bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiac disease in pregnancy. Part 1: congenital heart disease
Authors: Gelson Emily , Johnson Mark , Gatzoulis Michael , Uebing Anselm
Published: February 2007

Key content

Heart disease is now the most common indirect cause of maternal death in the United Kingdom.

Neonatal morbidity and mortality from fetal growth restriction and prematurity are markedly increased in women with heart disease.

Women with congenital heart disease should ideally have a planned pregnancy managed by a multidisciplinary team which includes obstetricians, cardiologists, anaesthetists, neonatologists and midwives.

Learning objectives

To understand the changes to cardiovascular physiology during pregnancy.

To recognise the risk factors for poor pregnancy outcome in cardiac disease.

To understand the general management principles for women with cardiac disease in pregnancy.

Ethical issues

Should we be recommending termination of pregnancy in women with high risk cardiac lesions?

How do we manage women who become pregnant against medical advice?

What is the role of surrogacy in women with high risk cardiac lesions?

Please cite this article as: Gelson E, Johnson M, Gatzoulis M, Uebing A. Cardiac disease in pregnancy. Part 1: congenital heart disease. The Obstetrician & Gynaecologist 2007;9:15–20.
Management of women with inherited bleeding disorders in pregnancy
Authors: Chi Claudia , Kadir Rezan A
Published: February 2007

Key content

Pregnancy in women with inherited bleeding disorders requires specialised and individualised care using a multidisciplinary approach with obstetricians, midwives, haematologists and anaesthetists.

Childbirth presents an intrinsic haemostatic challenge in these women and obstetricians may be the first to encounter haemorrhagic complications.

An understanding and awareness of these disorders and close collaboration between obstetricians and haematologists are essential in ensuring a successful outcome.

Learning objectives

To understand the basic principles in the obstetric management of women with inherited bleeding disorders.

To know the options available for prenatal diagnosis.

To be aware of the increased risk of haemorrhagic complications in these women and their offspring.

Ethical issues

Advances in prenatal diagnosis and treatment of inherited bleeding disorders create complex dilemmas for families affected by these disorders.

Please cite this article as: Chi C, Kadir RA. Management of women with inherited bleeding disorders in pregnancy. The Obstetrician & Gynaecologist 2007;9:27–33.
Reading “Woman”: Book Club Pedagogies and the Literary Imagination
Authors: Twomey Sarah
Published: February 2007

Reading and literary engagement as a negotiated social practice within a reading club can act as a form of pedagogy, able to shape and define new ways of meaning making individually and socially within the public sphere of education. By looking at how particular women have constructed their private literary experiences, I suggest that there is much to be gleaned from these examples that points to reading as a negotiated relational practice, able to provide a reimagining of the social world. A brief historical overview creates a rich context in which to think about reading club pedagogies as an opportunity to negotiate difference and build community within our classrooms.
“Cool” Engagements With YouTube: Part 1
Authors: Trier James
Published: February 2007

This article discusses the participatory potential of YouTube, a social website that allows users to upload, view, and share video clips. The author provides examples of how YouTube was incorporated into a course as part of a “mosh‐pit” pedagogy that involved both students and teachers in engaging with a variety of YouTube videos.
Constructing the Big Picture: A Working Class Family Supports Their Daughter's Pathways to Literacy
Authors: McTavish Marianne
Published: February 2007

This article examines the historical literacy experiences and current literacy practices of the parents of one working class family as they shape the literacy learning of their four‐year‐old daughter. Data collected from field notes, observations, and videotaped interviews of the parents and daughter were analyzed and events sorted into categories congruent with foundational concepts of emergent literacy, such as intentionality, concepts of writing, and concepts of print. Analysis of the data revealed that socioeconomic status or residential location does not determine a child's literacy background and that great variation exists in diverse families. Despite living in communities deemed “at risk,” some families are able to provide activities to support the development of critical early literacy concepts in their children. The article also provides practical suggestions for teachers so that the home, school, and community can work together to foster children's literacy knowledge.
Effect of Autogenous Cortical Bone Particulate in Conjunction With Enamel Matrix Derivative in the Treatment of Periodontal Intraosseous Defects
Authors: Guida Luigi , Annunziata Marco , Belardo Salvatore , Farina Roberto , Scabbia Alessandro , Trombelli Leonardo
Published: February 2007

Background: The aim of the present study was to assess the additional clinical benefit of autogenous cortical bone particulate (ACBP) when added to enamel matrix derivative (EMD), compared to EMD alone, in the treatment of deep periodontal intraosseous defects.

Methods: A total of 28 intraosseous lesions in 27 patients with advanced periodontitis were included in this controlled clinical trial and randomly assigned to the EMD group (14 defects) or to the EMD + ACBP group (14 defects). Immediately before surgery (baseline) and after 6 and 12 months, probing depth (PD), clinical attachment level (CAL), and gingival recession (REC) were recorded. Radiographic depth of the defect (DEPTH) was also measured at baseline and 12 months post‐surgery.

