bluuebunny/crossref_metadata_2025 huggingface dataset:
Slowing of growth in height and weight on stimulants: A characteristic pattern
Authors: Poulton A , Cowell CT
Published: October 2010

Objective:  The aims of the present study were to describe the growth pattern of children starting stimulant medication and to analyse the changes over time in height, weight and height velocity in a cohort of treated patients.

Methods:  Retrospective review of growth data from files of all newly treated patients with attention‐deficit/hyperactivity disorder in one paediatric practice. Forty‐four boys and seven girls were treated for 6−42 months with either dexam­phetamine (n = 32) or methylphenidate (n = 19).

Results:  During the first 6 months on stimulant medication 44 children (86%) had a height velocity below the age‐corrected mean and there was weight loss in 39 (76%). The height and weight standard deviation score (SDS) showed a progressive decline that was statistically significant after 6 and 18 months (P < 0.001, paired t‐test). The height velocity was significantly attenuated for the first 30 months (P < 0.01), being lowest during the first 6 months. The mean height deficit during the first 2 years was approximately 1 cm/year. The change in weight SDS was 2.4 times the change in height SDS after 30 months on treatment with a significant correlation (Pearson's correlation coefficient r = 0.88, P < 0.001).

Conclusions:  Stimulant medication is associated with a decrease in height and weight SDS during the first 6−30 months with a characteristic pattern on the growth chart.
Birthweight distribution in southern Chinese infants with symptomatic congenital heart disease
Authors: Jacobs EGJ , Leung MP , Karlberg LJ
Published: October 2010

Objective:  Western infants with congenital heart disease have frequently been reported to have a low birthweight for gestational age. Studies in Asian infants seem to be lacking in this area. This is the first extensive study presenting the birthweight distribution of Chinese newborns with symptomatic congenital heart disease.

Methods:  The birth data of 454, mainly southern‐Chinese infants with symptomatic cardiovascular defects, born between 1990 and 1995 and admitted to Grantham Hospital, Hong Kong in 1994 and 1995, were analysed retrospectively. Infants with (non)‐genetic syndromes or other major extracardiac malformations were excluded.

Results:  Fifteen per cent of all newborns had a birthweight below the reference mean of − 2 Z‐score. After correction for length of gestation, no significant difference could be detected in birthweight between the cyanotic and acyanotic groups, nor between the different haemodynamic disturbances. Infants with atrial or ventricular septal defects, tetralogy of Fallot, pulmonary atresia with ventricular septal defect, heart with univentricular atrio‐ventricular connection or double outlet right ventricle showed significant birthweight deficits. Transposition of the great arteries was not related to being small for gestational age.

Conclusions:  Similar to Western infants, prenatal growth impairment was a common feature in Chinese infants with symptomatic congenital heart disease. The birthweight distribution in Chinese might be comparable to that in Western populations. Exceptions are possibly the high frequency of low birthweight in Chinese newborns with atrial septal defect or a single‐ventricle abnormality. Further studies on fetal anthropometry and haemodynamics are necessary to provide insight into the relation between cardiovascular malformations and being small for gestational age.
Development of psoriatic lesions during acute and convalescent phases of Kawasaki disease
Authors: Zvulunov A , Greenberg D , Cagnano E , Einhorn M
Published: October 2010

Abstract:  A 7‐month‐old infant developed a discrete pustular rash confined to both soles during the acute phase of Kawasaki disease. Histological examination of a pustular lesion from the sole of a foot showed subcorneal neutrophilic microabscesses, psoriasiform acanthosis with a thin granular layer and mononuclear perivascular infiltrates in the upper dermis, consistent with psoriasis. Following the standard treatment with intravenous gamma globulin, the initial symptoms and signs of Kawasaki disease resolved completely. Eight weeks later, psoriasiform plaques appeared on both cheeks and on the extensor surfaces of the forearms and legs. Skin biopsy from one of these lesions revealed psoriasiform epidermal hyperplasia, focal parakeratosis and dilated papillary capillaries. The patient was treated with mild‐potency topical steroids that resulted in rapid and complete resolution of the skin lesions. Concurrent association of psoriatic skin lesions and Kawasaki disease might not be incidental and could stem from a common pathogenetic mechanism induced by superantigens.
Evolving hypopituitarism following cranial irradiation
Authors: Kanumakala S , Warne GL , Zacharin MR
Published: October 2010

Abstract:  Increasing survival after treatment for childhood cancer in recent years has left many patients with long‐term sequelae. Following cranial irradiation, changes in hypothalamic−pituitary function evolve over several years and multiple hormone deficiencies are frequently found. In the present study we describe a boy whose initial presentation with a cerebral tumour included central precocious puberty. He was followed for more than 15 years and sequentially developed deficiencies of growth hormone, thyroid‐stimulating hormone, gonadotrophins and adrenocorticotropic hormone after high‐dose cranial irradiation. Long‐term endocrine follow up of such children is essential for the early diagnosis and optimal management of hormone deficiencies.
Children and war†
Authors: Pearn J
Published: October 2010

