bluuebunny/crossref_metadata_2025 huggingface dataset:
Dilemma of Non‐Steady State in Lakes – Development and Predictability of In‐Lake P Concentration in Dimictic Lake Scharmützelsee (Germany) after Abrupt Load Reduction
Authors: Grüneberg Björn , Rücker Jacqueline , Nixdorf Brigitte , Behrendt Horst
Published: November 2011

Based on measured and calculated long‐term data on external phosphorus (P) load (1920–2009), hypolimnetic P accumulation and trophic parameters for the dimictic Lake Scharmützelsee, we aimed to identify factors which cause variable P net sedimentation and the importance of internal P loading for different time periods especially focusing on non‐steady state after abrupt external load reduction in 1988. P retention (R) decreased from 0.85 during the high external P loading (0.37 g m–2 a–1) phase (1950–1988) to 0.71 during the following transient phase, and increased to 0.81 for the present recovery phase (0.17 g m–2 a–1) beginning in 2003. Mean net sedimentation coefficients for the same periods were 0.47, 0.22 and 0.30. Our results show that a) empirical models overestimate R during the high loading phase and underestimate R during the transient phase after load reduction, and b) the application of simple one‐box models which assume that a portion of in‐lake P stock is retained requires the consideration of the variability of the net sedimentation coefficient. We identified multiple reasons for variable gross sedimentation (e.g., particle trapping in the elongated lake; efficient accumulation of sewage P) as well as release of P (delayed release of mobile P from sediment; changes in plant colonization and food webs), so that their relation (net sedimentation) varies. Despite a new equilibrium reached in 2003, it is still unclear when the lake will reach mesotrophic reference conditions and a good ecological status. Historical data and elevated Cl– concentration (22 mg L–1) indicate that P import from sewage contaminated groundwater still continues, so that the mean in‐lake P concentration is still too high (53 µg L–1), and biological structures have not fully recovered yet. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polymer coatings that display specific biological signals while preventing nonspecific interactions
Authors: Ameringer Thomas , Fransen Peter , Bean Penny , Johnson Graham , Pereira Suzanne , Evans Richard A. , Thissen Helmut , Meagher Laurence
Published: November 2011

Control over cell‐material surface interactions is the key to many new and improved biomedical devices. It can only be achieved if interactions that are mediated by nonspecifically adsorbed serum proteins are minimized and if cells instead respond to specific ligand molecules presented on the surface. Here, we present a simple yet effective surface modification method that allows for the covalent coupling and presentation of specific biological signals on coatings which have significantly reduced nonspecific biointerfacial interactions. To achieve this we synthesized bottle brush type copolymers consisting of poly(ethylene glycol) methyl ether methacrylate and (meth)acrylates providing activated NHS ester groups as well as different spacer lengths between the NHS groups and the polymer backbone. Copolymers containing different molar ratios of these monomers were grafted to amine functionalized polystyrene cell culture substrates, followed by the covalent immobilization of the cyclic peptides cRGDfK and cRADfK using residual NHS groups. Polymers were characterized by GPC and NMR and surface modification steps were analyzed using XPS. The cellular response was evaluated using HeLa cell attachment experiments. The results showed strong correlations between the effectiveness of the control over biointerfacial interactions and the polymer architecture. They also demonstrate that optimized fully synthetic copolymer coatings, which can be applied to a wide range of substrate materials, provide excellent control over biointerfacial interactions. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Rigid‐CLL: Avoiding constant‐distance computations in cell linked‐lists algorithms
Authors: de Angulo V. Ruiz , Cortés J. , Porta J. M.
Published: November 2011

Many of the existing molecular simulation tools require the efficient identification of the set of nonbonded interacting atoms. This is necessary, for instance, to compute the energy values or the steric contacts between atoms. Cell linked‐lists can be used to determine the pairs of atoms closer than a given cutoff distance in asymptotically optimal time. Despite this long‐term optimality, many spurious distances are anyway computed with this method. Therefore, several improvements have been proposed, most of them aiming to refine the volume of influence for each atom. Here, we suggest a different improvement strategy based on avoiding to fill cells with those atoms that are always at a constant distance of a given atom. This technique is particularly effective when large groups of the particles in the simulation behave as rigid bodies as it is the case in simplified models considering only few of the degrees of freedom of the molecule. In these cases, the proposed technique can reduce the number of distance computations by more than one order of magnitude, as compared with the standard cell linked‐list technique. The benefits of this technique are obtained without incurring in additional computation costs, because it carries out the same operations as the standard cell linked‐list algorithm, although in a different order. Since the focus of the technique is the order of the operations, it might be combined with existing improvements based on bounding the volume of influence for each atom. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2012
Freezing tolerance and low molecular weight cryoprotectants in an invasive parasitic fly, the deer ked (Lipoptena cervi)
Authors: Nieminen Petteri , Paakkonen Tommi , Eerilä Harri , Puukka Katri , Riikonen Joakim , Lehto Vesa‐Pekka , Mustonen Anne‐Mari
Published: November 2011

