bluuebunny/crossref_metadata_2025 huggingface dataset:
Holocene sea-level change and coastal evolution in the Humber estuary, eastern England: an assessment of rapid coastal change
Authors: Long A. J. , Innes J. B. , Kirby J. R. , Lloyd J. M. , Rutherford M. M. , Shennan I. , Tooley M. J.
Published: January 2003

New stratigraphic data collected from six sites in the Humber estuary establish a record of Holocene relative sea-level (RSL) change, and enable testing of four possible causes of rapid coastal change: sea-level rise, changes in sedimentation, storm-surge history, and human impact. Mean high water of spring tides (MHWST) in the Humber rose from c. 9 m OD at 7500 cal. yrs BP to 0 m OD by 4000 cal. yrs BP, at an average long-term rate of c. 3.9 mm yr-1. After this, the rate of rise gradually decreased to c. 1 mm yr’. Discrete episodes of rapid RSL rise are not identified although their absence may reflect limited data availability. However, we do observe two episodes of rapid coastal change in the Humber estuary. The first occurs between c. 3200 and 1900 cal. yrs BP, as marine conditions expand to their Holocene maximum and then contract. This pattern of coastal development differs from that in the East Anglian Fenlands, suggesting local processes control sedimentation at one or both of these sites. The second period of rapid change relates to a well-documented episode of increased storm surge activity in the Humber estuary and elsewhere in the UK and the North Sea region between c. 700 and 500 cal. yrs BP. Coastal development during this period varies considerably with erosion, accretion and flooding in different parts of the estuary system. Finally, we examine evidence for accelerated sediment delivery to the Humber estuary due to woodland clearance and prehistoric agriculture from 5700 cal. yrs BP onwards. Maximum sediment input is likely at c. 3200 to 1900 cal. yrs BP; a period which tentatively correlates with an episode of estuary infilling and shoreline advance.
Landscape openness and pollen records: a simulation approach
Authors: Sugita S. , Gaillard M.-J. , Broström A.
Published: January 2003

Quantitative reconstruction of the area cleared of forest in the past is essential to assess the possible indirect anthropogenic impacts on the past environment of Europe, including past climate. We apply a simul ation model of pollen dispersal and deposition (1) to re-examine the relationship between pollen and landscape openness, often uncritically inferred from non-arboreal pollen (NAP) percentages alone, and (2) to predict the relevant source area of pollen, the smallest spatial scale of vegetation that can be reconstructed from pollen records. The simulations use landscapes simplified from the modern open agricultural and semi-open forested regions in southern Sweden where traditional cultural landscapes still remain. The model is appropriate, because the simulated pollen assemblages resemble the pollen assemblages observed in each of the two landscape types, and because the simulated relationships between NAP percentages and percentage cover of open land within 1000 m agree with the empirical relationships. The simulated relevant source area of pollen is the area within 800–1000 m from both small hollows and 3-ha ponds. NAP percentages give only a rough first approximation of the percentage cover of open land. More comprehensive methods will be required to obtain quantitative estimates of open land from fossil pollen.
Calibration of the speleothem delta function: an absolute temperature record for the Holocene in northern Norway
Authors: Lauritzen Stein-Erik , Lundberg Joyce
Published: January 2003

The speleothem delta function (SDF) provides a new transfer function between the d18O signal of speleothem calcite and surface ground temperature. The function is based on physical principles, relating d18O of the calcite to thermodynamic fractionation, and to the dripwater function, which in turn relates d18O of dripwaters to that of the local precipitation and thus to the modification of source water in relationship to the geographical position of the site. The SDF must be calibrated against at least two reliable and well-dated palaeotemperature points. The end product is a reconstruction of absolute cave and surface temperatures. The technique is tested using a Holocene speleothem from north Norway, SG93, dated by 12 TIMS U-Th dates. The reconstructed temperature curve is presented and compared with the GISP2 ice-core record and with the historic record. In both cases the correlation with SG93 is impressive, indicating the validity of the technique.
Prehistoric farming and the postglacial expansion of beech and hombeam: a comment on Küster
Authors: Gardner A. R. , Willis K. J.
Published: January 2003

Küster (1997) has argued that human activity rather than climatic ‘deterioration’ has been responsible for the postglacial expansion of beech (Fagus sylvatica) and hornbeam (Carpinus hetulus) into the oak (Quercus sp.) woodlands of central Europe. We concur that climatic change plays a subordinate role to human activity in the establishment of these taxa, although we feel that the approach adopted by Küster overlooks important ecological and methodological issues. Furthermore, we argue that the expansion of beech is an entirely natural phenomenon which would have occurred without anthropogenic interference but which coincides with early agricultural activity as a result of slow migration and establishment rates. Here we present data from four new palaeoecological sequences collected from sites in Slovenia and Hungary that reveal fluctuations in established forest during the postglacial. In the Slovenian example, anthropogenic activity is seen to reduce beech forest while hornbeam and oak expand to fill the gaps. In the Hungarian examples the response is more complex and includes fluctuations in hazel (Corylus avellana) in addition to hornbeam and oak.
Timing and significance of talus slope reworking, Trotternish, Skye, northwest Scotland
Authors: Hinchliffe Simon
Published: January 2003

