bluuebunny/crossref_metadata_2025 huggingface dataset:
Case note. Kennewick man and native American graves protection and repatriation act woes
Authors: Zimmerman LJ , Clinton RN
Published: March 2007

The contentious, sometimes even raucous debate over the repatriation and reburial of Native American human remains has been calm compared to the clamor raised over the so-called Kennewick Man. Although the reburial debate has captured substantial worldwide media and public attention, the debate over the Kennewick find has done what no other case has so far managed - to raise a serious legal challenge to parts of the 1990 Native American Graves Protection and Repatriation Act (NAGPRA), a law providing for the return of human remains and burial artifacts to tribes. This case study examines the core issues surrounding the archaeological discovery, the entanglements related to NAGPRA, and possible impact of Kennewick on NAGPRA itself.
Case note. The native American graves protection and repatriation act: a benefit and a burden, refining NAGPRA's cultural patrimony definition
Authors: Goldman DE
Published: March 2007

This note discusses the United States v. Corrow decision. It focuses on the interpretation of cultural patrimony as defined by NAGPRA and emphasizes the dangers presented by this vague definition. The court in United States v. Corrow was the first to address whether the statute is unconstitutional because it is vague. This case is the first and only authority on NAGPRA's definition of cultural patrimony; therefore, the case and this note present significant avenues to understanding and thinking about cultural patrimony.
Vulture restaurants and their role in reducing diclofenac exposure in Asian vultures
Authors: GILBERT MARTIN , WATSON RICHARD T. , AHMED SHAKEEL , ASIM MUHAMMAD , JOHNSON JEFF A.
Published: March 2007

The provision of supplementary food at vulture restaurants is a well-established tool in the conservation of vulture species. Among their many applications, vulture restaurants are used to provide a safe food source in areas where carcasses are commonly baited with poisons. Rapid and extensive declines of vultures in the Indian subcontinent have been attributed to the toxic effects of diclofenac, a pharmaceutical used in the treatment of livestock, to which vultures are exposed while feeding on the carcasses of treated animals. A vulture restaurant was established at the Oriental White-backed Vulture Gyps bengalensis colony at Toawala, in Punjab province Pakistan, to test the effectiveness of the technique in modifying ranging behaviour and mortality at the colony. Six male vultures were fitted with satellite transmitters to describe variation in movement and home-range during periods when safe food was alternately available and withheld at the vulture restaurant. There was considerable variation in individual home-range size (minimum convex polygons, MCP, of 1,824 km2 to 68,930 km2), with birds occupying smaller home-ranges centred closer to the restaurant being more successful in locating the reliable source of food. Fixes showed that 3 of the tagged vultures fed at the vulture restaurant and the home-range of each bird declined following their initial visit, with a 23–59% reduction in MCP. Mean daily mortality during provisioning was 0.072 birds per day (8 birds in 111 days), compared with 0.387 birds per day (41 birds in 106 days) during non-provisioning control periods. Vultures tended to occupy greater home-ranges, cover greater distances each day and spend proportionately more time in the air during the late brooding and post-breeding seasons. Attendance at the vulture restaurant also declined during this period with fewer birds visiting less often and no tagged vultures visiting the vulture restaurant at all. These findings indicate that vulture restaurants can reduce, but not eliminate, vulture mortality through diclofenac exposure and represent a valuable interim measure in slowing vulture population decline locally until diclofenac can be withdrawn from veterinary use.
Vitamin and Mineral Inadequacy in the French Population: Estimation and Application for the Optimization of Food Fortification
Authors: Touvier  , Lioret  , Vanrullen  , Boclé  , Boutron-Ruault  , Berta  , Volatier
Published: March 2007

The objective was to assess the prevalence of inadequate micronutrient intake in a representative sample of the French population, which to our knowledge, had never been done before, and to use this concept to optimize efficiency and safety of food fortification. The INCA survey collected food intake data using a 7-day record, for 2373 subjects (4–92 years). The prevalence of inadequacy for calcium, magnesium, iron, vitamins C, A, B6, and B12, thiamin, riboflavin, niacin, pantothenic acid, and folate was estimated by the proportion of subjects with intake below the Estimated Average Requirement (EAR). We also calculated daily consumption of 44 food groups by age and gender. This paper shows how the combination of both data sets, i.e., inadequacy and food consumption data, allows a preliminary screening of potential food vehicles in order to optimize fortification. The prevalence of inadequacy was particularly high for the following groups: for calcium, females aged 10–19 years (73.5%) or aged 55–90 years (67.8%), and males aged 15–19 years (62.4%) or aged 65–92 years (65.4%); for magnesium, males aged 15–92 years (71.7%) and females aged 10–90 years (82.5%); for iron, females aged 15–54 years (71.1%); and for vitamin C, females aged 15–54 years (66.2%). Two examples are provided to illustrate the proposed method for the optimization of fortification.
Influence of Different Dietary Levels of Zinc on Performance, Vitamin B12, and Blood Parameters in Lambs
Authors: Wang  , Zhu  , Guo  , Zhang  , Jia
Published: March 2007