Results: At 6 and 12 months, PD and CAL significantly improved from baseline in both groups (P <0.000). No significant differences in terms of CAL gain and PD reduction were detected between groups. However, defect distribution according to CAL gain was significantly different between groups (P <0.05). DEPTH significantly decreased from baseline to 12 months in both groups (P <0.000); between‐group differences were not significant. At 12 months, a significantly greater REC increase in the EMD group (1.1 ± 0.7 mm) compared to the EMD + ACBP group (0.3 ± 0.8 mm) was observed (P <0.05).

Conclusions: Both EMD and EMD + ACBP treatments led to a significant improvement in clinical and radiographic parameters at follow‐up with respect to presurgery condition. The combined approach resulted in reduced post‐surgery recession and increased proportion of defects with substantial CAL gain (≥6 mm).
A Familial Pattern of Multiple Idiopathic Cervical Root Resorption in a Father and Son: A 22‐Year Follow‐Up
Authors: Neely Anthony L. , Gordon Sara C.
Published: February 2007

Background: The etiology of idiopathic cervical root resorption has not been elucidated clearly. However, the process has been linked to trauma, intracanal bleaching, and partial‐thickness connective tissue grafts.

Methods: This study describes a familial pattern of multiple idiopathic cervical root resorption in a father and son.

Results: The father was a healthy 63‐year‐old white male who presented with the first resorption lesion in 1983. Twenty‐seven additional lesions were identified on 16 teeth over 22 years. Five teeth were lost as a result of extensive resorption. The son was a healthy 43‐year‐old when a resorption lesion was identified in 1993. A lesion identified on another tooth 12 years later resulted in extraction.

Conclusions: Close relatives of those affected by multiple idiopathic cervical root resorption should be examined carefully for cervical resorption. This study also showed that early treatment can prevent or delay the need for extraction.
Endothelin‐1 and Its Receptors ETA and ETB in Drug‐Induced Gingival Overgrowth
Authors: Tamilselvan S. , Raju Surya Narayana , Loganathan D. , Kamatchiammal S. , Abraham Georgie , Suresh R.
Published: February 2007

Background: The purpose of this study was to study the expression of endothelin‐1 (ET‐1) and its receptors ETA and ETB in normal human gingiva and cyclosporin‐induced gingival fibroblasts.

Methods: Gingival samples were collected from eight normal healthy individuals, eight patients with periodontitis, and eight patients with cyclosporin A (CsA)‐induced gingival overgrowth. Total RNA was extracted from tissue samples, and reverse transcriptase‐polymerase chain reaction was performed for ET‐1, ETA, and ETB. ET‐1 protein was estimated from the tissues by enzyme‐linked immunosorbent assay. The expression of ET‐1 and its receptors was also examined in gingival fibroblast cells treated with CsA.

Results: ET‐1 mRNA expression was significantly higher in patients with CsA‐induced gingival overgrowth (P <0.001) than in patients with periodontitis and the controls. ETA mRNA was expressed more than the ETB in all examined samples. In human gingival fibroblasts, ET‐1 expression was increased with CsA incorporation compared to controls (P <0.001).

Conclusion: These results suggest that CsA can modulate the expression of ET‐1 in gingival fibroblasts and CsA‐induced gingival overgrowth.
Protecting Health Using an Environmental Impact Assessment: A Case Study of San Francisco Land Use Decisionmaking
Authors: Bhatia Rajiv
Published: February 2007

Laws and regulations for an environmental impact assessment enable a health impact assessment whenever physical changes in the environment may significantly affect health. In this case study, I describe 2 instances in which a local public health agency used the procedural requirements for an environmental impact assessment to account for societal-level health determinants that are not traditionally evaluated in land-use decisions.

These examples show that a public health critique can contribute both to the scope of analysis in an environmental impact assessment and to substantive changes in land-use decisions. I have evaluated this health appraisal approach as a form of a health impact assessment and will make recommendations for law, research, and practice that support its technical, cultural, and political feasibility.
Adequacy of Communicating Results From Screening Mammograms to African American and White Women
Authors: Jones Beth A. , Reams Kam , Calvocoressi Lisa , Dailey Amy , Kasl Stanislav V. , Liston Nancy M.
Published: February 2007

Objective. We examined whether African American women were as likely as White women to receive the results of a recent mammogram and to self-report results that matched the mammography radiology report (i.e., were adequately communicated). We also sought to determine whether the adequacy of communication was the same for normal and abnormal results.

Methods. From a prospective cohort study of mammography screening, we compared self-reported mammogram results, which were collected by telephone interview, to results listed in the radiology record of 411 African American and 734 White women who underwent screening in 5 hospital-based facilities in Connecticut between October 1996 and January 1998. Using multivariate logistic regression, we identified independent predictors of inadequate communication of mammography results.

Results. It was significantly more common for African American women to experience inadequate communication of screening mammography results compared with White women, after adjustment for sociodemographic, access-to-care, biomedical, and psychosocial factors. Abnormal mammogram results resulted in inadequate communication for African American women but not White women (P<.001).

