1,764 research outputs found
Effects of construction delays on construction project objectives
Delays can be defined as the late completion of works as compared to the planned schedule on the contract. Delays can be avoided or minimized only when their causes are identified. When delay occurred in to our project, it will have adverse consequences on project objectives in terms of time, cost and quality. The aim of the study reported in this paper was to identify the effects of delays that could threat project objectives in construction projects. A comprehensive literature review from various sources through books, conference proceedings, the internet, and civil engineering journals was made to carry out the study. According to delay categories that were contractor related, client related, consultant related, labor related and external related, the results of this study identified the six major effects of delay that were time overrun, cost overrun, dispute, arbitration, total abandonment, and litigation. The study also revealed that time and cost overruns were the frequent effects of delay. It is hoped that this study will become the foundation of further research in the area of project delays and mitigation measures
Electroweak phase transition in the presence of hypermagnetic field and the generation of gravitational waves
We investigate the effects of a large-scale background hypermagnetic field on
the electroweak phase transition. We propose an effective weak angle which
varies during the electroweak phase transition and upon its use, show that for
a strong enough hypermagnetic field the phase transition occurs in two steps
and becomes first-order. We obtain all of the important quantities
characterizing the details of the phase transition, including the latent heat,
transition temperature and duration. We then explore one of the consequences of
this model which is the generation of gravitational waves. We calculate the
gravitational wave energy spectrum generated during the first-order electroweak
phase transition and find that, for strong enough background hypermagnetic
fields, these signals can be detected by the Ultimate-DECIGO interferometer.Comment: 19 pages, 7 figures; v3: more discussions adde
Vertical velocities from proper motions of red clump giants
We derive the vertical velocities of disk stars in the range of
Galactocentric radii of R=5-16 kpc within 2 kpc in height from the Galactic
plane. This kinematic information is connected to dynamical aspects in the
formation and evolution of the Milky Way, such as the passage of satellites and
vertical resonance and determines whether the warp is a long-lived or a
transient feature.
We used the proper motions of the PPMXL survey, correcting of systematic
errors with the reference of quasars. From the color-magnitude diagram K versus
(J-K) we selected the standard candles corresponding to red clump giants and
used the information of their proper motions to build a map of the vertical
motions of our Galaxy. We derived the kinematics of the warp both analytically
and through a particle simulation to fit these data. Complementarily, we also
carried out the same analysis with red clump giants spectroscopically selected
with APOGEE data, and we predict the improvements in accuracy that will be
reached with future Gaia data.
A simple model of warp with the height of the disk z_w(R,phi)=gamma (R-R_sun)
sin(phi-phi_w) fits the vertical motions if d(gamma)/dt/gamma=-34+/-17
Gyr^{-1}; the contribution to d(gamma)/dt comes from the southern warp and is
negligible in the north. The vertical motion in the warp apparently indicates
that the main S-shaped structure of the warp is a long-lived feature, whereas
the perturbation that produces an irregularity in the southern part is most
likely a transient phenomenon. With the use of the Gaia end-of-mission products
together with spectroscopically classified red clump giants, the precision in
vertical motions can be increased by an order of magnitude at least.Comment: Accepted for publication in A&A. arXiv admin note: text overlap with
arXiv:1402.355
The Experiences of Family Members of Non-Organ Donors on the Crisis Rising From Patients' Brain Death
Background: Brain death crisis as an overwhelming situation can create a critical state for families in which they are unable to
make logical decisions for their patients with brain death.
Objectives: This study aimed to explore the experiences of family members of patients with brain death, who did not donate their
patients’ organs.
Methods: A qualitative study was conducted on nine non-donor family members of patients with brain death, selected using the
purposeful sampling method. To collect data, deep unstructured interviews were held to reach data saturation. The interviews were
transcribed verbatim and analyzed utilizing the phenomenology approach based on the seven-step Colaizzi’s method.
Results: The participants of this study explained their situation as ‘an overwhelming situation in families due to patients’ brain
death’. Also, the data analysis led to the development of four main themes as follow: ‘overwhelming situation’, ‘perplexity factors’,
‘the sling loops of defect in consent for organ donation’, and ‘compatibility’.
Conclusions: The overwhelming effects of the patients’ brain death on the family members and the crisis rising from it influenced
the decisions made by family members for organ donation. Therefore, some measures should be taken to cultivate appropriate
adaptive behaviors among family members for relieving their sorrow and pain. Moreover, healthcare team members should be
informed of the crisis raised from patient’s brain death and help family members make logical decisions with regards to organ
donation
Scintigraphy with 99mTc(V)-DMSA in monitoring patients with inflammatory bowel disease
The clinical significance of pentavalent technetium-99m dimercaptosuccinic acid (99mTc(V)-DMSA) scintigraphy in diagnosing inflammatory bowel disease (IBD) has not yet been fully elucidated. The aim of this prospective paper was to study the above. This study included 54 patients, 22 females and 32 males (mean age: 36.68±11.49; range: 18-63 years) with IBD who came to our clinics for follow-up and were examined clinically by colonoscopy and 99mTc(V)-DMSA scintigraphy. On the follow-up studies, five patients (9.25%) relapsed, and 49 (90.74%) remained at a steady condition. There was a good correlation between the scintigraphic results and the clinical and colonoscopy data of the patients (P<0.05). In conclusion, our results indicated that 99mTc(V)DMSA scintigraphy can be complementary to colonoscopy for the diagnostic evaluation of IBD
The evaluation of base deficit as the predictive agent of mortality in geriatric trauma
زمینه و هدف: کمبود باز (Base deficit) به عنوان یک عامل مرتبط با کاهش پرفیوژن نسجی مخفی شناخته شده است، لیکن نقطه بحرانی مؤثر در ایجاد این حالت و مرگ و میر به دنبال تروما تعیین نشده است. در این مطالعه ارزش پیشگویی کننده کمبود باز در مرگ و میر و نقطه برش آن در افراد سالمند مورد بررسی قرار گرفت. روش بررسی: در یک مطالعه تحلیلی - آینده نگر 300 بیمار سالمند (سن بالاتر یا مساوی 65 سال) مبتلا به تروما در مرکز پزشکی الزهراء (س) دانشگاه علوم پزشکی اصفهان مورد بررسی قرار گرفتند. از هر بیمار گازهای خونی آنالیز شده و مقدار کمبود باز محاسبه گردید و عوامل مؤثر در تغییرات کمبود باز مورد ارزیابی قرار گرفت. وضعیت بیماران تا زمان ترخیص و یا مرگ پیگیری شد و عوامل مؤثر در مرگ بیماران نیز مورد بررسی قرار گرفت. جهت تجزیه و تحلیل داده ها از محاسبه رگرسیون استفاده شد. یافته ها: نتایج این مطالعه نشان داد که در افراد سالمند مبتلا به تروما و علائم حیاتی پایدار، کمبود باز تنها عامل پیشگویی کننده مرگ می باشد (01/0
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