25% or applying nitrogen fertilizer based solely on an expected plateau-yield goal.

Vietnamese in America: Literary Representations

When, in 1987, John Clark Pratt proposed a structure to the canon of Vietnam War literature in his excellent Bibliographic Commentary, he divided the material-fictional treatments-into five (corresponding to stages in the battlefield progress of the war itself) that the literature, regardless of publication date, represented. acts in Pratt's Shakespearean tragedy are surrounded by a prologue and an epilogue (everything after 1975). A mere ten years ago, then, Vietnam War literature was primarily defined as combat literature. However, a year after Pratt's essay appeared, William J. Searle, in his Search and Clear, provided a selection of commentary that recognized an important second stage of Vietnam War literature. In a section on Return and Partial Recovery, essays by James A. Robinson, Vince Gotera, and Searle himself provide an early map of the war's consequences in terms of representations of the veteran's return. Such representations (like Larry Heinemann's prizewinning Paco's Story and Philip Caputo's Indian Country) explore not only the veteran's condition but also the represented America the veteran re-entered. Many of these titles have a temporal sweep that overlaps the chronology of the war itself. In his study of veterans' poetry (Radical Visions, 1994), Gotera collapses the literature into two neat categories, The `Nam' and The World. Works in the former group reflect primarily battlefield experience, while those in the latter group-a group having grown in size and importance-portray the returned veterans' ongoing trauma, problems of reintegration into U.S. society, and (less often) the more general theme of Vietnam as a continuing cultural pathology or syndrome.' If extended in fiction, the latter category would include such works as Bobbie Ann Mason's In Country and an expanding library of detective fictions featuring protagonists whose Vietnam War backgrounds influence the conduct of their cases and their lives.2 Another group of writings, perhaps distinctive enough to constitute a separate category, is beginning to claim attention: representations of the Vietnamese in America. One consequence of the war is the growing number of stateside Vietnamese communities. These communities are directly investigated in several monographs and in a special issue of Vietnam Generation entitled Southeast Asian-American Communities (1990) that contains a comprehensive bibliography. imaginative literature, particularly prose fiction, reflecting this new ingredient in our cultural landscape explores or at least hints at the meaning of this presence both to its members and to the majority culture. While there is a growing body of literature by Vietnamese Americans, representations of the Vietnamese in America by writers from the majority culture reveal something about that culture's ability to perceive and to absorb this new element. Significant among literary treatments of these Vietnamese residents are Robert Olen Butler's novel Deuce (1989) and his short story collection A Good Scent from a Strange Mountain (1992). Other noteworthy representations include Wayne Karlin's Lost Armies (1989), which conjures up a Vietnamese community in southern Maryland proximate to the nation's capital, and Charlie McDade's Gulf (1986), in which Vietnamese refugees try to take up their traditional occupation of shrimp fishing in coastal Texas. T. Jefferson Parker's mystery thriller, Little Saigon (1988) examines the turbulent Southeast Asian community in Orange County, California. Four of these five works have as background or foreground a love relationship between an American man who served in Vietnam and a Vietnamese woman he met there, a circumstance that suggests a tentative embrace of cultures and a healing potential even as it harkens back to a longer tradition of wartime romances about American GI's who had affairs with and sometimes married Asian women.3 Renny Christopher's recent book, Viet Nam War / American War (1995) elaborates the larger context for these concerns. …

Mineralogy and Aeroradioactivity as Indicators of Radon Hazard Zones

The concentrations of indoor radon in the basements of homes located in southern Maryland average 1.3 times the first-floor radon concentrations. Particular geological units tend to be associated with higher indoor radon. In the study area, homes underlain by phyllite are generally above 4 pCi / L (the U.S. Environmental Protection Agency “action level”). Comparative studies between indoor radon and total-gamma aeroradioactivity show that aeroradioactivity can be accurately used to estimate community radon hazards. When combined, geology and aeroradioactivity can be used to identify problem homes.

