bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect on ewe and lamb performance of feeding twin-bearing hill ewes adequately in late pregnancy
Authors: M. H. Davies
Published: June 2019

Real-time ultrasonic scanning of pregnant ewes has become popular, and offers many potential advantages in flocks lambing at 110-170%. This experiment was set up to quantify the beneficial effect on sheep performance that can be obtained, from correct late pregnancy feeding of outwintered, twin-bearing hill ewes.

A hill flock numbering 369 Scottish Blackface ewes in regular ages were pregnancy scanned in mid-February 1985 and 1986 (45-92 days post-conception). From the identified twin-bearing ewes, 102 ewes in 1985 and 166 ewes in 1986 were randomised into two groups in early March, six weeks before lambing was due to commence.
Genetic relationships between growth and food intake in performance tested ram lambs
Authors: Cameron N.D.
Published: June 2019

Efficient lean growth may, in future, be the main selection objective in terminal sire breeds of sheep. The genetic relationships between growth rate, food intake and food conversion ratio need to be quantified, so that calculation of selection indices for growth rate and carcass lean content can take account of correlated changes in food intake.
Control of Reproduction in Seasonally Breeding Ruminants
Authors: Lincoln G.A.
Published: June 2019

All species of ruminants which have evolved in cold or temperate climates are seasonal breeders. This includes many species which have been domesticated such as sheep, goats, cattle, deer and camels. In the wild, births usually occur in spring or summer at a time of year optimal to survival of the offspring; this means that the period of fertility is restricted to a short mating or rutting season. The environmental factors which ultimately dictate the birth season (eg temperature and food supply) are different from the factors which act as proximate cues to dictate the time of the mating season (eg day-length).

In all seasonal breeders, the seasonal cycle In fertility is driven by changes in the pulsatile secretion of LHRH from the brain which dictates the level of release of LH and FSH from the anterior pituitary gland and the consequent activity of the ovaries or testes. Steroid hormones from the gonads act on the numerous target tissues including the brain where they modulate the LHRH pulse-generator and influence sexual and aggressive behaviour.
The effect of melatonin on the peripheral concentrations of LH and progesterone post-oestrus and on conception rate in ewes
Authors: Wallace J.H. , Robinson J.J. , Wigzell S. , Aitken R.P.
Published: June 2019

Previous studies have shown that for Scottish Blackface ewes kept under a natural photoperiod and exposed to the ram the daily administration of the indoleamine melatonin from June onwards advanced the breeding season and appeared to increase ovulation rate and subsequent litter size (Wigzell et al., 1986). In the primate, exposure to melatonin has been shown to stimulate progesterone production by the corpus luteum in an in vivo perfusion system (Webley & Hearn, 1987). Similarly melatonin administered at physiological concentrations stimulated progesterone production by bovine and human granulosa cell cultures (Webley & Luck, 1986).

The present experiments were carried out to determine:-

(a) whether or not melatonin enhances progesterone production and thereby the establishment of pregnancy and embryo survival in the ewe.

(b) whether melatonin acts directly on the corpus luteum or indirectly via increased activity of the hypothalamic GnRH pulse generator.

(c) whether or not the presence of the ram in the immediate post-oestrus period alters the endocrine status of the ewe and thereby influences conception.
The effect of roughage quality on intake, digestion and rumen function in sheep
Authors: Hovell F.D.DeB. , Masvaure S.M. , Gregory P.C. , Kyle D.J.
Published: June 2019

In a previous experiment (Hovell et al. (1987)) it was found that with two roughages, one of good (hay) and the other of poor (straw) degradability, both ground and pelleted, that the voluntary intake of the hay was (60% greater than that of the straw. This was despite the fact that rumen DM pool sizes were very similar. The outflow of undegraded material from the rumen was much greater with the hay although particle size should not have been a constraint to outflow with either roughage (Poppi et al. (1980)), and indeed their particle size distributions were very similar. It was suggested that there might have been an effect of roughage quality on rumen outflow rate, possibly mediated through an effect on reticulo-rumen contractions.

The objective of the experiment reported here was to examine the effect of roughages with different degradabilities on voluntary intake, rumen volume, rumen outflow rate, and on reticulo-ruminal contractions.
Appraisal of the York Electronics egg quality testing equipment when used by several operators
Authors: Hoste S. , Bedford T. , Walker H. , Butler E. A.
Published: June 2019

This equipment records egg weight (g) shell colour (% reflectance) shell weight (g) and thick albumen height (measured on an egg broken out onto a flat plane), and through the connection with a dedicated microprocessor derives the Haugh units (a logarithmically transformed measure of albumen height) and shell weight per unit surface area (mg/cm2). Means, standard deviations and coefficients of variation for a batch are transferred to a printer and/or microprocessor.

Experiment 1

Three operators each made three sequential measurements of egg weight and shell colour on 31 eggs, each record being automatically captured by the microprocessor.

