The high androgen levels in women (mild to moderate AD) in low stress environments showed the altered metabolism of the androgens. The significant correlations between DHEA and cortisol, androstenedione and cortisol indicated that hormone production in the adrenal cortex of the kidneys were like that of younger people. In another study mentioned in this paper, associated high levels of cortisol and DHEA with cognitive dysfunction. There were higher chances of performing better with lower levels of DHEA. Later in the study, they had said that further investigation was required to assess the androgen and gonadal hormone metabolism as they had only reported increased basal androgen levels. In another study, they investigated the thyroid hormone levels in the cerebrospinal fluid (CSF – present to keep the brain afloat and washout any toxins) and found a correlation to the AD severity in patients with normally functioning thyroids. Thyroid hormone (TH) helps in metabolism in the brain and hence can be found in the CSF. There are several forms of TH – they are usually numbered as T2, T3, T4etc. They used something called lumbar puncture to extract spinal fluid from people (sounds pretty painful!). They used highly specific techniques called mass spectrometry and high performance liquid chromatography to assess the CSF containing thyroid hormones. They had about 35 patients (9 males and 26 females, approximately 66 years). The CSF TH concentrations were representative of the blood TH concentration. The AD patients were diagnosed through CT scans, neuropsychological tests, MRI and Mini-Mental State Examination (MMSE). The control group had 10 subjects with normal cognitive abilities and normal MMSE. They had undergone lumbar puncture due complains of severe headaches. Exclusion criteria included thyroid problems, abnormalities of CSF routine analysis or any proof that the barrier between their blood vessels and brain was damaged by in depth analysis of the CSF.
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Intersexual selection in animal behavior involves mate choice, usually done by the female because they invest more energy into each offspring. Some direct benefits that may come from a choosy female include nuptial gifts, parental care, territory quality, and resource benefits. Nuptial gifts are presents a male might bring a female to encourage her to mate with him. These are often prey items, such as in the empid fly, spermatophores, such as in insects or salamanders, or actual body parts of the partner, like how female crickets are allowed to gnaw off the wing of a male they are mating with. Being choosy can benefit the female by providing her with better parental care. This is true in stickeback fish, where males with red bellies are preferrable since they indicate that he will be better at fanning the eggs with oxygen after they are fertilized. Territory quality is another way the female benefits from being choosy. Lots of female birds will assess a territory established by the male before choosing him, ensuring her a safe place to mate and rear her young. Lastly, there are other resource benefits a chosen male may provide. In chimpanzees, males provide the females with food, and in dung beetles, males provide a dung ball for food and a place to mate. These hypotheses are not mutually exclusive, meaning that in any given species more than one can be true at any time.
Bateman’s principle states that variance in reproductive success is greater in males than females. Females always invest more energy to produce their offspring. Sperm are cheaper than eggs. Males reproductive success is limited by the number of mates. Female reproductive success is limited by how many eggs she can produce. This results in sexual selection in which males compete with each other. And females become choosy in which males to choose. As a result of Bateman’s principle, the predictions follow; males should try to mate with as many females as possible and should compete with other males for female attention. Females should try to choose the best mates. In addition, we expect higher variance in reproductive success in males compared to females.
People who have RP4 goes through unique challenges that result from their vision loss. In patients with RP, the disease usually starts in childhood when patients find that their eyesight takes a long time to adjust to the dark. This is followed by eventual loss of night vision altogether, which the patients often describe as though they have walked into a dark room with sunglasses on. This is followed by the loss of peripheral vision, where the field of vision becomes narrower and narrower until complete blindness. Despite the devastating effect of this disease on the quality of life in patients, RP is not fatal, and as a result, the lifespan of those who suffer from the disease is not affected. People who have RP generally know that they may also have RP because their family members have RP. Because RP is a degenerative disorder, people with RP find it harder to accept and adjust to being blind than people who were born blind. However, patients of RP also tend to adjust better than people who lose their sight suddenly as they have time to prepare for the eventual sight loss. Some of the adjustments that come with the loss of sight are, learning to use a walking stick and braille. Other challenges that are posed by the disease are there is a need for adjustment in jobs and loss of ability to drive. However, despite these challenges and adjustments, people who have advanced RP also have said that the disease was not as bad as they thought and that even though they are blind, they are still able to participate in society, which was not something that they expected.