Conclusions. African American women may not be receiving the full benefit of screening mammograms because of inadequate communication of results, particularly when mammography results are abnormal.
Association Between the Decline in Workers’ Compensation Claims and Workforce Composition and Job Characteristics in Ontario, Canada
Authors: Breslin F. Curtis , Tompa Emile , Mustard Cameron , Zhao Ryan , Smith Peter , Hogg-Johnson Sheilah
Published: February 2007

We examined associations between workforce demographics and job characteristics, grouped by industrial sector, and declines in workers’ compensation claim rates in Ontario, Canada, between 1990 and 2003. Gender, age, occupation, and job tenure were predictors for claim rates in 12 industrial sectors. The decline in claims was significantly associated with a decline in the proportion of employment in occupations with high physical demands. These findings should generate interest in economic incentives and regulatory policies designed to encourage investment in safer production processes.
William of Ockham and Lorenzo Valla: False Friends. Semantics and Ontological Reduction
Authors: Nauta Lodi
Published: February 2007

At first glance, Lorenzo Valla has much in common with William of Ockham. Both see language as the key to an understanding of the world, criticizing realist ontologies which admit of various abstract entities. Modern scholars have therefore often argued that Valla's transformation of medieval metaphysics and logic is nominalist in spirit and continues Ockhamist nominalism. The article criticizes this widely held interpretation. At closer inspection, Valla's views on ontology and semantics are very different from Ockham's. Apart from the obvious differences in cultural background, they show widely different approaches, methods, and arguments at a more philosophical level.
Tea Processing in China, circa 1885—A Photographic Essay
Authors: Gardella Robert
Published: February 2007

At the time these photographs originated in an unspecified location in late-nineteenth-century China, the Chinese had been cultivating tea (Camellia sinensis) and processing it for almost two millennia. In the latter half of the nineteenth century, after decades of false starts and ceaseless experimentation, British entrepreneurs in India and Ceylon and the Dutch in Java successfully initiated plantation cultivation, pioneered the mechanized processing of black tea, and launched vigorous advertising campaigns to foster corporate sales worldwide.
“A Person of Good Character and Considerable Property”: James Forten and the Issue of Race in Philadelphia's Antebellum Business Community
Authors: Winch Julie
Published: February 2007

James Forten (1766–1842) was in business in Philadelphia for almost half a century. A sailmaker by trade, he invested the profits from his sail-loft in real estate, bank stock, and shares in various ventures, including railroads. He was also a money-lender. Throughout his long career in business, Forten struggled to be accepted as an astute and successful member of the business community who happened to be a man of color. As this essay demonstrates, that was how some of his white peers saw him. To others, however, he was a man of color first and a man of business second.
Patterns of plant species richness in relation to different environments: An appraisal
Authors: Pausas Juli G. , Austin Mike P.
Published: February 2007

Abstract. We review patterns of plant species richness with respect to variables related to resource availability and variables that have direct physiological impact on plant growth or resource availability. This review suggests that there are a variety of patterns of species richness along environmental gradients reported in the literature. However, part of this diversity may be explained by the different types and lengths of gradients studied, and by the limited analysis applied to the data. To advance in understanding species richness patterns along environmental gradients, we emphasise the importance of: (1) using variables that are related to the growth of plants (latitudinal and altitudinal gradients have no direct process impact on plant growth); (2) using multivariate gradients, not single variables; (3) comparing patterns for different life forms; and (4) testing for different shapes in the species richness response (not only linear) and for interaction between variables.
Vegetation change following removal of keystone herbivores from desert grasslands in New Mexico
Authors: Ryerson Daniel E. , Parmenter Robert R.
Published: February 2007

Abstract. Responses of plant communities to mammalian herbivores vary widely, due to variation in plant species composition, herbivore densities, forage preferences, soils, and climate. In this study, we evaluated vegetation changes on 30 sites within and adjacent to the Sevilleta National Wildlife Refuge (SNWR) in central New Mexico, USA, over a 20‐yr period following removal of the major herbivores (livestock and prairie dogs) in 1972–1975. The study sites were established in 1976, and were resampled in 1986 and 1996 using line transect methods. At the landscape scale, repeated measures ANOVA of percentage cover measurements showed no significant overall net changes in total perennial plant basal cover, either with or without herbivores present; however, there was an overall increase in annual forbs and plant litter from 1976 to 1996. At the site scale, significant changes in species composition and dominance were observed both through time and across the SNWR boundary. Site histories varied widely, with sites dominated by Bouteloua eriopoda being the most dynamic and sites dominated by Scleropogon brevifolius being the most persistent. Species‐specific changes also were observed across multiple sites: B. eriopoda cover increased while Gutierrezia sarothrae greatly decreased. The non‐uniform, multi‐directional changes of the sites' vegetation acted to prevent detection of overall changes in perennial vegetation at the landscape level. Some sites displayed significant changes after removal of herbivores, while others appeared to respond primarily to climate dynamics. Certain species that were not preferred by livestock or prairie dogs, showed overall declines during drought periods, while other preferred species exhibited widespread increases during wetter periods regardless of herbivore presence. Therefore, the vegetation dynamics cannot be attributed solely to removal of herbivores, and in some cases can be explained by short‐ and long‐term fluctuations in climate. These results emphasize the variety of responses of sites with differences in vegetation to mammalian herbivores under otherwise similar climatic conditions, and illustrate the value of site‐ and landscape‐scale approaches to understanding the impacts of plant‐herbivore interactions.
Classification of the terrestrial habitats on Marion Island based on vegetation and soil chemistry
Authors: Smith V.R. , Steenkamp Marianna
Published: February 2007

