bluuebunny/crossref_metadata_2025 huggingface dataset:
Analyzing longitudinal data with patients in different disease states during follow‐up and death as final state
Authors: le Cessie Saskia , de Vries Elisabeth G. E. , Buijs Ciska , Post Wendy J.
Published: October 2009

This paper considers the analysis of longitudinal data complicated by the fact that during follow‐up patients can be in different disease states, such as remission, relapse or death. If both the response of interest (for example, quality of life (QOL)) and the amount of missing data depend on this disease state, ignoring the disease state will yield biased means. Death as the final state is an additional complication because no measurements after death are taken and often the outcome of interest is undefined after death.

We discuss a new approach to model these types of data. In our approach the probability to be in each of the different disease states over time is estimated using multi‐state models. In each different disease state, the conditional mean given the disease state is modeled directly. Generalized estimation equations are used to estimate the parameters of the conditional means, with inverse probability weights to account for unobserved responses.

This approach shows the effect of the disease state on the longitudinal response. Furthermore, it yields estimates of the overall mean response over time, either conditionally on being alive or after imputing predefined values for the response after death. Graphical methods to visualize the joint distribution of disease state and response are discussed.

As an example, the analysis of a Dutch randomized clinical trial for breast cancer is considered. In this study, the long‐term impact on the QOL for two different chemotherapy schedules was studied with three disease states: alive without relapse, alive after relapse and death. Copyright © 2009 John Wiley & Sons, Ltd.
Polymer Adhesion at the Solid–Liquid Interface Probed by a Single–Molecule Force Sensor
Authors: Geisler Michael , Balzer Bizan N. , Hugel Thorsten
Published: October 2009

A method based on atomic force microscopy is used to delineate the properties that determine single‐molecule adhesion onto solid substrates in aqueous environment. Hydrophobicity as well as electrical properties of the substrate and the polymer are varied. In addition, the influence of the solvent composition, in particular the effect of ions, on the molecular adhesion at the solid–liquid interface is studied. Surprisingly, the polymer and surface‐related properties account for only small changes in adhesion force, while dissolved ions show a much larger effect. These results point towards the energy of solvation as the most important contribution to adhesion for a wide variety of polymers and substrate materials.
A Nanoelectronic Enzyme‐Linked Immunosorbent Assay for Detection of Proteins in Physiological Solutions
Authors: Stern Eric , Vacic Aleksandar , Li Chao , Ishikawa Fumiaki N. , Zhou Chongwu , Reed Mark A. , Fahmy Tarek M.
Published: October 2009

Semiconducting nanowires are promising ultrasensitive, label‐free sensors for small molecules, DNA, proteins, and cellular function. Nanowire field‐effect transistors (FETs) function by sensing the charge of a bound molecule. However, solutions of physiological ionic strength compromise the detection of specific binding events due to ionic (Debye) screening. A general solution to this limitation with the development of a hybrid nanoelectronic enzyme‐linked immunosorbent assay (ne‐ELISA) that combines the power of enzymatic conversion of a bound substrate with electronic detection is demonstrated. This novel configuration produces a local enzyme‐mediated pH change proportional to the bound ligand concentration. It is shown that nanowire FETs configured as pH sensors can be used for the quantitative detection of interleukin‐2 in physiologically buffered solution at concentrations as low as 1.6 pg mL−1. By successfully bypassing the Debye screening inherent in physiological fluids, the ne‐ELISA promises wide applicability for ligand detection in a range of relevant solutions.
A biting‐down approach to hierarchical decomposition of object‐oriented systems based on structure analysis
Authors: Zhang Lu , Luo Jing , Li He , Sun Jiasu , Mei Hong
Published: October 2009

System decomposition has been widely viewed as an effective means to facilitate the comprehension of complex software systems and/or capture potentially reusable components in them. In fact, various approaches to system decomposition have been intensively documented in the literature. However, during the process of system decomposition, only a few of them can also capture the target system's hierarchical organization structure, which is essential when the target system is very complex. In this paper, we present a biting‐down approach to hierarchical decomposition of object‐oriented systems. Compared with the previous hierarchical approaches, the distinct features of this approach are as follows. First, our approach does not rely on agglomeration, and thus can avoid some unnecessary calculations. Second, our approach does not require merging nodes when performing high‐level decomposition, and thus can avoid imprecision induced by the merging. To evaluate our approach, we conducted a case study and an experimental study on our approach. The results of these studies can confirm its effectiveness and its superiority over our previous approach. Copyright © 2009 John Wiley & Sons, Ltd.
Case study of a 40‐storey buckling‐restrained braced frame building located in Los Angeles
Authors: Dutta Anindya , Hamburger Ronald O.
Published: October 2009