Exposures through the upper rectilinear (or near rectilinear) segment of vegetated, relict talus slopes at the foot of the Trotternish escarpment, northern Skye, exhibit stacked debris flow diamictons intercalated with surface wash horizons and occasional buried organic palaeosols, thus indicating a long history of reworking at this site. Radiocarbon dates for the tops of buried palaeosols indicate that reworking of sediment locally predates 5.9–5.6 cal. ka BP, and has been intermittently active throughout the late Holocene. Broad coincidences of timing are evident for the onset of reworking of different sectors of the talus slope at c. 5.9–5.6 cal. ka BP, c. 2.3–1.7 cal. ka BP and c. 0.7–0.5 cal. ka BP, that may represent more widespread reworking. Analysis of subfossil palynomorphs within some buried palaeosols suggests that most reworking postdates the main period of local, anthropogenic woodland clearance dated to the mid-Holocene. Buried palaeosols examined contain no evidence of local burning of vegetation. These findings appear to exclude anthropogenic interference with vegetation as a possible cause of late-Holocene erosion of this talus. Evidence for alternative causes of reworking is largely inferential. One hypothesis is that the timing of phases of reworking may reflect the occurrence of climatic events of sufficient magnitude to induce talus slope failure (extreme events). If so, an implication of this finding is that talus deposits may be highly sensitive to climate and could ultimately yield a proxy-record of extreme event occurrence.
High-altitude vegetational pattern on the Iberian Mountain Chain (north-central Spain) during the Holocene
Authors: Goñi María Fernanda Sánchez , Hannon Gina E.
Published: January 2003

Pollen, plant macrofossil. charcoal, sedimentary analyses and magnetic susceptibility measurements have been carried out on a C-14 dated sediment sequence from Las Pardillas Lake (1850 m a.s.l., Iberian Mountain Chain). The interpretation of the pollen diagram has been assisted by the analysis of an altitudinal transect of moss-polsters collected in the same area. After 9310 BP, a Pinus-Betula-Quercus open woodland developed. Between c. 9000 BP and 7100 BP, the woodland became a mixed forest with Pinus vylvestris. The beginning of the continuous curve of Corylus c. 9000 BP dated the local population expansion of this tree and is 1000 years earlier than the age previously attributed to its expansion in north-central Spain. At c. 7400 BP a local fire is associated with a possible first establishment of Fagu.s in the area. From c. 7100 BP to c. 3700 BP, Taxus, Rex and Hedera were present in the forest vegetation. During this interval, the pollen and sedmentological record indicated a stable period of rich, mixed Quercus forest. At the same time, the community of floating-leaved aquatics was replaced by submerged plants, suggesting that a rise in lake water level may have occurred between 7200 and 6400 BP. Fagus became continuously present in the Las Pardillas Lake area c. 3200 BP. As Fagus is fire-sensitive, the expansion and stand scale establishment may be linked to an increase in fire regime, a type of disturbance which has facilitated the spread of this taxon elsewhere in Europe. A significant forest reduction, involving all the trees, took place c. 1500 BP. Between 1000 and 400 BP, Pinus and Fugus re-expanded associated with the first clear evidence of agricultural activity. The well-represented, mixed Quercus forest around Las Pardillas Lake, and the early development of Coryluw compared to other Mediterranean zones, suggests that oceanic conditions prevailed on the northern slopes of these mountains in north-central Spain.
A diatom-based palaeosalinity history of Ace Lake, Vestfold Hills, Antarctica
Authors: Roberts Donna , McMinn Andrew
Published: January 2003

A comprehensive diatom stratigraphy is used to calculate a palaeosalinity history for an Antarctic lake via an established diatom-salinity transfer function for the Vestfold Hills, Antarctica. A sediment core taken from Ace Lake in 1995 shows three distinct changes in diatom assemblage constituents: initial benthic hyposaline – freshwater taxa are replaced by marine planktonic and sea-ice taxa with these taxa in turn replaced by the benthic hypersaline taxa dominant in the lake today. These changes in assemblage composition enable the lakewater salinity of each stage to be determined, and the Holocene evolution of the lake to be refined. Deglaciation of the Vestfold Hills at the beginning of the Holocene exposed Ace Lake basin; following this, fresh lacustrine diatoms were deposited from| 11 380 to| 8110 corrected 14C yr BP. Relative sea-level rise after this time led to the progressive marine inundation of the lake and the deposition of marine diatom taxa. Marine taxa were dominant in the sediment for more than 6000 years. Isostatic rebound and stabilization of the sea-level isolated Ace Lake and at| 1480 corrected 14C yr BP saline lacustrine diatoms became the domi nant taxa, indicative of the concentration of dissolved salts through evaporation after isolation.
A 3000-year high-resolution stalagmitebased record of palaeoclimate for northeastern South Africa
Authors: Holmgren K. , Karlén W. , Lauritzen S. E. , Lee-Thorp J. A. , Partridge T. C. , Piketh S. , Repinski P. , Stevenson C. , Svanered O. , Tyson P. D.
Published: January 2003

