bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation and Analysis of Conjunctive Use with MODFLOW's Farm Process
Authors: Hanson R. T. , Schmid W. , Faunt C. C. , Lockwood B.
Published: June 2010

The extension of MODFLOW onto the landscape with the Farm Process (MF‐FMP) facilitates fully coupled simulation of the use and movement of water from precipitation, streamflow and runoff, groundwater flow, and consumption by natural and agricultural vegetation throughout the hydrologic system at all times. This allows for more complete analysis of conjunctive use water‐resource systems than previously possible with MODFLOW by combining relevant aspects of the landscape with the groundwater and surface water components. This analysis is accomplished using distributed cell‐by‐cell supply‐constrained and demand‐driven components across the landscape within “water‐balance subregions” comprised of one or more model cells that can represent a single farm, a group of farms, or other hydrologic or geopolitical entities. Simulation of micro‐agriculture in the Pajaro Valley and macro‐agriculture in the Central Valley are used to demonstrate the utility of MF‐FMP. For Pajaro Valley, the simulation of an aquifer storage and recovery system and related coastal water distribution system to supplant coastal pumpage was analyzed subject to climate variations and additional supplemental sources such as local runoff. For the Central Valley, analysis of conjunctive use from different hydrologic settings of northern and southern subregions shows how and when precipitation, surface water, and groundwater are important to conjunctive use. The examples show that through MF‐FMP's ability to simulate natural and anthropogenic components of the hydrologic cycle, the distribution and dynamics of supply and demand can be analyzed, understood, and managed. This analysis of conjunctive use would be difficult without embedding them in the simulation and are difficult to estimate a priori.
The Notching Rule for Subordinated Debt and the Information Content of Debt Rating
Authors: John Kose , Ravid S. Abraham , Reisel Natalia
Published: June 2010

This paper provides new evidence regarding the information content of debt ratings. We show that noninvestment grade subordinated issues are consistently priced too high (the yield is too low), and the reverse is true for some investment grade bonds. We relate this empirical bias to a notching rule of thumb that is used in order to rate subordinated debt without expending additional resources for information production. We propose an explanation for these findings based upon a balance between an attempt to please the companies that pay the raters versus a concern for lawsuits and regulatory investigations should ratings be too optimistic.
Split Bond Ratings and Information Opacity Premiums
Authors: Livingston Miles , Zhou Lei
Published: June 2010

This paper examines the relationship between split bond ratings and bond yields at the notch level for newly issued corporate bonds. We find that split rated bonds average a 7‐basis‐point yield premium over nonsplit rated bonds of similar credit risk. The yield premium increases from 5 basis points for one‐notch splits to 15 (20) basis points for two‐notch (three‐notch) splits. These findings indicate that investors demand higher yields for split rated bonds to compensate for the information opacity of such bonds. In addition, the yield premium for split rated bonds is higher during economic recessions, indicating investors are more risk averse during economic downturns. Consequently, split ratings impose higher borrowing costs for firms, especially during economic downturns.
Callable Bonds Revisited
Authors: Banko John C. , Zhou Lei
Published: June 2010

In light of the dramatic changes in the callable bond market, we reexamine the determinants of callable bonds. Using data from 1980‐2003, we find that callable bonds are often issued by firms with both information asymmetry and underinvestment problems. However, risk‐shifting does not appear to be a major factor. Furthermore, we find that interest rate hedging is an important factor for investment‐grade bonds and when interest rates are high but not so for below‐investment‐grade bonds or when rates are low.
The Impact of Financing Surpluses and Large Financing Deficits on Tests of the Pecking Order Theory
Authors: De Jong Abe , Verbeek Marno , Verwijmeren Patrick
Published: June 2010

This paper extends the basic pecking order model of Shyam‐Sunder and Myers by separating the effects of financing surpluses, normal deficits, and large deficits. Using a panel of US firms over the period 1971‐2005, we find that the estimated pecking order coefficient is highest for surpluses (0.90), lower for normal deficits (0.74), and lowest when firms have large financing deficits (0.09). These findings shed light on two empirical puzzles: 1) small firms, although having the highest potential for asymmetric information, do not behave according to the pecking order theory, and 2) the pecking order theory has lost explanatory power over time. We provide a solution to these puzzles by demonstrating that the frequency of large deficits is higher in smaller firms and increasing over time. We argue that our results are consistent with the debt capacity in the pecking order model.
Habitat vulnerability in conservation planning—when it matters and how much
Authors: Visconti Piero , Pressey Robert L. , Bode Michael , Segan Daniel B.
Published: June 2010

Addressing the vulnerability of areas to habitat loss remains a challenge for conservation planners. Different areas are often assumed equally vulnerable to habitat loss or, worse, conservation attention focuses on remote, unproductive areas contributing little to minimizing biodiversity loss. Understanding vulnerability is crucial to planning but gathering the required information can be time consuming and expensive; and any data on vulnerability will be uncertain. We investigated the circumstances in which including vulnerability data produces better conservation decisions. We found that it is best to use existing information on vulnerability only when uncertainty is less than 20%–30%. With higher uncertainty and large spatial variance in vulnerability, it is best to improve vulnerability data before making conservation decisions. Otherwise, it is best to ignore vulnerability and consider only biodiversity value. Other important factors are whether reservation displaces or inhibits habitat loss and the correlation between biodiversity value and vulnerability.
Optimizing for multiple species and multiple values: tradeoffs inherent in ecosystem‐based fisheries management
Authors: Kellner Julie B. , Sanchirico James N. , Hastings Alan , Mumby Peter J.
Published: June 2010