Abstract. Soil chemistry and vegetation data for 176 sites on sub‐Antarctic Marion Island (47° S, 38° E) were subjected to Canonical Correspondence Analysis. 21 habitats in six habitat complexes were recognized from a clustering analysis of the site scores on the canonical axes. Another two habitats and one habitat complex were added to this. The resultant habitat classification closely reflects the between‐habitat variation in the relative magnitudes of the main forcing variables that determine ecological succession on the island (moisture, exposure, parent soil material, salt‐spray and manuring and trampling by seals and seabirds). It can be used by persons with a minimum of botanical or soil expertise. The habitat complexes (number of habitats in complex) are: Coastal Salt‐spray Complex (2); Fellfield (2); Slope (6); Biotic Grassland (3); Biotic Herbfield (3); Mire (6); Polar Desert (1). A key is provided whereby the habitat to which a particular site belongs can be determined using botanical criteria, although infrequently soil moisture and pH information is also needed. Summaries of the soil chemistry and vegetation characteristics of the various habitats are also provided.
How fast is the carousel? Direct indices of species mobility with examples from an Oklahoma grassland
Authors: Palmer M.W. , Rusch G.M.
Published: February 2007

Abstract. Current interest in small‐scale species dynamics has led to a proliferation of mobility indices. We advocate the use of direct measures of mobility such as immigration rate, extinction rate, residence time, and carousel time. We also demonstrate that the null expectation of cumulative frequency under different null models can be calculated explicitly. Species can depart from the commonly‐used ‘random reassignment’ model simply because of longevity, and not mobility per se. We therefore prefer a random immigration null model, which assumes that immigration locations are randomized.

We examined mobility patterns of selected plant species, studied in 256 quadrats of each of four grains (ranging from 1/64 m2 to 1 m2) in an Oklahoma grassland. Residence times and carousel times can be centuries or even millennia for some species. We explore the numerical and biological reasons for relationships between mobility statistics. Mobility statistics are fairly consistent among grains and years, although the residence times of species exhibit some subtle scale dependence. Species depart from a random immigration model very slightly – but the departure is consistent: species tend to re‐occupy previously vacated space more often than expected due to chance. We believe that the use of direct indices will facilitate the study of how species characteristics influence mobility.
Lignotuber size of Erica australis and its relationship with soil resources
Authors: Cruz Alberto , Moreno José M.
Published: February 2007

Abstract. It has been proposed that resprouting after a disturbance would be favoured under conditions of low soil resource availability. In lignotuberous plants of Mediterranean‐type areas, successful resprouting after disturbances such as fire depends on the size of the lignotuber, but little is known about the role of soil resources in determining the relative size of this organ. In this work we tested whether the relative size of the lignotuber in the resprouting shrub Erica australis is related to the availability of soil resources. At each of 13 different sites in Spain, 10 plants were chosen and the sizes of their various parts (above‐ and below‐ground) measured. Additionally, at each site we evaluated soil fertility, foliar N and P concentrations and plant water potential in the middle of the summer. The relationships between lignotuber dimensions and the various plant parts were assessed. In all cases, significant differences between sites were found indicating consistent differences in lignotuber size across the range of plant sizes. This was particularly the case when lignotuber dimensions were expressed as a function of foliar biomass. Lignotuber dimensions relative to foliar biomass were positively correlated with soil pH and negatively with plant water potentials in midsummer. There were, however, no clear relationships between lignotuber relative dimensions and soil N and P contents or other measures of site productivity. In summary, lignotubers were not smaller at more productive sites, in fact they were relatively larger at sites where soils were less acidic, but where plant water conditions were less favourable. These findings contradict predictions made based on current theory on the role of soil fertility allocation to resprouting.
Population dynamics of four understorey shrub species during a 7‐yr period in a primary beech forest
Authors: Kanno Hiroshi , Hara Masatoshi , Hirabuki Yoshihiko , Takehara Akihide , Seiwa Kenji
Published: February 2007

