bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of metaphor in Darwin and the implications for teaching evolution
Authors: Pramling Niklas
Published: September 2008

This article is about the role of metaphor in scientific knowledge formation and reasoning. These issues are studied by means of an example of the theory of evolution through natural selection. The premise is that the theory of evolution contains a set of problems regarding metaphor. A second premise is that these problems have to be handled in one way or another when trying to learn, explain, or discuss the theory. How metaphor plays a role in Darwin's writings is analyzed through examples taken from On the Origin of Species. Which metaphors are used by Darwin and which problems do they solve and raise, respectively? It is shown how Darwin uses a variety of metaphors, and that he grapples with this issue. The findings are discussed in terms of the implications for teaching evolutionary theory. Some inherent difficulties in learning the theory of evolution, and more generally abstract complex scientific knowledge, are discussed. © 2008 Wiley Periodicals, Inc. Sci Ed 93: 535–547, 2009
A scale to measure non‐traumatic military operational stress
Authors: Deans Carolyn , Byrne Don G.
Published: September 2008

Military operations involve both traumatic and non‐traumatic stressors. The authors developed a scale to measure non‐traumatic operational stressors. In Study 1, a list of stressors identified by military personnel was compared across responses from two operations in East Timor. Exploratory factor analysis yielded three similar factors for each dataset. A confirmatory factor analysis on the combined data determined item placement. Item analysis then reduced the questionnaire to 22 items. In Study 2, the questionnaire was administered to personnel from operations in the Middle East. Correlations with similar scales measured the content validity of the three subscales (work concerns, operational concerns and separation concerns). The authors conclude the questionnaire is a robust measure of operational non‐traumatic stressors applicable across operations. Copyright © 2008 John Wiley & Sons, Ltd.
Differential expression of Fos and Zif268 in the nigrostriatal system after methamphetamine administration in a rat model of Parkinson's disease
Authors: Ishida Yasushi , Kawai Keiichi , Magata Yasuhiro , Ebihara Kosuke , Takeda Ryuichiro , Abe Hiroshi , Yoshimoto Mitsuyoshi , Hashiguchi Hiroyuki , Odagiri Kei , Matsuo Hisae , Nishimori Toshikazu
Published: September 2008

The goal of this study was to examine the topological specificity of methamphetamine‐induced activation of the immediate‐early gene proteins, Fos and Zif268, in the nigrostriatal system in a unilateral 6‐hydroxydopamine (6‐OHDA) rat model of Parkinson's disease with or without intrastriatal grafts of fetal ventral mesencephalon. Methamphetamine (3 mg/kg, i.p.) induced Fos‐like immunoreactivity (FLI) dominantly in the striatum and the globus pallidus (GP) on the intact side as well as in the substantia nigra pars reticulata (SNr) on the lesioned side in the 6‐OHDA rats. Lower levels of methamphetamine‐induced FLI in the striatum and GP on the lesioned side were restored by intrastriatal grafts which could completely suppress the methamphetamine‐induced rotation. In the striatum, a similar tendency could be observed between Fos and Zif268 immunoreactivity following methamphetamine. However, sparse immunoreactivity of Zif268 could be detected in the GP and SNr on both sides in the 6‐OHDA rats. Intrastriatal grafts had little influence on Zif268 expression in these two regions. The differential expression of Fos and Zif268 was observed among the three regions of the nigrostriatal system following methamphetamine in the 6‐OHDA rats. This may suggest that Fos and Zif268 therefore possess gene‐specific and region‐specific functions in the basal ganglia nuclei. Synapse 62:920–926, 2008. © 2008 Wiley‐Liss, Inc.
Analysis of linoleate and linolenate by isomerization with potassiumtertiary butoxide in mixtures oftertiary butanol and ethylene glycol dimethyl ether
Authors: Korver O. , Alderlieste E. T. , Boelhouwer C.
Published: September 2008

A simple spectrophotometric procedure is described for determining the content of linoleic and linolenic acid in natural oils. Isomerization is accomplished at 70C with potassiumtertiary butoxide (0.57 M) in 110 min. The absorptivities of linoleic acid (k233=86.9) and linolenic acid (k233=66.9 and k268=46.9) attain a maximum and remain constant thereafter.
Nuclear magnetic resonance determination of bacteriostats
Authors: Dietrich Martin W. , Keller Robert E.
Published: September 2008

A rapid high‐resolution NMR method has been developed for the determination of soap and detergent bacteriostats. The method can be used to identify six common commercial bacteriostats (3,4,4′‐trichlorocarbanilide; 3‐trifluoromethyl‐4,4′‐dichlorocarbanilide; 4′,5‐dibromosalicylanildie; 3,5‐dibromosalicylanilide; 3,4′,5‐tribromosalicylanilide; and ehxachlorophene) and all two‐component mixtures prepared from them. This method can also be used to determine the relative concentrations of these bacteriostats in all two‐component mixtures. The precision and accuracy of the method are estimated to be within 3% absolute.
Comparison of practical and laboratory laundering of some modern fabrics
Authors: Hunter R. T. , Kurgan C. R. , Marder H. L.
Published: September 2008