Although a consensus in marine science is developing on the need to adopt ecosystem‐based fishery management, few studies try to quantify the context‐specific gains from implementing it. Using a multi‐species bioeconomic model for a Caribbean reef community, we determine the optimal harvesting rates for predator and prey species and ask how this more comprehensive optimization differs from traditional single‐species approaches. We also identify tradeoffs when the objective of the manager includes nonfishing values. We find that the optimal solution when accounting for nonfishing values can include temporary or permanent fishing moratoriums in contrast to continuous fishing at low levels when only fishing profits are considered. We also show that the greatest gains from ecosystem‐based fishery management are not from improved estimation of the trophic coupling, but from reforming the social and economic management of individual fish stocks and by explicitly incorporating a broader set of values into management decisions.
From Partnership to Parenthood: A Review of Marital Change Across the Transition to Parenthood
Authors: Kluwer Esther S.
Published: June 2010

The transition to parenthood is generally seen as one of the most challenging events in the early stages of marriage. But is it really that detrimental for marriage and do all couples go through the same changes? This article provides a state‐of‐the‐art review of research on marital change across the transition to parenthood. I first address to what extent the transition to parenthood affects the partner relationship. I then consider factors that explain why some couples fare better or worse than others across the transition to parenthood. Two factors that play a central role are (1) adaptive processes and (2) personal and situational characteristics. Finally, this article builds an evidence‐based case for an integrative model of the transition to parenthood.
Quantum cohomology of [ℂN/μr]
Authors: Bayer Arend , Cadman Charles
Published: June 2010

We give a construction of the moduli space of stable maps to the classifying stack Bμr of a cyclic group by a sequence of rth root constructions on $\overline {M}_{0, n}$. We prove a closed formula for the total Chern class of μr-eigenspaces of the Hodge bundle, and thus of the obstruction bundle of the genus-zero Gromov–Witten theory of stacks of the form [ℂN/μr]. We deduce linear recursions for genus-zero Gromov–Witten invariants.
Periodic Solutions and Nonlinear Analysis Used for Evaluating of Dynamic Properties of Glued-Laminated Beams Reinforced With GRP
Authors: Naghipour M. , Kachapi SHA. Hashemi , Nematzadeh M.
Published: June 2010

Analytical investigations into dynamic properties of glued-laminated beams reinforced with various lay ups of e-glass reinforced epoxy polymer composites are discussed. The exp-function method is used to obtain generalized solitonary solutions and periodic solutions for nonlinear evolution equations arising in mathematical physics using symbolic computation. By using this method, natural frequency and dynamic responses of the wood-composite beams are obtained. The existing data obtained from our published work, the grindosonic instrument, and also the data from the beams tested using the power spectral density method is used for validity of analytical method. The data from finite element method as a numerical method was also employed. The comparison indicated that the proposed exp-function method could be effectively used to establish the natural frequency and dynamic properties of glulam reinforced composite beams when conducted in nonlinear equation forms.
Bistable Trypanosome Switch
Authors: VanHook Annalisa M.
Published: June 2010

A glycosome-associated switch regulates transition of trypanosomes from host- to vector-specific forms.
Wnt Signaling in Axial Patterning and Regeneration: Lessons from Planaria
Authors: De Robertis Edward M.
Published: June 2010

Positional information generated by Wnt signaling determines whether heads or tails will form in wounded flatworms.
Synergistic Activities of an Efflux Pump Inhibitor and Iron Chelators against
Pseudomonas aeruginosa
Growth and Biofilm Formation
Authors: Liu Yang , Yang Liang , Molin Søren
Published: June 2010

The efflux pump inhibitor phenyl-arginine-β-naphthylamide (PAβN) was paired with iron chelators 2,2′-dipyridyl, acetohydroxamic acid, and EDTA to assess synergistic activities against
Pseudomonas aeruginosa
growth and biofilm formation. All of the tested iron chelators synergistically inhibited
P. aeruginosa
growth and biofilm formation with PAβN. PAβN-EDTA showed the most promising activity against
P. aeruginosa
growth and biofilm formation.
Ability of
Candida albicans
Mutants To Induce
Staphylococcus aureus
Vancomycin Resistance during Polymicrobial Biofilm Formation
Authors: Harriott Melphine M. , Noverr Mairi C.
Published: June 2010

Candida
albicans
and
Staphylococcus
aureus
form vigorous polymicrobial biofilms in serum, which may serve as the source of coinfection in patients. More importantly,
S. aureus
is highly resistant to vancomycin during polymicrobial biofilm formation, with no decreases in bacterial viability observed with up to 1,600 μg/ml drug. In these mixed-species biofilms,
S. aureus
preferentially associates with
C. albicans
hyphae, which express a variety of unique adhesins. We tested
C. albicans
mutants deficient in transcriptional regulators of morphogenesis (
CPH1
and
EFG1
) and biofilm formation (
BCR1
) to investigate the role of hyphae in mediating polymicrobial biofilm formation. These mutants also have reduced expression of hypha-specific adhesins. The ability to form polymicrobial biofilms correlated with the ability to form hyphae in these mutants. However, only mutants that could adhere to the abiotic surface could induce
S. aureus
vancomycin resistance, regardless of the presence of hyphae. In examining factors that may mediate interspecies adhesion, we found that the
C. albicans
ALS family of adhesins (Als1 to Als7 and Als9) was not involved, and neither was the hypha-specific adhesin Hwp1. Therefore, polymicrobial biofilm formation and subsequent antibiotic resistance is a multifactorial process that may require a unique combination of fungal and/or bacterial adhesins.
In Vitro
Antifungal Activities of Isavuconazole and Comparators against Rare Yeast Pathogens
Authors: Guinea Jesús , Recio Sandra , Escribano Pilar , Peláez Teresa , Gama Beatriz , Bouza Emilio
Published: June 2010