Insect cold hardiness is often mediated by low molecular weight cryoprotectants, such as sugars, polyols, and amino acids (AA). While many free‐living northern insects must cope with extended periods of freezing ambient temperatures (Ta), the ectoparasitic deer ked Lipoptena cervi imago can encounter subfreezing Ta only during a short autumnal period between hatching and host location. Subsequently, it benefits from the body temperature of the cervid host for survival in winter. This study investigated the cold tolerance of the species by determining its lower lethal temperature (100% mortality, LLT100) during faster and slower cold acclimation, by determining the supercooling point (SCP) and by measuring the concentrations of potential low molecular weight cryoprotectants. The LLT100 of the deer ked was approximately −16°C, which would enable it to survive freezing nighttime Ta not only in its current area of distribution but also further north. The SCP was −7.8°C, clearly higher than the LLT100, indicating that the deer ked displays freezing tolerance. The concentrations of free AA, especially nonessential AA, were higher in the cold‐acclimated deer keds similar to several other insects. The concentrations of proline increased together with γ‐aminobutyrate, arginine, asparagine, cystine, glutamate, glutamine, hydroxylysine, sarcosine, serine, and taurine. AA could be hypothesized to act as cryoprotectants by, e.g., protecting enzymes and lipid membranes from damage caused by cold. J. Exp. Zool. 317:1–8, 2012. © 2011 Wiley Periodicals, Inc.
NONFARM EMPLOYMENT AND INCOMES IN RURAL GHANA
Authors: Ackah Charles
Published: November 2011

This paper analyses the determinants of participation in nonfarm activities and the impact of nonfarm employment on household income. A clear empirical regularity is that women are significantly less likely than men to be in wage employment and more likely than men to be in self‐employment activities. We find also that households whose heads have completed secondary education or higher gravitate more toward wage employment. Nonfarm employment appears to be crucial for the alleviation from rural poverty in Ghana. With limited opportunities in agriculture, nonfarm employment is necessary to augment or supplement farm incomes. Copyright © 2011 John Wiley & Sons, Ltd.
Rapid, sensitive and direct analysis of exopolysaccharides from biofilm on aluminum surfaces exposed to sea water using MALDI‐TOF MS
Authors: Hasan Nazim , Gopal Judy , Wu Hui‐Fen
Published: November 2011

Biofilm studies have extensive significance since their results can provide insights into the behavior of bacteria on material surfaces when exposed to natural water. This is the first attempt of using matrix‐assisted laser desorption/ionization‐mass spectrometry (MALDI‐MS) for detecting the polysaccharides formed in a complex biofilm consisting of a mixed consortium of marine microbes. MALDI‐MS has been applied to directly analyze exopolysaccharides (EPS) in the biofilm formed on aluminum surfaces exposed to seawater. The optimal conditions for MALDI‐MS applied to EPS analysis of biofilm have been described. In addition, microbiologically influenced corrosion of aluminum exposed to sea water by a marine fungus was also observed and the fungus identity established using MALDI‐MS analysis of EPS. Rapid, sensitive and direct MALDI‐MS analysis on biofilm would dramatically speed up and provide new insights into biofilm studies due to its excellent advantages such as simplicity, high sensitivity, high selectivity and high speed. This study introduces a novel, fast, sensitive and selective platform for biofilm study from natural water without the need of tedious culturing steps or complicated sample pretreatment procedures. Copyright © 2011 John Wiley & Sons, Ltd.
Kinetic Modeling of ICAR ATRP
Authors: D'hooge Dagmar R. , Konkolewicz Dominik , Reyniers Marie‐Françoise , Marin Guy B. , Matyjaszewski Krzysztof
Published: November 2011

Kinetic modeling is used to better understand and optimize initiators for continuous activator regeneration atom‐transfer radical polymerization (ICAR ATRP). The polymerization conditions are adjusted as a function of the ATRP catalyst reactivity for two monomers, methyl methacrylate and styrene. In order to prepare a well‐controlled ICAR ATRP process with a low catalyst amount (ppm level), a sufficiently low initial concentration of conventional radical initiator relative to the initial ATRP initiator is required. In some cases, stepwise addition of a conventional radical initiator is needed to reach high conversion. Under such conditions, the equilibrium of the activation/deactivation process for macromolecular species can be established already at low conversion.

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Bivariate simulation using copula and its application to probabilistic pile settlement analysis
Authors: Li Dian‐Qing , Tang Xiao‐Song , Phoon Kok‐Kwang , Chen Yi‐Feng , Zhou Chuang‐Bing
Published: November 2011

This paper aims to propose a procedure for modeling the joint probability distribution of bivariate uncertain data with a nonlinear dependence structure. First, the concept of dependence measures is briefly introduced. Then, both the Akaike Information Criterion and the Bayesian Information Criterion are adopted for identifying the best‐fit copula. Thereafter, simulation of copulas and bivariate distributions based on Monte Carlo simulation are presented. Practical application for serviceability limit state reliability analysis of piles is conducted. Finally, four load–test datasets of load–displacement curves of piles are used to illustrate the proposed procedure. The results indicate that the proposed copula‐based procedure can model and simulate the bivariate probability distribution of two curve‐fitting parameters underlying the load–displacement models of piles in a more general way. The simulated load–displacement curves using the proposed procedure are found to be in good agreement with the measured results. In most cases, the Gaussian copula, often adopted out of expedience without proper validation, is not the best‐fit copula for modeling the dependence structure underlying two curve‐fitting parameters. The conditional probability density functions obtained from the Gaussian copula differ considerably from those obtained from the best‐fit copula. The probabilities of failure associated with the Gaussian copula are significantly smaller than the reference solutions, which are very unconservative for pile safety assessment. If the strong negative correlation between the two curve‐fitting parameters is ignored, the scatter in the measured load–displacement curves cannot be simulated properly, and the probabilities of failure will be highly overestimated. Copyright © 2011 John Wiley & Sons, Ltd.
Health Consequences of Obesity
Authors: Berenson Gerald S. ,   for the Bogalusa Heart Study group
Published: November 2011

