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Ice scallops are a small-scale (5–20 cm) quasi-periodic ripple pattern that occurs at the ice–water interface. Previous work has suggested that scallops form due to a self-reinforcing interaction between an evolving ice-surface geometry, an adjacent turbulent flow field and the resulting differential melt rates that occur along the interface. In this study, we perform a series of laboratory experiments in a refrigerated flume to quantitatively investigate the mechanisms of scallop formation and evolution in high resolution. Using particle image velocimetry, we probe an evolving ice–water boundary layer at sub-millimetre scales and 15 Hz frequency. Our data reveal three distinct regimes of ice–water interface evolution: a transition from flat to scalloped ice; an equilibrium scallop geometry; and an adjusting scallop interface. We find that scalloped-ice geometry produces a clear modification to the ice–water boundary layer, characterized by a time-mean recirculating eddy feature that forms in the scallop trough. Our primary finding is that scallops form due to a self-reinforcing feedback between the ice-interface geometry and shear production of turbulent kinetic energy in the flow interior. The length of this shear production zone is therefore hypothesized to set the scallop wavelength.
Bipolar disorder (BD) and obsessive compulsive disorder (OCD) are prevalent, comorbid, and disabling conditions, often characterized by early onset and chronic course. When comorbid, OCD and BD can determine a more pernicious course of illness, posing therapeutic challenges for clinicians. Available reports on prevalence and clinical characteristics of comorbidity between BD and OCD showed mixed results, likely depending on the primary diagnosis of analyzed samples.
We assessed prevalence and clinical characteristics of BD comorbidity in a large international sample of patients with primary OCD (n = 401), through the International College of Obsessive–Compulsive Spectrum Disorders (ICOCS) snapshot database, by comparing OCD subjects with vs without BD comorbidity.
Among primary OCD patients, 6.2% showed comorbidity with BD. OCD patients with vs without BD comorbidity more frequently had a previous hospitalization (p < 0.001) and current augmentation therapies (p < 0.001). They also showed greater severity of OCD (p < 0.001), as measured by the Yale–Brown Obsessive Compulsive Scale (Y-BOCS).
These findings from a large international sample indicate that approximately 1 out of 16 patients with primary OCD may additionally have BD comorbidity along with other specific clinical characteristics, including more frequent previous hospitalizations, more complex therapeutic regimens, and a greater severity of OCD. Prospective international studies are needed to confirm our findings.
As paleobiology continues to address an ever broader array of questions, it becomes increasingly important to interpret confidently the meaning of the pattern of fossil occurrences as found in outcrop. To this end, sequence stratigraphy is an important tool for paleobiologists because it predicts the distribution of unconformities, facies changes, and changes in sedimentation rate, all factors known from numerous previous studies to affect the quality of the fossil record. Computer simulations now make it possible not only to model sequence architecture within sedimentary basins, but also to model the occurrence of fossils within those basins. These models generate predictions regarding the stratigraphic distribution of first and last occurrences, changes in species abundance, changes in species morphology, and the distribution of gaps in fossil ranges. Although confirmation of some of these predictions has been found in field studies, the extent to which these predictions describe the fossil record in general is still unknown. If the predicted patterns of fossil occurrences are found to be widespread, it will suggest that a relatively simple model of fossil occurrences in outcrops could become a new tool for solving a wide array of paleobiologic and biostratigraphic problems. With such models, paleobiologists and biostratigraphers will be able to use model data to test the accuracy of newly developed methods of analysis.
The European badger (Meles meles) is Ireland's largest terrestrial carnivore. Since first being identified as a wildlife reservoir of bovine tuberculosis in 1974 there has been an increased research focus into the behaviour of these ecologically important mammals in the Republic of Ireland (ROI). However, to date there has never been an assessment of the helminth parasite community of Irish badgers. This study of 289 badgers found helminth infection to be endemic within the sample population and we report for the first time the prevalence, abundance, intensity and aggregation of helminth infection in ROI. Eight distinct helminth taxa were recorded: Aelurostrongylus falciformis, Crenosoma melesi, Eucoleus aerophilus, Species A, Strongyloides spp., Uncinaria criniformis, and two unidentifiable but morphologically distinct nematodes. All helminths belong to the taxon Nematoda, and this is the first report of an exclusively nematode community across the badger's Eurasian distribution. Infection was not significantly influenced by the host sex, region of origin or season of sampling.
