Rich but morphologically problematic: an integrative approach to taxonomic resolution of the genus Neospirorchis (Trematoda: Schistosomatoidea)

Neospirorchis Price, 1934 is a genus of blood flukes that infect the cardiovascular system, including vessels surrounding the nervous systems of marine turtles. Although the genus comprises just two named species, the available molecular data suggest substantial richness which has not yet been formally described. The lack of description of species of Neospirorchis is probably explained by their small, slender, elongate bodies, which allow them to infect numerous organs and vessels in their hosts, such as the heart and peripheral vessels of nervous system, endocrine organs, thymus, mesenteric vessels, and gastrointestinal submucosa. This morphology and site of infection means that collecting good quality, intact specimens is generally difficult, ultimately hampering the formal description of species. Here we supplement limited morphological samples with multi-locus genetic data to formally describe four new species of Neospirorchis infecting marine turtles from Queensland, Australia and Florida, USA; Neospirorchis goodmanorum n. sp. and Neospirorchis deburonae n. sp. are described from Chelonia mydas, Neospirorchis stacyi n. sp. is described from Caretta caretta, and Neospirorchis chapmanae n. sp. from Ch. mydas and Ca. caretta. The four new species are delineated from each other and the two known species based on the arrangement of the male and female reproductive organs, on the basis of cytochrome c oxidase subunit 1 (cox1), internal transcribed spacer 2 (ITS2), and 28S ribosomal DNA (rDNA) molecular data, site of infection, and host species. Molecular evidence for three further putative, presently undescribable, species is also reported. We propose that this integrated characterisation of species of Neospirorchis, based on careful consideration of host, molecular and key morphological data, offers a valuable solution to the slow rate of descriptions for this important genus. We provide the first known life cycle data for Neospirorchis in Australian waters, from Moreton Bay, Queensland; consistent with reports from the Atlantic, sporocysts were collected from a terebellid polychaete and genetically matched to an unnamed species of Neospirorchis infecting Ch. mydas from Queensland and Florida.

JPEN Journal Club 73. When it is too good to be true

There is an association between low serum levels of vitamin D and susceptibility This article is protected by copyright. All rights reserved.

Pitfalls of Iron Supplementation in Parenteral Nutrition Admixtures for Children with Intestinal Failure

BACKGROUND

Pediatric patients with intestinal failure are at increased risk for iron deficiency. Supplementation is not routinely included in parenteral nutrition solutions. There is currently limited research related to the safety of iron supplementation in parenteral nutrition and for intravenous forms used in patients with intestinal failure. Current ASPEN and ESPGHAN guidelines promote the use of enteral iron, acknowledging the risks of using iron supplementation within parenteral nutrition admixtures.

METHODS

We review a patient case and the current available literature related to iron in parenteral nutrition.

RESULTS

Five major concerns are identified: peroxidation reactions, incompatibility, hypersensitivity, infection risk, and iron overload.

CONCLUSION

We propose an argument against the preferential use of iron supplementation within parenteral nutrition in children with intestinal failure when enteral supplementation or intermittent parenteral infusion may be sufficient.

CLINICAL RELEVANCY STATEMENT

Pediatric patients with intestinal failure are at risk for iron deficiency anemia, anemia due to folate or B12 deficiency, vitamin B6 deficiency, copper deficiency, non-anemic iron deficiency, and anemia of inflammation. Iron status assessment and supplementation for these patients is variable over time. There are several biochemical and physiologic concerns about the safety of adding iron supplementation to parenteral nutrition admixtures. This paper briefly reviews the current available literature. Further research is needed to evaluate best practices for iron supplementation for pediatric patients with intestinal failure. This article is protected by copyright. All rights reserved.

Current practices in lipid emulsion utilization in the prevention and treatment of intestinal failure-associated liver disease: a survey of pediatric intestinal rehabilitation and transplant centers

BACKGROUND

Newer intravenous lipid emulsions (ILEs), such as fish oil-based intravenous lipid emulsions (FO-ILEs) and soybean oil, medium-chain triglycerides, olive oil, and fish oil-based intravenous lipid emulsions (SMOF-ILEs), provide alternatives to soybean oil-based intravenous lipid emulsions (SO-ILEs). We explored current ILE use practice patterns among intestinal rehabilitation and transplant centers.

METHODS

A survey was developed addressing ILE availability, ILE preference in clinical scenarios, and factors influencing ILE choice. This survey was reviewed locally and by the NASPGHAN Intestinal Rehabilitation Special Interest Group, the IRTA scientific committee, and the ASPEN pediatric intestinal failure section research committee. We recruited providers nationally and internationally from centers with and without intestinal transplant programs.