Epidemiologic studies have established that cardiovascular (CV) risk factors including obesity are identifiable in childhood. Childhood risk factors are predictive of adult cardiac risk and even premature death [Franks et al. (2010) N Engl J Med 362:485–493]. In the United States, CV diseases remains the leading causes of death. In fact, heart disease has become the major cause of death worldwide, surpassing undernutrition and infectious diseases, largely related to obesity in childhood [Wang and Lobstein (2006) Int J Pediatr Obes 1:11–25]. The concept that adult heart diseases begin in childhood is an outgrowth of extensive long‐term epidemiologic studies in youth, that is, the Bogalusa Heart Study [Berenson et al. (1986) Causation of cardiovascular risk factors in children: Perspectives on cardiovascular risk in early life, Raven Press Books Ltd]. Pediatr Blood Cancer 2012; 58: 117–121. © 2011 Wiley Periodicals, Inc.
Is the distribution grid ready to accept large‐scale photovoltaic deployment? State of the art, progress, and future prospects
Authors: Braun Martin , Stetz Thomas , Bründlinger Roland , Mayr Christoph , Ogimoto Kazuhiko , Hatta Hiroyuki , Kobayashi Hiromu , Kroposki Ben , Mather Barry , Coddington Michael , Lynn Kevin , Graditi Giorgio , Woyte Achim , MacGill Iain
Published: November 2011

The installed capacity of photovoltaic (PV) systems has recently increased at a much faster rate than the development of grid codes to effectively and efficiently manage high penetrations of PV within the distribution system. In a number of countries, PV penetrations in some regions are now raising growing concerns regarding integration. Management strategies vary considerably by country—some still have an approach that PV systems should behave as passive as possible, whereas others demand an active participation in grid control. This variety of grid codes also causes challenges in learning from “best practice.” This paper provides a review of current grid codes in some countries with high PV penetrations. In addition, the paper presents a number of country‐specific case studies on different approaches for improved integration of PV systems in the distribution grid. In particular, we consider integration approaches using active and reactive power control that can reduce or defer expensive grid reinforcement while supporting higher PV penetrations. Copyright © 2011 John Wiley & Sons, Ltd.
Photodynamic Therapy of Pheophorbide a Inhibits the Proliferation of Human Breast Tumour via Both Caspase‐dependent and ‐independent Apoptotic Pathways in In Vitro and In Vivo Models
Authors: Hoi Sandy Wan‐Heng , Wong Hoi Ming , Chan Judy Yuet‐Wa , Yue Grace Gar Lee , Tse Gary Man‐Kit , Law Bonita Ka‐Bo , Fong Wing Ping , Fung Kwok Pui
Published: November 2011

Breast cancer is conventionally treated by surgery and radiotherapy, with adjuvant chemotherapy and hormonotherapy as supplementary treatments. However, such treatments are associated with adverse side effects and drug resistance. In this study, Pheophorbide a (Pa), a photosensitizer isolated from Scutelleria barbata, was analysed for its antiproliferative effect on human breast tumour cells. The IC (inhibitory concentration)50 of the combined treatment of Pa and photodynamic therapy (Pa‐PDT) on human breast tumour MCF‐7 cells was 0.5 µm. Mechanistic studies in MCF‐7 cells demonstrated that Pa was localized in the mitochondria, and reactive oxygen species were found to be released after Pa‐PDT. Apoptosis was the major mechanism responsible for the tumour cell death, and mitochondrial membrane depolarization and cytochrome c release highlighted the role of mitochondria in the apoptotic mechanism. Up‐regulation of tumour suppressor protein p53, cleavage of caspase‐9 and poly (ADP‐ribose) polymerase suggested that the caspase‐dependent pathway was induced, while the release of apoptosis‐inducing factors demonstrated that the apoptosis was also mediated by the caspase‐independent mechanism. In vivo study using the mouse xenograft model showed a significant inhibition of MCF‐7 tumour growth by Pa‐PDT. Together, the results of this study provide a basis for understanding and developing Pa‐PDT as a cure for breast cancer. Copyright © 2011 John Wiley & Sons, Ltd.
The Beetroot Component Betanin Modulates ROS Production, DNA Damage and Apoptosis in Human Polymorphonuclear Neutrophils
Authors: Zielińska‐Przyjemska Małgorzata , Olejnik Anna , Kostrzewa Artur , Łuczak Michał , Jagodziński Paweł P. , Baer‐Dubowska Wanda
Published: November 2011

The aim of this study was to evaluate the effect of betanin, one of the beetroot major components, on ROS production, DNA damage and apoptosis in human resting and stimulated with phorbol 12‐myristate13‐acetate polymorphonuclear neutrophils, one of the key elements of the inflammatory response.