The detergency and redeposition characteristics of several modern fabrics were compared under laboratory and home‐laundering conditions. Good correlation was found between data from laboratory‐controlled practical washing and home laundry although washing in the home was uniformly poorer than in the laboratory. Polyester‐containing fabrics tend to gray by redeposition more than the other fabrics investigated, and the new Permanent‐Press fabrics seem more susceptible to redeposition than their untreated counterparts. A systematic screening of factors affecting the performance of these fabrics in the home laundry indicates that detergent underusage is the major factor for the failure of polyesters to perform as well as cotton in either laboratory or practical laundry screening.
The foam separation of colloidal ferric oxide with an anionic and a cationic surfactant
Authors: Grieves Robert B. , Bhattacharyya Dibakar
Published: September 2008

An experimental investigation is presented of the foam separation of colloidal ferric oxide over the pH range 3 to 12 by using an anionic and a cationic surfactant. A sol containing 1.67 mmole/ liter (93 mg/liter) of trivalent iron can be reduced in concentration to 0.09 mmole/liter by 0.17 mmole/liter dodecyl sodium sulfate (anionic) over pH 4.5 to 8; and to 0.18 mmole/liter by 0.17 mmole/liter ethylhexadecyldimethylammonium bromide (cationic) over pH 10 to 12. Soluble iron species produce poorer separations. Between pH 8 and pH 10 the charge of the colloid is reversed from positive to negative, and for an efficient separation a two‐step process should be used, first with an anionic surfactant and then with a cationic. The charge of the particulates has little effect on the foam separation of the surfactants although the presence of the particulates has a significant effect, as evidenced by residual surfactant concentrations and collapsed foam volumes.
A systematic characterization of the reversion flavor of soybean oil
Authors: Smouse Thomas H. , Chang Stephen S.
Published: September 2008

The volatile flavor compounds in a reverted soybean oil with a peroxide number of 4.3 meq/kg were isolated by a semicontinuous counter‐current vacuum steam‐distillation process, fractionated by repeated gas chromatography, and identified by infrared and mass spectrometry. A total of 71 compounds were identified, which included 19 acids, 39 nonacidic compounds, and 13 tentatively identified compounds. The acids consisted of eight normal saturated acids, nine ॅ,ॆ‐unsaturated acids, a branch‐chain acid, one hydroxy acid, two keto acids, three lactones, and one aromatic acid. The nonacidic compounds consisted of two esters, eight normal saturated aldehydes, two branched‐chain aldehydes, five 2‐enals, three dienals, eight ketones, eight alcohols, six hydrocarbons, and four aromatic compounds.

The mechanism of formation of the identified compounds indicated that they were mostly primary or secondary autoxidation products of the hydroperoxides of the unsaturated fatty esters. Since many of the identified compounds were produced from oleic and linoleic acids, it is doubtful that linolenic acid was solely responsible for the reversion flavor.

Of the compounds identified two are of unusual interest. They are 1‐decyne and 2‐pentyl furan. The former is the first acetylenic compound reported as the autoxidation products of unsaturated fatty esters which contained only double bonds. The latter imparts to an oil at concentrations of 5‐10 ppm a beany and grassy flavor reminiscent of that of a reverted soybean oil. Since this compound is postulated as being produced by the autoxidation of linolenic acid, it is suggested that the presence of linolenic acid catalyzes the autoxidation of linoleic acid and possibly alters the decomposition pattern of its hydroperoxides.
Air pollution regulation of nonvehicular, organic‐solvent emissions by Los Angeles Rule 66
Authors: Maher G. R.
Published: September 2008

In an effort to further their control of sources emitting organic solvents into the atmosphere, the Air Pollution Control District of Los Angeles County, Calif., successfully secured passage of Rule 66 into law July 28, 1966. Rule 66 specifically relates to the control of organic solvent emissions from stationary sources. This paper directs itself to a discussion of the technical aspects used by the Air Pollution Control District in establishing which organic solvents contribute most significantly to the formation of photomechanical smog, eye irritation, and ozone. It also draws attention to the very specific topography of Los Angeles County. And it suggests that air pollution control authorities elsewhere be made cognizant of this in establishing controls on organic solvent emissions in their localities, so as not to be unnecessarily harsh and restrictive.
Cardiologists' awareness and perceptions of guidelines for chronic heart failure. The ADDress your Heart survey
Authors: Erhardt Leif , Komajda Michel , Hobbs F.D. Richard , Soler‐Soler Jordi
Published: September 2008

Background:

Several surveys show that patients with chronic heart failure (CHF) are sub‐optimally managed and treatment guidelines are not implemented in clinical practice.

Aims:

To investigate awareness and perceptions of the 2005 European Society of Cardiology (ESC) guidelines for CHF.

Methods:

467 cardiologists from seven European countries completed an on‐line interview using a validated, semi‐structured questionnaire including questions about awareness and relevance of CHF guidelines. To assess agreement with ESC guidelines, three fictitious patient cases were presented and respondents' management choices compared with those of an expert panel based on the guidelines.

Results:

Awareness of CHF guidelines was high, with 98% aware of any guideline and 65% aware of ESC guidelines. ESC guidelines were considered relevant (51%) or very relevant (38%) for guiding treatment decisions. Up to 92% of respondents perceived that they adhered to the ESC guidelines. For the patient cases, ≤25% made treatment recommendations that completely matched those formulated by the expert panel. Respondents considered patient compliance (52%) and guideline complexity (46%) major barriers to implementation.

