Peak to average power ratio reduction in NC–OFDM systems

Non contiguous orthogonal frequency division multiplexing (NC-OFDM) is an efficient and adaptable multicarrier modulation scheme to be used in cognitive radio communications. However like OFDM, NC-OFDM also suffers from the main drawback of high peak to average power ratio (PAPR). In this paper PAPR has been reduced by employing three different trigonometric transforms. Discrete cosine transform (DCT), discrete sine transform (DST) and fractional fourier transform (FRFT) has been combined with conventional selected level mapping (SLM) technique to reduce the PAPR of both OFDM and NC-OFDM based systems. The method combines all the transforms with SLM in different ways. Transforms DCT, DST and FRFT have been applied before the SLM block or inside the SLM block before IFFT. Simulation results show the comparative analysis of all the transforms using SLM in case of both OFDM and NC-OFDM based systems

ラホール市の既設BRT路線にアクセスする支線バスネットワークの設計に関する研究

横浜国立大学博士(工学)Now-a-days many developing countries are suffering from high motorization trend that has produced several unwanted by products. Though private vehicles provide high level of access and freedom but have enormous associated risks in the form traffic congestion and accidents, noise and air pollution and high energy consumption. Admitting these facts, many developing countries have initiated efficient mass transit systems to relieve these side effects. These systems provide a comfortable, safer and efficient services and so can be fairly preferred over private vehicles. Also the target of these systems is same as to cut down the private vehicle usage by attracting commuters from diverse social income classes other than low ones. However most of these systems are planned and designed independently, leading to the difficulties in accessing and egressing. Accessibility of these systems, which is one of the basic components of performance measure used for transit (Wardman 2004), is still crucial in most of the developing countries. Lack of any regular feeder services creates gap between ones’ origin and mass transits station that cause dissatisfaction to commuters and they lose patronage towards these systems. Currently paratransit is emerging as dominating feeder mode in several developing countries and connecting commuters from residence to public transport systems. However these paratransit have certain service areas and potential passengers. Also most of these are informal, not well organized and unsatisfactory and their movement is restricted to certain parts of the cities. Therefore a detailed evaluation is essential, also from commuters’ viewpoint, before implementing them as feeder. Unlike paratransit, a regular feeder bus, a form of public transport, can provide safer, comfortable and reliable service and will be free from the enormous risks as associated with paratransit. However a regular feeder bus requires a careful and vigilant planning and design. The precise selection of potential demand locations and appropriate approach to generate optimized feeder routes can result in the development of successful feeder bus operation. Optimized feeder routes can reduce the overall journey time of commuters while travelling in a comfortable mode. The purpose of the feeder route is to connect all the destinations for which demand generates from the mass transit station. All the previously proposed models for feeder routes generation are applied through conventional engineering approach; in which routes are generated separately for each station by assigning certain route generation nodes to a station. However a route generation node is a part of network and might be connected by some other stations too, its distance or travel time might be improved by inserting it in any other route for any other station. This issue remains unknown in typical approaches and some improvements are required to consider all or multiple consecutive stations simultaneously. Therefore this research intends to improve the conventional application method of route generation which can help in decision making by providing a set of solutions. The improvement in the current approach also aims to reduce the overall route network length to lower the operators’ cost. For this research, Lahore; the second largest city of Pakistan is selected as the study area. Lahore has a mass transit system in the form of Bus Rapid Transit System (BRT). Currently no regular feeder service is provided with the system and only existing modes are being used for feeder purpose. The existing modes are comprised of conventional public transport (public buses) and informal paratransit (auto rickshaw and motorcycle rickshaw). The role of auto rickshaws as feeder is almost equal to none being costly and fewer in number, whereas motorcycle rickshaws have made deeper inroads and are being used as feeder most frequently. In order to understand the current travel pattern and characteristics, two kinds of field interview surveys were conducted during Feb-March, 2015, with the help of university under graduate students. The first type of survey was conducted at few BRT stations comprising of 311 samples while the other was conducted nearby offices, workplaces and activity centres which made up 296 samples. The collected questionnaire data was analysed step by step and finally structural equation modelling techniques were applied. The results of the study revealed that currently major BRT users belong to low income class and those who own no vehicle. Among these users, work commuters are significant of all, which is also due to the location of BRT corridor that provides direct access to many workplaces. The commuters who own private vehicle and belong to other than low income class are more prone to use their own vehicle than BRT, even if they can make their egress trips by walk only. As far as the feeder mode is concerned, majority of BRT users are those who can make their access or/and egress trip by walk only. However the share of walk for the egress trip is dominant due to the proximity of workplace locations from BRT stations. After walk paratransit has greater share than public transport. For public transport, results of spatial analysis reveal that majority of city’s population is living far from the nearest bus stop and so cannot avail public bus as feeder. Whereas for paratransit commuters perception show that commuters are most dissatisfied by the vehicle quality as it offers bumpy, uneven and risky travel and also the service reliability. Further results show that in order to improve the BRT accessibility, all these dissatisfied factors must be dealt. Replacement of paratransit with feeder bus is a desirable option, also commuters show strong willingness to pay for the regular feeder bus. The study further suggests few preferred towns to initiate feeder service based on residential landuse type, owing higher density and uniformly populated. It also introduced an improved approach for optimized feeder routes generation. In the proposed improved approach feeder routes are generated, simultaneously for multiple adjacent (or for all) stations. The proposed approach yielded better optimization with lesser computational time and effort. The altogether insertion of all demand points for all the selected stations not only minimizes the average route length but total sum of all route lengths as well. This mechanism is found to be beneficial in achieving better trade-off between users and operators interests, when compared with the conventional approach. Therefore it is recommended to apply proposed approach to gain better optimization results. Based on the study findings, other developing countries must consider local differences and service area and passengers for various types of paratransit. In the end recommendations have been made for future work by proposing constrained multi objective optimization and incorporating other social income classes for evaluating paratransit.doctoral thesi