RESULTS

Of 34 complete responses included, 29 respondents were from the US. Center volume varied with 5 centers following <10 patients and 12 centers following >50. Sixteen centers performed intestinal transplants. All centers had access to SMOF-ILEs, 85% had access to FO-ILEs, and 91% had access to SO-ILEs. In new patients, 85% use SMOF-ILEs as the first choice ILE. In those with new intestinal failure-associated liver disease (IFALD), FO-ILE was preferred to SMOF-ILE (56% vs 38%). In those developing IFALD on SMOF-ILE, 65% switch to FO-ILE while 24% remain on SMOF-ILE. Half of respondents reported liver histology to be "Useful but not available" routinely.

CONCLUSIONS

Centers have routine access to alternative ILEs, and these are quickly replacing SO-ILEs in all circumstances. Future work should focus on how this shift in practice affects outcomes to provide decision support in specific clinical scenarios. This article is protected by copyright. All rights reserved.

Effectiveness of Dietary Counselling With or Without Nutritional Supplementation in Hospitalised Patients who are Malnourished or at Risk of Malnutrition - A Systematic Review and Meta-Analysis

Background

Nutrition support is associated with improved survival and nonelective hospital readmission rates among malnourished medical inpatients; however, limited evidence supporting dietary counseling is available. We intend to determine the effect of dietary counseling with or without oral nutrition supplementation (ONS), compared with standard care, on hospitalized adults who are malnourished or at risk of malnutrition.

Methods

We searched MEDLINE/PubMed, CINAHL, Embase, Scopus, The Cochrane Library, and Google Scholar for studies listed from January 1, 2011, to August 31, 2021. Meta‐analysis was performed to obtain pooled risk ratios (RRs) and 95% CIs to estimate the effect. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to assess the certainty of the evidence.

Results

Sixteen studies were identified. Compared with standard care, dietary counseling with or without ONS probably does not reduce inpatient rates of 30‐day mortality (RR = 1.24; 0.60–2.55; I² = 45%; P = 0.56; moderate certainty), slightly reduces 6‐month mortality (RR = 0.83; 0.69–1.00; I² = 16%; P = 0.06; high certainty), reduces complications (RR = 0.85; 0.73–0.98; I² = 0%; P = 0.03; high certainty), and may slightly reduce readmission (RR = 0.83; 0.66–1.03; I² = 55%; P = 0.10; low certainty) but may not reduce length of stay (mean difference: −0.75 days; −1.66‐0.17; I² = 70%; P = 0.11; low certainty). Intervention may result in slight improvements in nutrition status/intake and weight/body mass index (low certainty).

Conclusions

There is an increase in the certainty of evidence regarding the positive impact of dietary counseling on outcomes. Future studies should standardize and provide details/frequencies of counseling methods and ONS adherence to determine dietary counseling effectiveness.

Demographics of Children with Feeding Difficulties from a large Electronic Health Record Database

BACKGROUND

Feeding difficulties are amongst the most common concerns expressed by parents in younger children. However, few studies have reported on the characteristics of patients with clinically significant feeding diagnoses. The aim of the current study is to describe the characteristics of patients diagnosed with feeding difficulties including concurrent conditions, age and gender, sampled nationwide utilizing the Cerner Health Facts® Database (CHFD).

METHODS

We identified patients with a diagnosis of feeding difficulties (ICD9 783.3 or ICD10 R63.3), age 7 months to 17 years, with an outpatient visit between 2010 and 2017. The demographics and complex clinical conditions of this population were categorized. The cohort was then collapsed into a matrix defining recognized phenotype codes for ICD9 and ICD10 diagnoses to identify associated conditions.

RESULTS

We identified 39,674 patients (0.95%) representing 101,684 encounters from 68 health systems across the United States; 43% of patients were female. Gastrointestinal conditions were the most common, followed by malnutrition, developmental and behavioral diagnoses, and neurologic conditions.

CONCLUSIONS

This study is one of the most robust studies defining the prevalence, demographic characteristics and phenotypic profiling of patients with feeding difficulties. In the United States. Our observations have implications on screening and resource allocation to recognize and manage this poorly understood population. This article is protected by copyright. All rights reserved.

Probiotic Treatment Versus Empiric Oral Antibiotics for Managing Dysbiosis in Short Bowel Syndrome: Impact on the Mucosal and Stool Microbiota, Short Chain Fatty Acids and Adaptation

BACKGROUND

Infants and children with short bowel syndrome (SBS) are presumed to be at risk of gut microbial dysbiosis with potential sequelae of bacterial overgrowth that include sepsis, D-lactic acidosis, mucosal inflammation and malabsorption. In neonatal piglets with SBS, we compared intestinal microbial composition, short chain fatty acids (SCFA) and adaptation given probiotic treatment (Lactobacillus and Bifidobacterium spp.) versus oral metronidazole.