Incubation of neutrophils with betanin in the concentration range 2–500 µm resulted in significant inhibition of ROS production (by 15–46%, depending on the ROS detection assay). The antioxidant capacity of betanin was most prominently expressed in the chemiluminescence measurements. This compound decreased also the percentage of DNA in comet tails in stimulated neutrophils, but only at the 24 h time point. In resting neutrophils an increased level of DNA in comet tails was observed. Betanin did not affect the activity of caspase‐3, in resting neutrophils, but significantly enhanced the enzyme activity in stimulated neutrophils. The western blot analysis showed, however, an increased level of caspase‐3 cleavage products as a result of betanin treatment both in resting and stimulated neutrophils. The results indicate that betanin may be responsible for the effect of beetroot products on neutrophil oxidative metabolism and its consequences, DNA damage and apoptosis. The dose and time dependent effects on these processes require further studies. Copyright © 2011 John Wiley & Sons, Ltd.
The Brewer–Dobson circulation inferred from ERA‐Interim
Authors: Seviour William J. M. , Butchart Neal , Hardiman Steven C.
Published: November 2011

The transformed Eulerian mean residual circulation is calculated from ERA‐Interim for 1989–2009. Known as the Brewer–Dobson circulation, this measures the tropical upwelling of mass from troposphere to stratosphere, the mean meridional mass transport in the stratosphere and the downwelling of mass in the Extratropics. Major features of the Brewer–Dobson circulation, including the seasonal migration of the tropical upwelling toward the summer pole, are well represented. In the tropical lower stratosphere vertical velocities are less noisy than in other reanalyses, though significant tidal variations demonstrate the need for 6‐hourly data. Throughout the year tropical lower stratospheric ascent rates are a minimum at the Equator and strongest in the Northern Hemisphere. In each hemisphere the maximum tropical ascent occurs during summer, whereas the strongest circulation and maximum in extratropical descent occur in the winter hemisphere. At 70 hPa the annual mean upwelling mass flux is 5.9 × 109 kg s−1, with the zonal drag from resolved waves and parametrized orographic gravity wave drag (OGWD) providing 70% and 4% of the driving, respectively. Hence it is concluded that the OGWD probably underestimates the momentum deposited above 70 hPa in addition to there being an absence of drag from non‐orographic gravity waves. A statistically significant trend of −5% per decade in the upwelling mass flux is considered unreliable because it is inconsistent with the negative temperature trend, assuming a mainly adiabatic temperature response at this level (70 hPa) to the changes in upwelling. Copyright © 2011 British Crown copyright, the Met Office. Published by John Wiley & Sons Ltd.
Detection of Erythrocytes in Patient With Iron Deficiency Anemia Using Atomic Force Microscopy
Authors: Zhang Yuping , Zhang Wei , Wang Shunqing , Wang Caixia , Xie Jianjin , Chen Xiaoyan , Xu Yanli , Mao Ping
Published: November 2011

Purpose

Iron deficiency anemia (IDA) disturbs the morphology and function of erythrocytes at molecular level. The purpose of this study was to show that pathophysiological changes to erythrocytes could be detected at the nanometer scale, which is important for the early diagnosis and effective therapies of the anemia.

Methods

Blood samples were taken from six healthy volunteers and six patients with IDA before and after therapy. Changes in the morphological and biomechanical properties of erythrocytes were studied at the nanometer level using atomic force microscopy (AFM).

Results

There were dramatic overall shape and surface membrane deformations of the erythrocytes associated with pre‐ and post‐therapeutic IDA compared with healthy erythrocytes. Healthy and pathological erythrocytes of IDA could be distinguished by the morphologic parameters of width, length, the ratio of length to width, valley, peak, valley‐to‐peak, standard deviations, and surface fluctuation. Treatment effectiveness also could be evaluated by these parameters.

Conclusions

AFM is a good tool for IDA study. Erythrocyte morphology is an important determinant for diagnosing and evaluating therapeutic effect of IDA disease. SCANNING 34: 215‐220, 2012. © 2011 Wiley Periodicals, Inc.
How long must a firm be great to rule out chance? Benchmarking sustained superior performance without being fooled by randomness
Authors: Henderson Andrew D. , Raynor Michael E. , Ahmed Mumtaz
Published: November 2011

Although sustained superior firm performance may arise from skillful management or other valuable, rare, and inimitable resources, it can also result from randomness. Studying U.S. companies from 1965–2008, we benchmark how long a firm must perform at a high level to be confident that it is something other than the outcome of a time‐homogeneous stationary Markov chain defined on the state space of percentiles. We find (a) the number of sustained superior performers in Compustat, measured by ROA and Tobin's q, exceeds the number of false positives we would expect to be generated by such a process; yet (b) the occurrence of false positives is often enough to fool many observers, so (c) the identification of sustained superior performers requires particularly stringent benchmarks to enable valid study. Copyright © 2011 John Wiley & Sons, Ltd.
In vitro models
Authors: Mather Jennie Powell
Published: November 2011