Frequency and clinical variants of specific dermatoses in third trimester of pregnancy: a study from a tertiary care centre

OBJECTIVE: To determine the frequency of patients with dermatoses in the third trimester of pregnancy and to identify various clinical types of dermatoses in the third trimester. METHODS: The study was carried out at the Department of Dermatology and the Department of Gynaecology & Obstetrics, PNS Shifa Hospital, Karachi, from January 2 to July 1, 2008. Two hundred pregnant women in their third trimester were included in the study. The diagnosis was based on history, clinical examination and relevant investigations. Patients with physiological dermatoses and dermatoses which flare up during pregnancy were excluded. A comprehensive pro-forma was used to evaluate different dermatoses. Skin biopsy for histopathology was also done where necessary. RESULTS: The age of the study population ranged from 17 to 36 years (mean = 27.3 +/- 4.86). Five (2.5%) patients had prurigo of pregnancy, 4 (2%) had dermatoses associated with Intrahepatic Cholestasis of Pregnancy (ICP), 3 (1.5%) patients had polymorphic eruption of pregnancy, and 1 (0.5%) patient had pruritic folliculitis of pregnancy. No case of pemphigoidgestationis was observed. CONCLUSION: In the study, 6.5% patients presented with specific dermatoses. Prurigo of pregnancy was the commonest condition. Polymorphic eruption of pregnancy was more common in primigravida, while dermatoses with intrahepatic cholestasis was seen more often in multigravida

COVID-19 pandemic & skin care guidelines for health care professionals

The Novel corona virus is bringing multiple challenges for health care professionals. Skin is the biggest organ and the first line of defense against different infections and external factors. Being the front line warriors, health care professionals are susceptible to various skin conditions due to prolonged use of personal protective equipment. These adverse skin conditions are redness, irritation, itching, contact dermatitis, and aggravation of underlying skin conditions like seborrheic dermatitis and acne vulgaris. In the current global situation, the potential incidence of such adverse dermatological effects does not in any manner cause the HCPs to deviate from the strict specific precautionary hygiene rules. These skin problems are manageable with the few precautionary measures. This article explores the different skin conditions that result from personal hygiene measures and usage of protective gear and will suggest some practical advice about how to manage and protect from these different adverse skin conditions