We compared the
in vitro
activities of isavuconazole, posaconazole, voriconazole, and fluconazole against
Dipodascus capitatus
(
n
= 21),
Saccharomyces cerevisiae
(
n
= 20),
Rhodotorula mucilaginosa
(
n
= 18), and
Trichosporon
spp. (
n
= 15). The MIC
50
s, MIC
90
s, and MIC ranges (in μg/ml) obtained using the CLSI M27-A3 procedure were as follows: isavuconazole, 0.125, 0.5, and ≤0.015 to 2; posaconazole, 0.5, 2, and ≤0.015 to >16; voriconazole, 0.125, 2, and ≤0.015 to 8; and fluconazole, 4, >128, and ≤0.125 to >128. Isavuconazole showed potent activity against the isolates studied.
Comparative Analyses of the Bacterial Microbiota of the Human Nostril and Oropharynx
Authors: Lemon Katherine P. , Klepac-Ceraj Vanja , Schiffer Hilary K. , Brodie Eoin L. , Lynch Susan V. , Kolter Roberto
Published: June 2010

The nose and throat are important sites of pathogen colonization, yet the microbiota of both is relatively unexplored by culture-independent approaches. We examined the bacterial microbiota of the nostril and posterior wall of the oropharynx from seven healthy adults using two culture-independent methods, a 16S rRNA gene microarray (PhyloChip) and 16S rRNA gene clone libraries. While the bacterial microbiota of the oropharynx was richer than that of the nostril, the oropharyngeal microbiota varied less among participants than did nostril microbiota. A few phyla accounted for the majority of the bacteria detected at each site:
Firmicutes
and
Actinobacteria
in the nostril and
Firmicutes
,
Proteobacteria
, and
Bacteroidetes
in the oropharynx. Compared to culture-independent surveys of microbiota from other body sites, the microbiota of the nostril and oropharynx show distinct phylum-level distribution patterns, supporting niche-specific colonization at discrete anatomical sites. In the nostril, the distribution of
Actinobacteria
and
Firmicutes
was reminiscent of that of skin, though
Proteobacteria
were much less prevalent. The distribution of
Firmicutes
,
Proteobacteria
, and
Bacteroidetes
in the oropharynx was most similar to that in saliva, with more
Proteobacteria
than in the distal esophagus or mouth. While
Firmicutes
were prevalent at both sites, distinct families within this phylum dominated numerically in each. At both sites there was an inverse correlation between the prevalences of
Firmicutes
and another phylum: in the oropharynx,
Firmicutes
and
Proteobacteria
, and in the nostril,
Firmicutes
and
Actinobacteria
. In the nostril, this inverse correlation existed between the
Firmicutes
family
Staphylococcaceae
and
Actinobacteria
families, suggesting potential antagonism between these groups.

IMPORTANCE
The human nose and throat, though connected, contain distinct niches that are important sites of colonization by pathogenic bacteria. For many of these pathogens, colonization increases the risk of infection. Most research on the microbiota of nose and throat habitats has focused on carriage of one or a few pathogens. We hypothesized that increased knowledge of the composition of the complex bacterial communities in which these pathogens reside would provide new insights into why some individuals become colonized with pathogens, while others do not. Indeed, in the nostril microbiota of participants, there was an inverse correlation between the prevalences of the
Staphylococcaceae
family (
Firmicutes
), whose members include important pathogens, and the
Corynebacteriaceae
and
Propionibacteriaceae
families (both
Actinobacteria
), whose members are more commonly benign commensals. An improved understanding of competitive bacterial colonization will increase our ability to define predispositions to pathogen carriage at these sites and the subsequent risk of infection.
Action indicators for injury prevention
Authors: MacKay J Morag , Macpherson Alison K , Pike Ian , Vincenten Joanne , McClure Rod
Published: June 2010

There is considerable confusion about the nature of indicators, their use in the injury field and surprisingly little discussion about these important tools. To date discussions of injury indicators have focused on the content and presentation of health outcome measures and on the dearth of data on exposure measures. Whereas these are valuable measures and assessing the optimal use of available routinely collected data in forming indicators is important, they do not provide sufficient information to support comprehensive prevention efforts, nor do they harness the full potential of indicators as tools to support prevention efforts. This paper provides an overview of the characteristics and uses of indicators for the field of injury prevention in order to make the case for action indicators and provide a framework for their appropriate use.
Sleep habits and excessive daytime sleepiness correlate with injury risks in the general population in Taiwan
Authors: Chen Ying-Yeh , Wu Kevin Chien-Chang
Published: June 2010

Objective

To explore the relationship between sleeping habits, excessive daytime sleepiness (EDS), and different injury risks in the general population of Taiwan.

Design

Cross-sectional national data from the Taiwan Social Trend Survey conducted in 2005 by interviews using validated inventories.

Setting

Population-based face-to-face interviews at participants' residences.

Participants

36 473 Taiwanese citizens aged 15 years or older.