Prior to the methods project, I have never had an assignment where we were to write the way we did. It was tough at first to give direction in my methods project without telling the reader what I actually did to get the result I did. With practice in writing my drafts, I began to find the methods project running smoothly. Although there was a lot of out of class work to do, the project was very interesting to see how well I could follow someone’s methods to recreate a multi-panel scientific panel I have never seen before. Surprisingly, the end result for most of the classes replicate figure looked very close to the original. There were plenty of differences in each replicate, but for the most part, most replicates looked similar to the original. This meant that I was able to write in a way that others were able to understand and follow. The methods project allowed me to practice writing a methods section in the future for a scientific paper.
Embryosis is the formation of an embryo. There are two main steps to this process: blastulation, and gastrolation. The sperm and egg cell must fuse to form a zygote. The fusion of sperm and egg allow the genetic material to merge, all cells are pluripotent at this point. Clevage, compaction, and differentiation follow which form the blastocyte. The overall size of the blastocyte is not much bigger than the zygote, due to compaction. There is differentiation between cells in the blastocyte at this point. Gastrolation is the formation of three distinct layers in the blastocyte which will differentiate into different tissues in the bdoy. The top layer is the ectoderm, the middle layer is the mesoderm, and the bottom layer is the endoderm. The ectoderm differentiates into the nervous system and the skin. The mesoderm differentiates into the muscles; the endoderm differentiates into the internal organs. This process is virtually the same for all mamals. The outcome is very different because of the genetic information fused, resulting in a wide range of organisms.
The paper on song sparrows studies the effects of the transfer function, reverberation, and noise masking of the environment on the trill song of chipping sparrows, with a focus on divergent solutions as a result of intraspecific song variation. A transfer function is a way of describing how the environment filters sound and causes frequency pattern degradation. Urban environments often have transfer functions which favour an intermediate frequency range above low frequency background noise but below frequencies that easily reverberate. Reverberation is a temporal pattern distortion that contributes strongly to impeding signal transmission by adding a tail to notes. As sound waves impact objects they are reflected, which can lead to slurring of both syllable form and pattern. Additionally, due to reverberation, sounds take different paths that can cause both amplitude and frequency interference. The effects of reverb are most pronounced in signals of high frequency, high bandwidth, high duration, and low internote time. In order to compensate for reverberation high obstruction environments such as cities, birds often change their signals by: decreasing minimum frequency, decreasing the number of amplitude and frequency modulations, and increasing internote time. However, in order to transmit their signals above background noise, birds tend to increase the frequency and amplitude of their vocalisations. Although, these modulations can often be hard to separate due to the Lombard effect. Lastly, amplitude and frequency modulated trills are often used by female songbirds as measures of vocal performance, based on how close the male sings to the biophysical limit of the bandwidth to rate ratio. Males which sing closer to this limit are preferred by females and can better defend their territories. In urban environments with highly reflective structures and high background noise, trills suffer heavily from the effects of reverberation and therefore vocal performance is perceived as being poorer. In turn, this has an effect on how well males can both attract females and defend their territories, which means that urban environments could generate unique intra- and intersexual selection pressures.
The goal of our project was to observe the effects that manipulating the seed coat had on germination rates in soybean species. The seed coat is important for protecting the seed, but we were wondering if it is at all necessary for initial growth to occur. To test this, we had some serve as a control group, some where the coat was nicked with a needle, and some where the seed coat was completely removed. Over the course of 3.5 days, the seeds stayed in petri dishes with wet paper towels, and we periodically checked all the seeds and recorded how many of each treatment had germinated. Because another group completed this project with us, we focused mostly on how the control group's germination rates differed from that of the nicked group. Our results showed a trend in faster germination among the nicked seed coats, but after statistical analysis we cannot conclude that nicking of the seed coat leads to faster germination. We must say that the differences observed most likely occurred by chance.
