bluuebunny/crossref_metadata_2025 huggingface dataset:
Complexation of the 2, 4, 6‐Triallyloxy‐1, 3, 5‐triazine with Copper(I, II) Chlorides. Syntheses and Crystal Structures of [CuCl2·2C3N3(OC3H5)3], [Cu7Cl8·2C3N3(OC3H5)3], and [Cu8Cl8·2C3N3(OC3H5)3]·2C2H5OH
Authors: Goreshnik E. A. , Ciunik L. Z. , Gorelenko Yu. K. , Mys'kiv M. G.
Published: December 2004

Interaction of copper(II) chloride with 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine leads to formation of copper(II) complex [CuCl2·2C3N3(OC3H5)3] (I). Electrochemical reduction of I produces the mixed‐valence CuI, II π, σ‐complex of [Cu7Cl8·2C3N3(OC3H5)3] (II). Final reduction produces [Cu8Cl8·2C3N3(OC3H5)3]·2C2H5OH copper(I) π‐complex (III). Low‐temperature X‐ray structure investigation of all three compounds has been performed: I: space group P1¯, a = 8.9565(6), b = 9.0114(6), c = 9.7291(7) Å, α = 64.873(7), β = 80.661(6), γ = 89.131(6)°, V = 700.2(2) Å3, Z = 1, R = 0.0302 for 2893 reflections. II: space group P1¯, a = 11.698(2), b = 11.162(1), c = 8.106(1) Å, α = 93.635(9), β = 84.24(1), γ = 89.395(8)°, V = 962.0(5) Å3, Z = 1, R = 0.0465 for 6111 reflections. III: space group P1¯, a = 8.7853(9), b = 10.3602(9), c = 12.851(1) Å, α = 99.351(8), β = 105.516(9), γ = 89.395(8), V = 1111.4(4) Å3, Z = 1, R = 0.0454 for 4470 reflections. Structure of I contains isolated [CuCl2·2C3N3(OC3H5)3] units. The isolated fragment of I fulfils in the structure of II bridging function connecting two hexagonal prismatic‐like cores Cu6Cl6, whereas isolated Cu6Cl6(CuCl)2 prismatic derivative appears in III. Coordination behaviour of the 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine moiety is different in all the compounds. In I ligand moiety binds to the only copper(II) atom through the nitrogen atom of the triazine ring. In II ligand is coordinated to the CuII‐atom through the N atom and to two CuI ones through the two allylic groups. In III all allylic groups and nitrogen atom are coordinated by four metal centers. The presence of three allyl arms promotes an acting in II and III structures the bridging function of the ligand moiety. On the other hand, space separation of allyl groups enables a formation of large complicated inorganic clusters.
EPR‐spektroskopische Charakterisierung (X‐, Q‐Band) monomerer AgII‐ und AuII‐Komplexe der Thiakronenether [12]anS4, [16]anS4, [18]anS6 und [27]anS9
Authors: Kampf Michael , Griebel Jan , Kirmse Reinhard
Published: December 2004

Die Reaktion der AgI‐Komplexe der Thiakronenether [12]anS4, [16]anS4, [18]anS6 und [27]anS9 mit konzentrierter H2SO4 wie auch die Umsetzung von [AuIIICl4]‐ mit [18]anS6 und [27]anS9 führt zur Bildung labiler AgII‐ (4d9, 107, 109Ag: I=1/2) bzw. AuII‐ (5d9, 197Au: I=3/2) Thiakronenetherkomplexe, die im X‐ und Q‐Band EPR‐spektroskopisch charakterisiert wurden. Früher berichtete EPR‐Parameter für [AgII([12]anS4)]2+ und [AgII([18]anS6)]2+ werden korrigiert. Eine Analyse der Spindichteverteilung weist nur ca. 20 bis 25 % am Ag‐ bzw. Au‐Atom aus; der größte Teil der Spindichte befindet sich an den S‐Donoratomen der Thiakronenether. Das aufgrund der ausgeprägten Delokalisierung der Spindichte sicher sehr stark verringerte AgI/AgII‐Redoxpotential wird als wesentlicher Grund für die verhältnismäßig leichte Zugänglichkeit der AgII‐Thiakronenetherkomplexe erachtet.
nido‐Undecaboranes and ‐borates of the Type B11H13L and B11H12L‐
Authors: Dirk Wolfgang , Paetzold Peter , Hu Chunhua , Volkov Oleg
Published: December 2004

The Lewis base SMe2 in 7‐B11H13(SMe2) (1a) can be replaced by the amines L = NH2(CH2tBu), NH2Cy, NH2Ph, NH2(4‐C6H4Me), py, chinoline or the phosphanes L = PPh3, PMePh2, yielding 7‐B11H13L (1b‐i). The borane 1a can be deprotonated by certain amines, alkanides, or hydrides to give the anion 7‐B11H12(SMe2)‐ (2a). Replacing the base SMe2 in the anion 2a by weak bases gives B11H12L‐ (L = PPh3, MeCN; 2h, j). Upon reaction of 1a with the amine NH2(CH2tBu) in the ratio 1:2, a deprotonation and the substitution of SMe2 by the amine are observed, 7‐B11H12[NH2(CH2tBu)]‐ (2b) being formed. At 170 °C, the 7‐isomers 1b, f are isomerized into a mixture of the corresponding 1‐ and 2‐isomers (1b′, f′ and 1b″, f″, respectively).
Unusual Oligonuclear Copper(II) Complexes based on a Bis( tridentate) Compartmental Pyrazolate Ligand
Authors: Ackermann Jens , Meyer Franc , Pritzkow Hans
Published: December 2004

