bluuebunny/crossref_metadata_2025 huggingface dataset:
Spring Break Travel: Thirty Years of Scholarly Evidence, 1980–2010
Authors: Ribeiro Nuno F. , Hickerson Benjamin D.
Published: April 2013

Spring break is a week-long North American collegiate travel vacation period that draws hundreds of thousands of young tourists to a few select tourism destinations, and has become a topic of growing social and economic importance. In spite of a rising interest by tourism scholars,
most of the spring break literature remains dispersed through a wide variety of outlets and disciplines. Moreover, critical appraisals of the current spring break literature in light of the wider phenomenon of youth tourism are absent. The present study presents an integrative and comprehensive
assessment of extant spring break literature for the 30-year period of 1980–2010. Our findings identified literature focusing primarily on college students' motivations and behavior while on spring break, with an emphasis on risky health behaviors such as alcohol consumption and unprotected
sex. The majority of the studies surveyed relied heavily on quantitative approaches of data collection and analysis. This review found numerous discrepancies in regard to spring breakers' previous intentions, motivations, behavior, involvement in the spring break experience, and factors affecting
spring break behavior. This review highlighted the complexity of the spring break phenomenon, as well as the necessity of moving beyond the "Spring bacchanal" paradigm. Directions for future research based upon contradictions and/or gaps identified in the literature are discussed.
Comparing Customer Ratings from Multiple Reputation Systems: The Case of New York City Hotels
Authors: Sanford Douglas , Otto James
Published: April 2013

This exploratory study analyzes the customer ratings of hotels across multiple reputation systems: Expedia, Orbitz, and travelocity. We investigate the extent to which the websites' customer ratings for overall satisfaction are equivalent. Our analysis of a random sample of 99 hotels
in New York City and 5,575 individual customer ratings suggests that the ratings are not equivalent across websites, and that each website's customer ratings offers unique information on the ability of hotels to satisfy customers. We discuss how this finding affects strategies for users to
combine the ratings and implications for consumers, hotel managers, and website administrators.
Casino Travel Motivations of Chinese Tourists: Differences in Visitation Attributes
Authors: Anthony Wong Ipkin
Published: April 2013

Tourism scholars have identified a need to understand why Chinese like to visit casinos and to segment tourists' travel motivation by their visitation characteristics. The principal purpose of this article is to explore Chinese tourists' travel motivations to casinos and to seek differences
in visit frequency and length. Based on a sample of mainland Chinese tourists in Macau, the world gambling capital, the results indicate significant differences between first-time and repeat tourists in respect to casino and gambling experience seeking, socialization, and accessibility. The
results also suggest that Chinese tourists' length of stay is primarily contingent on their desire to escape from pressure and mundane life. In light of these findings, managerial and theoretical implications are discussed.
Development and multiplexed amplification of SSR markers for Thuja occidentalis (Cupressaceae) using shotgun pyrosequencing
Authors: Xu Huaitong , Tremblay Francine , Bergeron Yves
Published: April 2013

• Premise of the study: Sixteen novel, polymorphic, multiplexed microsatellite loci were developed for eastern white cedar (Thuja occidentalis) using simple sequence repeat (SSR)–enriched shotgun pyrosequencing.

• Methods and Results: Sixteen loci were tested on a panel of 24 individuals from different populations. The number of observed alleles ranged from four to 22. Four sets of multiplex PCR for the 16 loci were then carried out on 60 individuals of two populations from islands of FERLD Duparquet Forest, Canada. Mean number of alleles, observed heterozygosity, and expected heterozygosity were respectively 5.75, 0.594, and 0.574 for Island 58, and 5.50, 0.704, and 0.624 for Island 134.

• Conclusions: Four sets of multiplex microsatellite loci can be used for future genetic studies, which includes investigating genetic diversity and structure, and fragmentation and regeneration studies.
Classification of Iberian pigs according to intensive feeding by chemsensor
Authors: Carrasco J. A. , Duque J. P.
Published: April 2013

Pork quality is highly dependent on intensive feeding during the fattening step. For that reason a large number of analytical methods are continuously being developed to evaluate it. Among them is the ChemSensor method which comprises a multivariate analysis in a gas chromatograph with a mass spectrometry detection device. This technique affords a feeding grouping of similar features, leading to a classification of meat quality. Using a mathematical predictive model for new, unknown samples the right classification is achieved as well as the type of intensive feeding used during the fattening of pigs. Pigs from two campaignes have been classificated with good results, although a certain difficulty in prediction was found due to the excessively large number of classes stated in the official Quality Iberian Standards, and the customs of the farmers themselves in relation with the handling of animals and the intensive feeding provided. Narrowing the number of classes down to two, “Bellota” and “Pienso”, would contribute to a better understanding in the Iberian pig market.
GC-C-IRMS analysis of FAMEs as a tool to ascertain the diet of Iberian pigs used for the production of pork products with high added value
Authors: Recio C. , Martín Q. , Raposo C.
Published: April 2013

