bluuebunny/crossref_metadata_2025 huggingface dataset:
Age estimates of isochronous reflection horizons by combining ice core, survey, and synthetic radar data
Authors: Eisen Olaf , Nixdorf Uwe , Wilhelms Frank , Miller Heinrich
Published: April 2004

Ice core records and ice‐penetrating radar data contain complementary information on glacial subsurface structure and composition, providing various opportunities for interpreting past and present environmental conditions. To exploit the full range of possible applications, accurate dating of internal radar reflection horizons and knowledge about their constituting features is required. On the basis of three ice core records from Dronning Maud Land, Antarctica, and surface‐based radar profiles connecting the drilling locations, we investigate the accuracies involved in transferring age‐depth relationships obtained from the ice cores to continuous radar reflections. Two methods are used to date five internal reflection horizons: (1) conventional dating is carried out by converting the travel time of the tracked reflection to a single depth, which is then associated with an age at each core location, and (2) forward modeling of electromagnetic wave propagation is based on dielectric profiling of ice cores and performed to identify the depth ranges from which tracked reflections originate, yielding an age range at each drill site. Statistical analysis of all age estimates results in age uncertainties of 5–10 years for conventional dating and an error range of 1–16 years for forward modeling. For our radar operations at 200 and 250 MHz in the upper 100 m of the ice sheet, comprising some 1000–1500 years of deposition history, final age uncertainties are 8 years in favorable cases and 21 years at the limit of feasibility. About one third of the uncertainty is associated with the initial ice core dating; the remaining part is associated with radar data quality and analysis.
In situ validation of Tropical Rainfall Measuring Mission microwave sea surface temperatures
Authors: Gentemann Chelle L. , Wentz Frank J. , Mears Carl A. , Smith Deborah K.
Published: April 2004

We present a validation study of sea surface temperature (SST) retrievals from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). TMI SSTs are calculated using a radiative transfer‐based retrieval algorithm, which precisely accounts for SST and wind effects on surface emissivity as well as atmospheric effects on brightness temperatures. TMI SSTs are compared to 4 years of the National Data Buoy Center, Tropical Atmosphere Ocean/Triangle Trans‐Ocean Buoy Network (TAO/TRITON), and Pilot Research Moored Array in the Tropical Atlantic (PIRATA) moored buoy in situ SSTs. The microwave SSTs are shown to have a mean bias of −0.07°C and a standard deviation of 0.57°C when compared to the TAO/TRITON and PIRATA SSTs. A discussion of time series and dependencies of the accuracy of the TMI SSTs in the presence of varying wind, cloud, and water vapor for each of the buoy arrays is presented. TRMM's precessing equatorial orbit allows the diurnal variability to be determined, revealing midafternoon warming of the surface layer at wind speeds less than 6 m s−1. Low‐wind TAO/TRITON collocations show diurnal warming in both the TMI and buoy retrievals, with TMI's diurnal peak larger and 1 hour before the buoy peak. This decoupling of the skin‐bulk SSTs results in larger standard deviations for daytime low‐wind situations. This result has direct implications for future in situ validation studies, in situ‐based regression algorithms, and future blended infrared/microwave/in situ SST products.
Modeling the tropical climate and the impact of the western Pacific sea surface temperature at the Last Glacial Maximum
Authors: Zhao Ping , Zhou Xiuji , Jian Zhimin , Sparrow Michael , Han Yu
Published: April 2004

Changes in tropical atmospheric heat and circulation patterns, as well as the effects of sea surface temperature (SST) of the western Pacific during the Last Glacial Maximum (LGM), have been investigated using a climate model and the LGM SST compiled by Wang [1999]. The annual mean LGM SST was 2°–4°C lower than the present day in the tropical western Pacific west of 140°E. Simulations show that the largest decrease of atmospheric heat occurs in the tropics in a region stretching from the Bay of Bengal to the central Pacific Ocean, while there are no significant changes in atmospheric heat at higher latitudes. This indicates that the atmospheric heat in the tropics shows a stronger response to boundary changes between the LGM and the present day than it does at higher latitudes, since the tropical convection amplifies the response of the atmosphere in the former case. Because of this tropical heat change, the Walker circulation, the transverse monsoon, and the east Asian summer monsoon at the LGM were weaker than they are at present. The model with the Wang [1999] LGM SST simulated large changes in atmospheric circulation in the tropics and high northern latitudes compared to the Climate, Long‐Range Investigation, Mapping and Prediction (CLIMAP) [CLIMAP Project Members, 1981] project's reconstruction. The Wang [1999] LGM SST was also associated with a lower surface air temperature (SAT) at high northern latitudes and the Arctic and with a cooler temperature of the coldest month in Europe. The annual mean SAT decreased by 2°C in the Arctic, and the winter mean SAT decreased by 4°C in Europe.
Vertical control point network and global shape of Io
Authors: Oberst Jürgen , Schuster Peter
Published: April 2004