Some unusual oligonuclear copper(II) complexes with a bis(tridentate) pyrazolate‐based ligand that is composed of two diethylentriame‐type coordination compartments have been structurally characterized. In [(LCu2)2(CO3)(H2O)2(ClO4)](ClO4)3 (1), CO2 has been taken up and two {LCu2} subunits are spanned by both a μ3‐μ3‐κO:κO′:κO″‐bridging carbonate as well as by a μ3‐κO:κO′:κO″‐bridging perchlorate. The latter is a rare structural motif in coordination chemistry. In one experiment, a different complex [(LCu2(OH))2Cu2(OH)4](BF4)4 (2) has been serendipitiously obtained. One Cu atom of each {LCu2} subunit of 2 together with two further copper ions forms a pyrazolate‐appanded {Cu4(OH)4} cube.
Synthesis and Structural Characterization of a Novel Type of Heteropolyanion: [Sb4Mo12(OH)6O48]10‐
Authors: Drewes Daniel , Vollmer Guido , Krebs Bernt
Published: December 2004

A novel antimony substituted polyoxomolybdate has been synthesized and characterized by X‐ray structure analysis, energy dispersive X‐ray fluorescence analysis, Raman and IR spectroscopy. The [Sb4Mo12(OH)6O48]10‐ anion exhibits a central Sb4(OH)6O14 core where all SbV atoms are coordinated octahedrally by six oxygen atoms. It represents a novel type of heteropolyanion with no known analogous structure in literature.
Die Kristallstrukturen von (Ph4P)2[HfCl6]·2CH2Cl2 und (Ph4P)2[Hf2Cl10]·CH2Cl2
Authors: Neumüller Bernhard , Dehnicke Kurt
Published: December 2004

Crystal Structures of (Ph4P)2[HfCl6]·2CH2Cl2 and (Ph4P)2[Hf2Cl10]·CH2Cl2

Colourless single crystals of (Ph4P)2[HfCl6]·2CH2Cl2 (1) and (Ph4P)2[Hf2Cl10]·CH2Cl2 (2) were obtained from hafniumtetrachloride and tetraphenylphosphonium chloride in dichloromethane solution, using the corresponding stoichiometry of the educts. Both compounds were characterized by X‐ray structure determinations. 1: Space group P1¯, Z = 1, lattice dimensions at 193 K: a = 1018.3(1), b = 1121.0(1), c = 1240.1(1) pm, α = 70.55(1)°, β = 81.38(1)°, γ = 80.02(1)°, R1 = 0.0374.

2: Space group P1¯, Z = 1, lattice dimensions at 193 K: a = 1124.4(1), b = 1141.9(1), c = 1281.4(1) pm, α = 63.80(1)°, β = 68.15(1)°, γ = 86.33(1)°, R1 = 0.0208.
UDP‐glucose and UDP‐galactose concentrations in cultured skin fibroblasts of patients with classical galactosaemia
Authors: Keevill N. J. , Holton J. B. , Allen J. T.
Published: December 2004

A very clear‐cut reduction in UDP‐galactose (UDPGal) levels in erythrocytes, skin fibroblasts and liver of patients with classical galactosaemia has been reported. As UDPGal is the galactosyl donor in glycoprotein and glycolipid synthesis, it has been suggested that an abnormality in these complex compounds may be the cause of some of the long‐term complications of the disease. More recent work on erythrocytes, employing mainly HPLC rather than the enzyme methods used to measure UDPGal originally, casts doubt on the hypothesis because, although some reduction was still found, there was a large overlap between galactosaemic and normal distributions. We have reproduced the experiments on cultured skin fibroblasts at confluency, but measuring UDPGal and UDP‐glucose (UDPGlc) by HPLC. There was no reduction in UDPGal levels in galactosaemic compared to control cell lines. The existence of a biologically significant depletion of UDPGal in galactosaemia remains in doubt.
Ligand Binding Characteristics of the Human Serotonin1A Receptor Heterologously Expressed in CHO Cells
Authors: Kalipatnapu Shanti , Pucadyil Thomas J. , Harikumar Kaleeckal G. , Chattopadhyay Amitabha
Published: December 2004

The serotonin1A (5-HT1A) receptors are important members of the superfamily of seven transmembrane domain G-protein coupled receptors. They appear to be involved in various behavioral, cognitive and developmental functions. Mammalian cells in culture heterologously expressing membrane receptors represent convenient systems to address problems in receptor biology. We report here the pharmacological characterization of one of the first isolated clones of CHO cells stably expressing the human 5-HT1A receptor using the selective agonist 8-OH-DPAT and antagonist p-MPPF. In addition, we demonstrate that agonist and antagonist binding to the receptor exhibit differential sensitivity to the non-hydrolyzable GTP analogue, GTP-γ-S, as was observed earlier with the native receptor from bovine hippocampus. These results show that the human 5-HT1A receptor expressed in CHO cells displays characteristic features found in the native receptor isolated from bovine hippocampus and promises to be a potentially useful system for future studies of the receptor.
Bioenergetics of Yarrowia lipolytica Cells Grown at Alkaline Conditions
Authors: Zvyagilskaya Renata A. , Parkhomenko Olga A. , Gordeeva Anna V. , Deryabina Yuliya I. , Persson Bengt L.
Published: December 2004