Taste, quality and perceived health benefits result in a high demand for both green and mature pork products derived from the Iberian bred swine. These characteristics are directly related to diet and breeding style (free ranging in a particular Mediterranean ecosystem: the Dehesa). Given that current demand is not matched by the available resources, animal feed is increasingly used. GC-C-IRMS analysis of Palmitic, Stearic, Oleic and Linoleic Acid methyl esters allows for differentiating between pork raised in the traditional way and that fattened on animal feed. Although a value of δ13CC18:1 = –25.9‰ is a good discriminator, exploratory analysis of principal canonical components is required to properly assign any unknown sample.
Chemical-instrumental-sensory parameters and chemometrics as tools to discriminate among the quality categories of dry-cured Iberian shoulder
Authors: Silva A. , Reina R. , García-Casco J. , Ventanas J.
Published: April 2013

A combination of physico-chemical and sensory measurements along with chemometric tools was used to authenticate the quality category of dry-cured Iberian shoulder. Depending on the confinement regime and feeding background, dry-cured Iberian shoulders from three classes were analyzed: i) pigs reared in confinement regime and fed with commercial feeds (CON class), ii) pigs reared in extensive regime and fed with commercial feeds (EXT class) and iii) pigs reared in extensive regime and fed with natural sources (grass and acorns), called Montanera regime (MON class). The principal component analysis (PCA) results discriminated among the three types of dry-cured shoulders according to their quality. The soft independent modelling of class analogy (SIMCA), which is a classification model, enabled the characterization of the quality class of unknown dry-cured shoulder samples. Finally the Cooman´s plot and Si vs. Hi plot provide a classification for the unknown quality of dry-cured shoulders.
PERSONALIZED TRAITS MONITORING USING A NEURAL NETWORK BASED ON OSCILLOMETRIC MEASUREMENTS
Authors: Shin Young-Suk
Published: April 2013

Oscillometric method uses a pressure sensor instead of a stethoscope to record the pressure oscillations within the cuff. Oscillations observed from the pressure sensor show personalized traits of systolic pressure, which indicates the maximum amount of work the heart has to perform per stroke in order to move blood through the arteries. For a given person, the oscillation waveforms extracted from the cuff pressure have an oscillation pattern that varies in size over time. Thus, to extract uniform features from a given person, we normalize the variability of the corresponding oscillation patterns for different frequencies, and evaluate systolic blood pressure using a feedforward neural network based on the extracted features. The validity of measuring systolic blood pressure with a neural network was compared with the average values of systolic pressure obtained by two nurses using the auscultatory method. The recognition performance was found to be 98.2% for ±20 mmHg, 93.5% for ±15 mmHg, and 82.3% for ±10 mmHg based on the difference between the systolic pressures measured by the auscultation method and the proposed method with a neural network. The collected database for our experiment includes 85 participants with ages ranging from 10–80 years. In this paper, we present a novel personalized traits monitoring system that can monitor personalized traits of systolic blood pressure. This study can serve as a foundation for the diagnosis and management of isolated systolic hypertension.
Induction of L-form Bacteria from Bacillus thuringiensis
Authors: Daulagala PWHKP , Allan EJ
Published: April 2013

Induction of L-form bacteria from Bacillus thuringiensis was investigated with the long-term view of their use as targeted biological control agents within plants. L-forms were successfully induced from B. thuringiensis subspecies israelensis 36-3 by preparing pour plates of exponential cultures in L-phase medium (LPM) containing μg ml-1 cephalosporin C. The induced L-forms were then subcultured and maintained in L-phase medium supplemented with inactivated mycoplasma screened 5% (v/v) horse serum (5HS) with a combination of 225 μg ml-1 cephalosporin C and 0.6 mg ml-1 penicillin G, using the push block method. Induced L-forms showed typical features with pleiomorphic cells that contained granular particles and small vacuoles but no parasporal bodies. These L-forms were capable of growing on solidified media but failed to grow in liquid media. Ceylon Journal of Science (Bio. Sci.) 41 (2): 137-144, 2012 DOI: http://dx.doi.org/10.4038/cjsbs.v41i2.5383
The realities people live by: A critical reflection on the value of Wolfgang Iser’s concept of repertoire for reading the story of Susanna in the Septuagint
Authors: Nolte S. Philip
Published: April 2013

The article investigates the value of Wolfgang Iser’s concept of repertoire for reading the apocryphal story of Susanna. The viewpoint is that fictional literature such as the Susanna narrative and reality are not opposites of each other, but that fictional texts tell us something about reality. The investigation will also include Peter L. Berger’s theory on how religion contributes to construct social reality. The study will show that religious texts construct the reality(ies) in which people interact and try to make sense of everyday existence. Two stories contemporary to the writer of the article are employed to show that in a certain sense male perceptions about women have not changed much over two millennia. The critical engagement with the narrative will also ask how Susanna’s story can be interpreted in a responsible and ethical way that is conducive for the constructive development and transformation of individuals and communities.
An evaluation of security measures implemented to address physical threats to water infrastructure in the state of Mississippi
Authors: Barrett, PhD Candidate Jason R. , French, PhD P. Edward
Published: April 2013

