bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro Fermentation of the Non-Starch Polysaccahride Fraction of Tropical Forage Legumes
Authors: Longland A.C. , Pilgrim R.D. , Thorpe J. , Lister S.J. , Morris P. , Theodorou M.K.
Published: January 2018

The fibre fraction (= non-starch polysaccharides; NSP) of tropical forage legumes is a potentially important source of dietary energy. Such legumes, however often contain tannins which can reduce the fermentability of the NSP fraction. In this study, the monosaccharide composition and in vitro digestibility of the NSP fraction of eleven tropical forage legumes varying in condensed tannin content, were investigated.

Milled, lyophilised leaves of 5 species of forage legume from Ethiopia, Sesbania goetzei (SG), Sesbania sesban (SS) Leucaena leucocephala (LL), Acacia cyanophylla (AC), Chamaecytisus palmensis (CP)) and six from Colombia, Calliandra sp. 29400 (C), Dioclea guianensis (DG), Flemingia macrophylla 77409 (FM) Tadehagi sp. 23227 (T23), 13269 (T69) and 13275 (T75)) were used. One gram samples were fermented at 39°C for 7 d under anaerobic conditions in modified Van Soest medium inoculated with bovine rumen fluid (5 replicates per species). At the end of the fermentation period, residues were filtered, washed with distilled water and lyophilised. The NSP content and composition of the original samples and their residues were determined by the method of Englyst and Cummings (1984). The bound, soluble and total condensed tannin contents of the original samples were determined by the method of Terrill et al. (1992).
Dry Matter and Protein Degradability of Leucaena
Authors: Fekadu T. , Acamovic T. , Stewart C.S. , Topps J.H.
Published: January 2018

There are major limitations imposed on animal production in tropical areas of the world. Some of the limitations are caused by the lack of availability of protein for animal consumption. This lack of dietary protein can be attributed to lack of pasture because of adverse environmental conditions, overgrazing which can lead to erosion and thus a poorer environment, poor soil condition and nutritional status. Often, grazing of mixed pastures and the provision of cereal crop residues are the fundamentals of ruminant nutrition in most tropical countries. These dietary substrates are frequently N-deficient and also frequently very high in fibre which limits digestibility. Such a dietary regime may maintain animals at low levels of production and may prevent their death during prolonged dry periods but good productivity is precluded. The inclusion of legumes, either browse or forage, in pastures can reduce or alleviate some of the problems mentioned above and provide dietary protein. Leucaena leucocephala has been shown to be a suitable leguminous forage supplement for ruminants in arid areas of the world including Zimbabwe. It is not however without problems thus there is considerable interest in producing different cultivars.
Evaluation of the Nutritional Characteristics of Tropical Feeds Using the Pressure Transducer Gas Measurement Technique
Authors: Sileshi Z , Owen E , Theodorou M K , Dhanoa M S , France J
Published: January 2018

The nylon bag technique is widely used for assessing the kinetics of forage disappearance in the rumen (Ørskov, Hovell & Mould, 1980); the technique also holds promise for predicting the intake of roughages (Ørskov, Reid & Kay, 1988). The nylon bag technique is being advocated as being especially suitable for tropical conditions where laboratory facilities are limited. However the technique has a capacity limitation. Due to its dependence on in situ incubation in the rumen of fistulated animals, only small numbers of forage samples can be assessed at any one time. Thus the technique is of limited value in laboratories undertaking routine screening of large numbers of samples, for the purposes of feed evaluation and for use in plant breeding programmes.
The use of velocity of ultrasound to monitor body composition in lactating cows
Authors: Cooper A. , Aston K. , Dhanoa M.S. , McAllan A.B.
Published: January 2018

Previous studies have shown that using non-invasive techniques such as the measurement of the velocity of ultrasound (VOS) through live animals (Sim. 1983) can, in the body of the lactating dairy cow, provide reliable estimates of chemical composition and energy content (Ivings,Gibb,Dhanoa and Fisher.1993). In this study VOS was used to monitor the changes in body composition of dairy cows fed concentrates containing differing levels of crude protein (CP).

Fifty-five Holstein-Friesian cows were offered 5kg of fresh concentrate containing 156(L),245(M) or 338(H)g CP/kg dry matter (DM) together with grass silage (162g CP/kg DM,D value 0.723,ME 12.3 MJ/kg DM and pH 3.72) offered ad-libitum over weeks 4 to 21 of lactation. There were five treatments designated LL,LH,MM,HL, HH with a change of CP level where appropriate in week 13. Five cows were selected from each treatment and VOS measurements taken from two sites on the hindquarters (B and Bl) at weeks 12,15,18 and 21. Liveweights were also taken at this time.
Extensification of beef production - Effects of fertiliser N level on herbage yield, grazing days and performance of beef steers.
Authors: Keane M.G.
Published: January 2018