Simpson Gumpertz & Heger has prepared two prototypical designs for a 40‐storey buckling‐restrained braced steel‐framed office building located at a generic site in Los Angeles, CA. One of these designs conforms in all respects, except height limits with the design criteria contained in the 2007 California Building Code and ASCE 7.05 Standard for Minimum Design Loads for Buildings and Other Structures. The second design has been conducted using a performance‐based approach generally based on the criteria contained in guidelines published by the Los Angeles Tall Buildings Council. The performance‐based design incorporates fewer bays of bracing and lighter members than the code‐based design, but is intended to provide performance at least equivalent to that anticipated for code‐designed buildings. The purpose of this work was to permit study of the performance capability of buildings designed to alternative criteria. This work was performed in support and under funding provided by the Pacific Earthquake Engineering Research Center's Tall Buildings Initiative. Copyright © 2009 John Wiley & Sons, Ltd.
Divide‐ and conquer‐based surveillance framework using robots, sensor nodes, and RFID tags
Authors: Xiao Yang , Zhang Yanping
Published: October 2009

Sensor networks are adopted in many surveillance applications. A traditional method for such applications is to deploy sensor nodes all over the surveillance region in order to cover as much area as possible. However, this way not only waste huge amounts of money for sensor nodes and resources, but it is also unnecessary and unrealistic sometimes. It provides huge amounts of garbage in the form of dead sensor nodes and batteries. It invokes many data collisions and places a serious burden on network protocols. In many applications, we have no need to have detail on every point inside the area, but only in some critical places. For example, in a forest fire surveillance application, covering the whole forest is unnecessary and unrealistic. In this paper, we propose a divide‐ and conquer‐based surveillance framework, in which a large surveillance area is divided into small areas by critical points and critical lines. Sensor nodes, sinks, robots, and RFID tags are all used. We only deploy sensor nodes along critical lines instead of all over the region. Our aim is to do surveillance with efficient deployment of sensor nodes and sinks, and to detect, track, and even capture targets, e.g., an intrusion tank or forest fire, with the collaboration of robots and sensor nodes. We study boundary coverage along critical lines. Robots perform tasks of patrolling, handling incidents, communicating with sensor nodes/sinks, and even being capable of deploying/throwing‐out sensor nodes/RFID tags. Finally, we evaluate perimeter coverage, robot patrol routing, and so on. Copyright © 2009 John Wiley & Sons, Ltd.
SCLDGM coded modulation for MIMO systems with spatial multiplexing and space‐time block codes
Authors: González‐López Miguel , Vázquez‐Araújo Francisco J. , Castedo Luis , Garcia‐Frias Javier
Published: October 2009

We analyze Multiple‐Input Multiple‐Output (MIMO) coded modulation systems where either Bit‐Interleaved Coded Modulation (BICM) with spatial multiplexing or concatenation of channel coding and Space‐Time Block Codes (STBCs) is used at transmission, assuming iterative Turbo‐like decoding at reception. We optimize Serially‐Concatenated Low‐Density Generator Matrix (SCLDGM) codes (a subclass of LDPC codes) for each system configuration, with the goal of assessing its ability to approach the capacity limits in either ergodic or quasi‐static channels. Our focus is on three relevant STBCs: the Orthogonal Space‐Time Block Codes (OSTBCs) for two transmit antennas (i.e., the Alamouti code), which enables optimum detection with low complexity; the Golden code, which provides a capacity increase with respect to the input constellation; and Linear Dispersion (LD) codes, which enable practical detection in asymmetrical antenna configurations (i.e., more transmit than receive antennas) for cases in which optimum detection is infeasible. We conclude that BICM without concatenation with STBCs is in general the best option, except for Alamouti‐coded 2×1 and Golden‐coded 2×2 MIMO systems. Copyright © 2009 John Wiley & Sons, Ltd.
Phosphoproteomics
Authors: Ozlu Nurhan , Akten Bikem , Timm Wiebke , Haseley Nathan , Steen Hanno , Steen Judith A.J.
Published: October 2009

Current analytical protein methods show phosphorylation to be the most ubiquitous, evolutionary conserved post‐translational modification Post‐Translational Modification (PTM). The reversible and transient nature of protein phosphorylation allows signal transduction pathways to carry out diverse cellular functions. From bacteria to humans, phosphorylation serves to modify protein function by altering protein stability, cellular location, substrate affinity, complex formation, and activity; thus allowing essential events such as cell cycle and growth to occur at precise times and locations. Phosphorylation controls a variety of events at many biological levels including: housekeeping activities controlled by single cells such as DNA transcription, cell‐cycle regulation, and energy metabolism; and cellular processes that involve signaling between cells or the environment including such as neuronal migration and immune system recognition. This review summarizes state‐of‐the‐art proteomics technologies available to study phosphorylation in biological systems. We highlight the tremendous steps the field has made in the last 5 years which allow quantitative global analyses while pointing out caveats in experimentation. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Biological Mechanisms > Cell Signaling
A game-theoretic framework for specification and verification of cryptographic protocols
Authors: Saleh Mohamed , Debbabi Mourad
Published: October 2009