Conclusion:

Cardiologists reported high awareness of and a positive attitude towards ESC CHF guidelines. Provision of guidelines in a concise and accessible format is perceived as a key factor to improve implementation.
Schizophrenia as social discourse: How do people use their diagnosis for social action?
Authors: Haghighat Rahman
Published: September 2008

‘Schizophrenia’ can do things other than diagnose or stigmatize those so defined in that it can serve various forms of social action. Two hundred and fifty-eight randomly selected patients with an experience of schizophrenia and their relatives participated in the study of schizophrenia as social discourse. They used the diagnosis for political struggle and social leverage in such diverse forms as demonstration of the meaning of ‘a schizophrenic’, discursive intervention for ideological invitation, reclaiming personal worth (revalorization), solidarity with fellow patients and economic compensation. Despite the inherent value of the diagnosis in helping them get the right treatment, participants saw devaluing meaning in various designations for schizophrenia and, given choice, preferred certain formulations of the diagnosis over others in relation to their social discourse. To be effective, treatment models, service delivery and communication with patients must allow, interpret and incorporate their first person accounts (discourse) as a feature of their individuality and uniqueness in the therapeutic process. This is likely to increase their sense of wellbeing, empowerment and cooperation with the treatment.
The Importance of Having a Different Opinion Europeans and GM foods
Authors: Loner Enzo
Published: September 2008

Objectives. The article examines the opinions of Europeans concerning genetically modified (GM) foods. It first deals with the socio-cultural variables that favour acceptance of such products. It then analyses the minority of respondents who exhibit greater openness towards GM foods. Methods. Mokken Scale Analysis (MSA) is applied to 2002 Eurobarometer 58.0 data to construct an index of acceptance of GM foods. Results. The acceptance of GM foods is associated positively with trust in biotechnologies and negatively with concerns about the environment. The minority consisting of respondents in favour of GM foods possesses specific characteristics. Unlike the rest of the respondents, these principally consider the opportunity to spend less, the absence of fats, and the taste of foods. Conclusions. The analysis confirms that high education level does not favour acceptance of GM foods.
UNIFORM APPROXIMATION BY POLYNOMIAL, RATIONAL AND ANALYTIC FUNCTIONS
Authors: HONARY T. G. , MORADI S.
Published: September 2008

Let K and X be compact plane sets such that $K\subseteq X$. Let P(K) be the uniform closure of polynomials on K, let R(K) be the uniform closure of rational functions on K with no poles in K and let A(K) be the space of continuous functions on K which are analytic on int(K). Define P(X,K),R(X,K) and A(X,K) to be the set of functions in C(X) whose restriction to K belongs to P(K),R(K) and A(K), respectively. Let S0(A) denote the set of peak points for the Banach function algebra A on X. Let S and T be compact subsets of X. We extend the Hartogs–Rosenthal theorem by showing that if the symmetric difference SΔT has planar measure zero, then R(X,S)=R(X,T) . Then we show that the following properties are equivalent:

(i)

R(X,S)=R(X,T) ;

(ii)

$S\setminus T\subseteq S_0(R(X,S))$ and $T\setminus S\subseteq S_0(R(X,T))$;

(iii)

R(K)=C(K) for every compact set $K \subseteq S\Delta T$;

(iv)

$R(X,S \cap \overline {U})=R(X,T \cap \overline {U})$ for every open set U in ℂ ;

(v)

for every p∈X there exists an open disk Dp with centre p such that

We prove an extension of Vitushkin’s theorem by showing that the following properties are equivalent:

(i)

A(X,S)=R(X,T) ;

(ii)

$A(X,S \cap \overline {D})=R(X,T \cap \overline {D})$ for every closed disk $\overline {D}$ in ℂ ;

(iii)

for every p∈X there exists an open disk Dp with centre p such that
Drought tolerance assessment of African cowpea accessions based on stomatal behaviour and cell membrane stability
Authors: LABUSCHAGNE M. T. , VERHOEVEN R. , NKOUANESSI M.
Published: September 2008

In Sub-Saharan Africa, cowpea is well known for its ability to survive under conditions of water stress and it plays an important role in regions where drought is the factor most limiting to crop yield. In the present study, the drought tolerance levels of 20 African cowpea accessions from three countries were evaluated. A number of the genotypes showed drought tolerance, the merits of stomatal behaviour and cell membrane stability to assess drought tolerance was demonstrated. Damage to the cell membranes caused by drought was less in tolerant accessions. Stomatal opening was also better regulated; the opening was smaller under drought conditions, thus reducing transpiration (T). The wide range of drought tolerance observed among the accessions suggests the possibility of breeding drought-tolerant cultivars in cowpea. Drought-tolerant accessions included Bafoussam 1, M.66, Bafoussam 3, Hluhluwa, Bafoussam 4, Balen, Makueni, Bafoussam 2 and Okhalweni and these could be recommended to breeders as valuable material for drought tolerance improvement in cowpea.
Incidence of invasive pneumococcal disease in the Czech Republic and serotype coverage by vaccines, 1997–2006
Authors: MOTLOVA J. , BENES C. , KRIZ P.
Published: September 2008