High-resolution stable isotope variations and growth structure analyses of the last three millennia of a 6600-year stalagmite record at Cold Air Cave, Makapansgat Valley, South Africa, are presented. Growth layers, which are measurable over the last 250 years, are shown to be annual. The correlation between the width of growth layers and precipitation is strongly positive. Changes inδ18O andδ13C are positively correlated and inversely correlated to changes in the colour of the growth layers in the stalagmite. Variations in colour are directly correlated with mean annual temperature. Dark colouration is the product of increased temperature and mobilization of organic matter from the soil, and is associated with wetter summers and enhanced growth of C4 grasses. Darker colouring and enrichedδ18O andδ13C reflect a warmer, wetter environment, whereas lighter colouring and depleted isotopic values are indicative of cooler, drier conditions. The dominant episode in the 3000-year record is the cool, dry 500-year manifestation of the‘Little Ice Age’, from ad 1300 to about 1800, with the lowest temperatures at around ad 1700. The four centuries from ad 900 to 1300, experiencing above-average warming and high variability, may be the regional expression of the medieval warming. Other cool, dry spells prevailed from around ad 800 to 900 and from about ad 440 to 520. The most prolonged warm, wet period occurred from ad 40 to 400. Some extreme events are shown to correspond well with similar events determined from the Greenland GISP2 ice-core record and elsewhere. Distinct periodicities occur within the record at around 120, 200–300, 500–600 and at about 800 years BP.
A 1119-year tree-ring-width chronology from western Prince William Sound, southern Alaska
Authors: Barclay David J. , Wiles Gregory C. , Calkin Parker E.
Published: January 2003

Living and subfossil trees from glacier forefields are used to develop a 1119-year-long tree-ringwidth chronology. Strong cross-dating among ring-width series from sites up to 60 km apart and an analysis of sample homogeneity support combination of all samples into a single, regional composite chronology. Comparison with instrumental climate data indicates May through July temperatures of the growth year are the primary control on ring-widths. Multidecadal-length warm periods in western Prince William Sound during the past 800 years were centred on AD 1300, 1440 and possibly 1820. Multidecadal-length cool periods were centred on AD 1400, 1660 and 1870. This is the first tree-ring chronology from the Gulf of Alaska region to extend into the first millennium AD.
Evidence for climatic deteriorations associated with the decline of Sphagnum imbricatum Hornsch. ex Russ. in six ombrotrophic mires from northern England and the Scottish Borders
Authors: Mauquoy Dmitri , Barber Keith
Published: January 2003

The decline of Sphagnum imbricatum from the peat stratigraphy of six ombrotrophic mires (Bolton Fell Moss and Walton Moss, Raeburn Flow and Bell's Flow, and Coom Rigg Moss and Felecia Moss), has been investigated using colorimetric humification, quantitative plant macrofossil, and testate amoebae analyses. The chronology of each peat profile was determined by radiocarbon assay and pollen/land-use correlations. Palaeoclimate reconstructions have been made by linking known documentary/historical changes in climate, and other proxy-climate records, to those inferred from the sites investigated in the study region. In two of the ombrotrophic mires examined, there are wet shifts associated with the decline and local extinction of S. imbricatum, which are dated to cal. ad 1160–1400 (Raeburn Flow and Bell's Flow). In Coom Rigg Moss and Felecia Moss, wet shifts are also associated with the decline and local extinction of S. imbricatum between cal. ad 1395–1485. The decline of S. imbricatum from two other ombrotrophic mires (Bolton Fell Moss Core L and Walton Moss Core 11) is dated to cal. ad 1030–1400, and may have been due to interspecific competition between Sphagnum species during the ‘Early Medieval Warm Period’ and the ‘Little Ice Age’.
Geological impacts on coastal wetland landscapes: some general effects of sediment autocompaction in the Holocene of northwest Europe
Authors: Allen J. R.L.
Published: January 2003

A simulation model is described providing general insights into autocompaction effects in stratigraphic sequences formed on coastal mudflats and marshes over uneven basements. Lithological units and buried landscapes are progressively displaced and distorted, the synthetic sequences resembling bedding geometries described from the northwest European Holocene. Autocompaction also promotes local deposition rates that may greatly exceed the rates at which accommodation space is created. Transgressive silts are associated with especially large deposition rates, because of the high compressibility of underlying peats. The experimental relationships between apparent rates of sea-level rise and bed thickness resemble empirical trends for the Holocene. The latter are, however, reinforced by an ‘intrinsic’, lithology-related effect not included in the model.
A kernel-based Bayesian approach to climatic reconstruction
Authors: Robertson I. , Lucy D. , Baxter L. , Pollard A. M. , Aykroyd R. G. , Barker A. C. , Carter A. H.C. , Switsur V. R. , Waterhouse J. S.
Published: January 2003

To understand recent climatic trends and possible future climatic change, it is necessary to examine the nature of past climatic variability. Proxy measures of past climatic fluctuations can be used to extend this record beyond the limited period of instrumental measurements. Regression-based techniques are generally used to define transfer functions, which describe the statistical relationship between these proxy estimates of past climate and measured climatic parameters. Although these regression-based techniques have been extremely successful, they can engender bias in the estimates if not used with care. More significantly, we show that if regression errors are explicitly calculated they are often similar in magnitude to the total range of the parameter being estimated, implying that such reconstructions of past climate cannot be regarded as truly precise. A novel approach based upon Bayes' theorem is introduced which appears to increase the statisti cal veracity of such climatic reconstructions.
Environmental changes of the last three centuries indicated by siliceous microfossil records from the southwestern Baltic Sea
Authors: Andrén Elinor , Shimmield Graham , Brand Timothy
Published: January 2003