One main feature of music is that it can elicit a host of different emotions. Autobiographical memory is the long term memory that allows recovery of experiences and knowledge. One autobiographical component is emotion, which helps to remember certain memories than when emotions are not involved. Thus this current study tried to find a link between emotions and music-evoked autobiographical memories in AD. They asked the subjects to choose their favorite music as they hypothesized that favorite music hold high emotion valence. When asked about their favorite music, some were unable to name them and so their family helped out by naming it. After going through the conditions, they were asked for any details they remembered. They were rated using TEMPau that measures autobiographical memory – zero for absence of memory and ranging up to a four for feelings, emotions, thoughts and perceptions. The emotions were categorized as positive or negative and rated accordingly. The results showed amazing results for the chosen condition: the controls scored an average of 4 as expected, but the AD patients had scored 3.33. Furthermore, they produced more positive words than negative, and hence the autobiographical memory relevant to it.
Theories for invasive species and why they occur have been hypothesized in recent ecological research. These hypotheses cover a variety of thoughts and multiple may be true concurrently: the enemy escape hypothesis, EICA hypothesis, EDCA hypothesis, Novel Weapons hypothesis, Missed Mutualism hypothesis, Invasional Meltdown hypothesis, Biotic Resistance hypothesis, unusual refuge hypothesis, global competition hypothesis, introduction pressure hypothesis, unintentional screening hypothesis, intentional screening hypothesis and the related idea of biological control corollary. The enemy escape hypothesis states that species are less subject to specialized predators and pathogens where they are introduced than where they are native. This is due to the lack of selection for a specialized predator where the organism was not existing. The EICA (Evolution of Increased Competetive Ability) hypothesis is where plants evolve to grow faster than other plants. EDCA (Evolution of Decreased Competitve Ability) hypothesis is where plants evolve to reproduce faster than other plants, but have no competetive ability. Novel Weapons Hypothesis explains how native species have not evolved to be selected for defenses against introduced species. This means that the introduced species defense mechanisms are more likely to target and harm the native species. Missed Mutualism Hypothesis states that the invading species will be less likely to take over it if is introduced without its native mutualists because it no longer benefits from the relationship with them. The opposite is true of the Invasional Meltdown Hypothesis which discusses the idea that if the mutualists of an introduced species are brought with it, the species will be highly invasive and almost always win out. The Biotic Resistance Hypothesis states that introduced species are less likely to be invasive because the presence of native predators, pathogens, and competitors will limit their spread. The idea that specific location yield species that are highly specialized to live there and only there comes into play in the Unusual Refuge Hypothesis, where it is thought that lack of adaption to local stresses limits invasive-ness, then locations with unusual stresses are less invasible. Global Competition Hypothesis simply states that it is more likely that some species elsewhere is a better competitor in a single niche than the local species because of the opportunity for better plants to be located and adapted to any other location on the planet. The introduction pressure hypothesis believes that the greater the number of individuals of a species are introduced and the more times that species arrives, the more likely it is to take hold in the introduced environment. That is because increasing the number of individuals reduces the limitations on the genetic pool of the migrated population and decreases the affects of genetic drift, and interbreeding between previously separate species populations increases fitness. Intentional screening causes certain traits that are more likely to yield an invasive species to be artifically selected for when people pick plants to bring. The unintentional invasion hypothesis deals with the traits that a plant species is likely to have to have survived travel and dispersal to become invasive. Plants that cling to boats and crops and survive travel are likely to be more drought tolerant, more fecund, parasitic to plants that were intentionally brought, and from places disturbed by people and therefore disturbance tolerant. The biological control corollary is the idea that a specialized predator from the native location of an invasive plant can be brought to reduce the invasive-ness of that plant.