The current resurgence of interest in the cancer stem cell (CSC) hypothesis as possibly providing a unifying theory of cancer biology is fueled by the growing body of work on normal adult tissue stem cells and the promise that CSC may hold the key to one of the central problems of clinical oncology: tumor recurrence. Many studies suggest that the microenvironment plays a role, perhaps a seminal one, in cancer development and progression. In addition, the possibility that the stem cell-like component of tumors is capable of rapid and reversible changes of phenotype raises questions concerning studies with these populations and the application of what we learn to the clinical situation. These types of questions are extremely difficult to study using in vivo models or freshly isolated cells. Established cell lines grown in defined conditions provide important model systems for these studies. There are three types of in vitro models for CSCs: (a) selected subpopulations of existing tumor lines (derived from serum-containing medium; (b) creation of lines from tumor or normal cells by genetic manipulation; or (c) direct in vitro selection of CSC from tumors or sorted tumor cells using defined serum-free conditions. We review the problems associated with creating and maintaining in vitro cultures of CSCs and the progress to date on the establishment of these important models.

Disclosure of potential conflicts of interest is found at the end of this article.
5-Aminoimidazole-4-carboxyamide Ribonucleoside Induces G1/S Arrest and Nanog Downregulation via p53 and Enhances Erythroid Differentiation
Authors: Chae Hee-Don , Lee Man-Ryul , Broxmeyer Hal E.
Published: November 2011

Molecular mechanisms of how energy metabolism affects embryonic stem cell (ESC) pluripotency remain unclear. AMP-activated protein kinase (AMPK), a key regulator for controlling energy metabolism, is activated in response to ATP-exhausting stress. We investigated whether cellular energy homeostasis is associated with maintenance of self-renewal and pluripotency in mouse ESCs (mESCs) by using 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) as an activator of AMPK. We demonstrate that AICAR treatment activates the p53/p21 pathway and markedly inhibits proliferation of R1 mESCs by inducing G1/S-phase cell cycle arrest, without influencing apoptosis. Treatment with AICAR also significantly reduces pluripotent stem cell markers, Nanog and stage-specific embryonic antigen-1, in the presence of leukemia inhibitory factor, without affecting expression of Oct4. H9 human ESCs also responded to AICAR with induction of p53 activation and repression of Nanog expression. AICAR reduced Nanog mRNA levels in mESCs transiently, an effect not due to expression of miR-134 which can suppress Nanog expression. AICAR induced Nanog degradation, an effect inhibited by MG132, a proteasome inhibitor. Although AICAR reduced embryoid body formation from mESCs, it increased expression levels of erythroid cell lineage markers (Ter119, GATA1, Klf1, Hbb-b, and Hbb-bh1). Although erythroid differentiation was enhanced by AICAR, endothelial lineage populations were remarkably reduced in AICAR-treated cells. Our results suggest that energy metabolism regulated by AMPK activity may control the balance of self-renewal and differentiation of ESCs.

Disclosure of potential conflicts of interest is found at the end of this article.
A novel sine‐curve mobility model for intrusion detection in wireless sensor networks
Authors: Wang Yun , Leow Yoon Kah , Yin Jun
Published: November 2011

Intrusion detection is prominently important for civil and military applications in wireless sensor networks (WSNs). To date, related works address the problem by assuming a straight‐line intrusion path and a Boolean sensing model. However, a straight‐line intrusion path is often not the case in reality, and the Boolean sensing model cannot resemble a real‐world sensor precisely. Results based on these assumptions are therefore not applicable with desirable accuracy in practice. In view of this, we propose a novel sine‐curve mobility model that can simulate different intrusion paths by adjusting its features (amplitude, frequency, and phase) and can be integrated into the random WSN model for intrusion detection analysis. It can also be applied to different sensor models and makes influencing factors tractable. With the model, we examine the effects of different intrusion paths on the intrusion detection probability in a random WSN, considering both Boolean and realistic Elfes sensing models. Further, we investigate the interplays between network settings and intruder's mobility patterns and identify the benefits and side effects of the model theoretically and experimentally. Simulation outcomes are shown to match well with the theoretical results, validating the modeling, analysis, and conclusions. Copyright © 2011 John Wiley & Sons, Ltd.
Von der Schwierigkeit, „Landschaft“ oder „Kulturlandschaft“ allgemeingültig zu definieren
Authors: Gailing Ludger , Leibenath Markus
Published: November 2011

Instead of striving to define ‘landscape’ and ‘cultural landscape’ universally, the contribution highlights the multiple perspectives from which these terms might be regarded: They are valuable in academic and practical contexts exactly because they can carry heterogeneous meanings, because they evoke positive connotations and because they can tie together diverse approaches in spatial research. The article is intended to identify and describe central positions by pairs in the semantic fields of ‘landscape’ which are fraught with tension. The elements of each pair, e.g. normative versus descriptive or subjective versus objective notions of landscape, are to be understood as opposed poles between which productive frictions can arise. Furthermore the semantic differences between ‘landscape’, ‘cultural landscape’ and the related terms ‘space’ and ‘culture’ are discussed. The authors adopt a moderate constructivist perspective, which can be characterized as discourse-analytical in a wider sense: By analyzing and systematizing how other scholars employ ‘landscape’ and ‘cultural landscape’ and how they define them in relation to other terms, the authors present second-order observations. One finding is that the constitution of the meaning of the words ‘landscape’ and ‘cultural landscape’ always is a matter of perspective: It is crucial from which academic perspective (second level of observation) which processes of ascribing meaning (first level of observation) are studied.
Prognostic Significance of Weight Changes during Treatment of Feline Lymphoma
Authors: Krick Erika L , Moore Reneé H , Cohen Rachel B , Sorenmo Karin U
Published: November 2011