Exposure Measures

Self-reported EDS was measured using the Epworth sleepiness scale. Other sleep-related problems investigated included self-reported sleep quality (assessed by the insomnia self-assessment inventory) and self-reported inadequate sleep duration (<7 h).

Main Outcome Measures

Self-reported major injuries that required medical attention.

Results

Considering all sleep-related problems together, multivariate logistic regression analyses showed that EDS and poor sleep quality were significant predictors of higher risks of various injuries. EDS predicted major traffic injuries (odds ratio (OR) 1.62, 95% CI 1.29 to 2.02) and major fall injuries (OR 1.49, 95% CI1.20 to 1.84). Those with poor sleep quality tended to have traffic injuries (OR 1.67, 95% CI 1.41 to 1.99) and major fall injuries (OR 1.73, 95% CI 1.44 to 2.07).

Conclusions

EDS and sleep quality are associated with the occurrence of a variety of injuries in Taiwan's general population.
The measurement of long-term health-related quality of life after injury: comparison of EQ-5D and the health utilities index
Authors: Polinder Suzanne , Haagsma Juanita A , Bonsel Gouke , Essink-Bot Marie-Louise , Toet Hidde , van Beeck Ed F
Published: June 2010

Objective

Empirical head-to-head comparison of the health utility index (HUI) mark 2 and 3 and the EuroQol-5D (EQ-5D) in injury patients of all severity levels to obtain more insight into the strengths and limitations of the multi-attribute utility measures (MAUI) to estimate utility losses in injury populations.

Design

A self-assessment survey that included the EQ-5D, HUI2 and HUI3 to measure generic health-related quality of life.

Patients

Injury patients in The Netherlands 2 years after they attended the emergency department.

Main Outcome Measures

Shannon's index and Shannon's evenness index were used to assess absolute and relative informativity, both for the summary scores and by dimension. The study also analysed convergent and construct validity of the MAUI.

Results

Mean summary scores significantly differed between the instruments, with highest summary scores for HUI2 (0.88), followed by HUI3 (0.80) and EQ-5D (0.78). Absolute and relative informativity by dimension was highest for the HUI3 descriptive system. The HUI3 was most sensitive for ageing and comorbidity. The largest differences between the MAUI were found for pain/discomfort and anxiety/depression/emotion. The largest differences in discriminative power between EQ-5D and HUI (mark 2 and 3) were seen for skull–brain injury, internal organ injury and upper extremity fractures.

Conclusions

Different MAUI resulted in significantly different summary scores. The instruments and their dimensions performed differently for injury severity levels, ageing, comorbidity and injury groups. A combination of the HUI and EQ-5D should be used in studies on injury-related disability, because the combination covers all relevant health dimensions, is applicable in all kinds of injury populations and in widely different age ranges.
Injury-related childhood mortality in migrant households in a southern city of China
Authors: Wang H , Smith G A , Stallones L , Xiang H
Published: June 2010

Background

Sporadic evidence from China suggests that migrant children are at higher risk of injury-related mortality than local indigenous children.

Methods

Child deaths from 2004 to 2008 were provided by the Shenzhen Women and Child Health Surveillance System. Population data for children 1–4 years old were obtained from the Shenzhen Bureau of Statistics and number of live births was obtained from birth registration records. All-cause and injury-related childhood mortality rates and death causes were calculated and compared.

Results

A total of 3774 deaths were identified. All-cause mortality rates per 10 000 dropped significantly from 66.28 (95% CI 60.50 to 72.06) in infants (<1 year old) and 7.40 (95% CI 6.16 to 8.64) in early childhood (1–4 years old) in 2004 to 40.42 (95% CI 37.31 to 43.53) and 3.97 (95% CI 3.36 to 4.58) in 2008. However, injury-related mortality rates did not change significantly from 2.36 (95% CI 1.27 to 3.45) in infants and 2.97 (95% CI 2.19 to 3.76) in early childhood in 2004 to 2.00 (95% CI 1.31 to 2.69) and 2.00 (95% CI 1.56 to 2.43) in 2008. Injury-related mortality rates were significantly higher among migrant children (p<0.05). Drowning and traffic crashes were the top two causes of early childhood injury deaths; suffocation was the leading cause of infant injury deaths.

Conclusion

Migrant children were at significantly higher risk of injury-related mortality than local indigenous children. Injury prevention in Shenzhen should target drowning and traffic safety among young children and suffocation among infants as top priorities.
Reporting on road traffic injury: content analysis of injuries and prevention opportunities in Ghanaian newspapers
Authors: Yankson Isaac Kofi , Browne Edmund N L , Tagbor H , Donkor Peter , Quansah Robert , Asare George Ernest , Mock Charles N , Ebel Beth E
Published: June 2010

In order to analyse traffic injury reporting in Ghanaian newspapers and identify opportunities for improving road safety, the content of 240 articles on road traffic injury was reviewed from 2005 to 2006 editions of two state-owned and two privately owned newspapers. The articles comprised reports on vehicle crashes (37%), commentaries (33%), informational pieces (12%), reports on pedestrian injury (10%), and editorials (8%). There was little coverage of pedestrian injuries, which account for half of the traffic fatalities in Ghana, but only 22% of newspaper reports. Only two articles reported on seatbelt use. Reporting patterns were similar between public and private papers, but private papers more commonly recommended government action (50%) than did public papers (32%, p=0.006). It is concluded that Ghanaian papers provide detailed coverage of traffic injury. Areas for improvement include pedestrian injury and attention to preventable risk factors such as road risk factors, seatbelt use, speed control, and alcohol use.
Physiological responses of three northern conifers to rapid and slow induction of moisture stress
Authors: Buxton G. F. , Cyr D. R. , Dumbroff E. B. , Webb D. P.
Published: June 2010