We have analyzed Galileo and Voyager images of Io to derive global control point networks, involving 402 (Galileo) and 158 (Voyager) surface points as well as combinations of the two data sets. Using block adjustment techniques, three‐dimensional coordinates of the control points are derived with an accuracy of 4.7 km (Galileo) and 8.6 km (Voyager). Three‐axial ellipsoids are fitted to the Galileo control points, for which we find the following: a = 1831.1 ± 0.3 km, b = 1820.4 ± 0.4 km, and c = 1816.6 ± 0.5 km. Our results on size and shape confirm that Io (in synchronous rotation and exposed to strong tidal and rotational forces) is in hydrostatic equilibrium and has a pronounced mass concentration toward the center, in agreement with suggested Fe‐ and Fe/S cores of 740 and 1000 km radius, respectively. However, our shape model is unable to resolve long‐wavelength topography beyond the ellipsoidal parameters. Studies of synthetic Galileo and Voyager control point data sets are carried out to track error propagation in our control point networks and to compare the geometric performance of the two spacecraft cameras. We find that Voyager Vidicon images suffer from residual geometric errors on the order of 1/3 of a pixel, which adds to the typical image coordinate measurement errors (slightly less than 1/2 pixel) that apply for Galileo or Voyager images alike. We therefore suggest that previous authors have overestimated the accuracy of their Voyager‐based control point networks and global topographic maps significantly.
Surface winds, divergence, and vorticity in stratocumulus regions using QuikSCAT and reanalysis winds
Authors: McNoldy B. D. , Ciesielski P. E. , Schubert W. H. , Johnson R. H.
Published: April 2004

High spatial resolution QuikSCAT data are used to examine surface winds, divergence, and vorticity over oceanic regions during the boreal summer. These analyses are compared to those from earlier observational studies, as well as ECMWF and NCEP reanalysis products. QuikSCAT analyses generally confirm the results from early studies and the reanalyses, but add important details to our view of the surface circulation in Atlantic and East Pacific regions.
Strategy‐as‐practice: reflections on the research agenda
Authors: Chia Robert
Published: April 2004

Abstract Strategy‐as‐practice has become an important alternative to the hitherto dominant institutional and resource‐based approaches to strategy research. This paper examines some of the underlying conceptions of ‘practice’ and its implications for researching the micro‐practices of strategizing. It concludes with the observation that the notion of habitus is a better way of understanding how consistency and hence strategy in action is achieved and how we might begin to understand strategy‐as‐practice in terms of a certain style of engagement.
The Ysterfontein 1 Middle Stone Age site, South Africa, and early human exploitation of coastal resources
Authors: Klein Richard G. , Avery Graham , Cruz-Uribe Kathryn , Halkett David , Parkington John E. , Steele Teresa , Volman Thomas P. , Yates Royden
Published: April 2004

Human fossils and the genetics of extant human populations indicate that living people derive primarily from an African population that lived within the last 200,000 years. Yet it was only ≈50,000 years ago that the descendants of this population spread to Eurasia, where they swamped or replaced the Neanderthals and other nonmodern Eurasians. Based on archaeological observations, the most plausible hypothesis for the delay is that Africans and Eurasians were behaviorally similar until 50,000 years ago, and it was only at this time that Africans developed a behavioral advantage. The archaeological findings come primarily from South Africa, where they suggest that the advantage involved much more effective use of coastal resources. Until now, the evidence has come mostly from deeply stratified caves on the south (Indian Ocean) coast. Here, we summarize results from recent excavations at Ysterfontein 1, a deeply stratified shelter in a contrasting environment on the west (Atlantic) coast. The Ysterfontein 1 samples of human food debris must be enlarged for a full comparison to samples from other relevant sites, but they already corroborate two inferences drawn from south coast sites: (i) coastal foragers before 50,000 years ago did not fish routinely, probably for lack of appropriate technology, and (ii) they collected tortoises and shellfish less intensively than later people, probably because their populations were smaller.
Errα and Gabpa/b specify PGC-1α-dependent oxidative phosphorylation gene expression that is altered in diabetic muscle
Authors: Mootha Vamsi K. , Handschin Christoph , Arlow Dan , Xie Xiaohui , St. Pierre Julie , Sihag Smita , Yang Wenli , Altshuler David , Puigserver Pere , Patterson Nick , Willy Patricia J. , Schulman Ira G. , Heyman Richard A. , Lander Eric S. , Spiegelman Bruce M.
Published: April 2004

Recent studies have shown that genes involved in oxidative phosphorylation (OXPHOS) exhibit reduced expression in skeletal muscle of diabetic and prediabetic humans. Moreover, these changes may be mediated by the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α). By combining PGC-1α-induced genome-wide transcriptional profiles with a computational strategy to detect cis-regulatory motifs, we identified estrogen-related receptor α (Errα) and GA repeat-binding protein α as key transcription factors regulating the OXPHOS pathway. Interestingly, the genes encoding these two transcription factors are themselves PGC-1α-inducible and contain variants of both motifs near their promoters. Cellular assays confirmed that Errα and GA-binding protein a partner with PGC-1α in muscle to form a double-positive-feedback loop that drives the expression of many OXPHOS genes. By using a synthetic inhibitor of Errα, we demonstrated its key role in PGC-1α-mediated effects on gene regulation and cellular respiration. These results illustrate the dissection of gene regulatory networks in a complex mammalian system, elucidate the mechanism of PGC-1α action in the OXPHOS pathway, and suggest that Errα agonists may ameliorate insulin-resistance in individuals with type 2 diabetes mellitus.
Bourdieu's Habitus, Social Class and the Spatial Worlds of Visually Impaired Children
Authors: Allen Chris
Published: April 2004

