Herbaceous species diversity in relation to fire severity in Zagros oak forests,Iran     

Morteza Pourreza  Seyed Mohsen Hosseini  Ali Akbar Safari Sinegani  Mohammad Matinizadeh  Seyed Jalil Alavai 《林业研究》2014,25(1):113-120

Zagros forests are mainly covered byQuercus brantii L. coppices and oak sprout clumps occupy the forest area like patches. We investigated post-fire herbaceous diversity in the first growing season after fire. For this purpose neighboring burned and unburned areas were selected with the same plant species and ecological conditions. The data were collected from areas subjected to different fire severities. Overall 6 treatments were considered with respect to fire severity and the mi-crosites of inside and outside of oak sprout clumps including： unburned inside and outside of sprout clumps （Ni and No）, inside of sprout clumps that burned with high fire severity （H）, inside of sprout clumps that burned with moderate fire severity （M）, outside of sprout clumps that burned with low fire severity （OH and OM）. Different herbaceous com-position was observed in the unburned inside and outside of oak sprout clumps. The species diversity and richness were increased in treatments burned with low and moderate fire severity. However, in treatment burned with high fire severity （H）, herbaceous cover was reduced, even-ness was increased, and richness and diversity were not significantly changed. We concluded that besides the microsites conditions in forest, fire severity is an inseparable part of the ecological effect of fire on her-baceous composition.  相似文献   

Gastritis and gastric perforation due to Habronema spp. in the horse     

M.Gh. Nadalian  S.H. Hosseini  A. Tavassoli  A. Raoufi 《Journal of Equine Veterinary Science》1997,17(7):385-386

A three-year-old horse was admitted to the Tehran Veterinary faculty teaching hospital with colic symptoms. The horse died with severe pain after two hours. Necropsy findings revealed a heavy worm infestation in the stomach. Parasitological examinations identified massive in vasion of Habronema muscae on the stomach mucosal surface and Draschia megastoma in the deep layer of mucosa and muscles.Histopathological sections showed two separate lesions including diffuse infiltration of mononuclear inflammatory cells with a number of eosinophils in the mucosa and submucosa that suggested eosinophilic gastritis. Another finding was a large granulation mass in the deep layer of the submucosa that contained granulomatous necrotic tissue and cross sections of D. megastoma.  相似文献   

Imaging of intermittency in ripple-wave turbulence     

WB Wright  R Budakian  DJ Pine  SJ Putterman 《Science (New York, N.Y.)》1997,278(5343):1609-1612

The dynamics of a fluid surface filled with high-amplitude ripples were studied with a technique (diffusing light photography) that resolves the height at all locations instantaneously. Even when nonlinearities are strong enough to generate a (Kolmogorov) cascade from long wavelength (where energy is input) to shorter wavelength, the resulting turbulent state contains large coherent spatial structures. The appearance of these structures in a thermal equilibrium state (with the same average energy) would be highly improbable.  相似文献   

Evaluation of a regimen using a progesterone releasing intravaginal device (CIDR) and PMSG as a treatment for post partum anoestrus in dairy cattle     

TF. JUBB  P. BRIGHTLING  J. MALMO†  MT. LARCOMBE  GA. ANDERSON  SJ. HIDES‡ 《Australian veterinary journal》1989,66(10):334-336

Anoestrous dairy cows in seasonally calving herds in the Macalister Irrigation District of Gippsland, Victoria were treated at the start of the mating period with a progesterone releasing intravaginal device (CIDR). The CIDR was inserted for 7 days and 400 IU of PMSG was injected intramuscularly at removal. There was no clinically useful difference among cows receiving the CIDR, a placebo and untreated cows in the interval from treatment to either first oestrus or conception, the conception rate to first service or percent pregnant by the end of mating. Analyses of data from 2-year-old cows, older cattle, cows calved at least 45 days or cows calved at least 55 days and cows treated 3 weeks after the start of mating did not show improved reproductive performance following treatment with the CIDR.  相似文献   

An attempt to prevent acute toxoplasmosis in macropods by vaccination with Hammondia hammondi     

GL REDDACLIFF  SJ PARKER  JP DUBEY  PJ NICHOLLS  AM JOHNSON  DW COOPER 《Australian veterinary journal》1993,70(1):33-35

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Assessment of tetracycline and Babesia culture supernatant as prophylactics for moderating reactions in cattle to live Babesia and Anaplasma vaccines     

WK JORGENSEN  RE BOCK  TG KINGSTON  AJ DE VOS  SJ WALDRON 《Australian veterinary journal》1993,70(1):35-36

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Effects of limited concentrate feeding on growth and blood and serum variables, and on nutrient digestibility and gene expression of hepatic gluconeogenic enzymes in dairy calves     

Lohakare JD  van de Sand H  Gerlach K  Hosseini A  Mielenz M  Sauerwein H  Pries M  Südekum KH 《Journal of animal physiology and animal nutrition》2012,96(1):25-36