Proglacial environments are ideal for studying the development of soils through the changes of rocks exposed by glacier retreat to weathering and microbial processes. Carbon (C) and nitrogen (N) contents as well as soil pH and soil elemental compositions are thought to be dominant factors structuring the bacterial, archaeal and fungal communities in the early stages of soil ecosystem formation. However, the functional linkages between C and N contents, soil composition and microbial community structures remain poorly understood. Here, we describe a multivariate analysis of geochemical properties and associated microbial community structures between a moraine and a glaciofluvial outwash in the proglacial area of a High Arctic glacier (Longyearbreen, Svalbard). Our results reveal distinct differences in developmental stages and heterogeneity between the moraine and the glaciofluvial outwash. We observed significant relationships between C and N contents, δ13Corg and δ15N isotopic ratios, weathering and microbial abundance and community structures. We suggest that the observed differences in microbial and geochemical parameters between the moraine and the glaciofluvial outwash are primarily a result of geomorphological variations of the proglacial terrain.
Numerical simulations of neutral metacommunities are used here to predict the effects of growth and shrinkage of metacommunities, as well as their separation and merging caused by continental collision and rifting and their secondary eustatic effects. Although growth and shrinkage of metacommunities predictably change diversity, separating and merging metacommunities have counterintuitive effects. Separating and merging metacommunities change diversity within the individual areas, especially so for smaller areas, but they cause no change in total diversity of the system, contrary to previous predictions. The response times of metacommunities are likely to be geologically undetectable except for enormously large systems. These models can be used to predict the plate-tectonic effects on the diversity of terrestrial, coastal-marine, deep-marine, and oceanic-island systems. Of these, global and regional coastal-marine systems are the most acutely sensitive to the changes in area and fragmentation caused by plate tectonics. Oceanic-island systems also experience global and regional changes in diversity during supercontinent breakup and assembly, with the global effects driven by the changing length of volcanic arcs, and the regional effects also driven by secondary eustatic changes in shallow-marine area. Although individual terrestrial provinces or continents may experience substantial changes in diversity from rifting and collision, global terrestrial diversity should be unchanged except for the relatively modest contributions caused by the secondary eustatic effects on land area. These changes in diversity may be reinforced or counteracted by the changing latitudinal position of metacommunities.
This review focuses on current understanding of prenatal, prepubertal and post-pubertal development of the male reproductive system of cattle. The critical developmental events occur during the first 3 to 4 months of gestation and the first ~6 to 9 months after birth. The Wilms Tumor-1 and SRY proteins play critical roles in early development and differentiation of the fetal testis, which in turn drives gestational development of the entire male reproductive system. The hypothalamic–pituitary–gonadal axis matures earlier in the bovine fetus than other domestic species with descent of the testes into the scrotum occurring around the 4th month of gestation. An array of congenital abnormalities affecting the reproductive system of bulls has been reported and most are considered to be heritable, although the mode of inheritance in most cases has not been fully defined. Early postnatal detection of most of these abnormalities is problematic as clinical signs are generally not expressed until after puberty. Development of genomic markers for these abnormalities would enable early culling of affected calves in seedstock herds. The postnatal early sustained increase in lutenising hormone secretion cues the rapid growth of the testes in the bull calf leading to the onset of puberty. There is good evidence that both genetic and environmental factors, in particular postnatal nutrition, control or influence development and maturation of the reproductive system. For example, in Bos taurus genotypes which have had sustained genetic selection pressure applied for fertility, and where young bulls are managed on a moderate to high plane of nutrition puberty typically occurs at 8 to 12 months of age. However, in many Bos indicus genotypes where there has been little selection pressure for fertility and where young bulls are reared on a low plane of nutrition, puberty typically occurs between 15 to 17 months. Our understanding of the control and expression of sexual behavior in bulls is limited, particularly in B. indicus genotypes.
The longstanding association between the major histocompatibility complex (MHC) locus and schizophrenia (SZ) risk has recently been accounted for, partially, by structural variation at the complement component 4 (C4) gene. This structural variation generates varying levels of C4 RNA expression, and genetic information from the MHC region can now be used to predict C4 RNA expression in the brain. Increased predicted C4A RNA expression is associated with the risk of SZ, and C4 is reported to influence synaptic pruning in animal models.