This experiment was conducted to investigate the influence of different dietary levels of zinc (Zn) on performance, vitamin B12, and blood parameters in lambs. Thirty six cannulated Poll Dorset × Small-tailed Han wether lambs were assigned randomly to four treatment groups: The control group, which was supplemented with 0.30 mg Co/kg dry matter (DM) to the basal diet; and the low-, medium- and high-Zn supplemented groups, supplementation of 50, 100, and 150 mg Zn/kg DM to the control diet, respectively. Lambs were housed in individual pens and the experiment lasted for 70 days. There was no significant difference in body weight gain and feed/gain between different treatment groups. The high-Zn supplemented lambs showed lower vitamin B12 concentrations in both ruminal fluid and plasma, and higher methylmalonic acid and homocysteine concentrations in plasma compared with the control and low-Zn supplemented groups (p < 0.05). No significant difference was observed in these biochemical values between the control, the low-, and the medium-Zn supplemented groups (p > 0.05). Plasma folate concentration, glucose, and heme-dependent blood parameters were not influenced by dietary zinc level. It was concluded that the higher level of zinc supplementation had a negative effect on vitamin B12 in lambs. Higher inclusion level of dietary zinc could inhibit vitamin B12 synthesis in the rumen of lambs.
The Relationship Between Antioxidant Nutrient Intake and Cataracts in Older People
Authors: Rodríguez-Rodríguez  , Ortega  , López-Sobaler  , Aparicio  , Bermejo  , Marín-Arias
Published: March 2007

This study investigated the relationship between the intake of antioxidant nutrients and the suffering of cataracts in 177 institutionalized elderly people (61 men and 116 women) aged ≥ 65 years. Dietary intake was monitored for 7 consecutive days using a "precise individual weighing" method. Subjects, who during their earlier years were exposed by their work to sunlight, had a greater risk of suffering cataracts (OR = 3.2; Cl: 1.1–9.3, P < 0.05) than those who worked indoors. A relationship was found between increased vitamin C intake and a reduced prevalence of cataracts (i.e., when comparing those above P95 for vitamin C intake with those below P5; (OR = 0.08; Cl: 0.01–0.75, P 0.05). Among subjects with cataracts, 12.1% had vitamin C intakes of < 61 mg/day (P10) and only 2.2% had intakes of > 183 mg/day (P95) (p < 0.01). Subjects who consumed > 3290 μg/day (P95) of lutein were less likely to have cataracts (OR = 0.086; Cl: 0.007–1.084; p < 0.05) than those whose consumption was < 256 μg/day (P5). In men, high intakes of zeaxanthin seemed to provide a protective effect against the problem (OR = 0.96; Cl: 0.91–0.99; p < 0.05). The results suggest an association exists between exposure to sunlight and the development of cataracts, and that vitamin C, lutein, and zeaxanthin offer some protection against this disorder.
Responses to Two Weight-loss Programs Based on Approximating the Diet to the Ideal: Differences Associated with Increased Cereal or Vegetable Consumption
Authors: Ortega  , Rodríguez-Rodríguez  , Aparicio  , Marín-Arias  , López-Sobaler
Published: March 2007

The fight against excess weight and obesity is a health priority. The aim of this study was to analyze the anthropometric changes induced by two weight control programs based on approximating the diet to the theoretical ideal (increasing the consumption of foods with the largest differences between the recommended and observed intakes: cereals and vegetables – for which a minimum of 6 and 3 servings/day are recommended, respectively). The study subjects were 57 Spanish women with a body-mass index (BMI) of 24–35 kg/m², all of whom were randomly assigned to one of two slightly hypocaloric diets for a six-week period: diet V, in which the consumption of greens and vegetables was increased, or diet C, in which the consumption of cereals was increased. Dietetic and anthropometric data were collected at the start of the study and again at two and six weeks. The dietary intervention approximated the subjects’ energy provision from proteins, fats, and carbohydrates to those recommended. The Healthy Eating Index (HEI) improved with both diets. Reductions in body weight, BMI, and the amount of body fat (kg) were also achieved with both diets. Weight loss was 1.56 ± 0.93 kg and 1.02 ± 0.55 kg at two weeks with diet C and V respectively, and 2.8 ± 1.4 kg and 2.0 ± 1.3 kg at six weeks (p < 0.05). Approximating the diet to the theoretical ideal by increasing the consumption of vegetables or cereals may therefore be of use in weight control. In terms of weight loss and the improvement of the diet quality (energy profile and HEI), diet C was significantly more effective than diet V.
Nitric acid particles in cold thick ice clouds observed at global scale: Link with lightning, temperature, and upper tropospheric water vapor
Authors: Chepfer H. , Minnis P. , Dubuisson P. , Chiriaco M. , Sun‐Mack S. , Rivière E. D.
Published: March 2007

Signatures of nitric acid particles (NAP) in cold thick ice clouds have been derived from satellite observations. Most NAP are detected in the tropics (9 to 20% of clouds with T < 202.5 K). Higher occurrences were found in the rare midlatitudes very cold clouds. NAP occurrence increases as cloud temperature decreases, and NAP are more numerous in January than July. Comparisons of NAP and lightning distributions show that lightning seems to be the main source of the NOx, which forms NAP in cold clouds over continents. Qualitative comparisons of NAP with upper tropospheric humidity distributions suggest that NAP may play a role in the dehydration of the upper troposphere when the tropopause is colder than 195 K.
Ozone climatological profiles for satellite retrieval algorithms
Authors: McPeters Richard D. , Labow Gordon J. , Logan Jennifer A.
Published: March 2007

