bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Desiccation on Pyrenoid Structure in the Oceanic Lichen Parmelia Laevigata
Authors: Ascaso C. , Brown D. H. , Rapsch S. 
Published: May 2007

AbstractPhycobiont cells of Parmelia laevigata contain chloroplasts with pyrenoids penetrated by a reticulum of tubules. The occurrence and significance of such tubules in algae is discussed. Although these tubules collapsed in desiccated cells, their lumen reappeared on rehydration. However, in such desiccated cells, pyrenoglobuli did not become peripherally located within the pyrenoid, except when damage occurred to the pyrenoid matrix. Rehydration of desiccated cells reduced the number of pyrenoglobuli per pyrenoid.
Nitrogen Fixation on a Tropical Volcano, La Soufrière (Guadeloupe): The Interaction of Temperature, Moisture, and Light with Net Photosynthesis and Nitrogenase Activity in Stereocaulon Virgatum and Response to Periods of Insolation Shock
Authors: Fritz-Sheridan R. P. , Coxson D. S. 
Published: May 2007

AbstractThe response of net photosynthesis, dark respiration and acetylene reduction to temperature, moisture and light intensity were examined for Stereocaulon virgatum growing in the cloud/shroud zone on the tropical volcano La Soufrière, Guadeloupe, French West Indies. Rates for both acetylene reduction and net photosynthesis were maximal at saturating water contents, a pattern attributed to the finely branched nature of the phyllocladoid branchlets and the exposed position of spherical cephalodia, both of which minimize the formation of surface and interhyphal water films. Under conditions typical of those during cloud/shroud periods (13–16°C), thalli of S. virgatum exhibit many characteristics seen in other shade-tolerant lichen species. Net photosynthesis was light saturated at 300 μmol m−2 s−1 PAR, while the photocompensation point was less than 25 µmol m−2 s−1 PAR. Net photosynthetic uptake of carbon dioxide was optimal at 27–34°C, at which point light saturation was near 700 µmol m−2 s−1 PAR and the photocompensation point between 50 and 100 µmol m−2 s−1 PAR. Thalli of S. virgatin exhibited temperature-dependent sensitivity to high insolation. Only at 20°C were thalli able to tolerate high light exposure without reduction of apparent quantum yield. Exposure to high light intensity at 40°C inhibited the apparent quantum yield by almost 40% and acetylene reduction by 95%. This suggests brief periods of insolation shock may exert an influence disproportionately higher than either their frequency or duration. Thalli are normally exposed to cloud/shroud conditions but net photosynthetic uptake was maximal only during periods of elevated thallus temperature experienced at the onset of an insolation shock. However, with prolonged high insolation exposure and further elevation of thallus temperatures and thallus desiccation, severe impairment of subsequent photosynthetic activity ensues. S. virgatum may be characterized as a shade-tolerant species but its physiology is more adapted in some respects to conditions experienced during rare periods of full insolation.
Variation in Morphology and Functional Traits of Dictyonema Glabratum From Contrasting Habitats in the Venezuelan Andes
Authors: Larcher W. , Vareschi V. 
Published: May 2007

AbstractSpecimens of Dictyonema glabratum from various elevations in the Venezuelan Andes show clear differences in morphology. Optimal development of thalli is attained in the lower Paramo at 3500–3600 m; at the upper altitudinal limit of distribution at about 4300 m only poorly developed thalli are found; in the montane forest zone at about 1700 m the thalli attain about half the average surface area and two thirds of the thickness of those in the optimal habitat. The histological structure of the thalli also shows significant differences. The relative volumes of photobiont to mycobiont, as an indicator of the relationship autotrophism/heterotrophism, is 1.6:1 in specimens from the upper Paramo; 0.9:1 in open habitats on the lower Paramo; 0.5:1 in shaded habitats; and 1.4:1 in the montane forest. The three altitudinal morphotypes are not only distinguished by structure but also by carbon dioxide gaseous exchange patterns. Specimens from the optimal habitat exhibit the highest photosynthetic capacity. The respiration activity reflects a homeostatic adjustment to the prevailing temperature regime: the respiration of specimens from 4300 m at 1°C approximates to same intensity as that of D. glabratum from the lower Paramo zone at 6°C. Nevertheless, metabolic homeostasis is only possible over a narrow temperature amplitude. On account of the large heterotrophic component in lichens, at altitudes below 1500 m where the temperature average is 20°C or more and the nocturnal temperatures are constantly high, the dry matter consumption due to respiration would become extremely high. This suggests that D. glabratum may be limited in its downward distribution by an increasingly unfavourable carbon budget.
Culture of the Cyanobacterial Lichen Peltigera Didactyla From Soredia Under Laboratory Conditions
Authors: Stocker-Wörgötter E. , Türk R. 
Published: May 2007