The study purpose was to determine the prognostic significance of weight changes during feline lymphoma treatment. A secondary purpose was to compare weight changes according to baseline body weight, cell type and location. Records of 209 cats treated for lymphoma with chemotherapy from 1995 to 2007 were evaluated. Signalment, cell type, lymphoma location, baseline body weight, weight during treatment, and outcome information were collected. Lymphoma specific survival (LSS) was compared according to baseline weight and weight changes during treatment. Weight change over time was compared according to cell type (small versus large), location (gastrointestinal versus non-gastrointestinal) and baseline weight. Cats with large cell lymphoma that lost ≥5% body weight at 1 month had significantly shorter LSS than those that gained or had stable weight ( P = 0.004). Percentage weight change over time differed significantly according to baseline weight group. These findings demonstrate the prognostic importance of weight loss in feline large cell lymphoma.
Drugs as instruments: A new framework for non-addictive psychoactive drug use
Authors: Müller Christian P. , Schumann Gunter
Published: November 2011

Most people who are regular consumers of psychoactive drugs are not drug addicts, nor will they ever become addicts. In neurobiological theories, non-addictive drug consumption is acknowledged only as a “necessary” prerequisite for addiction, but not as a stable and widespread behavior in its own right. This target article proposes a new neurobiological framework theory for non-addictive psychoactive drug consumption, introducing the concept of “drug instrumentalization.” Psychoactive drugs are consumed for their effects on mental states. Humans are able to learn that mental states can be changed on purpose by drugs, in order to facilitate other, non-drug-related behaviors. We discuss specific “instrumentalization goals” and outline neurobiological mechanisms of how major classes of psychoactive drugs change mental states and serve non-drug-related behaviors. We argue that drug instrumentalization behavior may provide a functional adaptation to modern environments based on a historical selection for learning mechanisms that allow the dynamic modification of consummatory behavior. It is assumed that in order to effectively instrumentalize psychoactive drugs, the establishment of and retrieval from a drug memory is required. Here, we propose a new classification of different drug memory subtypes and discuss how they interact during drug instrumentalization learning and retrieval. Understanding the everyday utility and the learning mechanisms of non-addictive psychotropic drug use may help to prevent abuse and the transition to drug addiction in the future.
Drug use as consumer behavior
Authors: Foxall Gordon Robert , Sigurdsson Valdimar
Published: November 2011

Seeking integration of drug consumption research by a theory of memory function and emphasizing drug consumption rather than addiction, Müller & Schumann (M&S) treat drug self-administration as part of a general pattern of consumption. This insight is located within a more comprehensive framework for understanding drug use as consumer behavior that explicates the reinforcement contingencies associated with modes of drug consumption.
Flaws of drug instrumentalization
Authors: Swendsen Joel , Le Moal Michel
Published: November 2011

The adaptive use of drugs, or “drug instrumentalization,” is presented as a reality that the scientific literature has largely ignored. In this commentary, we demonstrate why this concept has limited value from the standpoint of nosology, why it should not be viewed as “adaptive,” and why it has dangerous implications for policy and public health efforts.
Optimal drug use and rational drug policy
Authors: Miller Geoffrey F.
Published: November 2011

The Müller & Schumann (M&S) view of drug use is courageous and compelling, with radical implications for drug policy and research. It implies that most nations prohibit most drugs that could promote happiness, social capital, and economic growth; that most individuals underuse rather than overuse drugs; and that behavioral scientists could use drugs more effectively in generating hypotheses and collaborating empathically.
Drug addiction finds its own niche
Authors: Reid Alastair
Published: November 2011

The evolutionary framework suggested by Müller & Schumann (M&S) can be extended further by considering drug-taking in terms of Niche Construction Theory (NCT). It is suggested here that genetic and environmental components of addiction are modified by cultural acceptance of the advantages of non-addicted drug taking and the legitimate supply of performance-enhancing drugs. This may then reduce the prevalence of addiction.
Multiple Double Cross-Section Transmission Electron Microscope Sample Preparation of Specific Sub-10 nm Diameter Si Nanowire Devices
Authors: Gignac Lynne M. , Mittal Surbhi , Bangsaruntip Sarunya , Cohen Guy M. , Sleight Jeffrey W.
Published: November 2011