Energy status of the novel alkalitolerant Yarrowia lipolytica yeast strain grown at alkaline conditions (pH 9.7) was examined. Cells grown under such severe conditions were found to preserve high respiratory activity. The oxidative phosphorylation system dominated in the energy budget of the cell. A procedure was specially design to isolate tightly coupled mitochondria from yeast cells grown at alkaline conditions. The isolated mitochondrial preparations met known criteria of physiological intactness, as inferred from their ability to maintain distinctive state 4–3 respiration transition upon addition of ADP, high respiratory rates, good respiratory control values, and ADP/O ratios close to the theoretically expected maxima for the substrates used.
Decomposition of organic chemical components in relation to nitrogen dynamics in leaf litter of 14 tree species in a cool temperate forest
Authors: Osono Takashi , Takeda Hiroshi
Published: December 2004

Decomposition of lignin, holocellulose, polyphenols and soluble carbohydrates was investigated in relation to nitrogen (N) dynamics in leaf litter of 14 tree species. The influence of organic chemical components and N on litter mass loss rate was then evaluated for 14 litter types. The study was carried out over a 3‐year period on upper and lower parts of a forest slope in a cool temperate forest in Japan. The decomposition processes were divided into early and late phases based on N immobilization and mobilization. Mass loss rate of whole litter and organic chemical components was similar for the upper and lower sites. Litter mass loss was faster in the immobilization phase than in the mobilization phase in each of 14 litter types, which was ascribed to the decreased mass loss of holocellulose, polyphenols and soluble carbohydrates in the mobilization phase as compared to the immobilization phase. Mass loss rate of lignin was not different between the phases. Litter mass loss rate in the immobilization and mobilization phases was negatively correlated to lignin content and positively correlated to contents of polyphenols and soluble carbohydrates at the start of these phases, but was not correlated to holocellulose and N contents in either phase.
Geographic variation in nut size of Castanopsis species in Japan
Authors: Yamada Hiroo , Miyaura Tomiyasu
Published: December 2004

The environmental conditions affecting the geographic variation in nut size of the Castanopsis species in Japan were examined. The mother trees having a relatively large nut tended to dominate in the geographically marginal area of the distribution range in Japan, i.e. the Japan Sea, Kanto, and Ryukyu areas, whereas in the central area, i.e. the Pacific area, mother trees having a relatively small nut occurred. We attempted an adaptive explanation, proposing that mother trees with large nuts have higher inclusive fitness than those with small nuts in unfavorable habitats. The Japan Sea area features large amounts of snow fall and low temperatures. The Ryukyu area is insular and is characterized by high temperatures. Within the Pacific area, mother trees with relatively large nuts were abundant at both higher and lower parts of the altitudinal range. We infer that environmental conditions in marginal areas, in terms of both horizontal and vertical distribution, favor mother trees having large nuts. However, in the marginal Kanto area, the cause of the absence of mother trees having relatively small nuts was independent of the environmental conditions. The geographic variation in nut size of Castanopsis species is not always explained by environmental factors.
Factors influencing the distribution of two co‐occurring dwarf bamboo species (Sasa kurilensis and S. senanensis) in a conifer‐broadleaved mixed stand in northern Hokkaido
Authors: Noguchi Mahoko , Yoshida Toshiya
Published: December 2004

We have investigated the factors influencing the distribution of co‐occurring two dwarf bamboo species, Sasa kurilensis (Ruprecht) Makino et Shibata and S. senanensis (Franchet et Savatier) Rehder, within a conifer‐broadleaved mixed stand managed with selection cutting in northern Japan. We first sought the possible determinant factors (physical environment and overstory conditions based on 30 years’ tree census data) deciding the dominant species in the plots (168 3.14m2 area). We then examined the effects of these factors on the culm density and height of the dominant species. Linear discriminant analysis indicated that physical environmental conditions are important in determining the distribution; S. kurilensis tended to dominate plots with steep slope, convex shape and deep snow in early spring. Multiple regression analyses showed that culm density and height decreased significantly on steep slopes for both species. Also, the sum of the basal area (BA) of surrounding conifers (7.5 m radius around the plot), as well as the change in BA over the previous 30 years, had a negative influence on the culm height of both species. A reduction in overstory trees, caused by natural or artificial canopy disturbances, would increase the dwarf bamboo biomass. The effects of physical environment and overstory conditions, working through the dominance of the two dwarf bamboo species, should be taken into account in understanding the dynamics of natural forests in this region.
The choice of oviposition site and the effects of density and oviposition timing on survivorship in Rana japonica
Authors: Matsushima Noe , Kawata Masakado
Published: December 2004

In species that lack parental care and whose larvae are restricted to a given space throughout development, choice of egg‐laying or reproductive sites often greatly influences fitness. Furthermore, reproductive success of individuals may be affected not only by conditions of the breeding area but also by the time when they start to breed, because intraspecific variation in the timing of breeding may result in asymmetric competition between larvae. We addressed these issues in an experimental and field study of the Japanese brown frog, Rana japonica. We tested whether the survival success of larvae decreased with an increase in the number of deposited egg masses and with a greater delay in oviposition. We found that the number of egg masses and timing of oviposition together significantly predicted larval survival per clutch. Moreover, we observed the natural oviposition of R. japonica to examine the prediction that if the density of larvae and the timing of oviposition affect survivorship of larvae, R. japonica will avoid depositing eggs in pools in which egg masses have already been deposited. We found that for small pools only, R. japonica tended to favor oviposition at unoccupied pools (those lacking egg masses and larvae) in the spawning season. For large pools, however, adults favored those already occupied by egg masses in the spawning period. The density of egg masses and tadpoles or the timing of oviposition may have less effect on spawning or the survival of tadpoles in large pools than in small pools.
Home range and habitat use by the sableMartes zibellina brachyurain a Japanese cool‐temperate mixed forest
Authors: Miyoshi Kazuki , Higashi Seigo
Published: December 2004

