Bashir Ahmed - Academia.edu (original) (raw)

Papers by Bashir Ahmed

Journal of Civil Engineering and Construction Technology, Jan 31, 2011

In developing countries, like Bangladesh, priority to upgrade a national highway is mainly based ... more In developing countries, like Bangladesh, priority to upgrade a national highway is mainly based on technical aspects like daily traffic demands; whereas due consideration to economic factors is generally neglected. Based on a few parameters, if highways are rated keeping in mind some social economic attributes, significant contribution to our infrastructure-based economy could be made. Socioeconomic parameters are also considered as determining factors to relevant infrastructure implementation. Combination of socio-parameters, such as social viability, accident rate with technical parameters like daily demand, and amount of axle loads will offer sound retrospective of the exiting road systems. The objective of the present paper is to develop a rating system for prioritization of highways using discrete multi-criteria analysis.

Journal of Civil Engineering and Construction Technology, Nov 30, 2011

Traffic is a major problem in Manchester, UK. Various methods had been considered by the local au... more Traffic is a major problem in Manchester, UK. Various methods had been considered by the local authority to cut vehicle numbers, congestion charging was widely viewed as being amongst the most effective. The widely perceived success of the London congestion pricing scheme also led Manchester to follow suit. Legislation permits British cities to introduce road pricing schemes, although they require approval of a higher authority to implement their proposals. A weekday, directional, peak-time only congestion charging scheme to tackle congestion at the time and in the place and direction where it is at its worst was considered in Greater Manchester from 2013. However, in a local referendum in 2008, the citizens of Manchester rejected the proposed congestion charging scheme. This study examines the feasibility of the proposed scheme, potential benefits through case studies of similar schemes around the world, and tries to explore the reasons of public unacceptability.

Calcium, carbonate, bicarbonate and dissolved organic carbon levels of water, clay type and conte... more Calcium, carbonate, bicarbonate and dissolved organic carbon levels of water, clay type and content of sediment were taken into consideration for studying their influence in modifying the toxicity of Basathrin (cypermethrin 25% EC). It was observed that when calcium was included with the water medium at different concentrations, toxicity of Cypermethrin was not altered. Reduced toxicity was observed when the carbonate and bicarbonate level of water was increased. But higher carbonate or bicarbonate concentration was not favourable. When dissolved organic carbon was included with the water medium at different concentrations, toxicity of cypermethrin was found to decrease. Both clay type and content influenced the toxicity of cypermethrin. Kaolinite was able to decrease the toxicity but the effect was more pronounced in case of Bentonite clay. Sublethal tests with fingerlings of common carp for different biochemical parameters e.g. liver glycogen, serum glucose, total protein, alkalin...

Anesthesia: Essays and Researches, 2012

This study aims to compare relative efficacy of three different doses of intrathecal bupivacaine ... more This study aims to compare relative efficacy of three different doses of intrathecal bupivacaine in combined spinal epidural anaesthesia (CSEA) for caesarean delivery. In a double blinded manner, 204 cases were randomized into three groups: I, II, and III to receive a dose of 4, 5.5, and 7 mg of hyperbaric bupivacaine with a fixed dose of 25 μg fentanyl intrathecally, and Dextran 40 w/v 10 mL given for epidural volume extension (EVE), in CSEA. Our primary outcome was the number of effective doses. The block characteristics and side effects were also monitored. Out of 198 patients completing the study, 53, 63, and 65 in group I, II and III had effective doses. Mean Pi (probability of an effective dose) in group I, II, and III, was 0.81, 0.95, and 0.97, respectively. The Pb (superiority of one group over the other) of group II and III was higher than group I. The maximal sensory block height in group II and III (T2) was higher than group I (T3), with a shorter time required to achieve the same. Group I and II exhibited lesser motor blockade, lesser hypotension with early recovery as compared to group III. No significant adverse effects were observed between the groups. The intermediate dose of bupivacaine (5.5 mg) provided safe and effective anaesthesia for caesarean delivery with an additional advantage of lesser episodes of hypotension and partial motor blockade in CSEA.