A new altitude‐dependent ozone climatology has been produced for use with the version 8 Total Ozone Mapping Spectrometer (TOMS) and Solar Backscatter Ultraviolet retrieval algorithms. The climatology consists of monthly average ozone profiles for 10° latitude zones covering altitudes from 0 to 60 km (in Z* pressure altitude coordinates). The climatology was formed by combining data from Stratospheric Aerosol and Gas Experiment II (SAGE II; 1988–2001) or Microwave Limb Sounder (MLS; 1991–1999) with data from balloon sondes (1988–2002). Ozone below 10 km is based on balloon sondes, whereas ozone at 19 km and above is based on SAGE II measurements. When SAGE data are not available (at high latitudes), MLS data are used. The ozone climatology in the southern hemisphere and tropics has been greatly improved in recent years by the addition of a large number of balloon sonde measurements made under the Southern Hemisphere Additional Ozonesondes program. The new climatology better represents the seasonal behavior of ozone in the troposphere, including the known hemispheric asymmetry, and in the upper stratosphere. A modification of this climatology was used for the TOMS version 8 retrieval that includes total ozone dependence, which is important in the lower stratosphere. Comparisons of TOMS ozone with ground stations show improved accuracy over previous TOMS retrievals due in part to the new climatology.
Friction of drill bits under Martian pressure
Authors: Zacny K. A. , Cooper G. A.
Published: March 2007

Frictional behavior was investigated for two materials that are good candidates for Mars drill bits: Diamond Impregnated Segments and Polycrystalline Diamond Compacts (PDC). The bits were sliding against dry sandstone and basalt rocks under both Earth and Mars atmospheric pressures and also at temperatures ranging from subzero to over 400 °C. It was found that the friction coefficient dropped from approximately 0.16 to 0.1 as the pressure was lowered from the Earth's pressure to Mars' pressure, at room temperature. This is thought to be a result of the loss of weakly bound water on the sliding surfaces. Holding the pressure at 5 torr and increasing the temperature to approximately 200°C caused a sudden increase in the friction coefficient by approximately 50%. This is attributed to the loss of surface oxides. If no indication of the bit temperature is available, an increase in drilling torque could be misinterpreted as being caused by an increase in auger torque (due to accumulation of cuttings) rather than being the result of a loss of oxide layers due to elevated bit temperatures. An increase in rotational speed (to allow for clearing of cuttings) would then cause greater frictional heating and would increase the drilling torque further. Therefore it would be advisable to monitor the bit temperature or, if that is not possible, to include pauses in drilling to allow the heat to dissipate. Higher friction would also accelerate the wear of the drill bit and in turn reduce the depth of the hole.
Effect of shock on the magnetic properties of pyrrhotite, the Martian crust, and meteorites
Authors: Louzada Karin L. , Stewart Sarah T. , Weiss Benjamin P.
Published: March 2007

We performed planar shock recovery experiments on natural pyrrhotite at pressures up to 6.9 GPa. We find that high‐field isothermal remanent magnetization in pyrrhotite is demagnetized up to 90% by shock due to preferential removal of low coercivity components of magnetization. Contrary to static experiments, we do not observe complete demagnetization. Post shock permanent changes in magnetic properties include increasing saturation isothermal remanent magnetization, bulk coercivity and low‐temperature memory, and changes in squareness of hysteresis. These changes are consistent with an increase in the volume fraction of single domain grains. The lack of magnetic anomalies over large Martian impact basins is not expected to be solely due to shock demagnetization of the crust. We find that pyrrhotite‐bearing rocks and meteorites can retain records of Martian magnetic fields even if shocked to pressures approaching 7 GPa. However, some paleointensity techniques may underestimate this field.
Dominant impact of residential wood burning on particulate matter in Alpine valleys during winter
Authors: Szidat Sönke , Prévôt André S. H. , Sandradewi Jisca , Alfarra M. Rami , Synal Hans‐Arno , Wacker Lukas , Baltensperger Urs
Published: March 2007

Within the project AEROWOOD (Aerosols from wood burning versus other sources), particulate matter was collected at two Swiss Alpine valleys during winter. Apportionment of aerosols from transit traffic and residential wood burning was performed using radiocarbon (14C) determinations of the organic carbon (OC) and elemental carbon (EC) fractions. On daily average, 88% and 65% of the total carbonaceous matter (including all other atoms than carbon) originated from non‐fossil sources inside and outside of the village, respectively, which is mainly attributed to wood burning. These proportions were generally higher during the evening compared to morning hours, when traffic intensity waned and heating activities increased. 14C measurements of EC indicated episodes of both nearly pure traffic and wood‐burning sources, respectively, of which the latter extreme has not been observed for EC under ambient conditions before. Results show that regulatory measures for the improvement of air quality must consider residential wood burning as an important source even in industrialized countries.
Effects of lightning NOx production during the 21 July European Lightning Nitrogen Oxides Project storm studied with a three‐dimensional cloud‐scale chemical transport model
Authors: Ott Lesley E. , Pickering Kenneth E. , Stenchikov Georgiy L. , Huntrieser Heidi , Schumann Ulrich
Published: March 2007