Home range and habitat use of the sableMartes zibellina brachyurawere studied in a cool‐temperate mixed forest in northernmost Japan. In both sexes, some sables showed a wide range of migration without establishing home ranges and the others had home ranges of 0.50–1.78 km2(mean: 1.12±SD 0.495 km2,n=6) which were not significantly correlated with body weight or age. The analysis of canine tooth annuli revealed that the maximum age was 5.5 years. The home ranges of some sables overlapped so extensively that the home ranges and even the core areas did not appear exclusive to other sables. We determined resting sites and foraging routes in snow in winter. Comparison of vegetation at the resting sites and foraging routes with habitat availability suggested that the sables preferred resting in dense‐tree forests with many tree species and debris probably in order to avoid predators (red foxes) and strong wind and foraging in forests of climax succession which are usually rich in their prey such as voles and mice.
Genetic structure ofMiscanthus sinensisssp.condensatus(Poaceae) on Miyake Island: implications for revegetation of volcanically devastated sites
Authors: Iwata Hiroyoshi , Kamijo Takashi , Tsumura Yoshihiko
Published: December 2004

We investigated the genetic structure ofMiscanthus sinensisssp.condensatuson Miyake Island, which was devastated by a volcanic eruption in 2000, by amplified fragment length polymorphisms (AFLPs) and polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) for chloroplast DNA (cpDNA) variation, to develop recommendations for the revegetation of devastated sites. Genetic differentiation among populations was significant, and five populations were classified into three regional groups. The aspect ratios of leaf‐blades varied significantly among populations, but both geographical proximity and morphological similarities did not precisely reflect genetic similarities. In the airport population, we found a rare haplotype that may have been transmitted from outside the island. These findings will assist the revegetation of the island.
The Mosbeck Site: a Paleoenvironmental Interpretation of the Late Quaternary History of Lake Agassiz Based on Fossil Insect and Mollusk Remains
Authors: Ashworth Allan C. , Clayton Lee , Bickley William B.
Published: December 2004

The Mosbeck Site is in the southern part of the Lake Agassiz basin in northwestern Minnesota. The stratigraphic section at the site consists of seven lithologic units, which are from bottom to top (A) unsorted, pebbly, sandy, silty clay, (B) coarse gravel, (C) silty sand, (D) peat, (E) fine sand, (F) interbedded sand and gravel, and (G) unbedded dirty gravel. The lower few centimeters of unit E are unoxidized and contain black spruce and tamarack driftwood, which has been radiocarbon dated at 9940 ± 160 BP (I-3880). Units C-E contain numerous, well-preserved insect and mollusk remains. These fossils have been compared with modern species, and at least 76 insect and 15 mollusk taxa are present. Assuming that their ecological tolerances have changed little in the past 10,000 years, they provide valuable information about the environment of Lake Agassiz. Few of the insects are now found in the region, indicating that the environment has changed. With few exceptions the species present indicate that the climate and vegetation at the time were similar to the present-day climate and vegetation of southeastern Manitoba.

The lithology and faunal contents of the sediment are interpreted as follows. Unit A is Late Wisconsinan glacial sediment. Unit B is a lag concentrate formed by wave action during a regressive phase of Lake Agassiz. Unit C is the sediment of a small body of water that formed when the level of Lake Agassiz had dropped below the site. The banks were covered with a spruce forest. Open water gave way to swampy conditions, and unit D was formed. Both units C and D were deposited during the low-water Moorhead Phase of Lake Agassiz. Units E and F are shoreline sediment deposited as the lake level rose, drowning the vegetation. Unit G is modern ditch spoil.
Late Quaternary Vegetation Development in South-Central Illinois
Authors: Grüger Eberhard
Published: December 2004

Pollen and macrofossil evidence for the nature of the vegetation during glacial and interglacial periods in the regions south of the Wisconsinan ice margin is still very scarce. Modern opinions concerning these problems are therefore predominantly derived from geological evidence only or are extrapolated from pollen studies of late Wisconsinan deposits. Now for the first time pollen and macrofossil analyses are available from south-central Illinois covering the Holocene, the entire Wisconsinan, and most probably also Sangamonian and late Illinoian time. The cores studied came from three lakes, which originated as kettle holes in glacial drift of Illinoian age near Vandalia, Fayette County. The Wisconsinan ice sheet approached the sites from the the north to within about 60 km distance only.

One of the profiles (Pittsburg Basin) probably reaches back to the late Illinoian (zone 1), which was characterized by forests with muchPicea. Zone 2, most likely of Sangamonian age, represents a period of species-rich deciduous forests, which must have been similar to the ones that thrive today south and southeast of the prairie peninsula. During the entire Wisconsinan (14C dates ranging from 38,000 to 21,000 BP) thermophilous deciduous trees likeQuercus, Carya, andUlmusoccurred in the region, although temporarily accompanied by tree genera with a more northerly modern distribution, such asPicea, which entered and then left south-central Illinois during the Woodfordian. Thus it is evident that arctic climatic conditions did not prevail in the lowlands of south-central Illinois (about 38°30′ lat) during the Wisconsinan, even at the time of the maximum glaciation, the Woodfordian. The Wisconsinan was, however, not a period of continuous forest. The pollen assemblages of zone 3 (Altonian) indicate prairie with stands of trees, and in zone 4 the relatively abundantArtemisiapollen indicates the existence of open vegetation and stands of deciduous trees,Picea, andPinus. True tundra may have existed north of the sites, but if so its pollen rain apparently is marked by pollen from nearby stands of trees. After the disappearance ofPinusandPiceaat about 14,000 BP (estimated!), there developed a mosaic of prairies and stands ofQuercus, Carya, and other deciduous tree genera (zone 5). This type of vegetation persisted until it was destroyed by cultivation during the 19th and 20th century. Major vegetational changes are not indicated in the pollen diagram for the late Wisconsinan and the Holocene.