Based on our previous studies associating MHC SZ risk variants with poorer memory performance, we tested whether increased predicted C4A RNA expression was associated with reduced memory function in a large (n = 1238) dataset of psychosis cases and healthy participants, and with altered task-dependent cortical activation in a subset of these samples.
We observed that increased predicted C4A RNA expression predicted poorer performance on measures of memory recall (p = 0.016, corrected). Furthermore, in healthy participants, we found that increased predicted C4A RNA expression was associated with a pattern of reduced cortical activity in middle temporal cortex during a measure of visual processing (p < 0.05, corrected).
These data suggest that the effects of C4 on cognition were observable at both a cortical and behavioural level, and may represent one mechanism by which illness risk is mediated. As such, deficits in learning and memory may represent a therapeutic target for new molecular developments aimed at altering C4’s developmental role.
Theories of human aggression can inform research, policy, and practice in organizations. One such theory, victim precipitation, originated in the field of criminology. According to this perspective, some victims invite abuse through their personalities, styles of speech or dress, actions, and even their inactions. That is, they are partly at fault for the wrongdoing of others. This notion is gaining purchase in industrial and organizational (I-O) psychology as an explanation for workplace mistreatment. The first half of our article provides an overview and critique of the victim precipitation hypothesis. After tracing its history, we review the flaws of victim precipitation as catalogued by scientists and practitioners over several decades. We also consider real-world implications of victim precipitation thinking, such as the exoneration of violent criminals. Confident that I-O can do better, the second half of this article highlights alternative frameworks for researching and redressing hostile work behavior. In addition, we discuss a broad analytic paradigm—perpetrator predation—as a way to understand workplace abuse without blaming the abused. We take the position that these alternative perspectives offer stronger, more practical, and more progressive explanations for workplace mistreatment. Victim precipitation, we conclude, is an archaic ideology. Criminologists have long since abandoned it, and so should we.
Little information is available on how physical processing of cereals affects crude protein (CP) degradation dynamics in equines. In two experiments the effects of two physical processing methods (micronisation and extrusion) on in situ degradation of CP in barley, maize and peas in the caecum of ponies were investigated.
In experiment 1, three caecally-fistulated mature Welsh-cross pony geldings (approx. LW 270kg) were used whilst two of these ponies were used in experiment 2. In both experiments ponies were offered ad libitum grass hay plus minerals. Incubation bags (monofilament polyester, 6.5 x 20cm, 41μm pores, 16mg/cm2 sample size) contained either unprocessed barley (UB), micronised barley (MB) or extruded barley (EB) (experiment 1) and either unprocessed maize (UM), micronised maize (MM), extruded maize (EM), unprocessed peas (UP), micronised peas (MP) or extruded peas (EP) (experiment 2).
A wide variety of starch based feeds are available for inclusion in equine diets. These feeds may be subjected to physical processing (micronisation or extrusion) prior to inclusion. This experiment evaluates a range of starch based feedstuffs using an in vitro batch culture technique.
A total of 15 feedstuffs were incubated in vitro with an inocula prepared from freshly voided faeces which was collected from six ponies fed grass hay ad libitum. The feeds were five starch based feedstuffs; i.e: maize (M), peas (P), wheat (W), naked oats (NO) or barley (Ba) in one of three physically processed forms i.e: unprocessed (Unp), micronised (Mic) or extruded (Ext). All feeds were ground through a 1.0mm screen prior to incubation. Cumulative gas production (GP) was measured using the pressure transducer technique of Theodorou et al (1994) throughout a 72 h incubation period.
Previous work has shown that the mobile bag technique (MBT) can be used to study the dynamics of digestive processes in the whole tract of ponies (Hyslop et al, 1998). This experiment further develops the MBT as a method to study feed degradation dynamics over time in the pre-caecal segment of the digestive tract of ponies.
Two caecally-fistulated mature Welsh-cross pony geldings (LW 270kg) were offered 4kg of dry matter (DM) per day of a 1:3 rolled barley:hay cube mix plus minerals, in 2 equal meals per day at 09:00 and 17:00h. Grass hay was also offered ad libitum between 17:00 and 09:00h. Two sizes of mobile bag (6 x 1 cm Ø-large and 4 x 1 cm Ø- small) made from monofilament polyester with a 7 μm pore size were used.
