90 years of forest cover change in an urbanizing watershed: spatial and temporal dynamics

Landscape structure in the Eastern US experienced great changes in the last century with the expansion of forest cover into abandoned agricultural land and the clearing of secondary forest cover for urban development. In this paper, the spatial and temporal patterns of forest cover from 1914 to 2004 in the Gwynns Falls watershed in Baltimore, Maryland were quantified from historic maps and aerial photographs. Using a database of forest patches from six times—1914, 1938, 1957, 1971, 1999, and 2004—we found that forest cover changed, both temporally and spatially. While total forest area remained essentially constant, turnover in forest cover was very substantial. Less than 20% of initial forest cover remained unchanged. Forest cover became increasingly fragmented as the number, size, shape, and spatial distribution of forest patches within the watershed changed greatly. Forest patch change was also analyzed within 3-km distance bands extending from the urban core to the more suburban end of the watershed. This analysis showed that, over time, the location of high rates of forest cover change shifted from urban to suburban bands which coincides with the spatial shift of urbanization. Forest cover tended to be more stable in and near the urban center, whereas forest cover changed more in areas where urbanization was still in process. These results may have critical implications for the ecological functioning of forest patches and underscore the need to integrate multi-temporal data layers to investigate the spatial pattern of forest cover and the temporal variations of that spatial pattern.     

A high-resolution record of holocene climate change in speleothem calcite from cold water cave, northeast iowa

High-precision uranium-thorium mass spectrometric chronology and (18)O-(13)C isotopic analysis of speleothem calcite from Cold Water Cave in northeast Iowa have been used to chart mid-Holocene climate change. Significant shifts in dagger(18)O and dagger(13)C isotopic values coincide with well-documented Holocene vegetation changes. Temperature estimates based on (18)O/(16)O ratios suggest that the climate warmed rapidly by about 3 degrees C at 5900 years before present and then cooled by 4 degrees C at 3600 years before present. Initiation of a gradual increase in dagger(13)C at 5900 years before present suggests that turnover of the forest soil biomass was slow and that equilibrium with prairie vegetation was not attained by 3600 years before present.     

Prognostic Value of Various Spermatological Attributes as Predictors of Zona Binding and Zona Penetration of Buffalo (Bubalus bubalis) Semen

Twenty‐four ejaculates from six (four ejaculates each) Surti buffalo bulls aged 4–8 years were used to assess various attributes of spermatozoa influencing the zona‐binding and zona‐penetration tests. Ejaculates from each bulls were subjected to in vitro sperm‐‐zona binding and sperm‐‐zona penetration tests (four replicates per bull) using immature buffalo oocytes. The average number of spermatozoa bound per oocyte was 27.79 ± 5.90. The average number of spermatozoa penetrated per oocyte was 3.35 ± 0.64. The average number of zona‐bound and ‐penetrated spermatozoa differed significantly between animals. Significant difference (p < 0.05) was observed between the plasmalemma integrity as assessed by eosin‐‐nigrosin stain and hypo‐osmotic swelling (HOS) test. Furthermore, the percentage of cells positive for the HOS test, i.e. functional membrane integrity (51.25 ± 2.32) was significantly (p < 0.05) higher than hypo‐osmotic swelling‐Giemsa (HOS‐G) test, i.e. the subpopulation of spermatozoa positive for functional membrane and acrosomal integrities (42.87 ± 4.56). The HOS test had significant correlations with plasmalemma integrity as measured by the vital stain, eosin‐‐nigrosin (r = 0.85, p < 0.05). The HOS‐G test also had significant correlation with plasmalemma integrity measured by vital stains such as eosin‐‐nigrosin (r = 0.90, p < 0.05) and fluorogenic stains [carboxyfluorescein diacetate (CFDA) and propidium iodide (PI); r = 0.92, p < 0.01] and HOS test (r = 0.93), acrosomal integrity (r = 0.86, p < 0.05) and mitochondrial membrane potential (r = 0.99, p < 0.01). The plasmalemma integrity (fluorogenic stain), functional membrane integrity (HOS test), subpopulation of spermatozoa positive for functional membrane and acrosomal integrities (HOS‐G test) and mitochondrial membrane potential had significant (p < 0.05) correlation with sperm zona binding and penetration. The present study indicates that these parameters could represent important determinants of sperm quality influencing zona binding and penetration.     