The Catholic Encounter with Race

The Catholic Encounter with Race Jay P. Dolan (bio) John T. McGreevy. Parish Boundaries: The Catholic Encounter with Race in the Twentieth-Century Urban North. Chicago: University of Chicago Press, 1996. vi + 362 pp. Illustrations, notes, and index. $27.50. David W. Southern. John LaFarge and the Limits of Catholic Interracialism, 1911–1963. Baton Rouge: Louisiana State University Press, 1996. xxii + 420 pp. Illustrations, notes, and index. $45.00. The vast majority of European immigrants arrived in this country with a strong sense of ethnic identity; but the idea of race and color, of white versus black, was not yet a part of their world. They were Irish or German, Polish or Italian, and visibly proud of their heritage. They established ethnic villages in the midst of urban America that were reminiscent of the Old World, and developed a spirit of nationalism associated with the land of their birth that was hardly visible when they had lived in their countries of origin. Not long after their arrival in the United States these immigrants also adopted an identity as white Americans. Recent studies have highlighted how immigrant groups, the Irish in particular, became white. 1 In becoming white many immigrants adopted the racist attitudes of the white American majority, and bitter antipathies developed between some of these white ethnic groups and the black American community. Large numbers of these European immigrants were Catholics. They belonged to a church that preached a gospel of universalism and claimed as its members people of all cultures and colors. Yet, during the course of the nineteenth century, clerical leaders in the Catholic church in the United States, like the people in the pew, adopted the racist attitudes of the white American majority. As a result American Catholicism became a Jim Crow church. Well into the twentieth century, its parishes, schools, colleges, seminaries, and religious orders of priests and nuns remained racially segregated. By the 1960s, however, many Catholic clergy and laity were in the vanguard of the civil rights movement and stood side by side with Martin Luther King, Jr. and his associates as they marched in Selma and Chicago; the Catholic church was no longer a racially segregated institution. [End Page 282] Two very different studies, the books of David W. Southern and John T. McGreevy seek to explain how this change took place. Southern’s biographical study of John LaFarge, S.J. (1880–1963) examines his work in race relations. McGreevy focuses on American Catholics, examining “the threads connecting religion, race, and community in the nation’s northern cities” in the twentieth century (p. 3). Because African Americans never comprised more than 2 percent of the Catholic population, there was not much interest in their history among professional historians. This has changed in the past twenty-five years as more historians have sought to uncover a rich history that began in the colonial era of slavery. In 1990, for example, Cyprian Davis, an African-American Benedictine monk, wrote the first comprehensive history of African-American Catholics, incorporating much of the recent research into his study. 2 The works of Southern and McGreevy will not only enrich our understanding of race relations in the Catholic community, but will also help readers to appreciate more fully the role of religion in the history of race relations in twentieth-century America. John LaFarge was a pioneer in the history of race relations in the United States. The son of a famous artist, he was born into an aristocratic milieu in Newport, Rhode Island. After graduating from Harvard, he decided to become a priest and entered the religious order known as the Jesuits. In 1911 his superiors sent him to do pastoral work in the black Catholic community in southern Maryland. After fifteen years there, he moved to New York City (where he remained until his death in 1963) and began a distinguished career as a writer and editor of the influential Jesuit journal, America. LaFarge was an intellectual who used his position at America as a pulpit to preach on behalf of racial justice. Grounding his interracial philosophy in the Catholic social gospel tradition, he believed that blacks had the same natural rights as whites and...

Radon reduction in homes constructed on saprolite in the Central Appalachians

A 3-year study of indoor radon in more than 1000 homes in northern Virginia and southern Maryland was conducted using 3-month exposure alpha-track monitors. In a study set of 200 homes, first-floor indoor radon concentrations, which most closely approximates home exposure levels, averaged slightly more than 3 pCi/l. In a study set of 100 homes, sub-slab ventilation was used to reduce indoor radon concentrations. Interest in remediation was related to public perception of the hazardous nature of radon; people living in homes with indoor radon measurements of more than 4 pCi/l were more likely to participate in the remediation phase of the project. Sub-slab ventilation was successful in more than 90% of the homes in reducing indoor radon from concentrations as high as 30 pCi/ to less than 4 pCi/l, at least for the entire year of post-remediation radon measurements.