We model security protocols as games using concepts of game semantics. Using this model we ascribe semantics to protocols written in the standard simple arrow notation. According to the semantics, a protocol is interpreted as a set of strategies over a game tree that represents the type of the protocol. The model uses abstract computation functions and message frames in order to model internal computations and knowledge of agents and the intruder. Moreover, in order to specify properties of the model, a logic that deals with games and strategies is developed. A tableau-based proof system is given for the logic, which can serve as a basis for a model checking algorithm. This approach allows us to model a wide range of security protocol types and verify different properties instead of using a variety of methods as is currently the practice. Furthermore, the analyzed protocols are specified using only the simple arrow notation heavily used by protocol designers and by practitioners.
Distal pancreatectomy with preservation of the spleen
Authors: Warshaw Andrew L.
Published: October 2009

Distal pancreatectomy (resection of the pancreatic body and tail) can be performed with or without preservation of the spleen. Splenic preservation has the advantages of fewer postoperative complications such as abscesses in the resection bed, shorter length of hospitalization, and avoidance of the long‐term risk of post‐splenectomy sepsis related to encapsulated bacteria. Two techniques can be used to save the spleen: either by dissecting out the splenic artery and vein with division of the arterial and venous branches between the pancreas and the splenic artery and vein; or by resecting the splenic artery and vein along with the pancreas but with careful preservation of the vascular collaterals in the splenic hilum, which allows the spleen to survive on the short gastric vessels (Warshaw technique). The latter method has been shown to be associated with a shorter operation, less blood loss, and a shorter hospitalization. In general the Warshaw technique is easier, especially for laparoscopic pancreatectomy. The subsequent appearance of enlarged gastric veins (varices) is to be expected as a consequence of loss of the splenic vein but has not led to bleeding from these natural collaterals during long‐term follow up.
EU-Russia Relations: Between Cooperation and Confrontation
Authors: Lucas Edward
Published: October 2009

Drawing on his experiences as a journalist in Eastern Europe, the author describes Eastern perceptions of the West before and after the collapse of Communism in 1989. Although the West has often taken its political and economic system for granted, those living behind the Iron Curtain clearly recognised the advantages in quality of life and personal freedom made possible under democracy. However, since 1989 the Western model of capitalism and the rule of law has grown threadbare, losing much of the credibility it once held. It is important that we re-establish the moral confidence we once had in our democratic system and recover the necessary enthusiasm to make capitalism work properly.
Sorting out glycosylation enzymes in the Golgi apparatus
Authors: Nilsson Tommy , Au Catherine E. , Bergeron John J.M.
Published: October 2009

The study of glycosylation and glycosylation enzymes has been instrumental for the advancement of Cell Biology. After Neutra and Leblond showed that the Golgi apparatus is the main site of glycosylation, elucidation of oligosaccharide structures by Baenziger and Kornfeld and subsequent mapping of glycosylation enzymes followed. This enabled development of an in vitro transport assay by Rothman and co‐workers using glycosylation to monitor intra Golgi transport which, complemented by yeast genetics by Schekman and co‐workers, provided much of the fundamental insights and key components of the secretory pathway that we today take for granted. Glycobiology continues to play a key role in Cell Biology and here, we look at the use of glycosylation enzymes to elucidate intra Golgi transport.
Multiple routes of protein transport from endosomes to the trans Golgi network
Authors: Pfeffer Suzanne R.
Published: October 2009

Proteins use multiple routes for transport from endosomes to the Golgi complex. Shiga and cholera toxins and TGN38/46 are routed from early and recycling endosomes, while mannose 6‐phosphate receptors are routed from late endosomes. The identification of distinct molecular requirements for each of these pathways makes it clear that mammalian cells have evolved more complex targeting mechanisms and routes than previously anticipated.
Using the Rapid HIV Test to Rescreen Women in the Third Trimester of Pregnancy
Authors: Criniti Shannon M. , Aaron Erika , Levine Amy B.
Published: October 2009

Antiretroviral therapy during pregnancy in HIV‐infected women has dramatically reduced the rate of mother to child HIV transmission in the United States. National guidelines strongly recommend universal HIV testing of all pregnant women with repeat screening in the third‐trimester in high‐risk populations. To determine patient attitudes towards third‐trimester rescreening, a convenience sample was recruited during routine prenatal visits at an urban clinic and participants were surveyed to determine attitudes about HIV third‐trimester retesting, acceptability of the rapid HIV testing, condom use, and knowledge of partner's HIV status during pregnancy. Participants were offered a third‐trimester rapid HIV retest with the option to decline the test. Eighty pregnant women participated; 95% agreed to be retested with a rapid HIV test, 100% received immediate HIV results, and 91% reported that the rapid test was less stressful than conventional testing. There were no seroconversions. Although 35% did not know their partner's HIV status, 57% of these women reported never using condoms during pregnancy. There was a significant association between reported stage of behavior change and reported likelihood of using condoms. We found that rescreening with the rapid HIV test in the third trimester of pregnancy was well accepted and is important to prevent perinatal HIV transmission.
A Critical Appraisal of Guidelines for Antenatal Care: Components of Care and Priorities in Prenatal Education
Authors: Hanson Lisa , VandeVusse Leona , Roberts Joyce , Forristal Amanda
Published: October 2009