Experiment 2

Using the same procedure four operators made two sequential measurements of egg weight, shell colour and albumen height on 30 eggs.
Effect of Cellulase Enzymes on Degradation Characteristics of Ensiled Rice Straw
Authors: Nakashima Y. , Ørskov E.R. , Ambo K. , Takase Y.
Published: June 2019

Rice straw was ensiled in laboratory containers of 11 capacity. Three concentrations of moisture (50, 60 or 70%) 3 concentrations of a commercial cellulase enzyme preparation (0, 5 or 10g/kg dry matter (DM)) and 3 types of straw processing (2 cm, 5 mm or 2 mm length) were used. The preparations were stored at room temperature (approximately 20°C) for 30 days. The straw treated with cellulase had a lower final pH (5.21, 4.87, 4.82; P<0.05), higher concentrations of lactic acid (198, 383, 367 mg/100g; P<0.05), a lower content of neutral detergent fibre (689, 630, 620 g/kg DM; P<0.05) and a higher solubility, measured as washing losses from nylon bags (152, 196, 212 g/kg DM; P<0.05) for the 0, 5 and 10 g/kg cellulase treatments respectively. The samples were subsequently incubated in nylon bags in the rumen of 3 sheep for 8, 16, 24, 48 and 72 h to estimate degradation rate and potential degradability using the expression p+a+b(1-e-ct) where p is degradability at time t and a, b and c are constants. While there was no effect of moisture content or physical form of the straw, the degradation rate constant (c) was significantly increased (P<0.05) by the addition of cellulase. The maximum potential (a+b) however was unchanged. The values for c were 0.0496, 0.0677 and 0.0847/h-1 and the values for (a+b) were 624, 621 and 628 g/kg for the 0, 5 and 10 g/kg cellulase enzyme additions respectively. It is concluded that the use of cellulase enzymes can assist in the preservation of wet straw and can result in improved degradation characteristics.
The effect of increasing sward surface height in mid-season on performance of grazing ewes and lambs
Authors: Mackie C K , Keeling B J , King M E , Wilkinson S C , Weatherill G
Published: June 2019

Higher lamb growth rates have been observed on swards that increased in height over time than on swards of constant or decreasing height (Doney et al, 1987; Lloyd et al, 1987). Where ewes and lambs were maintained at sward surface heights (SSH) within the ranges 4-6 cm or 6-8 cm until weaning in August, high rates of lamb growth were achieved until the end of June whereafter there was a marked decline (Keeling et al, 1987). The present study investigated the effect on lamb performance of increasing sward height at the end of June.

One hundred and fifty Mule ewes with Suffolk cross lambs were grazed on an area of permanent grass (89% perennial ryegrass) which received 255 kg N/ha over the season in 4 dressings with balancing P and K. The initial stocking rate was 19 ewes and 31 lambs/ha and SSH was maintained in the range 4-6 cm from May 6 until the end of June.
Relationship Between Body Fat Reserves and Body Condition Score in Sheep at Different Physiological Stages
Authors: Castrillo C. , Baucells M. , Guada J.A. , Purroy A. , Sebastian I.
Published: June 2019

Body condition score has been shown to be highly correlated to the degree of body fatness in slaughtering experiments involving a pre-established range of body condition score in sheep at the same physiological stage,but there is a lack of evidence in animals at different physiological conditions. The aim of the present work was to evaluate the usefulness of subjectively assessed body condition score to predict the proportion of chemical fat in the body of Romanov x Rasa ewes at different stages of their reproductive cycle. An adaptation of Russel et al.(1969) condition scoring system was used in wich animals were scored on a 0 to 5 scale to the nearest 0.25 condition unit.
A Comparison of the Effectiveness of Different Methods of Eliminating Cobalt Deficiency in Grazing Sheep
Authors: Paterson Jessie E. , MacPherson Allan , Klessa David
Published: June 2019

Upland pasture improvement can induce sub-clinical cobalt deficiency in grazing animals, leading to lowered productivity. A trial was set up to investigate three methods of combating this problem, namely: monthly vitamin B12 injections, administration of a slow-release bolus at the start of the grazing season and treatment of the pasture with cobalt sulphate.

A recently improved permanent grassland of 5 ha was split in two and one half treated with cobalt sulphate at 2 kg/ha. During two summers, 15 Blackface ewes with twin lambs grazed each pasture. One lamb from each pair on the untreated pasture was treated by monthly 1000 µg vitamin B12 injections in the first year, or by the administration of slow-release bolus in the second. Monthly measurements were made of liveweight, serum vitamin B12 and herbage Co.

Cobalt application to the pasture effected an immediate increase in herbage Co and maintained higher values for the whole of the first grazing season. The high value found one month after application would be due to leaf adherence.
Digestibility and Utilisation of Fibre and Nitrogen by Growing Pigs given Diets Containing Sugar Beet Pulp
Authors: Stebbens H R , Morgan C A , Whittemore C T
Published: June 2019

Dried unmolassed sugar beet pulp contains complex polysaccharides which are highly fermentable in the growing pig and the neutral detergent fibre fraction is highly digestible. Fermentation in the hind gut of the pig is dependent on a supply of carbohydrate and nitrogen. The amounts of nitrogen available could limit microbial metabolism and hence sugar beet pulp digestibility at high levels of intake. The alms of the experiment were to examine:

1.