This study elucidated the effects of limited concentrate feeding on growth, nutrient digestibility, blood profile and gene expression of gluconeogenic enzymes in the liver of dairy calves. The study utilized 36 German Holstein dairy calves (5-7 days of age) divided into two groups of 18 calves each for 150 days. Control group calves received 2 kg/(calf × day) of concentrate, whereas calves in the restricted group received only 1 kg/(calf × day). Good quality forage (mixture of maize and grass silages) was available for ad libitum consumption to both groups. The intake of milk replacer before weaning, and of concentrate were recorded daily per calf; however, the consumption of forages was quantified as daily average of the group. Body weights (BW) were recorded at start and on days 35, 70, 112 and 150. Blood and serum samples and spot urinary and faecal samples were also collected at similar time points. On days 70 and 150, liver biopsies were collected from seven animals in each group. The BW was not different between the groups at all times. Total BW gain in the control group was 124 kg as opposed to 111 kg in restricted group that led to average BW gain of 827 g/day and 739 g/day in respective groups, and the differences were significant (p = 0.018). As planned, the control group had higher concentrate and lower forage intake than the restricted group. The blood haemoglobin, haematocrit and serum variables (glucose, total protein, albumin and urea) were within the normal range in both groups, but serum glucose was higher (p < 0.05) in control than in restricted group at 70 days. There was no difference between groups in organic matter (OM) digestibility which declined (p < 0.001) with increasing age in both groups. Microbial crude protein (MCP) synthesis estimated from urinary allantoin excretion increased (p < 0.001) in both groups with increasing age but was not different between groups. The mRNA expressions for the gluconeogenic enzymes, cytosolic and mitochondrial phosphoenol pyruvate carboxykinase (EC 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1) measured by quantitative real-time PCR in liver biopsies showed no differences between groups. Overall, restricting concentrate moderately reduced the growth intensity without affecting the normal serum and blood indices, and MCP synthesis and OM digestibility showed no differences between groups, indicating that both concentrate feeding schemes can be successfully applied.  相似文献   

Echinococcosis/hydatidosis in western Iran     

Dalimi A  Motamedi G  Hosseini M  Mohammadian B  Malaki H  Ghamari Z  Ghaffari Far F 《Veterinary parasitology》2002,105(2):161-171

In the present study, 115 stray dogs (56 males and 59 females, mixed breed), 86 golden jackal (Canis aureus, 42 males and 44 females), 60 red foxes (Vulpes vulpes, 33 males and 27 females), and three female wolves (Canis lupus) were examined for Echinococcus granulosus infection, as well as, 32,898 sheep, 10,691 goats, 15,779 cattle and 659 buffaloes for hydatid infection from five provinces in western Iran during 3 years (1997-2000). Meanwhile fertility rates of different types and forms of cysts isolated from infected animals and the viability of protoscolices were also determined. Results indicated that 19.1% of the dogs, 2.3% of the golden jackals and 5% of the red foxes were infected with Echinococcus granulosus. 11.1% of the sheep, 6.3% of the goats, 16.4% of the cattle and 12.4% of the buffaloes were also found to be infected with hydatid cyst. The cysts isolated from liver and lungs of the sheep show higher fertility rate than the cysts of liver and lungs of goats, cattle and buffaloes.  相似文献   

A novel method for manufacturing nanofibers     

A. Valipouri  S. A. Hosseini Ravandi  A. R. Pishevar 《Fibers and Polymers》2013,14(6):941-949

This study presents a method for the fabrication of ultrafine polymeric nanobers utilizing centrifugal and electrostatic forces simultaneously. To reduce the diameter and variability of nanofibers produced from polyacrylonitrile (PAN) and poly-L-lactic acid (PLLA), a unique electro-centrifuge spinning device was designed using rotating nozzle and collector, whereas the fabrication process (spinning head) was skillfully sealed from ambient airflow. The polymer solution was continuously delivered by a rotating nozzle and the nanofibers were collected by a rotating cylindrical collector at the same rotational speed as the nozzle. Field emission scanning electron microscope (FESEM) results demonstrated that this method has a significant effect on the quality and fineness of nanofibers. The diameters of nanobers were controlled by adjusting the rotation speed of spinning head. The effect of the rotation speed on the morphology of the nanofibers fabricated by this device was also evaluated. In order to provide a useful context for the current nanofiber production method, nanofibers obtained in this method were compared with those produced by other methods. The results show that air-sealedcentrifuge-electrospinning system (ASCES) is a facile method for the fabrication nanobers with smaller diameters and high uniform structures.  相似文献   

Microstructure of heat-treated PAN nanofibers     

M. Sadrjahani  S. A. Hosseini Ravandi 《Fibers and Polymers》2013,14(8):1276-1282

A simple and modified electrospinning technique was utilized to prepare aligned and heat treated Polyacrylonitrile nanofibers by using a rotating drum fixed on top of syringe needles and applying upward hot air flow which can facilitate to heat nanofibers in electrospinning zone. Polyacrylonitrile nanofibers were electrospun from its 14 wt% solution in dimethylformamide under practical conditions. Angular power spectrum analysis showed better fiber alignment with increasing take up speed, although SEM studies demonstrated wider diameters of nanofibers being produced by modified method. The glass transition temperature of all prepared samples were determined between 70 °C and 90 °C using DSC technique. The Quantitative analysis of WAXD patterns has revealed the positive effect of modified method on the degree of crystallization of nanofibers heat treated at higher take up speed. The maximum chain orientation factor of 0.27 was determined for nanofibers collected at linear velocity of 114.5 m/min in the modified set up using Raman Spectroscopy technique.  相似文献