We studied the incidence of invasive pneumococcal disease (IPD) in the Czech Republic by analysing two sources of data. The incidence of pneumococcal meningitis based on routine notification data varied between 0·4 and 0·6/100 000 population between 1997 and 2006. The incidence of IPD based on laboratory surveillance varied between 2·3 and 4·3/100 000 population between 2000 and 2006. The annual IPD incidence remained stable during the study period. Estimates of absolute IPD case-load in the entire country varied from 235 to 437 per year. The age-specific incidence was highest in the <1 year age group, reaching 4·3/100 000 for pneumococcal meningitis in routine notification and 15·7/100 000 for IPD in laboratory-based surveillance data, respectively. A total of 1236 Streptococcus pneumoniae isolates from cerebrospinal fluid and sterile body sites were investigated. The most frequent serotypes causing IPD in all ages were 3, 4, 14, 8 and 19F, accounting for 41·5% of all isolates. The most frequent serotypes by age group were: <1 year (6B and 19F); 1–4 years (14, 6B and 23F); 40–64 years (3, 8 and 4), and ⩾65 years (3, 4, 9N and 14). The coverage of serotypes in all age groups by pneumococcal vaccines ranged from 41·5% for 7-valent conjugate vaccine to 67·9% for 13-valent conjugate vaccine. The coverage of serotypes causing IPD is significantly different between infants/children and adults/elderly. PCV-7 coverage by age group was: <1 year (66·0%), 1–4 years (65·1%), 40–64 years (34·4%) and ⩾65 years (39·3%). Similar age differences between infants/children and adults/elderly were found in coverage by PCV-9, PCV-11 and PCV-13. The distribution of serotypes in the total population and individual age groups was stable during the period 2000–2006.
Sir Edward Coke Gets It Wrong? A Brief History of Consecration
Authors: Homfray Kenyon
Published: September 2008

In many modern works of ecclesiastical law, the Institutes of Sir Edward Coke are given as the authority for the consecration of buildings as places of public worship. For authority Coke relies on scriptural precedent. This paper suggests that, in fact, the origin of consecration as a legal precedent lies in pre-Christian Roman law.1
Golgi-mediated Transport of Seed Storage Proteins
Authors: Robinson David G. , Hinz Giselbert
Published: September 2008

The great majority of seed proteins that are stored in the vacuole prior to desiccation are transported via the Golgi apparatus. In this organelle they are separated from other products of the secretory pathway. Evidence is accumulating that the mechanism for segregation of storage proteins is different from that of soluble proteins destined for lytic vacuoles: it rarely seems to require short targeting propeptides at the N- or C-terminus. Instead, the three-dimensional conformation of the protein appears to be a critical factor, leading to self-assembly into osmiophilic aggregates. Also unusual is that this process starts immediately after entry into the Golgi apparatus, i.e. at thecis-cisternae, rather than at thetrans-pole where acid hydrolases are packaged into clathrin-coated vesicles. Storage protein aggregates accumulate into so-called “dense” vesicles at the periphery of the cisternae and are transported towards thetrans-pole of the Golgi apparatus by cisternal progression. Before the dense vesicles are released, clathrin-coated vesicles form at their surface; however, the function of the latter remains the object of speculation. In other eukaryotes, delivery of Golgi-derived lumenal products to the vacuole does not occur directly, but via a pre-vacuolar compartment. There is evidence that this is also the case for plants, and in developing pea cotyledons the pre-vacuolar compartment takes the form of a large multivesicular body. Ultimately this appears to fusein totowith the protein storage vacuole.
Vicia faba germination: Synchronized cell growth and localization of nucleolin and α-tubulin.
Authors: Fujikura Yuzo , Doležel Jaroslav , Cíhalíková Jarmira , Bögre Laszlo , Heberle-Bors Erwin , Hirt Heribert , Binarová Pavla
Published: September 2008

The first cell cycle ofVicia fabaL. seeds, which begins upon imbibition of dry seeds and is completed at the first mitosis after radicle protrusion, was characterised by the flow cytometry and immunodetection of nucleolin and tubulins in root tip meristems. Flow cytometry revealed highly synchronised profiles from the quiescent G1phase to the late G2phase, indicating uniform cell cycle progression within a root tip until the first mitosis. Using immunoblotting, nucleolin was detected in two distinct bands with the apparent molecular masses of 89 and 99 kD; the former was detected only in seeds imbibed at 4°C for 1 day whereas the latter was found at all stages examined, suggesting that the 89 kD nucleolin may be seed-specific. Unusual localization of nucleolin in cold-imbibed seeds, undetectable in half of the cells and present in nucleoplasm, was revealed by immunofluorescence microscopy. While α- and β-tubulin were detected at all stages and no significant changes in accumulation of the proteins were observed, few microtubules were detected at the beginning of germination when cells were still in the G1phase, suggesting that microtubules may be depolymerized in the dry seeds.
The discovery of compositional variation for the raffinose family of oligosaccharides in pea seeds
Authors: Jones D. A. , DuPont M. S. , Ambrose M. J. , Frias J. , Hedley C. L.
Published: September 2008