The effect of the level of protein on the digestibility of fibre from sugar beet pulp.

2.

The effect of the level of sugar beet pulp on nitrogen digestibility, nitrogen retention and nitrogen excretion.
Effects of Feeding Level, Slaughter Age and Implantation on Growth and Carcass Composition of Holstein and Friesian Steers
Authors: Keane M.G. , More O'Ferrall G.J.
Published: June 2019

In order to increase milk production per cow, Friesian cows are being bred to Holstein bulls. As yet, there are few pure-bred Holsteins in commercial production in Ireland but there are increasing numbers of Holstein x Friesian and Holstein x (Holstein x Friesian) calves available for beef production. The main difference between Holstein and Friesian steers is that the former have poorer carcass conformation. The use of anabolic agents and an increase in slaughter weight might improve carcass conformation. The objectives of the present experiment were (1) to compare the growth and carcass composition of 3/4 Holstein and Friesian steers, (2) to measure the effects of implantation with anabolic agents in both these breed types, (3) to determine the effects of a higher feeding level and delayed slaughter on carcass traits.
Recent developments in predicting the nutritive value of compound feeds for ruminants
Authors: Cooke B C
Published: June 2019

The nutritive value of compound feeds for ruminants has been classically described in terms of starch equivalent for energy and digestible crude protein for the protein fraction. Over the last ten years there has been a move to describe energy in terms of metabolisable energy and protein in terms of rumen degradable (RDP) and rumen undegradable protein (UDP). Both of these descriptions involve measurements on animals in order to derive values for individual ingredients to be used in compound feeds. The assumption is then made that these individual ingredient values are additive when the ingredients are used in the compound.

Metabolisable energy is measured in animals kept in calorimetric chambers or metabolic crates, in the latter case energy loss in the form of methane is assumed to be constant. However, data from the Rowett indicates that this is not the case, losses varying from 1.1-2.5 MJ/kg DM (Table 1). This inaccuracy can have a dramatic economic affect in feed formulation for 1MJ difference is worth £7/tonne of ingredient.
The effect of feeding intensity during pregnancy and of the length of lactation on the efficiency of meat production from once-bred gilts
Authors: Fowler V.R. , Ellis M. , Varley M.A. , Franklin M.
Published: June 2019

The efficiency of pig production can theoretically be increased by combining the two productive functions, growth and reproduction in the same animal. This is the underlying principle of the once-bred gilt. The production of once-bred gilts also serves to solve another problem, which is the difficulty of providing adequate welfare for the sow over several parities. These problems arise because the Increasingly diverse size of sows as they mature, results in fighting, particularly when sows are mixed after completing the lactation. Similar reasons also virtually necessitate individual feeding.throughout pregnancy To overcome these problems, it is widespread practice to confine sows very closely in individual stalls or farrowing pens for several years, a practice which has rightly attracted some criticism.
Effect of feeding fodder beet on feed intakes and dairy cow performance
Authors: Sabri M S , Roberts D J , Offer N W
Published: June 2019

Fodder beet is a high yielding crop with a yield of up to 12 t DM ha-1 from the roots and 2 to 5 t DM ha-1 from the tops. The root has a high metabolisable energy (ME) content, and can be used in dairy cow diets as a substitute for silage or concentrate. Pearce (1983) reported that fodder beet can be included in rations at between 10 and 25 kg cow-1 d-1 but there have been few controlled feeding experiments with modern varieties of beet under UK conditions.
Chronotropic incompetence in paediatric heart transplant recipients with prior congenital heart disease
Authors: Singh Nikki M. , Loomba Rohit S. , Kovach Joshua R. , Kindel Steven J.
Published: June 2019

Background:

Cardiopulmonary exercise testing has been used to measure functional capacity in children who have undergone a heart transplant. Cardiopulmonary exercise testing results have not been compared between children transplanted for a primary diagnosis of CHD and those with a primary diagnosis of cardiomyopathy despite differences in outcomes. This study is aimed to compare cardiopulmonary exercise testing performance between these two groups.

Methods:

Patients who underwent heart transplant with subsequent cardiopulmonary exercise testing at least 6 months after transplant at our institution were identified. They were then divided into two groups based on primary cardiac diagnosis: CHD or cardiomyopathy. Patient characteristics, echocardiograms, cardiac catheterisations, outcomes, and cardiopulmonary exercise test results were compared between the two groups.

Results:

From the total of 35 patients, 15 (43%) had CHD and 20 (57%) had cardiomyopathy. Age at transplant, kidney disease, lung disease, previous rejection, coronary vasculopathy, catheterisation, and echocardiographic data were similar between the groups. Mean time from transplant to cardiopulmonary exercise testing, exercise duration, and maximum oxygen consumption were similar in both groups. There was a difference in heart rate response with CHD heart rate response of 63 beats per minute compared to cardiomyopathy group of 78 (p = 0.028). Patients with CHD had more chronotropic incompetence than those with cardiomyopathy (p = 0.036).