Four short sediment cores from the southwestern Baltic Sea were analysed with respect to their content of siliceous microfossils. The aim was to detect and date changes in the composition of the diatom flora and to link these changes to variations in the anthropogenic load of nutrients during the last century. The study shows that the most significant change in the diatom assemblages occurred 130-140 years ago. The change is recorded in the sediments as a shift from periphytic diatom taxa to a predominance of planktonic taxa. This indicates that the photic layer has decreased in depth, probably due to eutrophication of the Baltic Sea, which consequently began to affect the area investigated approximately AD 1850. To support the results of a changing ratio of periphytic to planktonic diatoms, diatom accumulation rates were calculated. In general, the diatom accumulation rate data show a decrease in the periphytic accumulation rates and an increase in the planktonic accumulation rates towards the sediment surface. Some indications of a colder climate are recorded in the sediments approximately 230 years ago. These results are in accordance with the record of maximum extent of sea ice in the same area and are suggested to represent a late stage in the ‘Little Ice Age’.
An expanded calibration model for inferring lakewater and air temperatures from fossil chironomid assemblages in northern Fennoscandia
Authors: Olander H. , Birks H. J. B. , Korhola A. , Blom T.
Published: January 2003

Chironomid-temperature inference models based on an expanded data set of surface-sediment and limnological data from 53 Subarctic lakes in northern Fennoscandia have been developed using eight different numerical techniques, each based on slightly different underlying statistical models or ecological assumptions. The study sites are mostly small, shallow, bathymetrically simple, oligotrophic lakes, with a pH range from 5.0 to 7.8, a total organic carbon range from 2.5 to 12.6 mg l-1, a mean July lakewater temperature ranging from 6.1 to 15.4°C, and a mean July air temperature ranging from 8.5 to 14.9°C. A series of redundancy analyses (RDA) identified sediment organic content, maximum lake depth, and lakewater temperature as being the most important explanatory variables. Variance partitioning by partial RDAs further suggested that each of these variables accounted for a significant fraction of variance independent from each other. Different cali bration models were assessed on the basis of their statistical performance, with particular reference to prediction errors and the amount of bias along the temperature gradient. Of the eight calibration models, modern analogue techniques, weighted averaging partial least squares, simple weighted averaging with an‘inverse’ deshrinking regression, and linear partial least squares consistently performed best. These methods can all be used to develop transfer functions for surface-water and air July temperatures with a root mean squared error of predic tion (RMSEP) of about 1.5–1.6°C (water temperature) and 0.8–1.1°C (air temperature), as assessed by leave-one-out cross-validation. The resulting models do, however, have relatively high maximum biases (up to 3.9°C) in the lowest segments of the air and water temperature gradients, highlighting the need for enlarging and expanding the calibration data set to include lower temperatures.
Effect of meso-2,3-dimercaptosuccinic acid on urinary lead excretion in exposed men
Authors: Torres-Alanís O , Garza-Ocañas L , Piñeyro-López A
Published: January 2003

The efficacy of meso-2,3-dimercaptosuccinic acid (DMSA) was evaluated in workers occupationally exposed to lead (Pb; blood level >50 mg //dL). Ten men were given 600 mg of DMSA per orem daily, for five days. Pb concentrations of whole blood and urine were determined throughout therapy. Hematology analyses, blood chemistry, and urinalysis were obtained at the start of the study, at the end of the DMSA treatment, and at 72 hours after the administration of the final dose. DMSA therapy had no influence on hepatic, hematologic, or renal functions and was effective in decreasing the concentration of blood Pb in all the subjects without adverse drug reactions.
Steroidogenic alterations in testes and sera of rats exposed to formulated Fenvalerate by inhalation
Authors: Mani U , Islam F , Prasad A K , Kumar P , Kumar V Suresh , Maji B K , Dutta K K
Published: January 2003

Fenvalerate (Fen) is a synthetic pyrethroid, which is commonly used for destroying a variety of insect pests damaging several vegetable, fruit, and cotton crops. This insecticide is also used to mitigate household insects like flies, cockroaches, mosquitoes, and so forth. Human beings are exposed to formulated Fen preparations mostly by inhalation during spraying in fields for crop protection, for control of household insects, and also during handling and packaging at manufacturing plants. Limited online information is available regarding toxic effects of formulated Fen exposure on mammalian reproductive system. The present study has been undertaken to investigate male reproductive toxic effects of a formulated preparation of Fen (20% EC) particularly in relation to steroidogenic alterations in testes and sera of rats exposed by nose-only inhalation for (4 hours/day and five days a week) for three months. The results indicate significant reduction in the weight of testes, epididymal sperm counts, and sperm motility, along with decrease in marker testicular enzymes for testosterone biosynthesis viz. 17-b-hydroxy steroid dehydrogenase (17-b-HSD) and glucose-6-phosphate dehydrogenase (G6PDH), leading to net decrease in serum testosterone concentration in group of rats exposed to onefifth LC50 of Fen (20% EC) by inhalation (4 hours/day, five days a week) subchronically for three months. These results for the first time indicate the role of testosterone in Fen (20% EC)-induced male reproductive toxicity of rats subchronically exposed by inhalation probably due to neuroendocrine-mediated phenomenon and hormone-disrupting property of the insecticide.
Traditional medicine poisoning in Zimbabwe: clinical presentation and management in adults
Authors: Tagwireyi D , Ball D E , Nhachi C F B
Published: January 2003