This paper argues that the 'new' social geographies of impairment literature present a sophisticated analysis of the socio-spatiality of the impaired body, but one that now needs developing in two ways. First, it is suggested that the literature has focused on the embodiment of socio-spatial exclusion more than it has focused on resistance to it. Secondly, where the literature has analysed resistance to socio-spatial exclusion, it has done so in general terms (i.e. by referring to 'disabled people'). The literature has said less about whether and how factors such as social class background might predispose some impaired people (but not others) to resist their embodiment of disability and socio-spatial exclusion and less about the way in which impaired people develop ways of navigating the 'off limits' urban spaces that they now wish to use. The paper uses the work of Pierre Bourdieu to construct a theoretical framework within which some empirical data, concerning these underresearched issues, are analysed.
Residential Assistance and Recovery Following the Northridge Earthquake
Authors: Kamel Nabil M. O. , Loukaitou-Sideris Anastasia
Published: April 2004

This paper examines the implementation of post-disaster US federal assistance programmes for residential reconstruction and investigates the relationship between socio-demographic characteristics of places and access to residential assistance following the Northridge earthquake that hit Los Angeles in 1994. The paper also examines the effects of the distribution of assistance on long-term recovery outcomes. Findings suggest that areas with high levels of socially marginalised populations were at a disadvantage in accessing federal residential assistance. Findings also show that the long-term effects of the earthquake differed depending on levels of assistance relative to damage. Areas that received less assistance experienced losses in population and housing units. These findings indicate that post-disaster recovery programmes in the US do not adequately address the wide range of housing needs that emerge in the case of a major disaster in a large metropolitan area. Implications for post-disaster planning as well as for planning under everyday conditions are discussed.
User Cost Changes, Unemployment and Home-ownership: Evidence from Spain
Authors: Barrios Garcia Javier A. , Rodriguez Hernandez Jose E.
Published: April 2004

This paper develops a macroeconomic model that permits analysis of the relationship between unemployment and home-ownership rates using aggregate data at the provincial level within Spain, besides other influential variables such as the changes of the relative user costs of owning and renting or household life-cycle attributes. The model constructed permits the authors to question the evidence of Oswald, Nickell and Layard, and partially of Green and Hendershott, that home-ownership leads to higher unemployment. The results point out that, taking into account the simultaneity determination issue and reducing the omitted variable bias, a higher unemployment discourages home-ownership.
From Valley of Sadness to Hill of Happiness: The Significance of Surroundings for Socioeconomic Career
Authors: Andersson Eva
Published: April 2004

Interest in neighbourhood effects has been increasing. This article is a contribution to the field, directed towards the entire areas of three municipalities in Sweden, not only their distressed areas, and to their total population with data from the Statistics Sweden register. The aim of the study is to analyse the significance of surroundings to an individual's socioeconomic career in the form of education, occupational status and income. Guided by a theoretical framework of social justice, the study proposes places of good fortune and places of few opportunities. The survey cohort is individuals born in 1970, who lived at least 5 years in the same area during their adolescence. Their careers are analysed 10 years later, in 1995. The most important finding is that the socio-demographic and physical context of the residential area of adolescence affects the subsequent socioeconomic career.
Substance‐Abusing Schizophrenics: Do They Self‐Medicate?
Authors: Goswami Santanu , Mattoo Surendra K. , Basu Debasish , Singh Gagandeep
Published: April 2004

In spite of having been formulated nearly two decades back, there is as yet no consensus on the validity of the clinically popular self‐medication hypothesis (SMH) of substance use disorders in patients with dual diagnosis. SMH broadly proposes that patients use substances in a non‐random fashion so that the psychopharmacologic characteristics of particular substances are used to alleviate a variety of psychiatric symptoms and emotional distress. In order to test the SMH empirically, it was broken down to five sub‐hypotheses, which were tested in a group of dual‐diagnosis schizophrenia (DDS) patients vis‐a‐vis a group of only‐schizpphrenia (S) patients (n = 22 each). The DDS group scored lower than the S group regarding general and some specific psychopathology. The DDS patients ascribed reasons for substance use more often for hedonistic pursuit but also for reduction in symptoms and distress. There was a trend for alcohol to be used more for self‐medication purposes compared to opioids and cannabis. The perceived effects of these three substances were significantly different on several symptom / distress dimensions. Finally, there was some degree of “match” between symptom‐oriented reasons for use of substances and the effect that was perceived. All of this evidence provides a consistent but modest support for the SMH for “some patients, some substances, and some symptoms.” The implications are discussed. (Am J Addict 2004;13:139–150)
Genetic study of alcoholism and novel gene expression in the alcoholic brain
Authors: Fan Li , Bellinger Frederick , Ge Yong‐Liang , Wilce Peter
Published: April 2004