The response of black and white spruce and jack pine to slow and rapid induction of moisture stress was evaluated during soil drying and exposure to liquid cultures containing polyethylene glycol 8000. Marked changes in water, osmotic, and pressure potentials were observed in all three species, but water potentials were the most sensitive indicators of moisture stress. Osmotic potentials were sensitive to mild stress in polyethylene glycol (−400 kPa), but they held relatively steady at higher stress intensities (−800 to −1600 kPa). Large decreases in osmotic potential were recorded in white spruce and jack pine during severe drying stress late in the drought period and these changes were accompanied by large decrements in water and pressure potentials. Significant changes in osmotic potential were not observed in black spruce prior to seedling death. Losses in pressure potential were only observed at −1600 kPa of polyethylene glycol stress, although wilting in young tissue was apparent at lower stress intensities. Pressure potentials of plants in the soil-drying test fell well below those recorded in the polyethylene glycol study. The highest resistance to loss of turgor and the maximum adjustment to moisture stress were observed in white spruce. Shoot growth and transpiration declined in the three conifers at relatively low stress intensities. Total chlorophyll and the chlorophyll stability index decreased during drought, but the differences recorded among species were not clearly related to observed differences in drought tolerance. Cation concentrations did not change during stress.
Inorganic carbon accumulation and photosynthesis by Chlorella pyrenoidosa
Authors: Shelp Barry J. , Canvin David T.
Published: June 2010

Photosynthesis and intracellular inorganic carbon were measured in air-grown and high CO2 grown Chlorella pyrenoidosa under various environmental and chemical treatments, using a silicone-oil centrifugation technique. At alkaline pH, both cell types accumulated inorganic carbon, presumably [Formula: see text], in a light-dependent and saturable process. The formation of the internal pool was kinetically observed and was used as a substrate for photosynthesis. Rates of carbon influx always exceeded the rates of photosynthesis in air-grown cells, whereas in high CO2 grown cells influx rates closely paralleled photosynthesis. At acid pH inorganic carbon was also accumulated, but the characteristics of this accumulation differed from that seen at alkaline pHs. It was more rapid and was not affected by any of the treatments that affected accumulation at higher pHs. However, the internal inorganic carbon pool provided CO2 for photosynthesis. It is suggested that this accumulation can be explained partly by CO2 diffusion according to the pH gradient existing across the plasmalemma and partly by nonspecific binding of CO2 to proteins and amino acids. The results are consistent with the view that air-grown C. pyrenoidosa is capable of utilizing either CO2 or [Formula: see text] as a substrate for the internal inorganic carbon pool.
Differential uptake and toxicity of ionic and chelated copper in Triticum aestivum
Authors: Taylor Gregory J. , Foy Charles D.
Published: June 2010

Plants of Triticum aestivum L. cv. Atlas-66 were grown in nutrient solutions containing 0–50 μM Cu as CuSO4 or 0–800 μM Cu as Cu-EDTA to compare the toxic effects of ionic and chelated Cu when yield reductions were similar in magnitude. Plants exposed to 50 μM CuSO4 accumulated 43 ± 6 μg g−1 Cu in leaf tissues and 2300 ± 130 μg g−1 in root tissues. Plants injured by CuSO4 showed acute signs of Cu toxicity; leaves showed mild necrosis and symptoms of induced Fe deficiency and root growth and lateral root initiation were inhibited. Concentrations of Fe, Mn, and Mg in leaves of plants injured by CuSO4 were low, possibly leading to nutrient deficiencies. Concentrations of Ca in leaves were also low, but were above levels considered to be deficient. Plants exposed to 800 μM Cu-EDTA accumulated 260 ± 7 μg g−1 Cu in leaf tissues and 6600 ± 1200 μg g−1 Cu in root tissues. Despite higher tissue concentrations of Cu, plants injured by Cu-EDTA showed systemic toxicity symptoms, possibly reflecting induced Fe deficiency as the primary toxic effect. Leaves of plants injured by Cu-EDTA showed mild necrosis and symptoms of induced Fe deficiency, root growth was depressed (but to a lesser extent than with CuSO4), and lateral root initiation was unaffected. Concentrations of Fe in leaves of plants injured by Cu-EDTA were lower than plants grown with micronutrient levels of Cu, while concentrations of Mn, Ca, and Mg in leaves of Cu-EDTA injured plants were higher. Differential toxicity of CuSO4 and Cu-EDTA could occur if Cu-EDTA were absorbed across the plasma membrane as an intact complex or if the primary toxic effect of CuSO4 and Cu-EDTA were on membrane structure and (or) function.
Canadian and some extralimital Paraphaeosphaeria species
Authors: Shoemaker R. A. , Babcock C. E.
Published: June 2010