Abstract:  Children bear disproportionate consequences of armed conflict. The 21st century continues to see patterns of children enmeshed in international violence between opposing combatant forces, as victims of terrorist warfare, and, perhaps most tragically of all, as victims of civil wars. Innocent children so often are the victims of high‐energy wounding from military ordinance. They sustain high‐energy tissue damage and massive burns − injuries that are not commonly seen in civilian populations. Children have also been deliberately targeted victims in genocidal civil wars in Africa in the past decade, and hundreds of thousands have been killed and maimed in the context of close‐quarter, hand‐to‐hand assaults of great ferocity. Paediatricians serve as uniformed military surgeons and as civilian doctors in both international and civil wars, and have a significant strategic role to play as advocates for the rights and welfare of children in the context of the evolving ‘Laws of War’. One chronic legacy of contemporary warfare is blast injury to children from landmines. Such blasts leave children without feet or lower limbs, with genital injuries, blindness and deafness. This pattern of injury has become one of the post‐civil war syndromes encountered by all intensivists and surgeons serving in four of the world's continents. The continued advocacy for the international ban on the manufacture, commerce and military use of antipersonnel landmines is a part of all paediatricians’ obligation to promote the ethos of the Laws of War. Post‐traumatic stress disorder remains an undertreated legacy of children who have been trapped in the shot and shell of battle as well as those displaced as refugees. An urgent, unfocused and unmet challenge has been the increase in, and plight of, child soldiers themselves. A new class of combatant comprises these children, who also become enmeshed in the triad of anarchic civil war, light‐weight weaponry and drug or alcohol addiction. The International Criminal Court has outlawed as a War Crime, the conscription of children under 15 years of age. Nevertheless, there remain more than 300 000 child soldiers active and enmeshed in psychopathic violence as part of both civil and international warfare. The typical profile of a child soldier is of a boy between the ages of 8 and 18 years, bonded into a group of armed peers, almost always an orphan, drug or alcohol addicted, amoral, merciless, illiterate and dangerous. Paediatricians have much to do to protect such war‐enmeshed children, irrespective of the accident of their place of birth. Only by such vigorous and maintained advocacy can the world's children be better protected from the scourge of future wars.
Effect of postural supports on neuromotor function in very preterm infants to term equivalent age
Authors: Monterosso L , Kristjanson L , Cole J , Evans SF
Published: October 2010

Objective:  To determine the effect of a postural support nappy and/or a postural support roll on neuromotor function in very preterm infants when nursed prone to term equivalent age.

Methods:  A randomized observer blind controlled trial of 123 very preterm infants was conducted in the neonatal intensive care unit of the sole tertiary referral centre in Western Australia. Infants were stratified by gestational age (< 29 weeks or 29−30 weeks), then randomized into one of three intervention groups: postural support nappy, postural support nappy and postural support roll, or disposable nappy and postural support roll. Interventions started when infants were stable and ceased when routine side‐lying commenced. Measurements of shoulder and hip posture were performed pre‐intervention, 5 weeks post‐intervention and term postmenstrual age.

Results:  Infants nursed with a postural support roll and a postural support nappy demonstrated improved hip posture to term equivalent age compared with infants nursed with either a postural support roll only, or a postural support nappy only. Infants nursed with a postural support roll either with or without a postural support nappy demonstrated improved shoulder posture to term equivalent age.

Conclusions:  Combined use of a postural support roll and a postural support nappy while very preterm infants are nursed prone improves hip posture up to term postmenstrual age. Use of a postural support roll improves shoulder posture up to term equivalent age.
Predicting the need for ventilatory support in neonates 30−36 weeks’ gestational age
Authors: Patel H , Beeby PJ , Henderson‐Smart DJ
Published: October 2010

Objectives:  To determine antenatal factors associated with the need for ventilatory support in babies born between 30 and 36 weeks gestational age and use this information to help referring obstetricians decide which mothers need antenatal transfer.

Methods:  Babies born at Royal Prince Alfred Hospital at 30−36 weeks’ gestation inclusive between January 1992 to December 1999 were identified in the obstetric and neonatal databases. Information for a wide range of antenatal factors and respiratory outcomes was extracted. Babies with major congenital anomalies were excluded. Statistical analysis using spss for Windows was then undertaken.

Results:  Data were available for 3102 babies. On univariate analysis, seven factors were significant. Lower gestational age, absence of labour, Caesarean section, antepartum haemorrhage, breech presentation and hypertensive disease of pregnancy were associated with increased risk, while threatened premature labour was protective. On logistic regression analysis, gestational age and absence of labour dominated the model. Other significant factors in the model had a relatively minor impact.

Conclusions:  The risk of needing ventilatory support according to antenatal risk factors is described for infants born between 30 and 36 weeks. Gestational age and absence of labour were found to be the major determinants of risk. Delivery without labour increased the risk by the equivalent of about 2 weeks of gestation. For example, to avoid a risk > 20%, the cut off is 33 weeks for mothers who labour, but is increased to 35 weeks when there is no labour. Our results should be interpreted with caution, as the patients in a tertiary obstetric unit may not be typical of the wider community.
Predicting iron status in low birthweight infants
Authors: Thom R , Parnell W , Broadbent R , Heath A‐L
Published: October 2010

Objective:  To determine the iron status of a selected group of low birthweight infants at approximately 9 months of age, and examine the feasibility of predicting iron status by examining the history of supplementary iron intake.