Conclusion:

Primary diagnosis of CHD is associated with abnormal heart rate response and more chronotropic incompetence compared to those transplanted for cardiomyopathy.
Embolisation of ceramic-coated PDA devices into the descending thoracic aorta: probable mechanisms and retrieval strategies
Authors: Sen Supratim , Jain Sneha , Dalvi Bharat
Published: June 2019

We describe two cases of spontaneous embolisation and successful retrieval of ceramic-coated patent arterial duct devices. In both, the device embolised to the descending aorta in the absence of pulmonary hypertension and despite optimum placement. We have discussed possible mechanisms for embolisation in these patients and suggested alternative methods for device retrieval. Based on this limited experience, we conclude that for tubular ducts, ceramic-coated devices should be oversized to form a tighter waist or alternate devices may be considered.
Echinoderm skeletal crystallography and paleobiological applications
Authors: Bodenbender B. E.
Published: June 2019

The crystallographic orientations of echinoderm skeletal elements can supplement standard morphological comparisons in the exploration of echinoderm evolution. At a coarse scale, many echinoderms share a crystallographic pattern in whichcaxes radiate away from the axis of pentaradial symmetry. Within this common pattern, however,caxes of different taxa can differ dramatically in their degree of variability, angles of inclination, and relationships to the external morphology of skeletal elements. Crystallographic data reflect a variety of taxon-specific influences and therefore reveal different information in different taxa. In echinoids, orientations ofcaxes in coronal plates correlate well with high-level taxonomic groupings, whilecaxes of apical plates record modes of larval development. In blastoids,caxes of radial plates have a structural interpretation, with thecaxis oriented parallel to the orientation of the surface of the radial plate during its initial growth stages. In crinoids,caxes do not correlate with taxonomic group, plate morphology, or developmental sequence, but instead correlate with relative positions of skeletal elements on the calyx. Although their full potential has yet to be explored, the varied crystallographic patterns in echinoderms have been used to clarify skeletal structure, characterize developmental anomalies, and infer homologies of skeletal plates both within specimens and between groups. A axes are less constrained in their orientations thancaxes and offer less promise of revealing novel paleobiological information.
Early radiation of echinoderms
Authors: Sprinkle James , Guensburg Thomas E.
Published: June 2019

Echinoderms underwent a major two-part radiation that produced all of the major groups found in the fossil record between the Early Cambrian and the Middle Ordovician. A small initial radiation in the Early and Middle Cambrian produced about nine classes containing low-diversity members of the Cambrian Evolutionary Fauna. These were characterized by primitive morphology, simple ambulacral feeding structures, and the early development of a multiplated stalk or stem for attachment to skeletal fragments on a soft substrate. Several groups became extinct at the end of the Middle Cambrian, leaving the Late Cambrian as a gap of very low diversity in the fossil record of echinoderms with only four classes preserved and very few occurrences of complete specimens, mostly associated with early hardgrounds. The survivors from this interval re-expanded in the Early Ordovician and were joined by many newly evolved groups to produce a much larger radiation of more advanced, diverse, and successful echinoderms representing the Paleozoic Evolutionary Fauna on both hard and soft substrates. At least 17 classes were present by the Middle Ordovician, the all-time high point for echinoderm class diversity, and nearly all of the major ways-of-life (except for deep infaunal burrowing) had been developed. With the rise to dominance of crinoids, many less successful or archaic groups did not survive the Middle Ordovician, and echinoderm class diversity dropped further because of the mass extinction at the end of the Ordovician. This weeding-out process of other less-successful echinoderm groups continued throughout the rest of the Paleozoic, and only five classes of echinoderms have survived to the Recent from this early Paleozoic radiation.
High-Precision U-Pb Zircon Geochronology and the Stratigraphic Record: Progress and Promise
Authors: Bowring Samuel A. , Schoene Blair , Crowley James L. , Ramezani Jahandar , Condon Daniel J.
Published: June 2019

High-precision geochronological techniques have improved in the past decade to the point where volcanic ash beds interstratified with fossil-bearing rocks can be dated to a precision of 0.1% or better. The integration of high-precision U-Pb zircon geochronology with bio/chemo-stratigraphic data brings about new opportunities and challenges toward constructing a fully calibrated time scale for the geologic record, which is necessary for a thorough understanding of the distribution of time and life in Earth history. Successful implementation of geochronology as an integral tool for the paleontologist relies on a basic knowledge of its technical aspects, as well as an ability to properly evaluate and compare geochronologic results from different methods. This paper summarizes the methodology and new improvements in U-Pb zircon geochronology by isotope dilution thermal ionization mass spectrometry, specifically focused on its application to the stratigraphic record.
Detrital Zircon Geochronology by Laser-Ablation Multicollector ICPMS at the Arizona LaserChron Center
Authors: Gehrels George , Valencia Victor , Pullen Alex
Published: June 2019

Detrital zircon geochronology is rapidly evolving into a very powerful tool for determining the provenance and maximum depositional age of clastic strata. This rapid evolution is being driven by the increased availability of ion probes and laser ablation ICP mass spectrometers, which are able to generate age determinations rapidly, at moderate to low cost, and of sufficient accuracy for most applications. Improvements in current methods will probably come from enhanced precision/accuracy of age determinations, better tools for extracting critical information from age spectra, abilities to determine other types of information (e.g., REE patterns, O and Hf isotope signatures, and/or cooling ages) from the dated grains, and construction of a database that provides access to detrital zircon age determinations from around the world.
Cretaceous Records of Diatom Evolution, Radiation, and Expansion
Authors: Harwood David M. , Nikolaev Vladimir A. , Winter Diane M.
Published: June 2019