Six species of Paraphaeosphaeria O. Eriksson are redescribed, keyed, and illustrated: P. castagnei (Dur. & Mont.) O. Eriksson, P. glauco-punctata (Grev.) n. comb. (= P. rusci (Wallr.) O. Eriksson), P. michotii (West.) O. Eriksson (= Leptosphaeria iwamotoi Miyake, = L. zeae Stout, = Pleospora monilispora Fuckel), P. microspora (Ell. & Ev.) n. comb., P. obtusispora (Speg.) Hedjaroude, and P. vectis (Berk. & Br.) Hedjaroude. Two species are excluded: P. longispora (Wegelin) Crivelli and P. oblongata (Niessl) Crivelli.
Crown architecture of Larix laricina saplings: sylleptic branching on the main stem
Authors: Remphrey W. R. , Powell G. R.
Published: June 2010

Sylleptic branching occurred on the current (1983) height-growth increment in 44% of Larix laricina (Du Roi) K. Koch (tamarack) saplings sampled from a natural population near Fredericton, N.B. Although variable, the occurrence and amount of syllepsis tended to increase with parental shoot length. Sylleptic shoots were generally located on the proximal halves of parental shoots. In most cases, the proximally and distally situated sylleptic shoots were somewhat shorter than those in between. The lengths of terminal shoots arising from sylleptic shoots were significantly correlated with parental shoot length, current tree leader length, and location of the branch on its parental shoot. The lengths and elevation angles of terminal extensions from sylleptic shoots tended to be greater than those from nonsylleptic (proleptic) lateral long shoots borne in the same region of the height-growth increment. Architectural characteristics of the extensions resembled those of the more distal proleptic shoots, which develop into major branches. Thus, an additional complement of major lateral branches appeared to be developing where syllepsis occurred. Quantitative relationships depicting sylleptic branching patterns were incorporated into a previous architectural model and simulations of crown architecture which included syllepsis were obtained.
Histogenèse et organogenèse de Picea pungens cultivé in vitro
Authors: Chrétien Louise , Vieth Joachim
Published: June 2010

The histological events occurring both prior to and during the neoformation of adventitious buds on portions of vegetative buds of Picea pungens Engelmann are analysed. The formation of a superficial zone of meristematic tissue in needle primordia and needle primordium callus is followed by the differentiation of meristemoids and buds.
The effects of CO2 and membranes on sporulation in axenic cultures of flax rust
Authors: Boasson Rosalinda , Shaw Michael
Published: June 2010

Uredospore production by axenically grown flax rust (Melampsora lini (Ehrenb.) Lev.) was measured as carotenoids (extinction units at 458 nm) per milligram protein. Sporulation was not affected by raising (flushing with 1–5% (v/v) CO2 in air) or lowering (KOH well in culture flasks) the level of CO2 in the air space above the cultures. Significant (two- to four-fold) increases in sporulation occurred beneath impermeable membranes of Parafilm or Saran wrap placed on the surface of young (3 weeks from seeding) mycelial mats for 2 weeks. The stimulatory effect was confined strictly to those areas of the mycelial mats in contact with the membranes. Both Parafilm and Saran wrap were easily and cleanly peeled away from the mycelial mats. Permeable Unipore and HVHP membranes, to which the fungus adhered strongly, did not stimulate sporulation. The fungus did not adhere to Unipore or HVHP membranes treated with silicone or paraffin oil; membranes thus treated stimulated sporulation. The stimulatory effect of membranes on sporulation appears to depend on the nature of the contact between the membrane surface and the mycelium and to be unrelated to the effect of the membranes on the diffusion of gases or other volatile substances.
Mycopappus, a new genus of leaf pathogens, and two parasitic Anguillospora species
Authors: Redhead S. A. , White G. P.
Published: June 2010

A new form-genus, Mycopappus, is recognized for fungi producing multicellular, epiphyllous, splash-dispersed propagules previously described under the names Cercosporella alni Dearness and Bartholomew and C. aceris Dearness and Batholomew. Mycopappus alni comb. nov. occurs on Alnus rubra Bong, or A. sinuata (Regel) Rydb. along the Pacific coast from the Alaskan panhandle to Oregon. Mycopappus aceris comb. nov. on Acer macrophyllum Pursh occurs from southern British Columbia to Oregon. Anguillospora vermiformis (Davis) comb. nov. on Alnus rugosa (Du Roi) Spreng. in Wisconsin and A. coryli sp. nov. on Corylus americana Walt, and C. cornuta Marsh, in Wisconsin have been confused with Mycopappus alni. All four species are leaf pathogens.
Effects of sulphur pollution on rates of litter decomposition in a pine forest
Authors: Prescott Cindy E. , Parkinson Dennis
Published: June 2010

Litter decomposition was measured at three "ecologically analogous" pine (Pinus contorta × Pinus banksiana) stands located 2.8 (site 1), 6.0 (site 2), and 9.6 km (site 3) from a sour gas plant in west-central Alberta which has been emitting sulphur dioxide since 1959 and elemental sulphur dust since 1979. Respiration of intact forest floor cores and separated forest floor layers was consistently lowest at site 1 and highest at site 3. Rates of mass loss and respiration of pine needles decomposing in litterbags for 17 months also increased with distance from the gas plant. Decomposition of needles in exchanged litterbags was related primarily to the site of origin during the first few months of decomposition and to the site of placement thereafter. Litter fall rates did not bear any relation to sulphur loading; however, litter accumulation and residence times were greatest at the site nearest the gas plant. These findings indicate that an inhibition of decomposition has occurred in response to elevated levels of sulphur pollution near the gas plant.
Competitive effects on the structure of subalpine meadow communities
Authors: Moral Roger del
Published: June 2010