The raffinose family of oligosaccharides (RFO) is present in relatively high levels in grain legume seeds. They are considered to be antinutritional compounds because they are, at least in part, believed to be responsible for causing flatulence in humans, which is the single most important factor in deterring people from including more legume seeds in their diet. The RFO also have important functions within the plant. They serve as transport metabolites in many legumes and have been proposed to play a positive role in cold acclimatisation and in conferring desiccation tolerance during seed maturation. These responses to environmental stresses are believed to result from the RFO acting as protecting agents for membrane bound-proteins. We have screened 70 pea lines from the test array of the John Innes Pisum germplasm collection, and lines were selected which had unusual RFO composition. The soluble sugars within these lines were quantified using High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD), and variants were identified which were deficient in verbascose and one with a reduced level of raffinose. These selected lines are being used in a crossing programme designed to study the genetics of the RFO pathway and to produce new material to test the effect of specific RFO on the plant’s responses to the environment and on the diets of humans and animals.
Methanol, pectin and pectinesterase changes during soybean seed maturation
Authors: Koch James L. , Horbowicz Marcin , Obendorf Ralph L.
Published: September 2008

Methanol accumulates in maturing seeds, correlating with preharvest deterioration. Since the source of methanol may be from pectin de-methylation, methanol, cell wall uronic acid, pectin methyl esterification, pectinesterase (PE; EC 3.1.1.11) activity, and neutral sugar composition and partitioning of cell wall polysaccharides were determined during soybean (Glycine max[L.] Merrill) seed development, maturation, and desiccationin planta. Axis cell wall polysaccharides were more easily solubilized, richer in uronic acid, rhamnose, and xylose, and less rich in galactose than cotyledon cell wall polysaccharides. Methanol accumulated to 9.7 μg per two cotyledons and 0.5 μg per axis; total methanol decreased to 3 μg per two cotyledons during loss of green color. Total uronic acid increased from 0.12 to 0.27 mg per axis and 0.9 to 4 mg per cotyledon between 24 and 50 days after flowering (DAF). After loss of green color, pectin methyl esterification in axes increased from 7 to 24 mole% between 50 and 60 DAF but decreased to 14 mole%by 62 DAF in latter stages of seed desiccation. In cotyledons, methyl esterification ranged from 25 to 40 mole% and was 31 mole% after desiccation. PE activity increased 100 fold in axes, including a 30-fold increase in activity after loss of green color at 46 DAF. Cotyledon PE activity was 40-fold higher than in axes at 24 DAF, declined 75% by 56 DAF, and then increased 5 fold during desiccation. Pectin methyl de-esterification by PE is sufficient to be the sole source for methanol accumulation in seed tissues during development and maturation.
Use of Monte Carlo Modeling to Aid Interpretation and Quantification of the Low Energy-Loss Electron Yield at Low Primary Energies
Authors: Bonet Christopher , Pratt Andrew , El-Gomati Mohamed M. , Matthew Jim A.D. , Tear Steven P.
Published: September 2008

Experimental low-loss electron (LLE) yields were measured as a function of loss energy for a range of elemental standards using a high-vacuum scanning electron microscope operating at 5 keV primary beam energy with losses from 0 to 1 keV. The resulting LLE yield curves were compared with Monte Carlo simulations of the LLE yield in the particular beam/sample/detector geometry employed in the experiment to investigate the possibility of modeling the LLE yield for a series of elements. Monte Carlo simulations were performed using both the Joy and Luo [Joy, D.C. & Luo, S.,Scanning11(4), 176–180 (1989)] expression for the electron stopping power and recent tabulated values of Tanuma et al. [Tanuma, S. et al.,Surf Interf Anal37(11), 978–988 (2005)] to assess the influence of the more recent stopping power data on the simulation results. Further simulations have been conducted to explore the influence of sample/detector geometry on the LLE signal in the case of layered samples consisting of a thin C overlayer on an elemental substrate. Experimental LLE data were collected from a range of elemental samples coated with a thin C overlayer, and comparisons with Monte Carlo simulations were used to establish the overlayer thickness.
Modeling convection over arctic leads with LES and a non‐eddy‐resolving microscale model
Authors: Lüpkes C. , Gryanik V. M. , Witha B. , Gryschka M. , Raasch S. , Gollnik T.
Published: September 2008

Turbulent heat transport over inhomogeneous surfaces with sharp temperature discontinuities is investigated with a focus on the flow over leads in sea ice. The main goal consists in the development of a turbulence closure for a microscale atmospheric model resolving the integrated effect of plumes emanated from leads, but not the individual convective eddies. To this end, 10 runs are carried out with a large eddy simulation (LES) model simulating the flow over leads for springtime atmospheric conditions with near‐neutral inflow and a strong capping inversion. It is found that leads contribute to the stabilizing of the polar atmospheric boundary layer (ABL) and that strong countergradient fluxes of heat exist outside a core region of the plumes. These findings form the basis for the development of the new closure. It uses a new scaling with the internal ABL height and the characteristic vertical velocity for the plume region as the main governing parameters. Results of a microscale model obtained with the new closure agree well with the LES for variable meteorological forcing in case of lead orthogonal flow and for a fixed ABL height and lead width. The good agreement concerns especially the plume inclination, temperature, and heat fluxes as well as the relative contributions of gradient and countergradient transport of heat. A future more general closure should account, for example, for variable lead widths and wind directions. Results of the microscale model could be used to derive a future parameterization of the lead effect in large‐scale models.
Cloud processing of nitrate
Authors: Hayden K. L. , Macdonald A. M. , Gong W. , Toom‐Sauntry D. , Anlauf K. G. , Leithead A. , Li S.‐M. , Leaitch W. R. , Noone K.
Published: September 2008