New information and discussions regarding Mesozoic diatoms presented over the last decade advanced our knowledge of their origin and early history. The oldest confirmed centric diatom fossils are presented here from the earliest Cretaceous, and araphid and raphid pennate diatoms now date from the Late Cretaceous; all from terrestrial sediments. Molecular sequencing helped clarify relationships between diatom lineages, and verify the position of diatoms within the heterokontophytes. Molecular clock approaches estimate a diatom origin near ~135 Ma, but not before 240 Ma. Biomarkers in marine sediments are able to trace a diatom presence back to the mid-Cretaceous, even when siliceous fossils are absent. Seasonal growth and encystment cycles in Late Cretaceous planktonic marine diatoms are now well documented. A biostratigraphic framework for the Late Cretaceous Arctic will aid regional and global biostratigraphic correlations. The systematic position of many new taxonomic groups is now included within a more natural classification scheme that better reflects phylogenetic relationships evident in molecular data and affirmed by biostratigraphic micropaleontology. Discussions regarding the impact of diatoms on several global systems are maturing, as more information becomes available. Four stages in diatom evolution are proposed to explain the history of radiation, extinction, and expansion into new environments and habitats during the Mesozoic.
Networks, Extinction and Paleocommunity Food Webs
Authors: Roopnarine Peter D.
Published: June 2019

Food webs represent trophic interactions among species in communities. Those interactions both structure and are structured by species richness, ecological diversity, and evolutionary processes. Geological and macroevolutionary timescales are therefore important to the understanding of food web dynamics, and there is a need for the consideration of paleocommunity food webs. The fossil record presents challenges in this regard, but the problem can be approached with combinatoric analysis and network theory. This paper is an introduction to the aspects of those disciplines relevant to the study of paleo-food webs, and explores a probabilistic and numerical approach.
A Practical Introduction to Landmark-Based Geometric Morphometrics
Authors: Webster Mark , Sheets H. David
Published: June 2019

Landmark-based geometric morphometrics is a powerful approach to quantifying biological shape, shape variation, and covariation of shape with other biotic or abiotic variables or factors. The resulting graphical representations of shape differences are visually appealing and intuitive. This paper serves as an introduction to common exploratory and confirmatory techniques in landmark-based geometric morphometrics. The issues most frequently faced by (paleo)biologists conducting studies of comparative morphology are covered. Acquisition of landmark and semilandmark data is discussed. There are several methods for superimposing landmark configurations, differing in how and in the degree to which among-configuration differences in location, scale, and size are removed. Partial Procrustes superimposition is the most widely used superimposition method and forms the basis for many subsequent operations in geometric morphometrics. Shape variation among superimposed configurations can be visualized as a scatter plot of landmark coordinates, as vectors of landmark displacement, as a thin-plate spline deformation grid, or through a principal components analysis of landmark coordinates or warp scores. The amount of difference in shape between two configurations can be quantified as the partial Procrustes distance; and shape variation within a sample can be quantified as the average partial Procrustes distance from the sample mean. Statistical testing of difference in mean shape between samples using warp scores as variables can be achieved through a standard Hotelling's T2test, MANOVA, or canonical variates analysis (CVA). A nonparametric equivalent to MANOVA or Goodall's F-test can be used in analysis of Procrustes coordinates or Procrustes distance, respectively. CVA can also be used to determine the confidence with which a priori specimen classification is supported by shape data, and to assign unclassified specimens to pre-defined groups (assuming that the specimen actually belongs in one of the pre-defined groups).

Examples involving Cambrian olenelloid trilobites are used to illustrate how the various techniques work and their practical application to data. Mathematical details of the techniques are provided as supplemental online material. A guide to conducting the analyses in the free Integrated Morphometrics Package software is provided in the appendix.
Methods for Studying Morphological Integration and Modularity
Authors: Goswami Anjali , Polly P. David
Published: June 2019

Morphological integration and modularity are closely related concepts about how different traits of an organism are correlated. Integration is the overall pattern of intercorrelation; modularity is the partitioning of integration into evolutionarily or developmentally independent blocks of traits. Modularity and integration are usually studied using quantitative phenotypic data, which can be obtained either from extant or fossil organisms. Many methods are now available to study integration and modularity, all of which involve the analysis of patterns found in trait correlation or covariance matrices. We review matrix correlation, random skewers, fluctuating asymmetry, cluster analysis, Euclidean distance matrix analysis (EDMA), graphical modelling, two-block partial least squares, RV coefficients, and theoretical matrix modelling and discuss their similarities and differences. We also review different coefficients that are used to measure correlations. We apply all the methods to cranial landmark data from and ontogenetic series of Japanese macaques,Macaca fuscatato illustrate the methods and their individual strengths and weaknesses. We conclude that the exploratory approaches (cluster analyses of various sorts) were less informative and less consistent with one another than were the results of model testing or comparative approaches. Nevertheless, we found that competing models of modularity and integration are often similar enough that they are not statistically distinguishable; we expect, therefore, that several models will often be significantly correlated with observed data.
Patterns and Processes of Ancient Reef Crises
Authors: Kiessling Wolfgang
Published: June 2019