Alcohol dependence may result from neuroadaptation involving alteration of gene expression after long‐term alcohol exposure. The systematic study of gene expression profiles of the human alcoholic brain was initiated using the method of polymerase chain reaction (PCR)‐differential display and was followed by DNA microarray. To date, more than 100 alcohol‐responsive genes have been identified from the frontal cortex, motor cortex and nucleus accumbens of the human brain. These genes have a wide range of functions in the brain and indicate diverse actions of alcohol on neuronal function. This review discusses the current information on the genetic basis of alcoholism and the induction and characterization of these alcohol‐responsive genes.
Functional changes in dopamine D3 receptors by prenatal and neonatal exposure to an endocrine disruptor bisphenol‐A in mice
Authors: Mizuo Keisuke , Narita Minoru , Yoshida Takuya , Narita Michiko , Suzuki Tsutomu
Published: April 2004

Bisphenol‐A (BPA), one of the most common environmental endocrine disrupters, has been evaluated extensively for toxicity and carcinogenicity. However, little is still known about its action on the central nervous system (CNS). In the previous study, we found that prenatal and neonatal exposure to BPA markedly enhanced the rewarding effect induced by morphine. Here we found that prenatal and neonatal exposure to BPA resulted in the attenuation of dopamine D3 receptor‐mediated G‐protein activation by 7‐OH‐DPAT in the mouse limbic forebrain. This treatment also caused a significant decrease in the B max value of [3H]PD128907, a dopamine D3 receptor ligand, in this area. Under these conditions, no change in dopamine D3 receptor mRNA expression in the limbic forebrain and lower midbrain was observed by prenatal and neonatal exposure to BPA. The present data provide further evidence that prenatal and neonatal exposure to BPA leads to the reduction of functional dopamine D3 receptors without affecting the new synthesis of dopamine D3 receptors in the mouse limbic forebrain.
Wigner-Yanase skew information vs. quantum Fisher information
Authors: Luo Shunlong
Published: April 2004

Among concepts describing the information contents of quantum mechanical density operators, both the Wigner-Yanase skew information and the quantum Fisher information defined via symmetric logarithmic derivatives are natural generalizations of the classical Fisher information. We will establish a relationship between these two fundamental quantities and show that they are comparable.
Σ_{𝑛}-bounding and Δ_{𝑛}-induction
Authors: Slaman Theodore
Published: April 2004

Working in the base theory ofPA−+IΣ0+exp\mathrm {PA}^- + \mathrm {I}\Sigma _0 +\exp, we show that for alln∈ωn\in \omega, the bounding principle forΣn\Sigma _n-formulas (BΣn\mathrm {B}\Sigma _n) is equivalent to the induction principle forΔn\Delta _n-formulas (IΔn\mathrm {I}\Delta _n). This partially answers a question of J. Paris.
Uniqueness of travelling waves for nonlocal monostable equations
Authors: Carr Jack , Chmaj Adam
Published: April 2004

We consider a nonlocal analogue of the Fisher-KPP equation
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="u Subscript t Baseline equals upper J asterisk u minus u plus f left-parenthesis u right-parenthesis comma x element-of upper R comma f left-parenthesis 0 right-parenthesis equals f left-parenthesis 1 right-parenthesis equals 0 comma f greater-than 0 on left-parenthesis 0 comma 1 right-parenthesis comma">

u
t

=
J
∗
u
−
u
+
f
(
u
)
,
 
x
∈
R
,
 
f
(
0
)
=
f
(
1
)
=
0
,
 
f
>
0
 

on

 
(
0
,
1
)
,

u_t =J*u-u+f(u),~x\in R,~f(0)=f(1)=0,~f>0 ~\textrm {on}~(0,1),

\]
and its discrete counterpart

u
˙

n

=
(
J
∗
u

)
n

−

u
n

+
f
(

u
n

)

{\dot u}_n =(J*u)_n -u_n +f(u_n )

,

n
∈
Z

n\in Z

, and show that travelling wave solutions of these equations that are bounded between

0
0

and

1
1

are unique up to translation. Our proof requires finding exact a priori asymptotics of a travelling wave. This we accomplish with the help of Ikehara’s Theorem (which is a Tauberian theorem for Laplace transforms).
Effect of aggregation on population recovery modeled by a forward-backward pseudoparabolic equation
Authors: Padrón Víctor
Published: April 2004

In this paper we study the equation
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="u Subscript t Baseline equals normal upper Delta left-parenthesis phi left-parenthesis u right-parenthesis minus lamda f left-parenthesis u right-parenthesis plus lamda u Subscript t Baseline right-parenthesis plus f left-parenthesis u right-parenthesis">

u
t

=
Δ
(
ϕ
(
u
)
−
λ
f
(
u
)
+
λ

u
t

)
+
f
(
u
)

u_t=\Delta (\phi (u) - \lambda f(u) + \lambda u_t) + f(u)

\]
in a bounded domain of

R

d

\mathbb {R}^d

,

d
≥
1

d\ge 1

, with homogeneous boundary conditions of the Neumann type, as a model of aggregating population with a migration rate determined by