Maize and peas that have undergone physical processing are used routinely in cereal mixes for equines. However, little information is available on how physical processing of maize and peas affects degradation dynamics in equines. This experiment examines the effect of two physical processing methods (micronisation and extrusion) on in situ degradation of maize and peas in the caecum of ponies
Two caecally-fistulated mature Welsh-cross pony geldings (approx. LW 270kg) were offered ad libitum grass hay plus minerals. Incubation bags (monofilament polyester 6.5 x 20cm, 41? m pores, 16mg/cm2 sample size) containing either unprocessed maize (UM), micronised maize (MM), extruded maize (EM), unprocessed peas (UP), micronised peas (MP) or extruded peas (EP) were incubated in the caecum for fixed times according to both a forward (0, 2, 4, 6, 12, 8, 24, 48h) and reverse (48, 24, 8, 4, 12, 6, 2, 0h) incubation sequence. For each feedstuff residues from each time were bulked within pony and across incubation sequence for subsequent analysis of dry matter (DM) and starch (STC).
Estimates of digesta passage through specific segments of the alimentary tract are a vital component of modelling approaches which attempt to quantitatively partition digestive processes in equines. This study reports results from three studies where digesta passage of Chromium (Cr) mordanted feeds was determined in the caecum of ponies.
Caecal outflow rates were determined during three in vivo apparent digestibility studies conducted using three caecally-fistulated ponies as described by Moore-Colyer et al, (1999) for studies 1 and 2; and McLean et al, (1999) for study 3. Pony basal diets consisted of unmolassed sugar beet pulp (USBP), hay cubes (HC) or a 2:1 mix of oat hulls:naked oats (OHNO) in study 1; a 1:1 mix of USBP:HC (USHC) in study 2 and either 100% HC or one of 3 diets consisting of a 1:1 HC:barley mix where the barley was either rolled (RBHC), micronised (MBHC) or extruded (EBHC) in study 3.
Processed cereals are used routinely in diets for equines but little information is available on how physical processing affects the digestibility of cereals in equines. This study examines the effects of three physical processing methods (rolling, micronisation and extrusion) on the in vivo apparent digestibility of barley fed to ponies.
Three mature caecally-fistulated Welsh-cross pony geldings, (LW 284kg ± 3.8kg) were used in a 3 x 4 incomplete latin square changeover design experiment consisting of four 21 day periods. Each period comprised a sixteen day adaptation phase and a five day recording phase when apparent digestibility in vivo was determined. Ponies were offered 4kg dry matter (DM) per day of either 100% hay cubes (HC) or one of three diets consisting of a 50:50 barley:hay cubes mix. The barley in the mixed diets was either rolled barley (RB), micronised barley (MB) or extruded barley (EB). Diets were offered in 2 equal meals per day fed at 09:00 and 17:00 hours respectively.
Particle size (PS) may be reduced when feeds are ground through small screen sizes leading to increased losses from artificial fibre bags during in situ or mobile bag experiments in equines. Smaller PS may also alter the water holding capacity (WHC) of feeds which in turn may alter bag transit times during mobile bag experiments. This study examines PS and WHC in a range of starch based equine feedstuffs ground through two screen sizes.
Five feedstuffs (F) were used ie: barley (B), maize (M), peas (P), wheat (W) and naked oats (NO). Feedstuffs were subjected to three types of physical pre-processing (Pr) ie: unprocessed (Un), micronised (Mi) or extruded (Ex) and then ground through either a 1.0 or 0.5 mm screen size (SS). For PS analysis a 25g sample of each feedstuff was sieved through a stack of 11 sieves ranging in pore diameter between 45 μm and 2 mm using a mechanical shaker for 20 min.
In vitro techniques have been developed to study the fermentation kinetics of a wide range of animal feedstuffs but relatively few studies have been conducted specifically with purified feed constituents. This study uses the pressure transducer technique of Theodorou et al (1994) to record cumulative gas production (GP) when six purified starch sources were incubated in vitro.
Three replicates of six commercially available purified (98%) starch sources were incubated in vitro with an inoculum prepared from freshly voided faeces collected from six ponies fed hay ad libitum. The starches were a purified wheat starch (ABRA), four purified wheat starches that had been chemically modified with sodium tri-metaphosphate (V1, V21, V33 & V65) and a purified pea starch (PEA). GP was measured using the pressure transducer technique throughout a 72 h incubation period. At the end of the incubation period DM loss (DML) in vitro was determined by filtration.