Journal of the College of Physicians and Surgeons--Pakistan : JCPSP, 2004

To emphasize the role and importance of multidisciplinary approach in the management of oral cavi... more To emphasize the role and importance of multidisciplinary approach in the management of oral cavity cancers involving the mandible. Descriptive study. The Departments of Plastic and Reconstructive Surgery, ENT / Head and Neck Surgery and Radiation Oncology, Combined Military Hospital, Rawalpindi. Duration spans over a period of six years. A total of 63 patients who had biopsy-proven oromandibular tumors, after thorough assessment / staging in Joint Head and Neck Oncology Clinic, underwent resection and reconstruction for malignant oral cavity tumors involving the mandible were included in the study. All the resected tumor specimen were sent for histopathology. All the post-resection defects were properly classified and reconstructed by the plastic surgery team. Postoperatively, all the patients underwent adjuvant full dose radiotherapy at the Department of Radiation Oncology. Complications were recorded and managed accordingly. At one year follow-up all the available patients were a...

Journal of the College of Physicians and Surgeons--Pakistan : JCPSP, 2005

... 2005 Sep;15(9):583-4. Microbiology of ear discharge in Quetta. Ahmed B, Hydri AS, Ejaz A, Far... more ... 2005 Sep;15(9):583-4. Microbiology of ear discharge in Quetta. Ahmed B, Hydri AS, Ejaz A, Farooq S, Zaidi SK, Afridi AA. Department of ENT/Head and Neck Surgery, Combined Military Hospital, Quetta, Pakistan. PMID: 16181588 [PubMed - indexed for MEDLINE]. ...

European Urology Supplements, 2013

Introduction & Objectives: Non contrast computed tomography (NCCT), is currently the preferred me... more Introduction & Objectives: Non contrast computed tomography (NCCT), is currently the preferred method of investigating the suspected renal colic. One of its advantages being able to determine the stone composition by measuring attenuation values in Hounsefield unit (HU) and Hounsefield unit density (HUD). However, there are contradictory findings in the literature. Predicting stone composition is considered as an important prognostic factor especially when subjecting a child with renal stone for ESWL. Stone composition and its fragility is complex and highly variable in different regions of the world. The aim of the study is to assess the stone composition on non-contrast computed tomography (NCCT) on the basis of attenuation values in Hounsfield unit (HU) in our paediatric stone population. Material & Methods: This is a retrospective comparison of 94 renal stones in children managed between 2009 and 2012 who underwent preoperative NCCT using a standard protocol. Mean attenuation values in HU were determined by measuring them at three points of each stone and HU density (HU/size) were calculated. Post operative stone composition analysis was done by Infra Red Spectroscopy (FTIR). HU values of various stone compositions were compared and statistically analyzed. Results: The mean age of the patients was 5.6 years±3.36 years with M:F ratio of 1.6:1. Of 94 stones, 51 (54%) were pure stones and 43 (46%) were mixed. Among pure stones 21 were Ammonium Hydrogen Urate (AHU), mean HU 459±81.07 were Uric Acid (UA), mean HU 469±44.07 were xanthine, mean HU 390±65.10 were COM, mean HU 1289±288 and 3 cystine, mean HU 574±182. Of the mixed stones, 7 were AHU+COM and 5 were COM+AHU, mean HU 595±181 and 828±240 respectively. Other mixed stones were AHU+UA, UA+AHU, COM+CaPO4, CaPO4+AHU and others. A significant difference was identified among HU values of the COM and urate stones (UA, AHU and xanthine) p ≤ 0.0001. It was also observed that in some mixtures HU and HUD increases with the increasing calcium component (AHU + COM (minor) HU 595±181, AHU + COM (major) HU 828±240), and HU also increased with the size of stones for all types of composition. Conclusions: Determining stone attenuation (HU) values on NCCT is a useful parameter to differentiate between COM and urate stones. This may be helpful in the choice of effective treatment modality.

