Litterfall from two eucalypt woodlands in central Queensland

The mean annual litterfall at two dry woodland sites in central Queensland was 1129 kg ha(-1) for an open E. populnea F. Muell. woodland (n = 2 years), and 2318 kg ha(-1) for a woodland dominated by E. cambageana Maiden (n = 1 year). Leaves formed the largest component of total litterfall, which varied seasonally with a spring-summer maximum. Annual litterfall at these sites conformed with a pattern of decreasing litter production with declining annual rainfall, consistent with a range of eucalypt-dominated communities.

The central pathway of primary olfactory axons is abnormal in mice lacking the N-CAM-180 isoform

Although N-CAM has previously been implicated in the growth and fasciculation of axons, the development of axon tracts in transgenic mice with a targeted deletion of the 180-kD isoform of the neural cell adhesion molecule (N-CAM-180) appears grossly normal in comparison to wild-type mice. We examined the organization of the olfactory nerve projection from the olfactory neuroepithelium to glomeruli in the olfactory bulb of postnatal N-CAM-180 null mutant mice. Immunostaining for olfactory marker protein revealed the normal presence of fully mature primary olfactory neurons within the olfactory neuroepithelium of mutant mice. The axons of these neurons form an olfactory nerve, enter the nerve fiber layer of the olfactory bulb, and terminate in olfactory glomeruli as in wild-type control animals. The olfactory bulb is smaller and the nerve fiber layer is relatively thicker in mutants than in wild-type mice. Previous studies have revealed that the plant lectin Dolichos biflorus agglutinin (DBA) clearly stains the perikarya and axons of a subpopulation of primary olfactory neurons. Thus, DBA staining enabled the morphology of the olfactory nerve pathway to be examined at higher resolution in both control and mutant animals. Despite a normal spatial pattern of DBA-stained neurons within the nasal cavity, there was a distorted axonal projection of these neurons onto the surface of the olfactory bulb in N-CAM-180 null mutants. In particular, DBA-stained axons formed fewer and smaller glomeruli in the olfactory bulbs of mutants in comparison to wild-type mice. Many primary olfactory axons failed to exit the nerve fiber layer and contribute to glomerular formation. These results indicate that N-CAM-180 plays an important role in the growth and fasciculation of primary olfactory axons and is essential for normal development of olfactory glomeruli. (C) 1997 John Wiley & Sons, Inc.

Peripheral withdrawal recruits distinct central nuclei in morphine-dependent rats

This study examined if brain pathways in morphine-dependent rats are activated by opioid withdrawal precipitated outside the central nervous system. Withdrawal precipitated with a peripherally acting quaternary opioid antagonist (naloxone methiodide) increased Fos expression but caused a more restricted pattern of neuronal activation than systemic withdrawal (precipitated with naloxone which enters the brain). There was no effect on locus coeruleus and significantly smaller increases in Fos neurons were produced in most other areas. However in the ventrolateral medulla (A1/C1 catecholamine neurons), nucleus of the solitary tract (A2/C2 catecholamine neurons), lateral parabrachial nucleus, supramamillary nucleus, bed nucleus of the stria terminalis. accumbens core and medial prefrontal cortex no differences in the withdrawal treatments were detected. We have shown that peripheral opioid withdrawal can affect central nervous system pathways. Crown Copyright (C) 2001 Published by Elsevier Science Ltd. All rights reserved.

Expression of glycoproteins in the vomeronasal organ reveals a novel spatiotemporal pattern of sensory neurone maturation

The main olfactory and the accessory olfactory systems are both anatomically and functionally distinct chemosensory systems. The primary sensory neurones of the accessory olfactory system are sequestered in the vomeronasal organ (VNO), where they express pheromone receptors, which are unrelated to the odorant receptors expressed in the principal nasal cavity. We have identified a 240 kDa glycoprotein (VNO240) that is selectively expressed by sensory neurones in the VNO but not in the main olfactory neuroepithelium of mouse. VNO240 is first expressed at embryonic day 20.5 by a small subpopulation of sensory neurones residing within the central region of the crescent-shaped VNO, Although VNO240 was detected in neuronal perikarya at this age, it was not observed in the axons in the accessory olfactory bulb until postnatal day 3.5, This delayed appearance in the accessory olfactory bulb suggests that VNO240 is involved in the functional maturation of VNO neurones rather than in axon growth and targeting to the bulb, During the first 2 postnatal weeks, the population of neurones expressing VNO240 spread peripherally, and by adulthood all primary sensory neurones in the VNO appeared to be expressing this molecule. Similar patterns of expression were also observed for NOC-1, a previously characterized glycoform of the neural cell adhesion molecule NCAM, To date, differential expression of VNO-specific molecules has only been reported along the rostrocaudal axis or at different apical-basal levels in the neuroepithelium. This is the first demonstration of a centroperipheral wave of expression of molecules in the VNO, These results indicate that mechanisms controlling the molecular differentiation of VNO neurones must involve spatial cues organised, not only about orthogonal axes, but also about a centroperipheral axis, Moreover, expression about this centroperipheral axis also involves a temporal component because the subpopulation of neurones expressing VNO240 and NOC-1 increases during postnatal maturation. (C) 2001 John Wiley & Sons, Inc.