Existing grassland-based male beef production systems use 200 to 300 kg N/ha and require 9 to 11 t silage plus 700 to 1200 kg concentrates per animal produced. Output is in the range 700 to 800 kg carcass per ha. Arising from the reform of the Common Agricultural Policy (CAP) of the European Union, such beef production systems must be extensified if all the animals are to qualify for the special beef premium. The reformed CAP specifies a maximum stocking density of 2 livestock units (LU) per ha whereas existing systems operate at an intensity of 2.5 to 2.7 LU per ha. The objectives of the present study were (1) to extensify beef production (from dairy bred calves) so as to obtain more production from grazed grass and less from silage and concentrates and (2) to measure the effects of reduced fertiliser N usage on herbage production, stock carrying capacity and animal performance.
Measurements of the acid binding capacity of ingredients used in Diets for starter pigs
Authors: Lawlor P.G. , Lynchi P.B. , Caffrey P.J.
Published: January 2018

Starter diets of low acid binding capacity (ABC) are sometimes recommended to ensure an acidic environment in the stomach of newly weaned pigs. A low stomach pH aids protein digestion and provides a barrier against the passage of bacteria into the small intestine. A diet of low ABC can be formulated through careful selection of ingredients (Jasaitis et al., 1987). The present study was undertaken to measure the ABC of feed ingredients commonly used in pig starter feeds and to determine if diet ABC can be predicted from the ABC of the ingredients.
Effect of chemical structure of fats upon their apparent digestible energy Value when fed to young pigs.
Authors: Powles J. , Wiseman J , Cole D J A , Hardy B
Published: January 2018

Previous studies have examined the effect of the degree of saturation (as measured by th3 ratio of unsaturated to saturated fatty acids, U/S) and free fatty acid (FFA) content on the digestible energy (DE) value of fats fed to growing/ finishing pigs. However, there have been no detailed studies with the immediate post-weaning pig, which was the objective of the current programme.

Two fats of differing degrees of saturation (U/S) and their respective acid oils of high free fatty acid (FFA) content were obtained for evaluation. Fats were Soyabean Oil (SO), Soyabean Acid Oil (SAO), Tallow (T) and Tallow Acid Oil (TAO).
An assessment, using physiological parameters, of the welfare of group housed gilts on three feeding systems
Authors: Stewart A H , Edwards S A , Mackenzie A M
Published: January 2018

The assessment of well-being is of prime importance in the development of new production systems. For meaningful conclusions to be drawn, every aspect under the broad headings of physical, physiological and behavioural well being should be studied. There are a number of instances where, in extreme circumstances, physiological parameters have been shown to affect health and production, and are considered by some to be useful in determining long term welfare status. There is, however, evidence to suggest that the interactions between physiological functions are too complex to allow simple conclusions. As part of a comprehensive study into welfare of group housed gilts (Stewart et al 1993) this paper describes the results of an immune challenge, an adrenal function test (ACTH challenge) and adrenal weight and how they are associated with other welfare parameters.
The effect of liquid feeding in a deep straw system on sow behaviour and welfare
Authors: Baynes P.J. , Hunter E.J. , Guise H.J. , Penny R.H.C.
Published: January 2018

A survey of dry sow housing across England (Baynes and Hunter, 1993) was conducted to assess farmers' future plans and opinions regarding the onset of the 1999 ban relating to stall and tether housing systems. Results from this survey showed that approximately one third of English pig producers currently with these types of systems were undecided as to which system to choose. A number of case studies are currently being conducted on existing group-housed systems to contribute to a data base on group housing options.

Sows were housed in a general purpose barn which had been divided into 12 pens, each housing ten sows. Sows were liquid fed once a day in a common trough with partial barriers. Total space allowance was 2.96m2/sow, of which 1.23m2was kennelled.
Dry sow housing-induced anatomical differences and the effects on lying behaviour
Authors: Marchant J.N. , Broom D.M.
Published: January 2018

Over the last few decades, the modern domestic pig has been genetically selected to maximise weight and length of back for meat production. Consequently, its body shape has changed and the physical acts of standing up and lying down have become difficult and relatively uncontrolled, even without any modification that housing systems may impose. Confined housing systems restrict the amount of exercise that locomotory muscles perform, and may affect muscular conformation and strength. It is possible, therefore, that confinement will decrease any element of muscular control during standing and lying, even further. The objective of this study was to determine any relationship between muscular conformation and time taken to lie down in sows housed in different dry sow systems.
The effect of a simple conversion of a tether house on sow welfare
Authors: Baynes P.J. , Hunter E.J. , Guise H.J. , Penny R.H.C.
Published: January 2018

A survey of dry sow housing across England (Baynes and Hunter, 1993) indicated that 30% of producers currently with confinement systems would like to convert their existing sow buildings to conform with the ban on stall and tether systems in 1999. This study assessed the feasibility of a minimal cost conversion of part of a tether house in which the sows were liquid fed.

Sows were housed in a 21 year old tether house capable of housing 152 sows in four rows. The middle section of the house consisted of two rows of tethers, back to back, and part of this was gated off to create two pens, each capable of holding 10 sows in two rows of five. Total space allowance was 14m2/sow. Sows were of mixed weights and parities and all had previous experience of the tether house. Both groups were observed for three hours immediately after mixing, for two hours feeding on the following day, and for two hours on nine subsequent days. Eight categories of agonistic interaction (head swing with mouth closed, head swing with mouth open, push, attempted bite/slash, bite/slash, mount, vulva bite and fight of more than ten seconds), space usage and skin lesions (scored from one to five on eight regions of the body - Stewartet al, 1993) were recorded during each observation period. Sow weight and condition (scored from one to five - Whittemore, 1980) were assessed on entry to the building at four weeks post-weaning and on exit, approximately five days pre-farrowing.
Effect of three lactation housing systems on sow and piglet performance and behaviour
Authors: Hatet G , Edwards S A , Gall K , Arey D S
Published: January 2018

Confinement of sows in farrowing crates and early weaning of piglets are two major areas of concern in relation to animal welfare in intensive pig production systems. In this project, two alternative lactation systems in which these potential stressors are absent or reduced were evaluated.