The events of September 11, 2001, increased and intensified domestic preparedness efforts in the United States against terrorism and other threats. The heightened focus on protecting this nation’s critical infrastructure included legislation requiring implementation of extensive new security measures to better defend water supply systems against physical, chemical/ biological, and cyber attacks. In response, municipal officials have implemented numerous safeguards to reduce the vulnerability of these systems to purposeful intrusions including ongoing vulnerability assessments, extensive personnel training, and highly detailed emergency response and communication plans. This study evaluates fiscal year 2010 annual compliance assessments of public water systems with security measures that were implemented by Mississippi’s Department of Health as a response to federal requirements to address these potential terrorist threats to water distribution systems. The results show that 20 percent of the water systems in this state had at least one security violation on their 2010 Capacity Development Assessment, and continued perseverance from local governments is needed to enhance the resiliency and robustness of these systems against physical threats.
Have Maryland local health departments effectively put in place the information technology relevant to emergency preparedness?
Authors: Nguh, PhD, MSN, MHSA, RN Jonas
Published: April 2013

Ever since the terrorist attacks of 9/11, the federal government has increased funding for emergency preparedness. However, the literature continues to document several areas of weaknesses in public health emergency management by local health departments (LHD). This lack of preparedness affects the entire public. The purpose of this study was to determine whether or not Maryland LHDs have effectively put in place the information technology (IT) that is relevant for emergency preparedness. Base Firm-wide IT Infrastructure Services and the Feeny/Willcocks Framework for Core IS Capabilities are the two conceptual frameworks used in this study. This qualitative study used the survey method and the data were analyzed through content analysis. The results revealed that utilization, practice, and performance of IT by Maryland LHDs are not efficient or effective. Recommendations included the development of “best practices,” increased funding for IT infrastructure and the establishment of strategic management framework for IT initiatives. Implications for positive social change include the development of recommendations to enhance emergency preparedness practice, and advancement of knowledge so as to facilitate the functions, and duties of health departments in emergency preparedness operations.
Sequential and joint hydrogeophysical inversion using a field-scale groundwater model with ERT and TDEM data
Authors: Herckenrath D. , Fiandaca G. , Auken E. , Bauer-Gottwein P.
Published: April 2013

Abstract. Increasingly, ground-based and airborne geophysical datasets are used to inform groundwater models. Recent research focuses on establishing coupling relationships between geophysical and groundwater parameters. To fully exploit such information, this paper presents and compares a joint hydrogeophysical inversion (JHI) approach and sequential hydrogeophysical inversion (SHI) approach to inform a field-scale groundwater model with Time Domain Electromagnetic (TDEM) and Electrical Resistivity Tomography (ERT) data. The implemented SHI coupled inverted geophysical models with groundwater parameters, where the strength of the coupling was based on geophysical parameter resolution. To test whether the implemented SHI over- or underestimated the coupling strength between groundwater and geophysical model, we compared its results with a JHI in which a geophysical model is simultaneously inverted with a groundwater model using additional coupling constraints that explicitly account for an established petrophysical relationship and its accuracy. The first set of simulations for a synthetic groundwater model and TDEM data, employing a high-quality petrophysical and geometric relationship, showed improved estimates for groundwater model parameters that were coupled to relative well-resolved geophysical parameters. Compared to a SHI these improvements were insignificant and geophysical parameter estimates became slightly worse. In a second set of simulations, employing a low-quality petrophysical relationship, groundwater parameter improved less for both the SHI and JHI, where the SHI performed slightly better. For a real-world groundwater model and ERT data, different parameter estimates were obtained with a JHI and SHI. Parameter uncertainty was reduced but was similar for the SHI and JHI. The geometric constraint showed little impact while the petrophysical constraint showed significant changes in geophysical and groundwater parameters. For both cases investigated in this paper, the SHI seems favorable, taking in account parameter error, data fit and the complexity of implementing a JHI in combination with its larger computational burden.
Seguridad ciudadana y administración de justicia
Authors: González Sandoval Julio
Published: April 2013

DOI: http://dx.doi.org/10.5377/derecho.v0i8.981 Revista de Derecho No.8 2004 pp.81-88
Autoría mediata, imputación objetiva y autopuestas en peligro
Authors: Roso Cañadillas Raquel
Published: April 2013

DOI: http://dx.doi.org/10.5377/derecho.v0i8.984 Revista de Derecho No.8 2004 pp.113-160
Cuando las normas penales en blanco vulneran el principio de legalidad
Authors: Zúñiga Morales Sandra Eugenia
Published: April 2013

DOI: http://dx.doi.org/10.5377/derecho.v0i8.985 Revista de Derecho No.8 2004 pp.161-182
El fallo del 18 de diciembre de 2003 referente a la solicitud de revisión del fallo del 11 de septiembre de 1992 en el caso de la disputa fronteriza terrestre, insular y marítima (El Salvador Honduras: Nicaragua Interviniendo) (El Salvador vs. Hondura
Authors: Pacheco Blandino Tania
Published: April 2013

DOI: http://dx.doi.org/10.5377/derecho.v0i8.986 Revista de Derecho No.8 2004 pp.183-200
Ne bis in ídem Material y Procesal
Authors: Díaz Miguel , Conlledo García
Published: April 2013