METHODS

Following 75% distal small intestinal resection, piglets were allocated to: probiotic (PRO, 500mg BID n=7), metronidazole (MET, 15mg/kg BID n=8) and placebo (PLA, 500mg BID n=8). After 10 days of parenteral and enteral nutrition, 16S rRNA gene amplicon sequencing (colon tissue and stool) were undertaken and SCFA analysis (stool and colon effluent) performed using gas chromatography.

RESULTS

In colon, Shannon diversity was higher for PRO compared to MET and PLA (p=0.002). PRO and PLA increased abundance of Bacteroidetes species (e.g. Bacteroides fragilis), compared to MET (p<0.001). PRO compared to PLA increased abundance of Firmicutes species (e.g. Lactobacillus fermentum) (p<0.001). MET increased abundance of Proteobacteria members, predominately Enterobacteriaceae compared to PRO (p=0.004). In stool, microbial findings were similar and SCFA (butyrate) concentrations were highest for PRO (p=0.003) compared to MET.

CONCLUSION

In pediatric SBS, the empiric use of oral antibiotics, such as metronidazole, is common for presumed clinical consequences of microbial dysbiosis. In this study of SBS piglets, that approach was associated with decreased microbial diversity and increased abundance of potentially inflammatory Proteobacteria. In contrast, a probiotic treatment using Lactobacillus and Bifidobacterium spp. increased both diversity and SCFAs. This article is protected by copyright. All rights reserved.

Life history mediates the association between parasite abundance and geographic features

Though parasites are ubiquitous in marine ecosystems, predicting the abundance of parasites present within marine ecosystems has proven challenging due to the unknown effects of multiple interacting environmental gradients and stressors. Furthermore, parasites often are considered as a uniform group within ecosystems despite their significant diversity. We aim to determine the potential importance of multiple predictors of parasite abundance in coral reef ecosystems, including reef area, island area, human population density, chlorophyll-a, host diversity, coral cover, host abundance, and island isolation. Using a model selection approach within a database of more than 1200 individual fish hosts and their parasites from 11 islands within the Pacific Line Islands archipelago, we reveal that geographic gradients, including island area and island isolation, emerged as the best predictors of parasite abundance. Life history moderated the relationship; parasites with complex life cycles increased in abundance with increasing island isolation, while parasites with direct life cycles decreased with increasing isolation. Direct life cycle parasites increased in abundance with increasing island area, though complex life cycle parasite abundance was not associated with island area. This novel analysis of a unique dataset indicates that parasite abundance in marine systems cannot be predicted precisely without accounting for the independent and interactive effects of each parasite's life history and environmental conditions.

Bolus Gastric Feeds Improve Nutritional Delivery to Mechanically Ventilated Pediatric Medical Patients: Results of the COntinuous vs BOlus (COBO2) Multi-Center Trial

BACKGROUND

Comparison of bolus (BGF) versus continuous gastric feeding (CGF) with respect to timing and delivery of energy and protein in mechanically ventilated pediatric patients has not been investigated. We hypothesized that bolus delivery would shorten time to goal nutrition and increase the percentage of goal feeds delivered.

METHODS

Multi-center, prospective, randomized comparative effectiveness trial conducted in seven Pediatric ICUs (PICUs). Eligibility criteria: 1 month - 12 years of age, intubated within 24 hours of PICU admission, expected duration of ventilation at least 48 hours, eligible to begin enteral nutrition within 48 hours.

EXCLUSION CRITERIA

acute or chronic gastrointestinal pathology, or acute surgery.

RESULTS

We enrolled 158 mechanically ventilated children between October 2015 and April 2018; 147 patients were included in the analysis (BGF = 72, CGF = 75). The BGF group was slightly older than CGF, otherwise the two groups had similar demographic characteristics. There was no difference in the percentage of patients in each group that achieved goal feeds. Time to goal feeds was shorter in the BGF [Hazard Ratio 1.5 (CI 1.02-2.33); P = 0.0387]. Median percentage of target kilocalories [median kcal 0.78 vs 0.59; p = <.0001], and median percentage of protein delivered [median pro 0.77 vs 0.59; p = <.0001] was higher for BGF patients. There was no difference in serial oxygen saturation index between groups.

CONCLUSION

Our study demonstrated shorter time to achieve goal nutrition via BGF compared to CGF in mechanically ventilated pediatric patients. This resulted in increased delivery of target energy and nutrition. Further study is needed in other PICU populations. This article is protected by copyright. All rights reserved.