Methods:  All live low birthweight infants recorded in the Dunedin Hospital Queen Mary Maternity Unit birth register who reached 9 months of age between November 1995 and September 1996 were eligible to participate. Infants were categorized into ‘high’ or ‘low’ iron intake groups depending on their consumption of infant formula or medicinal iron for one month prior to the study, and their iron status compared.

Results:  Eighty‐one infants of 73 mothers, with an average age of 10 months (range 8−13 months), participated. Thirty‐three per cent (n = 27) were iron deficient: 19% (n = 15) had latent iron deficiency and 15% (n = 12) had iron deficiency anaemia. Those with a ‘low’ iron intake were 13‐fold more likely to be iron deficient than infants with a ‘high’ iron intake (95% confidence interval: 4.4−41.5). Screening for iron deficiency using categories based on supplementary iron intake had a positive predictive value of 66% and a negative predictive value of 88%.

Conclusions:  The risk of iron deficiency was considerably greater for infants who had not received supplementary iron daily over the course of the previous month. Current preventative methods for avoiding poor iron status in this group of high risk infants are not effective. Screening for iron deficiency in low birthweight infants on the basis of iron intake from infant formula or medicinal iron provides a useful method for identifying infants whose iron status should be investigated.
Audit of definitive colorectal surgery in patients with early and advanced colorectal cancer
Authors: Isbister William H.
Published: October 2010

Background: The role of surgery in patients with advanced colorectal cancer may be questioned in the era of specialized intensive palliative care. Should patients with advanced disease be advised against surgery because of the risks of the surgery itself? In this study, the perioperative outcomes in patients undergoing definitive surgery for early (Dukes’ stages A, B and C) and advanced colorectal cancer (stage D) were examined.

Methods: All patients undergoing definitive surgery for colorectal cancer during a 15‐year period were identified. Details of tumour site and stage, surgery performed, perioperative complications and postoperative mortality were compared.

Results: A total of 374 patients underwent definitive surgery. There were
193 men, a male : female ratio of 1:0.9. Seventy‐one patients had advanced disease.
There were no differences between the early and advanced groups in perioperative
requirements for either blood or total parenteral nutrition. In the advanced group,
more operations were performed as emergencies than in the early group (32.4 vs
17.5%; P < 0.01) and more patients presented with bowel obstruction
in the advanced group (23.9 vs 10.2%; P < 0.01). There were no site differences between the early and advanced groups and no differences between the operations performed except that endo‐anal destruction was not performed in advanced patients. There were no differences in perioperative morbidity or mortality in the groups studied.

Conclusion: Resection rates, operation type and postoperative morbidity and mortality were similar in patients with both early and advanced colorectal cancers. In terms of perioperative outcome, the presence of advanced cancer, per se, should not, therefore, be a justification to decline surgery.
Aortic aneurysm repair in a peripheral setting: Audit 100 consecutive cases
Authors: Cranshaw Isaac M. , Wilson Nicola C. , Fleischl John M. , Nightingale Michael
Published: October 2010

Background: Subspecialization of vascular surgery and the advent of endovascular techniques for aortic aneurysm repair have had a large impact on the approach to aortic surgery in main centres. Centralization of vascular surgery has been proposed to lower mortality and morbidity rates. More recently, clinical governance standards have been set by professional bodies for acceptable adverse outcome rates in aortic surgery. A peripheral general surgeon’s experience with aortic surgery is reviewed in the present report in order to identify the local adverse outcome rates, and to relate them to case data and governance recommendations.

Methods: A retrospective audit of 100 cases of elective and emergency aortic aneurysm repair (performed by the senior author over a 10‐year period) was undergone for the present review. Demographic and outcome data were recorded, and a data analysis was performed to identify factors related to mortality. Significance was tested using chi‐squared analysis.

Results: Postoperative mortality rates were 1.7% for elective cases and 21% for acute cases. Mortality was related to rupture of the aneurysm, blood loss and American Society of Anesthetists score > 3.

Conclusion: Morbidity and mortality rates from this audit compare favourably with those from larger vascular units. They are well within the accepted clinical governance rates, although the latter do not account for any case mix variation which may exist between peripheral and tertiary referral centres. These results support the continuation of aortic aneurysm surgery in peripheral centres.
Taxonomic and Conservation Status of the Yuma Mountain Lion
Authors: MCIVOR DONALD E. , BISSONETTE JOHN A. , DREW GARY S.
Published: October 2010

Abstract: Confusion persists over the taxonomic status and viability of the Yuma mountain lion (Felis concolor browni). We conducted a review of the literature on lions in the American Southwest and interviewed resource and public‐land managers and wildlife researchers to help us understand the current status of the Yuma mountain lion. We also contacted museums and assembled the most complete set of morphometric data on the Yuma mountain lion. Few if any breeding female lions, a paucity of prey, and a lack of suitable habitat within the reported range of this population cast doubt on its status. We conclude that subspecific status is probably not warranted.