John LaFarge and the Limits of Catholic Interracialism, 1911-1963 by David W. Southern

BOOK REVIEWS525 understood as various manifestations of his ecumenical dream. Christensen states that Briggs beUeved "that free inquiry, comparative historical research, and honest debate would bring about a synthesis of beUef and practice out of the variety of expressions of the faith. Historical critical study . . . would bring consensus, and differences between church bodies would eventuaUy be reconcUed in a comprehensiveness (one of Briggs's favorite words) which aUowed for a variety of temperaments." Of particular interest to CathoUc biblical scholars and historians of Modernism, Christensen documents Briggs's central role (Ln league with Baron von Hügel) in attempting to deflect the fuU brunt of the papal condemnation of critical biblical and historical scholarship in Pascendi and Lamentabili. Christensen offers students of the modern ecumenical movement, as weU as students of GUded Age reUgion, a smart new "read" on one of the most famous figures of the era. Christensen deftly makes comprehensible one of the most complex scholars in the history ofAmerican reUgion. Mark S. Massa, SJ. Fordham University John LaFarge and the Limits ofCatholiclnterracialism, 1911-1963- By David W Southern. (Baton Rouge: Louisiana State University Press. 1996. Pp. xxüi, 385. $45.00.) As Professor David Southern mentions in his preface, Father John LaFarge, SJ., came to his attention while Southern was doing research on the influence of Gunnar Myrdal'sAn American Dilemma.Additional research on LaFarge left Southern wondering why no scholarly book had been written on this pioneer Catholic interracialist. Given Southern's interest in race issues, he hopes this work wiU help in the larger effort to move CathoUc history from the margins of American history and integrate it with American history. This thoroughly researched book succeeds both in analyzing LaFarge's successes and faUures and in comparing LaFarge's interracial work to the larger civU rights movement. The first three chapters estabUsh the context for understanding this son of the famous nineteenth-century artist. Professor Southern argues that from the aristocratic famUy background, the Jesuit formation and education, and the prevaUing racial attitudes of church and society what emerged was a priest who could be described as paternalistic, conservative, defensive, overly prudent, cautious , and ambivalent aboutAfrican-American culture. From this combination of experiences,John LaFarge developed a gradual, long-term approach to racial issues . The next five chapters cover the period from LaFarge's joining the staff of America in 1926 until 1941.The important issues discussed are: interraciaUsm versus black protest, LaFarge's relationship with Victor and Constance Daniel, 526BOOK REVIEWS the estabUshment of the CathoUc Interracial Council of New York and the interracial movement, and LaFarge's opposition to communism, fascism, and racism.Two cases which receive great attention are LaFarge's relationship with the Federated Colored Catholics (FCC) and the closing of the Cardinal Gibbons Institute in southern Maryland. Professor Southern argues that John LaFarge steered the FCC away from the mission of its founder, Dr.ThomasWyattTurner, as a CathoUc African-American protest organization toward the less confrontational interracial approach. The closing of the Cardinal Gibbons Institute involved a protracted battle with the principal and assistant principal of the school,Victor and Constance Daniel. From these two cases, LaFarge's reputation emerges battered and stained. In the remaining biographical chapters, Professor Southern examines LaFarge 's and the Catholic interracial movement's responses to the race question through the "hot" and "cold" wars, the civü rights movement in the pre- and post-Brown decision era, and the final years ofJohn LaFarge's Ufe.The final two chapters of the book provide a summary about John LaFarge's interracial work within American CathoUcism and a postscript on black CathoUcism. Professor Southern has written a very interesting and intriguing book which examines not only the life of a pioneer Catholic interraciaUst but also examines in a thorough manner the CathoUc efforts to address the American dUemnia. He poses some very provocative questions and offers historical interpretations which deserve further discussion and study. His concluding Unes Ui the summation of LaFarge jump off the page: "StUl, for roughly three decades LaFarge was the primary spokesman for the American CathoUc church on black-white relations.This fact alone speaks volumes about the church's past record in...