36 sows and litters were used in an experiment to evaluate, from weekly performance records and observations of behaviour, two alternative strategies for housing and management during lactation in comparison with a conventional current system:

(1)

Family system (F): Sows were housed throughout in groups of four with voluntary access farrowing pens. Piglets remained with the sows for 12 weeks and a boar was introduced after 3 weeks to induce oestrus.

(2)

Multisuckling system (M): Sows farrowed in individual crates but were grouped in fours in straw pens after 2 weeks. Piglets remained with the sows for 12 weeks and a boar was introduced after 3 weeks.

(3)

Conventional commercial system (C). Sows remained in part-slatted, unbedded farrowing crates throughout a four week lactation. Piglets weaned into flat decks and transfered after four weeks into fully slatted grower pens.
The effect of enrichment on the behaviour, welfare and performance of early-weaned piglets in slatted flatdeck housing
Authors: Moore E.A. , Broom D.M. , Simmins P.H.
Published: January 2018

Consideration of the welfare of the weaner pig requires knowledge of the needs of the animal and determining how these needs may be accommodated in commercial housing. Piglets raised in extensive conditions spend much of their day engaged in exploratory behaviours, including rooting, nosing, shaking and chewing objects. Research indicates that exploratory activity is important for the animal's well-being. Flatdeck accommodation with slatted flooring is coming under increasing critisism on welfare grounds in that it offers little outlet for such behaviours. As a consequence, piglets tend to redirect these behaviours towards penmates which is undesirable. Supplementing the pen with objects which enable normal exploratory behaviours may create an environment more suited to the needs of the piglet. The aim of this study was to investigate the effect of environmental enrichment on the behaviour, welfare and performance of early-weaned piglets.
A comparison of the performance of Turkish and Syrian strains of Awassi ewes at two levels of nutrition
Authors: Treacher T T , Bahhady F , Hreitani H , Termanini A
Published: January 2018

Although milk is an important product of sheep systems using the Awassi breed in the Near East, typically giving 25% of the gross income, there is little information on the yields of Awassi ewes at defined levels of nutrition. The Awassi is the dominant breed of sheep in the Near East. It is the only breed in Jordan, Lebanon and Syria, which have a total sheep population of 16.9 million. In Iraq about 50% of the 7.8 million sheep are Awassis. There are also approximately 1 million Awassi sheep in Turkey, mainly in the south along the border with Syria. Turkish Awassi ewes have been selected for milk yield for many years at the Ceylanpinar State Farm.

In 1991, ICARDA purchased 40 ewes, aged 2 years, from the Ceylanpinar flock. In 1992, these ewes and 40 ewes selected at random from 2 year old ewes in the flock at ICARDA's Tel Hadya station at Aleppo, in northern Syria, were compared, using two levels of nutrition in lactation. The ewes in the ICARDA flock are typical of well managed flocks in northern Syria.
The relative importance of energy and protein in the concentrate on intake and yield of milk constituents by freisland ewes offered hay ad-libitum
Authors: Wilkinson R.G. , Minter C.M. , Duffy G. , Celerier J.
Published: January 2018

Increasing the level of concentrate fed to lactating ruminants reduces forage intake, but increases the yield of milk and milk constituents (Aston et al. 1991). However, the proportion of the total response due to additional metabolisable energy (ME) or crude protein supply (CP) is unclear. Recent work with dairy cows (Aston et al. 1992) suggests that additional ME or CP fed as concentrate reduced and slightly increased silage intake respectively. Additional CP had twice the effect on milk and three times the effect on protein yield than additional ME. However, ME and CP were equally important in determining fat yield. The objective of the trial was to investigate whether dairy sheep respond to additional ME or CP supply as concentrate in a similar way to dairy cows.

Three concentrate diets were formulated to contain 13.0 MJ/kg DM ME and either 100 (A), 200 (B) or 400 (C) g/kg DM CP. After weaning (6 weeks), 24 mature Freisland ewes were housed individually, and allocated by liveweight and initial milk yield to receive concentrate DM at daily rates of 0.8 kg, providing 10.4 MJ/day ME and 160 (B) or 320 (C) g/day CP (LLP, LHP), or 1.6 kg, providing 20.8 MJ/day ME and 160 (A) or 320 (B) g/day CP (HLP, HHP). The trial lasted 8 weeks and was analysed as a 2 X 2 factorial design.
Comparison of the response of secondary hair follicles of cashmere and angora goats to prolactin and melatonin in vitro
Authors: Ibraheem M. , Galbraith H. , Scaife J.R.
Published: January 2018