El estado taxoómico y de conservación del león de las Montañas Yuma
Composition of Bird Communities Following Stand‐Replacement Fires in Northern Rocky Mountain (U.S.A.) Conifer Forests
Authors: HUTTO RICHARD L.
Published: October 2010

Abstract:During the two breeding seasons immediately following the numerous and widespread fires of 1988, I estimated bird community composition in each of 34 burned‐forest sites in western Montana and northern Wyoming. I detected an average of 45 species per site and a total of 87 species in the sites combined. A comppilation of these data with bird‐count data from more than 200 additional studies conducted across 15 major vegetation cover types in the northern Rocky Mountain region showed that 15 bird species are generally more abundant in early post‐fire communities than in any other major cover type occurring in the northern Rockies. One bird species (Black‐backed Woodpecker, Picoides arcticus)seems to be nearly restricted in its habitat distribution to standing dead forests created by stand‐replacement fires. Bird communities in recently burned forests are different in composition from those that characterize other Rocky Mountain cover types (including early‐successional clearcuts) primarily because members of three feeding guilds are especially abundant therein: woodpeckers, flycatchers, and seedeaters. Standing, fire‐killed trees provided nest sites for nearly two‐thirds of 31 species that were found nesting in the burned sites. Broken‐top snags and standing dead aspens were used as nest sites for cavity‐nesting species significantly more often than expected on the basis of their relative abundance. Moreover, because nearly all of the broken‐top snags that were used were present before the fire, forest conditions prior to a fire (especially the presence of snags) may be important in determining the suitability of a site to cavity‐nesting birds after a fire. For bird species that were relatively abundant in or relatively restricted to burned forests, stand‐replacement fires may be necessary for long‐term maintenance of their populations. Unfortunately, the current fire policy of public land‐management agencies does not encourage maintenance of stand‐replacement fire regimes, which may be necessary for the creation of conditions needed by the most fire‐dependent bird species. In addition, salvage cutting may reduce the suitability of burned‐forest habitat for birds by removing the most important element—standing, fire‐killed trees–needed for feeding, nesting, or both by the majority of bird species that used burned forests.

Composición de las comunidades de aves luego del reemplazo de rodales a cause de incendios forestales en bosques de coníferas de las montañas Rocosas del norte
Subsistence Hunting in Arabuko‐Sokoke Forest, Kenya, and Its Effects on Mammal Populations
Authors: FITZGIBBON CLARE D. , MOGAKA HEZRON , FANSHAWE JOHN H.
Published: October 2010

Abstract: Mammal populations in Arabuko‐Sokoke Forest, Kenya, provide an important source of protein and income for local communities. The harvested biomass in 1991 was over 350 kg/km2, and the economic value of the harvest was over 1.3 million KShs (approximately US$35,000). Bushpigs, aardvarks, and primates comprise 95% of the harvested biomass, but the main prey in terms of number of animals killed (35% of total) was the four‐toed elephant shrew (Petrodomus tetradactylus). Trapping is concentrated on the periphery of the forest and reduces densities of four‐toed elephant shrews within 1–2 km of the forest edge by 41%, squirrels by 66%, and Syke's monkeys by 55%. Yellow baboons (Papio cynocephalus), Syke's monkeys (Cercopithecus mitis), and the larger ungulates are also hunted with dogs throughout the forest. The results of our study suggest that yellow baboons and Syke's monkeys are overharvested, and current offtake rates of elephant shrews, squirrels, and duikers (Cephalophus spp.) are sustainable. Overharvesting has reduced the densities of large ungulates, including bushbuck (Tragelaphus scriptus) and buffalo (Syncerus caffer), to low levels. Differences in reproductive rates, abundance, population, dispersion, ease of capture, and relative vulnerability to hunting, as compared to trapping, influence the extent to which different prey species are affected by harvesting.

Caza de subsistencia en la selva de Arabuko‐Sokoke, en Kenia, y sus efectos sobra las poblaciones de mamíferos
Fencerows, Edges, and Implications of Changing Connectivity Illustrated by Two Contiguous Ohio Landscapes
Authors: DEMERS MICHAEL N. , SIMPSON JOHN W. , BOERNER RALPH E. J. , SILVA ALEJANDRA , BERNS LESLIE , ARTIGAS FRANCISCO
Published: October 2010

Abstract: We evaluated the amounts and implications of changes in habitat connectivity on rural land‐scapes by modeling the colonization success and subsequent habitat colonization of a model edge organism within real landscapes. We first inventoried the changes in the fencerow and forest‐edge network of two contiguous Ohio (U.S.A.) landscapes, an agriculturally dominated till plain and a more diverse and dynamic moraine landscape, from 1940 to 1988. On the moraine the number of fencerows changed little from 1940 to 1971. The number increased by 86 during 1971–1988 as marginal farms were subdivided. The total length of fencerows on the moraine increased 2.5‐fold over 48 years. On the till plain the number and total length of fencerows remained relatively constant through the study period. The sum of fencerows and forest edges was used as a measure of total ecotonal edge. On the moraine total edge increased through the study period, whereas on the till plain it decreased. We selected two levels of landscape connectivity, low and high, to model animal habitat colonization success. As connectivity increased the earliest successful colonists preempted an increasingly large proportion of the total suitable habitat, and the probability of successful colonization by later‐arriving individuals decreased. The changes in connectivity that resulted from changes in both the fencerow network and the proportion of forested land have resulted in contiguous landscapes that present very different colonization potentials to organisms with long‐distance dispersal capability. Given the current uncertainty of the effects of corridors on species‐preservation efforts, we suggest that further modeling of this type prior to field testing will add useful insights, especially if conducted using specific species and landscape types.