The 21 July 1998 thunderstorm observed during the European Lightning Nitrogen Oxides Project (EULINOX) project was simulated using the three‐dimensional Goddard Cumulus Ensemble (GCE) model. The simulation successfully reproduced a number of observed storm features including the splitting of the original cell into a southern cell which developed supercell characteristics and a northern cell which became multicellular. Output from the GCE simulation was used to drive an offline cloud‐scale chemical transport model which calculates tracer transport and includes a parameterization of lightning NOx production which uses observed flash rates as input. Estimates of lightning NOx production were deduced by assuming various values of production per intracloud and production per cloud‐to‐ground flash and comparing the results with in‐cloud aircraft observations. The assumption that both types of flashes produce 360 moles of NO per flash on average compared most favorably with column mass and probability distribution functions calculated from observations. This assumed production per flash corresponds to a global annual lightning NOx source of 7 Tg N yr−1. Chemical reactions were included in the model to evaluate the impact of lightning NOx on ozone. During the storm, the inclusion of lightning NOx in the model results in a small loss of ozone (on average less than 4 ppbv) at all model levels. Simulations of the chemical environment in the 24 hours following the storm show on average a small increase in the net production of ozone at most levels resulting from lightning NOx, maximizing at approximately 5 ppbv day−1 at 5.5 km. Between 8 and 10.5 km, lightning NOx causes decreased net ozone production.
Tropical warming and intermittent cooling during the Cenomanian/Turonian oceanic anoxic event 2: Sea surface temperature records from the equatorial Atlantic
Authors: Forster Astrid , Schouten Stefan , Moriya Kazuyoshi , Wilson Paul A. , Sinninghe Damsté Jaap S.
Published: March 2007

Oceanic anoxic event 2 (OAE‐2) occurring during the Cenomanian/Turonian (C/T) transition is evident from a globally recognized positive stable carbon isotopic excursion and is thought to represent one of the most extreme carbon cycle perturbations of the last 100 Myr. However, the impact of this major perturbation on and interaction with global climate remains unclear. Here we report new high‐resolution records of sea surface temperature (SST) based on TEX86 and δ18O of excellently preserved planktic foraminifera and stable organic carbon isotopes across the C/T transition from black shales located offshore Suriname/French Guiana (Demerara Rise, Ocean Drilling Program Leg 207 Site 1260) and offshore Senegal (Cape Verde Basin, Deep Sea Drilling Project Leg 41 Site 367). At Site 1260, where both SST proxy records can be determined, a good match between conservative SST estimates from TEX86 and δ18O is observed. We find that late Cenomanian SSTs in the equatorial Atlantic Ocean (≥33°C) were substantially warmer than today (∼27°–29°C) and that the onset of OAE‐2 coincided with a rapid shift to an even warmer (∼35°–36°C) regime. Within the early stages of the OAE a marked (∼4°C) cooling to temperatures lower than pre‐OAE conditions is observed. However, well before the termination of OAE‐2 the warm regime was reestablished and persisted into the Turonian. Our findings corroborate the view that the C/T transition represents the onset of the interval of peak Cretaceous warmth. More importantly, they are consistent with the hypotheses that mid‐Cretaceous warmth can be attributed to high levels of atmospheric carbon dioxide (CO2) and that major OAEs were capable of triggering global cooling through the negative feedback effect of organic carbon‐burial‐led CO2 sequestration. Evidently, however, the factors that gave rise to the observed shift to a warmer climate regime at the onset of OAE‐2 were sufficiently powerful that they were only briefly counterbalanced by the high rates of carbon burial attained during even the most extreme interval of organic carbon burial in the last 100 Myr.
Additives in Water-borne Coatings
Authors:   NSPCC,   RSPCA
Published: March 2007

Additives in Water-borne Coatings covers both current technology and the future prognosis for the key additives used in water-borne coatings today. It brings together international experts to provide a comprehensive, practical overview of the field, its direction, and selection of key additives currently employed for in-depth treatment of their use, behaviour and scope by expert practitioners in those additives.
Northern Environment Predisposes Birches to Ozone Damage
Authors: Oksanen E. , Kontunen‐Soppela S. , Riikonen J. , Peltonen P. , Uddling J. , Vapaavuori E.
Published: March 2007

Abstract: Ozone sensitivity of silver birch (Betula pendula Roth) has been thoroughly investigated since early 1990′s in Finland. In our long‐term open‐field experiments the annual percentage reduction in basal diameter and stem volume increment were the best non‐destructive growth indicators for ozone impact when plotted against AOTX. Remarkable differences in defence strategies, stomatal conductance, and defence compounds (phenolics), clearly indicate that external exposure indices are ineffective for accurate risk assessment for birch. For flux‐based approaches, site‐specific values for gmax and gdark are necessary, and determinants for detoxification capacity, ageing of leaves, and cumulative ozone impact would be needed for further model development. Increasing CO2 seems to counteract negative ozone responses in birch, whereas exposure to springtime frost may seriously exacerbate ozone damage in northern conditions. Therefore, we need to proceed towards incorporating the most important climate change factors in any attempts for ozone risk assessment.
Effects of Long‐Term, Free‐Air Ozone Fumigation on the Cytokinin Content of Mature Beech Trees
Authors: Winwood J. , Pate A. E. , Price A. J. , Hanke D. E.
Published: March 2007