Traditional medicines (TMs) have been reported as major causes of hospital admissions in some African countries including Zimbabwe. There is, however, still a paucity of information with regards to their clinical presentations. We carried out a retrospective case series of all cases of traditional medicine poisoning (TMP) at eight main referral hospitals in Zimbabwe (January 1998–December 1999 inclusive) to describe the most common signs and symptoms, reasons for, and management of TMP in adults. Where the reasons for taking the TM were known, most cases had taken the medicine for either abdominal pains or aphrodisiac purposes. Nonspecific adverse effects including vomiting, abdominal pains, and diarrhoea were the most commonly encountered. A large proportion of patients with TMP also suffered from genito-urinary tract adverse outcomes especially haematuria and dysuria. Intravenous fluids were the most commonly employed therapeutic modality for TMP, probably in an effort to dilute or increase excretion of the toxins. Further research is required to elucidate the toxic components responsible for the observed ill effects and whether these effects are due to the medicines themselves or to co-existing illnesses.
Fatal overdosage with sildenafil citrate (Viagra1): first report and review of the literature
Authors: Tracqui A , Miras A , Tabib A , Raul J S , Ludes B , Malicier D
Published: January 2003

A fatal case of sildenafil citrate (Viagra1) overdosage is presented. The deceased was a 56-year old male found dead at home, with a past history of diabetes mellitus, hypertension, chronic alcoholism, anxio-depressive disorders, and erectile dysfunction. The main autopsy findings were cardiomegaly (650 g) with dilated cardiomyopathy, diffuse coronary atherosclerosis with no sign of acute ischaemic disease, and extensive fibrosis of the myocardium, especially affecting the cardiac conducting tissue. As measured by HPLC/MS, sildenafil concentration in postmortem blood (6.27 mg/mL) exceeded at least four times the highest therapeutic levels previously reported. The results are discussed in the light of the literature about the cardiovascular side effects of sildenafil, with special emphasis on the recently evidenced arrhythmogenic potential of the drug. This is the first report of a fatality caused by sildenafil overdosage.
Flunitrazepam variably alters morphine, buprenorphine, and methadone lethality in the rat
Authors: Borron S W , Monier C , Risède P , Baud F J
Published: January 2003

Opiates and substitution products are frequently abused, alone and in association with benzodiazepines. While this combination may result in severe respiratory depression and death, the quantitative relationship remains uncertain. We performed randomized, blinded intravenous median lethal dose (MLD) studies in Sprague–Dawley rats of morphine, buprenorphine, and methadone, alone and in combination with intraperitoneal flunitrazepam pretreatment. We employed the up-and-down method, performed in quadruplicate, comparing time to death following opioid injection. Results are expressed as median of four series (extremes). The MLDs of morphine, buprenorphine, and methadone alone were 64.0 (33.6:79.5), 234.6 (168.6:284.4), and 22.5 (19.3:24.1) mg/kg, respectively, and 60.6 (35.2:88.2), 38.4 (30.6:54.0), and 13.0 (9.7:13.8) mg/kg, respectively, after pretreatment with 40 mg/kg flunitrazepam. Times to death for morphine, buprenorphine, and methadone alone were 2.5 (0.8:24), 0.02 (0.0:24), and 2.0 (0.0:24) hours, respectively, and 13.5 (0.0:144), 24.0 (0.0:120), and 0.0 (0.0:24) hours, respectively, after pretreatment with flunitrazepam 40 mg/kg, ip. Flunitrazepam significantly altered methadone (P=0.02) and buprenorphine (P=0.02) but not morphine lethality (P=0.77). Flunitrazepam significantly prolonged time to death only for buprenorphine (P<0.01). Flunitrazepam–opioid drug–drug interactions are more complex than is generally believed. Mechanistic studies of flunitrazepam–opioid lethal interactions are needed.
Intermittent pneumatic compression for the treatment of lower extremity arterial disease: a systematic review
Authors: Labropoulos Nicos , Wierks Carl , Suffoletto Brian
Published: January 2003

This study aimed to identify the role of intermittent pneumatic compression in treating peripheral arterial disease and to investigate the types of treatment programs that are most effective. Data was sourced from English-language articles which were identified by a computer search using MEDLINE from 1966 to 2001, followed by extensive bibliography review. Studies were included if they contained pertinent material involving a compression device and arterial flow dynamics in lower limbs. A total of 26 English-language studies were identified that met the inclusion criteria. The diverse patient criteria and methods used in the studies provided an opportunity to examine the effectiveness of each, but made it difficult to compare one study with another. To assist in focusing on overall trends in improvement, patient type and treatment type disparities must be identified. In conclusion, it is evident that an intermittent pneumatic compression program appears promising and may be used in patients with severe peripheral arterial disease who are not candidates for revascularization using surgery or percutaneous angioplasty. It is now the goal to establish randomized, prospective, controlled trials to clarify the most beneficial regimen for treating such disease.
Effect of cardiac cycle on ultrasound assessment of endothelial function
Authors: Chuang Michael L , Douglas Pamela S , Bisinov Elizabeth A , Stein James H
Published: January 2003

To investigate the effects of non-ECG-triggered imaging during ultrasound studies of endothelial function, brachial artery diameters were measured throughout the cardiac cycle at rest, during reactive hyperemia, and after administration of nitroglycerin. R-wave-triggered imaging using a 7.5-MHz ultrasound transducer with acquisition every 41.7-66.7 ms was performed in 24 subjects. Cardiac cycle-related variation was computed as the maximum per cent change from the end-diastolic diameter. The range of possible errors in flow-mediated dilation (FMD) and nitroglycerin-mediated vasodilation that may result from ignoring cyclic variations in diameter was determined for each condition.