There are a variety of published prenatal care (PNC) guidelines that claim a scientific basis for the information included. Four sets of PNC guidelines published between 2005 and 2009 were examined and critiqued. The recommendations for assessment procedures, laboratory testing, and education/counseling topics were analyzed within and between these guidelines. The PNC components were synthesized to provide an organized, comprehensive appendix that can guide providers of antepartum care. The appendix may be used to locate which guidelines addressed which topics to assist practitioners to identify evidence sources. The suggested timing for introducing and reinforcing specific topics is also presented in the appendix. Although education is often assumed to be a vital component of PNC, it was inconsistently included in the guidelines that were reviewed. Even when education was included, important detail was lacking. Addressing each woman's needs as the first priority was suggested historically and remains relevant in current practice to systematically provide care while maintaining the woman as the central player. More attention to gaps in current research is important for the development of comprehensive prenatal guidelines that contribute effectively to the long‐term health and well‐being of women, families, and their communities.
A Framework for Enhancing and Assessing Cultural Competency Training
Authors: Lie Désirée
Published: October 2009

The globalization of medical practice using accepted evidence‐based approaches is matched by a growing trend for shared curricula in medicine and other health professions across international boundaries. Interest in the common challenges of curricular design, delivery and assessment is expressed in conferences and dialogues focused on topics such as teaching of professionalism, humanism, integrative medicine, bioethics and cultural competence. The spirit of collaboration, sharing, acknowledgment and mutual respect is a guiding principle in cross‐cultural teaching. This paper uses the Tool for Assessing Cultural Competency Training to explore methods for designing and implementing cultural competency curricula. The intent is to identify elements shared across institutional, national and cross‐cultural borders and derive common principles for the assessment of learners and the curricula. Two examples of integrating new content into existing clerkships are provided to guide educators interested in an integrated and learner‐centered approach to assimilate cultural competency teaching into existing required courses, clerkships and elective experiences. The paper follows an overarching principle that “every patient–doctor encounter is a cross‐cultural encounter”, whether based on ethnicity, age, socioeconomic status, sex, religious values, disability, sexual orientation or other differences; and whether the differences are explicit or implicit.
Arboreal Metaphors and the Divine Body Traditions in the Apocalypse of Abraham
Authors: Orlov Andrei
Published: October 2009

The first eight chapters of the Apocalypse of Abraham, a Jewish pseudepigraphon preserved solely in its Slavonic translation, deal with the early years of the hero of the faith in the house of his father Terah.1 The main plot of this section of the text revolves around the family business of manufacturing idols. Terah and his sons are portrayed as craftsmen carving religious figures out of wood, stone, gold, silver, brass, and iron. The zeal with which the family pursues its idolatrous craft suggests that the text does not view the household of Terah as just another family workshop producing religious artifacts for sale. Although the sacerdotal status of Abraham's family remains clouded in rather obscure imagery, the authors of the Slavonic apocalypse seem to envision the members of Terah's household as cultic servants whose “house” serves as a metaphor for the sanctuary polluted by idolatrous worship. From the very first lines of the apocalypse the reader learns that Abraham and Terah are involved in sacrificial rituals in temples.2 The aggadic section of the text, which narrates Terah's and Abraham's interactions with the “statues,” culminates in the destruction of the “house” along with its idols in a fire sent by God. It is possible that the Apocalypse of Abraham, which was written in the first centuries of the Common Era,3 when Jewish communities were facing a wide array of challenges including the loss of the Temple, is drawing here on familiar metaphors derived from the Book of Ezekiel, which construes idolatry as the main reason for the destruction of the terrestrial sanctuary. Like Ezekiel, the hero of the Slavonic apocalypse is allowed to behold the true place of worship, the heavenly shrine associated with the divine throne. Yet despite the fact that the Book of Ezekiel plays a significant role in shaping the Abrahamic pseudepigraphon,4 there is a curious difference between the two visionary accounts. While in Ezekiel the false idols of the perished temple are contrasted with the true form of the deity enthroned on the divine chariot, the Apocalypse of Abraham denies its hero a vision of the anthropomorphic Glory of God. When in the second part of the apocalypse Abraham travels to the upper heaven to behold the throne of God, evoking the classic Ezekielian description, he does not see any divine form on the chariot. Scholars have noted that while they preserve some features of Ezekiel's angelology, the authors of the Slavonic apocalypse appear to be carefully avoiding the anthropomorphic description of the divine Kavod, substituting references to the divine Voice.5 The common interpretation is that the Apocalypse of Abraham deliberately seeks “to exclude all reference to the human figure mentioned in Ezekiel 1.”6
Errand into the Wilderness: The Cursed Earth as Apocalyptic Road Narrative
Authors: IRELAND BRIAN
Published: October 2009