Treatment of Molluscum Contagiosum with 10% Potassium Hydroxide Solution

Background: To determine the efficacy and safety of topical 10% potassium hydroxide solution in the treatment of molluscum contagiosum (MC) .Methods: An open, prospective, non-randomized study of one year duration was conducted using 10% KOH solution to treat MC. Twenty eight patients completed the study. A total of seven appointments were planned; one baseline and six follow-up visits. 10% KOH was applied to molluscum lesions daily till the lesions resolved or till 3 months had elapsed.Results: Twenty eight patients, among which 22 were children, completed the study. The mean age of patients was 10.6 years. The total lesion count in the patients varied from 5 – 94, with the mean lesion count of 22.14 SD +_ 18.32. There was complete resolution of lesions in 20 (71.4%) of patients , 4 (14.3) had a near complete, 2 (7.1%) had partial and 2 (7.1%) patients had no improvement. 82% patients tolerated the treatment well with no side effects.Conclusion:10% KOH solution is an effective and well tolerated treatment for MC. It is less painful and cost-effective as compared to many well-established therapeutic modalities. It has the advantage of ease of application at home making it an acceptable and feasible option for the treatment of MC

Bilateral systematised epidermolytic epidermal nevus: A case report

Verrucous epidermal nevi (VEN) are benign congenital hamartomas consisting of keratinocytes. Histological examination mostly exhibits hyperkeratosis, acanthosis, papillomatosis and, rarely, the features of epidermolytic hyperkeratosis (EHK). We report a case of a 6-year-old boy who presented at Aga Khan University Hospital, Karachi, Pakistan with bilaterally symmetrical linear epidermal nevi following Blaschko\u27s lines and showing epidermolytic hyperkeratosis on histology. The patient was treated with topical keratolytics and emolients which led to considerable improvement. To the best of the authors\u27 knowledge, this is the first report of VEN from Pakistan

Impact of acne on quality of life in young Pakistani adults and its relationship with severity: A multicenter study

Objectives: The current study aimed to determine the effect of acne vulgaris on quality of life of young adults and to assess the correlation between acne severity and impairment of quality of life (QOLI).Methods: In this multi-center cross-sectional study, 163 young adults with acne vulgaris were assessed for severity and quality of life impairment between December 2016 and May 2017 at three tertiary care hospitals. Cardiff Acne Disability Index (CADI) was used to assess the quality of life while the severity of acne measured by Global Acne Grading System (GAGS). Data were collected on standardized forms, with CADI, GAGS scores, and sociodemographic data and analyzed using SPSS version 9. The quantitative variables were presented as means, median and qualitative variables expressed as frequency and percentages. P-value ≤0.05 was considered as statistically significant.Results: Out of 163 patients enrolled in this study, the mean age was 21.6 ± 4.9 years and 124 were females and 39 males. In mild QOLI, 56 (87.5%) cases were affected with mild, 11 (13.4%) with moderate and 1 (1.5%) case had severe acne. While, in moderate QOLI, 8(12.5%) cases were of mild, 60 (73.2%) were moderate and 6 (35.3%) cases affected with severe acne. The severe impairment of QOL noted in 11 (13.4%) moderate and 10 (58.8%) severe acne cases. The relationship between sex was statistically significant, (P\u3c0.001). The result showed significant correlation between severity of acne vulgaris and the quality of life impairment of these patients (P\u3c0.001).Conclusion: This study showed significant correlation between acne vulgaris and quality of life impairment. Cardiff acne disability index has proven to be a reliable tool to assess the quality of life. It is recommended to be used routinely in dermatology clinics to provide tailored treatment to individuals because mild disease may be disproportionately distressing for patients