The Venusian Lower Atmosphere Haze as a Depot for Desiccated Microbial Life: A Proposed Life Cycle for Persistence of the Venusian Aerial Biosphere

We revisit the hypothesis that there is life in the venusian clouds to propose a life cycle that resolves the conundrum of how life can persist aloft for hundreds of millions to billions of years. Most discussions of an aerial biosphere in the venusian atmosphere temperate layers never address whether the life-small microbial-type particles-is free floating or confined to the liquid environment inside cloud droplets. We argue that life must reside inside liquid droplets such that it will be protected from a fatal net loss of liquid to the atmosphere, an unavoidable problem for any free-floating microbial life forms. However, the droplet habitat poses a lifetime limitation: Droplets inexorably grow (over a few months) to large enough sizes that are forced by gravity to settle downward to hotter, uninhabitable layers of the venusian atmosphere. (Droplet fragmentation-which would reduce particle size-does not occur in venusian atmosphere conditions.) We propose for the first time that the only way life can survive indefinitely is with a life cycle that involves microbial life drying out as liquid droplets evaporate during settling, with the small desiccated "spores" halting at, and partially populating, the venusian atmosphere stagnant lower haze layer (33-48 km altitude). We, thus, call the venusian lower haze layer a "depot" for desiccated microbial life. The spores eventually return to the cloud layer by upward diffusion caused by mixing induced by gravity waves, act as cloud condensation nuclei, and rehydrate for a continued life cycle. We also review the challenges for life in the extremely harsh conditions of the venusian atmosphere, refuting the notion that the "habitable" cloud layer has an analogy in any terrestrial environment.

Molecular and Morphological Elucidation of the Life Cycle of the Frog Trematode Langeronia macrocirra (Digenea: Pleurogenidae) in Los Tuxtlas, Veracruz, Mexico

The genus LangeroniaCaballero and Bravo-Hollis, 1949, currently contains 6 species of amphibian trematodes distributed in North and Middle America. The type species of the genus, Langeronia macrocirraCaballero and Bravo-Hollis, 1949, occurs in Mexico and is relatively commonly found as a parasite of leopard frogs. However, information regarding its life cycle is lacking. In this paper, we study the life cycle of L. macrocirra in Laguna Escondida, Los Tuxtlas, Veracruz. Definitive hosts (Rana spp.) as well as potential intermediate hosts (gastropods, bivalves, crustaceans, tadpoles, hemipterans, and odonate naiads) were sampled in the locality and studied to search for the presence of adults and larval stages of the trematode. Specimens were morphologically characterized, and some individuals were sequenced for 1 ribosomal gene (28S rRNA) and 1 mitochondrial gene (COI). DNA sequences of the adults obtained from leopard frogs were matched with those of the larval forms in their intermediate hosts (metacercariae, cercariae, and sporocysts) to demonstrate conspecificity. Further, we conducted a detailed study of the tegument of the body surface with scanning electron microscopy to characterize each of the developmental stages of the life cycle of L. macrocirra.

Unbalanced sex ratios in Germany caused by World War II and their effect on fertility: A life cycle perspective

This paper analyzes the effects of permanently unbalanced sex ratios in Germany caused by World War II on fertility outcomes over the life cycle. Using Census records linked with individual biography data, our analysis confirms the commonly found short-term pattern of decreased fertility rates due to a stark imbalance of the sex ratio. Yet, the long-term effects of such an imbalance crucially depend on when in the life cycle fertility is evaluated. We find that female cohorts with low sex ratios have fewer children at younger ages and a larger fraction remains childless. While childlessness remains higher throughout their life cycle, mothers from affected cohorts catch up and even overcompensate at later ages with respect to the number of children. Our preferred reading of this result is that with low sex ratios women select themselves into late motherhood according to their fertility preferences. This interpretation is consistent with the finding that women from affected cohorts expand their childbearing period and accept lower quality matches in the marriage market. Our findings have important implications for understanding the long-term consequences of large population shocks.

(Digenea, Heterophyidae), Parasitic in the Endemic Snail Aylacostoma chloroticum (Caenogastropoda, Thiaridae) in Argentina

Here we describe a new heterophyid species, Heterophyes yacyretana n. sp., and resolve its life cycle experimentally. We found the prosobranch snail Aylacostoma chloroticum in Candelaria, Province of Misiones, Argentina (a sector of the High Paraná River affected by the Yacyretá Dam), naturally infected with opisthorchioid cercariae. These cercariae lacked pigmented eyespots as well as body pigment and possessed 7 pairs of penetration glands arranged in 2 lateral bands, together with 18 pairs of flame cells and a V-shaped excretory vesicle. We exposed specimens of 21 fish species to emerging cercariae and obtained metacercariae from the muscles of the caudal peduncle of 3 species of siluriform fish, and adults from chicks infected with experimentally obtained metacercariae from the albino variety of the bronce corydoras, Corydoras aeneus. The new species differs from other species in the genus by the number of sclerites on the genital sac, the distribution of the vitelline follicles, and the combination of the size relationship of the suckers and the genital sac with respect to the posterior extent of intestinal ceca. Heterophyes yacyretana is the first species of the genus reported from the Americas.