mecA locus diversity in methicillin-resistant Staphylococcus aureus isolates in Brisbane, Australia, and the development of a novel diagnostic procedure for the Western Samoan phage pattern clone

An emerging public health phenomenon is the increasing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections that are acquired outside of health care facilities. One lineage of community-acquired MRSA (CA-MRSA) is known as the Western Samoan phage pattern (WSPP) clone. The central aim of this study was to develop an efficient genotyping procedure for the identification of WSPP isolates. The approach taken was to make use of the highly variable region downstream of mecA in combination with a single nucleotide polymorphism (SNP) defined by the S. aureus multilocus sequence typing (MLST) database. The premise was that a combinatorial genotyping method that interrogated both a highly variable region and the genomic backbone would deliver a high degree of informative power relative to the number of genetic polymorphisms-interrogated. Thirty-five MRSA isolates were used for this study, and their gene contents and order downstream of mecA were determined. The CA-MRSA isolates were found to contain a truncated mecA downstream region consisting of mecA-HVR-IS431 mec-dcs-Ins117, and a PCR-based method for identifying this structure was developed. The hospital-acquired isolates were found to contain eight different mecA downstream regions, three of which were novel. The Minimum SNPs computer software program was used to mine the S. aureus MLST database, and the arcC 2726 polymorph was identified as 82% discriminatory for ST-30. A real-time PCR assay was developed to interrogate this SNP. We found that the assay for the truncated mecA downstream region in combination with the interrogation of arcC position 272 provided an unambiguous identification of WSPP isolates.

Archaeological Identification and Significance of ÉSAG (Agricultural Storage Pits) at Kaman-Kalehöyük, Central Anatolia

Evidence for the presence of storage pits described in Hittite texts by the Sumerogram "ÉSAG" is presented from Kaman-Kalehöyük, a multi-period tell site in central Turkey occupied during the second and first millennia BC. Small earthen pits matching the description of "ÉSAG" were part of the normal suite of domestic installations at the site throughout the period. Similar to pits seen across western Eurasia, they were probably used to store seed corn or seed for trade. Large earthen pits (>7m in diameter) were also present that matched the description of the "ÉSAG" form, and in some cases contained archaeological cereal remains. Evidence from Kaman shows "ÉSAG" were part of Anatolian life for at least 4,000 years and suggests that the term was generic for lined, earthen storage pits. The presence of so many small pits at Kaman-Kalehöyük showed that it was an agricultural production site for much of its existence. The appearance of the large pits, confined to the Hittite period, reflects centralised control of grain supply, probably by the Hittite Kingdom, and fits a pattern seen at other sites in the region during the second millennium BC. /// Hitit metinlerinde Sumerogram "ÉSAG" ile tanimlanan depo çukurlarinin varliğina dair kanit, Orta Anadolu'da M.Ö. İkinci ve Birinci binde iskan edilmiş çok dönemli bir yerleşim alani olan Kaman-Kalehöyük'ten taninmaktadir. Küçük toprak çukurlar "ÉSAG" in tanimlamasina uygun olarak bu dönem süresince normal ev düzeninin bir parçasi olarak karşimiza çikmiştir. Çukurlar, Bati Avrasya'daki benzer çukurlar gibi olasilikla ticaret maksadi ile misir tohumu ya da tohum muhafaza etmişlerdir. "ÉSAG" formunun tanimina uyan büyük toprak çukurlara (çapi 7m. den büyük) rağmen bunlarin tahil depolama ile ilgili bağlantilari tam olarak belirlenmemiştir. Kaman'daki delil, "ÉSAG" in en az 4,000 yildir Anadolu yaşaminin bir parçasi olduğunu ve bu sözcüğün sivanmiş toprak çukurlar için kullanildiğini işaret etmektedir. Kaman-Kalehöyük'te ele geçen birçok küçük çukur, yerleşimin varliğini sürdürdüǧü sürecin büyük bir bölümünde zirai üretim yapildiğini göstermektedir. Hitit Döneminde büyük çukurlarin ortaya çikmasi muhtemelen Hitit Kralliği tarafindan gerçekleştirilen tahil tedarikinin merkezi kontrolünü yansitmakta ve M.Ö. İkinci binde bu bölgedeki diğer yerleşim alanlarinda görülen şekle uymaktadir.