Angora and Cashmere goats produce two distinctive major fibres. The hair coat of the Angora goat consists essentially of a single fleece of Mohair grown by secondary hair follicles with a limited production of guard hair from primary follicles. The average fibre diameter ranges from 22 to 45 urn. In contrast, the Cashmere bearing goat has a double coat comprising coarse guard hair produced by primary follicles with the fine cashmere underhair (preferably 19 μm diameter or less) produced by secondary hair follicles. In the Angora goat, the fibres grow essentially continuously while in cashmere, hair follicle activity is determined largely by seasonal changes in photoperiod. The objective of this study was to investigate the effects of prolactin and melatonin, hormones implicated in the photoperiodic response, on the pattern of growth of secondary hair follicles isolated and maintained in vitro.
Bentazon Response of the U.S. Plant Introduction Collection of Pepper (Capsicumsp.)
Authors: Harrison Howard F. , Fery Richard L.
Published: January 2018

The U.S. Plant Introduction Collection for six pepper species (2694 accessions) was evaluated for tolerance to bentazon in a field study. Based on injury ratings,Capsicum annuum, C. chinense, andC. frutescensaccessions were mostly intermediate in response to bentazon with relatively few highly tolerant or susceptible. Most ofC. bacatum, C. chacoense, andC. pubescensand the unspeciated accessions were susceptible. Greenhouse experiments indicated that although most of the tolerant selections were highly tolerant, none was more tolerant than theC. annuumcultivars ‘Santaka’ or ‘Bohemian Chili’. None of the susceptible selections were more susceptible to bentazon than theC. annuumcultivar ‘Sweet Banana’. Individual plants that were highly tolerant were self-pollinated to produce progeny that were all highly bentazon tolerant, but none was more tolerant than Santaka or Bohemian Chili.
Effect of Date of Treatment of Johnsongrass (Sorghum halepense) on Soybean (Glycine max) Yields
Authors: McWhorter Chester G.
Published: January 2018

In a 6-yr field study, johnsongrass growing in ‘Forrest’ soybeans for the entire growing season reduced yields 45% in the year with most rainfall and 69% in the year with least rainfall. Yields of soybeans grown without johnsongrass competition were 56% higher in the year with the most rainfall than in the year with least rainfall. Yields of soybeans with full-season competition were reduced 75% from those in the year with most rainfall as compared with those in the year with least rainfall. The number of weeks of johnsongrass competition required to significantly reduce soybean yields varied from 3 wk, in the year with least rainfall, to 8 wk, in the year with most rainfall. Nine applications of sethoxydim at 0.84 kg ai ha-1or haloxyfop at 0.55 kg ai ha-1each year did not reduce soybean growth or yields.
Annual Grass Control in Cool Season Turf with Sequential Applications of Unlike Preemergence Herbicides
Authors: Reicher Zachary J. , Throssell Clark S. , Lefton Jeff L.
Published: January 2018

Control of goosegrass and large crabgrass with different preemergence herbicides for the initial and sequential application was studied at four locations in Indiana. Pendimethalin at 1.1 kg ai ha-1was used as the initial application in all treatments. Sequential treatments applied 6 wk after the initial treatment consisted of: 2.2 kg ha-1benefin; 1.4/0.7 kg ha-1benefin/trifluralin; 8.4 kg ha-1bensulide; 11.8 kg ha-1DCPA; 0.6 kg ha-1dithiopyr; 2.2 kg ha-1oxadiazon; 1.1 kg ha-1pendimethalin; or 0.6 kg ha-1prodiamine. Dithiopyr at 0.6 kg ha-1with no initial application was also included. Highest large crabgrass control ratings were obtained through September with pendimethalin + pendimethalin, pendimethalin + dithiopyr, and dithiopyr alone postemergence. All other sequential applications tested improved control over a single application of 1.1 kg ha-1pendimethalin, but rarely gave adequate season long control.
An Improved Invert Emulsion with High Water Retention for Mycoherbicide Delivery
Authors: Connick William J. , Daigle Donald J. , Quimby Paul C.
Published: January 2018

An invert emulsion with low viscosity and excellent water-holding properties was developed for delivery of fungal weed pathogens (mycoherbicides). Alternaria cassiae, a pathogen of sicklepod, proliferated after incorporation of spores in the emulsion. The oil phase (CDQ-1) contained paraffin wax, a paraffinic spray oil, and an unsaturated monoglyceride emulsifier (Myverol 18–99). The oil phase was mixed 1:1 (by weight) with water to form the invert, which was sprayed onto glass plates for testing of water retention properties. Water contents ranged from 22% (with A. cassiae present) to 41% (without fungus) for 0.6 to 0.7-mm2 spray deposits after 24-h storage at 21 C and 65% relative humidity. An invert emulsion containing lactofen was prepared using the CDQ-1 formulation.
A Decade of Weed Contests
Authors: Oliver Lawrence R.
Published: January 2018

The first weed contest was held at the Eli Lilly Research Farm at Albany, GA, in late May 1980. From the original idea of David Teem of FL, a contest evolved that was sanctioned by the Southern Weed Science Society in 1981. In August 1981, the first North Central Collegiate Weed Science Contest was held at the Agri-Growth Research Farm, Hollandale, MN. An undergraduate division was established in 1982. The Northeast Collegiate Weed Science Contest began in 1983 at the Wye Research Center in Queenstown, MD, with both graduate and undergraduate formats. The North Central contest annually has the most participants followed by the Southern and Northeast contests. Representatives from 39 universities have competed in at least one contest. The three contests follow a similar format that includes four events: plant and seed identification of weed species, identification of herbicides from plant symptoms, calibration of herbicide application equipment, and crop/weed problems and recommendations. Preparation by universities has varied from minimal to establishing a class to prepare students for the contest. Regardless of the level of preparation, the weed contests have developed into one of the most anticipated and worthwhile experiences for students and university and industry personnel.
Governing for Creativity
Authors: Casper Gerhard
Published: January 2018