ϕ
\phi

, and total birth and mortality rates characterized by

f
f

. We will show that the aggregating mechanism induced by

ϕ
(
u
)

\phi (u)

allows the survival of a species in danger of extinction. Numerical simulations suggest that the solutions stabilize asymptotically in time to a not necessarily homogeneous stationary solution. This is shown to be the case for a particular version of the function

ϕ
(
u
)

\phi (u)

.
Recent advances in the Langlands Program
Authors: Frenkel Edward
Published: April 2004

These are the notes for the lecture given by the author at the “Mathematical Current Events" Special Session of the AMS meeting in Baltimore on January 17, 2003. Topics reviewed include the Langlands correspondence for

G
L
(
n
)

GL(n)

in the function field case and its proof by V. Drinfeld and L. Lafforgue; the geometric Langlands correspondence for

G
L
(
n
)

GL(n)

and its proof by D. Gaitsgory, K. Vilonen and the author; and the work of A. Beilinson and V. Drinfeld on the quantization of the Hitchin system and the Langlands correspondence for an arbitrary semisimple algebraic group.
Spinning deformations of rational maps
Authors: Pilgrim Kevin , Lei Tan
Published: April 2004

We analyze a real one-parameter family of quasiconformal deformations of a hyperbolic rational map known as spinning. We show that under fairly general hypotheses, the limit of spinning either exists and is unique, or else converges to infinity in the moduli space of rational maps of a fixed degree. When the limit exists, it has either a parabolic fixed point, or a pre-periodic critical point in the Julia set, depending on the combinatorics of the data defining the deformation. The proofs are soft and rely on two ingredients: the construction of a Riemann surface containing the closure of the family, and an analysis of the geometric limits of some simple dynamical systems. An interpretation in terms of Teichmüller theory is presented as well.
The oxymoron of control in an era of globalisation
Authors: Bijlsma‐Frankema Katinka , Koopman Paul
Published: April 2004

In response to developments around as well as within organisations, managers are faced with a control‐commitment dilemma. A new rationality of governance has emerged besides the well‐known rationality of bureaucratic control. This new set of governance strategies, which is presented under different labels such as commitment‐based management or trust‐based governance, is directed at access to and leverage of intangible resources like employee commitment, tacit knowledge and learning behaviours. In this special issue, six studies are presented that address the subject of how top management teams deal with this control‐commitment dilemma and the intended or unintended consequences of choices made.
Dilemmas of managerial control in post‐acquisition processes
Authors: Bijlsma‐Frankema Katinka
Published: April 2004

In this study, nine managers of a Dutch multinational engineering company were interviewed on the success and failure factors of post‐acquisition processes they were involved in over the past five years. When referring to their experiences, the managers mainly spoke about failures and how to avoid these in future. The focus of this study was on the cognitive map structure of the perspectives of managers as disclosed by the interview data. Three different collective maps were found, representing “the Strategists”, strategic business unit‐presidents, and human resource (HR)‐managers. The maps show differences in perspectives on four central themes: control versus cooperation; how to handle the culture of the acquired firm; trust versus distrust; and speed versus carefulness. If the maps are compared with literature on management acquisition processes, the HR‐managers' map shows richer insights into how to manage human factors in acquisition processes than the other two. Instead of exploiting these valuable insights, the differences in perspectives fostered distrust between the two management levels, which constrained mutual learning.
Implicit communication in organisations
Authors: Hoogervorst Jan , van der Flier Henk , Koopman Paul
Published: April 2004

Organisations engage in explicit and intentional communication with employees in various ways. However, communication will not be received in a “neutral” context. Employees operate in an organisational (or behavioural) context determined by the organisational culture, structures and systems, and the management practices. This context acts as a source of implicit communication towards employees. This view fits the various perspectives about communication, which does not need to be considered as a two‐way process, and which can be intentionally or unintentionally, transmitted and received. All too often, implicit communication is at odds with the “official” explicit communication. Through this latter form of communication the organisation might, for example, proclaim a quality image, while in reality employees experience that, in case of conflicts, delivery planning prevails over quality. Likewise, communication about the “learning organisation” appears to be cumbersome in a culture suppressing discussion about failures. The effect of implicit communication should not be underestimated. Cynicism among employees is repeatedly the result of inconsistent messages being received. This paper describes the aspects of organisational culture, structures and systems, and management practices, seen in a behavioural context, in order to illustrate how these aspects act as an implicit source of communication to employees. Additionally, this form of communication expresses whether employees themselves are seen as the crucial core of organisational success. The importance of consistent signals is illustrated, specifically with respect to organisational change programs.
Librarians in the knowledge age
Authors: Materska Katarzyna
Published: April 2004