Life Cycle of the Trout Cecal Nematode, Truttaedacnitis truttae (Nematoda: Cucullanidae): Experimental and Field Observations

Truttaedacnitis truttae is a cucullanid nematode of primarily salmonine fishes. Brown trout (Salmo trutta) in Europe reportedly become parasitized by ingesting lampreys (Lampetra planeri) carrying infective larvae. However, our field and laboratory observations suggested that North American specimens of T. truttae have an alternative life cycle. High abundances and potential impact of T. truttae in rainbow trout, Oncorhynchus mykiss, in the Colorado River drainage in Grand Canyon, where there are no lampreys, prompted a study on the transmission dynamics of this nematode. Eggs of T. truttae, collected from live gravid females, were incubated in the laboratory. Snails, Physa gyrina and Lymnaea sp., were exposed to T. truttae larvae 3-4 wk later. Active larvae of T. truttae were observed penetrating the intestinal wall of exposed snails, and worm larvae were found in the visceral tissues when examined 1 wk after exposure. Larvae in snails showed little growth and development 2 wk later and corresponded to L3 larvae. Infected snails were fed to hatchery-reared juvenile rainbow trout. Developing stages were subsequently found in the mucosal lining and lumen of trout intestines. Adult male and female (gravid) worms were found in the ceca of trout examined 5-6 mo after consuming infected snails. Larvae found in pepsin/trypsin digests and mucosal scrapings from wild, naturally infected, trout corroborate laboratory findings. Screening of Physa sp. and gammarids collected from Colorado River, Grand Canyon, for natural infections with T. truttae using the ITS1 rDNA marker gave positive results. Truttaedacnitis truttae is the second species, after Truttaedacnitis clitellarius of lake sturgeon, capable of using a snail first intermediate/paratenic host and is similar to several other cucullanids in having a histotropic phase of development in the definitive fish host.

Life Cycle of the Trout Cecal Nematode, Truttaedacnitis truttae (Nematoda: Cucullanidae): Experimental and Field Observations

Truttaedacnitis truttae is a cucullanid nematode of primarily salmonine fishes. Brown trout (Salmo trutta) in Europe reportedly become parasitized by ingesting lampreys (Lampetra planeri) carrying infective larvae. However, our field and laboratory observations suggested that North American specimens of T. truttae have an alternative life cycle. High abundances and potential impact of T. truttae in rainbow trout, Oncorhynchus mykiss, in the Colorado River drainage in Grand Canyon, where there are no lampreys, prompted a study on the transmission dynamics of this nematode. Eggs of T. truttae, collected from live gravid females, were incubated in the laboratory. Snails, Physa gyrina and Lymnaea sp., were exposed to T. truttae larvae 3-4 wk later. Active larvae of T. truttae were observed penetrating the intestinal wall of exposed snails, and worm larvae were found in the visceral tissues when examined 1 wk after exposure. Larvae in snails showed little growth and development 2 wk later and corresponded to L3 larvae. Infected snails were fed to hatchery-reared juvenile rainbow trout. Developing stages were subsequently found in the mucosal lining and lumen of trout intestines. Adult male and female (gravid) worms were found in the ceca of trout examined 5-6 mo after consuming infected snails. Larvae found in pepsin/trypsin digests and mucosal scrapings from wild, naturally infected, trout corroborate laboratory findings. Screening of Physa sp. and gammarids collected from Colorado River, Grand Canyon, for natural infections with T. truttae using the ITS1 rDNA marker gave positive results. Truttaedacnitis truttae is the second species, after Truttaedacnitis clitellarius of lake sturgeon, capable of using a snail first intermediate/paratenic host and is similar to several other cucullanids in having a histotropic phase of development in the definitive fish host.

Framework towards more Sustainable Chemical Synthesis Design - A Case Study of Organophosphates

In recent years, the advancement of sustainable chemistry concepts and approaches along with their demonstrated application has become a central part of the design, synthesis, and manufacture of a chemical. Sustainable chemistry not only utilizes the principles of green chemistry, but also expands to incorporate economic, societal, and environmental aspects. This is further elucidated by the incorporation of life cycle assessment/thinking to include the raw material production, manufacture, processing, and use and disposal stages, allowing for a comprehensive evaluation of the environmental and human health impacts attributed to a chemical. This contribution outlines an approach for the development of a preliminary framework for the sustainable synthesis of a chemical that is identified as an alternative for an existing chemical of concern. The framework is introduced concurrently with a case study for organophosphates that are selected as potential replacements for brominated flame retardants (BFRs). This framework is designed to apply existing knowledge of green chemistry to the synthesis of alternatives, along with its integration into Life Cycle Assessment culminating in the development of a more overall sustainable chemical entity when compared to its predecessor.