AbstractSoredia of Peltigera didactyla were cultivated under laboratory conditions in a culture chamber. The developmental stages were observed by light microscopy and macrophotography until thallus formation was achieved; this occurred after a period of five months.
Lasallia Hispanica and Related Species
Authors: Sancho L. G. , Crespo A. 
Published: May 2007

AbstractLasallia hispanica (Frey) Sancho & Crespo comb. nov. is proposed as a result of anatomical and morphological comparisons between it and the related species, L. brigantium Zsch. and L. rossica Dombr. For all three species ecological notes, data on world distributions, and a key are provided.
β-1,4-Glucanase (Cellulase) Location in the Symbionts of Evernia Prunastri
Authors: Yagüe E. , Estévez M. P. 
Published: May 2007

AbstractEvernia prunastri thalli were homogenized and separated into algaland fungal-rich fractions. The former was shown to contain most β-l,4-glucanase (cellulase) activity. The significance of this localization in field material is discussed.
Occurrence and Ecology of the Lichen Lobaria Scrobiculata in Southern Sweden
Authors: Hallingbäck T. 
Published: May 2007

AbstractThe present occurrence and vitality of Lobaria scrobiculata (Scop.) DC. were investigated at 67 localities (50 old and 17 new) in southern Sweden. Before 1950 L. scrobiculata was found at more than 300 localities in southern Sweden. However, it was only confirmed at two out of 50 thoroughly investigated old localities. An investigation of recently found localities (new) and confirmed ‘old’ sites showed that there have been decreases in population size, thallus size, fertility, number of phorophytes, and cliff colonization. In southern Sweden today L. scrobiculata is confined to old deciduous trees in regions with comparatively low air pollution and a high relative humidity. Apothecia have not been found in southern Sweden since 1947, although in the past, fertile material was collected from 35 localities in this region. The author suggests that this species, like many other lichens with the cyanobacterium Nostoc as photobiont, is currently more endangered by air pollution than by any other human activity and that it is seriously endangered in the southern part of Sweden.
Lichens as Biomonitors of Sulphur Dioxide Pollution in La Spezia (Northern Italy)
Authors: Nimis P. L. , Castello M. , Perotti M. 
Published: May 2007

AbstractLichens epiphytic on olive trees were used as biomonitors of sulphur dioxide pollution in La Spezia (Northern Italy). The method adopted was designed to avoid subjectivity at all stages, from the sampling strategy to data analysis. Thus, lichen data are expressed by an index that does not depend on any sensitivity scale; data analysis relies on multivariate methods of classification and ordination, and the pollution maps have been produced by automatic mapping programmes. The index, based on the frequency of species within a sampling grid, showed a very high statistical correlation with pollution data measured by recording gauges. The results of classification and ordination indicate that Parmelia caperata is the species with a distribution best related to the lichen index. The quality of air pollution data obtained from biomonitors is discussed.
Lecanora Strobilinoides, a New Lichen Species From North-Eastern Spain
Authors: Giralt M. , Gomez-Bolea A. 
Published: May 2007

AbstractA new species of Lecanora with a yellowish green thallus, Lecanora strobilinoides Giralt & Gomez-Bolea sp.nov. is described. It was found only in SE Catalonia (NE Spain) at low and middle altitudes, growing on bark and lignum of trees and shrubs, mainly on Pinus halepensis and Quercus ilex. Closely related to Lecanora strobilina (Sprengel) Kieffer, it is easily separated by its asci, with (12–)16(–32) ascospores, that are smaller and frequently 1-septate.
National Trace-Element Air Pollution Monitoring Survey Using Epiphytic Lichens
Authors: Sloof J. E. , Wolterbeek H. Th. 
Published: May 2007