Abstract. Shrubs persist in the understorey layer of forests throughout their lives, while tall trees remain there only during the juvenile stage and then grow into the canopy layer. Thus demographic parameters (recruitment‐, mortality‐, and growth‐rates) of shrub species are expected to differ from those of tall tree species. We investigated aspects of the demography of four dominant deciduous‐shrub species (Viburnum furcatum, Lindera umbellata var. membranacea, Magnolia salicifolia, and Hydrangea paniculata) in Fagus crenata forests at the beginning and at the end of a 7‐yr period in a 1‐ha permanent plot. For each species, the number of stems changed little (within ± 10%) during the study period, while total basal area increased markedly (11.7–33.8%), because (1) new stems continuously recruited by vegetative growth replaced the substantial number of dead stems, and (2) vegetative stems grew vigorously, probably due to nutrient support from parents. The results indicate that these four understorey shrub species have high ability to maintain their population size in the shaded forest understorey. While in each species more than half of the dead stems were standing dead, a substantial proportion of the dead stems (9.0–38.5%) showed signs of mechanical damage, such as stem breakage and suppression by fallen branches or trees. Snow pressure that resulted in decumbent stems was also an important mortality agent for V. furcatum (20.7%) and L. umbellata var. membranacea (5.6%). Probability of damage was constant across all DBH‐classes for all study species. In each species, newly recruited stems and dead stems were spatially aggregated, largely due to habits of vegetative growth and mechanical damage, respectively. This study revealed that several demographic traits, resulting from recruitment by vegetative growth and death by mechanical damage, were shrub‐species specific and markedly different from those of tall tree species.
An extension of presence/absence coefficients to abundance data: a new look at absence
Authors: Tamás Júlia , Podani János , Csontos Péter
Published: February 2007

Abstract. Alternative community analyses, based on quantitative and presence/absence data, are comparable logically if the data type is the only factor responsible for differences among results. For presence/absence indices that consider mutual absences, no quantitative alternatives are known. To facilitate such comparisons, a new family of similarity coefficients is proposed for abundance data. Formally, this extension is achieved by generalizing the four cells of the usual 2 × 2 contingency table to the quantitative case. This implies an expanded meaning of absence: for a given species at a given site it is understood as the difference between the actual value and the maximum detected in the entire study. The correspondence between 10 presence/absence coefficients and their quantitative counterparts is evaluated by graphical comparisons based on artificial data. The behaviour of the new functions is also examined using field data representing post‐fire regeneration processes in grasslands and a chronosequence pertaining to forest regeneration after clear‐cut. The examples suggest that the new coefficients are most informative for data sets with low beta‐diversity and temporal background changes.
Carbon and water relations of juvenileQuercusspecies in tall‐grass prairie
Authors: Danner Brett T. , Knapp Alan K.
Published: February 2007

Abstract.In ecosystems where environments are extreme, such as deserts, adult plant species may facilitate the establishment and growth of seedlings and juveniles. Because high temperatures and evaporative demand characterize tall‐grass prairies of the central United States (relative to forests), we predicted that the grassland‐forest ecotone, by minimizing temperature extremes and moderating water stress, may function to facilitate the expansion ofQuercusspecies into undisturbed tall‐grass prairie. We assessed the carbon and water relations of juvenileQuercus macrocarpaandQ. muhlenbergii, the dominant tree species in gallery forests of northeast Kansas, in ecotone and prairie sites. To evaluate the potentially competitive effects of neighboring herbaceous biomass on these oaks, juveniles (< 0.5 m tall) of both species also were subjected to either: (1) removal of surrounding above‐ground herbaceous biomass, or (2) control (prairie community intact) treatments. Herbaceous biomass removal had no significant effect on gas exchange or water relations in these oak species in either the prairie or the ecotone environment. Although the ecotone did alleviate some environmental extremes, photosynthetic rates and stomatal conductance were ca. 20 % higher (p< 0.05) in both oaks in prairie sites vs. the ecotone. Moreover, although leaf temperatures on average were higher in oaks in the prairie, high leaf temperatures in the ecotone had a greater negative effect on photosynthesis. These data suggest that the grassland‐forest ecotone did not facilitate the growth ofQuercusjuveniles expanding into this grassland. Moreover, the carbon and water relations of juvenile oaks in the prairie appeared to be unaffected by the presence of the dominant C4grasses.
Biodiversity in South African fynbos and Mediterranean heathland
Authors: Ojeda Fernando , Simmons Mark T. , Arroyo Juan , Marañón Teodoro , Cowling Richard M.
Published: February 2007

Abstract. The theory of convergence predicts that, given similar selective regimes, both present and past, unrelated ecological communities will show similar attributes. Mild Pleistocene climate, highly infertile soils, and similar fire regimes explain the remarkable convergence between mediterranean‐type vegetation from South Africa (fynbos) and Australia (kwongan). Heathlands in the Aljibe Mountains, at the western end of the Mediterranean basin, constitute a single vegetation type within the Mediterranean region.

We studied the association between endemism and plant life form in a flora from environmentally similar areas of the South African Cape region (fynbos) and the Aljibe Mountains by contingency table analysis. We included two non‐acid, neighbouring areas to the latter region in the analysis as contrasts. We also compared the patterns of variation in three components of biodiversity (species richness, endemism level and taxonomic singularity) of fynbos and Aljibe heathland woody plant communities along similar soil fertility gradients by means of two‐way ANOVAs.