April 15, 1865

April 15, 1865 William A. Tidwell On April 15, 1865, nearly a week after the surrender of the Army of Northern Virginia, Confederate and Union cavalry had a skirmish in St. Mary's County, Maryland. The skirmish occurred the day after John Wilkes Booth shot President Lincoln, and it has been largely ignored—obscured by a dispute between two Union officers and overwhelmed by the many activities concerned with the pursuit of the assassins. Yet this skirmish played an important part in the way in which the pursuit unfolded and may help to explain some of the actions of Booth and the individuals who assisted him in his escape. While it provides no certain answer to the role played by Dr. Samuel Alexander Mudd, it adds one more possible item to those linking Dr. Mudd and Booth in a common enterprise. According to the U.S. Naval Observatory in Washington, D.C, April 15, 1865, was a cloudy day with rain beginning at 7:30 a.m., shortly after the death of Abraham Lincoln. The technician recording the weather added a note at the bottom of the page: "the building was draped in mourning for the death of the President of the United States." At the end ofthe day he recorded the minimum and maximum temperatures as 47° and 67° Fahrenheit. The Nautical Almanac shows that at that date and latitude the sun rises shortly after 5:30 a.m. and sets at about 6:30 p.m. It was a cold, wet day, but the weather was not bad enough to prevent movement.' John Wilkes Booth, who thought of himself as an American Brutus, and his companion, David Herold, had reached the home of Dr. Mudd in southern Maryland about four o'clock in the early hours of April 15th, before the rain began. Dr. Mudd lived four miles north of Bryantown in Charles County, Maryland, on a peninsula of roughly thirty by one hundred miles, bounded by the Potomac and Patuxent Rivers. This peninsula included the southern part of Prince George's County and all of Charles and St. Mary's Counties.2 1 Photostat copy oflocal weather observations for April 1 865, U.S. Naval Observatory, Washington . D.C. 2 Statements of Dr. Samuel A. Mudd, Apr. 21, 1865, M-599, reel 5, frames 0212-25, 0226-39, Civil War History, Vol. xlii. No. 3 © 1996 by The Kent State University Press APRIL 15, I865 221 -Si Surratt's Tavern Beantown Bryantown Canter) (Swart) Government Farms ,,*.,„; Charlotte Hall -¦ Aliens Fresh ftChaptico Leonarotown SOUTHERN MARYLAND 1865 - Towns/homes ?/. Government farms --. Probabte area of skirmish — Roads Streams Southern Maryland, 1 865 In spite of its proximity to Washington, this southern Maryland peninsula was largely isolated from the contemporary world. It held many tobacco farms and produced some corn, wheat, and vegetables. There were a few small villages and isolated country stores, but on the whole the area was sparsely populated and heavily forested. There were no railroads or major turnpikes. Several estuaries of the Potomac cut deeply into the southern coast, and the Wicomico River, the largest of the estuaries, was fed by streams that flowed through two long, narrow swamps that formed obstacles to ground travel. These National Archives; Jack D. Brown et al., Charles County, Maryland (Charles County Bicentennial Committee, 1976). 222CIVIL WAR HISTORY were Zekiah Swamp, about twelve miles long, which passed Dr. Mudd's residence and reached its upper end a short distance away, and Gilbert's Swamp, shorter than Zekiah Swamp but nonetheless a substantial barrier for several miles.3 The people of southern Maryland were strongly anti-Union and provided substantial numbers ofsoldiers to the Confederate army. In addition, the remoteness of the area provided many opportunities for exploitation as a route for the smuggling of items needed in the Confederacy and for the movement of secret agents. The Union also exploited the remoteness of the area by establishing the Hammond Hospital for convalescing Union wounded and Camp Hoffman, one of its major prisons for captured Confederates, at Point Lookout, the extreme terminus ofthe peninsula where the Potomacjoins Chesapeake Bay. There were also small Union facilities in the area; a supply depot at...