The paper addresses the question of how, in a research-intensive university, choices should be made to determine strategies that are appropriate for ambitious and creative institutions committed to both teaching and research at a high level. The paper calls for accountable real leadership at the university level and at lower levels. It also calls for organizational flexibility and flexibility in the allocation of material and immaterial resources.
Promoting Creativity at Work – Implications for Scientific Creativity
Authors: Ohly Sandra
Published: January 2018

Creativity is the generation of novel and useful ideas. Organizations, including universities and other research institutions, need to develop novel and useful products to satisfy constantly evolving customer needs. Furthermore, organizational procedures and processes develop over time, and continuous improvements in processes contribute to organizational efficiency. Thus, the development of novel and useful ideas in relation to products, procedures and services is mandated from many employees in modern organizations, including researchers and scientists. This creativity can take on many different forms, for example unconventional solutions to a wide variety of problems related to research, teaching and administration. Because many of these problems are comparable to that of workers in all kinds of jobs, I believe it is possible to draw on the rich knowledge in the field of organizational creativity to provide some insights into how to foster scientific creativity. The work of researchers and scientists is in many ways comparable to that of knowledge workers in other kinds of organizations: they are high-level employees who apply knowledge to do their work, oftentimes using creative thinking. A rich body of literature has dealt with creativity in these jobs where creativity is a core requirement, and has examined the organizational factors related to creativity. Before I summarize this research and highlight some important research findings concerning the rewards for creativity, the design of jobs, the processes leading to creativity, the organizational climate, and daily work events associated with creativity, I will disentangle different forms of creativity at work and describe a general model of creativity in the context of work.
The Modernization of Landscapes during the Late Paleozoic-Early Mesozoic
Authors: Kerp Hans
Published: January 2018

Since their first appearance in the Middle-Late Silurian, land plants have played an increasingly important role in shaping terrestrial ecosystems and landscapes. It is difficult to overestimate their role because they form the framework for terrestrial ecosystems, provide habitats for terrestrial animals, form an important part of the food chain, affect weathering processes and have a direct impact on soil formation, and, last but not least, play a primary role in the oxygen/carbon cycles.
The Paleobiology of Pollination and its Precursors
Authors: Labandeira Conrad C.
Published: January 2018

Perhaps the most conspicuous of associations between insects and plants is pollination. Pollinating insects are typically the first and most obvious of interactions between insects and plants when one encounters a montane meadow or a tropical woodland. The complex ecological structure of insect pollinators and their host plants is a central focus within the ever-expanding discipline of plant-insect interactions. The relationships between plants and insects have provided the empirical documentation of many case-studies that have resulted in the formulation of biological principles and construction of theoretical models, such as the role of foraging strategy on optimal plant-resource use, the advantages of specialized versus generalized host preferences as viable feeding strategies, and whether “pollination syndromes” are meaningful descriptions that relate flower type to insect mouthpart structure and behavior (Roubik, 1989; Ollerton, 1996; Waser et al., 1996; Johnson and Steiner, 2000). Much of the recent extensive discussion of plant-insect associations has centered on understanding the origin, maintenance, and evolutionary change in plant/pollinator associations at ecological time scales and increasingly at longer-term macroevolutionary time intervals (Armbruster, 1992; Pellmyr and Leebens-Mack, 1999). Such classical plant-insect association studies—cycads and cycad weevils, figs and fig wasps, and yuccas and yucca moths—were explored at modern time scales and currently are being examined through a long-term geologic component that involves colonization models based on cladogenetic events of plant and insect associates, buttressed by the fossil record (Farrell, 1998; Pellmyr and Leebens-Mack, 1999; A. Herre,pers. comm.). In addition to tracing modern pollination to the earlier Cenozoic and later Mesozoic, there is a resurgence in understanding the evolutionary history of earlier palynivore taxa (spore, prepollen and pollen consumers), which led toward pollination as a mutualism (Scott et al., 1992).
EXPANDER GRAPHS AND SIEVING IN COMBINATORIAL STRUCTURES
Authors: JOUVE FLORENT , SERENI JEAN-SÉBASTIEN
Published: January 2018

We prove a general large-sieve statement in the context of random walks on subgraphs of a given graph. This can be seen as a generalization of previously known results where one performs a random walk on a group enjoying a strong spectral gap property. In such a context the point is to exhibit a strong uniform expansion property for a suitable family of Cayley graphs on quotients. In our combinatorial approach, this is replaced by a result of Alon–Roichman about expanding properties of random Cayley graphs. Applying the general setting we show, for instance, that with high probability (in a strong explicit sense) random coloured subsets of integers contain monochromatic (nonempty) subsets summing to $0$, and that a random colouring of the edges of a complete graph contains a monochromatic triangle.
The carbon and oxygen isotopic records of fossils from the Lower Oxford Clay
Authors: Anderson T. F. , Popp B. N. , HO L. Z. , Williams A. C.
Published: January 2018

The excellent preservation of calcareous invertebrates and phosphatic vertebrates in the Lower Oxford Clay provides a good opportunity for paleooceanographic reconstruction based on stable isotopic abundances. We present here our initial results and interpretations on carbon and oxygen isotopic analyses on fossils of different depth habitats. Benthic fossils include epifaunal oysters and infaunal nuculacean bivalves. We also analyzed “pendant” bivalves whose depth habitat is uncertain. Fossil nekton are represented by ammonites and belemnites. Organisms that inhabited the uppermost part of the water column are represented by marine reptiles, such as icthyosaurs and plesiosaurs, and probable pelagic fish.