European Urology Supplements, 2013

Introduction & Objectives: Extracorporeal shockwave lithotripsy (ESWL) is the first line of treat... more Introduction & Objectives: Extracorporeal shockwave lithotripsy (ESWL) is the first line of treatment for renal stone in children. However, the outcome is variable and depends on multiple factors including stone size and stone density (composition). When ultrasound KUB and plain X-rays are inconclusive because of various reasons, non contrast computed tomography (NCCT) is an important imaging investigation when stone size and stone density can be assessed with better accuracy and can be useful in predicting the outcome post ESWL. With this background we analyzed the ESWL outcome in our children on the basis of stone density in Hounsfield unit (HU) and stone size on NCCT. Material & Methods: This is a retrospective analysis of 61 renal stones in children treated with ESWL under General Anaesthesia, who had non contrast computed tomography (NCCT) prior to ESWL. Their records were reviewed for demography, stone density in Hounsefield unit (HU) on NCCT, stone size, number of ESWL sessions and outcome. On the basis of stone density they were categorized into ≤400 HU, 400-700 HU and >700 HU and stone size 0.5-1.0 cm and >1.0 cm. An ultrasound KUB and X-ray KUB (when indicated) were done at 4 weeks and 3 months after each session to categorize patients as stone free (success) and residual fragment after 2 sessions were considered as failure. Results: The mean age of the patient was 5.9±4.3 years with M: F ratio of 3:1. The mean stone size was 1.0±0.33 cms. Of 61 renal stones 13 were ≤400 HU, 21, 400-700 HU and 27, >700 HU. Stone clearance after single session of ESWL for 0.5-1.0 cms was 100% for ≤400 HU, 78.5% for 400-700 HU and 75% for >700 HU. Among >1.0 cm stones, the outcome was 60% for ≤400 HU, 43% for 400-700 HU and 36.3% for >700 HU. Of the failure after 2 sessions 6% were 0.5-1.0 cms (>700HU) and for >1.0 cm stone 20%, 28.5% and 36.3% for HU ≤400, 400-700 and >700 respectively. Conclusions: Our results shows that both stone density and stone size affect the ESWL outcome and they are independent variables, therefore NCCT can be a useful investigation in predicting the outcome post ESWL.

Research Journal of Finance …, 2011

The purpose of this study is to examine the impact of top management ethical behavior on job sati... more The purpose of this study is to examine the impact of top management ethical behavior on job satisfaction of banks employees in Pakistan. Data was collected through questionnaire survey from 120 employees Random sampling method was used so that to ...

The Journal of Physiology, 2006

The responses of neurons within the primary auditory cortex (A1) of the ferret elicited by broadb... more The responses of neurons within the primary auditory cortex (A1) of the ferret elicited by broadband dynamic spectral ripple stimuli were examined over a range of ripple spectral densities and ripple velocities. The large majority of neurons showed modulated responses to these stimuli and responded most strongly at low ripple densities and velocities. The period histograms of their responses were subjected to Fourier analysis, and the ratio of the magnitudes of the f 1 and f 0 (DC) components of these responses were calculated to give a quantitative index of response linearity. For 82 out of 396 neurons tested (20.7%) this ratio remained above 1.0 over the entire range of ripple densities and velocities. These neurons were classified as 'consistently linear'. A further 134/396 (33.8%) of neurons maintained an f 1 /f 0 ratio above 1.0 for either a range of ripple densities at a fixed ripple velocity, or over a range of ripple velocities at a specific ripple density, and were classified as 'locally linear'. Interestingly, for the superficial layers of the primary auditory cortex, consistently linear and locally linear neurons outnumbered nonlinear neurons by a 2:1 ratio. The converse was true for the deep layers. Unlike in primary visual cortex, where f 1 /f 0 ratios have been reported to exhibit a bimodal distribution with a minimum at f 1 / f 0 ≈ 1, f 1 /f 0 ratios for A1 are unimodally distributed with a peak at f 1 / f 0 ≈ 1.