Las cercas, los bordes y las connotaciones de los cambios en la conectividad ilustrados por dos paisajes contiguos de Ohio
Germination and Establishment of the Native Plains Cottonwood (Populus deltoides Marshall subsp. monilifera) and the Exotic Russian‐olive (Elaeagnus angustifolia L.)
Authors: SHAFROTH PATRICK B. , AUBLE GREGOR T. , SCOTT MICHAEL L.
Published: October 2010

Abstract: Russian‐olive (Elaeagnus angustifolia) is a small Eurasian tree that has escaped from cultivation and become naturalized, primarily along watercourses throughout the western United States. We examined germination and establishment of Russian‐olive and plains cottonwood (Populus deltoides), the principal native riparian tree of the Great Plains, under a range of experimental moisture and light conditions. The fewest seedings established under the driest conditions; seedling biomass was predictably lower in the shade; root‐to‐shoot ratios were higher for cottonwood, higher in the sun, and higher under drier conditions. Several interactions were also significant. The timing of germination and mortality varied between plains cottonwood and Russian‐olive: cottonwood germinated in mid‐June in all treatments in a single pulse with subsequent mortality; the timing and amount of Russian‐olive germination differed substantially across treatments with little net mortality. Differences in life‐history traits of these species, including seed size, viability, and dispersal, help explain treatment differences. Russian‐olive will likely remain an important component of riparian communities along both unregulated and regulated western rivers because it succeeds under conditions optimal for cottonwood establishment and under many conditions unfavorable for cottonwood. Furthermore, many western states still encourage planting of Russian‐olive, and control techniques tend to be labor‐intensive and expensive.

Germinación y establecimiento del álamo nativo de las planicies (Populus deltoides Marshall subsp. monolifera) y el olivo ruso exótico (Elaeagnus angustifolia L.)
Potato Diversity in the Andean Center of Crop Domestication
Authors: BRUSH STEPHEN , KESSELI RICK , ORTEGA RAMIRO , CISNEROS PEDRO , ZIMMERER KARL , QUIROS CARLOS
Published: October 2010

Abstract: The diversity and population structure of potato landraces (Solanum spp.) within their center of domestication was studied using isozyme surveys of four polymorphic loci. The objective in assessing the distribution of genetic diversity was to assist in planning conservation strategies of crop genetic resources that are threatened by genetic erosion. In situ conservation methods depend on this type of analysis. Research was conducted in the region of Cusco, Peru. Eight fields spread among two microregions were randomly sampled, and 610 tubers were studied from this sample. In addition, 503 tubers were collected from markets in seven different meso‐regions (provinces) surrounding the regional center of Cusco. Thirty genotypes were identified in the field sample and 82 in the regional sample. The frequency and distribution of genotypes and alleles are described. A high degree of genotype endemism was found at both the field and regional levels. Genotypes were unevenly distributed, and most of the genotypic diversity was between rather than within populations. At the allele level, however, we found that a very high percentage of the diversity was within rather than between populations. The genotype is the key unit for maintaining the population of potato landraces. Our findings suggest that collections need to be both geographically extensive and intensive. Because farmers are able to maintain most alleles on relatively small portions of their land, in situ conservation is a viable strategy.
Ecology of Pacific Yew (Taxus brevifolia) in Western Oregon and Washington
Authors: BUSING RICHARD T. , HALPERN CHARLES B. , SPIES THOMAS A.
Published: October 2010

Abstract: Taxus brevifolia, a subcanopy tree or shrub in forests of the Pacific Northwest, has been harvested intensively in recent years. With management concerns as an impetus, we examined the distribution and population dynamics of Taxus based on data from the mountains of western Oregon and Washington. Surveys of natural forests, long‐term studies of forest recovery following logging, and census data on marked trees in forest stands support the hypothesis that Taxus is a widespread but predominantly late‐successional species. Sensitive to fire and slow to recover from disturbance on many sites, Taxus attains maximal basal area and adult stem density in old forests. Colonization of Taxus is often slow in potentially suitable habitats. Conservation of Taxus at the landscape level may require large, unmanaged reserves and maintenance of patches of old forest within managed forests. Long rotations (centuries) between harvest events will enhance the long‐term viability of the species. Practices designed to accelerate the development of old‐growth forest structure will not benefit Taxus and other species requiring long disturbance‐free intervals for recovery.

Ecologia del tejo del Pacífico (Taxus brevifolia) en el oeste de Oregon y Washington
Effective Population Size and Lifetime Reproductive Success
Authors: ROCKWELL R. F. , BARROWCLOUGH G. F.
Published: October 2010

Abstract: The mean and variance of lifetime reproductive success, ELRS and VLRS, influence the ratio of effective to census population size, Ne/Nc. Because the complete data needed to calculate ELRS and VLRS are seldom available, we provide alternatives for estimating Ne/Nc from incomplete data. These estimates should be useful to conservation biologists trying to compute the effective size of a censused population. An analytical approach makes assumptions regarding the process influencing offspring survival. We provide a method for examining the validity of those assumptions and show that particular violations can result in either over‐ or underestimates. When the assumptions are violated or when more data are available, we suggest estimating Ne/Nc using computer simulations of models based on individuals. We examine how such simulations can be used to estimate Ne/Nc using an individual‐based model for Lesser Snow Geese (Anser caerulescens). We demonstrate that such estimates can be biased unless the simulations are based on complete cohorts and samples of known age. We show that because the estimate of Ne/Nc depends on the stage of the reproductive cycle used as a point of reference in the model, the census population size Nc must be based on the same stage to provide unbiased estimates of Ne.