Reef crises need to be separated from mass extinctions because they are manifested in reductions of reefal carbonate production rather than elevated extinction rates. The volume of preserved fossil reefs per unit time is perhaps the best accessible metric to assess reefal carbonate production rates in the geologic record. Although this metric is prone to biases introduced by weathering, burial, and sampling, it offers the possibility to analyze general connections between reef crises and mass extinctions. The biases can be partially corrected by looking at short-term variations and by utilizing independent proxies of sampling. Using a comprehensive database of ancient reefs and considering the generally high volatility in reefal carbonate production, we can identify five significant metazoan reef crises in the post-Cambrian Phanerozoic, only three of which correspond to traditional mass extinctions. Ancient reefs crises appear to be due to episodes of rapid CO2release and warming, rather than cooling or meteorite impacts.
Reefs Through the Looking Glass
Authors: Hubbard Dennis K.
Published: June 2019

Coral reefs have experienced a profound shift in community structure in recent decades, a pattern that contrasts with the apparent constancy of Caribbean reef zonation over the past 2 million years. The abrupt decline in branching Acropora palmata and massive frame-builders like Montastrea annularis in the Caribbean is troubling, and similar patterns have been reported from virtually every ocean. As we ponder the future of coral reefs, we must be mindful that our best monitoring records span perhaps half a century – and those are exceedingly rare. “Pristine” reefs may not have existed since Columbus sailed for the new world, and anthropogenic impacts probably extend even farther back in time.

Despite the vagaries of evolutionary change, taphonomy and time averaging, the geologic record still represents a unique source of important information about the processes that have controlled community structure and reef building in the absence of human influences. The creation of rigid and elevated structures requires calcification rates that are capable of filling the accommodation space created by rising sea level. This has been complicated over the past three to four decades as accelerated sea-level rise has been joined by a suite of stresses that probably slow accretion. Explaining the recent reef decline and posing realistic models of future change will require an understanding of carbonate cycling in the past, the processes that have been involved and a quantitative assessment of how anthropogenic stresses are affecting both.

At the least a look back in time may help to constrain the thresholds at which change might be expected to occur in the future. At best, the context gained from examining the “recent” geological past may provide insights into which possible solutions are most consistent with observed patterns at larger spatial and temporal scales.
Oxygen Isotopes in Foraminifera: Overview and Historical Review
Authors: Pearson Paul N.
Published: June 2019

Foraminiferal tests are a common component of many marine sediments. The oxygen isotope ratio (δ18O) of test calcite is frequently used to reconstruct aspects of their life environment. The δ18O depends mainly on the isotope ratio of the water it is precipitated from, the temperature of calcification, and, to a lesser extent, the carbonate ion concentration. Foraminifera and other organisms can potentially preserve their original isotope ratio for many millions of years, although diagenetic processes can alter the ratios. Work on oxygen isotope ratios of foraminifera was instrumental in the discovery of the orbital theory of the ice ages and continues to be widely used in the study of rapid climate change. Compilations of deep sea benthic foraminifer oxygen isotopes have revealed the long history of global climate change over the past 100 million years. Planktonic foraminifer oxygen isotopes are used to investigate the history of past sea surface temperatures, revealing the extent of past ‘greenhouse’ warming and global sea surface temperatures.
Applying Oxygen Isotope Paleothermometry in Deep Time
Authors: Grossman Ethan L.
Published: June 2019

Oxygen isotope paleotemperature studies of the Mesozoic and Paleozoic are based mainly on conodonts, belemnite guards, and brachiopod shells—material resistant to diagenesis and generally precipitated in oxygen isotope equilibrium with ambient water. The greatest obstacle to accurate oxygen isotope paleothermometry in deep time is uncertainty in the oxygen isotopic composition of the ambient seawater. The second greatest obstacle is fossil diagenesis. Useful application of the oxygen isotope method to brachiopod shells requires extreme care in sample screening and analyses, and is best done with scanning-electron microscopy, and petrographic and cathodoluminescence microscopy, and trace-element analysis. Correct interpretation of oxygen isotope data is greatly aided by thorough understanding of the paleolatitude, paleoecology, and depositional environment of the samples. The oxygen isotope record for the Triassic, based on brachiopod shells, is too sparse to show any distinct isotopic features. Jurassic and Early Cretaceous δ18O records, based on belemnites, show a Toarcian (Jurassic) decline (warming), a Callovian-Oxfordian acme, and an Early Cretaceous increase (cooling) to a Valanginian-Hauterivian maximum, followed by a decline (warming) to a middle Barremian minimum. Deep-time applications to oxygen isotope thermometry provide evidence for cooling and glaciation in the Ordovician, Carboniferous, and Permian. The δ18O values from Silurian and Devonian brachiopod shells and conodonts average lower than those of the remaining Phanerozoic because of the absence of continental glaciers and possibly higher temperatures (~37°?), although slightly lower (≤2%o) seawater δ18O cannot be ruled out. The hypothesis of high temperatures in the early Paleozoic implies a relatively constant hydrospheric δ18O, which is supported by clumped isotope paleotemperatures. However, more research is needed to develop methods for evaluating clumped isotope reordering in fossils. Ongoing and future research in oxygen isotope and clumped isotope thermometry hold the promise of resolving deep-time temperatures, seawater δ18O, and salinity with heretofore unavailable accuracy (±2°, ±0.4%o, and ±2 psu), providing the environmental setting for the evolution of metazoan life on Earth.
Progress in Greenhouse Climate Modeling
Authors: Huber Matthew
Published: June 2019