The oxygen isotopic compositions of calcareous benthos and nekton overlap substantially (δ180 = −2 to +1 permil vs. PDB). The wide scatter in δ180 values probably reflects physiological (non-equilibrium) effects in calcification rather than paleoenvironmental variations. Mean δ180 values for oysters, pendant bivalves, and belemnites (all calcitic) and nuculacean bivalves (aragonitic) correspond to precipitation at isotopic equilibrium with non-glacial seawater at temperatures of 15°-18°. The mean isotopic paleotemperature for ammonites (aragonitic) is slightly higher (20°) but is probably not significantly different from those for other calcareous macro-invertebrates. Preliminary oxygen isotopic results on phosphate extracted from bones, teeth, and gill rays correspond to paleotemperatures of 20°–25°.

Carbon isotopic results are limited to data from calcareous benthos and nekton. δ 13C values for individual taxa are quite variable (+2 to +5 permil for aragonitic fossils, 0 to +3 permil for calcitic fossils), suggesting physiological isotope effects. Nonetheless, mean δ 13C values are consistent with calcification in seawater having a carbon isotopic composition similar to that of modern average seawater. The presumably high flux of 13C-depleted CO2 into bottom waters from the diagenesis of sedimentary organic matter is not recorded in the carbon isotopic composition of benthic fossils.

Thermal stratification implied by the oxygen isotopic record suggests the penetration of cool, nutrient-rich waters into the Lower Oxford Clay sea. Upward advection of deep waters together with runoff from adjacent landmasses must have provided sufficient nutrients to maintain the inferred high productivity of surface waters. The influence of productivity on the carbon isotopic composition of surface waters will be tested by the analysis of calcareous phytoplankton.
Self-organized criticality and the fractal scaling of a predator-prey interaction
Authors: Aronson Richard B.
Published: January 2018

In many cases, it is not possible to explain evolutionary-scale patterns by analogy to ecological processes. However, in at least some cases, biological interactions appear amenable to such extrapolation. The paleobiological literature contains examples of predation, competition, and herbivory in which the dynamics are similar on multiple spatiotemporal scales.

Dense populations of epifaunal, suspension-feeding ophiuroids, or brittlestar beds, are widely distributed, but they are rare and are restricted in their habitat distribution. On a small scale (meters to kilometers, hours to days), brittlestar bed distribution in the British Isles and the Bahamas is limited by predatory fishes and crabs. On an intermediate scale (tens to hundreds of kilometers, decades to centuries), predation by seastars may cause cycles of ophiuroid abundance in the western English Channel, beyond the stringent restrictions imposed by fish and crab predators. On a large scale (globally, millions to tens of millions of years), the Jurassic decline of brittlestar beds is associated with the diversification of predatory teleosts, neoselachian sharks, and decapod crustaceans.

Small-scale predator-ophiuroid interactions sum to produce analogous intermediate- and large-scale interactions. Predation effects on brittlestar beds appear to be scale-independent, or fractal. Fractal scaling may be a consequence of self-organized criticality, an inherent property of large, interactive systems.
Floodplains and paleosols in the Siwalik Miocene sequence: implications for taphonomy and paleoecology of faunas
Authors: Behrensmeyer Anna K. , Quade Jay , Willis Brian
Published: January 2018

The Siwalik fluvial deposits of Pakistan are characterized by varying proportions of red to brown silts, fine sands, and minor clays representing overbank deposition. In the Chinji Formation (~15–10.5 Ma), floodplain facies consist of overlapping packages of: 1) well-bedded siltstones and occasional sheet sands or small channel sands, 2) an overlying transitional zone with increased bioturbation and minor pedogenesis, 3) a capping paleosol. These packages are 5–6 m thick and pinch out laterally over 1–2 km; they appear to represent crevasse-splay lobes that aggraded rapidly into low-lying wet areas and then became stable land surfaces. The cycle was repeated as aggradation of the major rivers and/or local subsidence transformed the topographic highs into lows where sedimentation again buried soil surfaces. Floodplains in the Nagri Formation (~10.5–9 Ma) were associated with a larger channel system and were less complex, and those of the Dhok Pathan Formation (~9–6 Ma) were influenced by several contemporaneous river systems and again became more complex.

Paleosols are superimposed on all lithofacies and occur every 4–10 m thoughout the 3500 m sequence where overbank deposits are dominant. Paleomagnetic calibration of the Siwalik sequence indicates that paleosols represent 10–50K yrs, on average. Individual paleosols are red-orange or red-brown, 1.6–4.8 m thick, have abundant evidence of bioturbation, ped structure, clay cutans and a zone depleted in matrix carbonate above a lower zone with carbonate precipitates. A long-term record of Siwalik vegetation in Pakistan is contained in the carbon isotope ratios of paleosol carbonate. There is no evidence that paleosols varied in maturity with distance from the major channels; instead vertical and lateral facies relationships were controlled by shifting crevasse-splay lobes and overbank channels.