Tamaño poblacional efectivo y el éxito reproductivo vitalicio
Genetic Structure of Endangered Clapper Rail (Rallus longirostris) Populations in Southern California
Authors: FLEISCHER ROBERT C. , FULLER GARTH , LEDIG DAVID B.
Published: October 2010

Abstract: We assessed the genetic structure of two subspecies of endangered Clapper Rails (Rallus longirostris) in Southern California using DNA fingerprinting to uncover variation in minisatellite DNA. Minisatellite DNA variation in the Salton Sea population of the R. I. yumanensis subspecies was at a level typical of outbred avian species (average proportion of fragments shared, or S, was 0.33). Variation was extremely low (S from 0.63 to 0.77), however, within four coastal, salt‐marsh populations of the subspecies R. I. levipes located along a transect extending about 260 km northwest from the Mexican border. Between‐population similarity (Sij) was also high for the four levipes populations, although individuals of the small, isolated population at Mugu Lagoon consistently clustered separately in phenograms constructed using neighbor‐joining or other algorithms. Individuals of yumanensis always clustered as a sister group to all levipes individuals. The minisatellite data were contrasted with the extremely low mtDNA and RAPD variation we found in both subspecies. We propose that variation in these less‐mutable markers was lost in a bottleneck that occurred at least 1000 years ago, thus allowing sufficient time for recovery of variation in the rapidly mutating (μ∼ 0.001/gamete/generation) minisatellites (t = 1/μ, or 1000 generations). A second, more‐recent bottleneck, or series of bottlenecks within a metapopulation structure, likely resulted in the depauparate variation seen in levipes today. We suggest that translocations from large to small levipes populations could restore important genetic variation to the small populations and would not compromise genetic boundaries.

Estructura genética de las poblaciones de Rallus longirostris en peligro de extinción en el sur de California
Hypoxia Tolerance in Twelve Species of East African Cichlids: Potential for Low Oxygen Refugia in Lake Victoria
Authors: CHAPMAN LAUREN J. , KAUFMAN LESLIE S. , CHAPMAN COLIN A. , MCKENZIE F. ELLIS
Published: October 2010

Abstract: The species flock of haplochromine cichlid fishes in Lake Victoria is one of the most extensive and recent radiations of vertebrates known. Over the past 15 years, however, many of the haplochromine cichlid species have vanished, and predation by the introduced Nile perch (Lates niloticus) is thought to be one of the most significant factors underlying this mass extinction. Information on the hypoxia tolerance of haplochromines from the Lake Victoria is valuable for predicting their response to the increasing anoxia within the lake and in evaluating their potential use of low oxygen regions as refugia from predation by introduced Nile perch. This study examines the response of nine cichlid species from Lake Victoria (eight indigenous, one introduced) and three cichlid species from Lake Tanganyika to different low‐oxygen regimes under laboratory conditions. Fish were exposed to progressive and acute hypoxia, with and without access to the surface. All species used aquatic surface respiration at very low Po2. Buccal bubble holding and active swimming at the surface during aquatic surface respiration were used by many species and may serve to increase its efficiency. Lacustrine cichlids endemic to Lake Victoria were more tolerant of hypoxia than ecologically similar species from Lake Tanganyika. The two species examined that are widespread in variety of aquatic habitats exhibited a relatively high tolerance to hypoxia, with well‐developed aquatic surface respiration and bubble‐holding capabilities and no loss of equilibrium during progressive hypoxia. Species strongly affected by recent changes in Lake Victoria were not consistently poorer in their hypoxia tolerance than less‐affected species. But, two of the less‐affected species are inhabitants of shallow, rocky habitats, an environment that may be both rich in oxygen and well defended against the Nile perch because of the structural complexity of the rocky, littoral area. The generally high levels of hypoxia tolerance in the cichlid species examined from Lake Victoria suggest that these species potentially could use low‐oxygen refugia to escape Nile perch predation. Some species that are thought to have disappeared may currently inhabit low‐oxygen refugia that have not been adequately sampled.