The knowledge age has created a new context and challenges for different organisations and professional groups. Understanding the forces and trends that are shaping the future of the knowledge territory is very important for librarians. The knowledge economy exists in a multi‐networked environment. Under the “network economy” the network of relationships is more important than the ownership of assets. This paper concentrates on how librarians become knowledge workers and support other knowledge workers' communities. The new roles and skills (particularly communication and interpersonal skills which play a great role in preparing new information products) are presented as a basis for the discussion.
Olprinone improves diaphragmatic contractility and fatigability during abdominal sepsis in a rat model
Authors: Miyakawa H. , Oishi K. , Hagiwara S. , Kira S. , Kitano T. , Iwasaka H. , Noguchi T.
Published: April 2004

Background:  Respiratory failure with diaphragmatic fatigability is common in patients suffering sepsis or septic shock. However, the development and progress of diaphragmatic fatigability remains poorly understood, and no method has been established to treat fatigability. In this study, we hypothesize that neutrophil activation contributes to the development of diaphragmatic fatigability. We also sought to investigate whether a phosphodiesterase inhibitor, olprinone, improves diaphragmatic fatigability associated with abdominal sepsis and inhibits an increase in myeloperoxidase activity in diaphragmatic muscle.

Methods:  Male Wistar rats were randomly assigned to a sham group, coecal legation perforation group (CLP), and a phosphodiesterase inhibitor (PDE) pretreated group. At 16 h after surgical procedure, the left hemidiaphragm was removed for the measurement of diaphragmatic contractility and fatigability. In addition, for the measurement of serial changes in myeloperoxidase activity, the right hemidiaphragm was also removed at 4, 8 or 16 h after the surgical procedure in each group.

Results:  In a septic model involving rats, we observed that diaphragmatic muscles were fatigable and myeloperoxidase activity increased. We also demonstrated that intraperitoneal administration of olprinone improves diaphragmatic fatigability and inhibits an increase in myeloperoxidase activity induced by abdominal sepsis.

Conclusion:  Olprinone represents a potential therapy for cases of respiratory failure with diaphragmatic fatigability resulting from inhibition of neutrophil activation.
High‐dose bupivacaine, levobupivacaine and ropivacaine in axillary brachial plexus block
Authors: Liisanantti O. , Luukkonen J. , Rosenberg P. H.
Published: April 2004

Background:  Racemic bupivacaine is clinically similar to levobupivacaine, or ropivacaine. The drugs were compared in brachial plexus block for the first time in the same randomized and double‐blind study.

Methods:  In 90 patients scheduled for hand and forearm surgery, a perivascular axillary brachial plexus block was performed with 45 ml of 5 mg ml−1 of either racemic bupivacaine‐HCl, levobupivacaine‐HCl, or ropivacaine‐HCl. Sensory (cold) and motor (hand clasp, and movement of elbow) block were scored, and the patient was interviewed in the postoperative evening and the following morning. Time to normal function of the arm was registered.

Results:  After similar onsets of sensory block, the sum of completely anaesthetized innervation areas of the four main nerves at 45 min was greater in the ropivacaine group than in the levobupivacaine group (P < 0.01). Simultaneously, complete motor block at the elbow was more frequent in the ropivacaine group (67%) than in the bupivacaine (47%) and levobupivacaine groups (30%) (P < 0.01). In the hand, the corresponding results were 83%, 77%, and 57%, respectively (NS). Two patients in the levobupivacaine and one in the ropivacaine group needed general anaesthesia. Mean duration of the blocks was similar in the bupivacaine, levobupivacaine and ropivacaine groups at 19.3 h, 19.5 h, and 17.3 h, respectively (NS). Two patients were dissatisfied with the long block duration.

Conclusion:  Ropivacaine‐HCl 5 mg ml−1 produced slightly better sensory and motor block intensity than the same dose of levobupivacaine‐HCl. General success in relation to surgery and in the duration of the blocks was similar in the three groups.
The Polls: Partisanship and Presidential Performance Evaluations
Authors: BOND JON R. , FLEISHER RICHARD
Published: April 2004

This article analyzes the growing impact of partisanship on citizens' evaluations of the president's job performance at the individual level. The literature seeking to explain variation in presidential approval has analyzed aggregate trends over time. Although studies of aggregate trends have contributed to our understanding of the conditions that influence presidential approval, they are unable to model the individual‐level process underlying the aggregate results. The authors estimate the effects of individual citizens' party identification and retrospective and prospective economic evaluations on presidential approval in thirteen national samples over the two and one‐half decades from 1972 to 2000. It is found that party identification has a stronger influence on evaluations of the president's job performance in the period since 1982 than in the 1970s. Evidence is also found of an increasing tendency for partisanship to influence assessments of the economy in the period since 1982.
Counterfactuals and the Study of the American Presidency
Authors: Chwieroth Jeffrey M.
Published: April 2004

King (1993) argues that with the small number of presidents available for study, presidency scholars cannot construct reliable causal inferences by employing the presidency as the unit of observation. He goes on to suggest that presidency scholars should abandon such research designs and search for ways to increase their number of observations. This article evaluates King's methodological prescription by examining the utility of counterfactuals for presidency scholars. Relying on recent scholarship on counterfactuals, the author argues that presidency scholars may be able to produce reliable causal inferences while continuing to rely on the presidency as the unit of observation. He goes on to specify the conditions under which counterfactuals may be useful and illustrate the application of this method by examining Woodrow Wilson's failed effort to secure ratification of the Versailles Treaty. The author concludes that if presidency scholars' research dictates relying on the president as the unit of observation, then they are left with little choice but to rely on this method to test their theories with an adequate degree of certainty.
Effect of gamma‐hydroxybutyric acid on tissue Na+,K+‐ATPase levels after experimental head trauma
Authors: Yosunkaya A. , Üstün M. E. , Bariskaner H. , Tavlan A. , Gürbilek M.
Published: April 2004