The dating of zones 1 and 2 is problematical because the sediments are beyond the14C range and because of the lack of stratigraphic evidence. The zones dated as Illinoian and Sangamonian could also represent just a Wisconsinan stadial and interstadial. This possibility, however, seems to be contradicted by the late glacial and interglacial character of the forest vegetation of that time.
Past and Present Glaciological Responses to Climate in Eastern Baffin Island
Authors: Andrews J.T. , Barry R.G. , Bradley R.S. , Miller G.H. , Williams L.D.
Published: December 2004

Much of Baffin Island is close to the modern glaciation limit and climatic changes within the last decade are already being reflected in snow cover extent. Statistical analysis of glacierized and ice-free corries indicates that changes in direct solar radiation due to astronomical factors are inadequate to account for glacierization of those at present ice-free. These and other sources of evidence demonstrate the need for augmented winter snowfall in order to increase the extent of glacierization. The pattern of glacial history in this area is for maximum ice extent during the early glacial phase (>68,000, <137,000 BP), followed by a reduction in ice volume during the cold pleniglacial (>24,000, < 68,000 BP) and then a limited late glacial advance (the Cockburn Stade, ca. 8,000 BP) due to increased precipitation. The Barnes Ice Cap did not disappear in the Holocene as it did in the last interglacial. The area is highly suitable for long-term monitoring of climatic change and glacial response.
Insolation Regime of Interglacials
Authors: Kukla George J. , Kukla Helena J.
Published: December 2004

Seasonal changes in the extent of snow cover and pack-ice were analysed in the satellite-derived maps of the Northern Hemisphere obtained during the last 5 yr. Two intervals were studied in detail: summer 1968 to summer 1969 and summer 1971 to summer 1972. These studies demonstrate that the variation in ground albedo as a result of changing snow and ice cover affects the Earth's energy budget to a far greater degree than any possible extraterrestrial mechanism could do on such a short time scale. However, the rapid expansion of snow cover between late September and November suggests possible feed-back process which could be speeded up or slowed down by minute changes in energy and moisture budget at the snow accretion area. These changes may be of any origin, natural or artificial, and on the time scales ranging from days to millenia.

In this context, the close correspondence between the radiometrically dated gross climate changes within the past 150,000 yr and between the curve showing the rate of change in winter insolation for the middle latitudes of the Northern Hemisphere is conspicuous. The periodicity of about 20,000 yr is involved.

An insolation chronology is introduced here, which is based entirely on astronomic factors (on the so called Milankovitch mechanism of Earth orbital elements). It is independent of any geologic or geochronologic dating systems. Two alternating units comprise the insolation chronology.The positive insolation regime (PIR)is an episode defined by progressively increasing winter irradiation in the Northern Hemisphere, whereas thenegative insolation regime (NIR)is an episode of progressively decreasing winter irradiation. ThePIRclosely correlates with the generally warm intervals such as interglacials and temperate interstadials, theNIRwith generally cold intervals. This basic pattern interferes with short-term oscillations which may retard or advance the climate response on the scale of centuries.

It is observed that the positive insolation regime designated asPIR110, which started at 11,000 YBP, has ended recently. The new negative insolation regime,NIR 0/ + 8, will last for the next 8000 yr. Inasmuch within the last radiometrically dated 150,000 yr noNIRis known to correlate with generally warm interval, the prognosis is for a long-lasting global cooling more severe than any experienced hitherto by civilized mankind.
Fire in the Virgin Forests of the Boundary Waters Canoe Area, Minnesota
Authors: Heinselman Miron L.
Published: December 2004

Fire largely determined the composition and structure of the presettlement vegetation of the Boundary Waters Canoe Area as well as the vegetation mosaic on the landscape and the habitat patterns for wildlife. It also influenced nutrient cycles, and energy pathways, and helped maintain the diversity, productivity, and long-term stability of the ecosystem. Thus the whole ecosystem was fire-dependent.

At least some overstory elements in virtually all forest stands still date from regeneration that followed one or more fires since 1595 A.D. The average interval between significant fire years was about 4 yr in presettlement times, but shortened to 2 yr from 1868 to 1910 during settlement. However, 83% of the area burned before the beginning of suppression programs resulted from just nine fire periods: 1894, 1875, 1863–1964, 1824, 1801, 1755–1959, 1727, 1692, 1681. The average interval between these major fire years was 26 yr. Most present virgin forests date from regeneration that followed fires in these years. Significant areas were also regenerated by fires in 1903, 1910, 1936, and 1971. Most major fire years occurred during prolonged summer droughts of subcontinental extent, such as those of 1864, 1910, and 1936. Many fires were man-caused, but lightning ignitions were also common. Lightning alone is probably a sufficient source of ignitions to guarantee that older stands burned before attaining climax. Dry matter accumulations, spruce budworm outbreaks, blowdowns, and other interactions related to time since fire increase the probability that old stands will burn. Vegetation patterns on the landscape were influenced by such natural firebreaks as lakes, streams, wetlands, and moist slopes. Red and white pine are most common on islands, and to the east, northeast, or southeast of such firebreaks. Jack pine, aspen-birch, and sprout hardwood forests are most common on large uplands distant from or west of such firebreaks.