The ability to prepare multiple cross-section transmission electron microscope (XTEM) samples from one XTEM sample of specific sub-10 nm features was demonstrated. Sub-10 nm diameter Si nanowire (NW) devices were initially cross-sectioned using a dual-beam focused ion beam system in a direction running parallel to the device channel. From this XTEM sample, both low- and high-resolution transmission electron microscope (TEM) images were obtained from six separate, specific site Si NW devices. The XTEM sample was then re-sectioned in four separate locations in a direction perpendicular to the device channel: 90° from the original XTEM sample direction. Three of the four XTEM samples were successfully sectioned in the gate region of the device. From these three samples, low- and high-resolution TEM images of the Si NW were taken and measurements of the NW diameters were obtained. This technique demonstrated the ability to obtain high-resolution TEM images in directions 90° from one another of multiple, specific sub-10 nm features that were spaced 1.1 μm apart.
Chemical clues on the formation of planetary systems
Authors: Mena Elisa Delgado , Israelian Garik , Hernández Jonay I. González , Bond Jade C. , Santos Nuno C. , Udry Stéphane , Mayor Michel
Published: November 2011

Theoretical studies suggest that C/O and Mg/Si are the most important elemental ratios in determining the mineralogy of terrestrial planets. The C/O ratio controls the distribution of Si among carbide and oxide species, while Mg/Si gives information about the silicate mineralogy. We find mineralogical ratios quite different from those of the Sun, showing that there is a wide variety of planetary systems which are not similar to Solar System. Many of planetary host stars present a Mg/Si value lower than 1, so their planets will have a high Si content to form species such as MgSiO3. This type of composition can have important implications for planetary processes like plate tectonics, atmospheric composition or volcanism. Moreover, the information given by these ratios can guide us in the search of stars more probable to form terrestrial planets.
Application of recent results on the orbital migration of low mass planets: convergence zones
Authors: Mordasini Christoph , Dittkrist Kai-Martin , Alibert Yann , Klahr Hubert , Benz Willy , Henning Thomas
Published: November 2011

Previous models of the combined growth and migration of protoplanets needed large ad hoc reduction factors for the type I migration rate as found in the isothermal approximation. In order to eliminate these factors, a simple semi-analytical model is presented that incorporates recent results on the migration of low mass planets in non-isothermal disks. It allows for outward migration. The model is used to conduct planetary populations synthesis calculations. Two points with zero torque are found in the disks. Planets migrate both in- and outward towards these convergence zones. They could be important for accelerating planetary growth by concentrating matter in one point. We also find that the updated type I migration models allow the formation of both close-in low mass planets, but also of giant planets at large semimajor axes. The problem of too rapid migration is significantly mitigated.
A new view on planet formation
Authors: Nayakshin Sergei
Published: November 2011

The standard picture of planet formation posits that giant gas planets are over-grown rocky planets massive enough to attract enormous gas atmospheres. It has been shown recently that the opposite point of view is physically plausible: the rocky terrestrial planets are former giant planet embryos dried of their gas “to the bone” by the influences of the parent star. Here we provide a brief overview of this “Tidal Downsizing” hypothesis in the context of the Solar System structure.
A possible dividing line between massive planets and brown-dwarf companions
Authors: Sahlmann Johannes , Ségransan Damien , Queloz Didier , Udry Stéphane
Published: November 2011

Brown dwarfs are intermediate objects between planets and stars. The lower end of the brown-dwarf mass range overlaps with the one of massive planets and therefore the distinction between planets and brown-dwarf companions may require to trace the individual formation process. We present results on new potential brown-dwarf companions of Sun-like stars, which were discovered using CORALIE radial-velocity measurements. By combining the spectroscopic orbits and Hipparcos astrometric measurements, we have determined the orbit inclinations and therefore the companion masses for many of these systems. This has revealed a mass range between 25 and 45 Jupiter masses almost void of objects, suggesting a possible dividing line between massive planets and sub-stellar companions.
Statistical patterns in ground-based transit surveys
Authors: Cameron Andrew Collier
Published: November 2011

As the number of known transiting planets from ground-based surveys passes the 100 mark, it is becoming possible to perform meaningful statistical analyses on their physical properties. Caution is needed in their interpretation, because subtle differences in survey strategy can lead to surprising selection effects affecting the distributions of planetary orbital periods and radii, and of host-star metallicity. Despite these difficulties, the planetary mass-radius relation appears to conform more or less to theoretical expectations in the mass range from Saturns to super-Jupiters. The inflated radii of many hot Jupiters indicate that environmental factors can have a dramatic effect on planetary structure, and may even lead to catastrophic loss of the planetary envelope under extreme irradiation. High-precision radial velocities and secondary-eclipse timing are yielding eccentricity measurements of exquisite precision. They show some hot Jupiters to be in almost perfectly circular orbits, while others remain slightly but significantly eccentric.
The spectra of low-temperature atmospheres: Lessons learned from brown dwarfs
Authors: Burgasser Adam J.
Published: November 2011

Indirect and direct spectroscopic studies of exoplanets are beginning to probe the most prominent chemical constituents and processes in their atmospheres. However, studies of equivalently low-temperature brown dwarfs have been taking place for over a decade. In this review, I summarize some of the results of detailed spectroscopic, photometric and polarimetric studies of brown dwarfs of various effective temperatures, surface gravities and metallicities, highlighting the insight gained into the chemistry and cloud formation of planetary-like atmospheres. Nonequilibrium chemistry and variations in cloud properties are singled out as critical ingredients for interpreting exoplanet spectra. I also discuss recent direct spectroscopic studies of exoplanet atmospheres, both close to and widely-separated from their host star, and propose that the latter are better analogs to isolated brown dwarfs.
Tidal dynamics of transiting exoplanets
Authors: Fabrycky Daniel C.
Published: November 2011