True FMD, true nitroglycerin-mediated vasodilation, and the maximum and minimum values that could be erroneously calculated for FMD if timing was ignored all differed dramatically (p 0.05). The range of apparent FMD values that could be measured was nearly three times the true FMD value. Ignoring temporal position within the cardiac cycle artifactually increased calculated FMD into the normal range, despite truly impaired FMD. Peak arterial dilation occurred before end-systole and greater baseline vessel compliance was associated with greater FMD.

Brachial arterial diameters vary significantly throughout the cardiac cycle. The magnitude of this variation is similar to the arterial dilation induced by reactive hyperemia and nitroglycerin, making ECG-triggered imaging mandatory for accurate and reproducible clinical and research measurements of artery diameters and FMD. Measurement of diameters at end-diastole may be preferred to other time-points in the cardiac cycle.
Laboratory thrombophilias and venous thromboembolism
Authors: Joffe Hylton V , Goldhaber Samuel Z
Published: January 2003

Inherited abnormalities of coagulation are increasingly recognized in patients with venous thromboembolism. Common causes of hypercoagulability, also known as thrombophilia, include factor V Leiden, the prothrombin gene mutation, hyperhomocysteinemia, and antiphospholipid antibodies. Thrombophilia should be suspected in patients who develop idiopathic venous thromboembolism at a young age, recurrent thrombosis, thromboses at unusual sites, recurrent unexplained pregnancy loss, or if there is a family history of thrombotic disorders. The most cost-effective approach is to initially screen for factor V Leiden, the prothrombin gene mutation, hyperhomocysteinemia, and antiphospholipid antibodies because these are the most common defects causing thrombophilia. Long-term anticoagulation is controversial but should be considered if unprovoked venous thromboembolism recurs.
Activities as a vehicle for linguistic and sociocultural knowledge at the elementary level
Authors: Huang Jingzi
Published: January 2003

This paper reports on a content-based elementary Chinese as a foreign language programme. It focuses on classroom language activities that are designed and implemented to serve the dual goals of language development and cultural learning. From a sociocultural perspective, it investigated how classroom activities are organized to integrate culture/content and language learning for young beginners. Two themes are highlighted in the discussion: (1) initial teacher planning vs. curriculum as experienced; (2) graphic organizers and language product. The result of the study throws light on the possibilities of a wide range of systematic form-function relations in the classroom, the integration of language and content learning, and on further directions for intentional planning in any other second or foreign language teaching programmes. It also reveals potential for implementing content-based foreign language instruction at the elementary level even in a situation where the teacher is still working on her own language proficiency.
Enhanced anaerobic degradation of polymeric azo compounds by Escherichia coli in the presence of low-molecular-weight redox mediators
Authors: Rau J , Maris B , Kinget R , Samyn C , van den Mooter G , Stolz A
Published: January 2003

The effects of the redox mediator lawsone (2-hydroxy-1,4-naphthoquinone) on the ability of Escherichia coli to reduce anaerobically polymeric azo compounds were analysed. Two types of polymeric azo compounds were tested, that have been proposed as putative tools for the site-specific targeting of drugs to the colon. The first group of polymers consisted basically of linear chains of polymethacrylic acid or polymethylmethacrylate which were interrupted by subunits of 4,4′-bis-(methacryloylamino)azobenzene. These polymers differed significantly in their hydrophilicity according to the relative proportion of polymethacrylic acid used for the polymerization procedure. The second group of polymers consisted of almost water-insoluble poly(ether-ester)azo polymers that were composed of 4-(6-hydroxyhexyl)oxy-phenylazobenzoate and 16-hydroxyhexadecanoate. The addition of lawsone to the anaerobically incubated cultures of E. coli resulted in a pronounced increase in the reduction rates of the water-soluble poly(methacrylate-co-4,4′-bis(methacryloyl-amino)azobenzene) and in a much smaller, but significant, increase in the reduction rates of the hydrophobic poly(ether-ester)azo polymers. An increase in the amount of azo groups resulted, for the hydrophobic poly(ether-ester)azo polymers, in an increased reduction rate in the presence of the redox mediator lawsone.
Assessment of estrogenic activity in some common essential oil constituents
Authors: Howes M-J R , Houghton P J , Barlow D J , Pocock V J , Milligan S R
Published: January 2003