The processes of overbank sedimentation in the Siwalik sequence have important consequences for preservation of vertebrate faunas. Most of the 800+ fossil localities occur in channel fills within overbank facies; relatively few are associated with paleosols or the coarse deposits of major channels. The frequency of overbank channel fills varies through the different formations, resulting in uneven sampling of the vertebrate faunas. Most skeletal remains are attritrional, and bones are disassociated and fragmentary but otherwise well-preserved. This is partly a consequence of bioturbation and minor transport followed by rapid burial within the abandoned channels. The ecological setting of the Siwalik biota was controlled by a mosaic of floodplain environments that changed in complexity through time. In contrast to the Eocene Bighorn Basin floodplains, there was no simple lateral relationship of habitat types with distance from the major channels.
Paleobiogeography of Jurassic foraminifera from central Kutch, Western India
Authors: Bhalla S.N.
Published: January 2018

A prolific assemblage of foraminifera dominated by vaginulinids and nodosariids recovered from Callovian-Oxfordian sequence exposed in central Kutch, Western India, is correlated with Jurassic foraminiferal assemblages from other localities of Kutch, a few other Indian regions and also from certain regions of the world. The Kutch assemblage has a distinct Tethyan affinity. A comparative study indicates that during Dogger and Malm epochs, Kutch was having sea connections with Central Arabia, Iran, Afghanistan, Rajasthan, Somalia and Madagascar.
Paleontological methods in environmental science
Authors: Brush Grace S. , Khan Humaira
Published: January 2018

Long term environmental changes, induced both by natural and anthropogenic causes, cannot be assessed by looking solely at historical records of temperature, rainfall, water quality, etc. Frequently, such records are nonexistent. Where they do exist, they are often too short to be of much use. However, sediments contain a stratigraphic record of environmental change that allows comparison of the historic period influenced largely by humans, with prehistoric time when climate was the major determinant of environmental conditions.

The stratigraphic record contains various fossilized organic materials which reflect environmental conditions at the time of the their deposition. Most abundant are pollen and spores of aquatic and terrestrial plants. Correspondence between pollen assemblages and vegetation has been found in all parts of the world. Therefore stratigraphic changes in pollen taxa reveal much information regarding the vegetational history of a region. Knowledge of the ecological requirements of various taxa can then be used to infer past climatic conditions. For example, dominance of Juglans (walnut) pollen indicates wet conditions while abundance of Pteridium (bracken fern) spores is an indicator of fire, suggesting drier conditions. Pollen can also be used to trace human disturbance to the environment. Sharp increases in the pollen of Ambrosia (ragweed) in sediment cores indicate large scale land clearance by man.

Seeds preserved in sediments provide another measure of temporal vegetational change. Generally, seeds are not dispersed far from the parent plant; hence they provide a more local record of vegetation than pollen. A decrease in seeds of aquatic plants and increase in seeds of higher ground taxa when accompanied by increased sedimentation rates is an indicator of infilling of an aquatic environment. If unaccompanied by increased sedimentation, the change more likely represents lowering of sea level. Disappearance of seeds of taxa sensitive to turbidity and eutrophication provide another long term record of human disturbance.

Distributions of diatoms are affected by temperature, salinity, oxygen, light availability and nutrient levels in the water. Therefore changes in diatom species preserved in the sediments can be used as indicators of climate, turbidity, anoxia and eutrophication in aquatic ecosystems.

Many inorganic substances preserved in sediments also provide a long term record of changes in the environment. Nitrogen and phosphorus can be measured in cores and used as a surrogate record of water quality in lakes and estuaries. Sharp increases in sedimentary accumulation of metals record wastewater discharge and fuel emissions, related to human activity.
Evolution of interactive niche breadth and its consequences in paleoecosystem networks
Authors: Burns Thomas P.
Published: January 2018

An ecological community, the living part of an ecosystem, can be conceived as a network of interacting organisms. This network specifies the biotic environment influencing the evolution and population dynamics of those organisms. The number and relative strengths of the interactions between an organism and the others in its environment defined by that network (termed network fittedness) are determined in part by heritable morphological and behavioral traits of the organism. This property, fittedness, can be quantified using Levins' (1968) measure of niche breadth applied to the probabilities of interacting with the other species of organisms in the network, i.e., fittedness is a measure of interactive niche breadth. It is hypothesized that organisms optimize fittedness and that the optimum increases with the variability of the environment.

These two hypotheses are combined in a model that predicts the dynamics of interactive structure of ecosystems and the fittednesses of their component organisms, both of which arise from the evolution and coevolution of populations of organisms and their ecological dynamics, including immigration and local extinction. This model applies to interactions of all sorts: predation, competition, mutualisms, etc.