Background:  A failure of the Na+,K+‐ATPase activity (which is essential for ion flux across the cell membranes) occurs in many pathological conditions and may lead to cell dysfunction or even cell death. By altering the concentration of specific opioid peptides, gamma‐hydroxybutyric acid (GHB) may change ion flux across cell membranes and produce the ‘channel arrest’ which we assumed will inhibit the failure of Na+,K+‐ATPase activity and therefore lead to energy conservation and cell protection. Therefore we planned this study to see the effects of GHB at two different doses on Na+,K+‐ATPase activity in an experimental head trauma model.

Methods:  Forty New Zealand rabbits were divided equally into four groups: group I was the sham‐operated group, group II (untreated group), group III received head trauma and intravenous (i.v.) 500 mg/kg GHB and group IV received head trauma and i.v. 50 mg/kg GHB. Head trauma was delivered by performing a craniectomy over the right hemisphere and dropping a weight of 10 g from a height of 80 cm. The non‐traumatized (left) side was named as ‘a’ and the traumatized (right) side as ‘b’. One hour after the trauma in groups II and III and craniotomy in group I, brain cortices were resected from both sides and in group I only from the right side was the tissue Na‐K‐ATPase activity determined.

Results:  The mean ± SD of Na+,K+‐ATPase levels of each group are as follows: group I – 5.97 ± 0.55; group IIa – 3.90 ± 1.08; group IIb – 3.58 ± 0.90; group IIIa – 5.53 ± 0.60; group IIIb – 5.33 ± 0.88; group IVa – 5.05 ± 0.72; group IVb – 4.93 ± 0.67. The Na+,K+‐ATPase levels of group IIa, IIb, IVa and IVb were significantly different from group S (P < 0.05). There were also significant differences between group IIa and groups IIIa and IVa; group IIb and groups IIIb and IVb (P < 0.05).

Conclusions:  We conclude that GHB is effective in suppressing the decrease in Na+,K+‐ATPase levels in brain tissue at two different dose schedules after head trauma.
The analgesic effect of morphine on postoperative pain in diabetic patients
Authors: Karci A. , Tasdogen A. , Erkin Y. , Aktaş G. , Elar Z.
Published: April 2004

Background:  Many clinical and experimental studies have suggested that diabetes or hyperglycemia alter opioid responsiveness. However, little information is available on the effects of diabetes mellitus on opioid requirements in the postoperative period.

Methods:  Sixty‐four patients scheduled for elective, total abdominal hysterectomy were included into this prospective study to evaluate the effect of diabetes mellitus on morphine requirement in the postoperative period. A loading dose of morphine (50 µg kg−1) was administered in the perioperative period. Postoperative analgesia consisted of intravenous morphine‐PCA. No analgesic other than morphine was allowed during the study. In cases of inadequate analgesia intravenous 1 mg of morphine was given as a rescue analgesic. Cumulative morphine consumption, pain scores and morphine‐related adverse effects were recorded.

Results:  A total of 60 patients were evaluated: Group D, 30; and Group ND, 30. Patients in Group D received more morphine than those in Group ND (54.12 ± 25.09 and 42.66 ± 20.67, respectively). The difference in cumulative morphine consumption was higher in the first hour (P = 0.037) in diabetic patients and they required significantly more morphine in the last 24 h (P = 0.015). Postoperative pain scores were higher in the diabetic group. More patients in the diabetic group required rescue medication (26 vs. 19) and felt nauseous (25 vs. 14; P = 0.003).

Conclusion:  The findings of the study appear to support experimental and clinical impressions that the analgesic effect of morphine is attenuated in hyperglycemic conditions. Therefore, larger doses of morphine may be administered to diabetic patients for effective postoperative analgesia.
Avian Risk Assessment: Effects of Perching Height and Detectability
Authors: Blumstein Daniel T. , Fernández‐Juricic Esteban , LeDee Olivia , Larsen Elisabeth , Rodriguez‐Prieto Iñaki , Zugmeyer Claire
Published: April 2004