Abstract: We present the results of a study of the effects of chronic exposure to elevated ozone on the cytokinins of mature beech trees. Methods for analysing the cytokinin (CK) content of beech (Fagus sylvatica) were developed using seven enzyme‐linked immunosorbent assays (ELISAs). Samples taken during 2003 and 2004 from 10 mature beech trees in Kranzberg forest, 5 trees exposed to twice ambient ozone (2 × O3) by free‐air fumigation and 5 control trees (1 × O3), were analysed. In 2003 and 2004 the cytokinin content of leaf samples followed a similar seasonal pattern. In leaf samples, the content of aromatic types was equal to that of the isoprenoid types. In root samples, the level of aromatic types was no different from leaves, but that of the isoprenoid types was much higher. Leaf and phloem cytokinin contents for 2 × O3 trees were lower than for 1 × O3 at almost all sampling times. The effect of ozone was greater for leaves in the sun crown than for leaves in the shade crown. By contrast, the root and xylem contents of cytokinin for 2 × O3 trees were greatly elevated over the values for 1 × O3 trees early in the growing season. We propose that O3‐associated CK destruction in leaves reduces CK‐mediated root growth suppression. The resulting increases in root growth and ectomycorrhiza, reported by other groups in the Kranzberg forest project, are likely to be responsible for the increased CK export in xylem, although O3‐associated CK destruction in the leaves appears to nullify this increase.
O3 Flux‐Related Responsiveness of Photosynthesis, Respiration, and Stomatal Conductance of Adult Fagus sylvatica to Experimentally Enhanced Free‐Air O3 Exposure
Authors: Löw M. , Häberle K.‐H. , Warren C. R. , Matyssek R.
Published: March 2007

Abstract: Knowledge of responses of photosynthesis, respiration, and stomatal conductance to cumulative ozone uptake (COU) is still scarce, and this is particularly the case for adult trees. The effect of ozone (O3) exposure on trees was examined with 60‐year‐old beech trees (Fagus sylvatica) at a forest site of southern Germany. Trees were exposed to the ambient O3 regime (1 × O3) or an experimentally elevated twice‐ambient O3 regime (2 × O3). The elevated 2 × O3 regime was provided by means of a free‐air O3 canopy exposure system. The hypotheses were tested that (1) gas exchange is negatively affected by O3 and (2) the effects of O3 are dose‐dependent and thus the sizes of differences between treatments are positively related to COU. Gas exchange (light‐saturated CO2 uptake rate Amax, stomatal conductance gs, maximum rate of carboxylation Vcmax, ribulose‐1,5‐bisphosphate turnover limited rate of photosynthesis Jmax, CO2 compensation point CP, apparent quantum yield of net CO2 uptake AQ, carboxylation efficiency CE, day‐ and nighttime respiration) and chlorophyll fluorescence (electron transfer rate, ETR) were measured in situ on attached sun and shade leaves. Measurements were made periodically throughout the growing seasons of 2003 (an exceptionally dry year) and 2004 (a year with average rainfall). In 2004 Vcmax, Jmax, and CE were lower in trees receiving 2 × O3 compared with the ambient O3 regime (1 × O3). Treatment differences in Vcmax, Jmax, CE were rather small in 2004 (i.e., parameter levels were lower by 10 ‐ 30 % in 2 × O3 than 1 × O3) and not significant in 2003. In 2004 COU was positively correlated with the difference between treatments in Amax, gs, and ETR (i.e., consistent with the dose‐dependence of O3's deleterious effects). However, in 2003, differences in Amax, gs, and ETR between the two O3 regimes were smaller at the end of the dry summer 2003 (i.e., when COU was greatest). The relationship of COU with effects on gas exchange can apparently be complex and, in fact, varied between years and within the growing season. In addition, high doses of O3 did not always have significant effects on leaf gas exchange. In view of the key findings, both hypotheses were to be rejected.
Gas Exchange and Antioxidative Compounds in Young Beech Trees under Free‐Air Ozone Exposure and Comparisons to Adult Trees
Authors: Herbinger K. , Then C. , Haberer K. , Alexou M. , Löw M. , Remele K. , Rennenberg H. , Matyssek R. , Grill D. , Wieser G. , Tausz M.
Published: March 2007

Abstract: Three‐year‐old beech (Fagus sylvatica) seedlings growing in containers were placed into the sun and shade crown of a mature beech stand exposed to ambient (1 × O3) and double ambient (2 × O3) ozone concentrations at a free‐air exposure system (“Kranzberg Forst”, Germany). Pigments, α‐tocopherol, glutathione, ascorbate, and gas exchange were measured in leaves during 2003 (a drought year) and 2004 (an average year). Sun‐exposed seedlings showed higher contents of antioxidants, xanthophylls, and β‐carotene and lower contents of chlorophyll, α‐carotene, and neoxanthin than shade‐exposed seedlings. In 2003 sun‐exposed seedlings showed higher contents of carotenoids and total glutathione and lower net photosynthesis rates (Amax) compared to 2004. O3 exposure generally affected the content of chlorophyll, the xanthophyll cycle, and the intercellular CO2 concentration (ci). Seedlings differed from the adjacent adult trees in most biochemical and physiological parameters investigated: Sun exposed seedlings showed higher contents of α‐tocopherol and xanthophylls and lower contents of ascorbate, chlorophyll, neoxanthin, and α‐carotene compared to adult trees. Shade exposed seedlings had lower contents of xanthophylls, α‐carotene, and α‐tocopherol than shade leaves of old‐growth trees. In 2003, seedlings had higher Amax, stomatal conductance (gs), and ci under 2 × O3 than adult trees. The results showed that shade acclimated beech seedlings are more sensitive to O3, possibly due to a lower antioxidative capacity per O3 uptake. We conclude that beech seedlings are uncertain surrogates for adult beech trees.
Effects of Long‐Term Free‐Air Ozone Fumigation on δ15N and Total N in Fagus sylvatica and Associated Mycorrhizal Fungi
Authors: Haberer K. , Grebenc T. , Alexou M. , Gessler A. , Kraigher H. , Rennenberg H.
Published: March 2007