DOI: http://dx.doi.org/10.5377/derecho.v0i9.990 Revista de Derecho No.9 2004 pp.9-27
Análisis de la constitución económica Nicaragüense con especial referencia a la libertad de empresa
Authors: Hererra Espinoza Jesús Jusseth
Published: April 2013

DOI: http://dx.doi.org/10.5377/derecho.v0i9.995 Revista de Derecho No.9 2004 pp.81-104
Tramadol/Paracetamol Fixed-Dose Combination for Chronic Pain Management in Family Practice: A Clinical Review
Authors: Morón Merchante Ignacio , Pergolizzi Joseph V. , van de Laar Mart , Mellinghoff Hans-Ulrich , Nalamachu Srinivas , O'Brien Joanne , Perrot Serge , Raffa Robert B.
Published: April 2013

The family practitioner plays an important role in the prevention, diagnosis, and early management of chronic pain. He/she is generally the first to be consulted, the one most familiar with the patients and their medical history, and is likely the first to be alerted in case of inadequate pain control or safety and tolerability issues. The family practitioner should therefore be at the center of the multidisciplinary team involved in a patient’s pain management. The most frequent indications associated with chronic pain in family practice are of musculoskeletal origin, and the pain is often multimechanistic. Fixed-dose combination analgesics combine compounds with different mechanisms of action; their broader analgesic spectrum and potentially synergistic analgesic efficacy and improved benefit/risk ratio might thus be useful. A pain specialist meeting held in November 2010 agreed that the fixed-dose combination tramadol/paracetamol might be a useful pharmacological option for chronic pain management in family practice. The combination is effective in a variety of pain conditions with generally good tolerability. Particularly in elderly patients, it might be considered as an alternative to conventional analgesics such as NSAIDs, which should be used rarely with caution in this population.
El pluralismo asociativo femenino en municipios españoles. Propuesta de tipología
Authors: Rodríguez García Maria Jesús
Published: April 2013

El objetivo principal de este trabajo es analizar el pluralismo del sectorasociativo femenino en municipios españoles. Más concretamente, sehace una propuesta metodológica para la construcción de una tipologíade asociaciones de mujeres. Se aplica a datos procedentes de unaencuesta realizada en cinco municipios españoles. Los resultadosprincipales confi rman la existencia de pluralismo en este sectorasociativo. Sin embargo, además de los dos tipos principales deasociaciones de mujeres que suele identifi car la literatura (movimientofeminista y asociaciones de mujeres), se identifi can tipos híbridos apartir de su involucración en la co-producción de servicios públicos. Portanto, la co-producción, además de su agenda, su activismo político yla prestación de servicios propios, supone una dimensión relevante paraclasifi car a las asociaciones de mujeres y mejorar el conocimiento sobreeste sector asociativo en España.
Grupos moderados y tolerantes en la polarización política de las redes sociales
Authors: García-Valdecasas Medina José Ignacio
Published: April 2013

Este artículo pretende investigar el tamaño mínimo que debe tener ungrupo de individuos moderados y tolerantes para llevar a una red socialaltamente polarizada e intolerante al consenso político, así comoanalizar el posible efecto de diferentes propiedades estructurales de lasredes (densidad y desigualdad en la distribución de vínculos), y deciertas propiedades individuales (tolerancia y arraigo de las opinionespolíticas) sobre dicho tamaño mínimo. Para ello, se combinan lasimulación basada en agentes y el análisis de redes sociales con objetode realizar experimentos virtuales con redes artifi ciales. Los resultadosrevelan la existencia de un tamaño mínimo crítico por debajo del cual elconsenso político es prácticamente imposible, y ponen de manifi estoque dicho tamaño depende acusadamente de diversas propiedadesestructurales e individuales.
Apnea of Prematurity: Caffeine Dose Optimization
Authors: Francart Suzanne J. , Allen Megan K. , Stegall-Zanation Jennifer
Published: April 2013

OBJECTIVES

The primary objective was to evaluate the correlation between maintenance dose and response rates in neonates less than 28 weeks gestational age. Secondary objectives included clinical indicators of response (number of weight adjustments, dose increases, and mini-loads) and tachycardia associated with caffeine therapy.

METHODS

This study was a retrospective analysis of neonates admitted to the North Carolina Children's Hospital from August 2009 to August 2011. Patients included were less than 28 weeks postmenstrual age and were treated with caffeine for apnea of prematurity. Patients were excluded if they were older than 28 weeks postmenstrual age, receiving caffeine therapy for other indications, or experiencing apnea from other conditions, or if therapy was initiated more than 7 days after birth.

RESULTS

A total of 89 neonates with a mean birth weight of 0.844 kg (range: 0.391 to 1.306 kg) and median gestational age of 26 2/7 weeks (range: 23 to 27 6/7 weeks) were evaluated. The median initial maintenance dose of caffeine citrate was 7.9 mg/kg/day, and 94.1% of neonates receiving ≤7.9 mg/kg/day required a clinical intervention during therapy compared with 76.3% in those receiving >7.9 mg/kg/day. Absolute incidence of tachycardia was low, and caffeine levels collected ranged from 16.6 to 34.4 μg/mL.