Klossiella equi Infecting Kidneys of Ontario Horses: Life Cycle Features and Multilocus Sequence-Based Genotyping Confirm the Genus Klossiella Belongs In the Adeleorina (Apicomplexa: Coccidia)

Species in the genus Klossiella Smith and Johnson, 1902 are unique among the suborder Adeleorina because they are monoxenous in mammals exclusively, whereas all other reported members of the Adeleorina use invertebrates as definitive hosts. Unlike other coccidia, all members of the Adeleorina undergo syzygy, the association of microgamonts and macrogamonts before maturation to gametes and syngamy. After fertilization, many members of the Adeleorina produce thin-walled polysporocystic oocysts. Despite being biologically similar to other members of the Adeleorina, the phylogenetic placement of the genus Klossiella has been questioned based on its unique host affinity. In the present study, 2 cases of Klossiella equi were reported from the kidneys of horses in Ontario. Details of the life cycle as well as mitochondrial and nuclear 18S ribosomal DNA ( 18S rDNA) sequences were analyzed to provide both morphological and molecular evidence for the phylogenetic placement of K. equi. Initially, various stages of the life cycle were identified in histological slides prepared from the kidney tissue, and DNA was isolated from the infected tissue. Polymerase chain reaction and Sanger sequencing were used to generate a complete mitochondrial genome sequence (6,569 bp) and a partial 18S rDNA sequence (1,443 bp). The K. equi 18S rDNA sequence was aligned with various publicly available apicomplexan 18S rDNA sequences. This alignment was used to generate a phylogenetic tree based on Bayesian inference. Multiple K. equi stages were identified including meronts, microgamonts, and macrogamonts associating in syzygy as well as thin-walled oocysts in various stages of sporogonic development. The 18S rDNA sequence of K. equi positioned within the monophyletic Adeleorina clade. The mitochondrial genome of K. equi contained 3 coding sequences for cytochrome c oxidase I, cytochrome c oxidase III, and cytochrome b as well as various fragmented ribosomal sequences. These components were arranged in a unique order that has not been observed in other apicomplexan mitochondrial genomes sequenced to date. Overall, it was concluded that there were sufficient morphological and molecular data to confirm the placement of K. equi and the genus Klossiella among the Adeleorina. The biological and molecular data obtained from these cases may assist with future studies evaluating the prevalence and life history of this seemingly underreported parasite and better define the impact of K. equi on the health of domestic and wild equids.

The Life Cycle of Engineered Nanoparticles

The first years in the twenty-first century have meant the inclusion of nanotechnology in most industrial sectors, from very specific sensors to construction materials. The increasing use of nanomaterials in consumer products has raised concerns about their potential risks for workers, consumers and the environment. In a comprehensive risk assessment or life cycle assessment, a life cycle schema is the starting point necessary to build up the exposure scenarios and study the processes and mechanisms driving to safety concerns. This book chapter describes the processes that usually occur at all the stages of the life cycle of the nano-enabled product, from the nanomaterial synthesis to the end-of-life of the products. Furthermore, release studies reported in literature related to these processes are briefly discussed.

[New perspectives in life-event history analysis]

"In the last decade, life-event history analysis, also called failure time data analysis or survival analysis, has been widely adopted by demographers. This methodology in demography allows [us] to overcome major hurdles especially when analyzing longitudinal survey data. This paper describes the new perspectives opened to research in that field, and is illustrated by new results and examples of research projects. The authors concentrate on four issues: the analysis of incorrect and imperfect data, the analysis based on more complex data and lastly the study of interaction between phenomena." (SUMMARY IN ENG AND SPA)

Biological aspects of menopause: across the lifespan

"This review outlines the biological basics of menopause and then places menopause within the context of a dynamic lifespan. The basic tenets of the lifespan approach maintain that, for each individual, aging and development are lifelong processes from birth to death; biological, psychological, and sociocultural trajectories interweave across the life course; the entire lifespan serves as a frame of reference for understanding particular events or transitions; and the life course can be affected by environmental change.... This review also points to the gap between population-level studies of menopause and studies carried out at the biochemical, cellular, or organ systems level. Filling this gap...offers the most interesting directions for future anthropological research."

The event history approach in demography

"In the present paper, we shall examine...changes in the field of demography, by following the progression from period analysis to cohort analysis. We shall discuss the hypotheses underlying each of these approaches and show how their distance from actual human behaviour could lead to mistaken or incomplete conclusions. We shall then show how event history analysis can solve these problems and we shall define the hypotheses implied by this new approach. Finally, we shall come back to the complimentarity of the different social sciences."

Counterurbanization: spatial division of labour and regional life-cycles in Canada

"After a discussion of major concepts of counterurbanization, a narrow definition is proposed. Various demographic and socio-economic dimensions are analysed at different scales with special regard to the Canadian heartland. The basic hypothesis suggests a temporary weakening of urban growth dynamics: decentralization, thus, is a result of locational adjustment strategies, emerging during revolutions in basic technology. The corresponding 'filtering down' processes create a selective, interregional spread of labour. However, shift analytical time series indicate that the development capacity of core regions oscillates in a life-cyclical rhythm. Counterurbanization is expected to fade out with regional adjustment to basic technological transformation."