Mobility is a significant feature of American history and culture. This is reflected in the literature and cinema of the road genre, in influential novels such as Jack Kerouac's On the Road and John Steinbeck's Grapes of Wrath, and in films like Bonnie and Clyde (1967) and Easy Rider (1969). However, when non-Americans create road stories they tend to employ symbols and narratives that are often considered intrinsically American. These storytellers appear to have absorbed or internalized aspects of American national identity, and this is reflected in their work. This is demonstrated in The Cursed Earth, an apocalyptic road story in twenty-five parts, which was published in the British weekly comic 2000AD from May to October 1978. Written by British writer Pat Mills, with contributions from John Wagner and Chris Lowder, The Cursed Earth features the character Judge Dredd, perhaps the most popular and most recognizable icon of British comics of the last thirty years. Through close textual analysis of the Cursed Earth story, this article reveals how thematic elements of the road genre are linked to significant themes in American history and culture.
Predictors of early precocious talking: A prospective population study
Authors: SKEAT JEMMA , WAKE MELISSA , REILLY SHEENA , EADIE PATRICIA , BRETHERTON LESLEY , BAVIN EDITH L. , UKOUMUNNE OBIOHA C.
Published: October 2009

This study examines potential predictors of ‘precocious talking’ (expressive language ⩾90th percentile) at one and two years of age, and of ‘stability’ in precocious talking across both time periods, drawing on data from a prospective community cohort comprising over 1,800 children. Logistic regression was used to examine the relationship between precocious talking and the following potential predictors: gender, birth order, birth weight, non-English speaking background, socioeconomic status, maternal age, maternal mental health scores, and vocabulary and educational attainment of parents. The strongest predictors of precocity (being female and having a younger mother) warrant further exploration. Overall, however, it appears that precocity in early vocabulary development is not strongly influenced by the variables examined, which together explained just 2·6% and 1% of the variation at 1 ; 0 and 2 ; 0 respectively.
Interrelationships of plant health and the sustainability of agriculture, with special reference to plant diseases
Authors: Cook R. James
Published: October 2009

U.S. crops have the potential routinely to produce 15–25% more, and in some cases 100% more, with no more water or fertilizer, but are prevented from doing so by diseases, nematodes, arthropod pests, and weeds. It is not compatible with the goals of a sustainable agriculture to fertilize, cultivate, and water for maximum production, but then allow diseases and pests to limit actual yields to some fraction of what was paid for with the capital investments and agronomic inputs. In eastern Washington and adjacent northern Idaho (The Palouse), wheat generally yields 4,800–6,200 kg/ha in years of normal precipitation (45–55 cm), but yields 6,900–9,000 kg/ha with the same water and fertilizer if the soil is fumigated to eliminate root disease organisms and weeds, and the plants are protected from rusts, pseudocercosporella foot rot, and aphids. Some practical alternatives to soil fumigation (depending on the value of the crop) include crop rotation, tillage, flooding the soil, heating the soil (using clear plastic tarp or by burning residue on the soil surface), and organic amendments that intensify the biological stresses on pathogen propagules in soil. Other disease controls include using pathogen-free planting material, maintaining a diversity of genetic resistance, and adjusting planting date and method of seeding to escape pathogens. Some of the emerging technologies include improved serological and molecular methods for diagnosing pathogens, microorganisms that kill pathogen propagules in soil or protect the plant, simulation models of epidemics to forecast disease outbreaks, and integrated pest management systems. Better experimental a pproaches are needed to identify and determine the priorities of the combinations of biotic and abiotic factors that limit yields, and more attention should be given to holistic plant health care.
Midwestern organic farming: A ten-year follow-up
Authors: Lockeretz William , Madden Patrick
Published: October 2009

A mailed survey was sent to 174 Midwestern organic farmers originally studied in 1977. We obtained information on 133 of this group, 96 of whom are still farming at the same location, although 12 no longer use organic methods. Fifty-eight currently active farmers returned a detailed questionnaire that covered their perceptions of the advantages and disadvantages of organic farming, some of their practices, and their financial status. Most farmers who employed organic farming methods stated they did so out of concern for the health of themselves, their families, and their livestock. Compared to ten years ago, philosophical or religious considerations were less frequently mentioned as an advantage of organic farming. In contrast, some agronomic and management disadvantages of organic f arming were mentioned more often. The farmers now are more tolerant, in principle, of some chemicals not generally accepted in organic farming, but regular use of soluble fertilizers and synthetic pesticides has not increased appreciably. The farmers reported little change in the institutional and social environment for organic agriculture, including available markets, information sources, and the attitudes of their neighbors.
Influence of alternative and conventional agricultural management on soil microbial processes and nitrogen availability
Authors: Doran John W. , Fraser Daniel G. , Culik Martin N. , Liebhardt William C.
Published: October 2009