Abstract: Patterns of nitrogen (N) isotope composition (δ15N) and total N contents were determined in leaves, fine roots, root‐associated ectomycorrhizal fungi (ECM) of adult beech trees (Fagus sylvatica), and soil material under ambient (1 × O3) and double ambient (2 × O3) atmospheric ozone concentrations over a period of two years. From fine root to leaf material δ15N decreased consecutively. Under enhanced ozone concentrations total N was reduced in fine roots and δ15N showed a decrease in roots and leaves. In the soil and in most types of mycorrhizae, δ15N and total N were not altered due to ozone fumigation. The number of vital ectomycorrhizal root tips increased and the mycorrhizal community structure changed in 2 × O3. Simultaneously, the specific rate of inorganic N‐uptake by the roots was reduced under the double ozone regime. From these results it is assumed that 2 × O3 changes N‐nutrition of the trees at the level of N‐acquisition, as indicated by enhanced mycorrhizal root tip density, altered mycorrhizal species composition, and reduced specific N‐uptake rates.
Modelling Ozone Effects on Adult Beech Trees through Simulation of Defence, Damage, and Repair Costs: Implementation of the CASIROZ Ozone Model in the ANAFORE Forest Model
Authors: Deckmyn G. , Op de Beeck M. , Löw M. , Then C. , Verbeeck H. , Wipfler P. , Ceulemans R.
Published: March 2007

Abstract: Ozone affects adult trees significantly, but effects on stem growth are hard to prove and difficult to correlate with the primary sites of ozone damage at the leaf level. To simulate ozone effects in a mechanistic way, at a level relevant to forest stand growth, we developed a simple ozone damage and repair model (CASIROZ model) that can be implemented into mechanistic photosynthesis and growth models. The model needs to be parameterized with cuvette measurements on net photosynthesis and dark respiration. As the CASIROZ ozone sub‐model calculates effects of the ozone flux, a reliable representation of stomatal conductance and therefore ozone uptake is necessary to allow implementation of the ozone sub‐model. In this case study the ozone sub‐model was used in the ANAFORE forest model to simulate gas exchange, growth, and allocation. A preliminary run for adult beech (Fagus sylvatica) under different ozone regimes at the Kranzberg forest site (Germany) was performed. The results indicate that the model is able to represent the measured effects of ozone adequately, and to distinguish between immediate and cumulative ozone effects. The results further help to understand ozone effects by distinguishing defence from damage and repair. Finally, the model can be used to extrapolate from the short‐term results of the field study to long‐term effects on tree growth. The preliminary simulations for the Kranzberg beech site show that, although ozone effects on yearly growth are variable and therefore insignificant when measured in the field, they could become significant at longer timescales (above 5 years, 5 % reduction in growth). The model offers a possible explanation for the discrepancy between the significant effects on photosynthesis (10 to 30 % reductions simulated), and the minor effects on growth. This appears to be the result of the strong competition and slow growth of the Kranzberg forest, and the importance of stored carbon for the adult beeches (by buffering effects on carbon gain). We finally conclude that inclusion of ozone effects into current forest growth and yield models can be an important improvement into their overall performance, especially when simulating younger and less dense forests.
Free‐Air Exposure Systems to Scale up Ozone Research to Mature Trees
Authors: Karnosky D. F. , Werner H. , Holopainen T. , Percy K. , Oksanen T. , Oksanen E. , Heerdt C. , Fabian P. , Nagy J. , Heilman W. , Cox R. , Nelson N. , Matyssek R.
Published: March 2007

Abstract: Because seedlings and mature trees do not necessarily respond similarly to O3 stress, it is critically important that exposure systems be developed that allow exposure of seedlings through to mature trees. Here we describe three different O3 Free‐Air Exposure Systems that have been used successfully for exposure at all growth stages. These systems of spatially uniform O3 release have been shown to provide reliable O3 exposure with minimal, if any, impact on the microclimate. This methodology offers a welcome alternative to chamber studies which had severe space constraints precluding stand or community‐level studies and substantial chamber effects on the microclimate and, hence physiological tree performance.
Synopsis of the CASIROZ Case Study:CarbonSink Strength ofFagus sylvaticaL. in a Changing Environment ‐ ExperimentalRisk Assessment of Mitigation by ChronicOzone Impact
Authors: Matyssek R. , Bahnweg G. , Ceulemans R. , Fabian P. , Grill D. , Hanke D. E. , Kraigher H. , Oβwald W. , Rennenberg H. , Sandermann H. , Tausz M. , Wieser G.
Published: March 2007