The role of clouds in the transport and transformation of tropospheric pollutants was investigated through airborne measurements made out of Cleveland, Ohio, from 21 July to 18 August 2004, as part of the International Consortium for Atmospheric Research on Transport and Transformation 2004 program. Observations of gas‐phase nitrate, size‐resolved particulate nitrate, cloud water nitrate, and size‐distributed cloud residual nitrate are used to examine changes in the partitioning of nitrate from precloud to postcloud as a function of particle size. The [NO3−]/[SO42−] ratio was highest in the bulk cloud water and higher in the cloud droplet residuals compared with the below‐cloud aerosols. Most of the nitrate entered the cloud water as HNO3, and in 30% of 43 size distributions examined, the nitrate in the cloud droplets was found in residual particle sizes smaller than those of sulfate. Simulations from a trace gas‐aerosol‐cloud parcel model show that this size difference results from differences in the processes by which nitrate and sulfate enter cloud water. The transfer of HNO3 to cloud droplets is governed primarily by gas‐phase mass transfer to the droplets, leading to greater accumulation in the smaller, more numerous droplets with higher total surface area. In contrast, much of the sulfate in the cloud water is the result of nucleation scavenging, which distributes the sulfate mass toward slightly larger sizes. The extent of separation between nitrate and sulfate is dependent on the cloud base sulfate size distribution and the factors that govern both HNO3 and SO2 uptake, with subsequent S(IV) oxidation.
Effects of gas particle partitioning and aging of primary emissions on urban and regional organic aerosol concentrations
Authors: Shrivastava Manish K. , Lane Timothy E. , Donahue Neil M. , Pandis Spyros N. , Robinson Allen L.
Published: September 2008

Organic aerosols (OA) are a highly dynamic system dominated by both variable gas particle partitioning and chemical evolution; however, these phenomena are poorly represented in current air quality models. The chemical transport model Comprehensive Air‐Quality Model with extensions dealing with particulate matter (PMCAMx) was extended to investigate the effects of partitioning and photochemical aging of primary emissions on OA concentrations in the eastern United States during July 2001 and January 2002. In both the summer and the winter, much of the traditionally defined primary OA (POA) emissions evaporate, creating a large pool of low‐volatility organic vapors. During the summertime, photochemical aging of these vapors creates substantial oxygenated OA that is regionally distributed. Little production of oxygenated OA is predicted in the winter because oxidant levels are low. OA formed from the oxidation of low‐volatility vapors is most important in and around urban areas located in the northeast and midwest. In rural locations and throughout the southeast, traditional secondary OA (SOA) formed from biogenic precursors is predicted to be the dominant class of oxidized OA. PMCAMx can only reproduce the large fractional contributions of oxidized OA observed in the atmosphere if some of the POA in the model evaporates. Sensitivity analysis illustrates that the volatility distribution of the existing POA emissions and the amount of intermediate volatility compounds not accounted for in current inventories are key uncertainties. At an upper bound, better accounting for emissions of low‐volatility organics has the potential to increase summertime OA concentrations in northeastern and midwestern cities by as much as 50%.
A model for fluvial bedrock incision by impacting suspended and bed load sediment
Authors: Lamb Michael P. , Dietrich William E. , Sklar Leonard S.
Published: September 2008

A mechanistic model is derived for the rate of fluvial erosion into bedrock by abrasion from uniform size particles that impact the bed during transport in both bed and suspended load. The erosion rate is equated to the product of the impact rate, the mass loss per particle impact, and a bed coverage term. Unlike previous models that consider only bed load, the impact rate is not assumed to tend to zero as the shear velocity approaches the threshold for suspension. Instead, a given sediment supply is distributed between the bed and suspended load by using formulas for the bed load layer height, bed load velocity, logarithmic fluid velocity profile, and Rouse sediment concentration profile. It is proposed that the impact rate scales linearly with the product of the near‐bed sediment concentration and the impact velocity and that particles impact the bed because of gravitational settling and advection by turbulent eddies. Results suggest, unlike models that consider only bed load, that the erosion rate increases with increasing transport stage (for a given relative sediment supply), even for transport stages that exceed the onset of suspension. In addition, erosion can occur if the supply of sediment exceeds the bed load transport capacity because a portion of the sediment load is transported in suspension. These results have implications for predicting erosion rates and channel morphology, especially in rivers with fine sediment, steep channel‐bed slopes, and large flood events.
Why are climate models reproducing the observed global surface warming so well?
Authors: Knutti Reto
Published: September 2008

Climate models reproduce the observed surface warming better than one would expect given the uncertainties in radiative forcing, climate sensitivity and ocean heat uptake, suggesting that different models show similar warming for different reasons. It is shown that while climate sensitivity and radiative forcing are indeed correlated across the latest ensemble of models, eliminating this correlation would not strongly change the uncertainty range of long‐term temperature projections. However, since most models do not incorporate the aerosol indirect effects, model agreement with observations may be partly spurious. The incorporation of more detailed aerosol effects in future models could lead to inconsistencies between simulated and observed past warming, unless the effects are small or compensated by additional forcings. It is argued that parameter correlations across models are neither unexpected nor problematic if the models are interpreted as conditional on observations.
Observational evidence for asymmetric changes in tropospheric heights over Antarctica on decadal time scales
Authors: Neff William , Perlwitz Judith , Hoerling Martin
Published: September 2008