Journal of Neuroscience, 2006

It has been suggested that "call-selective" neurons may play an important role in the encoding of... more It has been suggested that "call-selective" neurons may play an important role in the encoding of vocalizations in primary auditory cortex (A1). For example, marmoset A1 neurons often respond more vigorously to natural than to time-reversed twitter calls, although the spectral energy distribution in the natural and time-reversed signals is the same. Neurons recorded in cat A1, in contrast, showed no such selectivity for natural marmoset calls. To investigate whether call selectivity in A1 can arise purely as a result of auditory experience, we recorded responses to marmoset calls in A1 of naive ferrets, as well as in ferrets that had been trained to recognize these natural marmoset calls. We found that training did not induce call selectivity for the trained vocalizations in A1. However, although ferret A1 neurons were not call selective, they efficiently represented the vocalizations through temporal pattern codes, and trained animals recognized marmoset twitters with a high degree of accuracy. These temporal patterns needed to be analyzed at timescales of 10-50 ms to ensure efficient decoding. Training led to a substantial increase in the amount of information transmitted by these temporal discharge patterns, but the fundamental nature of the temporal pattern code remained unaltered. These results emphasize the importance of temporal discharge patterns and cast doubt on the functional significance of call-selective neurons in the processing of animal communication sounds at the level of A1.

Separation Science and Technology, 1992

Abstract A Hf transport study through supported liquid membranes has been carried out to determin... more Abstract A Hf transport study through supported liquid membranes has been carried out to determine flux and permeability data for this metal ion. Tri-n-butyl phosphate (TBP)-xylene-based liquid membranes supported in polypropylene hydrophobic microporous film have ...

Proceedings of the National Academy of Sciences, 2006

Despite the lack of direct evidence, it is generally believed that top-down signals are mediated ... more Despite the lack of direct evidence, it is generally believed that top-down signals are mediated by the abundant feedback connections from higher- to lower-order sensory areas. Here we provide direct evidence for a top-down mechanism. We stained the visual cortex of the ferret with a voltage-sensitive dye and presented a short-duration contrast square. This elicited an initial feedforward and lateral spreading depolarization at the square representation in areas 17 and 18. After a delay, a broad feedback wave (FBW) of neuron peak depolarization traveled from areas 21 and 19 toward areas 18 and 17. In areas 18 and 17, the FBW contributed the peak depolarization of dendrites of the neurons representing the square, after which the neurons decreased their depolarization and firing. Thereafter, the peak depolarization surrounded the figure representation over most of areas 17 and 18 representing the background. Thus, the FBW is an example of a well behaved long-range communication from h...

NeuroReport, 2000

Centre and the McDonnell-Pew Centre for Cognitive Neuroscience are acknowledged. The experimental... more Centre and the McDonnell-Pew Centre for Cognitive Neuroscience are acknowledged. The experimental work was undertaken whilst B.A. was an MRC Senior Scientist at the Anatomical Neuropharmacology Unit, University of Oxford. I would like to thank Professors K.A.C Martin, A.D Smith, and P. Somogyi for facilities provided. A synchronizing volley of excitation was delivered to cells from the primary visual cortex of the anaesthetized cat by an electrical pulse stimulation of the optic radiations. In intracellular records, this resulted in an initial, fast depolarization of the membrane potential followed by a longer lasting (266 ms) hyperpolarization, and then to small amplitude damped oscillations of the membrane potential. In different cells the number of peaks ranged from 3 to 6, and the amplitude of the ®rst oscillation averaged 3.5 mV. If the pulse stimulation was repeated during visual drive with an optimal bar stimulus, the membrane potential¯uctuations were non-linearly enhanced with spike bursts recorded during the depolarized states of the membrane potential. The amplitude of the ®rst oscillation in these cases averaged 6.9 mV. The mean frequency of damped oscillations was 9.9 Hz. The results suggest that these oscillations are mediated by the waxing and waning of the excitatory drive to the recorded neurone. NeuroReport 11:1243±1247 &

Journal of Regional Science, 1990

Factors affecting regional differences in population growth in the United States are explored. &a... more Factors affecting regional differences in population growth in the United States are explored. &amp;quot;In this study, we estimated the contributions of births, deaths, and migration to changes in population size between 1950 and 1980 for the 48 contiguous states in the United States. We found that population momentum (i.e., the growth that would occur in a closed population if fertility and mortality rates remained constant) had the largest effect on population growth in most states, but that differences in net migration were the major cause of state-to-state differences in growth rates. We also found that net migration has been gaining in importance compared to natural increase as a component of population growth. We expect this trend to continue in coming decades.&amp;quot; This is a revised version of a paper originally presented at the 1988 Annual Meeting of the Population Association of America (see Population Index, Vol. 54, No. 3, Fall 1988, p. 429).