Abstract:Databases are needed for the ozone (O3) risk assessment on adult forest trees under stand conditions, as mostly juvenile trees have been studied in chamber experiments. A synopsis is presented here from an integrated case study which was conducted on adultFagus sylvaticatrees at a Central‐European forest site. Employed was a novel free‐air canopy O3fumigation methodology which ensured a whole‐plant assessment of O3sensitivity of the about 30 m tall and 60 years old trees, comparing responses to an experimental 2 × ambient O3regime (2 × O3, max. 150 nl O3l‐1) with those to the unchanged 1 × ambient O3regime (1 × O3= control) prevailing at the site. Additional experimentation on individual branches and juvenile beech trees exposed within the forest canopy allowed for evaluating the representativeness of young‐tree and branch‐bag approaches relative to the O3sensitivity of the adult trees. The 2 × O3regime did not substantially weaken the carbon sink strength of the adult beech trees, given the absence of a statistically significant decline in annual stem growth; a 3 % reduction across five years was demonstrated, however, through modelling upon parameterization with the elaborated database. 2 × O3did induce a number of statistically significant tree responses at the cell and leaf level, although the O3responsiveness varied between years. Shade leaves displayed an O3sensitivity similar to that of sun leaves, while indirect belowground O3effects, apparently mediated through hormonal relationships, were reflected by stimulated fine‐root and ectomycorrhizal development. Juvenile trees were not reliable surrogates of adult ones in view of O3risk assessment. Branch sections enclosed in (climatized) cuvettes, however, turned out to represent the O3sensitivity of entire tree crowns. Drought‐induced stomatal closure decoupled O3intake from O3exposure, as in addition, also the “physiologically effective O3dose” was subject to change. No evidence emerged for a need to lower the “Critical Level for Ozone” in risk assessment of forest trees, although sensitive tree parameters did not necessarily reflect a linear relationship to O3stress. Exposure‐based concepts tended to overestimate O3risk under drought, which is in support of current efforts to establish flux‐related concepts of O3intake in risk assessment.
An Atom is Trapped by the Field of Just One Photon
Authors: Levi Barbara Goss
Published: March 2007

Researchers have been pushing atoms around with laser beams for many years, cooling them to record low temperatures and capturing them in confined spaces. Most such efforts require many photons. The field of a single photon is not generally strong enough to corral an atom—unless, that is, the light field is enhanced by confinement within a tiny cavity and the atom enters at a crawl. Then the coupling energy of the atom to the field can exceed the atom's kinetic energy, and the atom can become ensnared. A group from Caltech and the University of Auckland, and also a group at the Max Planck Institute for Quantum Optics in Garching, Germany, recently created the required conditions by combining cavity quantum electrodynamics with laser trapping and cooling; both groups succeeded in confining single atoms within optical cavities with an average of one photon in the cavity.
Our Knowledge of G Gets Worse, Then Better
Authors: Schwarzschild Bertram
Published: March 2007

The precision with which we know a fundamental constant usually gets better with the passing years. Just the opposite, however, was happening recently to G, Newton's gravitational constant. In 1987, CODATA, the international arbiter of metrology, was quoting an uncertainty of ±128 parts per million for G, the most poorly known of the fundamental constants. But then things got even worse. Several recent measurements have given values many standard deviations outside these limits, forcing CODATA to increase its assigned uncertainty to ±1500 ppm for the latest compilation.
Phase-Sensitive X-Ray Imaging
Authors: Fitzgerald Richard
Published: March 2007

The basic principles of x-ray image formation and interpretation in radiography have remained essentially unchanged since Röntgen first discovered x rays over a hundred years ago. The conventional approach relies on x-ray absorption as the sole source of contrast and draws exclusively on ray or geometrical optics to describe and interpret image formation. This approach ignores another, potentially more useful source of contrast—phase information. Phase-sensitive techniques, which can be understood using wave optics rather than ray optics, offer ways to augment or complement standard absorption contrast by incorporating phase information.
The Heat Flow through Nanoscale Wires Faces a Fundamental Limit
Authors: Levi Barbara Goss
Published: March 2007

If a conducting wire is sufficiently narrow, the electrical conductance through it is quantized, increasing in steps of 2e2/h with the width of the wire. Does an analogous quantization apply to another type of transport—the conduction of heat by phonons? The theoretical answer is “yes.” A narrow, thermally insulating wire should be able to carry no more heat per mode than g0 = π2k2T/3h, where k is Boltz-mann's constant, T is the temperature and h is Planck's constant.
Titanium Carbide Nanocrystals Shed Light on Late Phase of Stellar Lifecycle
Authors: Day Charles
Published: March 2007

By January 2006, NASA's Stardust spacecraft will have orbited the Sun three times and spent almost seven years trawling for interplanetary dust. On the sixteenth of that month, if all goes according to plan, a washbasin-sized capsule containing the netted dust will separate from the spacecraft, make its way toward Earth, and land softly in the Utah desert.
Two Satellites Observe Details of Ocean-Atmosphere Coupling
Authors: Day Charles
Published: March 2007

Winds drive ocean circulations, which, in turn, establish the sea surface temperature (SST) gradients that generate the atmospheric pressure to drive winds. Identifying and explaining the close coupling of ocean and atmosphere—its causes and effects, its feedback mechanisms—is a formidable challenge. In few locations is this goal more daunting than in the eastern tropical Pacific, the site of El Niño's and La Niña's biggest temperature anomalies. Here, the circulations of ocean and atmosphere are complicated by the coastal boundary, vigorous atmospheric convection, the convergence of northern and southern hemisphere trade winds, and the change of sign of the Coriolis force at the equator.
The Physics of the Sun and the Gateway to the Stars
Authors: Parker Eugene N.
Published: March 2007

A pedestrian star like the Sun is, in actuality, a physics laboratory we could never build. The Sun is basically a thermonuclear core enclosed in an opaque shroud that insulates the high temperature (107 K, or 1 keV) from the cold universe outside. The core is brighter than ten supernovas at maximum light, but the enclosing shroud turns back all but one part in 2×1011 of the thermal radiation, which is largely x rays of 10-50 nm wavelength. We see only the miniscule 4×1026 J/s that leak out. The outward journey of the energy from the core to the surface takes about a million years, illustrating again the immense opacity and thermal capacity of the shroud.
The Origins of Mathematical Physics: New Light on an Old Question
Authors: Netz Reviel
Published: March 2007