This article discusses past greenhouse climates with an emphasis on recent progress in the comparison of models and data in the Eocene. These past climates—about 10° warmer than modern—provide valuable lessons in the climate dynamics of a world with higher-than-modern greenhouse-gas concentrations, reduced temperature gradients, and a lack of polar ice. Some key points that emerge from this analysis are: 1) Past greenhouse climates are characterized by warmer-than-modern global mean temperatures and winter season warmth, as well as strong polar amplification of warming that generates weak meridional temperature gradients. 2) A trade-off exists between heat transport in a warmer world and a world with smaller temperature gradients; a range exists in which a warmer world with weak temperature gradients can transport as much heat as a cooler world with stronger gradients. 3) These features can be reproduced in models if global mean and tropical temperatures are allowed to increase significantly over modern values. 4) Local radiative-convective feedbacks play an important role, perhaps dominating over transport, or acting in conjunction with transport to maintain relatively warm, weak temperature gradient climates. 5) Past greenhouse climates appear to have many of the modern modes of variability from orbital to interannual. 6) Modeling efforts are most useful when done independently of proxy data; model output can then be compared with proxies to evaluate potential weaknesses in the model. 7) Model-data mismatch might be due to incorrect boundary or initial conditions or resolution, or to missing or incomplete representation of relevant physics. 8) Refinements and new developments in proxies for temperature and other variables offer much potential for discriminating among the next generation of modeled scenarios, thereby allowing a better understanding of the conditions under which greenhouse climates exist.
A Quantitative Model for Distinguishing Between Climate Change, Human Impact, and Their Synergistic Interaction as Drivers of the Late Quaternary Megafaunal Extinctions
Authors: Marshall Charles R. , Lindsey Emily L. , Villavicencio Natalia A. , Barnosky Anthony D.
Published: June 2019

A simple quantitative approach is presented for determining the relative importance of climate change and human impact in driving late Quaternary megafaunal extinctions. This method is designed to determine whether climate change or human impact alone can account for these extinctions, or whether both were important, acting independently (additively) and/or synergistically (multiplicatively). This approach is applied to the megafaunal extinction in the Última Esperanza region of southern Chile. In this region, there is a complex pattern of extinction. Records of environmental change include temperature proxies and pollen records that capture the transition from cold grasslands to warmer, moister forests, as well as evidence of initial human arrival. Uncertainty in extinction times and time of human arrival complicates the analysis, as does uncertainty about the size of local human populations, and the nature, strength, and persistence of their impacts through the late Pleistocene and early Holocene. Results of the Ultima Esperanza analysis were equivocal, with evidence for climate- and human-driven extinction, with each operating alone or additively. The results depend on the exact timing of extinctions and human arrival, and assumptions about the kinds of pressures humans put on the megafauna. There was little evidence for positive synergistic effects, while the unexpected possibility of negative synergistic interactions arose in some scenarios. Application of this quantitative approach highlights the need for higher precision dating of the extinctions and human arrival, and provides a platform for sharpening our understanding of these megafaunal extinctions.
Late Proterozoic Transitions in Climate, Oxygen, and Tectonics, and the Rise of Complex Life
Authors: Planavsky Noah J. , Tarhan Lidya G. , Bellefroid Eric J. , Evans David A. D. , Reinhard Christopher T. , Love Gordon D. , Lyons Timothy W.
Published: June 2019

The transition to the diverse and complex biosphere of the Ediacaran and early Paleozoic is the culmination of a complex history of tectonic, climate, and geochemical development. Although much of this rise occurred in the middle and late intervals of the Neoproterozoic Era (1000–541 million years ago [Ma]), the foundation for many of these developments was laid much earlier, during the latest Mesoproterozic Stenian Period (1200–1000 Ma) and early Neoproterozoic Tonian Period (1000–720 Ma). Concurrent with the development of complex ecosystems, changes in the composition, configuration, and tectonic interaction between continental plates have been proposed as major shapers of both climate and biogeochemical cycling, but there is little support in the geologic record for overriding tectonic controls. Biogeochemical evidence, however, suggests that an expansion of marine oxygen concentrations may have stabilized nutrient cycles and created more stable environmental conditions under which complex, eukaryotic life could gain a foothold and flourish. The interaction of tectonic, biogeochemical, and climate processes, as described in this paper, resulted in the establishment of habitable environments that fostered the Ediacaran and early Phanerozoic radiations of animal life and the emergence of complex, modern-style ecosystems.
Biotic and Abiotic Forcing During the Transition to Modern Grassland Ecosystems: Evolutionary and Ecological Responses of Small Mammal Communities Over the Last 5 Million Years
Authors: Fox David L. , Martin Robert A. , Roepke Elizabeth , Fetrow Anne C. , Fischer-Femal Brenden , Uno Kevin T. , Fox-Dobbs Kena , Snell Kathryn E. , Haveles Andrew , Polissar Pratigya J.
Published: June 2019