Migration and the family: the female perspective

"This article shows that a family perspective is especially important for the analysis of female migration because: (1) women are major participants in 'family migration' as defined by governments and, although they benefit from family reunification provisions, they are also constrained by them; (2) migrant women are important economic actors and their participation in economic activity is closely related to the needs of their families, so that the choices that migrant women make regarding work cannot be understood without taking into account the situation of their families and women's roles within them; (3) women are increasingly becoming migrant workers in order to improve the economic status of their families; and (4) women rely on their families to provide various types of support that both make migration possible and condition its outcome. A review of the literature provides evidence supporting each of these observations."

Time, age, and the transition to retirement: new evidence on life-course flexibility?

The past twenty-five years have been dramatic changes in the transition to retirement. This article considers an overlooked set of social processes--informal age structuring--within the context of these changes. Data are drawn from a random sample of 319 adults from the Chicago area. For about half of the respondents, age was considered an irrelevant dimension for both men's and women's retirement. Those respondents who found age relevant cited deadlines that were clustered not only around the critical points at which researchers have observed regularity in retirement patterns, but they also included the lower junctures that are emerging as part of the shift toward earlier retirement. These deadlines most often marked the place of retirement relative to a larger set of work transitions, or they budgeted enough time to pursue developmental opportunities at the end of life. However, most respondents said there were no serious consequences for retiring late. Important patterns also emerged across the background characteristics of our respondents. These findings feed into several provocative debates that relate time and age to models of life-course flexibility or rigidity.

Things ain't what they used to be! Demography, mental cohorts, morality and values in post-war Australia

This is the "presidential address to the Ninth Biennial Conference of the Australian Population Association, Brisbane, 30 September 1998.... I propose to look back 50 or so years, at a period of demographic change in Australia that I have found intensely interesting, and that it is hard to imagine will be rivalled in extent or profoundness over the next half century." Aspects considered include morality and values--demographic evidence of change; broad changes in nuptiality and fertility; the sexual revolution; contraception; and life cycle changes.

Transition to adulthood of female garment-factory workers in Bangladesh

This article examines data from a study on garment-factory workers in Bangladesh to explore the implications of work for the early socialization of young women. For the first time, large numbers of young Bangladeshi women are being given an alternative to lives in which they move directly from childhood to adulthood through early marriage and childbearing. Employment creates a period of transition in contrast to the abrupt assumption of adult roles at very young ages that marriage and childbearing mandate. This longer transition creates a period of adolescence for young women working in the garment sector that is shown to have strong implications for the women's long-term reproductive health.

The menopausal experiences of women in a developing country: "there is a time for everything: to be a teenager, a mother and a granny"

The menopausal experiences of 26 Zimbabwean women were explored, using a structured open-ended interview schedule. Interviews were carried out in Harare in 1995. An analysis of the consensual data indicated that these women do experience the menopause symptoms that have been claimed elsewhere to be universal. Their experiences of menopause were not, however, regarded generally as distressing and were interpreted as a normal stage in the life cycle. Particular cultural beliefs are described which impact on women's understandings and reactions to the menopause.

Fertility in The Netherlands as an expected value process and developmental readiness

In this 2-wave panel study, the decision to have children was examined in the context of Feather's (1982) expectancy-value model among a representative sample of 288 childless Dutch adults aged 18-30 years. The effects of 2 indicators of developmental readiness (age and duration of relationship) were also explored. It was expected that (a) the likelihood of having a baby would increase as a function of intentions, evaluations of being childless, and expected rewards of having children and (b) developmental readiness would be positively related to whether respondents had children at the 2nd wave of the study. Structural equation modeling was used. The results largely supported expectations. Developmental readiness affected fertility both directly and indirectly via the expected rewards of having children.

Migration and the life course: is there a retirement transition?

"This paper focuses on pre-elderly (ages 55-64) net migration in the United States for the period 1980-90, to explore the hypothesis that there exists a ¿retirement transition' that characterizes pre-elderly migration.... This research uses ordinary least squares regression to compare the effects of demographic, economic, and amenity factors on county-level net migration rates for five age groups: the young (25-44), the middle-aged (45-54), the pre-elderly (55-64), the young-old (65-74), and the old-old (75+). Pre-elderly migration patterns emerge as distinct from those of both younger and older age groups. Their net migration patterns are not fully shaped by labour force considerations. At the same time, pre-elderly migration appears to be driven by factors beyond retirement. These findings are discussed in the context of life-course change and their implications for the ageing baby-boom cohorts [considered]."

Spatial chain patterns of intra-urban migration

"This research analyzes quantitatively the track of individual chain-type migration of many residents to determine how they move in response to changes in their lives, i.e., whether there is spatial regularity on the chain patterns of intra-urban migration. The study area for this research is the industrial city of Yokkaichi, Japan. The study helps us to understand the state of intra-urban migration at the non-aggregate level for all residents during a 15-year period. Special attention is given to the age at which a resident relocates, and to the interval between two successive movements, i.e., the stationary period."