The Importance of Having Zinc During In Vitro Maturation of Cattle Cumulus–Oocyte Complex: Role of Cumulus Cells

The aim of this study was to investigate the influence of zinc (Zn) on the health of cumulus–oocyte complex (COC) during in vitro maturation (IVM). Experiments were designed to evaluate the effect of Zn added to IVM medium on: DNA integrity, apoptosis, cumulus expansion and superoxide dismutase (SOD) activity of cumulus cells (CC). Also, role of CC on Zn transport during IVM was evaluated on oocyte developmental capacity. DNA damage and early apoptosis were higher in CC matured with 0 μg/ml Zn compared with 0.7, 1.1 and 1.5 μg/ml Zn (p < 0.05). Cumulus expansion did not show differences in COC matured with or without Zn supplementation (p > 0.05). Superoxide dismutase activity was higher in COC matured with 1.5 μg/ml Zn than with 0 μg/ml Zn (p < 0.05). Cleavage and blastocyst rates were recorded after IVM in three maturation systems: intact COCs, denuded oocytes with cumulus cells monolayer (DO + CC) and denuded oocytes (DO). Cleavage rates were similar when COC, DO + CC or DO were matured with 1.5 μg/ml Zn compared with control group (p > 0.05). Blastocyst rates were significantly higher in COC than in DO + CC and DO with the addition of 1.5 μg/ml Zn during IVM (p < 0.01). Blastocyst quality was enhanced in COC and DO + CC compared with DO when Zn was added to IVM medium (p < 0.001). The results of this study indicate that Zn supplementation to IVM medium (i) decreased DNA damage and apoptosis in CC; (ii) increased SOD activity in CC; (iii) did not modify cumulus expansion and cleavage rates after in vitro fertilization; (iv) improved subsequent embryo development up to blastocyst stage; and (v) enhanced blastocyst quality when CC were present either in intact COC or in coculture during IVM.     

Effects of tramadol,morphine or their combination in dogs undergoing ovariohysterectomy on peri-operative electroencephalographic responses and post-operative pain

Abstract

AIM: To compare the peri-operative electroencephalogram (EEG) responses and post-operative analgesic efficacy of pre-operative morphine or tramadol with a combination of low-dose pre-operative morphine and post-operative tramadol, in dogs undergoing ovariohysterectomy.

METHODS: Dogs undergoing routine ovariohysterectomy were treated with either pre-operative morphine (0.5 mg/kg S/C, n=8), or tramadol (3 mg/kg S/C, n=8), or pre-operative low-dose morphine (0.1 mg/kg S/C) and post-operative tramadol (3 mg/kg I/V, n=8). All dogs received routine pre-anaesthetic medication, and anaesthesia was induced with I/V thiopentone to effect and maintained with halothane in oxygen. Respiratory rate, heart rate, end-tidal halothane tension (EtHal) and end-tidal CO₂ tension (EtCO₂) were monitored throughout surgery. The EEG was recorded continuously in a three electrode montage. Median frequency (F50), total power (Ptot) and 95% spectral edge frequency (F95) of the EEG power spectra were compared during different 100-second periods of surgery: prior to and during skin incision, ligation of each ovarian pedicle, ligation of uterine body and skin closure. Post-operatively, pain was assessed using the short form of the Glasgow composite measure pain scale (CMPS-SF).

RESULTS: There was no difference in F50 or Ptot of the EEG between baseline and noxious surgical events within each treatment group, or between the three groups (p>0.05). The mean F95 was higher during the first three periods of surgery for dogs administered tramadol and low-dose morphine than those that received 0.5 mg/kg morphine (p=0.001). Dogs that received low-dose morphine and tramadol had lower CMPS-SF pain scores after ovariohysterectomy than those that received either tramadol or morphine alone (p=0.001). There was no difference in pain scores between dogs in the latter two groups.

CONCLUSION AND CLINICAL RELEVANCE: Tramadol and morphine administered pre-operatively provided an equal degree of post-operative analgesia in dogs after ovariohysterectomy. A combination of pre-operative low-dose morphine and post-operative tramadol produced better post-operative analgesia than either drug administered alone pre-operatively. Administration of analgesics pre- and post-operatively could result in improved post-operative well-being of ovariohysterectomised dogs.     

Risk characterisation and management of sewage sludge on agricultural land-implications for the environment and the food-chain

The disposal of sewage wastes may cause severe environmental problems as was graphically demonstrated with pollution on Sydney's ocean beaches in recent years. Sewage sludges contain valuable plant nutrients and organic matter which can improve the fertility and structure of the soil. However, human parasites, pathogenic micro-organisms and chemicals capable of causing soil contamination, phytotoxicity and residues in animal products may also be present. Although sewage sludge is frequently spread on agricultural land overseas, it is not common in Australia and most states do not have specific regulations to minimise risk and promote good practice. A sludge-to-land program began in the Sydney region in 1990. It follows guidelines written by NSW Agriculture to encourage beneficial agricultural use of sludge by adoption of environmentally sustainable practices. This article describes the major risks to the food-chain and the environment, which may be associated with applying sewage sludge to agricultural land. It summarises how the risks are managed, and where further research data are required.