The effects of competition in a subalpine meadow environment were investigated by comparing within-habitat distributions and species overlap in four communities. Based on experimental studies of these communities, it was hypothesized that structural patterns should be affected by productivity changes. It was determined that such changes are nonlinear and that the most stressed and the most competitive communities share many similar properties. Among closed, relatively productive communities, mean niche width, niche width of competitively inferior species, total overlap, and overlap among weak competitors all declined with increased competitive intensity. In contrast, niche width of dominant species changed little and overlap among space-holding species increased. The use of comparative pattern measures can complement and enhance the analysis of community structure and dynamics based on experimental methods.
SDS–PAGE of seed proteins in Festuca (Poaceae): taxonomic implications
Authors: Aiken S. G. , Gardiner S. E.
Published: June 2010

Taxonomically useful descriptors were provided by the banding patterns of seed storage proteins obtained when extracts of bulked, ungerminated seed samples from commercially available North American native species of Festuca were analyzed by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS–PAGE). The banding patterns for three species of rough fescues (section Breviaristatae Krivot) indicate that although the taxa are closely related, F. campestris Rydb. (2n = 56) does not appear to be an autoploid of either F. altaica Trin. (2n = 28) or F. hallii (Vasey) Piper (2n = 28). A distinct band corresponding to a molecular weight of 57 000 occurred in the seed protein profiles of all native and commercial samples of Festuca L. analyzed. The profile for F. californica Vasey, questionably section Breviaristatae, also has a band at this position, and is very different from that of F. altaica, F. campestris, and F. hallii. Species-specific banding patterns were observed for F. brachyphylla Schultes, F. saximontana Rydb., F. idahoensis Elmer, and F. trachyphylla (Hackel) Krajina (F. ovina L. s.l., F. longifolia Thuill., F. ovina var. duriuscula auct. amer.). The results support the recognition of subgenus Schedonorus (Beauv.) Peter., and sections Breviaristatae Krivot and Festuca. Key words: Poaceae, Festuca, SDS–PAGE seed proteins.
Sporulation in root nodules of actinorhizal plants inoculated with pure cultured strains of Frankia
Authors: Racette Suzanne , Torrey John G. , Berg R. Howard
Published: June 2010

A low level of sporulation was seen to occur consistently within root nodules produced by inoculation with specific pure cultured strains of Frankia. The three Frankia strains, UFGCeI5 from Casuarina equisetifolia, UFGCgI1 from Casuarina glauca, and UFGMuI1 from Myrica pubescens, infect and produce root nodules on a range of actinorhizal host plants. Sporulation was detected in nodules of each host plant examined when the Frankia used for inoculation was one of these three strains. The amount of sporulation that occurred in any particular nodule was so low that it required identification in thin plastic sections prepared for examination at high magnification at the light microscope level. These strains, unlike other isolates studied, appear to be genetically predisposed to sporulate in the host root nodules. All three strains also show spontaneous spore release in culture. Key words: actinorhizal plants, endosymbiont, Frankia, sporulation.
Localization of amylase activity in cotyledons of germinated mung bean seeds
Authors: Kaneko Yasuko , Matsushima Hisashi , Morohashi Yukio
Published: June 2010

Developmental patterns of amylase activity in mung bean (Vigna radiata) cotyledons were observed by histochemical methods. In axis-attached cotyledons, the development of amylase activity and the decompostion of starch grains occurred first in cells located farthest from vascular bundles, and 3 days after imbibition, starch granules appeared to remain intact only in two to three cell layers around the vascular bundles. In axis-detached cotyledons, on the other hand, no conspicuous change in amylolytic activity was detected. When cotyledons were allowed to imbibe water through the surface not covered by the seed coat, amylase activity developed, even if they were detached from the axis. However, the developmental patterns of the activity were quite different from those with attached cotyledons; high amylase activity was detected in the cell layers beneath the epidermis of the surface not covered by the seed coat. These histochemical observations are related to previous results of biochemical experiments. Key words: amylase development, cotyledons, germination, histochemistry, mung bean, Vigna radiata.
Taxonomy and ultrastructure of some Gomphonema and Gomphoneis taxa from the upper Laurentian Great Lakes
Authors: Kociolek John P. , Stoermer Eugene F.
Published: June 2010

Ten Gomphonema taxa and four taxa of Gomphoneis from the upper Laurentian Great Lakes are considered. Gomphonema taxa include five new species and one new variety and a new record for the Great Lakes. Two new Gomphoneis taxa are described. SEM study of Gomphonema species indicates that all have occluded puncta. Occlusions may occur on the inside or outside of the valve; their position is species-specific. One Gomphoneis species possesses a stigma that is multiperforate, a condition not previously reported for the genus. Many species of both genera have extra silica on the outer valve surface. Key words: Bacillariophyceae, diatoms, Gomphoneis, Gomphonema, Laurentian Great Lakes, new species, taxonomy, SEM, ultrastructure.
Embryogenèse somatique et regénération de plantes à partir de protoplastes issus de suspensions cellulaires de céleri (Apium graveolens)
Authors: Watin-de-Pontfarcy C. , Bigot C.
Published: June 2010