At the regional (flora) level, our results show two common features in the biological aspects of endemism between the two regions: (1) edaphic endemism and (2) association of endemism with the shrub growth form. At the community level, we detected strong similarities in the patterns of variation of endemism and taxonomic singularity of woody communities from both regions along an ecological gradient related to soil fertility. We interpret these similarities, both at the regional and community levels, as suggestive of convergence between fynbos and Aljibe heathland.
Physical damage by litterfall to canopy tree seedlings in two temperate New Zealand forests
Authors: Gillman Len N. , Ogden John
Published: February 2007

Abstract. The importance of litterfall as an agent of physical damage and mortality to canopy tree seedlings was investigated in two New Zealand forests: Huapai Scientific Reserve, a warm temperate forest and Pureora Forest Park, a cool temperate forest. 200 natural seedlings within the 10–30 cm height class and 200 artificial seedlings, made from plastic straws and wire, were monitored at 4–6 week intervals over two years in each forest. Litterfall was the cause of a significant proportion of seedling mortality in each forest (11–18%).

Seedling growth rates were measured and used to estimate the mortality that a cohort of seedlings may suffer due to litterfall in the time taken to grow through the 10–30 cm height class. Up to 38% mortality due to litterfall may occur to such a cohort at Huapai and up to 29% at Pureora.

Although mortality due to litterfall of natural seedlings was similar in both forests, damage at Huapai (7%/yr) was almost 3 × greater than at Pureora (2.5%/yr) (P < 0.001). Artificial seedlings were damaged due to litterfall at almost five times the rate at Huapai (16%/yr) than at Pureora (3%/yr) (P < 0.0001). The rate of damage to artificial seedlings at Pureora is similar to that reported for a Northern Hemisphere temperate forest, however, the rate of damage to artificial seedlings at Huapai is much greater, and of a similar rate to those reported from tropical forests. The evolutionary and ecological implications of the differences between the rates of damage at Huapai and at Pureora, and the mechanisms promoting litterfall damage to seedlings, are discussed.
Restorative mowing on an abandoned semi‐natural meadow: short‐term and predicted long‐term effects
Authors: Huhta Ari‐Pekka , Rautio Pasi , Tuomi Juha , Laine Kari
Published: February 2007

Abstract. When management, in the form of cattle grazing and mowing, ceases the abundance of competitively superior plant species tends to increase in abandoned semi‐natural meadows. Litter accumulation elevates the soil nutrient levels and hinders seedling recruitment. We surveyed changes in plant cover and species composition of a formerly grazed meadow in permanent plots for six years. Some plots were unmown, while others were mown and raked annually in August. The cover of grasses decreased and herb cover remained unchanged regardless of the treatment. Mowing and raking significantly reduced litter accumulation and increased the number of ground layer species. The expected long‐term effects of abandonment and restorative mowing were studied by calculating the transition probabilities for unmown and mown plots and simulating the course of succession as projected by the transition matrices. During a simulation period of 30 yr, abandonment led to (1) a decrease in the cover of small herbs, (2) a slight increase in the cover of tall herbs and (3) a slight decrease in the cover of grasses. In contrast, the cover of small herbs on the mown plots remained unchanged or slightly increased during the course of simulation. These results suggest that mowing late in the season is primarily a management tool for the maintenance of the existing species diversity and composition. However, it may not be an effective restorative tool to induce overall changes in the resident vegetation of abandoned grass‐dominated meadows. Grazing or mowing early in the season may be more effective in this respect. Consequently, mowing early or, alternatively, late in the season may provide management strategies for the maintenance and restoration of species diversity, respectively.
Effects of disturbance intensity and frequency on early old‐field succession
Authors: Collins B. , Wein G. , Philippi T.
Published: February 2007

Abstract. Early old‐field succession provides a model system for examining vegetation response to disturbance frequency and intensity within a manageable time scale. Disturbance frequency and intensity can interact with colonization and competition to influence relative abundance of earlier and later successional species and determine, respectively, how often and how far succession can be reset. We tested the joint effects of disturbance frequency and intensity on vegetation response (species richness, abundance, canopy structure) during the first six years of succession by clipping the dominant species (D) or all species (T) in spring and fall of each year (S), once per year in summer (Y1), each two years in summer (Y2), or each four years in summer (Y4). Vegetation response reflected disturbance effects on expansion of a later monospecific dominant perennial herb, Solidago altissima, and persistence of the early, richer flora of annuals. A more abundant and taller top Solidago canopy developed on plots clipped each 2 yr or less frequently. Plots clipped yearly or seasonally were richer, but had less abundant, shorter, and differently stratified canopy. Disturbance mediated the relative abundance of early and later successional species; however, frequency and intensity effects were not completely congruent. Persistence of a richer early successional flora increased through the most frequent disturbance (S), and was magnified by disturbance intensity. Disturbance as extreme as clipping all vegetation twice yearly did not cause a drop in species richness, but maintained the early successional community over the first six years of succession. We conclude that clipping disturbance influenced the rate of succession, but the early community could rebound through the range of disturbance frequency and intensity tested.
A grid‐based method for sampling and analysing spatially ambiguous plants
Authors: Fehmi Jeffrey S. , Bartolome James W.
Published: February 2007