We use monthly values of geopotential height (GPH) from seven Antarctic stations to examine decadal variations and trends in the overlying troposphere. Whereas the stratospheric signal in our analyses associated with springtime ozone depletion is very detectable, documenting changes in the troposphere is complicated by strong decadal variability and geographical asymmetry. On the Indian‐Ocean coast of Antarctica, negative trends in 500‐hPa GPH prevail from December through May but lower GPH following extreme depletion episodes is only found from December through February. In contrast, the South Pole, McMurdo, and Halley Stations show positive trends for most months and heights with no depletion signal evident in GPH at the South Pole and Halley Stations except at and above 100 hPa. These observed seasonal and geographical asymmetries suggest that the internal dynamical response in the troposphere over Antarctica to climate change and ozone depletion is more complex than is captured in current models.
Reconstruction of a flux transfer event based on observations from five THEMIS satellites
Authors: Lui A. T. Y. , Sibeck D. G. , Phan T. , McFadden J. P. , Angelopoulos V. , Glassmeier K.‐H.
Published: September 2008

We investigate a flux transfer event (FTE) observed by Time History of Events and Macroscale Interactions during Substorms (THEMIS) near the duskside magnetopause using the reconstruction technique based on solving the Grad‐Shafranov equation; see review by Sonnerup et al. (2006). THEMIS D detected the FTE with the largest core magnetic field. THEMIS B and C observed deep troughs in the magnetic field associated with the FTE. THEMIS A and E sensed only slightly altered magnetic field from their surroundings. Two‐dimensional reconstruction maps of magnetic field and plasma pressure are generated by combining observations from all five THEMIS satellites. These reconstructed maps show distinct differences between a magnetic island and an FTE in terms of vector potential and the derived plasma parameters. The origin of the magnetic field troughs in the crater FTEs can be traced to intrusions of the magnetosheath plasma around the structure in the reconstruction maps. Furthermore, the resulting maps show also cylindrical asymmetry in these parameters between the magnetosheath and magnetospheric sides of the FTE. This asymmetry and the different impact parameters of these satellites with respect to the FTE center together contribute to the different characteristics of the FTE signatures seen by the five THEMIS satellites.
Numerical study of mode conversion between lower hybrid and whistler waves on short‐scale density striations
Authors: Eliasson B. , Papadopoulos K.
Published: September 2008

We present a theoretical and numerical study of linear mode conversion of lower hybrid waves interacting with short‐scale density striations in the Earth's ionosphere. The efficiency of the conversion process is investigated for different sets of parameters such as the angle of incidence, the wavelength of the lower hybrid wave, and the size of the striation. It is found that the most efficient whistler generation occurs at a critical angle of incidence where the whistler waves are driven resonantly along the density striations, and when the product of the striation width and the wave number of the lower hybrid wave is of the order unity. It is suggested that whistlers generated as a byproduct of upper hybrid F‐region ionospheric heating can be observed on the ground and by satellites. The generated whistlers could be important for the precipitation of energetic electrons in the radiation belts.
An improved O2 A band absorption model and its consequences for retrievals of photon paths and surface pressures
Authors: Tran H. , Hartmann J.‐M.
Published: September 2008

Deviations from Voigt line profiles in the O2 A band were pointed out in several laboratory and atmospheric studies. In a recent paper, we proposed a model accounting for line mixing and collision‐induced absorption processes for the calculation of absorption by oxygen in this region. The latter was validated by comparison with high‐pressure laboratory spectra, but recent tests using atmospheric measurements evidence inadequacies in that model. We now present some improvements of the approach which are validated by comparisons between predictions and both high‐pressure laboratory absorption spectra and atmospheric spectra. We also study the consequences for retrievals of atmospheric photon path escape factors and pressures from ground‐based Fourier transform solar absorptions. It is shown that this model leads to very satisfactory results, significantly reducing the observed‐fitted spectral residuals and the zenith angle dependence of the photon path escape factor observed previously. It also enables accurate determinations of surface pressure from the inversion of atmospheric spectra.
Remote sensing of mineral dust aerosol using AERI during the UAE2: A modeling and sensitivity study
Authors: Hansell R. A. , Liou K. N. , Ou S. C. , Tsay S. C. , Ji Q. , Reid J. S.
Published: September 2008

Numerical simulations and sensitivity studies have been performed to assess the potential for using brightness temperature spectra from a ground‐based Atmospheric Emitted Radiance Interferometer (AERI) during the United Arab Emirates Unified Aerosol Experiment (UAE2) for detecting/retrieving mineral dust aerosol. A methodology for separating dust from clouds and retrieving the dust IR optical depths was developed by exploiting differences between their spectral absorptive powers in prescribed thermal IR window subbands. Dust microphysical models were constructed using in situ data from the UAE2 and prior field studies while composition was modeled using refractive index data sets for minerals commonly observed around the UAE region including quartz, kaolinite, and calcium carbonate. The T‐matrix, finite difference time domain (FDTD), and Lorenz‐Mie light scattering programs were employed to calculate the single scattering properties for three dust shapes: oblate spheroids, hexagonal plates, and spheres. We used the Code for High‐resolution Accelerated Radiative Transfer with Scattering (CHARTS) radiative transfer program to investigate sensitivity of the modeled AERI spectra to key dust and atmospheric parameters. Sensitivity studies show that characterization of the thermodynamic boundary layer is crucial for accurate AERI dust detection/retrieval. Furthermore, AERI sensitivity to dust optical depth is manifested in the strong subband slope dependence of the window region. Two daytime UAE2 cases were examined to demonstrate the present detection/retrieval technique, and we show that the results compare reasonably well to collocated AERONET Sun photometer/MPLNET micropulse lidar measurements. Finally, sensitivity of the developed methodology to the AERI's estimated MgCdTe detector nonlinearity was evaluated.
Apoptosis as a mechanism of T‐regulatory cell homeostasis and suppression
Authors: Yolcu Esma S , Ash Shifra , Kaminitz Ayelet , Sagiv Yuval , Askenasy Nadir , Yarkoni Shai
Published: September 2008