CONCLUSIONS

In neonates less than 28 weeks gestational age, doses of caffeine citrate greater than 7.9 mg/kg/day are safe and are associated with a decreased need for clinical interventions.
Ivacaftor: A Novel Gene-Based Therapeutic Approach for Cystic Fibrosis
Authors: Condren Michelle E. , Bradshaw Marquita D.
Published: April 2013

Ivacaftor is a new therapeutic agent that acts at the cystic fibrosis transmembrane conductance regulator (CFTR) channel to alter activity. It is approved for use in patients 6 years and older with cystic fibrosis who have at least 1 G551D mutation in the CFTR gene. It is unlike any other current pharmacologic agent for cystic fibrosis in that it specifically targets the gene defect associated with cystic fibrosis as opposed to treating resulting symptomology. Mucoactive agents, antibiotics, inhaled beta agonists, and other anti-inflammatory agents are currently the mainstay of cystic fibrosis treatment but can be associated with several side effects in addition to cumbersome frequency of administration. Ivacaftor's oral dosing regimen offers a more convenient treatment option. However, it is associated with significant drug-drug interactions.
Blood–Brain Barrier
Authors: Peterson Darryl R
Published: April 2013

The blood–brain barrier consists of endothelial cells lining brain capillaries. It serves to restrict and control the movement of substances between the general circulation and brain extracellular fluid. It participates in regulating the volume and composition of fluid surrounding the brain through specific transport processes, and thus contributes to homoeostasis of the central nervous system. Some of these processes may be regulated hormonally, or modulated by adjacent cells including astrocytes. The barrier function of the blood–brain barrier is due to: (1) tight junctions that restrict movement of substances between the endothelial cells, (2) specific transport proteins that determine which substances can cross the barrier transcellularly and (3) enzymes that may degrade or alter substances prior to passage. Systemically administered drugs intended to treat neurological disorders must be designed to bypass the restrictive elements of the blood–brain barrier. Pathological conditions associated with the central nervous system may alter blood–brain barrier function.

Key Concepts:

The blood–brain barrier regulates brain extracellular fluid.

Brain capillaries form a tight barrier except in specialised areas.

Tight junctions restrict paracellular movement of substances across the blood–brain barrier.

Astrocytes contribute to differentiation of the blood–brain barrier.

Transport across the blood–brain barrier may be passive or active.

Enzymes contribute a metabolic barrier to the blood–brain barrier.

A strategy must be developed to deliver drugs to the brain.

Altered blood–brain barrier function in disease.

Structural and functional properties of the blood–brain barrier.
Cerebellum: Anatomy and Organisation
Authors: Hawkes Richard
Published: April 2013

The cerebellum is a highly stereotyped cortical structure in the hindbrain of all vertebrates from fish to primates. The circuitry of the cerebellar cortex is built around the large, inhibitory Purkinje cells, which are the focus of all afferent input to the cerebellar cortex and are modulated by several classes of inhibitory interneuron (basket, stellate, Golgi and Lugaro cells). Despite the apparent homogeneity of the cerebellar circuitry, the cerebellum is highly modular, comprising several hundred discrete and reproducible anatomical and physiological units (‘stripes’). Each stripe receives precise afferent inputs – climbing fibres directly to the Purkinje cells and mossy fibres indirectly via the granule cells. In turn, the Purkinje cells send efferent projections to specific targets in the cerebellar and vestibular nuclei. As a result, within the cerebellum a wide variety of sensory information is brought together and integrated, primarily to aid in motor control.

Key Concepts:

Cerebellar circuitry is built around the Purkinje cell.

The cerebellar cortex is divided into an array of transverse zones and parasagittal stripes.

The cerebellar cortex receives two major afferent inputs – climbing fibres and mossy fibres.

Purkinje cells are the sole efferent projections of the cerebellar cortex.

Multiple interneurons modulate Purkinje cell firing patterns.
Oestrogen Regulation of Sexual Behaviour, Mood and Cognition
Authors: Almeida Osborne FX , Condé Gillian L , Sousa Nuno
Published: April 2013

Oestrogens are steroid hormones that act through specific receptors in the brain to influence sexual behaviour, as well as mood and cognition. Oestrogen actions include alterations of neuronal excitability, neurotransmitter synthesis and metabolism, neuronal circuitry and neuronal survival, one or all of which may contribute to their effects on mood and cognition. Oestrogens act on a wide variety of peripheral tissues such as breast, bone, liver and heart tissues. Although they have found widespread use for the management of menopausal symptoms, the current consensus is that oestrogen replacement therapy should be used at the lowest possible doses, for a limited duration and with careful consideration of the individual woman's treatment goals and risks. Oestrogens regulate gene transcription, resulting in long‐lasting biochemical changes that can impact adversely on health. The development of improved selective oestrogen receptor modulators that target specific tissues may eventually help circumvent some of the undesired effects of oestrogens.

Key Concepts:

Oestrogens serve important physiological roles in the brain and in peripheral organ systems.