Microbial activities important to effects on crop productivity and nutrient cycling can be altered by agricultural management practices. This study was conducted to determine whether soil microbial populations and their N cycling activities differ between conventional and alternative management practices. Physical, chemical, and microbial soil properties were measured at soil depth intervals of 0 to 7.5, 7.5 to 15, and 15 to 30 cm at a site in southeastern Pennsylvania during the second and fifth years after conversion from a conventional, chemically intensive system to alternative systems utilizing legumes and animal manure as N sources. In the second year after conversion, populations of fungi and bacteria, dehydrogenase activity, and soil respiration in the surface soil layer were greatest with alternative systems planted to red clover (Trifolium pratense L.). Differences in soil biological factors between management systems were related primarily to crop characteristics and, to a lesser extent, to soil physical properties. Levels of microbial populations and activities with conventional management were the same as with alternative management systems when similar crops such as corn (Zea mays L.) or soybean [Glycine max (L.) Merrill] were grown. Soil NO3-N contents, at most sampling depths, were markedly increased by application of fertilizer N or recent plow-down of red clover or hairy vetch (Vicia villosa Roth). The growth of red clover in the second year or hairy vetch in the fifth year was accompanied by significantly increased microbial biomass and potentially mineralizable N (PMN) reserves in the top 30-cm soil layer-these changes being most pronounced in the surface 0- to 7.5-cm layer. Nitrogen deficiency symptoms and lower corn grain yields in a legume/cash grain rotation as compared with conventional management in the second year were associated with lower soil NO3, levels and a greater proportion of N present as weed biomass and belowground microbial biomass. In 1985, management systems comparisons were limited to corn as the main crop; soil NO3 levels during the growing season were inversely related to soil microbial biomass and PMN levels where hairy vetch was overseeded and incorporated as green manure by plowing before corn planting. Under the conditions of this study, the use of chemicals had little effect on microbial populations, their activity, or the cycling of nitrogen. Cropping systems-in particular, the growth of red clover or hairy vetch—profoundly influenced soil microbial biomass levels and soil pools of organic and available NO3-N during the growing season. Competitiveness of alternative management systems employing legumes as? sources for grain crops may depend largely on the grower's ability to synchronize supplies of available soil N with periods of maximum uptake by grain crops.
Preferences for crop production practices among conventional and alternative farmers
Authors: Buttel Frederick H. , Gillespie Gilbert W.
Published: October 2009

One of the major gaps in the empirical literature comparing conventional and organic farmers is the degree to which conventional farmers would prefer or can be motivated to use reduced-input practices comparable to those of alternative agriculturalists. This paper presents the results of a 1987 survey of a random sample of New York farm operators and a two-thirds sample of the membership list of the New York State chapter of the Natural Organic Farmers Association (NOFA-NY). The results show that while conventional farmers tend to have a lower preference for reduced-input practices than do alternative agriculturalists (NOFA-NY members), conventional farmers tend to prefer pest- and disease-resistant crop varieties, nonpurchased, on-farmproduced sources of fertility, and nonchemical means of disease control over high-input, chemically-based production practices. The largest differences between conventional and alternative agriculturalists are with respect to preferences for weed control practices. For six of the eight practices assessed, operators of small farms (annual gross sales less than $40,000) were intermediate in their preferences between commercial-scale farmers (gross sales $40,000 or more) and alternative agriculturalists. There was, however, virtually no difference between conventional and organic farmers in their tillage practice preferences; similar percentages of the NOFA members and commercial-scale farmers preferred minimum tillage practices, while the percentage of small farmers preferring to use as few tillage operations as possible was lower than that of both commercialscale and organic farmers. Differences between conventional and organic farmers in their production practice preferences are far smaller than differences in their environmental orientations.
Weed seed destruction by arthropods and rodents in low-input soybean agroecosystems
Authors: Brust Gerald E. , House Garfield J.
Published: October 2009

Weed seed consumption experiments involving comparison of rates of seed loss by seed feeders were conducted over a five-week period in low-input (no insecticide, low herbicide usage) conventional- and no-tillage soybean agroecosystems. Seeds of four broadleaf weed species (ragweed[Ambrosia artemisiifoliaL.], pigweed[Amaranthus retroflexusL.], sicklepod[Cassia obtusifoliaL.], and jimsonweed[Datura stramoniumL.]) and one grain crop species (wheat[Triticum aestivumL.]) were provided in a free choice design at densities of 10, 25, and 50 seeds/24 cm3. Approximately 2.3 times more seeds overall, and 1.4 times more large seeds as a group were consumed in notillage systems than in conventional-tillage systems. In our experimental low-input, notillage treatments, large ground beetles (Carabidae: Coleoptera) (15–25 mm) and mice preferentially fed on the larger seed species, while small carabids (< 15 mm), ants and crickets, fed almost exclusively on the smaller seed species. Carabid beetles were responsible for more than half of all seeds consumed. Laboratory and field studies indicated that ground beetles selectively consumed specific seed species. In conventional-tillage, ants were one of the dominant consumers of seeds, suggesting different patterns of resource partitioning in each tillage system. We suggest that selective feeding by arthropod seed feeders, in combination with their high number, could affect the species composition and possibly the abundance of weeds in low-input, no-tillage agroecosystems.
Biological control and holistic plant-health care in agriculture
Authors: Cook R. James
Published: October 2009