AbstractTwo national monitoring surveys were carried out within 5 years, using Parmelia sulcata as a biomonitor of trace-element air pollution. The method of sampling was standardized. The lichen samples were analysed by neutron activation analysis. Local variations in element concentrations in lichens from various deciduous tree species from several sampling sites were established. The geographical concentration patterns obtained from the lichen data sets agreed with the element concentration gradients obtained from one dispersion model and measured data of atmospheric concentrations and deposition. Comparison of the two lichen data sets showed the relationship of the geographical concentration patterns with time. Combination of the available data gave insight into the possibility of localization of pollution sources.
Mannitol-1-Phosphate Dehydrogenase in Pseudevernia Furfuracea
Authors: Jensen Manfred , Feige Guido B. , Waterkotte Anna 
Published: May 2007

AbstractMannitol-1-phosphate dehydrogenase [EC 1.1.1.17] activity was demonstrated in extracts of Pseudevernia furfuracea and Hypogymnia physodes. The reaction was found to be highly substrate specific for fructose-6-phosphate/NADH or mannitol-1-phosphate/NAD+. The pH optimum for fructose-6-phosphate reduction was 7.1, and apparent Km values were 1.2 mM for fructose-6-phosphate and 20 μM for NADH. The reaction did not require Mg++ or Ca++. For conversion of mannitol-1-phosphate into mannitol, the occurrence of mannitol-1-phosphatase in Pseudevernia furfuracea is postulated.
Nitrogen Analyses of New Zealand and Antarctic Lichens
Authors: Greenfield L. G. 
Published: May 2007

AbstractThe results of nitrogen (N) analyses of 14 New Zealand and 23 Antarctic lichens are reported. Eight percent of the total lichen N occurs in the form of amino sugars, 5° as nucleic acids and 80° as proteins and amino acids. It is concluded that when lichens decompose they may represent a good N resource that may be important in ecosystems.
The Influence of pH and Lichen Metabolites (Vulpinic Acid and (+) Usnic Acid) on the Growth of the Lichen Photobiont Trebouxia 1rregularis.
Authors: Bačkor M. , Hudá J. , Repčák M. , Ziegler§ W. , Bačkorová M. 
Published: May 2007

AbstractThe quantitative response to two lichen metabolites, vulpinic acid and (+) usnic acid, on biomass production by the photobiontTrebouxia irregularis, isolated from the lichenCladina mitis, was determined experimentally. The presence of usnic acid resulted in inhibition of photobiont growth, and the effect depended on the pH of the culture medium. The concentration effect of usnic acid was observed. The application of vulpinic acid almost completely inhibited the growth ofT.irregularisand no significant differences were found among samples at different medium pH values.
K201 (JTV519) suppresses spontaneous Ca2+ release and [3H]ryanodine binding to RyR2 irrespective of FKBP12.6 association
Authors: Hunt Donald J. , Jones Peter P. , Wang Ruiwu , Chen Wenqian , Bolstad Jeff , Chen Keyun , Shimoni Yakhin , Chen S. R. Wayne 
Published: May 2007

K201 (JTV519), a benzothiazepine derivative, has been shown to possess anti-arrhythmic and cardioprotective properties, but the mechanism of its action is both complex and controversial. It is believed to stabilize the closed state of the RyR2 (cardiac ryanodine receptor) by increasing its affinity for the FKBP12.6 (12.6 kDa FK506 binding protein) [Wehrens, Lehnart, Reiken, Deng, Vest, Cervantes, Coromilas, Landry and Marks (2004) Science 304, 292–296]. In the present study, we investigated the effect of K201 on spontaneous Ca2+ release induced by Ca2+ overload in rat ventricular myocytes and in HEK-293 cells (human embryonic kidney cells) expressing RyR2 and the role of FKBP12.6 in the action of K201. We found that K201 abolished spontaneous Ca2+ release in cardiac myocytes in a concentration-dependent manner. Treating ventricular myocytes with FK506 to dissociate FKBP12.6 from RyR2 did not affect the suppression of spontaneous Ca2+ release by K201. Similarly, K201 was able to suppress spontaneous Ca2+ release in FK506-treated HEK-293 cells co-expressing RyR2 and FKBP12.6. Furthermore, K201 suppressed spontaneous Ca2+ release in HEK-293 cells expressing RyR2 alone and in cells co-expressing RyR2 and FKBP12.6 with the same potency. In addition, K201 inhibited [3H]ryanodine binding to RyR2-wt (wild-type) and an RyR2 mutant linked to ventricular tachycardia and sudden death, N4104K, in the absence of FKBP12.6. These observations demonstrate that FKBP12.6 is not involved in the inhibitory action of K201 on spontaneous Ca2+ release. Our results also suggest that suppression of spontaneous Ca2+ release and the activity of RyR2 contributes, at least in part, to the anti-arrhythmic properties of K201.
Tapping Toddlers' Evolving Semantic Representation via Gesture
Authors: Capone Nina C. 
Published: May 2007