Transits give us the mass, radius, and orbital properties of the planet, all of which inform dynamical theories. Two properties of the hot Jupiters suggest they had a dramatic origin via tidal damping from high eccentricity. First, the tidally circularized planets (in the 1-4 day pile-up) lie along a relation or boundary in the mass-period plane. This observation may implicate a tidal damping process regulated by planetary radius inflation and Roche lobe overflow, early in the planets' lives. Second, the host stars of many planets have spins misaligned from the planets' orbits. This observation was not expected a priori from the conventional disk migration theory, and it was a boon for the alternative theories of planet-planet scattering and Kozai cycles, accompanied by tidal friction, which predicted it. Now we are faced with a curious observation that the misalignment angle depends on the stellar temperature. It may mean that the tide raised on the stars realigns them, the final result being the tidal consumption of hot Jupiters.
Direct imaging of massive extrasolar planets
Authors: Kalas Paul
Published: November 2011

The direct detection of an extrasolar planet can provide accurate measurements of its orbit, mass and composition, greatly improving our understanding of how planets form and evolve. Recent advances in ground-based and space-based imaging techniques have now produced the first direct images of extrasolar planets. Typically these are many-Jupiter-mass planets on wide orbits. Direct imaging therefore probes the outer architecture of planetary systems and it is highly complementary to other techniques sensitive to inner architectures. This brief review summarizes the properties of the currently imaged exoplanets, provides an update on the orbit of Fomalhaut b, and highlights the emerging phenomenon of circumplanetary disks.
On the equilibrium rotation of Hot Jupiters in eccentric and excited orbits
Authors: Correia Alexandre C. M.
Published: November 2011

Hot-Jupiters are a common sub-class of exoplanets, which are enough close to the star to undergo tidal dissipation. The continuous action of tides modify the rotation of the planets until an equilibrium situation is reached. It is often assumed that synchronous motion is the most probable outcome of tidal evolution, since synchronous rotation is observed for the majority of the satellites in the Solar System. This is true for circular orbits, but when the orbits are eccentric, tidal effects are stronger when the planets are closer to the star, and therefore, the rotation rate tends to equalize the orbital speed rate at the pericenter (which is faster than synchronous rotation). An additional complication arises if the eccentricity is not constant and undergoes periodic perturbations from an external companion. Here we obtain an expression for the equilibrium rotation of Hot-Jupiters undergoing tidal dissipation and planetary perturbations. We show that for these planets, the equilibrium rotation rate is faster than for non-perturbed eccentric orbits.
On the possibility of enrichment and differentiation in gas giants during birth by disk instability
Authors: Boley Aaron C. , Durisen Richard H.
Published: November 2011

We investigate the coupling between solids and gas during the formation of gas giant planets by disk fragmentation in the outer regions of massive disks. We find that fragments can become differentiated at birth. Even if an entire clump does not survive, differentiation could create solids cores that survive to accrete gaseous envelopes later.
Simultaneous formation of Jupiter and Saturn
Authors: Guilera Octavio M. , Brunini Adrián , Benvenuto Omar G.
Published: November 2011

We calculate the simultaneous in situ formation of Jupiter and Saturn by the core instability mechanism considering the oligarchic growth regime for the accretion of planetesimals. We consider a density distribution for the size of planetesimals and planetesimals migration. The planets are immersed in a realistic protoplanetary disk that evolves with time. We find that, within the classical model of solar nebula, the isolated formation of Jupiter and Saturn undergoes significant change when it occurs simultaneously.
Dead zones and the diversity of exoplanetary systems
Authors: Hasegawa Yasuhiro , Pudritz Ralph E.
Published: November 2011

Planetary migration provides a theoretical basis for the observed diversity of exoplanetary systems. We demonstrate that dust settling - an inescapable feature of disk evolution - gives even more rapid type I migration by up to a factor of about 2 than occurs in disks with fully mixed dust. On the other hand, type II migration becomes slower by a factor of 2 due to dust settling. This even more problematic type I migration can be resolved by the presence of a dead zone; the inner, high density region of a disk which features a low level of turbulence. We show that enhanced dust settling in the dead zone leaves a dusty wall at its outer edge. Back-heating of the dead zone by this wall produces a positive radial gradient for the disk temperature, which acts as a barrier for type I migration.
The GROUnd-based Secondary Eclipse project - GROUSE
Authors: de Mooij Ernst , de Kok Remco , Nefs Bas , Brogi Matteo , Snellen Ignas
Published: November 2011

Secondary eclipse observations of exoplanets at near-infrared wavelengths are important to constrain the energy budgets of hot-Jupiters, since they probe the radiation from the planet's atmosphere at the peak of the spectral energy distribution. Since this wavelength range is accesible from the ground, we have started the GROUnd-based Secondary Eclipse (GROUSE) project. As part of the GROUSE project, we target a sample of hot-Jupiters at near-infrared and optical wavelengths. Planets include TrES-3b, HAT-P-1, WASP-18b and WASP-33b.