Oestrogens and oestrogen‐like compounds bind to oestrogen receptors; oestrogen receptors occur as two isoforms, known as oestrogen receptor, ERα and ERβ

Oestrogens modulate gene activity, cellular structure and function and ultimately, regulate complex behaviours after binding to specific oestrogen receptors in the brain.

Oestrogen secretion starts during early development, varies cyclically from puberty onwards, and gradually diminishes with age (menopause in women).

Oestrogen‐like compounds that raise health issues are increasingly found in our modern environment as well as in plants; the potency and safety of the latter, especially as dietary supplements, is however questionable.

The therapeutic use of oestrogens in menopausal women should be tailored to an individual woman's needs and should be limited in order to avoid health‐related reductions in quality of life.
Bacterial Ecology
Authors: Fenchel Tom
Published: April 2013

Bacterial ecology is concerned with the interactions between bacteria and their biological and nonbiological environments and with the role of bacteria in biogeochemical element cycling. Many fundamental properties of bacteria are consequences of their small size. Thus, they can efficiently exploit very dilute solutions of organic matter and their potential growth rates are very high. Bacteria do not have a cytoskeleton and they are covered by a rigid cells wall. Therefore they can only take up dissolved low‐molecular‐weight compounds from their surroundings; when bacteria exploit polymeric compounds these must first be undergo extracellular hydrolysis. Bacteria have a great diversity with respect to types of metabolism that far exceeds the metabolic repertoire of eukaryotic organisms. Bacteria play a fundamental role in the biosphere and certain key processes such as, for example, the production and oxidation of methane, nitrate reduction and fixation of atmospheric nitrogen are exclusively carried out by different groups of bacteria. Some bacterial species – ‘extremophiles’ – thrive in extreme environments in which no eukaryotic organisms can survive with respect to temperature, salinity or pH.

Key Concepts:

Fundamental properties of bacteria are related to their small size and lack of cytoskeleton.

Bacteria display a great diversity in types of metabolism.

Bacteria play a key role in the biosphere in terms of transfer of matter and energy.

A number of fundamental biogeochemical processes are carried exclusively by bacteria.

Bacteria play an important role in all types of habitats including some that cannot support eukaryotic life.
Nematophagous Fungi
Authors: Nordbring‐Hertz Birgit , Jansson Hans‐Börje , Tunlid Anders
Published: April 2013

Nematophagous fungi are microfungi that can capture, kill and digest nematodes. They use special mycelial structures, the so‐called traps, or spores to trap vermiform nematodes or hyphal tips to attack nematode eggs and cysts before penetration of the nematode cuticle, invasion and digestion. The more than 200 species known differ in saprophytic/parasitic ability. Although many of the trap‐forming and egg‐parasitic fungi can survive in soil saprophytically, the endoparasites are mostly more dependent on nematodes as nutrients. Molecular data have greatly improved our understanding of the function of the fungi in respect of their taxonomy, their physiological/biochemical activity and their ecology, including their function as biocontrol agents.

Key Concepts:

There are three major groups of nematophagous fungi: the nematode‐trapping fungi that capture free‐living nematodes using specialised morphological structures (i.e. traps), the endoparasitic fungi that infect nematodes using adhesive spores, and the egg‐ and cyst‐parasitic fungi that infect these stages with their hyphal tips.

The nematophagous growth habit has evolved several times and independently since nematophagous fungi are found in all major groups of fungi.

The nematophagous fungi display a large diversity and extensive plasticity of infection structures. In many species, the formation of trapping‐structures is initiated in response to signals from the environment including compounds secreted by the host nematode.

Isolation of more virulent strains, and the development of better formulations and fermentation techniques have significantly improved the efficiency of nematophagous fungi as biological control agents against plant‐ and animal parasitic nematodes.

Nematophagous fungi infect nematodes through a sequence of events including adhesion of the trapping structures to the host nematode surface, followed by penetration, killing and digestion of the nematode tissues.

The secretion of extracellular enzymes such as serine proteases and chitinases are required for successful parasitism of free‐living nematodes and nematode‐eggs by nematophagous fungi.
Viable but Nonculturable Bacteria
Authors: Stokell Joshua R , Steck Todd R
Published: April 2013

Viable but nonculturable (VBNC) bacteria are not detected using standard microbiological assays, hence environmental samples thought to lack bacteria may in fact contain large numbers of these dormant‐like cells. Though regrowth, or resuscitation, of bacteria remains the most definitive measure of the presence of VBNC cells, growth‐independent viability assays using flow cytometry combined with LIVE/DEAD staining, RT‐qPCR and microarray analysis have been developed to detect VBNC cells in environmental samples. Genes specific for the VBNC state have yet to be identified, however, several genes, including
rpoS
, are reported to be involved in the VBNC condition. Further elucidation of the genetic mechanism causing entry into and resuscitation from the VBNC state will likely coincide with advances in transcriptomic and proteomic technologies. Though controversial, the VBNC state can explain certain environmental microbial phenomena, such as the source of recurrent bacterial infections in plants and animals.

Key Concepts:

The VBNC state is thought to be a long‐term survival mechanism that initiates in response to environmental stress.