Purpose
This study presents evidence that gesture is a means to understanding the semantic representations of toddlers.

Method
The data were part of a study of toddlers' word learning conducted by N. C. Capone and K. K. McGregor (2005). The object function probe from that study was administered after 1 exposure and after 3 exposures to objects. Here, toddlers' gestures were described and their gesture–speech combinations were analyzed as a function of instruction and time.

Results
A large proportion of toddlers gestured. Gestures were iconic and deictic, but toddlers produced more iconic gestures than previously reported. Consistent with studies of older children, toddlers produced gesture–speech combinations that reflected their learning state.

Conclusion
Gesture can be both a source of semantic knowledge and an expression of that knowledge. Gesture provides a window onto evolving semantic representations and, therefore, can be 1 method of assessing what a child knows at a time when oral language skills are limited and are, perhaps, an unreliable indicator of what the child knows. Embodied knowledge may underlie the use of gesture. Clinical implications are discussed.
A normal form for elliptic curves
Authors: Edwards Harold 
Published: May 2007

The normal form

x
2

+

y
2

=

a
2

+

a
2

x
2

y
2

x^2 + y^2 = a^2 + a^2x^2y^2

for elliptic curves simplifies formulas in the theory of elliptic curves and functions. Its principal advantage is that it allows the addition law, the group law on the elliptic curve, to be stated explicitly
\[

X
=

1
a

⋅

x

y
′

+

x
′

y

1
+
x
y

x
′

y
′

,

Y
=

1
a

⋅

y

y
′

−
x

x
′

1
−
x
y

x
′

y
′

.

X = \frac 1a \cdot \frac {xy’ + x’y}{1 + xyx’y’}, \quad Y = \frac 1a \cdot \frac {yy’ - xx’}{1 - xyx’y’}.

\]
The

j
j

-invariant of an elliptic curve determines 24 values of

a
a

for which the curve is equivalent to

x
2

+

y
2

=

a
2

+

a
2

x
2

y
2

x^2 + y^2 = a^2 + a^2x^2y^2

, namely, the roots of

(

x
8

+
14

x
4

(x^8 + 14x^4

+
1

)
3

−

j
16

(

x
5

−
x

)
4

+ 1)^3 - \frac j{16}(x^5 - x)^4

. The symmetry in

x
x

and

y
y

implies that the two transcendental functions

x
(
t
)

x(t)

and

y
(
t
)

y(t)

that parameterize

x
2

+

y
2

=

a
2

+

a
2

x
2

y
2

x^2 + y^2 = a^2 + a^2x^2y^2

in a natural way are essentially the same function, just as the parameterizing functions

sin
⁡
t

\sin t

and

cos
⁡
t

\cos t

of the circle are essentially the same function. Such a parameterizing function is given explicitly by a quotient of two simple theta series depending on a parameter

τ
\tau

in the upper half plane.
Asymptotic analysis for shear waves in a fluid‐filled borehole
Authors: Yao Gui‐jin , Wang Ke‐xie , Ma Jun , Yang Bao‐jun , Zhang Hai‐rong 
Published: May 2007