Journal of Pediatric Urology, 2009

inserted prior or during the procedure; A nephrostomy, a double pigtail ureteral stent, or an ext... more inserted prior or during the procedure; A nephrostomy, a double pigtail ureteral stent, or an externalized ureteral catheter were inserted in 6 (14%), 9 (22%), and 23 (63%) patients respectively. All ureteral catheters were removed at the end of the procedure. 3SFR was 78%, and 13 patients (22%) required an additional procedure with subsequent total 96.5% and 98.3% SFR after a 2nd and a 3rd ESWL. SFR was not dependent on patients' age, stone location (proximal, mid or distal), or stone size.

Journal of Pediatric Urology, 2008

Twenty four hours urinary and stat urine samples were collected from 66 patients with Calcium Oxa... more Twenty four hours urinary and stat urine samples were collected from 66 patients with Calcium Oxalate stones before and one month after stone removal with dietary and medical interventions. BRI was estimated in 2 ml of native urine at 37 °C. Ammonium Oxalate 40 ...

Journal of Pediatric Urology, 2008

We retrospectively reviewed the records of children who underwent PCNL procedures for renal calcu... more We retrospectively reviewed the records of children who underwent PCNL procedures for renal calculi from 2004 to 2007 A total of 300 children with renal calculi were treated with PCNL. Patient&amp;#x27;s age at operation ranged from 8 months to 15 years. Patients had pre-operative blood and ...

Journal of Neurophysiology, 2008

We used optical imaging of intrinsic signals to study the large-scale organization of ferret audi... more We used optical imaging of intrinsic signals to study the large-scale organization of ferret auditory cortex in response to complex sounds. Cortical responses were collected during continuous stimulation by sequences of sounds with varying frequency, period, or interaural level differences. We used a set of stimuli that differ in spectral structure, but have the same periodicity and therefore evoke the same pitch percept (click trains, sinusoidally amplitude modulated tones, and iterated ripple noise). These stimuli failed to reveal a consistent periodotopic map across the auditory fields imaged. Rather, gradients of period sensitivity differed for the different types of periodic stimuli. Binaural interactions were studied both with single contralateral, ipsilateral, and diotic broadband noise bursts and with sequences of broadband noise bursts with varying level presented contralaterally, ipsilaterally, or in opposite phase to both ears. Contralateral responses were generally large...

Journal of Neurophysiology, 2004

We have adapted a new approach for intrinsic optical imaging, in which images were acquired conti... more We have adapted a new approach for intrinsic optical imaging, in which images were acquired continuously while stimuli were delivered in a series of continually repeated sequences, to provide the first demonstration of the large-scale tonotopic organization of both primary and nonprimary areas of the ferret auditory cortex. Optical responses were collected during continuous stimulation by repeated sequences of sounds with varying frequency. The optical signal was averaged as a function of time during the sequence, to produce reflectance modulation functions (RMFs). We examined the stability and properties of the RMFs and show that their zero-crossing points provide the best temporal reference points for quantifying the relationship between the stimulus parameter values and optical responses. Sequences of different duration and direction of frequency change gave rise to comparable results, although in some cases discrepancies were observed, mostly between upward- and downward-frequen...

Journal of Civil Engineering and Construction Technology, Jan 31, 2011

Journal of Civil Engineering and Construction Technology, Nov 30, 2011

Anesthesia: Essays and Researches, 2012

Journal of the College of Physicians and Surgeons--Pakistan : JCPSP, 2004

Journal of the College of Physicians and Surgeons--Pakistan : JCPSP, 2005

European Urology Supplements, 2013

Research Journal of Finance …, 2011

The Journal of Physiology, 2006

Journal of Neuroscience, 2006

Separation Science and Technology, 1992

Proceedings of the National Academy of Sciences, 2006

NeuroReport, 2000

Journal of Regional Science, 1990

Journal of Pediatric Urology, 2009

Journal of Pediatric Urology, 2008

Journal of Neurophysiology, 2008

Journal of Neurophysiology, 2004