A Natural Fire Rotation of about 100 yr prevailed in presettlement times, but many red and white pine stands remained largely intact for 150–350 yr, and some jack pine and aspen-birch forests probably burned at intervals of 50 yr or less. There is paleoecological evidence that fire was an ecosystem factor before European man arrived, and even before early man migrated to North America. Probably few areas ever attained the postulated fir-spruce-cedar-birch climax in postglacial times. To understand the dynamics of fire-dependent ecosystems fire must be studied as an integral part of the system. The search for stable communities that might develop without fire is futile and avoids the real challenge of understanding nature on her own terms.

To restore the natural ecosystem of the Canoe Area fire should soon be reintroduced through a program of prescribed fires and monitored lightning fires. Failing this, major unnatural, perhaps unpredictable, changes in the ecosystem will occur.
A History of Fire and Vegetation in Northeastern Minnesota as Recorded in Lake Sediments
Authors: Swain Albert M.
Published: December 2004

The record of charcoal in lake sediments indicates that fire has always been an important ecological factor in the forest history of northeastern Minnesota. The annually laminated sediments of Lake of the Clouds permit precise dating of the charcoal peaks and record the changes in the influx of various pollen types. A detailed record of the past 1000 yr shows that the average frequency of fire is approximately 60–70 yr, with a range of about 20–100 yr. The amount of charcoal in sediments dating between 1000-500 y.a. is consistently higher than that for the last 500 yr, although the fire frequency for the two periods was not appreciably different. Pollen analysis shows no change or only short-term changes in the percentages of major pollen types following charcoal peaks.
The Importance of Fire as a Natural Ecological Factor in Itasca State Park, Minnesota
Authors: Frissell Sidney S.
Published: December 2004

During the period between 1650 least 32 fires occurred in Itasca and 1922 at State Park. Twenty-one of these fires were of major consequence. A fire occurred on the average of every 8.8 yr with “major” fires every 10.3 yr. Any specific location in the park was affected by fire about every 22 yr.

Individual burns varied in size from 580 acres to approximately 31,960 acres (99% of the park). Sixteen of the 21 “major” fires resulted in the regeneration of pine forests.
Fire-Dependent Forests in the Northern Rocky Mountains
Authors: Habeck James R. , Mutch Robert W.
Published: December 2004

One objective of wilderness and parkland fire-ecology research is to describe the relationships between fire and unmanaged ecosystems, so that strategies can be determined that will provide a more nearly natural incidence of fire. More than 50 yr of efforts directed toward exclusion of wildland fires in the Northern Rocky Mountains (western Montana and northern Idaho) have resulted in a definite and observable impact on the forest ecosystems in this region. Fire-ecology investigations in Glacier National Park and the Selway-Bitterroot Wilderness have helped to reveal the nature of this impact and to provide a better understanding of the natural role of fire within these coniferous ecosystems. Such areas provide a unique opportunity to study and test approaches designed to perpetuate unmodified ecosystems. However, we still don't understand all of the long-term consequences of fire control in those forest communities that have evolved fire-dependent characteristics.
The Ecological Role of Fire in the Jackson Hole area, Northwestern Wyoming
Authors: Loope Lloyd L. , Gruell George E.
Published: December 2004

Fire-history investigations in the Jackson Hole area of northwestern Wyoming reveal that most current stands of aspen and lodgepole pine regenerated following extensive fires between 1840 and 1890 and that widespread fires occurred in the 1600s and 1700s. White man's major effect on the fire incidence has been the successful suppression during the past 30–80 yr. Successional changes in the absence of fire include the deterioration of aspen stands, massive invasions of subalpine fir in lodgepole pine stands, great increase in conifer cover, heavy fuel buildups in lodgepole pine and Douglas fir stands, and increase in sagebrush and other shrubs. Steps are being taken, starting in 1972, to allow fire to play a more natural role in Grand Teton and Yellowstone National Parks. Teton National Forest plans experimental prescribed burning to determine whether fire can stimulate successful aspen regeneration in the presence of large numbers of wintering elk.
Spectral Analysis of Late Pleistocene-Holocene Sediments
Authors: Pisias Nicklas G. , Dauphin J.Paul , Sancetta Constance
Published: December 2004

Spectral analysis of deep-sea sediments indicates that the fluctuations in compositional parameters are not random fluctuations with time. Spectra show significant peaks representing periodicities in the data of 380, 1300, and 2600 years. Two of these periods are similar to periods reported in 14C fluctuations. Analysis of a paleotemperature curve from the North Atlantic shows that the characteristics of the fluctuations within interglacial and glacial stages of the climate are similar, and that the spectrum has a significant peak at 2600 years.
Time-Transgressive Deglacial Retreat of Polar Waters from the North Atlantic
Authors: Ruddiman W.F. , McIntyre A.
Published: December 2004

A 9300 yr-old zone of disseminated volcanic ash in North Atlantic sediments between 45° N and 65° N provides a time-synchronous reference layer against which we have compared the stratigraphic level of deglacial warming of ocean surface waters. In the Atlantic north of 45° N the most prominent feature of this warming is the replacement of low-carbonate glacial marine sediment containing only a single species of polar Foraminifera by calcareous oozes containing a diverse temperate fauna and flora. The local terminations of glacial conditions marked by this change are not synchronous at these latitudes, but range from 13,500 yr B.P. or older in the southeast near Great Britain to 6,500 yr B.P. or younger in the northwest near Greenland. Regionally, these local warmings trace the progressive westward and northward retreat of polar water from the North Atlantic. Since the withdrawal of polar water from the North Atlantic coincides with the northward shrinkage of temperate-latitude continental ice sheets, it is the best oceanic analog to continental deglaciation.