Abstract. Spatial data can provide much information about the interrelations of plants and the relationship between individuals and the environment. Spatially ambiguous plants, i.e. plants without readily identifiable loci, and plants that are profusely abundant, present non‐trivial impediments to the collection and analysis of vegetation data derived from standard spatial sampling techniques. Sampling with grids of presence/absence quadrats can ameliorate much of this difficulty. Our analysis of 10 fully‐mapped grassland plots demonstrates the applicability of the grid‐based approach which revealed spatial dependence at a much lower sampling effort than mapping each plant. Ripley's K‐function, a test commonly used for point patterns, was effective for pattern analysis on the grids and the gridded quadrat technique was an effective tool for quantifying spatial patterns. The addition of spatial pattern measures should allow for better comparisons of vegetation structure between sites, instead of sole reliance on species composition data.
Reindeer reduce biomass of preferred plant species
Authors: Bråthen Kari Anne , Oksanen Jari
Published: February 2007

Abstract. Reduced weights in reindeer that graze in pastures with high reindeer densities have raised the question if coastal summer pastures are modified by grazing. To evaluate this, the impact of reindeer grazing on standing crop was measured by the plant intercept method inside and outside grazing exclosures in the understorey of a coastal mountain birch forest in northern Norway. The understories of coastal birch forests are dominated by vascular plants and are important summer pastures to reindeer. Based on the literature, we made a priori categorization of the vascular plant species into functional groups of preferred forage, less preferred forage and forage of unknown value to reindeer.

Intercept frequency was measured within the same plots on three occasions in the summer of 1996. At the end of the grazing season, total standing crop was 33% lower in open plots compared to plots protected by exclosures. However, the reduction varied between the functional groups, with only preferred forage plants being significantly reduced in standing crop (by 49%).

Results suggest that reindeer have a strong annual impact on most of the preferred forage species. However, some of the preferred graminoids are tolerant of grazing and dominate the understorey despite decades of high grazing pressure. We suggest that current grazing pressure is favouring the establishment of a few grazing tolerant graminoids, and that this reduces the forage plant variability. The results are discussed in relation to the grazing optimization hypothesis and the potential importance of plant variability for pasture quality.
Regeneration strategies of dominant boreal forest dwarf shrubs in response to selective removal of understorey layers
Authors: Hautala H. , Tolvanen A. , Nuortila C.
Published: February 2007

Abstract.The deciduousVaccinium myrtillusand the evergreenVaccinium vitis‐idaeawere subjected to five removal treatments of understorey layers: control, removal of the moss layer, removal of the field layer, removal of both moss and field layers and removal of moss, field and humus layers. A second factor, sowing, was included to investigate sexual reproduction after disturbance. Density of new ramets and seedlings and growth of annual shoots were studied for the first two growing seasons, whereas cover was measured for five growing seasons after disturbance treatment.

Initially, vegetative production of new ramets and species cover increased rapidly in all disturbed plots, except for the most severe treatment, in which production of new ramets was virtually absent throughout the study. Full recovery following removal of the field layer only or both field and moss layers was reached after four years forV. myrtillus. V. vitis‐idaearecovered more quickly, after one year (removal of field layer only) and four years (removal of field and moss layers). The relative growth ofV. myrtillusandV. vitis‐idaeaincreased in the latter treatment in terms of production of annual shoots and length of annual shoots, respectively. Seedling density increased after sowing in the most severe treatment. The results underscore the importance of vegetative growth for recovery of these species at moderate‐level disturbances. The high rate of sexual reproduction in the most severe treatment implies that strong mechanical disturbance is needed to enhance the establishment of new genotypes in these species.
New Interpretations of Mimbres Public Architecture and Space: Implications for Cultural Change
Authors: Creel Darrell , Anyon Roger
Published: February 2007

Recent excavations and reanalysis of existing data on communal pit structures provide intriguing insights into ritual and cultural developments over a period of about 350 years, from A.D. 800 to 1140, in the Mimbres Valley of southwestern New Mexico. In the middle of this period, people shifted dwellings from pithouses to pueblos, a shift previously viewed as the pivotal transformation of Mimbres society. In this paper we show that significant changes in Mimbres society began in the A.D. 800s. Trends in the construction methods of communal pit structures, the placement of dedicatory items within them, their ritual retirements, and their long-lived significance within Mimbres villages, reflect other changes that occurred in Mimbres society. We contend that in the A.D. 800s, rapid change based on strong connections with the Hohokam of southern Arizona and agricultural intensification began a trajectory that culminated in the Classic Mimbres pueblos of the A.D. 1000s and early 1100s.
Isotopic Evidence for Diet in the Seventeenth-Century Colonial Chesapeake
Authors: Ubelaker Douglas H. , Owsley Douglas W.
Published: February 2007