Waterborne radon pollution of indoor air

The domestic use of radioactive water has long been a cause for concern, but only a few studies have examined prolonged exposure to radionuclide concentrations found in natural settings. This paper reports on the indoor radon concentrations from 1,500 homes in northern Virginia and southern Maryland and well water radon from 700 homes in the same area. Indoor radon concentrations are almost all between 1 and about 40 pCi/L. The winter season shows the highest values with about 40% of the homes over the EPA action level of 4.0 pCi/L. The summer season shows the lowest values with about 25% of the homes over this level. This seasonal variation is related to home ventilation. Waterborne radon in homes with private wells ranges from about 100 pCi/L to about 8,000 pCi/L. In small homes, indoor radon can be significantly increased by outgassing of the home water supply, even at water radon levels of less than 10,000 pCi/L.

Aquia Aquifer Dissolved Cl− and 36Cl/Cl: Implications for Flow Velocities

The Aquia aquifer (southern Maryland) contains a remarkably smooth Cl− profile (0.46–3.23 ppm) along its flow path. This is interpreted as a record of historic changes in the deposition of Cl− in this region. Those changes have been influenced by the rise and fall of sea level, which has altered the distance of the recharge region from the coastline by ∼200 km. The 36Cl concentration along the flow path is not as smooth as the Cl− profile. Historic variations in cosmogenic production, atmospheric transport, precipitation, and evapotranspiration all might have influenced 36Cl concentrations. A general similarity between the 36Cl and Cl− profiles suggests that changes in precipitation and evapotranspiration rates, which influence both tracers similarly, are particularly important. To reconcile 14C, 36Cl, and hydrologic data, we propose a two‐tier model for flow in the Aquia. Shallower portions of the aquifer (<60 m) were subjected to hydraulic gradients and flow rates approximately 5 times larger during the Pleistocene than modern, prepumping rates. At greater depths, flow rates were much slower and less variable; water in this region may be old enough to record some 36Cl decay.

Modern chlorine-36 deposition in southern Maryland, U.S.A.

Monthly wet precipitation samples were collected at the Elms Environmental Education Center in St. Mary's County in southern Maryland from February 1991 to January 1993 and analyzed for 36Cl. The analyses indicate that 36Cl wet deposition undergoes seasonal variations, reaching a maximum in March/April. This pattern is well established for other stratospheric tracers such as Pu, 7,10Be and ozone, and reflects seasonal variations in stratospheric-tropospheric mixing. The mean wet deposition 36Cl flux was 3.86 ± 0.54 (× 10 −3) atoms/cm 2s. Bulk precipitation samples were also collected at the site during the sampling period, and these data are compared to the wet-only data. The mean bulk deposition flux was 5.85 ± 0.78 (× 10 −3) atoms/cm 2s. Dry deposition accounts for approximately 25% of the total 36Cl deposition. Data from this study are compared with groundwater 36Cl data from the Aquia Aquifer in southern Maryland, and it is concluded that modern deposition does not account for the relatively high 36Cl concentrations found in the Aquia.

Survey of molybdenum fertility status in Maryland coastal plain soils for tobacco production

Abstract Coastal Plain soils in southern Maryland are typically acid (pH = 5.0±0.5) with low organic matter (1.2±0.5%), clay (2.8 to 9.8%), CEC (2.4 to 6.8 meq 100/g), and total Fe contents (4.5 to 34.9 g/kg). The objectives of this investigation were to assess the status of plant available molybdenum (Mo) in these soils by examining the extractable Mo levels in Ap horizon soil samples and tissue Mo contents in cured tobacco collected across a five‐county region. Seventy soil samples representing 11 soil series and 198 composite samples of tobacco served as the basis for the surveys. Plant available Mo in soil, estimated using a solution containing 0.18M ammonium oxalate and 0.1M oxalic acid as the extractant, ranged from 0.02 to 0.53 (ig/g and averaged 0.08 μg/g Mo. Three of the 11 soil series examined and 30% of the total soil samples exhibited extractable Mo levels ≤ 0.03 μg/g therefore may have less than adequate available Mo for tobacco. Cured leaf Mo contents ranged from non‐detectable to 7.95 μg/g ...