Protoplasts were isolated from cell suspensions of Apium graveolens L. variety rapaceum (celeriac) initiated and subcultured on Gamborg medium (B5) with 2,4-dichlorophenoxyacetic acid (2.26 μM) and 6-benzylaminopurine (1.1 μM). The microcalli fraction above 450 μm was taken from 6-days-old cell suspensions and put into an enzyme mixture of cellulase Onozuka R-10 (2%) and pectolyase Y-23 (0.1%). Protoplasts were cultured on Lazar et al. modified medium with 2,4-dichlorophenoxyacetic acid (2.26 μM), naphthaleneacetic acid (0.89 μM), and zeatin (0.5 μM) at a density of 3 × 105∙mL−1. They were kept in darkness at alternating temperatures: 28 and 22 °C during 16 and 8 h, respectively. The culture medium was partially renewed after 7, 14, and 21 days of culture. Cell division rate represented about 30–40% of viable protoplasts. Addition of 2,4-dichlorophenoxyacetic acid (2.26 μM) in the microcalli plating medium improved embryogenic differentiation and subsequent plantlet isolation. Calli from protoplasts showed a variable capacity for somatic embryogenesis on Murashige and Skoog medium containing kinetin (1.4 μM). Plantlet growth was observed more particularly on microcalli plating medium without growth regulators. After acclimatization, a great number of plants with abnormal morphology was noted from calli cultivated on medium with kinetin. No variation of the normal ploidy level (2n = 2x = 22) has been recorded among the examined plants. Key words: Apium graveolens, protoplast, somatic embryogenesis, somaclonal variation, flowering.
Leaf demography and decline of Panicum racemosum populations in coastal foredunes of southern Brazil
Authors: Costa César S. B. , Seeliger Ulrich , Cordazzo César V.
Published: June 2010

We studied the effect of nutrient status and sand movement on the population biology of Panicum racemosum Spreng. over a 5-year period (1982–1986) on mobile, semifixed and fixed coastal foredune habitats in southern Brazil. The soils were deficient in nitrate, phosphate, and potassium (<0.5, 0.2–1.2, and 3–5 mg/kg, respectively) in all habitats, and a gradient of decreasing availability existed from the mobile to the fixed dunes. Half-lives of leaves were shorter in the fixed dune as compared with the mobile dune. Similarly, half-lives of leaves were shorter in summer than in winter. Experiments using cuttings of P. racemosum tillers showed that as P. racemosum plants grew, so did the deposition of sand on mobile foredunes. The mechanical deposition of sand itself did not stimulate P. racemosum growth. The deposition of saline sand provided a substrate that supported vertical growth of P. racemosum rhizomes and tillers and was a source of adsorbed nutrients. Also, active sand deposition limited the invasion of frontal dunes by other species. Panicum racemosum populations changed from "invader" to "mature" to "regressive" age states over a 5-year period, apparently in response to the spatial patterns of sand deposition and salt spray input. Key words: Panicum, leaf demography, growth vigour, sand dunes, temporal changes.
Buried propagule bank of a high subalpine site: microsite variation and comparisons with aboveground vegetation
Authors: Ingersoll Cheryl A. , Wilson Mark V.
Published: June 2010

We assessed the composition and spatial pattern of the persistent buried propagule bank (seeds and vegetative structures) of a treeline site in the Oregon Cascade Mountains. We monitored emergence from soil cores removed from four microsite types and recorded vegetation cover and seedling abundance on the site. Over 3100 seedlings/m2 emerged from the greenhouse soil cores; the seed bank was dominated by Juncus species. Few vegetative sprouts emerged. Vegetated microsites produced significantly more emergents than did bare soils, but even bare soils contained abundant seeds. Overall site cover was low and few seedlings occurred on the site. Discrepancies between aboveground and belowground abundance were common. Phyllodoce empetriformis and Luetkea pectinata were abundant in the vegetation and produced many seeds but were poorly represented in the seed bank and as seedlings on the site. Other species were abundant in the seed bank, but rare in the vegetation. Our results indicate that despite the abundance of seeds in bare soil, colonization is likely to be extremely slow. Key words: seed bank, subalpine, seedlings, microsite, spatial pattern.
Effects of nitrogen addition on the population dynamics and flowering of Pulsatilla vernalis
Authors: Kellner Olle
Published: June 2010

A population of Pulsatilla vernalis (L.) Mill, was studied in permanent plots for 8 years. Half the plots were fertilized with ammonium nitrate (15 g N/m2) at the start of the study. Mortality and natality in the ramet population were very low in both fertilized and control treatments. In contrast, there was a considerable between-year turnover of shoots within ramets in both treatments. The number of shoots increased threefold after fertilization and then gradually decreased to the original level. Flower-bud formation in unfertilized plots was lower in warm and dry years than in cooler, wetter ones. In fertilized plots, flower-bud formation was higher after fertilization irrespective of the climate at the time. The proportion of flower buds grazed was higher in fertilized plots. Even though the species is confined to nitrogen-poor habitats, a single fertilization did not adversely affect its performance. Key words: Pulsatilla vernalis, population dynamics, nitrogen, weather, forestry.
Chrysophycean stomatocyst flora from Elk Lake, Clearwater County, Minnesota
Authors: Zeeb Barbara A. , Smol John P.
Published: June 2010

The paleoecological record preserved in the varved sediments of Elk Lake, Clearwater County, Minnesota, has been used by a large number of researchers to reconstruct past environmental and climatic conditions that have occurred at this important reference site. As part of this interdisciplinary effort, we used the International Statospore Working Group (ISWG) taxonomic guidelines to describe the chrysophycean flora that Elk Lake supported over the last 10 400 years. In total, we identified 56 stomatocyst morphotypes using scanning electron and light microscopy. Over one-third of these morphotypes had not been previously recorded. Key words: stomatocyst, Chrysophyceae, paleolimnology, Minnesota, climatic change.