A general, but not universal, acceptance of the VBNC condition exists even though the molecular mechanism involved has yet to be elucidated.

Resuscitation of the VBNC state has been observed in only some species of bacteria reported to become VBNC.

Several genes, including
rpoS
,
mreB
and
rpf
have been identified as being involved in the VBNC condition.

Bacteria in the VBNC state may retain pathogenicity.
Dengue Fever Viruses
Authors: Whitehorn James
Published: April 2013

Dengue viruses are the most important arboviruses causing disease in humans. Approximately 3 billion people live in areas of risk, and there are an estimated 50–100 million cases occurring each year. These estimates reflect an enormous burden of morbidity, predominantly affecting urban centres of the developing world. There is currently no specific treatment and disease control is limited to tackling the vector. Despite considerable scientific attention disease pathogenesis remains incompletely understood. A better understanding of dengue virus biology and disease pathogenesis has the potential to pave the way to successful therapeutic interventions. This article aims to review current understanding of virus and vector biology, disease pathogenesis and clinical manifestations and management. Finally the article will consider novel approaches to clinical management and disease control.

Key Concepts:

Dengue viruses are the most important arboviruses globally.

Dengue viruses are a significant cause of morbidity, particularly in the tropics.

The pathogenesis of dengue results from both virus and host factors.

Clinical management is limited to parenteral fluids, occasional use of blood products and supportive care.

Despite a long gestation and theoretical safety concerns a dengue vaccine may soon be a reality.

Novel approaches to vector control may aid global disease control efforts.
Enzymes: Irreversible Inhibition
Authors: McDonald Andrew G , Tipton Keith F
Published: April 2013

Many drugs that are in clinical use work by irreversibly inhibiting specific enzymes, either in the individual being treated or in an invading organism. Enzyme inhibitors are also of value for understanding the behaviour of individual enzymes and metabolic systems. Recovery from irreversible inhibition requires the synthesis of new enzyme. Although those irreversible inhibitors that react with specific groups in the enzyme protein generally inhibit more than one enzyme, those that initially form a noncovalent complex with the enzyme, with subsequent reaction within that complex leading to the formation of a covalent bond, can show a high degree of selectivity. Kinetic studies, which are detailed in this account, can be used to distinguish the different types of inhibition and the factors that contribute to effectiveness and selectivity.

Key Concepts:

Irreversible inhibition cannot be reversed by the removal of the excess inhibitor from the system.

Recovery from reversible inhibition depends on the removal of the inhibitor from the system, whereas recovery from irreversible inhibition requires the synthesis of fresh enzyme.

Enzyme turnover in the tissues is a balance between the rate of its synthesis and degradation.

Nonspecific irreversible inhibitors can react with several groups of the same type in different proteins.

Specific irreversible inhibitors form an initial noncovalent complex with the enzyme before the reaction within that complex to form a covalent bond.

Active‐site‐directed inhibitors contain a reactive grouping attached to a substrate analogue.

Mechanism‐based inhibitors can be highly specific because they depend on the activity of the enzyme to form a reactive intermediate that then reacts irreversibly with the enzyme.

Suicide substrates behave as both substrates and irreversible enzyme inhibitors in divergent processes.

Dosage schedule for effective therapy with irreversible inhibitors is dependant on the half‐life of enzyme turnover.
Bromoviridae and Allies
Authors: Scott Simon W
Published: April 2013

The family
Bromoviridae
consists of six genera:
Alfamovirus
,
Anulavirus
,
Bromovirus
,
Cucumovirus
,
Ilarvirus
and
Oleavirus
. All viruses in these genera possess tripartite genomes of single‐stranded, linear, positive‐sense ribonucleic acid (RNA), in which expression of the downstream codon of the RNA3 is via a subgenomic messenger RNA (mRNA) (RNA4).
Raspberry bushy dwarf virus
(RBDV) was the sole member of the genus
Idaeovirus
for many years and shares features in common with members of the genus
Ilarvirus
and
Alfamovirus
, but possesses a bipartite genome and is not currently assigned to a family. Members of the genera
Alfamovirus
,
Bromovirus
and
Cucumovirus
have been used extensively as model systems for research on molecular aspects of plant virology.

Key Concepts:

Although all members of the
Bromoviridae
have similar particle morphologies (quasi‐spherical and bacilliform) and possess tripartite genomes, a range of different strategies is used to express the products of the different genomes.

The phenomenon of genome activation by the coat protein was unique to the ilarviruses and
Alfalfa mosaic virus
but has recently been demonstrated for RBDV.

The natural host ranges of
Cucumber mosaic virus
and
Alfalfa mosaic virus
are extensive whereas many other viruses described in this article have an extremely limited natural host range.