Tolerancia a la hipoxia en cíclidos del Africa oriental: Refugios con bajo contenido de oxígeno en el lago Victoria
Effects of Fishing on the Ecosystem Structure of Coral Reefs
Authors: ROBERTS CALLUM M.
Published: October 2010

Abstract: Overfishing is considered one of the three most significant threats to coral reef ecosystems. Exponentially increasing human populations in the tropics have placed enormous demands upon reefs as a food source. At high intensities, termed ecosystem or Malthusian overfishing, fishing causes major direct and indirect effects on the community structure of fishes and other organisms. It reduces species diversity and leads to local extinctions not only of target species but also of other species not fished directly. Conceivably it could also lead to global extinctions. Loss of keystone species, such as predators of echinoderms, through fishing, can lead to major effects on reef processes, such as accretion of calcium carbonate. Ultimately, sustained heavy fishing may lead to loss of entire functional groups of species, resulting in impairment of the potentially important ecosystem functions provided by those groups. Overfishing has been shown to interact with other agents of disturbance to reduce the ability of reefs to recover from natural occurrences such as hurricanes. Effective management of fishing will require a deeper understanding of the effects of exploitation than we now possess. Research initiatives are underway to examine the responses of fish populations to fishing, generally responses to protection from fishing. There is, however, an urgent need to look beyond fish communities and to consider the entire reef ecosystem. Studies that integrate population and community biology with ecosystem processes will provide a much better understanding of the effects of biodiversity loss on reef function and will improve our ability to manage these complex systems.

Efecto de la pesca sobre la estructura ecosistémica de los arrecifes de coral
Crustal response to continental collisions between the Tibet, Indian, South China and North China Blocks: geochronological constraints from the Songpan‐Garzê Orogenic Belt, western China
Authors: Huang M. , Maas R. , Buick I. S. , Williams I. S.
Published: October 2010

We report SHRIMP U–Th–Pb monazite, conventional U–Pb titanite, Sm–Nd garnet and Rb–Sr muscovite and biotite ages for metamorphic rocks from the Danba Domal Metamorphic Terrane in the eastern Songpan‐Garzê Orogenic Belt (eastern Tibet Plateau). These ages are used to determine the timing of polyphase metamorphic events and the subsequent cooling history. The oldest U–Th–Pb monazite and Sm–Nd garnet ages constrain an early Barrovian metamorphism (M1) in the interval c. 204–190 Ma, coincident with extensive Indosinian granitic magmatism throughout the Songpan‐Garzê Orogenic Belt. A second, higher‐grade sillimanite‐grade metamorphic event (M2), recorded only in the northern part of the Danba terrane, was dated at c. 168–158 Ma by a combination of U–Th–Pb monazite and titanite and Sm–Nd garnet ages. It is suggested that M1 was a thermal event that affected the entire orogenic belt while M2 may represent a local thermal perturbation. Rb–Sr muscovite ages range from c. 138–100 Ma, whereas Rb–Sr biotite ages cluster at c. 34–24 Ma. These ages document regional cooling at rates of c. 2–3 °C Myr−1 following the M1 peak for most of the terrane. However, those parts of the terrane affected by the higher‐temperature M2 event (e.g. the migmatite zone) experienced initially more rapid (c. 8 °C Myr−1) cooling after peak M2 before joining the regional slow cooling path defined by the rest of the terrane at c. 138 Ma. Regional slow cooling between c. 138 and c. 30 Ma is thought to be the result of post‐tectonic isostatic uplift after extensive crustal thickening caused by collision of the South and North China Blocks. The clustering of biotite Rb–Sr ages marks the onset of rapid uplift across the entire terrane commencing at c. 30–20 Ma. This cooling history is shared with many other regions of the Tibet Plateau, suggesting that uplift of the Tibet Plateau (including the Songpan‐Garzê Orogenic Belt) occurred predominantly in the last c. 30 Myr as a response to the continuing northwards collision of India with Eurasia.
Petrological constraints on the formation conditions and retrograde P–T path of the Kotsu eclogite unit, central Shikoku
Authors: Matsumoto M. , Wallis S. , Aoya M. , Enami M. , Kawano J. , Seto Y. , Shimobayashi N.
Published: October 2010

A largely undocumented region of eclogite associated with a thick blueschist unit occurs in the Kotsu area of the Sanbagawa belt. The composition of coexisting garnet and omphacite suggests that the Kotsu eclogite formed at peak temperatures of around 600 °C synchronous with a penetrative deformation (D1). There are local significant differences in oxygen fugacity of the eclogite reflected in mineral chemistries. The peak pressure is constrained to lie between 14 and 25 kbar by microstructural evidence for the stability of paragonite throughout the history recorded by the eclogite, and the composition of omphacite in associated eclogite facies pelitic schist. Application of garnet‐phengite‐omphacite geobarometry gives metamorphic pressures around 20 kbar. Retrograde metamorphism associated with penetrative deformation (D2) is in the greenschist facies. The composition of syn‐D2 amphibole in hematite‐bearing basic schist and the nature of the calcium carbonate phase suggest that the retrograde P–T path was not associated with a significant increase or decrease in the ratio of P–T conditions following the peak of metamorphism. This P–T path contrasts with the open clockwise path derived from eclogite of the Besshi area. The development of distinct P–T paths in different parts of the Sanbagawa belt shows the shape of the P–T path is not primarily controlled by tectonic setting, but by internal factors such as geometry of metamorphic units and exhumation rates.
Fast exhumation of the ultrahigh‐pressure Alpe Arami garnet peridotite (Central Alps, Switzerland): constraints from geospeedometry and thermal modelling
Authors: Olker B. , Altherr R. , Paquin J.
Published: October 2010