Faunal, floral, lithologic, and isotopic parameters showing evidence for a sudden deglacial warming may not be time-synchronous; those parameters are subject to a range of environmental controls and may thus respond differently to the causal mechanism for global warming.
Bottom Water and Benthonic Foraminifera in the North Atlantic—Glacial-Interglacial Contrasts
Authors: Streeter S.Stephen
Published: December 2004

Today, below 2500 m, benthonic foraminiferal faunas in the North Atlantic are dominated by a few species. Faunal composition changes slowly with increasing depth and decreasing temperature. Surface sediment and down-core counts of benthonic foraminifera reported by Phleger, Parker, and Peirson (1953) in the reports of the Swedish Deep-Sea Expedition have been supplemented by additional bottom sediment and piston core samples. Present-day benthonic foraminiferal assemblages from the deeper portions of the North Atlantic appear to be controlled more by the distribution of bottom water types than by bathymetry. In most piston cores, the assemblages vary greatly during the last 150,000 yr, suggesting depression and elevation of faunas at the core site through a depth range of several hundred meters. This would indicate that bottom water characteristics have shifted back and forth in this interval of time and, therefore, that bottom circulation partakes in the well-documented shifts recorded for surface waters of the North Atlantic. It appears that dense water, similar to present-day North Atlantic Deep Water, was produced over a wide area north of 45° N during cooler intervals and that it spread widely at depth.
Helium-Uranium Dating of Corals from Middle Pleistocene Barbados Reef Tracts
Authors: Bender Michael L. , Taylor F.T. , Matthews R.K.
Published: December 2004

By He-U dating of corals from elevated Pleistocene reef tracts on Barbados, we have extended back to the Middle Pleistocene the high sea stand chronology previously deduced by Th230-U dating. Six samples from the first major reef tract complex older than the 200,000-yr complex gave ages of 350,000 ± 25,000 yr B.P. Two corals from the crest of Second High Cliff, an unusually large escarpment occurring approximately midway in the terrace sequence, gave concordant ages of 480,000 and 500,000 yr. Unrecrystallized corals from older reefs gave ages ranging back to 650,000 yr.

The results date episodes of high sea stands at 350,000 and 500,000 yr B.P.
Itkillik Glaciation in the Brooks Range, Northern Alaska
Authors: Hamilton Thomas D. , Porter Stephen C.
Published: December 2004

During the Itkillik Glaciation the Brooks Range supported an extensive mountain-glacier complex that extended for 750 km between 141° and 158°W longitude. Individual ice streams and piedmont lobes flowed as much as 50 km beyond the north and south margins of the range. Glaciers in the southern Brooks Range were longer than those farther north because of a southerly precipitation source, whereas those in the central and eastern part of the range were larger than glaciers at the extremities of the mountain system because of higher and more-extensive accumulation areas. Glacier equilibrium-line altitudes (ELAs) at the time of greatest advance were depressed 600 ± 100 m below present levels, whereas during a less-extensive late-glacial readvance (Alapah Mountain) ELA depression was about 300 ± 30 m. Radiocarbon dates indicate that Itkillik drift correlates with Late Wisconsin drift along the southern margin of the Laurentide Ice Sheet and with drift of Cordilleran glaciers in southern Alaska and the western conterminous United States deposited during the last glaciation. Itkillik I moraines represent the maximum ice advance under cold full-glacial conditions between about 24,000 and 17,000 14C y. a. Itkillik II sediments, probably deposited close to 14,000 y. a., are characterized by abundant outwash and ice-contact stratified drift implying a milder climate than that of the Itkillik I phase. Alapah Mountain moraines at the heads of valleys draining high-altitude (≥1800 m) source areas record a possible late Itkillik readvance that is not yet closely dated. Itkillik glaciers may have largely disappeared from Brooks Range valleys by the beginning of the Holocene.
Reconstructing the Rate of Accumulation of Lake Sediment: The Effect of Sediment Focusing
Authors: Lehman John T.
Published: December 2004

Use of accumulation rates of pollen or minerals to infer regional history is complicated by nonuniform deposition of lake sediment. Sediment focusing, direction of sediment to the deepest part of a basin, can introduce a discrepancy between changes in accumulation rates measured directly from sediment cores and actual changes in influx of sediment or pollen to a lake. This difference depends on values and temporal variation of the ratio of mean depth to maximum depth in a basin as it fills. Several models of sediment accumulation show how measurements from a single core can be transformed to yield basinwide influx rates, and how the distortion due to sediment focusing can be assessed. Basins shaped like hyperboloids or frustums may introduce much greater distortions than basins conforming to ellipsoid or sinusoid shapes.
Paleobotany of Wisconsinan Interstadials, Eastern Great Lakes Region, North America
Authors: Berti Albert A.
Published: December 2004

This study concerns the pollen and plant macrofossils from Mid-Wisconsinan Interstadial sites within the Wisconsinan ice margin in eastern North America. The time period covered is from about 55,000 years BP to 22,500 years BP, an interval much longer than the postglacial. Sediments examined are principally those of large lakes deposited in the Erie and Ontario basins during intervals of ice retreat.