Estrogenic responses have not only been associated with endocrine function, but also with cognitive function. Several studies have indicated that estrogen replacement therapy has favourable effects on cognition, and may have potential in the prevention and treatment of Alzheimer's disease. Thus, ligands for the estrogen receptor, that have a better efficacy and adverse-effect profile than drugs currently available, require investigation. This study was undertaken to investigate the potential estrogenic activity of a number of essential oil constituents. Initially, estrogenic activity was determined by a sensitive and specific bioassay using recombinant yeast cells expressing the human estrogen receptor. At high concentrations, estrogenic activity was detected for citral (geranial and neral), geraniol, nerol and trans-anethole, while eugenol showed anti-estrogenic activity. Molecular graphics studies were undertaken to identify the possible mechanisms for the interaction of geranial, neral, geraniol, nerol and eugenol with the ligand-binding domain of the estrogen α-receptor, using the computer program HyperChem. Citral, geraniol, nerol and eugenol were also able to displace [3H]17β-estradiol from isolated α- and β-human estrogen receptors, but none of these compounds showed estrogenic or anti-estrogenic activity in the estrogen-responsive human cell line Ishikawa Var I at levels below their cytotoxic concentrations, and none showed activity in a yeast screen for androgenic and anti-androgenic activity. The potential in-vivo estrogenic effects of citral and geraniol were examined in ovariectomized mice, but neither compound showed any ability to stimulate the characteristic estrogenic responses of uterine hypertrophy or acute increase in uterine vascular permeability. These results show that very high concentrations of some commonly used essential oil constituents appear to have the potential to interact with estrogen receptors, although the biological significance of this is uncertain.
Rapid effect of progesterone on the contraction of rat aorta in-vitro
Authors: Zhang Meili , Wang G J , Benishin Christina G , Pang Peter K T
Published: January 2003

Progesterone induced rapid relaxation of KCl-induced contraction of rat aortic rings. The relaxant effect of progesterone on aortic rings was concentration-dependent (over the range of 10−10 to 10−5M) and partially dependent on the endothelium. Application of a nitric oxide (NO) synthase antagonist NG-monomethyl-L-arginine (L-NMMA, 10−5M) after progesterone treatment partially inhibited the relaxant effects of progesterone. This suggested that part of the effect was through the production of nitric oxide. Washing out the steroid hormone in the bath solutions could quickly reverse the inhibitory effects of progesterone on phasic tension generation in aortic rings. Five minutes after washout, the tension generation in aortic rings was completely restored. Cultured endothelial cells from rat aorta increased release of NO into culture media in response to a 60-min exposure to progesterone. Aldosterone and dexamethasone were also tested, and failed to relax KCl- induced contraction of aortic rings. These data suggest that the vascular effects of progesterone are not mediated by a genomic action of this steroid, and that the vascular effects are mediated partially through endothelial NO production.
Redox signaling in the growth and development of colonial hydroids
Authors: Blackstone Neil W.
Published: January 2003

Redox signaling provides a quick and efficient mechanism for clonal or colonial organisms to adapt their growth and development to aspects of the environment, e.g. the food supply. A `signature' of mitochondrial redox signaling, particularly as mediated by reactive oxygen species (ROS), can be elucidated by experimental manipulation of the electron transport chain. The major sites of ROS formation are found at NADH dehydrogenase of complex I and at the interface between coenzyme Q and complex III. Inhibitors of complex III should thus upregulate ROS from both sites; inhibitors of complex I should upregulate ROS from the first but not the second site, while uncouplers of oxidative phosphorylation should downregulate ROS from both sites. To investigate the possibility of such redox signaling, perturbations of colony growth and development were carried out using the hydroid Podocoryna carnea. Oxygen uptake of colonies was measured to determine comparable physiological doses of antimycin A1 (an inhibitor of complex III),rotenone (an inhibitor of complex I) and carbonyl cyanide m-chlorophenylhydrazone (CCCP; an uncoupler of oxidative phosphorylation). Using these doses, clear effects on colony growth and development were obtained. Treatment with antimycin A1 results in `runner-like'colony growth, with widely spaced polyps and stolon branches, while treatment with CCCP results in `sheet-like' growth, with closely spaced polyps and stolon branches. Parallel results have been obtained previously with azide, an inhibitor of complex IV, and dinitrophenol, another uncoupler of oxidative phosphorylation. Perhaps surprisingly, rotenone produced effects on colony development similar to those of CCCP. Assays of peroxides using 2′,7′-dichlorofluorescin diacetate and fluorescent microscopy suggest a moderate difference in ROS formation between the antimycin and rotenone treatments. The second site of ROS formation (the interface between coenzyme Q and complex III) may thus predominate in the signaling that regulates colony development. The fat-rich, brine shrimp diet of these hydroids may be relevant in this context. Acyl CoA dehydrogenase, which catalyzes the first step in the mitochondrial β-oxidation of fatty acids,carries electrons to coenzyme Q, thus bypassing complex I. These results support a role for redox signaling, mediated by ROS, in colony development. Nevertheless, other redox sensors between complexes I and III may yet be found.
The snakeheadChanna asiaticaaccumulates alanine during aerial exposure, but is incapable of sustaining locomotory activities on land through partial amino acid catabolism
Authors: Chew Shit F. , Wong Mei Y. , Tam Wai L. , Ip Yuen K.
Published: January 2003