Imagine that you have to start science from scratch. Upon what disciplines should you draw? Philosophy, for instance, discusses the nature of time, space, and reality. Religion, too, tries to make sense of the world as a whole; and so, sometimes, does literature. Several disciplines—for example, biology and medicine—deal with special and highly significant features of the world. Such are the most natural ways to begin thinking about the world, and, in fact, most cultures make sense of their world through a combination of such intellectual resources. Mathematics, in comparison, appears like a non-starter. Here is a theory dealing with abstract objects, aiming at internal coherence rather than at connection to any external reality. All cultures develop some ways of dealing with calculation and measurement, and in some societies, a more abstract discipline, a “mathematics,” may also emerge. But it is a peculiarity of the modern world to take this abstract discipline as the cornerstone for science.
Researchers Can Now Vary the Atomic Interactions in a Bose–Einstein Condensate
Authors: Levi Barbara Goss
Published: March 2007

Bose–Einstein condensates (BECs) were formed five years ago from rubidium-87 and sodium atoms, whose interactions are repulsive. BECs were also formed from lithium-7 atoms, which attract one another. (See the article by Wolfgang Ketterle in PHYSICS TODAY, December 1999, page 30.) Now researchers in Boulder, Colorado, have created a single condensate of rubidium-85 atoms, which can be taken continuously from the repulsive to the attractive regimes. The experimenters can vary the strength of the interaction between the atoms in their condensate by a factor of 100 or more—and even flip its sign—by changing the external magnetic field. The ability to tune the interactions of a condensate opens the door to systematic explorations of atomic behavior in new regimes.
An Optical Spoon Stirs Up Vortices in a Bose–Einstein Condensate
Authors: Fitzgerald Richard
Published: March 2007

Since the early days of Bose–Einstein condensates (BECs) in atomic gases, comparisons have been drawn to the other familiar bosonic systems: liquid helium-4 and the Cooper pairs of superconductors. Two of the early questions asked of BECs were whether they had similar coherence properties and whether they were superfluids. In He4, it is rather difficult to study properties of the condensate, such as the condensate fraction, whereas the measurement of superfluidity is fairly straightforward. The opposite has proved true for atomic condensates: The condensate fraction as a function of temperature was found early on, but only recently has their superfluidity been placed on firm footing (see PHYSICS TODAY, November 1999, page 17).
Physicists in the New Era of Electronic Publishing
Authors: Langer James
Published: March 2007

Some of my colleagues in Santa Barbara—the string theorists, for example, and several of my coworkers in condensed matter theory as well—insist that they don't need The Physical Review. For research purposes, they don't need refereed print journals at all. They are producing remarkable results this way, so I take them very seriously.
Dendritic Signals Start Out Stronger When They Have Farther to Go
Authors: Day Charles
Published: March 2007

The trillion or so neurons in our brains are input-output devices. Feeding each neuron with information is a tree-like body of fine filaments called dendrites, whose trunk originates at the neuron's cell body or soma. Also attached to the soma is the axon, which carries the processed information to other cells—mostly the dendrites of other neurons via junctions called synapses.
Antiproton Research Resumes at CERN
Authors: Levi Barbara Goss
Published: March 2007

Experiments designed to probe differences between matter and antimatter using low-energy antiprotons have been on hold since CERN shut down its Low-Energy Antiproton Ring (LEAR) in December 1996. But the progress made at LEAR motivated the construction at CERN of a $5 million new facility, the Antiproton Decelerator (AD) (see PHYSICS TODAY, March 1996, page 17; November 1996, page 9; and May 1997, page 19). The photo shows the dipole (red) and quadrupole (blue) magnets in a section of the new ring. Antiprotons enter from the transfer line on the right.
Physics in Latin America Comes of Age
Authors: Morán-López José Luis
Published: March 2007

At the end of the 20th century, a large “science gap” still exists between Latin America and the developed countries of the North. One major reason for this disparity is economic: Poor economic conditions in most Latin American countries have seriously restricted their capability to invest in science and technology. However, the rich natural resources of the region—including oil, copper, nickel, cobalt, and other minerals—provide a solid economic base, and many countries are following the examples of Brazil, Mexico, and Argentina in recognizing that scientific research and technological development are necessary to achieve social and cultural progress. At present, prospects look good for growth in science and technology during the next century.
Solid-State NMR Reveals Key Structural Features of Membrane Transport Proteins
Authors: Day Charles
Published: March 2007

Only small neutral molecules can pass unaided through cell membranes. Other kinds of particles—ions that mediate neural signaling, sugars that provide energy, amino acids that form proteins, and so on—enter and leave cells through specialized molecular portals known collectively as membrane transport proteins. To do their vital jobs, these proteins must recognize and grant passage, when required, to only one kind of molecule. And if getting that molecule into or out of a cell involves pushing against an electrical or concentration gradient, the transport protein has to marshal the necessary energy.
Physics in the Whirlwind of Optical Communications
Authors: Thomas Gordon A. , Ackerman David A. , Prucnal Paul R. , Cooper S. Lance
Published: March 2007

Technology is providing people all over the world with much better ways of communicating than ever before, and the winds of change have whipped up the desire to exchange more of everything from messages to movies. This demand for more bandwidth in communications is powering a whirlwind of changes in technology. As Dorothy said to her dog in the Land of Oz, “Toto, I have a feeling that we're not in Kansas anymore.”