Understanding the origin of modern communities is a fundamental goal of ecology, but reconstructing communities with durations of 103–106 years requires data from the fossil record. Early Pliocene to latest Pleistocene faunas and sediments in the Meade Basin and modern soils and rodents from the same area are used to examine the role of environmental change in the emergence of the modern community. Paleoenvironmental proxies measured on modern surface soils and paleosols are described, and faunal dynamics of fossil rodents are discussed. Mean annual precipitation (MAP) was estimated from elemental concentrations and magnetic properties, and warm-season temperature and δ18O of soil water was estimated using carbonate isotope paleothermometry on pedogenic nodules. MAP and temperature estimates from paleosols exhibit no short-term variability, no long-term trends, and generally bracket modern values. Estimated soil water δ18O values increased through time, suggesting aridification played a role in the evolution of the regional grassland ecosystem. Carbon isotope analyses of biomarkers are used to examine the abundance of C4 grasses, which suggest more C4 biomass and more variability in C4 biomass than carbonate proxies. Rodent species richness remained constant due to balanced rates of extinction and immigration, both of which show episodic spikes consistent with a balance between forcing mechanisms that result in equilibrium on long time scales. Overall, these results suggest that different mechanisms of faunal change may be acting at different time scales, although the stratigraphic resolution of paleoenvironmental proxies needs to be increased, and body size and dietary distributions of rodents need to be determined before which processes of change are most important can be decided.
Two Ways of Explaining Actions
Authors: Dancy Jonathan
Published: June 2019

In my Practical Reality I argued that the reasons for which we act are not to be conceived of as psychological states of ourselves, but as real (or maybe only supposed) states of the world. The main reason for saying this was that only thus can we make sense of the idea that it is possible to act for a good reason. The good reasons we have for doing this action rather than that one consist mainly of features of the situations in which we find ourselves; they do not consist in our believing certain things about those situations. For instance, the reason for my helping that person is that she is in trouble and I am the only person around. It is not that I believe both that she is in trouble and that I am the only person around. Give that the (good) reason to help is that she is in trouble etc., it must be possible for my reason for helping to be just that, if it is indeed possible for one to act for a good reason. In fact, this sort of thing must be the normal arrangement. The reasons why we act, therefore, that is, our reasons for doing what we do, are not standardly to be conceived as states of ourselves, but as features of our situations.
Normativity and the Will
Authors: Wallace R. Jay
Published: June 2019

If there is room for a substantial conception of the will in contemporary theorizing about human agency, it is most likely to be found in the vicinity of the phenomenon of normativity. Rational agency is distinctively responsive to the agent's acknowledgment of reasons, in the basic sense of considerations that speak for and against the alternatives for action that are available. Furthermore, it is natural to suppose that this kind of responsiveness to reasons is possible only for creatures who possess certain unusual volitional powers, beyond the bare susceptibility to beliefs and desires necessary for the kind of rudimentary agency of which the higher animals are arguably capable.
Can Libertarians Make Promises?
Authors: Mele Alfred
Published: June 2019

Libertarians hold that free action and moral responsibility are incompatible with determinism and that some human beings occasionally act freely and are morally responsible for some of what they do. Can libertarians who know both that they are right and that they are free make sincere promises? Peter van Inwagen, a libertarian, contends that they cannot—at least when they assume that should they do what they promise to do, they would do it freely. Probably, this strikes many readers as a surprising thesis for a libertarian to hold. In light of van Inwagen's holding it, the title of his essay—‘Free Will Remains a Mystery’—may seem unsurprising.
The Ontogenesis of Human Identity
Authors: Boniolo Giovanni
Published: June 2019

“<>.

Das hiess doch: Wenn du dir gewisse Tatsachen anders denkst, sie anders beschreibst, als sie sind, dann kannst du die Anwendung gewisser Begriffe dir nicht mehr vorstellen, weil die Regeln ihrer Anwendung kein Analogon unter den neuen Umstanden haben.” (L. Wittgenstein,Zettel, § 350)
Evo-devo: A New Evolutionary Paradigm?
Authors: Ruse Michael
Published: June 2019

The homologies of process within morphogenetic fields provide some of the best evidence for evolution—just as skeletal and organ homologies did earlier. Thus, the evidence for evolution is better than ever. The role of natural selection in evolution, however, is seen to play less an important role. It is merely a filter for unsuccessful morphologies generated by development. Population genetics is destined to change if it is not to become as irrelevant to evolution as Newtonian mechanics is to contemporary physics. (Gilbert, Opitz, and Raff 1996, 368)