Excavations of colonial period sites in Maryland and Virginia have produced human remains dating to the seventeenth century. In this study, we analyze stable isotopes of carbon and nitrogen from these remains to explore aspects of the diets of the individuals represented. Analyses of both stable carbon and nitrogen isotopes were conducted on preserved protein while stable carbon isotope analysis was also conducted on preserved biological apatite. Carbon isotope values (δ13N‰) ranged from -10.5 to -20.5 for collagen and -5.1 to -12.5 for bioapatite. Nitrogen isotope values (δ15N‰) ranged from 9.9 to 14.4. The data suggest dietary diversity among the individuals examined. Three factors contribute to this diversity: the availability of maize, variation in immigration histories of the individuals, and the differing lengths of time they spent in the American colonies.
The Shaman-Priests of the Casas Grandes Region, Chihuahua, Mexico
Authors: VanPool Christine S.
Published: February 2007

The Casas Grandes culture flourished between two well-known regions: Mesoamerica and the North American Southwest. An analysis of Medio period (A.D. 1200-1450) pottery suggests that Paquimé, the center of the Casas Grandes world, was dominated by shaman-priests. The pottery includes images that document a “classic shamanic journey” between this world and the spirit world. These images can be connected to the leaders of Paquimé and to valuable objects from West Mexico, indicating that the Casas Grandes leadership had more in common with the Mesoamerican system of shaman-leaders than with the political system of the Pueblo world of the North American Southwest.
Large-Game Hunting, Gender-Differentiated Work Organization, and the Role of Evolutionary Ecology in California and Great Basin Prehistory: A Reply to Broughton and Bayham
Authors: Hildebrandt William R. , McGuire Kelly R.
Published: February 2007

We are pleased that Broughton and Bayham acknowledge that there was an increase in large-game hunting during the Middle Archaic (ca. 4000-1000 B.P.) in California and the Great Basin that reached proportions greater than any other interval during the Holocene. They argue, however, that this was simply the result of changing climatic conditions, and that the larger social context of hunting plays little or no role in this development. The following discussion identifies several weaknesses in their environmental determinism, and shows how a more comprehensive analysis of genders differentiated fitness and work organization provides greater explanatory power than the narrow, fauna-based approach they advocate.
The Ventana Complex: New Dates and New Ideas on Its Place in Early Holocene Western Prehistory
Authors: Huckell Bruce B. , Haynes C. Vance
Published: February 2007

Radiocarbon dating of charcoal samples and a re-examination of the artifacts from the Volcanic Debris layer in Ventana Cave were conducted in 1992-1994. The goal of this research was to better understand the chronological position and cultural affinities of the Ventana Complex, the name applied to the assemblage recovered from the Volcanic Debris. Ten new Accelerator Mass Spectrometry (AMS)14C ages suggest that the Volcanic Debris accumulated between approximately 8800 B.P. and 10,500 B.P., and the lack of stratigraphic ordering of the dates indicates that the Volcanic Debris was subjected to considerable turbation as it accumulated. This turbation may have led to the incorporation of bones of extinct fauna from an underlying conglomerate deposit rich in horse remains, creating the impression of their association with artifacts. The artifacts are probably the product of episodic, special-purpose occupations spanning centuries or millennia. Technological and morphological studies of the stone tools indicate few similarities with classic Paleoindian industries, and greater similarities to early Holocene Archaic occupations in the Great Basin and Southwest. Correlations of the Ventana Cave stratigraphy with that of southeastern Arizona and with the late Pleistocene and Holocene record of Northern Hemisphere climate are explored.
Cultural Transmission and Stochastic Network Growth
Authors: Bentley R. Alexander , Shennan Stephen J.
Published: February 2007

Archaeological theory has traditionally presupposed the existence of “battleship curves” in stylistic evolution, with little understanding about what governs the width (variant frequency) or length (variant lifespan) of these curves. In terms of these variables, we propose that there is a testable difference between independent decisions, unbiased transmission, and biased transmission in cultural evolution. We expect independent decision making to be represented by an exponential distribution of variant prevalence in the population. In contrast, unbiased transmission tends to be characterized by a power law or log-normal distribution of prevalence, while biased transmission should deviate significantly from the unbiased case. The difference between these categories may be fundamental to how cultural traits spread and persist. In order to make analytical predictions for unbiased transmission, we adapt a model of stochastic network growth that, by quantitatively demonstrating the inherent nonlinearity in unbiased transmission, can explain why a few highly popular styles can be expected to emerge in the course of cultural evolution. For the most part, this model predicts the frequencies of pottery decorations remarkably well over a 400-year span of Linearbandkeramik settlement in the Merzbach valley. Because the highest frequencies of actual motifs are somewhat less than predicted by our unbiased transmission model, we identify an anti-conformist, or pro-novelty, bias in the later phases of the Neolithic Merzbach Valley.