Complete genomic nucleotide sequences are available from GenBank for the majority of viruses referred to in this article.
Plant Viruses with Rod‐Shaped Virions
Authors: Chapman Sean N
Published: April 2013

Plant viruses that form rigid, rod‐shaped particles are found in eight genera. All of these viruses have single‐stranded
ribonucleic acid
(RNA) genomes that, with one exception, are positive‐sense. Most plant viruses with rod‐shaped particles are found in the six genera that form the
Virgaviridae
family with approximately half of all the definitive species in the
Tobamovirus
genus. The virus particles are formed from single structural proteins that encapsidate the genomic RNAs in nonenveloped, helical arrays. Despite their morphological similarities these viruses have diverse molecular and biological properties. While the tobamoviruses have nonsegmented genomes and are mechanically transmitted, the other viruses have segmented genomes and are transmitted by a variety of mechanisms: seed transmission, nematode vectors and plasmodiophorid vectors. Many of the viruses are important disease agents of crop species.

Key Concepts:

Aside from the anomalous
Varicosavirus
genus, all viruses with rod‐shaped virions are single‐stranded, positive‐sense ribonucleic acid (RNA) viruses that replicate in the cytoplasm of host plant cells.

The rod‐shaped virions are formed from helical arrays of a single form of coat protein subunit and their length is dependent on the size of the encapsidated RNAs.

Apart from species within the
Tobamovirus
genus, all viruses with rod‐shaped virions have segmented genomes divided between multiple RNAs.

The plant viruses with rod‐shaped virions use a variety of mechanisms to translate the multiple open reading frames in their genomes, including leaky‐readthrough translation, the use of 3′ coterminal subgenomic RNAs and leaky‐initiation of translation by scanning ribosomes.

The intercellular movement of these viruses within host plants is achieved through the use of a single
Tobacco mosaic virus
‐like movement protein or a ‘triple gene block’ of movement proteins.

The principle mechanism of transmission for all species within a genus varies between genera: the species within four genera are primarily plasmodiophorid transmitted, whereas those in three other genera are primarily mechanically transmitted, seed transmitted or nematode transmitted.

All the genera containing viruses with rod‐shaped virions include species that cause economically important diseases that are controlled through the use of virus‐free seed/vegetative stocks, good sanitary practices and resistant crop cultivars.
Regulation of Neuronal Subtype Identity in the Vertebrate Neural Tube (Neuronal Subtype Identity Regulation)
Authors: Bushati Natascha , Briscoe James
Published: April 2013

The vertebrate nervous system consists of many different neuronal cell types. Each has its own properties, axon projections and connection patterns. This diversity is established early during development and is required for the complex neuronal circuits that characterise the central nervous system. In the spinal cord, a series of events generates different neuronal subtypes, starting with the spatial patterning of neural progenitors. Extrinsic signals provide progenitors in the forming neural tube with positional identity, such that distinct types of progenitors express a unique combination of transcription factors. This transcriptional code determines neural progenitor identity. As progenitors differentiate, they generate distinct neuronal subtypes that are also characterised by a combinatorial transcriptional code. In addition to spatial patterning, other mechanisms contribute to the further diversification of differentiating neurons.

Key Concepts:

Secreted molecules provide positional information to neural progenitors in the developing neural tube.

Progenitors at different positions in the neural tube acquire distinct identities.

The identity of a progenitor is defined by the combination of transcription factors it expresses, which determines the gene expression profile of the progenitor.

An interplay between extrinsic signalling and the downstream gene network produces spatially discrete switches in progenitor identity.

Progenitors with distinct identities differentiate into post‐mitotic neurons with different subtype identities.

The identity of a neuron is determined by the transcriptional code of its progenitor and is itself defined by a separate transcriptional code.

In addition to spatial pattern, temporal changes in progenitor identity and signalling between differentiating cells increases neuronal diversity.
Axon Guidance
Authors: Piper Michael J , Keynes Roger J , Cook Geoffrey MW
Published: April 2013

Axon guidance is the means whereby axon processes growing from differentiating nerve cells are guided to their targets during embryonic development. The growing axon tip, the growth cone, is essential to this process, being capable of locomotion and responding to molecular cues in its cellular environment. A knowledge of the interaction of actin microfilaments and tubulin microtubules of the growth cone cytoskeleton is necessary to understand the dynamic properties of the growth cone. External guidance cues may be attractive or repulsive, and have been shown to fall into diverse molecular families. The signalling pathways that they trigger in the growth cone are being elucidated. Defects in axon guidance may underlie various abnormalities of nervous system development in humans.

Key Concepts:

The growth cone is both a motile and sensory apparatus for axon guidance.

The growth cone cytoskeleton is divided into three regions that mediate distinct aspects of actin–tubulin dynamics.

Regulation of actin assembly and disassembly is important for growth cone locomotion.

Microtubules provide structural support and are responsible for transport of organelles and molecules to and from the growth cone.

Dynamic microtubules are considered to play an instructive role in growth cone turning.

There are two classes of growth cone guidance cue in the cellular environment; attractive/permissive or inhibitory/repulsive. Both classes include members that can act over short distances and members that can act over long distances.

A diverse group of molecular families that mediate guidance has been identified, including members of the immunoglobulin superfamily, cadherins, netrins, Slits, semaphorins and Eph/ephrins.

Growth cone responses to external cues are mediated by molecular signals such as mitogen‐activated protein kinases (MAPK), calcium ions, cyclic nucleotides and the Rho subfamily of small GTPases, which affect cytoskeletal dynamics.