Analysis of completed parity using microsimulation modeling

"This paper aims to construct a demographic microsimulation model, which is easily applicable to gene transmission..., and to examine the distribution of completed parity as a fertility measure at a population level according to the schedule of individual life course....The simulation model was applied to the data of the Gidra-speaking people living in the lowlands of Papua New Guinea."

Are young people leaving home earlier or later?

"Although the popular view is that young people are leaving home later, a closer investigation of [Australian] data from 1979 to 1995 shows that this is not entirely true. Decreases are observed in the proportion of 15-19 year old men and women living at home at least since the mid-1980s, the increase for 20-24 year old men ceased in 1990, and only 20-24 year old women show a sustained increase. If only unattached young adults are considered instead of the conventional measure, any increases are even more subdued. The overall trend seems to be that while late leavers may be leaving home later, early leavers are leaving earlier or at the same time."

[Internal migration in Italy: an overview of studies in the early 1990s]

The author examines "the content of the studies mentioned in the bibliography in order to [investigate]...both the most recent general tendencies of short and long distance migrations [in Italy]. Economic variables appear to have lost a good deal of their explanatory capacity on behalf of causal factors linked with the ¿life cycle'. Also mentioned are the main conceptual categories used in order to define the consequences of migrations on the spatial distribution of populations: so-called ¿atomistic' settlement models, based on administrative units, are now in competition with the growing importance of ¿functional' models, based on pull areas." (SUMMARY IN ENG AND FRE)

Socio-economic differences in mortality. A life course approach

"Differential mortality in Norway has been studied on the basis of a sample of data derived from the linkage of the 1960, 1970, and 1980 censuses to vital registration records. Based on the hypothesis that the determinants of survival act in interaction, two models are proposed. The first is based on states defined at each observation period by the conjunction of attributes characterizing each individual. The second model considers the chronological order of the states. Logistic regression applied to the latter shows that the most favourable male and female life trajectories are those for married people belonging to rather privileged categories. There are however some differences by sex, as favourable trajectories concern both economically inactive females and employees." (SUMMARY IN FRE)

The changing meaning of cohabitation and marriage

"In the Netherlands, the social meaning of both marriage and cohabitation has changed. Cohabitation started as an alternative way of living, developed into a temporary phase before marriage, and finally became a strategy for moving into a union gradually.... This article addresses the question whether or not individual past and current life-course experiences become increasingly important in explaining the differentiation of entry into marriage across female birth cohorts, and yet become decreasingly important in explaining the differentiation of entry into cohabitation across female birth cohorts. This question is examined using a non-proportional hazard model. Empirical evidence supports this hypothesis strongly, in that both past determinants such as family size or religion and current life-course determinants such as work or education change in their impact on cohabitation and marriage across birth cohorts."

Understanding educational sequences and their consequences on the timing of marriage

"This study examines educational sequences and their consequences on the timing of marriage using the life history data from the 1983 Korean National Migration Survey....I find that the educational process in Korea becomes stabilized and institutionalized during middle and high schooling as middle and high school education becomes a mass experience. However, both men and women are likely to undergo a disorderly sequence during the transition period from high school to college due to the very fierce college entrance examination. Men are also likely to experience a disorderly sequence before or after military service. Both men and women who experience an interruption in their schooling after graduation from high school have lesser odds of getting married than those who keep their educational process orderly."

Populations with constant immigration

"We consider a Leslie-type model of a one-sex (female) population of natives with constant immigration. The fertility and mortality schedule of the natives may be below or above replacement level. Immigrants retain their fertility and mortality, their children adopt the fertility and mortality of the natives. It is shown how this model may be written in a homogeneous form (without additive term) with a Leslie-type matrix. Reproductive values of individuals in each age group are discussed in terms of a left eigenvector of this matrix. The homogeneous form of our projection model permits the transformation into a Markov chain with transient and recurrent states. The Markov chain is the basis for the definition of genealogies, which incorporate immigration. It is shown that genealogies describe the life histories of individuals in a population with immigration. We calculate absorption times of the Markov chain and relate them to genealogies. This extends the theory originally designed for closed populations to populations with immigration." (SUMMARY IN FRE)

A survey report on the life cycle of the Chinese elderly

"In August 1992...the Chinese-Japanese Survey Group on the Life Cycle of the Elderly conducted a sample survey on the life experience and status quo of the elderly in Zhejiang Province and the City of Shanghai, which covered 1,583 urban and rural elderly at or above the age of 60....[The aim was to] not only help change the attitudes towards reproduction among women at child-bearing age, but also contribute to a well-drafted development program for the elderly care system in China so as to prepare the country for the situation after the 2020s when the parents of only children become senior citizens."