EphA4 regulates central nervous system vascular formation

Molecules involved in axon guidance have recently also been shown to play a role in blood vessel guidance. To examine whether axon guidance molecules, such as the EphA4 receptor tyrosine kinase, might also play a role in development of the central nervous system (CNS) vasculature and repair following CNS injury, we examined wild-type and EphA4 null mutant (-/-) mice. EphA4-/- mice exhibited an abnormal CNS vascular structure in both the cerebral cortex and the spinal cord, with disorganized branching and a 30% smaller diameter. During development, EphA4 was expressed on endothelial cells. This pattern of expression was not maintained in the adult. After spinal cord injury in wild-type mice, expression of EphA4 was markedly up-regulated on activated astrocytes, many of which were tightly associated with blood vessels. In EphA4-/- spinal cord following injury, astrocytes were not as tightly associated with blood vessels as the wild-type astrocytes. In uninjured EphA4-/- mice, the blood-brain barrier (BBB) appeared normal, but it showed prolonged leakage following spinal cord injury. These results support a role for EphA4 in CNS vascular formation and guidance during development and an additional role in BBB repair.

Screening of obstructive and central apnoea/hypopnoea in children using variability: A preliminary study

Aim: Polysomnography (PSG) is the current standard protocol for sleep disordered breathing (SDB) investigation in children. Presently, there are limited reliable screening tests for both central (CE) and obstructive (OE) respiratory events. This study compared three indices, derived from pulse oximetry and electrocardiogram ( ECG), with the PSG gold standard. These indices were heart rate (HR) variability, arterial blood oxygen de-saturation (SaO(2)) and pulse transit time (PTT). Methods: 15 children (12 male) from routine PSG studies were recruited (aged 3 - 14 years). The characteristics of the three indices were based on known criteria for respiratory events (RPE). Their estimation singly and in combination was evaluated with simultaneous scored PSG recordings. Results: 215 RPE and 215 tidal breathing events were analysed. For OE, the obtained sensitivity was HR (0.703), SaO(2) (0.047), PTT (0.750), considering all three indices (0) and either of the indices (0.828) while specificity was (0.891), (0.938), (0.922), (0.953) and (0.859) respectively. For CE, the sensitivity was HR (0.715), SaO(2) (0.278), PTT (0.662), considering all indices (0.040) and either of the indices (0.868) while specificity was (0.815), (0.954), (0.901), (0.960) and (0.762) accordingly. Conclusions: Preliminary findings herein suggest that the later combination of these non-invasive indices to be a promising screening method of SDB in children.

Motivations for second position: Evidence from North-Central Australia

It has long been observed that many languages from all over the world require that certain grammatical categories (e.g., person, number, tense, modality) occur in the "second position" of a clause. Much of the research into second position has developed formal explanations for this recurring pattern, based on interactions between morphosyntax and phonology. In this article I explore how pragmatics of information packaging interacts with these other features in the development of such morphosyntactic architecture in three North-Central Australian languages: Warlpiri, Wambaya, and Garrwa.

High fidelity radiation pattern measurement system for small antennas

The paper describes a high fidelity system for measuring a radiation pattern of an electrically small antenna. In this system, the Antenna Under Test (AUT) equipped with a battery powered signal generator is suspended by a dielectric foam in the centre of a pair of dielectric rings that are supported by a pedestal of a spherical positioning mechanical sub-system. Radiation patterns are obtained directly in spherical format using a suitably constructed probe antenna of linear or circular polarization. Measurements are controlled by a computer, which also stores and processes the measured data. The results reveal considerable differences between the radiation patterns of a small antenna obtained using the proposed wireless approach and the conventional one, in which the antenna is connected with a cable to the receiver.