Activation‐induced cell death is a general mechanism of immune homeostasis through negative regulation of clonal expansion of activated immune cells. This mechanism is involved in the maintenance of self‐ and transplant tolerance through polarization of the immune responses. The Fas/Fas‐ligand interaction is a major common executioner of apoptosis in lymphocytes, with a dual role in regulatory T cell (Treg) function: Treg cell homeostasis and Treg cell‐mediated suppression. Sensitivity to apoptosis and the patterns of Treg‐cell death are of outmost importance in immune homeostasis that affects the equilibrium between cytolytic and suppressor forces in activation and termination of immune activity. Naive innate (naturally occurring) Treg cells present variable sensitivities to apoptosis, related to their turnover rates in tissue under steady state conditions. Following activation, Treg cells are less sensitive to apoptosis than cytotoxic effector subsets. Their susceptibility to apoptosis is influenced by cytokines within the inflammatory environment (primarily interleukin‐2), the mode of antigenic stimulation and the proliferation rates. Here, we attempt to resolve some controversies surrounding the sensitivity of Treg cells to apoptosis under various experimental conditions, to delineate the function of cell death in regulation of immunity.
The decay of magnetohydrodynamic turbulence in a confined domain
Authors: Neffaa Salah , Bos Wouter J. T. , Schneider Kai
Published: September 2008

The effect of nonperiodic boundary conditions on decaying two-dimensional magnetohydrodynamic turbulence is investigated. A circular domain with no-slip boundary conditions for the velocity is considered and where the normal component of the magnetic field vanishes at the wall. Different flow regimes are obtained by starting from random initial velocity and magnetic fields with varying integral quantities. These regimes, equivalent to the ones observed by Ting, Matthaeus, and Montgomery [Phys. Fluids 29, 3261 (1986)] in periodic domains, are found to subsist in confined domains. The effect of solid boundaries on the energy decay and alignment properties is examined. The final states are characterized by functional relationships between velocity and magnetic field.
Recruitment of Eucalyptus strzeleckii (Myrtaceae) in intensive livestock production landscapes
Authors: Moxham Claire , Dorrough Josh
Published: September 2008

Eucalyptus strzeleckii K. Rule (Strzelecki gum) is a medium-to-tall forest swamp gum, endemic to Victoria and listed as Nationally Vulnerable in Australia. This species occurs in the high rainfall (up to 1600 mm) region of Gippsland in south-eastern Victoria. The region has been intensively developed for agriculture, in particular dairy production. Surviving trees are often old and in varying stages of dieback and natural recruitment is rarely observed. The removal of cattle-grazing as a sole mechanism to encourage recruitment is rarely sufficient to promote regeneration of this species. The aim of this study was to examine the role of soil disturbance, weed competition, seed supply and parent plant competition, in the absence of cattle-grazing, in the recruitment of E. strzeleckii. Seed availability, distance from mature tree, soil disturbance, soil moisture and pasture competition all influenced seedling establishment and survival in the field. Removal of ground layer vegetation immediately before seedling emergence appears to be essential for successful establishment of E. strzeleckii. However, both soil disturbance and pasture removal by spraying had similar effects, suggesting that competition rather than soil disturbance per se is a limiting factor in these environments. In the absence of understorey vegetation manipulation, regeneration by this species is unlikely even in the absence of grazing.
Phosphonate alters the defence responses of Lambertia species challenged by Phytophthora cinnamomi
Authors: Suddaby Therese , Alhussaen Khalaf , Daniel Rosalie , Guest David
Published: September 2008

Phytophthora cinnamomi is a destructive pathogen that causes dieback and death in many plant species in Australian native ecosystems. Susceptibility varies widely between related taxa, although the reasons for this variability are poorly understood. In glasshouse studies we confirmed field observations that Lambertia formosa, a New South Wales shrub, is less susceptible to P. cinnamomi than the related Western Australian species, L. inermis. Following inoculation, L. inermis roots are heavily colonised by the pathogen, leading to dieback and high mortality rates. Pathogen restriction in L. formosa correlates with more rapid and intense release of superoxide at the penetration site, and the activation of the phenylpropanoid pathway, than in L. inermis root tissues. Potassium phosphonate reduces symptom severity in inoculated L. formosa, and reduces both mortality and symptom severity in L. inermis. Phosphonate-induced protection in both species is associated with increased superoxide release 8 h after inoculation, and increased phenylalanine ammonia lyase activity 24 h after inoculation.