Previous studies suggest that the metamorphic evolution of the ultrahigh‐pressure garnet peridotite from Alpe Arami was characterized by rapid subduction to a depth of c. 180 km with partial chemical equilibration at c. 5.9 Gpa/1180 °C and an initial stage of near‐isothermal decompression followed by enhanced cooling. In this study, average cooling rates were constrained by diffusion modelling on retrograde Fe–Mg zonation profiles across garnet porphyroclasts. Considering the effects of temperature, pressure and garnet bulk composition on the Fe–Mg interdiffusion coefficient, cooling rates of 380–1600 °C Myr−1 for the interval from 1180 to 800 °C were obtained. Similar or even higher average cooling rates resulted from thermal modelling, whereby the characteristics of the calculated temperature‐time path depend on the shape and size of the hot peridotite body and the boundary conditions of the cooling process. The very high cooling rates obtained from both geospeedometry and thermal modelling imply extremely fast exhumation rates of c. 15 mm yr−1 or more. These results agree with the range of exhumation rates (16–50 mm yr−1) deduced from geochronological results. It is suggested that the Alpe Arami peridotite passively returned towards the surface as part of a buoyant sliver, caused as a consequence of slab breakoff.
Garnet porphyroblast timing and behaviour during fold evolution: implications from a 3‐D geometric analysis of a hand‐sample scale fold in a schist
Authors: Timms N. E.
Published: October 2010

Detailed 3‐D analysis of inclusion trails in garnet porphyroblasts and matrix foliations preserved around a hand‐sample scale, tight, upright fold has revealed a complex deformation history. The fold, dominated by interlayered quartz–mica schist and quartz‐rich veins, preserves a crenulation cleavage that has a synthetic bulk shear sense to that of the macroscopic fold and transects the axis in mica‐rich layers. Garnet porphyroblasts with asymmetric inclusion trails occur on both limbs of the fold and display two stages of growth shown by textural discontinuities. Garnet porphyroblast cores and rims pre‐date the macroscopic fold and preserve successive foliation inflection/intersection axes (FIAs), which have the same trend but opposing plunges on each limb of the fold, and trend NNE–SSW and NE–SW, respectively. The FIAs are oblique to the main fold, which plunges gently to the WSW. Inclusion trail surfaces in the cores of idioblastic porphyroblasts within mica‐rich layers define an apparent fold with an axis oblique to the macroscopic fold axis by 32°, whereas equivalent surfaces in tabular garnet adjacent to quartz‐rich layers define a tighter apparent fold with an axis oblique to the main fold axis by 17°. This potentially could be explained by garnet porphyroblasts that grew over a pre‐existing gentle fold and did not rotate during fold formation, but is more easily explained by rotation of the porphyroblasts during folding. Tabular porphyroblasts adjacent to quartz‐rich layers rotated more relative to the fold axis than those within mica‐rich layers due to less effective deformation partitioning around the porphyroblasts and through quartz‐rich layers. This work highlights the importance of 3‐D geometry and relative timing relationships in studies of inclusion trails in porphyroblasts and microstructures in the matrix.
Pressure–temperature–time evolution of the Central East Greenland Caledonides: quantitative constraints on crustal thickening and synorogenic extension
Authors: White A. P. , Hodges K. V.
Published: October 2010

Whereas geologists have known for three‐quarters of a century that there was significant crustal thickening in the central East Greenland Caledonides, the crucial role of extensional faulting during Caledonian orogenesis has only been recognized during the past decade. In this paper, new petrographic and thermobarometric observations are presented from migmatitic metasedimentary gneisses of the Forsblad Fjord region (c.72.5°N). Samples of the Krummedal Sequence, collected from the footwall of the upper of two significant splays of the main extensional fault system in the region—the Fjord Region Detachment (FRD)—enable us to establish a relative sequence of metamorphism. Our pressure (P)–temperature (T) results imply a clockwise loop inP–Tspace. As recorded by mineral assemblages in the Krummedal gneisses, prograde metamorphism involved a net increase ofc. 4 kbar and 250 °C, with peak conditions ofc.10.5 kbar at 785 °C. Early burial and heating was followed by near‐isothermal decompression of 4.5 kbar, a process which is attributed to roughly 18 km of tectonostratigraphic throw on the upper splay of the FRD. Combining data reported here with the published data, it is estimated that the approximate tectonostratigraphic throw along the lower splay of the FRD wasc. 16 km.In situU–Th–Pb‐monazite electron microprobe dating suggests that the earliest phase of metamorphism recorded in the Krummedal Sequence gneisses of Forsblad Fjord occurred during the Caledonian orogeny. Furthermore, the combination of our new data with existing conventional TIMS U‐Pb and40Ar/39Ar data imply that: (1) movement along the uppermost splay of the FRD (c.425–423 Ma) occurred at maximum time‐averaged slip‐rates equivalent toc.9 mm of vertical displacement per year; and (2) that the final stages of metamorphism occurred prior toc.411 Ma, although part of this denudation was likely accommodated on overlying extensional structures that may have been active more recently. There is close agreement between our data and results from the Krummedal Sequence north of the field area (72.5°−74°N), and rocks of the Smallefjord Sequence (75°−76°N) that are suggested to correlate with the Krummedal Sequence. This leads us to infer that the events recorded in the Forsblad Fjord region are of orogen‐scale significance.