Biological control is defined broadly as the “use of natural or modified organisms, genes, or gene products” to reduce the effects of pests and diseases. Physical control is the use of tillage, open-field burning, heat-treatment (pasteurization), and other physical methods, usually to eliminate pests or separate them from the crop. Chemical control is the use of synthetic chemical pesticides to eliminate pests or reduce their effects. The many approaches to biological control can be categorized conceptionally into 1) regulation of the pest population (the classical approach), 2) exclusionary systems of protection (a living barrier of microorganisms on the plant or animal that deters infection or pest attack), and 3) systems of self-defense (resistance and immunization). The agents of biological control include the pest- or disease-agent itself (sterile males or avirulent strains of pathogens), antagonists or natural enemies, or the plant or animal managed or manipulated (immunized) to defend itself. The methods range from 1) conserving and making maximum use of indigenous (resident) biological control through cultural practices, 2) making one-time or occasional introductions of genes or natural enemies that are more or less self-sustaining and 3) making repeated introductions of a biocontrol agent (e.g. a microbial pesticide). Biological, physical, and chemical treatments and pest controls can be integrated into holistic plant-health care also known as integrated crop and pest management. Eight principles of plant health care are offered: 1) know the production limits of the agroecosystem; 2) rotate the crops; 3) maintain soil organic matter; 4) use clean planting material; 5) plant well-adapted, pest-resistant cultivars; 6) minimize environmental and nutritional stresses; 7) maximize the effects of beneficial organisms; and 8) protect with pesticides as necessary.
Use of organic amendments to increase the productivity of sand and gravel spoils: Effect on yield and composition of sweet corn
Authors: Hornick Sharon B.
Published: October 2009

Crops grown on sand and gravel spoil areas are subject to temperature, moisture, and nutrient stresses due to the infertile, acidic, and coarse-textured properties of the spoil material. Additions of organic materials such as feedlot manure and sewage sludge compost applied at rates of 40, 80, and 160 Mg/ha were found to improve these spoil areas by providing (1) a more favorable pH for seedling germination and root development, (2) essential crop nutrients, and (3) a greatly increased water content of the spoils in the treated plots compared to fertilized controls. The manure-treated spoil plots had a higher water content than either the compost-treated spoils or the limed and fertilized control plots. In a drought year when the wastes were reapplied, both grain and stalk yields of sweet corn were highest for the manure-treated plots. The low heavy metal content makes these organic materials safe for use as soil conditioners. In addition, uptake and accumulation of toxic metals by sweet corn is generally less than other crops. The interaction between the kind and rate of organic amendment applied, the amount of rainfall in any given growing period, and the water content of the treated spoils determined the final nutrient composition of the stalks, leaves, and grain, as well as the grain and stalk yield.
Using crop diversity to manage pest problems: Some California examples
Authors: Flint Mary Louise , Roberts Philip A.
Published: October 2009

Moderate to large scale California growers (as well as small scale ones) manipulate cropping patterns in a number of ways to reduce pest problems. Crop rotation, which can be defined as diversifying crops over time, is used to manage selected pests, primarily weeds, pathogens, and nematodes. As a substitute for pesticides, crop rotation has been most rewarding in the control of nematodes; sugarbeet cyst and root knot nematode examples are detailed. Some pests that invade fields from nearby areas can be managed by modifying adjacent cropping patterns or practices; Pierce's disease of grapes, sugarbeet yellows and border harvesting of alfalfa are given as examples. Finally, multiple crops can be grown within a single field or orchard. Although this approach is not widely practiced by many California growers, two examples of systems where intercropping has been shown to limit pest numbers without the use of pesticides are described: intercropping of cotton with alfalfa and companion planting oats when seeding alfalfa. These examples show that using crop diversification to manage pests is feasible, but growers must be strongly motivated to make the necessary changes in cropping patterns. Most of the systems that have been widely adopted are those for which few other economically feasible methods were available.
An analysis of the California market for organically grown produce
Authors: Franco Jacques
Published: October 2009