The freshwater snakehead Channa asiatica is an obligatory air-breather that resides in slow-flowing streams and in crevices near riverbanks in Southern China. In its natural habitat, it may encounter bouts of aerial exposure during the dry seasons. In the laboratory, the ammonia excretion rate of C. asiatica exposed to terrestrial conditions in a 12h:12h dark:light regime was one quarter that of the submerged control. Consequently, the ammonia contents in the muscle, liver and plasma increased significantly, and C. asiatica was able to tolerate quite high levels of ammonia in its tissues. Urea was not the major product of ammonia detoxification in C. asiatica, which apparently did not possess a functioning ornithine urea cycle. Rather, alanine increased fourfold to 12.6μmolg-1 in the muscle after 48h of aerial exposure. This is the highest level known in adult teleosts exposed to air or an ammonia-loading situation. The accumulated alanine could account for 70% of the deficit in ammonia excretion during this period, indicating that partial amino acid catabolism had occurred. This would allow the utilization of certain amino acids as energy sources and, at the same time, maintain the new steady state levels of ammonia in various tissues, preventing them from rising further. There was a reduction in the aminating activity of glutamate dehydrogenase from the muscle and liver of specimens exposed to terrestrial conditions. Such a phenomenon has not been reported before and could, presumably, facilitate the entry of α-ketoglutarate into the Krebs cycle instead of its amination to glutamate, as has been suggested elsewhere. However, in contrast to mudskippers, C. asiatica was apparently unable to reduce the rates of proteolysis and amino acid catabolism, because the reduction in nitrogenous excretion during 48 h of aerial exposure was completely balanced by nitrogenous accumulation in the body. Alanine accumulation also occurred in specimens exposed to terrestrial conditions in total darkness, with no change in the total free amino acid content in the muscle. Exercise on land led to a decrease in glycogen content, and an increase in lactate levels, with no significant effect on ammonia and alanine contents in the muscle of C. asiatica. Hence, unlike the mudskipper Periophthalmodon schlosseri,C. asiatica was incapable of increasing the rate of partial amino acid catabolism to sustain locomotory activities on land. Alanine formation therefore appears to be a common strategy adopted by obligatory air-breathing fishes to avoid ammonia toxicity (not a strategy to detoxify ammonia) on land,but not all of them can utilize it to fuel muscular activities.
Biological impacts of deep-sea carbon dioxide injection inferred from indices of physiological performance
Authors: Seibel Brad A. , Walsh Patrick J.
Published: January 2003

A recent proposal to store anthropogenic carbon dioxide in the deep ocean is assessed here with regard to the impacts on deep-living fauna. The stability of the deep-sea has allowed the evolution of species ill-equipped to withstand rapid environmental changes. Low metabolic rates of most deep-sea species are correlated with low capacities for pH buffering and low concentrations of ion-transport proteins. Changes in seawater carbon dioxide partial pressure (PCO2) may thus lead to large cellular PCO2 and pH changes. Oxygen transport proteins of deep-sea animals are also highly sensitive to changes in pH. Acidosis leads to metabolic suppression, reduced protein synthesis,respiratory stress, reduced metabolic scope and, ultimately, death. Deep-sea CO2 injection as a means of controlling atmospheric CO2levels should be assessed with careful consideration of potential biological impacts. In order to properly evaluate the risks within a relevant timeframe,a much more aggressive approach to research is warranted.
Maneuverability by the sea lionZalophus californianus: turning performance of an unstable body design
Authors: Fish Frank E. , Hurley Jenifer , Costa Daniel P.
Published: January 2003

Maneuverability is critical to the performance of fast-swimming marine mammals that use rapid turns to catch prey. Overhead video recordings were analyzed for two sea lions (Zalophus californianus) turning in the horizontal plane. Unpowered turns were executed by body flexion in conjunction with use of the pectoral and pelvic flippers, which were used as control surfaces. A 90° bank angle was used in the turns to vertically orient the control surfaces. Turning radius was dependent on body mass and swimming velocity. Relative minimum radii were 9-17% of body length and were equivalent for pinnipeds and cetaceans. However, Zalophus had smaller turning radii at higher speeds than cetaceans. Rate of turn was inversely related to turn radius. The highest turn rate observed in Zalophus was 690 degrees s-1. Centripetal acceleration measured up to 5.1 g for Zalophus. Comparison with other marine mammals indicates that Zalophus has a morphology that enhances instability,thus providing enhanced turning performance. Enhanced turning performance is necessary for sea lions to forage after highly elusive prey in structurally complex environments.
Central effects of various ligands on drinking behavior in eels acclimated to seawater
Authors: Kozaka Tomohiro , Fujii Yasuaki , Ando Masaaki
Published: January 2003

Intracranial injection of eel angiotensin II (eANG II,5×10-13-5×10-8 mol), acetylcholine (ACh,5×10-12-5×10-9 mol), substance P(5×10-10 mol) and isoproterenol (a β-adrenoceptor agonist, 5×10-11-5×10-9 mol) enhanced water intake in the seawater eel. The effects of eANG II, ACh and isoproterenol were dose-dependent. By contrast, water intake was inhibited by intracranial injection of eel atrial natriuretic peptide (eANP,5×10-13-5×10-10 mol), serotonin (5-HT,5×10-12-5×10-8 mol), ghrelin(5×10-12-5×10-10 mol), γ-amino butyric acid (GABA, 5×10-11-5×10-8 mol), prolactin(PRL, 5×10-10-5×10-9 mol), arginine vasotocin (AVT, 5×10-12 mol), vasoactive intestinal peptide(VIP, 5×10-11 mol), noradrenaline (5×10-9mol l-1) and phenylephrine (α-adrenoceptor agonist,5×10-11-5×10-9 mol). The inhibitory effects of eANP, 5-HT, ghrelin, GABA, PRL and phenylephrine were dose-dependent. The intracranial stimulatory effect of eANG II was relatively long-lasting compared with the intravenous effect. The stimulatory effect of intravenous eANG II disappeared immediately, and was followed by an inhibition, which could be well explained by an increase in eANP secretion from the atrium.