ABSTRACTWe focus on the theoretical analysis of the resonance phenomena and the geometric attenuation behaviour of critical refracted shear waves propagating along a fluid‐filled borehole. Using integration by parts, we asymptotically expand the vertical branch‐cut integral of shear waves in an infinite series related to each order of the derivative of the response function of the formation. It is proved that the vertical branch‐cut integral of shear waves at large offsets consists mainly of the contribution of the second asymptotic series, which is related to the first derivative of the response function of the formation at the shear branch point. Using the asymptotic expansion, we develop a simplified amplitude expression for shear waves, and the resonant frequency formula. The validity of the resonance frequencies obtained by the resonant frequency formula is verified numerically by comparison with the corresponding frequencies of the numerical integral results. We also give a rational explanation for the phenomenon of two peaks appearing within each resonant peak zone: i.e. that these are the contributions of the constructive interference of the shear waves and the mode poles.
The trajectory of minor stroke recovery for men and their female spousal caregivers: literature review
Authors: Green Theresa L. , King Kathryn M. 
Published: May 2007

Abstract Title. The trajectory of minor stroke recovery for men and their female spousal caregivers: literature review Aim.  This paper is a report of a narrative review to examine the current state of knowledge regarding the impact of minor stroke on male patients and their female spousal caregivers’ recovery trajectory and quality of life.Background.  Minor stroke survivors are often discharged early in the recovery process. The perception of the healthcare community that these patients and their female spousal caregivers will experience an uneventful recovery may lead to inadequate preparation for the postdischarge period.Methods.  A range of databases was searched to identify papers addressing ‘minor stroke’, ‘transitions’, ‘quality of life’, ‘chronic disease’, ‘caregivers’ and ‘spouse caregivers’, including AARP Ageline, AMED, CINAHL, Evidence Based Medicine Reviews, MEDLINE and PsychInfo. Papers published in English from 1990 to December 2006 were included. Thirty‐four papers were in the final data set.Results.  Minor stroke survivors and their female spousal caregivers may experience major challenges in adaptations postdischarge. The trajectory of minor stroke recovery may necessitate a re‐evaluation of life plans, rethinking of priorities and integration of resulting disabilities into current and emerging life situations for both stroke survivors and their female spousal caregivers. In many cases these adaptations are compounded by transitions associated with the normal ageing process.Conclusion.  While there is extensive literature on stroke recovery and the role of caregivers in general, there is little available describing the recovery of minor stroke survivors in relation to the normal ageing process. Further research is needed examining recovery from a transitional perspective, to support nurses and other health professionals discharge planning.
Driven by the West Wind Drift? A synthesis of southern temperate marine biogeography, with new directions for dispersalism
Authors: Waters Jonathan M. 
Published: May 2007

AbstractAim Twentieth century biogeographers developed intriguing hypotheses involving West Wind Drift dispersal of Southern Hemisphere biota, but such models were largely abandoned in favour of vicariance following the development of plate tectonic theory. Here I present a synthesis of southern temperate marine biogeography, and suggest some new directions for phylogeographic research.Location The southern continents, formerly contiguous components of Gondwana, are now linked only by ocean currents driven by the West Wind Drift.Methods While vicariance theory certainly facilitates the development of testable hypotheses, it does not necessarily follow that vicariance explains much of contemporary southern marine biogeography. To overcome the limitations of narratives that simplyassumevicariance or dispersal, it is essential for analyses to test biogeographic hypotheses by incorporating genetic, ecological and geological data.Results Recent molecular studies have provided strong evidence for dispersal, but relatively little evidence for the biogeographic role of plate tectonics in distributing southern marine taxa. Despite confident panbiogeographic claims to the contrary, molecular and ecological studies of buoyant macroalgae, such asMacrocystis, indicate that dispersal predominates. Ironically, some of the better supported evidence for marine vicariance in southern waters has little or nothing to do with plate tectonics. Rather, it involves far more localized and recent vicariant models, such as the isolating effect of the Bassian Isthmus during Pleistocene low sea‐level stands (Nerita).Main conclusions Recent phylogeographic studies of southern marine taxa (e.g.DilomaandParvulastra) imply that passive rafting cannot be ignored as an important mechanism of long‐distance dispersal. I outline a new direction for southern hemisphere phylogeography, involving genetic analyses of bull‐kelp (Durvillaea) and its associated holdfast invertebrate communities.