Stratigraphy, petrography, and correlation of late Cenozoic middle Atlantic Coastal Plain deposits: Implications for late-stage passive-margin geologic evolution

Regional chronostratigraphic correlation of middle Atlantic upper Coastal Plain and Fall Zone fluvial deposits, long thought to represent the updip, proximal facies of a well-dated, post-Oligocene marine sequence in the Salisbury Embayment, remains incomplete, in part, because of the paucity of biostratigraphic data. Petrography-based lithostratigraphic correlations provide an opportunity to extend age control present in downdip marine deposits, updip to fluvial deposits, thus establishing the means for a regional chronostratigraphic correlation. Previous stratigraphic studies in New Jersey, Delmarva, southern Maryland, Virginia, and the central Appalachian Piedmont are linked by a crucial sequence of fluvial deposits at the head of Chesapeake Bay. Here petrography-based lithostratigraphic correlations demonstrate (1) late Oligocene-late Miocene, Susquehanna River-dominated, polygenetic, quartzose fluvial aggradation (Bryn Mawr Formation); (2) Pliocene, heterolithic, but quartz-dominated fluvial-terrace and alluvial-fan deposition (Perryville formation); (3) Pliocene-early Pleistocene, paleo-Delaware-Hudson River- dominated, lithic- and feldspathic-rich, fluvial aggradation (Pensauken Formation); and (4) the initiation of estuarine conditions (Turkey Point beds) by early Pleistocene time. These results are synthesized to propose a new late Cenozoic regional chronostratigraphic correlation and depositional history for the Salisbury Embayment. The correlation elucidates a complex interaction between passive margin isostasy, tectonics, eustasy, and sediment source.

The reliability of geophysical surveys at historic-period cemeteries: An example from the plains cemetery, mechanicsville, Maryland

Remote-sensing techniques have considerable potential for examining the structure of the archaeological record with minimum disturbance. This article examines two techniques, ground-penetrating radar and proton magnetometer surveys, which were used at a historic-period cemetery in southern Maryland. The reliability of these two techniques is assessed against the results of subsequent archaeological testing. Findings from this assessment are then used to suggest refinements in the interpretation of future surveys.

An artificial neural network approach for evaluating transportation network improvements

AbstractAs demand increases over time, new links or improvements in existing links may be considered for increasing a network's capacity. The selection and timing of improvement projects is an especially challenging problem when the benefits or costs of those projects are interdependent. Most existing models neglect the interdependence of projects and their impacts during intermediate periods of a planning horizon, thus failing to identify the optimal improvement program. A multiperiod network design model is proposed to select the best combination of improvement projects and schedules. This model requires the evaluation of numerous network improvement alternatives in several time periods. To facilitate efficient solution methods for the network design model, an artificial neural network approach is proposed for estimating total travel times corresponding to various project selection and scheduling decisions. Efficient procedures for preparing an appropriate training data set and an artificial neural network for this application are discussed. The Calvert County highway system in southern Maryland is used to illustrate these procedures and the resulting performance.

AN EVALUATION OF A WIDE RANGE OF JOB-GENERATING ACTIVITIES FOR RURAL COUNTIES

The job-generating activities of governments and civic groups in fifteen rural counties on the Delmarva Peninsula and southern Maryland are examined through more than 175 informant interviews and field work. These counties engaged in a wide range of job-generating activities and many of these were directed toward business recruitment. When community leaders ranked activities for their impacts on jobs, industrial parks received the most high ranks, economic development units second and tourism promotion third. Special financial arrangements for relocating or new businesses were evaluated as very important on average to economic development and grantsmanship was a successful activity in all counties though it never ranked as the first or second most productive job-generating activity. Guidance on economic development strategies for rural counties are derived from the findings.