We studied two components of predator risk assessment in birds. While many species are limited to seeking safety under cover or under ground, some birds can fly away from their predators and escape to trees. If birds in fact ‘feel’ safer (e.g. perceive less risk) in trees, we would expect them to tolerate closer approach by a potential terrestrial predator. Another component of safety is at which point the animal detects an approaching threat, which we expected to increase with eye size, assuming eye size is a surrogate for visual acuity. We used the distance birds moved away from an approaching human [flight initiation distance (FID)] as a metric to determine whether birds associated a lower risk of predation by being in trees, and we used the distance at which birds first displayed alert behaviors from an approaching human (alert distance) to determine if birds with larger eyes had higher detection distances. Although some species were affected by tree height, we found no clear pattern that birds assessed themselves to be at a lower risk of predation when they were ≥3 m above the ground compared with being <3 m above ground. In the 10 species for which height had any significant effect on FID, birds ≥3 m off the ground had greater FIDs in six species, but the remaining three species had the opposite response. While we found a significant positive relationship between eye size and alert distance in 23 species, the relationship was not present in a phylogenetic analysis using independent contrasts, which suggests that the apparent relationship was influenced strongly by the association between the studied species. Together, these results suggest that birds do not obviously associate being in a tree with safety, and that variations in visual acuity, per se, cannot be used as a general indicator of differences in alert distances, as previously suggested in the literature.
The Influence of Predator Sex on Chemically Mediated Antipredator Response in the Wolf SpiderPardosa milvina(Araneae: Lycosidae)
Authors: Lehmann Leilani M. , Walker Sean E. , Persons Matthew H.
Published: April 2004

The wolf spider,Pardosa milvina, reduces activity in the presence of chemical cues (silk and excreta) from a larger predatory wolf spider,Hogna helluo.Hognais sexually dimorphic in body size and males and females differ in their propensity to attack prey. Consequently, each sex may present different levels of risk toPardosa. We measured predation risk ofPardosain the presence of male or femaleHogna. We also assessedPardosaantipredator responses and survival in the presence or absence of previously deposited chemical cues from male or femaleHogna. In the absence of predator chemical cues,Pardosasurvived significantly longer in the presence of maleHognacompared with femaleHogna. We then assessedPardosasurvival in the presence of chemical cues from eachHognasex by placingPardosain containers previously occupied by a femaleHogna, a maleHogna, or noHogna(control). We then introduced a femaleHognainto each container and measured predation latency.Pardosasurvived significantly longer in the presence of female and male cues compared with the control treatment. Median survival time ofPardosawas over four times longer on substrates with femaleHognacues compared with male cues, but this difference was not statistically significant. We testedPardosaactivity levels in the presence of chemical cues from male or femaleHogna. BothHognasexes were maintained in separate containers after which we placed an adult femalePardosain one of the containers or a blank control container.Pardosasignificantly decreased activity in the presence of chemical cues from either sex relative to the control. Activity was lowest on substrates with femaleHognacues, but not significantly lower than on substrates with maleHognacues. Results suggest that chemical information from male or femaleHognasignificantly reducesPardosaactivity which results in increased survival.
The clinical home community: a model for community‐based education
Authors: Williams‐Barnard C. L. , Sweatt A. H. , Harkness G. A. , DiNapoli P.
Published: April 2004

Background:  Escalating health care costs, racial inequities and socioeconomic disparities have limited access for many to even the barest of health care services. The paradigm shift to a health promotion, disease prevention, and health restoration model within a community‐based framework demands greater integrated learning experiences for nursing students that are centred where clients live, work, and play.

Aim:  To describe the process of developing, implementing and evaluating a rural New England University's experience of piloting a clinical home community model within its existing baccalaureate curriculum.

Content:  The model describes how it is possible to break free from traditional acute care settings in hospitals and mental health institutions. Students are provided with maternal‐child and adult mental health experiences that are available in a targeted clinical home community setting where consumers are increasingly seeking health care. The concepts that directed curriculum revision from a traditional to a community‐based educational framework are discussed.

Outcomes:  Strengths and limitations of the model are presented within the context of student, faculty and consumer partnerships. Implications for global development of the clinical home community model in nursing are proposed.
Evolution and development of brain sensory organs in molgulid ascidians
Authors: Jeffery William R.
Published: April 2004

Summary The ascidian tadpole larva has two brain sensory organs containing melanocytes: the otolith, a gravity receptor, and the ocellus, part of a photoreceptor. One or both of these sensory organs are absent in molgulid ascidians. We show here that developmental changes leading to the loss of sensory pigment cells occur by different mechanisms in closely related molgulid species. Sensory pigment cells are formed through a bilateral determination pathway in which two or more precursor cells are specified as an equivalence group on each side of the embryo. The precursor cells subsequently converge at the midline after neurulation and undergo cell interactions that decide the fates of the otolith and ocellus. Molgula occidentalis and M. oculata, which exhibit a tadpole larva with an otolith but lacking an ocellus, have conserved the bilateral pigment cell determination pathway. Programmed cell death (PCD) is superimposed on this pathway late in development to eliminate the ocellus precursor and supernumerary pigment cells, which do not differentiate into either an otolith or ocellus. In contrast to molgulids with tadpole larvae, no pigment cell precursors are specified on either side of the M. occulta embryo, which forms a tailless (anural) larva lacking both sensory organs, suggesting that the bilateral pigment cell determination pathway has been lost. The bilateral pigment cell determination pathway and superimposed PCD can be restored in hybrids obtained by fertilizing M. occulta eggs with M. oculata sperm, indicating control by a zygotic process. We conclude that PCD plays an important role in the evolution and development of brain sensory organs in molgulid ascidians.