The Port Talbot I Interval (from about 55,000 to 50,000 years BP) in the Erie basin is characterized by pollen assemblages alternating from Pinus-dominated zones to ones with abundant Pinus, Quercus, and nonarboreal pollen. These assemblages are interpreted as indicating relatively warm and dry conditions. Mean July temperatures fluctuated between 15 and 21°C.

During the succeeding Port Talbot II Interval and Plum Point Interstadial, in both the Erie and Ontario basins, pollen assemblages are characterized by dominant Pinus and Picea. Characteristic macrofossils include needles of the boreal Picea and Larix and leaves of species with a more northerly distribution, such as Dryas integrifolia, Betula glandulosa var. glandulosa, Vaccinium uliginosum var. alpinum, and Salix herbacea. These fossil assemblages are interpreted as indicating cooler and moister conditions in a forest-tundra environment. Mean July temperatures fluctuated between 10 and 15°C during the Port Talbot II Interval and Plum Point Interstadial.
Surface Albedo Increase following Massive Pleistocene Explosive Eruptions in Western North America
Authors: Bray J. R.
Published: December 2004

The eight massive Pleistocene explosive volcanic eruptions which occurred in western North America produced rhyolitic ash layers estimated to have covered from 0.38 to 2.76 × 106 km2 of the western and central portions of the continent. The surface albedo increases in the Northern Hemisphere resulting from these light-colored ash covers varied from around 0.06 to 0.41% assuming ash albedos based on color of around 53 to 65%. These albedo increases resulted in hemispheric temperature decreases of from around 0.07° to 0.41°C with greater cooling in and adjacent to the ash-covered regions. Such albedo-induced temperature declines lasted for at least several decades and reenforced the substantial posteruption cooling caused by volcanic aerosols and by a feedback decrease in atmospheric precipitable water. The magnitude and critical location of these temperature declines may have contributed to summer snow survival in the sub-Arctic plateaus and to a consequent triggering of major Pleistocene glaciations.
Predicted Relative Sea-Level Changes (18,000 Years B.P. to Present) Caused by Late-Glacial Retreat of the Antarctic Ice Sheet
Authors: Clark James A. , Lingle Craig S.
Published: December 2004

Predictions of global changes in relative sea level caused by retreat of the Antarctic Ice Sheet from its 18,000 yr B.P. maximum to its present size are calculated numerically. When combined with the global predictions of relative sea-level change resulting from retreat of the Northern Hemisphere ice sheets, the results may be compared directly to observations of sea-level change on the Antarctic continent as well as at distant localities. The comparison of predictions to the few observations of sea-level change on Antarctica supports the view that the Antarctic Ice Sheet was larger 18,000 years ago than at present. The contribution of the Antarctic Ice Sheet to the total eustatic sea-level rise is assumed to be 25 m (25% of the assumed total eustatic rise). If as little as 0.7 m of this 25-m rise occurred between 5000 yr B.P. and the present, few mid-oceanic islands would emerge. If the Antarctic Ice Sheet attained its present dimensions by 6000 yr B.P., however, and if the volume of the ocean has remained constant for the past 5000 years, numerous islands throughout the Southern Hemisphere would emerge. It is suggested that a thorough study of Pacific islands, believed by some to have slightly emerged shorelines of Holocene age, would yield useful information about ocean volume changes during the past 5000 years, and hence on the glacial history of the Antarctic Ice Sheet.
Vegetation and Climates in Southern Tasmania since the Last Glaciation
Authors: Macphail Michael K.
Published: December 2004

Enclosed basins (glacial and nonglacia) of Tasmania contain the most comprehensive record in Australia of trends in a regional vegetation and climate since the late Pleistocene. Seven pollen sequences, each continuous and extending back at least 10,000 years, are used to reconstruct the history of postglacial vegetation and climate in Southern Tasmania (42°S–43°30′S). Interpretations are supported by a study of the modern pollen rain. Postglacial climates in Tasmania were characterized by a strong west-to-east decrease in precipitation. During the late Pleistocene, climates were markedly colder and drier than at present, and the vegetation was largely devoid of trees. A major rise in temperature between ca. 11,500 and 9500 yr B.P., accompanied by rising effective precipitation, resulted in the expansion ofEucalyptus, then other trees, across Tasmania. This warming trend may have been temporarily reversed during the early postglacial. Dry climates delayed the development of forest in inland eastern Tasmania until after ca. 9500 yr B.P. There is no evidence for a major change in climate since this temperature rise. Two broad phases of development have occurred within the postglacial forests. The first was an early Holocene phase during whichNothofagus cunninghamiicool temperate rain forest developed in western Tasmania and on the slopes of mountains in central and southeastern Tasmania.Eucalyptussclerophyll forests developed in eastern Tasmania and have remained dominant there since. By ca. 7800 yr B.P. rain-forest communities were established beyond present-day limits. The second phase was a mid to late Holocene phase during which forests and alpine vegetation became more open in structure, leading to the re-expansion ofEucalyptusand shade-intolerant species. During the early to mid Holocene, climates in Southern Tasmania were wetter and (? then) warmer than at present. Maximum and minimum dates for this “optimum” are 8000 and 5000 yr B.P. Since then, climates have become increasingly rigorous, possibly through an increased incidence of inequable “weather types” leading to an increase in the frequency of drought and frost. Structural changes in the postglacial vegetation of Southern Tasmania closely parallel those at equivalent latitudes in New Zealand and Chilean South America, hence are likely to reflect the same primary cause.