This model leads to predictions on the evolution and stasis of organisms' morphological and behavioural traits and on how the variance in density of individual taxa change through a coherent spatiotemporal interval experiencing relatively undisturbed abiotic environmental conditions. The model predicts that, after an initial period of high turnover of species and dominance by species with high fittedness (generalists), the community will come to comprise an increasing proportion of organisms with narrow interactive niche breadths (specialists), the turnover of generalists will increase as they are replaced by specialists or they evolve specializations reflected in their morphology or behavior, and the turnover of specialist species will decrease. Population densities will fluctuate less as surviving species become more and more likely to interact with fewer species which also fluctuate less. Assuming an inverse relationship between fittedness and the sensitivity of populations to fluctuations in density of the species with which they interact, decreasing fittedness of the species in the community will lead to increasing sensitivity to the inevitable and unpredictable biotic or abiotic environmental perturbations, such as species invasions or increasing sedimentation rates. Moreover, the set of species forming the community will be increasingly sensitive to relatively small perturbations the greater the interval between perturbations, such that the timing of perturbations becomes important in determining the severity of the community's response. These predictions should be testable in the fossil record.
Pre-Ediacaran multicellular life: harbinger of a Phanerozoic radiation
Authors: Butterfield Nicholas J.
Published: January 2018

Multicellular organisms must have had a substantial pre-Ediacaran history, but the fossil evidence is sparse and often equivocal. The taxonomic resolution necessary to constrain phylogenetic hypotheses is limited largely to Lagerstätte-grade fossils that retain evidence of diagnostic cell division patterns. Uniseriate and multiseriate filaments in the 1267-723 Ma Hunting Formation, Somerset Island, derive from transverse and longitudinal intercalary cell division programs indistinguishable from those of the modern red alga Bangia, and establish a significantly pre-Ediacaran datum point for the Rhodophyta. Likewise, on the basis of a distinctive “segregative cell division”, three taxa of siphonocladalean green algae (Chlorophyta) are identified in the ca. 750 Ma Svanbergfjellet Formation, Spitsbergen. Process-bearing vesicles in the Svanbergfjellet sequence further compare with the germinating zoospores of the modern chromophyte alga Vaucheria, while convincing Vaucheria-like thalli are reported from ca. 900 Ma deposits in Siberia. The broad co-occurrence of multicellular Rhodophyta, Chlorophyta, and Chromophyta by at least 750 Ma ago accords well with molecular evidence that suggests the three principal algal clades diverged from a common ancestor during a brief but marked radiation relatively late in eukaryote evolution.

Complex multicellularity featuring cellular and tissue(?) differentiation is also encountered in the pre-Ediacaran fossil record. A large ornate form in the Svanbergfjellet succession preserves at least six readily distinguishable cell types and, despite its taxonomic uncertainty, can be characterized as at least as complex as the most complex modern algae or fungi. No cellularity is preserved in the late Proterozoic macrofossil Tawuia; however, SEM and light microscopy of its isolated wall reveal a complex histology suggestive of a relatively advanced grade of multicellularity. Another Svanbergfjellet macrofossil has a distinct wall structure and bears a terminal pair of large reniform structures; if these prove to be truly bilaterally symmetrical, this fossil represents a grade of organization otherwise not recognized until the Ediacaran. Further analysis of these and other pre-Ediacaran ‘problematica’ may clarify their taxonomic relationships and promises to resolve at least some of the ‘Cambrian explosion’ into a meaningful sequence of evolutionary change.
Interpretation of Anisian (Middle Triassic) marine invertebrate faunas from the southwest Pacific
Authors: Campbell Hamish J.
Published: January 2018

Early to Middle Triassic marine successions are remarkably lacking in the Southern Hemisphere. It would seem that the best developed and most fossiliferous sequences are preserved in New Zealand. To a lesser extent, successions of Early to Middle Triassic age are known from New Caledonia, New Guinea, the Gympie Basin of Eastern Australia, offshore Western Australia, and western South America (in particular Chile).

Anisian marine faunas were first collected in New Zealand (Etalian local stage) in the 1940s but it was not until 1953 that their age significance was correctly recognised by Marwick. This was later confirmed by Kummel. Since then an unpublished doctoral study has been completed on the paleontology and biostratigraphy of the Anisian succession within the Murihiku terrane of Southland, South Island, New Zealand. A conclusion of this study, based on ammonoid correlations, was that the cosmopolitan halobiid bivalve Daonella appears earlier in New Zealand than it does in North America.

Recent investigations post-date the advent of the tectonostratigraphic terrane concept and suggest that an Anisian fossil record is preserved in at least three terranes in New Zealand (Murihiku, Dun Mountain - Maitai and Torlesse terranes), and two terranes in New Caledonia (probably correlatives of the Murihiku and Torlesse terranes of New Zealand). Analysis of the faunal content of these various terranes suggests that although there are some facies differences (litho and bio), there is little obvious basis for recognition of distinct paleobiogeographic provenance.

A corollary to this research on Anisian faunas is the recognition that the New Zealand ammonoid faunas previously considered to be Early Triassic (Malakovian local stage; Murihiku terrane) by Kummel are almost certainly Anisian. However, this does not imply that there isn't an Early Triassic sedimentary record. Significant thicknesses of apparently unfossiliferous sequence are present in each of the relevant terranes. Two isolated Early Triassic ammonoid faunas are now known from elsewhere in New Zealand but from tectonically complex settings in Brook Street (?) and Dun Mountain - Maitai terranes.