Movements of feral camels in central Australia determined by satellite telemetry

Movements of two female one-humped camels in central Australia were tracked using satellite telemetry between March 1986 and July 1987. During that time both animals travelled a minimum distance of over 1000 km within a radius of 125 km for one animal, and 200 km for the other. However, their movements were uite punctuated and both animals spent periods of up to several months in rleatively small areas before moving over longer distances to new areas. Both camels moved at greater rates overnight. An activity index, probably measuring feeding rate, declined during the study period for both animals. Patchy and sporadic rainfall may explain some of these results.

Central Cardiovascular Anatomy and Function in Crocodilia

Abstract: Among the vertebrates, crocodilians have the most complex anatomy of the heart and outflow channels. Their cardiovascular anatomy may also be the most func­tionally sophisticated, combining as it does the best features of both reptilian and mammalian (and avian) systems. The puzzlingly complex "plumbing" of crocodilians has fascinated ana­tomists and physiologists for a very long time, the first paper being that by Panizza (1833). Gradually, with the application of successive techniques of investigation as they became available, its functional significance has become reasonably clear, and the complexity is now revealed as a cardiovascular system of considerable elegance. In this paper I will review the main anatomical features of the heart and outflow channels, discuss what is known about the way they work, and speculate about the probable functional significance.

Central and peripheral mediation of human force sensation following eccentric or concentric contractions

Fatigue was induced in the triceps brachii of the experimental arm by a regimen of either eccentric or concentric muscle actions. Estimates of force were assessed using a contralateral limb-matching procedure, in which target force levels (25 %, 50 % or 75 % of maximum) were defined by the unfatigued control arm. Maximum isometric force-generating capacity was reduced by 31 % immediately following eccentric contractions, and remained depressed at 24 (25 %) and 48 h (13 %) post-exercise. A less marked reduction (8.3 %) was observed immediately following concentric contractions. Those participants who performed prior eccentric contractions, consistently (at all force levels), and persistently (throughout the recovery period), overestimated the level of force applied by the experimental arm. In other words, they believed that they were generating more force than they actually achieved. When the forces applied by the experimental and the control arm, were each expressed as a proportion of the maximum force that could be attained at that time, the estimates matched extremely closely. This outcome is that which would be expected if the estimates of force were based on a sense of effort. Following eccentric exercise, the amplitude of the EMG activity recorded from the experimental arm was substantially greater than that recorded from the control arm. Cortically evoked potentials recorded from the triceps brachii (and extensor carpi radialis) of the experimental arm were also substantially larger than those elicited prior to exercise. The sense of effort was evidently not based upon a corollary of the central motor command. Rather, the relationship between the sense of effort and the motor command appears to have been altered as a result of the fatiguing eccentric contractions. It is proposed that the sense of effort is associated with activity in neural centres upstream of the motor cortex.

Increased apoptosis of T lymphocytes and macrophages in the central and peripheral nervous systems of Lewis rats with experimental autoimmune encephalomyelitis treated with dexamethasone

Using light and electron microscopic histological and immunocytochemical techniques, we investigated the effects of the glucocorticoid dexamethasone on T cell and macrophage apoptosis in the central nervous system (CNS) and peripheral nervous system (PNS) of Lewis rats with acute experimental autoimmune encephalomyelitis (EAE) induced with myelin basic protein (MBP). A single subcutaneous injection of dexamethasone markedly augmented T cell and macrophage apoptosis in the CNS and PNS and microglial apoptosis in the CNS within 6 hours (h). Pre-embedding immunolabeling revealed that dexamethasone increased the number of apoptotic CD5+ cells (T cells or activated B cells), αβ T cells, and CD11b+ cells (macrophages/microglia) in the meninges, perivascular spaces, and CNS parenchyma. The induction of increased apoptosis was dose-dependent. Daily dexamethasone treatment suppressed the neurological signs of EAE. However, the daily injection of a dose of dexamethasone (0.25 mg/kg). which, after a single dose, did not induce increased apoptosis in the CNS or PNS, was as effective in inhibiting the neurological signs of EAE as the high dose (4 mg/kg), which induced a marked increase in apoptosis. This indicates that the beneficial clinical effect of glucocorticoid therapy in EAE does not depend on the induction of increased apoptosis. The daily administration of dexamethasone for 5 days induced a relapse that commenced 5 days after cessation of treatment, with the severity of the relapse tending to increase with dexamethasone dosage.