The market value for organically grown produce in California was estimated to be at least 54 to 68 million dollars at wholesale prices in 1987. This market is rapidly growing. A 41 percent increase in the value of organically grown produce was observed in 1987. When this analysis was completed in early 1988, it was estimated that the wholesale value of the market could exceed $300 million by 1992. A sample analysis of 1986–1987 price and volume for organically grown broccoli showed relatively steady prices and a volume increase of over 50 percent, indicating a similar growth in market demand. Prices for organically grown produce are significantly higher than for conventional produce; however, in spite of high weekly volume volatility, organic prices appear to be less volatile than prices for conventional produce. This paper proposes that the collection, reporting, and analysis of organic produce market data be continued and improved and that new sources of data be integrated to ensure continued availability of timely market information. Availability of more market information should increase efficiency and aid the development of the organic produce industry. The paper also proposes that overall trends in the organic produce industry be systematically monitored by Federal-State Market News and that the increased use of market information by organic growers, growers considering the transition, and other interested parties in the industry be promoted.
Converting stewardship values into policy: The mission of the 1990 Farm Bill
Authors: Kroese Ron
Published: October 2009

Farmers committed to the overall goal of sustainability in agriculture have banded together to support legislative action favorable to that goal. Specific objectives relate to addition of organic amendments to soils to improve fertility, avoidance of excessive use of pesticides and synthetic fertilizers, crop rotation, species diversity among crops, protection of wildlife habitats, and support of family-operated farms. Currently applicable legislation is believed to be unfavorable to some of these objectives and needs modification.
Trees and Sustainable Agriculture
Authors: Schaefer Peter R.
Published: October 2009

In the United States, trees constitute an element in agriculture whose importance has been inadequately appreciated. In actuality, they are highly important in several ways. From the time of the earliest settlements, they have served as a source of building materials and energy. They protect the soil against erosion by wind and water. When used as windbreaks adjacent to crop fields, they protect crops against the damaging effects of wind on crop yields. As windbreaks for livestock, they increase feed conversion efficiency, improve weight gains, and increase the survival rate ofnewborns. They provide habitat for wildlife and contribute aesthetically to the appearance of the countryside. They protect water resources. Trees need to have the story of their great benefits more widely and emphatically told.
Mechanical and cultural weed control in corn and soybeans
Authors: Gunsolus Jeffrey L.
Published: October 2009

Many farmers and consumers are reevaluating chemical weed control because of the environmental risks of herbicides and their influence on farm size and diversity. This paper reviews research of the last 35 years on mechanical and cultural weed control in corn(Zea maysL.)and soybeans(Glycine maxL.).Soybeans can better use the weed control advantages of late planting and narrow row spacing and are less affected by early stand losses from mechanical weed control. In Minnesota, delaying planting to early June allows early germinating weeds to be controlled by preplant tillage but reduces the maximum yield potential of corn by approximately 25 percent and soybeans by approximately 10 percent. Narrow rows allow the crop canopy to close earlier, preventing emerging weeds from developing. However, in a nonchemical weed control system, the row spacing should allow for inter-row cultivation to control weeds that emerge with the crop. Up to a 10 percent reduction in crop stand may be expected in fields that have been rotary hoed. In Minnesota, a 10 percent stand loss results in a 2 percent loss of corn yield potential and no loss of soybean yield potential. Successful mechanical weed control is directly related to the timeliness of the operation. Rotary hoeing is effective on weeds that have germinated but not yet emerged but not on weeds that germinate from deeper than 5 cm, on no-till fields, or on fields with more than 20 to 30 percent crop residue. Inter-row cultivation is most effective on weeds up to 10 to 15 cm tall. Successful nonchemical weed control requires highly refined management skills and is as much an art as a science.
The potential for Swedish farms to eliminate the use of artificial fertilizers
Authors: Granstedt Artur
Published: October 2009

This paper discusses data on plant-nutrient conservation in Sweden between 1950 and 1980 and on plant-nutrient balances in conventional and alternative farming. The amounts of plant nutrients supplied in the form of artificial fertilizer in Sweden increased severalfold between 1950 and 1980. The amounts of N and P applied were four times higher than those recovered in agricultural products. This difference not only represents a loss to farmers but also a burden on the environment. This problem is a consequence of the increased separation of crop management from animal husbandry in Sweden. The flow of plant nutrients through the agroecosystem can be represented as follows: Artificial Fertilizers- > Crop Production-> Animal Husbandry- > Losses (air, water, or immobilization).

This paper suggests that all farms in Sweden can operate effectively without relying on applications of highly soluble plant nutrients. By recirculating plant nutrients in manure and cultivating nitrogen-fixing species, the need for artificial fertilizers can be eliminated while minimizing nutrient losses and their associated adverse effects on the environment. Successful alternative farms provide practical examples of how a farming system can eliminate its dependence on applications of highly soluble plant nutrients by stressing effective nutrient economy and biological activity. The strategies they use include: matching animal management practices to the farm's own production of feed, thereby reducing net removal of plant nutrients per unit area (in Sweden 0.6–0.8 animal units per ha); minimizing nutrient losses through careful manure management and by using cover crops; and supplying N by nitrogen-fixing ley species, and P and K by soil weathering and by applying supplementary soil improvement materials.