Frequency of depression and anxiety among patients with chronic spontaneous urticaria visiting a tertiary care hospital in Karachi, Pakistan

Objective: To determine the frequency of anxiety and depression among chronic spontaneous urticarial patients presenting at a tertiary care hospital.Methods: The prospective, cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, from February to August 2015, and comprised patients diagnosed with chronic spontaneous urticaria at the dermatology clinic. All the participants were assessed for anxiety and depression using Aga Khan University-Anxiety Depression Scale. Data was collected in face-to-face interview using a structured questionnaire. The association of the condition with different characteristics were calculated after stratification for age, gender, occupation and monthly income. SPSS 19 was used for data analysis..Results: Of the 146 study participants, 84(57.5%) were males and 62(42.5%) were females. The overall mean age was 39±15.6 years. Of the total, 39(26.7%) had depression and anxiety. Depression and anxiety were more frequent among patients with a positive family history of mental disorders (p=0.02).Conclusion: Anxiety and depression were found to be considerably common among chronic spontaneous urticaria patients, with patients having a positive family history for mental illnesses particularly vulnerable

Neonatal Purpura Fulminans, a rare genetic disorder due to protein C deficiency: A case report.

Neonatal Purpura Fulminans is a rare and fatal disorder associated with perivascular haemorrhage and disseminated intravascular coagulation. Early clinical recognition, timely investigation and treatment is utmost important. A 6 days old baby boy was brought to emergency with blackish ulcers all over the body. Initially these were over the feet and scalp but later appeared on the abdomen. On examination, child was vitally stable, mildly icteric and had multiple erythematous large bullous blackish lesions on scalp, lower abdomen, perineum, back and soles. Neonatal reflexes and systemic examination was normal. Laboratory investigations showed normal CBC, PT/APTT and Protein S level while Protein C and Antithrombin III levels were low. Neonatal Purpura Fulminans is a life threatening condition and family screening is also mandatory for early recognition of disease in the siblings

Prevalence of clinical spectrum of cutaneous adverse drug reactions in patients presenting at a tertiary care hospital in Pakistan

Introduction: Cutaneous adverse drug reactions (CADRs) are the most common adverse drug reactions reported in the literature. CADRs have resulted in disabling infirmities during hospitalization and complications following outdoor drug therapy. The pattern of CADRs and the responsible drugs usually changes with the introduction of newer drugs and evolving clinical practices. Moreover, several international studies showed variable prevalence, emphasizing the need for local data in light of different socioeconomic and demographic practices. Therefore, the purpose of this study is to evaluate the prevalence of adverse cutaneous drug reactions and identify the clinical spectrum and any potential risk factors.Methodology: The current study is a descriptive cross-sectional study conducted at Aga Khan University Hospital, Pakistan. One hundred ninety-three patients who met the study inclusion criteria were included. Data were collected from patients on a proforma after taking informed consent. Quantitative data were presented as simple descriptive statistics giving mean and standard deviation, while qualitative variables were presented as frequency and percentages. Effect modifiers were controlled through stratification to highlight the effect of these on the outcome variable. The post-stratification chi-square test was applied and the p-value of ≤0.05 was statistically significant.Results: A total of 193 patients who had cutaneous adverse drug reactions were included in the study. The mean age in this study was 47.78±8.33 years. One hundred eight (56%) were male and 85 (44%) were female. Out of 193 patients, 135 (69.9%), 50 (25.9%), 24 (12.4%), 12 (6.2%), 20 (10.4%), 11 (5.7%) and six (3.1%) had maculopapular rash, acneiform eruptions, Stevens-Johnson syndrome, erythema multiform, urticaria, fixed drug eruptions and toxic epidermal necrolysis, respectively.Conclusion: CADRs are a common clinical presentation and awareness and knowledge about their diagnosis and prevention is important. It can be assumed that in our local setup, the clinical trends and medications causing ADRs are strikingly similar to those found in other countries. Physicians commonly come across these cases and they should be well aware of the clinical spectrum of skin reactions to enable early diagnosis and management